I was under the impression I was missing out not having one of the expensive RF lasers. Now my glass tube laser looks much better once I finish it :-). Thanks again.
Hi Russ That was quite an interesting comparison. We are here at the entry level glass tube, and always looking longingly at the supposedly superior RF lasers. You have shown us we need to better exploit what we have, you have me intrigued with your upcoming instalment! Cheers Ralph
I bought a laser from Epilog which had numerous problems and caused me many years of grief. Now I have a Thunder laser and it has been a far more enjoyable experience so far. Thanks for the videos Russ.
Another great video. Proving in this case less is more. And a rear bomb shell at the end. Can't wait to see what you come up with. Exciting times ahead
Another interesting video Russ. My metal tube, which is a 30W, is no where near to your 500+W input. My entire system which includes an extraction fan, laser, Galvo's and PC all draws less that 600W at full power. My metal tube has a power supply rated at 10A 48V 480W. On average it draws about 5Amps which is about 240Watts. Using an oscilloscope with a shunt resistor to measure the current, it spikes at about 10A only at the very beginning of the pulse cycle and then drops down to about 3.5Amps. I can do hour long engravings and only feel a small amount of warmth on the tube, and the ambient air temperature does not noticeably increase, which would not be the case if 500+W of heat where being pumped into the air. Your efficiency chart vs my data are very different. My CO2 is listed as having an efficiently of 12%, which means only 12% of the input power is converted to light energy, the remaining 88% is heat. That is a factor of 8 and if you do that numbers, my 30W should input at 250W, which is pretty close. As my CO2 marking machine is a Galvo (like your lotus fiber, only a CO2) and is only used for engraving, I use a beam expander to bring it up to 12mm. Then it focuses down to a nice small point. The focus point is critical on this machine, but I can engrave at 508DPI (0.05mm dot size) with exceptional quality images. Another advantage of the galvo when used with a high speed RF is you can use what is called drill mode, and produce dots, not lines, but this is a little slower. My 30W is rated up to 100kHz. Which i need when engraving at 508DPI at 3000mm/s, which required 75,000 dots to be burnt per second, so I set it at 75kHz. This type of speed on not possible on a glass tube. Another big advantage of the RF laser over a glass for engravers, at least for my tube, is that my tube is rated to maintain >90% of it's output power over it's 40,000 hour life. Glass tubes are usually only rated for 10,000 hours and the power will drop off as they get older. I have seen this happen over the years, and while technically the glass tube laser still worked, the power output had decreased enough that the engravings where getting faint. No such problems with the Metal RF so far. I am trying to find the info, but I had read that the M.2 beam quality of a glass tube is also affected by it's power. As you reduce the current to the tube, the more unstable the beam becomes. RFs do not suffer from this. Some specs will show the M.2 quality at a given power level for this reason. I 100% agree that glass tubes are better for cutters, but for purpose built engraving/marking machines, the much faster switching speed and consistent beam quality of an RF is a winner. I have both Glass and RF, used for completely different purposes.
Hi John As always, your expertise is a valuable contribution to extending my horizons. Your detailed information is absolutely brilliant and only goes to fine tune the basic comparison I made. Photo engraving is one of the weakest aspects of the technology but I suspect It will excel at normal engraving and 3D engraving but be pretty poor at cutting. The fact that you have dedicated cutting and engraving machines tends to confirm that expectation. I will never be able to drag the existing motors/mechanics up to 3000 mm/s but I hope to make a few more small changes that will allow me to reach 1,500mm/s and not have massive overruns. I have two goals for this project. One is to find the extreme mechanical performance envelope of that very basic piece of cheap engineering and secondly to examine and understand what is so special about the RF laser that it justifies the premium price. I would estimate that more than 99% of people with this RF equipment have bought it to use and trusted the "experts" to created an "amazing" technology. They are not going to spend time digging into the minutia of how science is being employed, but understanding this detail is what fascinates me. The drill function of the galvo system is truly wonderful and I employed it to great effect when engraving slate. Sadly Lotus have "un-loaned" the fiber machine because they had an urgent sale they had to fulfill..... but it was a great learning opportunity. Thanks again for sharing your years of professional experience and I always appreciate your insightful comments. Best wishes Russ
rf lasers are great for very fine and fast engraving. they operate at a higher frequency compared to glass. We have both types, and also a dual RF 60watt + 60Watt Universal, with beam combiner. just one tube is fired for fine engraving, at fast speed, and high pulse rate - and for cutting 25mm acrylic in one pass using both rf units on full power.
There is no comparison an RF Laser will out shine a Tube in the long run, give cleaner straight cuts, razor sharp engraving, you really have to experience the two to know the difference. I want to upgrade my Chinese asap and I never knew it was possible until I found your channel
Hi Farouqi You are right to say there is no comparison BUT it depends on what your needs are. The one and only advantage I can see for RF technology so far is the instant switching speed that allows crisp engraved images at high speed PROVIDED you have the power to keep up with the speed. There is no miracle in RF technology it is the same CO2 laser beam, the same lenses, but the tube is configured to always sit in standby mode to give this instant switching capability.. As I have already discovered, it is not very good at the one goal I had for the machine, fast photo engraving. Even with my compound lens system the RF cannot match the quality I achieve on a glass tube machine. see ua-cam.com/video/ATu-7EGZGMA/v-deo.html For cutting there is only one thing required and that is power. It will be an eye-watering cost to upgrade with a 80 or 100 watt unit. With the 20 watts available to me I will not be doing much cutting or even 3D engraving. If I can cut 3mm material of any sort I will consider myself lucky. That is in the next session that I will do some cutting. I am not a salesman or a teacher, I am just a student who wants to understand the technology. Like so many other people, I have listened to all the marketing hype around the expensive RF machines and wondered exactly what the magic was. I have watched many carefully edited slick demonstration videos and spotted all sorts of technical issues so it was with a serous enthusiasm for the technology that I have embarked on this learning journey. I trained as production engineer and have spent millions on equipment purchases for big companies I worked for. As a value for money investment I could never recommend this technology based on what I know so far. If you run a niche engraving business you may consider it BRIEFLY but to be honest a much better investment to do CO2 engraving, would be an RF unit strapped to a Galvo head. Much cheaper, faster and more compact. If you specialize in cutting then speed is of no value because cutting requires power and you can only go as fast as your power allows , maybe 20 or 30mm/s . What is the point of high speed servos and hideously expensive laser source? I am enjoying my trip into the RF world but on the basis of what I am finding so far you maybe the only one to follow my lead. Many thanks for your comment Best wishes Russ
I’ve run 60 and 100 watt BOSS Laser glass tube machines for 6 years now with wonderful results (and company service) but always wondered what I might be missing from an RF machine. This video breaks down amazingly why I shouldn’t have even given it a second thought. I’ve recommended your videos for every new laser owner I’ve spoken to since discovering them myself. Russ, have you considered making a square shaped window that will attach below the nozzle to artificially force a square beam shape and achieve a square pixel? By shaving the edges of the round beam it may be possible to get a more consistent power level within the area of the “pixel”.
This is another great video Russ. The way that you explain things in such a clear to understand manner is excellent. It should be noted that not all RF lasers are the same, however, most decent DC lasers have very similar performance specs. Therefore, the comparison for some of the tech specs very much depends on which RF you compare to which DC. As you point-out, the main reason for investing in an RF is the rise/fall time, typically 75us for a decent metal laser with integrated RF. In industry other factors such as integration space, movement of the laser source, etc also dictate an RF must be used. RF lasers will perform better at very low duty cycles and RF lasers will have better power stability, assuming cooling is working well. Some RF lasers can be pulsed too so that Peak Power exceeds Average Power usually by a factor of x3 while CW lasers of RF or DC type will have a peak power roughly the same as max average power. Some of the Pulsed RF lasers out there have a much better M2 too. For example, the Coherent J2 will be 2mrad. In a plotter format machine it's hard to justify the cost/benefit of using an RF laser, which is why virtually all of the
Hi Dean Another machine? Another wavelength? Sounds interesting. I had better hustle on with my RF project!!! This project is specifically aimed at making a fast RF engraving machine by joining together a few low cost Chinese major components that other hobbyists can easily replicate for themselves. My comparison specifically excluded the specialist tubes that deliver high power pulses and/or that have very low divergence similar to glass tubes.. These tubes are beyond the budget of even enthusiastic hobbyists who may spend between $6K and $8K, to build their own 40 to 60 watt version. I have many correspondents that lust after one of those top brand RF machines. The marketing hype and snake oil salesmen that appear in their dodgy videos, seem to work on the less cynical part of the population that see it as a "must have" for their workshop. I'm sure you know that cynicism is encoded into my DNA , so despite wondering if there is any real "magic" in this technology , my goal was to sort the facts from myth and either justify or cure the longinging of those many correspondents. At the same time, secretly, I was really hoping to find some magic that was going to make 20 watts perform out of it's skin (like the 20 watt fiber laser) Although I intend looking in depth at normal engraving, 3D engraving, grayscale photo replication and cutting. I started this project with the rather demanding photo engraving process. It afforded me the opportunity to examine how and what signals the Ruida controller delivered to the tube and to see just what sort of effect ultra fast switching had on various common materials. When I saw how the PWM was working, I also imagined that a short duty cycle at the right frequency to match resolution and speed would result in nice dots., Im fact , 20 watts made zero impact. When I did manage to get enough colour/penetration, the switching speed was so fast that it turned the beam on and off exactly on the edges of an individual pixel. Can't complain about response speed BUT it left half a dot before and half a dot after resulting in a 2 pixel burn for a 1 pixel signal. This was VERY bad news for diffusion (Floyd Steinberg) dithered images. and explains why all the big companies use the much cruder half tone screen method. My next video investigates this method and suggests a much neater method I have devised to achieve more photo realistic results without that pencil sketched cartoon look. Thanks for your valuable facts regarding the process from a " top end" industrial perspective. I can see that various aspects, like no dangerous high voltages. maybe better output stability and predictable response speed are factors that make this process attractive where the high cost can be justified, It seems that you are in effect predicting what I already am beginning to feel about this project ......... that this is not a jack of all trades hobbyist technology . Best regards Russ
You got me laughing hard at 25:22 All I can say is that I am relieved that I did not completely wasted my money in a glass tube machine (it could have been better, but also it could be worse :P). Yet another master class, Russ. Thanks for sharing.
I have had two of each type of laser, glass tube and RF. The advantage of glass tubes is cost. You can have about 5 glass tube units cutting out bird houses for the price of one RF unit. The advantages of the expensive RF units are first kerf size. Glass tubes are usually about 0.25 mm. RF units are about 0.07 mm. the kerf size is 28% of the glass tube. This means that the beam is concentrated 3.5 as dense. My 30 watt RF cuts slightly faster than my 90 watt glass and with a much finer cut. Another advantage of the expensive RF units is that they usually have servo motors in lieu of steppers. Servos are much more accurate, smoother and move much faster. Because the kerf is so fine, RF units are only burning a slot 28% as large as the glass tubes and produce much less smoke to dirty the work piece. Last, RF tubes can produce full power without affecting tube life. A 30 watt RF can produce a continuous 30 watts. A glass tube us recommended to not exceed 70% power. So a glass tube 90 watt unit is limited to 63 watts. A RF unit can also go down to 1% power with no problems. Most glass tubes will not fire at much less than 5 or 10% power. If you are cutting or engraving fine paper of thin veneers, the RF tubes work much better. If expensive RF laser machines did not have these advantages, no one would buy them.
Hi Dennis Since this video 2 years ago I have done a lot more experimental work with lenses and laser beams. I have demonstrated that there is a strange relationship between the beam size, intensity profile and watts entering a lens and what gets focused into a destructive "spot" of energy. Your assumption about energy density is based on the belief that the beam. is like a stage spotlight and is of uniform brightness (intensity) when it hits the material. In actuality the intensity profile at the focused spot is not even a amplified replication of what enters the lens. I have spent the last 4 years on and off trying to understand how it is possible for this to happen when everything we are taught about lenses says it's logically impossible. See this 30 sec video ua-cam.com/video/vTEAm-01E1Q/v-deo.html Yout kerf width observation my be your experience but it has nothing to do with the source of the laser beam. It is entirely dependent on the lense type, the lens material, the focal length of the lens , the orientation of the lens and most importantly the diameter of the beam.. All my videos of me exploring these factors are on you tube if you care tto watch grass grow.. The fact that your 90 watt tube cannot cut as well as your 30 watt RF, is iindicative of poor beam quality from a B grade tube.. My 70 two watt glass tubes cut 3mm birch ply at 40mm/s whereas the 30 watt RF can just about get to 25mm/s. You seem to be a bit confused about steoppers and servos. real dc servos are smoother in their action but they cannot CUT faster. Cutting speed has nothing to do with the motor speed and is all to do with the relationship between power and the necessary exposure time of the beam at the material interface to produce a cut, Speed is only a asset for high speed engraving (that's another subject). Regardless of kerf width, "dirty" work should not happen if ALL your smoke fumes exit thre BOTTOM of the cut. Is there a problem with your air asist ? The way the two technologies work is completely different. First you cannot control the POWER of an RF tube because it is ALWAYS working at full 30 watts The only thing you can do with an RF laser is swith it on and off for variable amounts of TIME.and that is the function of the PWM control system. You can vary the switcing frequency and the %power is changing the ON/OFF ration for every cycle. You are ALWAYS hitting the material with 30 wats. Not so with the glass tube technology You are genuinely changing the power that CONTINUOUSLY arrives at the material surface. The big difference is that the INTENSITY profile changes with power for a glass tube but remains constant for an RF tube. You are not power limited with a glass tube, however the manufacturer does specify a maximum allowable current flow through the tube to achieve the expected life of the tube. If your tube is a specified as working 90 watts (maybe its a Reci W2?) then you can run it at about 26mA and get the 90 watts promised. However iif its a Reci W1 then the PEAK rated power is 90 watts and is a factory TEST value and not one you can ever use The W1 is rated at 75 watts and should be run at 23mA max. The %power is not directly related to watts but is all to do with the max current flow that your HV power supply can deliver.. It is true that you can run a n RF tube at 1% power but as I mentioned earlier this is not 1% power butthis is a pulsing 1% exposure time for 30 watts. Tthe RF tube has no preionization zone, and this switches on and off (for all intents and purposes) instantly. it operates completely different to a glass tube that does have a preionization zone that under certain circumstances can be VERY slow at swithing the tube on and off. It is this strange zone that is the reason why you dont see much power until a certain % power. That % power varies betwen tubes and manufactureres. BUT it is vitally important (if you understand how to find it ) for cutting veneers, card and paper at very high speed without charing, smoke or burning. see this example of card cutting using the preionization zone of a glass tube. ua-cam.com/video/S_2NOCpACVc/v-deo.html Your final point about buying an RF machine. The marketing is intense and conjours with the truth. I was looking for the "magic" in RF technology awhen I built this machine and was very disappointed. I have recently discovered the secret of how o do amazing high speed photo replication with the RF laser ....not the terrible cartoon engraving that Trotec and Epilog demonstrate. RF cutting ability is poor for reasons that I now fully understand unless you spend mega bucks on high powe tubes . My local plastics distributor is one of the UK's largest and does a LOT of laser cutting of acrylic up to 25mm thick. It has a Trotec RF machine for label and sign engraving but has two large glass tube machines ( 150 and 200 watts ) for fast and efficient sheet cutting. Trotec and Epilog were non-contenders in the cutting arena. So it's not just my personal experience. Thanks for the comments.. It has allowed me to add two years of in-depth experience with both technologies to my initial comparisons. That strange relationship I mentioned earlier between laser beams (from any source) and lenses is summed up in this video and you will see thaewierd things that happen at the "so-called" focal point. ua-cam.com/video/kddSFO-iFNM/v-deo.html Best wishes Russ
Having had a couple of each type, the reality is that the RF tubes cut cleaner with a much smaller kerf. You can really tell the difference when you compare the smoke produced. Little smoke from the RFs, much more smoke from the glass tubes. Might be the optics. I suppose a $5000 RF unit may be more precise than a $300 tube. If you are just cutting plastics, I would go with the much cheaper tubes and I have. I have several CNC machines, plasma, milling, laser, routing, and there is very noticeable difference in the cut quality depending on the prime mover.. The servos move with 0.0001 inch accuracies and the steppers move in 0.04 accuracies. I suppose a GCC laser not only has a smaller kerf, but also a better controlled kerf. It shows. Software makes a huge difference. I belong to a makers group with a FSE tube 90 watt laser (the one that used to be in my shop.) It started to get a bit wonkie when rastering. The group swapped out to a Riuda controller and Lightburn. Every aspect of the FSE became better. The steppers are much smoother and better controlled. I suspect much less wobble in the path. If you remove the final lens and project the laser onto a surface and photograph the spot (you actually can do this) you will find that the RF laser has a very controlled uniformly illuminated spot and the tube unit spot will be sort of crude in comparison. Again, it is what justifies the extra cost. After going through a final lens, the RF beam is very nicely focused, and the tube beam is sort of raggy. Added to the inaccuracy of the steppers, the beam is just not a accurate as a RF with servos. Also, because RFs can pulse the beam, you can cut somethings like cork and leather much more easily than with tubes that most leave a charred mess. As to life of the laser. RF tubes can run at 100% continuously. They only run at 100% power and pulse if less power is needed. Synrad says that their tubes that run continously can last 44,000 hours. Water tube lasers advertise long lives, but the reality is that most will not last 300 hours at 100% power. I know because I have run some at 100% power. Most tube manufacturers spec something like this. "PLEASE NOTE: Frequent use of high laser power settings will shorten the laser tube lifetime as follows: Low Power 10-40% = 7,000-8,000 Hours Moderate Power 40-70% = 5,000-6,500 Hours High Power 70-100% = 3,000-4,000 Hours" and that is at mostly 70%power. The tube laser manufacturers that we spec usually recommend no more thn 66% power which means that your 90 watt tube is really a 60 watt tube and the wide kerf means that you are burning 4 times more material. I am in mechanical engineering and have 20 or so years of optics off and on plus a lot of machine design. You will never come across an aerospace milling machine with steppers and you will never come across a laser in industry that is cutting highly accurate engravings with a water tube and steppers. Never. If you are cutting chunks of acrylic to an accuracy of 0.01 inches and can live with the tapered kerf go with the tubes. I love the low cost of tubes and spec them for schools and manufacturing. China has millions of them cheaply churning out tons of Chinese things. I will stay out of this now, but there really is a difference besides cost between RF and water tube. d
Currently I'm waiting on delivery of a GWeike RF 38 W - Glowforge type desktop machine. Priced better ($4100 USD) and Lightburn compatible. The main advantage to me is air cooling to remove the need for antifreeze in my unheated Minnesota winter shop. My 1st laser so I will be curious to see how it performs. I am curious on the power input/waste aspect, what in the entire measured input wattage for each type when running.
Hi Dave The 38 watt unit is sold as a 30 watt RF source. They always deliver higher output initially so that they can degrade and still be in spec at the end of the warranty..Yes I have measured my 30 watt unit as having 38watts also., So GWeike are strething the truth a bit for marketeing purposes.This is just a compact 500x300mm bed like my Tangerine Tiger. In its standard form, RF technology was rather disappointing. There was none of the "magic" promised by the likes of Trotec and Epilog. I looked very hard for months to see if there was anything that stood it apart from glass tube technology and to be honest I didn't find any advantageous features (not with 30n watts anyway). My recent work with beam size and lenses had made me realize that any merits that RF may posess will not be apparent until the soiurce is 100 watt plus.........but that requires mega bucks Thus it sits unloved and little used other than as an experimental test bed in attempt to find ways to enhance its performance. Thus I daily use either of my two 70 watt glass tube machines. I will be interested in whether GWeike has added a beam expander to the laser outut port and if so, what magnification it is? This laser may be aur cooled but that makes it veruy noisy because there are 4 very powerfull coolong fans tha carry away the vast amounts of waste heat. If this is your first lasert then you will have nothing to compare it with. it is certainly much bettter and more flexible than a diode laser . From all that I can see this looks like a licenced variant of the Glowforge , but cheaper. The description "3D LaserPrinter" for this kit is exactly how the Glowforge was marketed. A totally misleading description. RF technology is managed by a control system called PWM. This is quite difficult for most people tounderstand how this whole technology works thus many of the controlls I have will be hidden inside preset sliders or menus. I will always be here to help if you shout but you may not be able to do the things I can do with my "raw" system. Best wishes in your new adventure Russ
Don't give up on the dream just yet because I'm sure it will be good at a few things, but are those few things worth lusting after such an expensive machine? You must remember that my tube is only 20watts and although the glossy hype and demos may tempt to buy a lower power , less eye-wateringly expensive machine, I think there will be little benefit (performance wise) over a glass tube machine. Yes the glass tube machine response time will always be slower when it comes to high speed engraving and as the next video in my series shows , that switching time is vital to fast crisp engraving. but without power ( and that rises exponentially with an RF tube) I cannot at present see anything that makes this technology appealing. I can have 10 Chinese machines, many tube replacements of tubes and significantly more production and flexibility with just TWO cheap machines.. As I will continually demonstrate, linear speed does not get you a faster cycle time on its own. it needs amazing acceleration factors to keep the overrun to almost zero So claims of 2 and 3m/s speed may be possible (they look great on the spec sheet) but what can you do with it if you don't have the power and if it results in slower cycle times. Sadly we never hear the whole story when we watch carefully edited videos. A t present ii have only looked at the fixed amplitude/ varying duty cycle PWM mode of operating. The Ruida controller offers alternatives which I will be investigating in future. I cannot say how other controller work other than to emphasize that there is no magic which amplifies power. If I have a 20 watt tube the ONLY time I am going to get this 20 watts is if I set the machine to 100% duty cycle, so that it effectively emulates a glass tube .....but with lightning fast responses. ANY other mode will reduce that power.. If you can afford a 60 or 80 watt tube then yes, total control of the PWM signal is necessary to control power. I can only demonstrate what the Ruida controller does so do not assume that the expensive machine controllers act exactly the same way. I think this will become clearer when I investigate amplitude control that I think I can access for engraving. Best wishes Russ
@@SarbarMultimedia Thanks for the in depth reply, i used to work in a school & used a lotus laser systems 30w Rf machine for the last 5 years, nice bit of kit & we did some fantastic work with it, Last year it started to fall down as it was about 10 years old, then the service provider took the support contract away from the manufacturer & gave it to a bunch of idiots 300 miles away, that was the end of that!
Hi Yes.....and No. Thr reason glass tubes are relativly slow at doing photo engraving is that dithereing an image creates black and white pixels. Black pixels use whatever max power you set and white pixels require zero power. . Zero power means the tube switches off. Every time the tube switches off it takes at least 1ms to switch the power back on. 1ms may sound like a short time but when you are trying to use a 254 ppi image, each pixel is 0.1mm wide. So that is 10pixels per mm. I I chose to run at 200mm/s then I will be trying to reproduce 2000pixels per second The response time of the power supplis 1000pixels per second max so every time I switch off I am going to lose the next pixel (at least). There is no such delay with an RF tube, the switching is instant(ish)and I can run at 1000mm/s without pixel loss. So my thoughts at this time was to see if I could prevent the glass tube switching off during photo engraving so that I could bypass this natural barrier. I had an idea which I test crudely on a glass tube machine with limited success. To get you right up to date I recently started to investigate this issue again with a more scientific approach to see why my method did not produce the amazing results I had anticipated. This video explains my method and why it failed. The method was logical but the 40 year old power supply design was just not up to the job. see ua-cam.com/video/_13bnvpdBoA/v-deo.html Best wishes Russ
@@SarbarMultimedia thank you very much for your reply. Your video is very educational. Sounds like RF is the way to go if you want to do high speed engraving but is it difficult to get a consistent beam strength across the size of the bed? Thank you
@@icdjpr The fact that 95% the time I use my glass tube machines tells you a lot about what I think of the RF machine. Yes it has some positive points but nothing that makes me fall in love with it. It has been a great piece of comparative experimental technology but...... The problem with a beam that changes diameter the further it gets away from source is a problem that I have not solved satisfactorily. The conventional way is to fit a beam expander. See www.cloudraylaser.com/products/cloudray-znse-co2-beam-expander?_pos=2&_sid=ad11ca2db&_ss=r I have tried them all and the X2 is the best of a dodgy bunch of kit. These are designed for laser machines because they have special ZnSe lenses. However they are designed with conventional lens theory principles for telescopes invented by Gallileo. Hmmm, I wonder how much he knew about laser beams.? See www.edmundoptics.eu/knowledge-center/application-notes/lasers/beam-expanders/?gclid=Cj0KCQiAxbefBhDfARIsAL4XLRqOeVlvFBdwjcckHnC_5EMmB6teT-sYWg1gSysmXyEd0mWt65_R2u8aAuQxEALw_wcB The beam expansion issue becomes an issue if you have a glass tube in a large machine.The 2 to 3mm per meter beam growth has a noticeable effect on cutting performance With an RF beam you are speaking of 7 to 8mm/m beam growth. So, even on my 500x300 machine the cutting performance difference is noticeable without and expander and with the beam expander the difference is less but it degrades cutting performance across the whole bed because the beam has to be expanded to make it parallel (ish). At 30 watts, It will only ever be an engraving machine. Provided you use a compound lens and have the settings right, it is great for photo engraving and with a 2 or 2.5" lens performs well at 3D engraving. It is possible to overcome both of these issues if you wish to spend mega bucks www.coherent.com/content/dam/coherent/site/en/resources/datasheet/lasers/COHR_DiamondJ-2_DS_0518_2.pdf This is 150 watts (cutting no problem) with a 2mm/m beam expansion and thus solves solves the problem....but dont ask the price!!! You will be able to buy morer that TEN glass 150 watt tubes for the same price and a glass 100 wat tube still beats a 150 watt RF at cutting speeds You need to think carefully about the choice because the glass tube can do the samer photo engraving job but slower and can then change its character and will cut 20mm acrylic with just 80 watts. The limitation with the glass tube is the HV power supply as I demontrated in the video link I sent. If this data is true for al lHV power supplies I will,soon find out because I have recently received two different power supplies to evaluate . I suspect they will all be similar .....but I dream they may be more responsive. Thats another future video Best wishes Russ
@@SarbarMultimedia my son and I are rebuilding a 120w co2 48"x48" machine right and your videos are priceless and wanted to and wanted to know your thoughts on going to a bigger or smaller tube we are wanting to do engraving and cutting and would love to have a 150w tube and as attractive as that sounds for cutting do you lose the edge on engraving? And we are changing it to close loop steppers 2nm and a 3nm it has 3:1 reduction on both drives and we have seen a few machines with direct drive and was wondering what would be best. Thank you very much for your time
@@icdjpr Hi Team 48X48 inches is quite a large machine. Cutting performance drops off with distance from the laser source. because of beam expansion at the rate of about 3mm/m Your beam will vary from about 0.3 to 3m so at the extreme corner the beam could be 15mm diameter. because a typical tube of that size will emit a 6 or 7mm diameter beam. The most efficient design for a large bed machine is to remove the "flying" beam from one axis by mounting the tube onto the gantry. In that way you limit the beam to just 1,5m in the X axis only. and beam setting is so much simpler. I50 watts is great for cutting faster and thicker and will be fine for most types of engraving including 3D work Photo engtaving may be off the cards because that normally involves using the preionization operating zone at about 4mA (ish) ALL tubes have this preionization zone but I dont kniw how controllable and powerful it will be for a 150 watt tube. This size machine is never going to be a greyhound because of head and gantry masses. but it will probaby scan at 500 to 600mm/s (maybe with a loy of overtravel) Direct drive is always a bit of a problem because stepper motors are very "steppy" at slow speeds. To reduce this effect astep down geat is used to drive the axes. ie the stepper motor spins 3 or 4 times fasterthan a dirct drive and thus the rotational inertia of the stepper rotor, tend to smooth out the steps. Th faster the steooer runs the bsmoother it becomes.. However you then have a bit of a balancing act to perform . Stepper motors do not run very fast (600 to 800 rpm) and as they get faster the torque rating drops off quickly. The down gearing helps to offset this loss of torque. but the inertia of the extra intermadiate pulleys reduces the ability to accelerate rapidly. It also has an effect on another very overlooked problem ...resonance se this short video ua-cam.com/video/yVbzm41tcy4/v-deo.html Good luck with your venture . It will be an exciting learing journer both with engineering and ultimately laser technology. If you haven't been there yet you might like to look at this series of videos laseruser.com/the-concise-rdworks-learning-lab-menu/ Best wishes Russ
The speed of switching is actually a huge problem, at least to me. I could make products twice faster if my tube was able to do that, I am very interested if you came up with that different control solution or not (controlling CO2 tube with PWM)? This would be the best of both worlds if it is possible to make that work. This way I could just install a servo motor on my X axis and engrave with 2000mm/s! :)
Hi Vlad As I am answering this comment, I am in my workshop investigating the switching speed of a CO2 glass tube laser. I have already done work on this subject in ua-cam.com/video/_13bnvpdBoA/v-deo.html. I basically discovered that the response time of MY power supply was VERY slow.. Further research indicated that the basic design of the HV power supply is more than 40 years old and was designed for the Chinese by a Bitish professor who ran his own laser company when laser machines werre just beginning to become available outside laboratories and research institutes. As with all things Chinese, they are good at copying but not to good at innovating and updating this product. I currently have two more different style HV power supplies from other manufactureres that I am in the process of testing to see if there is any difference in the response time.. I am just setting up my equipment ,so it is too early to say anything at present. butI will be publishing a video on this subject. The PWM control of the RF and diode lasers does allow really fast swithcing speed and with my RF 30 watt laser I have achieved 800mm/s with a pictyue resolution od 254ppi. This translates to a dotting speed of 8,000 dots per second. But at this rate you are VERY material dependent and power dependent, so I think 2000mm/s is a bit of a dream for a glass tube. Best wishes Russ
27:00 "I've got a much better quality beam from a glass tube by the time I get to my lens than I have here [RF tube]" Russ just fired shots at the RF tube guys!.
I hope you realise that there is very little opinion in this video, just published data laid side by side.........something that you will not have seen done before. That I am disappointed, I suppose, is an opinion, but it is based on the fact that logically I will not be able to magically make all the RF hype come true. I will continue to test the various aspects of the technology but as I mentioned in the video, the capability of the mechanics now far exceeds the capability of the tube I possess I am sure I will be able to create near-invisible "normal" engravings at 1000mm/s on soft card , Why? because there is no magic in 20 watts of RF created laser light. ....even at 100% power it is still only 20 watts. Best wishes Russ
Russ, Thank you for this. I have a diy laser lathe setup using a 100w RECI tube. My engraving speed is severely bottlenecked by the switching speed of the tube. I am eagerly looking forward to the installment where you discuss potentially being able to switch a glass tube with similar speed to an RF system that you mention around 44:30. Any direction on how this would be achieved that you could preview for us?
Hi Jonas Can I ask you to watch this video to start with to see how the OUTPUT DIRECT switch works. ua-cam.com/video/pwOY-U6BB8o/v-deo.html There was a lesson in this video that I failed to see and it is relevant to your question.. Whenever the tube switches OFF it takes the response time to switch back ON (maybe 0.5ms). With an RF tube this is microseconds or less. So the problem is how do we stop the glass tube from switching ON and OFF during a scan..... I know that sounds a stupid question because logically it must switch on and off to produce a burn. OK so if you have watched the video I cite above , you will see how the machine treats grayscale engraving. It varies current flow through the tube, theoretically (because of the physics) at microsend response times. .........unless it sees white 255, whereupon it switches the tube OFF and then requires a millisecond timescale to turn it back ON. Watch this next video to see how it is possible to make sure the machine never turns off. . ua-cam.com/video/Iswn-R_mbck/v-deo.html The example I use is photo engraving because that is most demanding but this technique can be used for any BITMAP image. It will not work with vector images or text. you will have to convert them to a bitmao so that you can further make them into this special grayscale format. Having put you through that interesting learning exercise , I somehow feel your problem is not going to be solved by this approach........at the moment. Let me explain further. You mention you have a 100 watt Reci tube (I assume a W2?) That's rather worrying because I and lots of other correspondents from around the world have experienced problems similar to yours with Reci tubes. I suggest you add your disguised email address to another comment (jonasdot conception======AT ****gmaildotcom) so that we can exchange pictures and more information. I will reply and also delete your comment from public view. Best wishes Russ
@@SarbarMultimedia Thanks so much. I do not know if I have a problem with my tube, or if my expectation's are off. The first video you link is very helpful as an example on how to structure my experimentation and measurements. My takeaway from the second video is that by using a gray instead of white the controller pushes a very low power signal that is not enough to mark, but enough to keep the charge in the laser power supply that you would be able to significantly reduce the time it take to ramp up laser power when compared to a fully off position. Anyway I would love to talk shop if your willing. I submitted a previous comment with my disguised email. I'll send another since I did not see it show up.
@@Joncon00 Hi Jonas Yes it didn't show up UA-cam is VERY inconsistent. About 5% of all traffic gets sent to a parallel universe. VERY annoying when it's a long complex answer to a comment. Sometimes your comment will make it to the copy they send to my email and yet it still doesn't appear as a comment. Please try again Best wishes Russ
@@SarbarMultimedia It seems that my comments with disguised contacts are being removed. Its my full name with no spaces using google's email. maybe that will get through.
Hi There were no positive nor negative expectations from Mr Cloudray. He gave me this RF tube because he was finding more Chinese companies were beginning to fit these to machines. He is a wholesale distributor of equipment but he likes to be technically aware of the products he is selling. He does not have facilities nor time to do the deep diving into the technology in the way that I do. He is keen to give his customers good and truthful advice and so far the only "truths" out there are the hyped up benefits being pushed by the "big boys". I have skepticism genetically engineered into my DNA but even I was expecting to find something magical about RF technology. . Hmmmm.... sadly no . It is just an expensive way to create a CO2 laser beam. The PWM means of controlling it seems so simple, but scratch the surface and below you will find a VERY complex relationship between frequency, duty cycle and linear speed. The big companies have written control softwares that hide these complexities away from users. You do not have to understand the technology to use one of the expensive products. No, all you need to do is be able to select predetermined parameters from menus. Thus the technology has been "black boxed" and made user friendly. Selling an RF tube and a Ruida controller is not a good idea and I think just the cost will prevent it ever becoming a serious contender in the small business/hobby market. In summary I think your reading is incorrect and that my "telling it like it is" will prevent Mr Cloudray from burning his fingers with large stock investment. He will also be cautious with his advice to potential customers. However, thanks for the comment because others have also commented that this will not go down well with Cloudray. This allows me to explain that there are positives that arise from my negativity and truthful comparisons. I now have the RF unit and despite my disappointment, I will continue to dig deep to understand the intricate ways that frequency, PWM, and duty cycle interact with different materials. . Best wishes Russ
@@SarbarMultimedia ็Hi, thanks for the detailed explanation of the situation. Would you mind giving me a verdict on whether or not I can use my newly ordered 3050 China blue machine with Ruida controller to make proper rubber stamps provided that I am willing to immediately swap out the K H tube and replace it with something more standardise and also willing to run all my jobs at slower speeds (not exceeding 100-140 mm/s) ? I often run into small fonts as miniscule as 4-5 pt on my customer's stamps and if changing out the tube and running the production at slower speed will not help in this scenario, then I can begin to save up as there's a very attractive offer from a "Rayther" brand engraver with size 6040 and 40watts RF tube machine costing $5,500 including shipping (not sure about the quality of their RF tubes) Other more reputable factories such as Aeon or Thunder are giving similar specs offer at double the price. I asked you this again because as I come back to watch your series, it seems that you made a conclusion that RF units are great at engraving detailed drawings at highspeed but I could still not conclude whether running the glass tubes at slower speed would've solve my problem in a "poor man's" way or not :D Thank you again, Anand
@@avcomth I have sent samples to you done on a glass tube machine so that you can see what is possible. If you really want to try the RF route then I can see what's possible on my 30 watt RF. The problem is power rather than speed. To cut depth (about 1mm) in one pass requires a certain power exposure time for the material to erode/vapourise Lets say that you can only achieve the 1mm depth if you run at 30 watts and 100mm/s.. If you had 60 watts than you could do the same erosion at 200mm/s. The switching is so instant that linear speed is not the limiting factor. It will always be power. With an RF system the power costs about $800 per 10 watts Best wishes Russ
I am at a point when I have to decide myself and in research between the two, RF and Glass. the quotes I had for RF were eye watering. Way outside my reach unless reconditioning used unit, and even that is a difficult spend. So far my findings are quite the opposite, with regards to beam quality and energy efficiency. disregarding the price of course. I wonder why you have not mentioned power density and spot size when talking about divergence? and Where will a 6mm beam be after a 1m in both cases? at 3mRAD for glass, and I would like to see something other than ebay spec sheet on divergence.... even RECI don't show it in their datasheets. same with m^2 being 1.1 Why not mention power stability when talking about control signals? Where did you get 9kV figure at 14mA from? is it not closer to 15-18kV at 24mA ? and where did the 3mRAD come from? Machine I am working with is 2.55mx1.4m cutting area. I think It would be also fair to include the power used by industrial chiller used to cool the glass tube Vs 12v or 24v fan on the RF tube.
Hi Dave Thanks for your very interesting questions and comments. I have been using glass tube laser of many types for the past 6 years and have two of my own. I do not run any sort of business with them, they are purely tools for me to decode the laser technology and keep my two remaining grey cells exercised during retirement. I have always lusted after an RF machine because I have seen them at exhibitions and watched quite a few videos. There was some sort of magic in the RF technology that made these machines so desirable . The hype , the claims, the disdain for the rubbish Chinese glass tube technology continually kept nagging at me. I eventually had the opportunity to find out for myself about this miraculous technology when Cloudray offered me a free 30 watt RF tube to evaluate. I bought a basic machine and converted it to the Tangerine Tiger. I then set about understanding how the tube and the PWM control technology worked. and how it's performance compared with the rubbish glass tube technology that I had invested so much time in learning. After 21 exploratory/learning session with the machine, I failed to find the magic I was anticipating . I found nothing but smoke and mirrors and the machine has remained switched off for the last 9 months. To your specific points. Convergence and spot size are characteristics of a lens and have nothing to do with the source of manufacturer's Low power glass tubes are short and therefore the voltage required to ionize the very short column of nitrogen gets less. Once triggered, the voltage to sustain the ionized beam drops of to a significantly lower value. Even with my longer 70 watt tube, when I turn the power down to 20 watts it only pulls 12 mA Your voltages and current flows exceed those for my 70 watt tube ( see the SPT C70 specification.) You can see typical low power specs if you look at the C25 tube. Wow, that is a big machine . That a beam length variation of 4m. A glass tube of any sort is going to struggle over that area because of beam divergence . That will be a huge loss of cutting power from back to diagonal front corner. I have seen this problem on smaller machines than yours and there is a good example of this that I show at 27:10 in ua-cam.com/video/z8sNPtIIXZ4/v-deo.html To achieve a uniform size beam you will have to consider a beam expander and I must be honest and say I have never seen a beam expander used with a glass tube .....I think because people don't realize there is a problem. The massive beam expansion with an RF tube makes it a mandatory fitment and there are lots of choices. I can ask my local machine builder if there is a solution he can recommend Best wishes Russ
@@SarbarMultimedia Thank you for a quick reply :) Well caught on the size of table and this is precisely why I have started looking at RF, beam expander and possibly a phase retarder. (So far I think I cannot use the latter with glass, due to random polarisation but I am still researching that) The objective is to have a full 8x4 sheet on the table. I agree, convergence and spot size are characteristics of the lens, I should have explained myself better, I was talking about beam diameter as it exits the tube which is safe to say is 2.5-3 times larger in Glass tubes. That plus beam divergence (my desk based research suggests better in RF) and we start to go beyond standard small mirrors. As for energy efficiency, many of them come with just a fan for a 100W RF tube, whereas a 100W glass tube will need a chiller. It's very interesting to see that you have found beam quality better in glass tubes, this is a pause for me to research a bit more. The gantry is not complete yet and I am only just about to buy the tube.. This is my first machine and I hope I will not get defeated to half the bed size :D Your videos are helpful and thank you for making them!
@@davedavidson4215 Hi Dave I know the machine builders I have close contact with have made large format machines, but I seem to recall that they mount the tube on the gantry and set the gantry across the 4 ft span That way the beam length change is only 4 ft and glass tube beam divergence is tolerable without any correction. Just a thought if your design/build will allow for such a configuration. Best wishes Russ
@@SarbarMultimedia Thank you, all and any input will be very helpful. My build will allow for that and I have a separate rail to make it happen but a thought of high voltage even at those currents and water lines on a moving gantry made me a bit uncomfortable and I will keep it as a last line of defence. If I go glass then it will be most likely a 130W tube, so the change there will be 8ft as I have to place it on the long X gantry in my case.. exciting times!
I've started seen 100W-150W RF laser tubes go for 7000 to 8000 USD on Alibaba, the commercial brother of aliexpress including RECI branded. I wonder if the investment is worth it. I was really hoping you could take the RUIDA controller to its limits as that's where I believe the limitations will be in the long run. I've been able to photoengrave at 500 mm/s on wood with my glass tube with lets say 90% the fidelity I achieve at 200 mm/s, but past this the results are not reliable, I get all sorts of artifacts and erratic behaviour (memory related) unless I use something like 100 DPI, so even going with a 100W RF tube would still have its limits, I know you are going to be able to figure out how to solve those issues. Best regards.
You are correct . it should be capital M for Mega rather than lower case m for milli. Thanks for spotting the detail....so, I didn't send you to sleep!! Best wishes Russ
Real advantages of RF system around 35:00. In the end, doesn't seem way better for the price paid.. I have a 100W RF CO2 laser on an old machine (2009) I bought recently in an industrial auction. It was working great at first for few times. However, now it doesn't work anymore (stays always ON or OFF while moving in the program), I tried to troubleshoot with Laser manufacturer (ROFIN) but they told me I have to change a module costing about 7.5K$USD... Furthermore, they can't guaranteed it will work and the warranty will be only on the module itself and nothing else. I called few people to come see what's the problem but we never really figure it out. I am now starting to retrofit the whole machine (changing motion controller and switching to much cheaper tube). Hopefully the retrofit will be a success. I am waiting for the controller right now.
Hi You will not be the first. There is a guy in the UK that is regularly "upgrading" expensive RF machines to glass tubes. The one great thing about those machines is the mechanicals. Nice bearings and proper DC servos (usually with rotary encoders.) Team those amazing benefits with glass tube technology and you will have a REAL dream machine. Because of the significan beam divergence of RF "tubes" they MUST be fitted with a beam expander to almost correct this. However a beam expander is great for engraving but it limits the peak intensity of the beam (makes it blunt) and thus hobbles it for cutting. With just an 80 watt glass tube (make sure it is A grade because there is a LOT of junk out there for the unwary to buy) you will already be way ahead for cutting ability. All best wishes for the success of your new project. Please report back when you are up and running .. Russ
@@russsadler3471 hi Russ, thanks for that. You said I will need to change my mirror and nozzle lens system as well ? How to choose the good lens ? I am thinking about the "best" laser tube company said on the web: RECI, is it right ? I already bought few stuff from lightobject (california) instead of cloudlaser (china) The old RF I had is a ROFIN OEM10 iX. I was thinking about trying to make the laser works with the new motion controller... maybe theres still life left inside. You are right about the mechanics, I paid a bit too high in auction but the mechanical aspect is no way close to Chinese machine, it was made in Canada (alphalaser-flx). Mine is not servos nor with encoders but stepper motor (drivers and motors are Parker so they must be pretty decent) but HIWIN bearing rails, special composite type anti-backlash spring leadscrew and adjustable Z axis. Wish to add rotary axis later on too. When I bought it, I thought myself is even if the laser is bs, I will convert or use the mechanical on something else
@@russsadler3471 i made a post on CNC zone few months ago (same username as here) but it seems YT is blocking me to post the URL... i don't understand why
@@QuebecoisSti Hi I am not a Reci lover. I have helped install/ replace 6 different Reci tubes for friends and local businesses.. There was nothing remarkable about the tubes except A) set up to Reci specs they all ran at least 10% lower power output than specified and B) they were all at least twice the price of an equivalent tube from EFR or SPT . Yes, they are nicely engineered but I would never personally buy one. The other disturbing thing about Reci is that they are moving their final test failures into the open market for sellers to honestly sell as "genuine" Reci tubes but failing to tell you that these are B grade and do not carry a Reci warranty. Reci are not alone in this sharp practice but most others are retested and relabelled with the sellers label see. ua-cam.com/video/z8sNPtIIXZ4/v-deo.html I and others have had less than satisfactory experiences with Lightobject so you will have to make your own mind up on that issue. I am very sure that the DC servo drives you have will accept positional signals from a Ruida controller so you will not have to make major changes to the control system. Go tothe Cloudray website and all the Ruida controller manuals are there for download. I would recommend the RDC6445. There is the free RDWorks software dedicated to Ruida controllers or a rapidly upcoming piece of software that you should look at called Lightburn. I can recommend lenses but you may wish o fit a different head to your machine for a much cheaper and more flxible set of lens and nozzle options Add your disguised email to another comment (johndot smith=====at geeeemail=====dot com) and I will reply so that you can send a few pictures. I will delete your comment Best wishes Russ
@@SarbarMultimedia i am getting hard time being able to comment here. Something is triggered and deleting it... I was trying to find an alternative store of cloudlaser and thats why i choosed lightobject. Hopefully it will be ok... i was supposed to get my stuff last friday but it seems USPS is chaotic before christmas time... i have tracking infos but they arent updated so often. I already ordered a Trocen AWC 7824 mostly because it support dual motor drive on Y-Axis (which is how my machine is built). I tried to find infos on dual motor drive on Ruida controllers which seems to be the loved and standard one around on the web but it seems it wasn't working. The 7824 is LightBurn compatible according to what they said. 333mmmA1llll below
Clever and interesting and very informative to anyone with the ability to retain all the information russ has given (but) unfortunately for me even though I love his videos (I can’t retain) information like the majority of his viewers due to my epilepsy but tough there is people who have worse disabilities than me : resulting in the fact I’ve still got a brand new K40 I’ve modified now safe to be used and a eleksmaker desktop I haven’t even used either because I cannot memorize every move needed on the computer screen - so my alternative is to get the wife away from custom personalised slate door signs ( hence why I wanted a k40 to laser engrave them along with her way) and her personalised Pajamas she makes although my chances are low at the moment as the amount of orders she’s got ( if anyone is interested in her items) you’ll see the on Facebook under the name ( the little company). Anyway that’s my COVID lockdown rant done and I can’t wait for our next session of these fascinating videos ( without my little rant. Stay safe everyone and goodbye 👋
I was under the impression I was missing out not having one of the expensive RF lasers. Now my glass tube laser looks much better once I finish it :-). Thanks again.
Hi Russ
That was quite an interesting comparison.
We are here at the entry level glass tube, and always looking longingly at the supposedly superior RF lasers.
You have shown us we need to better exploit what we have, you have me intrigued with your upcoming instalment!
Cheers
Ralph
I bought a laser from Epilog which had numerous problems and caused me many years of grief. Now I have a Thunder laser and it has been a far more enjoyable experience so far. Thanks for the videos Russ.
Another great video. Proving in this case less is more. And a rear bomb shell at the end. Can't wait to see what you come up with. Exciting times ahead
This video is gold! Thank you!!
Another interesting video Russ.
My metal tube, which is a 30W, is no where near to your 500+W input. My entire system which includes an extraction fan, laser, Galvo's and PC all draws less that 600W at full power.
My metal tube has a power supply rated at 10A 48V 480W. On average it draws about 5Amps which is about 240Watts. Using an oscilloscope with a shunt resistor to measure the current, it spikes at about 10A only at the very beginning of the pulse cycle and then drops down to about 3.5Amps. I can do hour long engravings and only feel a small amount of warmth on the tube, and the ambient air temperature does not noticeably increase, which would not be the case if 500+W of heat where being pumped into the air.
Your efficiency chart vs my data are very different. My CO2 is listed as having an efficiently of 12%, which means only 12% of the input power is converted to light energy, the remaining 88% is heat. That is a factor of 8 and if you do that numbers, my 30W should input at 250W, which is pretty close.
As my CO2 marking machine is a Galvo (like your lotus fiber, only a CO2) and is only used for engraving, I use a beam expander to bring it up to 12mm. Then it focuses down to a nice small point. The focus point is critical on this machine, but I can engrave at 508DPI (0.05mm dot size) with exceptional quality images. Another advantage of the galvo when used with a high speed RF is you can use what is called drill mode, and produce dots, not lines, but this is a little slower. My 30W is rated up to 100kHz. Which i need when engraving at 508DPI at 3000mm/s, which required 75,000 dots to be burnt per second, so I set it at 75kHz. This type of speed on not possible on a glass tube.
Another big advantage of the RF laser over a glass for engravers, at least for my tube, is that my tube is rated to maintain >90% of it's output power over it's 40,000 hour life. Glass tubes are usually only rated for 10,000 hours and the power will drop off as they get older. I have seen this happen over the years, and while technically the glass tube laser still worked, the power output had decreased enough that the engravings where getting faint. No such problems with the Metal RF so far.
I am trying to find the info, but I had read that the M.2 beam quality of a glass tube is also affected by it's power. As you reduce the current to the tube, the more unstable the beam becomes. RFs do not suffer from this. Some specs will show the M.2 quality at a given power level for this reason.
I 100% agree that glass tubes are better for cutters, but for purpose built engraving/marking machines, the much faster switching speed and consistent beam quality of an RF is a winner. I have both Glass and RF, used for completely different purposes.
Hi John
As always, your expertise is a valuable contribution to extending my horizons. Your detailed information is absolutely brilliant and only goes to fine tune the basic comparison I made. Photo engraving is one of the weakest aspects of the technology but I suspect It will excel at normal engraving and 3D engraving but be pretty poor at cutting. The fact that you have dedicated cutting and engraving machines tends to confirm that expectation. I will never be able to drag the existing motors/mechanics up to 3000 mm/s but I hope to make a few more small changes that will allow me to reach 1,500mm/s and not have massive overruns. I have two goals for this project. One is to find the extreme mechanical performance envelope of that very basic piece of cheap engineering and secondly to examine and understand what is so special about the RF laser that it justifies the premium price. I would estimate that more than 99% of people with this RF equipment have bought it to use and trusted the "experts" to created an "amazing" technology. They are not going to spend time digging into the minutia of how science is being employed, but understanding this detail is what fascinates me.
The drill function of the galvo system is truly wonderful and I employed it to great effect when engraving slate. Sadly Lotus have "un-loaned" the fiber machine because they had an urgent sale they had to fulfill..... but it was a great learning opportunity.
Thanks again for sharing your years of professional experience and I always appreciate your insightful comments.
Best wishes
Russ
rf lasers are great for very fine and fast engraving. they operate at a higher frequency compared to glass. We have both types, and also a dual RF 60watt + 60Watt Universal, with beam combiner. just one tube is fired for fine engraving, at fast speed, and high pulse rate - and for cutting 25mm acrylic in one pass using both rf units on full power.
There is no comparison an RF Laser will out shine a Tube in the long run, give cleaner straight cuts, razor sharp engraving, you really have to experience the two to know the difference. I want to upgrade my Chinese asap and I never knew it was possible until I found your channel
Hi Farouqi
You are right to say there is no comparison BUT it depends on what your needs are. The one and only advantage I can see for RF technology so far is the instant switching speed that allows crisp engraved images at high speed PROVIDED you have the power to keep up with the speed. There is no miracle in RF technology it is the same CO2 laser beam, the same lenses, but the tube is configured to always sit in standby mode to give this instant switching capability.. As I have already discovered, it is not very good at the one goal I had for the machine, fast photo engraving. Even with my compound lens system the RF cannot match the quality I achieve on a glass tube machine. see ua-cam.com/video/ATu-7EGZGMA/v-deo.html
For cutting there is only one thing required and that is power. It will be an eye-watering cost to upgrade with a 80 or 100 watt unit.
With the 20 watts available to me I will not be doing much cutting or even 3D engraving. If I can cut 3mm material of any sort I will consider myself lucky. That is in the next session that I will do some cutting.
I am not a salesman or a teacher, I am just a student who wants to understand the technology. Like so many other people, I have listened to all the marketing hype around the expensive RF machines and wondered exactly what the magic was. I have watched many carefully edited slick demonstration videos and spotted all sorts of technical issues so it was with a serous enthusiasm for the technology that I have embarked on this learning journey. I trained as production engineer and have spent millions on equipment purchases for big companies I worked for. As a value for money investment I could never recommend this technology based on what I know so far. If you run a niche engraving business you may consider it BRIEFLY but to be honest a much better investment to do CO2 engraving, would be an RF unit strapped to a Galvo head. Much cheaper, faster and more compact. If you specialize in cutting then speed is of no value because cutting requires power and you can only go as fast as your power allows , maybe 20 or 30mm/s . What is the point of high speed servos and hideously expensive laser source?
I am enjoying my trip into the RF world but on the basis of what I am finding so far you maybe the only one to follow my lead.
Many thanks for your comment
Best wishes
Russ
I’ve run 60 and 100 watt BOSS Laser glass tube machines for 6 years now with wonderful results (and company service) but always wondered what I might be missing from an RF machine. This video breaks down amazingly why I shouldn’t have even given it a second thought. I’ve recommended your videos for every new laser owner I’ve spoken to since discovering them myself.
Russ, have you considered making a square shaped window that will attach below the nozzle to artificially force a square beam shape and achieve a square pixel? By shaving the edges of the round beam it may be possible to get a more consistent power level within the area of the “pixel”.
This is another great video Russ. The way that you explain things in such a clear to understand manner is excellent. It should be noted that not all RF lasers are the same, however, most decent DC lasers have very similar performance specs. Therefore, the comparison for some of the tech specs very much depends on which RF you compare to which DC. As you point-out, the main reason for investing in an RF is the rise/fall time, typically 75us for a decent metal laser with integrated RF. In industry other factors such as integration space, movement of the laser source, etc also dictate an RF must be used. RF lasers will perform better at very low duty cycles and RF lasers will have better power stability, assuming cooling is working well. Some RF lasers can be pulsed too so that Peak Power exceeds Average Power usually by a factor of x3 while CW lasers of RF or DC type will have a peak power roughly the same as max average power. Some of the Pulsed RF lasers out there have a much better M2 too. For example, the Coherent J2 will be 2mrad. In a plotter format machine it's hard to justify the cost/benefit of using an RF laser, which is why virtually all of the
Hi Dean
Another machine? Another wavelength? Sounds interesting. I had better hustle on with my RF project!!!
This project is specifically aimed at making a fast RF engraving machine by joining together a few low cost Chinese major components that other hobbyists can easily replicate for themselves. My comparison specifically excluded the specialist tubes that deliver high power pulses and/or that have very low divergence similar to glass tubes.. These tubes are beyond the budget of even enthusiastic hobbyists who may spend between $6K and $8K, to build their own 40 to 60 watt version. I have many correspondents that lust after one of those top brand RF machines. The marketing hype and snake oil salesmen that appear in their dodgy videos, seem to work on the less cynical part of the population that see it as a "must have" for their workshop. I'm sure you know that cynicism is encoded into my DNA , so despite wondering if there is any real "magic" in this technology , my goal was to sort the facts from myth and either justify or cure the longinging of those many correspondents. At the same time, secretly, I was really hoping to find some magic that was going to make 20 watts perform out of it's skin (like the 20 watt fiber laser)
Although I intend looking in depth at normal engraving, 3D engraving, grayscale photo replication and cutting. I started this project with the rather demanding photo engraving process. It afforded me the opportunity to examine how and what signals the Ruida controller delivered to the tube and to see just what sort of effect ultra fast switching had on various common materials. When I saw how the PWM was working, I also imagined that a short duty cycle at the right frequency to match resolution and speed would result in nice dots., Im fact , 20 watts made zero impact. When I did manage to get enough colour/penetration, the switching speed was so fast that it turned the beam on and off exactly on the edges of an individual pixel. Can't complain about response speed BUT it left half a dot before and half a dot after resulting in a 2 pixel burn for a 1 pixel signal. This was VERY bad news for diffusion (Floyd Steinberg) dithered images. and explains why all the big companies use the much cruder half tone screen method. My next video investigates this method and suggests a much neater method I have devised to achieve more photo realistic results without that pencil sketched cartoon look.
Thanks for your valuable facts regarding the process from a " top end" industrial perspective. I can see that various aspects, like no dangerous high voltages. maybe better output stability and predictable response speed are factors that make this process attractive where the high cost can be justified, It seems that you are in effect predicting what I already am beginning to feel about this project ......... that this is not a jack of all trades hobbyist technology .
Best regards
Russ
@@SarbarMultimedia RF or DC is very application specific. Since the majority of CO2 lasers
You got me laughing hard at 25:22
All I can say is that I am relieved that I did not completely wasted my money in a glass tube machine (it could have been better, but also it could be worse :P). Yet another master class, Russ. Thanks for sharing.
I have had two of each type of laser, glass tube and RF. The advantage of glass tubes is cost. You can have about 5 glass tube units cutting out bird houses for the price of one RF unit. The advantages of the expensive RF units are first kerf size. Glass tubes are usually about 0.25 mm. RF units are about 0.07 mm. the kerf size is 28% of the glass tube. This means that the beam is concentrated 3.5 as dense. My 30 watt RF cuts slightly faster than my 90 watt glass and with a much finer cut. Another advantage of the expensive RF units is that they usually have servo motors in lieu of steppers. Servos are much more accurate, smoother and move much faster. Because the kerf is so fine, RF units are only burning a slot 28% as large as the glass tubes and produce much less smoke to dirty the work piece.
Last, RF tubes can produce full power without affecting tube life. A 30 watt RF can produce a continuous 30 watts. A glass tube us recommended to not exceed 70% power. So a glass tube 90 watt unit is limited to 63 watts. A RF unit can also go down to 1% power with no problems. Most glass tubes will not fire at much less than 5 or 10% power. If you are cutting or engraving fine paper of thin veneers, the RF tubes work much better.
If expensive RF laser machines did not have these advantages, no one would buy them.
Hi Dennis
Since this video 2 years ago I have done a lot more experimental work with lenses and laser beams. I have demonstrated that there is a strange relationship between the beam size, intensity profile and watts entering a lens and what gets focused into a destructive "spot" of energy. Your assumption about energy density is based on the belief that the beam. is like a stage spotlight and is of uniform brightness (intensity) when it hits the material. In actuality the intensity profile at the focused spot is not even a amplified replication of what enters the lens. I have spent the last 4 years on and off trying to understand how it is possible for this to happen when everything we are taught about lenses says it's logically impossible. See this 30 sec video ua-cam.com/video/vTEAm-01E1Q/v-deo.html
Yout kerf width observation my be your experience but it has nothing to do with the source of the laser beam. It is entirely dependent on the lense type, the lens material, the focal length of the lens , the orientation of the lens and most importantly the diameter of the beam.. All my videos of me exploring these factors are on you tube if you care tto watch grass grow..
The fact that your 90 watt tube cannot cut as well as your 30 watt RF, is iindicative of poor beam quality from a B grade tube.. My 70 two watt glass tubes cut 3mm birch ply at 40mm/s whereas the 30 watt RF can just about get to 25mm/s.
You seem to be a bit confused about steoppers and servos. real dc servos are smoother in their action but they cannot CUT faster. Cutting speed has nothing to do with the motor speed and is all to do with the relationship between power and the necessary exposure time of the beam at the material interface to produce a cut, Speed is only a asset for high speed engraving (that's another subject).
Regardless of kerf width, "dirty" work should not happen if ALL your smoke fumes exit thre BOTTOM of the cut. Is there a problem with your air asist ?
The way the two technologies work is completely different. First you cannot control the POWER of an RF tube because it is ALWAYS working at full 30 watts The only thing you can do with an RF laser is swith it on and off for variable amounts of TIME.and that is the function of the PWM control system. You can vary the switcing frequency and the %power is changing the ON/OFF ration for every cycle. You are ALWAYS hitting the material with 30 wats. Not so with the glass tube technology You are genuinely changing the power that CONTINUOUSLY arrives at the material surface. The big difference is that the INTENSITY profile changes with power for a glass tube but remains constant for an RF tube.
You are not power limited with a glass tube, however the manufacturer does specify a maximum allowable current flow through the tube to achieve the expected life of the tube. If your tube is a specified as working 90 watts (maybe its a Reci W2?) then you can run it at about 26mA and get the 90 watts promised. However iif its a Reci W1 then the PEAK rated power is 90 watts and is a factory TEST value and not one you can ever use The W1 is rated at 75 watts and should be run at 23mA max. The %power is not directly related to watts but is all to do with the max current flow that your HV power supply can deliver..
It is true that you can run a n RF tube at 1% power but as I mentioned earlier this is not 1% power butthis is a pulsing 1% exposure time for 30 watts. Tthe RF tube has no preionization zone, and this switches on and off (for all intents and purposes) instantly. it operates completely different to a glass tube that does have a preionization zone that under certain circumstances can be VERY slow at swithing the tube on and off. It is this strange zone that is the reason why you dont see much power until a certain % power. That % power varies betwen tubes and manufactureres. BUT it is vitally important (if you understand how to find it ) for cutting veneers, card and paper at very high speed without charing, smoke or burning. see this example of card cutting using the preionization zone of a glass tube.
ua-cam.com/video/S_2NOCpACVc/v-deo.html
Your final point about buying an RF machine. The marketing is intense and conjours with the truth. I was looking for the "magic" in RF technology awhen I built this machine and was very disappointed. I have recently discovered the secret of how o do amazing high speed photo replication with the RF laser ....not the terrible cartoon engraving that Trotec and Epilog demonstrate. RF cutting ability is poor for reasons that I now fully understand unless you spend mega bucks on high powe tubes . My local plastics distributor is one of the UK's largest and does a LOT of laser cutting of acrylic up to 25mm thick. It has a Trotec RF machine for label and sign engraving but has two large glass tube machines ( 150 and 200 watts ) for fast and efficient sheet cutting. Trotec and Epilog were non-contenders in the cutting arena. So it's not just my personal experience.
Thanks for the comments.. It has allowed me to add two years of in-depth experience with both technologies to my initial comparisons. That strange relationship I mentioned earlier between laser beams (from any source) and lenses is summed up in this video and you will see thaewierd things that happen at the "so-called" focal point.
ua-cam.com/video/kddSFO-iFNM/v-deo.html
Best wishes
Russ
Having had a couple of each type, the reality is that the RF tubes cut cleaner with a much smaller kerf. You can really tell the difference when you compare the smoke produced. Little smoke from the RFs, much more smoke from the glass tubes. Might be the optics. I suppose a $5000 RF unit may be more precise than a $300 tube. If you are just cutting plastics, I would go with the much cheaper tubes and I have. I have several CNC machines, plasma, milling, laser, routing, and there is very noticeable difference in the cut quality depending on the prime mover.. The servos move with 0.0001 inch accuracies and the steppers move in 0.04 accuracies. I suppose a GCC laser not only has a smaller kerf, but also a better controlled kerf. It shows.
Software makes a huge difference. I belong to a makers group with a FSE tube 90 watt laser (the one that used to be in my shop.) It started to get a bit wonkie when rastering. The group swapped out to a Riuda controller and Lightburn. Every aspect of the FSE became better. The steppers are much smoother and better controlled. I suspect much less wobble in the path.
If you remove the final lens and project the laser onto a surface and photograph the spot (you actually can do this) you will find that the RF laser has a very controlled uniformly illuminated spot and the tube unit spot will be sort of crude in comparison. Again, it is what justifies the extra cost. After going through a final lens, the RF beam is very nicely focused, and the tube beam is sort of raggy. Added to the inaccuracy of the steppers, the beam is just not a accurate as a RF with servos.
Also, because RFs can pulse the beam, you can cut somethings like cork and leather much more easily than with tubes that most leave a charred mess.
As to life of the laser. RF tubes can run at 100% continuously. They only run at 100% power and pulse if less power is needed. Synrad says that their tubes that run continously can last 44,000 hours.
Water tube lasers advertise long lives, but the reality is that most will not last 300 hours at 100% power.
I know because I have run some at 100% power.
Most tube manufacturers spec something like this.
"PLEASE NOTE: Frequent use of high laser power settings will shorten the laser tube lifetime as follows:
Low Power 10-40% = 7,000-8,000 Hours
Moderate Power 40-70% = 5,000-6,500 Hours
High Power 70-100% = 3,000-4,000 Hours" and that is at mostly 70%power.
The tube laser manufacturers that we spec usually recommend no more thn 66% power which means that your 90 watt tube is really a 60 watt tube and the wide kerf means that you are burning 4 times more material.
I am in mechanical engineering and have 20 or so years of optics off and on plus a lot of machine design. You will never come across an aerospace milling machine with steppers and you will never come across a laser in industry that is cutting highly accurate engravings with a water tube and steppers. Never.
If you are cutting chunks of acrylic to an accuracy of 0.01 inches and can live with the tapered kerf go with the tubes.
I love the low cost of tubes and spec them for schools and manufacturing.
China has millions of them cheaply churning out tons of Chinese things.
I will stay out of this now, but there really is a difference besides cost between RF and water tube.
d
If the glass tube has less energy wastage then why does it need to be cooled constantly by water?
Currently I'm waiting on delivery of a GWeike RF 38 W - Glowforge type desktop machine. Priced better ($4100 USD) and Lightburn compatible. The main advantage to me is air cooling to remove the need for antifreeze in my unheated Minnesota winter shop. My 1st laser so I will be curious to see how it performs.
I am curious on the power input/waste aspect, what in the entire measured input wattage for each type when running.
Hi Dave
The 38 watt unit is sold as a 30 watt RF source. They always deliver higher output initially so that they can degrade and still be in spec at the end of the warranty..Yes I have measured my 30 watt unit as having 38watts also., So GWeike are strething the truth a bit for marketeing purposes.This is just a compact 500x300mm bed like my Tangerine Tiger. In its standard form, RF technology was rather disappointing. There was none of the "magic" promised by the likes of Trotec and Epilog. I looked very hard for months to see if there was anything that stood it apart from glass tube technology and to be honest I didn't find any advantageous features (not with 30n watts anyway). My recent work with beam size and lenses had made me realize that any merits that RF may posess will not be apparent until the soiurce is 100 watt plus.........but that requires mega bucks Thus it sits unloved and little used other than as an experimental test bed in attempt to find ways to enhance its performance. Thus I daily use either of my two 70 watt glass tube machines.
I will be interested in whether GWeike has added a beam expander to the laser outut port and if so, what magnification it is? This laser may be aur cooled but that makes it veruy noisy because there are 4 very powerfull coolong fans tha carry away the vast amounts of waste heat.
If this is your first lasert then you will have nothing to compare it with. it is certainly much bettter and more flexible than a diode laser . From all that I can see this looks like a licenced variant of the Glowforge , but cheaper. The description "3D LaserPrinter" for this kit is exactly how the Glowforge was marketed. A totally misleading description. RF technology is managed by a control system called PWM. This is quite difficult for most people tounderstand how this whole technology works thus many of the controlls I have will be hidden inside preset sliders or menus. I will always be here to help if you shout but you may not be able to do the things I can do with my "raw" system.
Best wishes in your new adventure
Russ
Well there i was thinking i would buy an rf machine, you just saved me a bundle!
Don't give up on the dream just yet because I'm sure it will be good at a few things, but are those few things worth lusting after such an expensive machine? You must remember that my tube is only 20watts and although the glossy hype and demos may tempt to buy a lower power , less eye-wateringly expensive machine, I think there will be little benefit (performance wise) over a glass tube machine. Yes the glass tube machine response time will always be slower when it comes to high speed engraving and as the next video in my series shows , that switching time is vital to fast crisp engraving. but without power ( and that rises exponentially with an RF tube) I cannot at present see anything that makes this technology appealing. I can have 10 Chinese machines, many tube replacements of tubes and significantly more production and flexibility with just TWO cheap machines.. As I will continually demonstrate, linear speed does not get you a faster cycle time on its own. it needs amazing acceleration factors to keep the overrun to almost zero So claims of 2 and 3m/s speed may be possible (they look great on the spec sheet) but what can you do with it if you don't have the power and if it results in slower cycle times. Sadly we never hear the whole story when we watch carefully edited videos. A t present ii have only looked at the fixed amplitude/ varying duty cycle PWM mode of operating. The Ruida controller offers alternatives which I will be investigating in future. I cannot say how other controller work other than to emphasize that there is no magic which amplifies power. If I have a 20 watt tube the ONLY time I am going to get this 20 watts is if I set the machine to 100% duty cycle, so that it effectively emulates a glass tube .....but with lightning fast responses. ANY other mode will reduce that power.. If you can afford a 60 or 80 watt tube then yes, total control of the PWM signal is necessary to control power. I can only demonstrate what the Ruida controller does so do not assume that the expensive machine controllers act exactly the same way. I think this will become clearer when I investigate amplitude control that I think I can access for engraving.
Best wishes
Russ
@@SarbarMultimedia Thanks for the in depth reply, i used to work in a school & used a lotus laser systems 30w Rf machine for the last 5 years, nice bit of kit & we did some fantastic work with it, Last year it started to fall down as it was about 10 years old, then the service provider took the support contract away from the manufacturer & gave it to a bunch of idiots 300 miles away, that was the end of that!
Did you figure out how to make a glass tube faster? Thanks my son and I really appreciate your videos. Your doing amazing work.
Hi
Yes.....and No. Thr reason glass tubes are relativly slow at doing photo engraving is that dithereing an image creates black and white pixels. Black pixels use whatever max power you set and white pixels require zero power. . Zero power means the tube switches off. Every time the tube switches off it takes at least 1ms to switch the power back on. 1ms may sound like a short time but when you are trying to use a 254 ppi image, each pixel is 0.1mm wide. So that is 10pixels per mm. I I chose to run at 200mm/s then I will be trying to reproduce 2000pixels per second The response time of the power supplis 1000pixels per second max so every time I switch off I am going to lose the next pixel (at least). There is no such delay with an RF tube, the switching is instant(ish)and I can run at 1000mm/s without pixel loss. So my thoughts at this time was to see if I could prevent the glass tube switching off during photo engraving so that I could bypass this natural barrier. I had an idea which I test crudely on a glass tube machine with limited success.
To get you right up to date I recently started to investigate this issue again with a more scientific approach to see why my method did not produce the amazing results I had anticipated.
This video explains my method and why it failed. The method was logical but the 40 year old power supply design was just not up to the job. see ua-cam.com/video/_13bnvpdBoA/v-deo.html
Best wishes
Russ
@@SarbarMultimedia thank you very much for your reply. Your video is very educational. Sounds like RF is the way to go if you want to do high speed engraving but is it difficult to get a consistent beam strength across the size of the bed? Thank you
@@icdjpr The fact that 95% the time I use my glass tube machines tells you a lot about what I think of the RF machine. Yes it has some positive points but nothing that makes me fall in love with it. It has been a great piece of comparative experimental technology but......
The problem with a beam that changes diameter the further it gets away from source is a problem that I have not solved satisfactorily. The conventional way is to fit a beam expander. See www.cloudraylaser.com/products/cloudray-znse-co2-beam-expander?_pos=2&_sid=ad11ca2db&_ss=r
I have tried them all and the X2 is the best of a dodgy bunch of kit. These are designed for laser machines because they have special ZnSe lenses. However they are designed with conventional lens theory principles for telescopes invented by Gallileo. Hmmm, I wonder how much he knew about laser beams.?
See www.edmundoptics.eu/knowledge-center/application-notes/lasers/beam-expanders/?gclid=Cj0KCQiAxbefBhDfARIsAL4XLRqOeVlvFBdwjcckHnC_5EMmB6teT-sYWg1gSysmXyEd0mWt65_R2u8aAuQxEALw_wcB
The beam expansion issue becomes an issue if you have a glass tube in a large machine.The 2 to 3mm per meter beam growth has a noticeable effect on cutting performance With an RF beam you are speaking of 7 to 8mm/m beam growth. So, even on my 500x300 machine the cutting performance difference is noticeable without and expander and with the beam expander the difference is less but it degrades cutting performance across the whole bed because the beam has to be expanded to make it parallel (ish). At 30 watts, It will only ever be an engraving machine. Provided you use a compound lens and have the settings right, it is great for photo engraving and with a 2 or 2.5" lens performs well at 3D engraving.
It is possible to overcome both of these issues if you wish to spend mega bucks
www.coherent.com/content/dam/coherent/site/en/resources/datasheet/lasers/COHR_DiamondJ-2_DS_0518_2.pdf
This is 150 watts (cutting no problem) with a 2mm/m beam expansion and thus solves solves the problem....but dont ask the price!!!
You will be able to buy morer that TEN glass 150 watt tubes for the same price and a glass 100 wat tube still beats a 150 watt RF at cutting speeds
You need to think carefully about the choice because the glass tube can do the samer photo engraving job but slower and can then change its character and will cut 20mm acrylic with just 80 watts.
The limitation with the glass tube is the HV power supply as I demontrated in the video link I sent. If this data is true for al lHV power supplies I will,soon find out because I have recently received two different power supplies to evaluate . I suspect they will all be similar .....but I dream they may be more responsive. Thats another future video
Best wishes
Russ
@@SarbarMultimedia my son and I are rebuilding a 120w co2 48"x48" machine right and your videos are priceless and wanted to and wanted to know your thoughts on going to a bigger or smaller tube we are wanting to do engraving and cutting and would love to have a 150w tube and as attractive as that sounds for cutting do you lose the edge on engraving? And we are changing it to close loop steppers 2nm and a 3nm it has 3:1 reduction on both drives and we have seen a few machines with direct drive and was wondering what would be best. Thank you very much for your time
@@icdjpr
Hi Team
48X48 inches is quite a large machine. Cutting performance drops off with distance from the laser source. because of beam expansion at the rate of about 3mm/m Your beam will vary from about 0.3 to 3m so at the extreme corner the beam could be 15mm diameter. because a typical tube of that size will emit a 6 or 7mm diameter beam. The most efficient design for a large bed machine is to remove the "flying" beam from one axis by mounting the tube onto the gantry. In that way you limit the beam to just 1,5m in the X axis only. and beam setting is so much simpler. I50 watts is great for cutting faster and thicker and will be fine for most types of engraving including 3D work Photo engtaving may be off the cards because that normally involves using the preionization operating zone at about 4mA (ish) ALL tubes have this preionization zone but I dont kniw how controllable and powerful it will be for a 150 watt tube.
This size machine is never going to be a greyhound because of head and gantry masses. but it will probaby scan at 500 to 600mm/s (maybe with a loy of overtravel) Direct drive is always a bit of a problem because stepper motors are very "steppy" at slow speeds. To reduce this effect astep down geat is used to drive the axes. ie the stepper motor spins 3 or 4 times fasterthan a dirct drive and thus the rotational inertia of the stepper rotor, tend to smooth out the steps. Th faster the steooer runs the bsmoother it becomes.. However you then have a bit of a balancing act to perform . Stepper motors do not run very fast (600 to 800 rpm) and as they get faster the torque rating drops off quickly.
The down gearing helps to offset this loss of torque. but the inertia of the extra intermadiate pulleys reduces the ability to accelerate rapidly.
It also has an effect on another very overlooked problem ...resonance se this short video ua-cam.com/video/yVbzm41tcy4/v-deo.html
Good luck with your venture . It will be an exciting learing journer both with engineering and ultimately laser technology. If you haven't been there yet you might like to look at this series of videos laseruser.com/the-concise-rdworks-learning-lab-menu/
Best wishes
Russ
The speed of switching is actually a huge problem, at least to me. I could make products twice faster if my tube was able to do that, I am very interested if you came up with that different control solution or not (controlling CO2 tube with PWM)? This would be the best of both worlds if it is possible to make that work. This way I could just install a servo motor on my X axis and engrave with 2000mm/s! :)
Hi Vlad
As I am answering this comment, I am in my workshop investigating the switching speed of a CO2 glass tube laser. I have already done work on this subject in
ua-cam.com/video/_13bnvpdBoA/v-deo.html. I basically discovered that the response time of MY power supply was VERY slow.. Further research indicated that the basic design of the HV power supply is more than 40 years old and was designed for the Chinese by a Bitish professor who ran his own laser company when laser machines werre just beginning to become available outside laboratories and research institutes. As with all things Chinese, they are good at copying but not to good at innovating and updating this product. I currently have two more different style HV power supplies from other manufactureres that I am in the process of testing to see if there is any difference in the response time.. I am just setting up my equipment ,so it is too early to say anything at present. butI will be publishing a video on this subject.
The PWM control of the RF and diode lasers does allow really fast swithcing speed and with my RF 30 watt laser I have achieved 800mm/s with a pictyue resolution od 254ppi. This translates to a dotting speed of 8,000 dots per second. But at this rate you are VERY material dependent and power dependent, so I think 2000mm/s is a bit of a dream for a glass tube.
Best wishes
Russ
27:00 "I've got a much better quality beam from a glass tube by the time I get to my lens than I have here [RF tube]" Russ just fired shots at the RF tube guys!.
I hope you realise that there is very little opinion in this video, just published data laid side by side.........something that you will not have seen done before. That I am disappointed, I suppose, is an opinion, but it is based on the fact that logically I will not be able to magically make all the RF hype come true. I will continue to test the various aspects of the technology but as I mentioned in the video, the capability of the mechanics now far exceeds the capability of the tube I possess I am sure I will be able to create near-invisible "normal" engravings at 1000mm/s on soft card , Why? because there is no magic in 20 watts of RF created laser light. ....even at 100% power it is still only 20 watts.
Best wishes
Russ
Russ, Thank you for this. I have a diy laser lathe setup using a 100w RECI tube. My engraving speed is severely bottlenecked by the switching speed of the tube. I am eagerly looking forward to the installment where you discuss potentially being able to switch a glass tube with similar speed to an RF system that you mention around 44:30. Any direction on how this would be achieved that you could preview for us?
Hi Jonas
Can I ask you to watch this video to start with to see how the OUTPUT DIRECT switch works.
ua-cam.com/video/pwOY-U6BB8o/v-deo.html
There was a lesson in this video that I failed to see and it is relevant to your question.. Whenever the tube switches OFF it takes the response time to switch back ON (maybe 0.5ms). With an RF tube this is microseconds or less. So the problem is how do we stop the glass tube from switching ON and OFF during a scan..... I know that sounds a stupid question because logically it must switch on and off to produce a burn.
OK so if you have watched the video I cite above , you will see how the machine treats grayscale engraving. It varies current flow through the tube, theoretically (because of the physics) at microsend response times. .........unless it sees white 255, whereupon it switches the tube OFF and then requires a millisecond timescale to turn it back ON.
Watch this next video to see how it is possible to make sure the machine never turns off. .
ua-cam.com/video/Iswn-R_mbck/v-deo.html
The example I use is photo engraving because that is most demanding but this technique can be used for any BITMAP image. It will not work with vector images or text. you will have to convert them to a bitmao so that you can further make them into this special grayscale format.
Having put you through that interesting learning exercise , I somehow feel your problem is not going to be solved by this approach........at the moment. Let me explain further.
You mention you have a 100 watt Reci tube (I assume a W2?) That's rather worrying because I and lots of other correspondents from around the world have experienced problems similar to yours with Reci tubes.
I suggest you add your disguised email address to another comment (jonasdot conception======AT ****gmaildotcom) so that we can exchange pictures and more information. I will reply and also delete your comment from public view.
Best wishes
Russ
@@SarbarMultimedia Thanks so much. I do not know if I have a problem with my tube, or if my expectation's are off. The first video you link is very helpful as an example on how to structure my experimentation and measurements. My takeaway from the second video is that by using a gray instead of white the controller pushes a very low power signal that is not enough to mark, but enough to keep the charge in the laser power supply that you would be able to significantly reduce the time it take to ramp up laser power when compared to a fully off position. Anyway I would love to talk shop if your willing. I submitted a previous comment with my disguised email. I'll send another since I did not see it show up.
@@Joncon00
Hi Jonas
Yes it didn't show up
UA-cam is VERY inconsistent. About 5% of all traffic gets sent to a parallel universe. VERY annoying when it's a long complex answer to a comment. Sometimes your comment will make it to the copy they send to my email and yet it still doesn't appear as a comment. Please try again
Best wishes
Russ
@@SarbarMultimedia It seems that my comments with disguised contacts are being removed. Its my full name with no spaces using google's email. maybe that will get through.
Let's call this session a "burning Mr. Cloudray" directly but politely episode shall we :D
Hi
There were no positive nor negative expectations from Mr Cloudray. He gave me this RF tube because he was finding more Chinese companies were beginning to fit these to machines.
He is a wholesale distributor of equipment but he likes to be technically aware of the products he is selling. He does not have facilities nor time to do the deep diving into the technology in the way that I do. He is keen to give his customers good and truthful advice and so far the only "truths" out there are the hyped up benefits being pushed by the "big boys". I have skepticism genetically engineered into my DNA but even I was expecting to find something magical about RF technology. . Hmmmm.... sadly no . It is just an expensive way to create a CO2 laser beam. The PWM means of controlling it seems so simple, but scratch the surface and below you will find a VERY complex relationship between frequency, duty cycle and linear speed. The big companies have written control softwares that hide these complexities away from users. You do not have to understand the technology to use one of the expensive products. No, all you need to do is be able to select predetermined parameters from menus. Thus the technology has been "black boxed" and made user friendly. Selling an RF tube and a Ruida controller is not a good idea and I think just the cost will prevent it ever becoming a serious contender in the small business/hobby market.
In summary I think your reading is incorrect and that my "telling it like it is" will prevent Mr Cloudray from burning his fingers with large stock investment. He will also be cautious with his advice to potential customers.
However, thanks for the comment because others have also commented that this will not go down well with Cloudray. This allows me to explain that there are positives that arise from my negativity and truthful comparisons.
I now have the RF unit and despite my disappointment, I will continue to dig deep to understand the intricate ways that frequency, PWM, and duty cycle interact with different materials. .
Best wishes
Russ
@@SarbarMultimedia ็Hi, thanks for the detailed explanation of the situation. Would you mind giving me a verdict on whether or not I can use my newly ordered 3050 China blue machine with Ruida controller to make proper rubber stamps provided that I am willing to immediately swap out the K H tube and replace it with something more standardise and also willing to run all my jobs at slower speeds (not exceeding 100-140 mm/s) ? I often run into small fonts as miniscule as 4-5 pt on my customer's stamps and if changing out the tube and running the production at slower speed will not help in this scenario, then I can begin to save up as there's a very attractive offer from a "Rayther" brand engraver with size 6040 and 40watts RF tube machine costing $5,500 including shipping (not sure about the quality of their RF tubes) Other more reputable factories such as Aeon or Thunder are giving similar specs offer at double the price. I asked you this again because as I come back to watch your series, it seems that you made a conclusion that RF units are great at engraving detailed drawings at highspeed but I could still not conclude whether running the glass tubes at slower speed would've solve my problem in a "poor man's" way or not :D
Thank you again, Anand
@@avcomth
I have sent samples to you done on a glass tube machine so that you can see what is possible. If you really want to try the RF route then I can see what's possible on my 30 watt RF. The problem is power rather than speed. To cut depth (about 1mm) in one pass requires a certain power exposure time for the material to erode/vapourise Lets say that you can only achieve the 1mm depth if you run at 30 watts and 100mm/s.. If you had 60 watts than you could do the same erosion at 200mm/s. The switching is so instant that linear speed is not the limiting factor. It will always be power. With an RF system the power costs about $800 per 10 watts
Best wishes
Russ
@@SarbarMultimedia OK, thanks again for your kind advice.
I am at a point when I have to decide myself and in research between the two, RF and Glass. the quotes I had for RF were eye watering. Way outside my reach unless reconditioning used unit, and even that is a difficult spend.
So far my findings are quite the opposite, with regards to beam quality and energy efficiency. disregarding the price of course.
I wonder why you have not mentioned power density and spot size when talking about divergence? and Where will a 6mm beam be after a 1m in both cases? at 3mRAD for glass, and I would like to see something other than ebay spec sheet on divergence.... even RECI don't show it in their datasheets. same with m^2 being 1.1
Why not mention power stability when talking about control signals?
Where did you get 9kV figure at 14mA from? is it not closer to 15-18kV at 24mA ? and where did the 3mRAD come from?
Machine I am working with is 2.55mx1.4m cutting area.
I think It would be also fair to include the power used by industrial chiller used to cool the glass tube Vs 12v or 24v fan on the RF tube.
Hi Dave
Thanks for your very interesting questions and comments. I have been using glass tube laser of many types for the past 6 years and have two of my own. I do not run any sort of business with them, they are purely tools for me to decode the laser technology and keep my two remaining grey cells exercised during retirement. I have always lusted after an RF machine because I have seen them at exhibitions and watched quite a few videos. There was some sort of magic in the RF technology that made these machines so desirable . The hype , the claims, the disdain for the rubbish Chinese glass tube technology continually kept nagging at me.
I eventually had the opportunity to find out for myself about this miraculous technology when Cloudray offered me a free 30 watt RF tube to evaluate. I bought a basic machine and converted it to the Tangerine Tiger. I then set about understanding how the tube and the PWM control technology worked. and how it's performance compared with the rubbish glass tube technology that I had invested so much time in learning.
After 21 exploratory/learning session with the machine, I failed to find the magic I was anticipating . I found nothing but smoke and mirrors and the machine has remained switched off for the last 9 months.
To your specific points.
Convergence and spot size are characteristics of a lens and have nothing to do with the source of manufacturer's
Low power glass tubes are short and therefore the voltage required to ionize the very short column of nitrogen gets less. Once triggered, the voltage to sustain the ionized beam drops of to a significantly lower value. Even with my longer 70 watt tube, when I turn the power down to 20 watts it only pulls 12 mA Your voltages and current flows exceed those for my 70 watt tube ( see the SPT C70 specification.) You can see typical low power specs if you look at the C25 tube.
Wow, that is a big machine . That a beam length variation of 4m. A glass tube of any sort is going to struggle over that area because of beam divergence . That will be a huge loss of cutting power from back to diagonal front corner. I have seen this problem on smaller machines than yours and there is a good example of this that I show at 27:10 in
ua-cam.com/video/z8sNPtIIXZ4/v-deo.html
To achieve a uniform size beam you will have to consider a beam expander and I must be honest and say I have never seen a beam expander used with a glass tube .....I think because people don't realize there is a problem. The massive beam expansion with an RF tube makes it a mandatory fitment and there are lots of choices.
I can ask my local machine builder if there is a solution he can recommend
Best wishes
Russ
@@SarbarMultimedia Thank you for a quick reply :) Well caught on the size of table and this is precisely why I have started looking at RF, beam expander and possibly a phase retarder. (So far I think I cannot use the latter with glass, due to random polarisation but I am still researching that) The objective is to have a full 8x4 sheet on the table. I agree, convergence and spot size are characteristics of the lens, I should have explained myself better, I was talking about beam diameter as it exits the tube which is safe to say is 2.5-3 times larger in Glass tubes. That plus beam divergence (my desk based research suggests better in RF) and we start to go beyond standard small mirrors. As for energy efficiency, many of them come with just a fan for a 100W RF tube, whereas a 100W glass tube will need a chiller. It's very interesting to see that you have found beam quality better in glass tubes, this is a pause for me to research a bit more. The gantry is not complete yet and I am only just about to buy the tube.. This is my first machine and I hope I will not get defeated to half the bed size :D Your videos are helpful and thank you for making them!
@@davedavidson4215
Hi Dave
I know the machine builders I have close contact with have made large format machines, but I seem to recall that they mount the tube on the gantry and set the gantry across the 4 ft span That way the beam length change is only 4 ft and glass tube beam divergence is tolerable without any correction. Just a thought if your design/build will allow for such a configuration.
Best wishes
Russ
@@SarbarMultimedia Thank you, all and any input will be very helpful. My build will allow for that and I have a separate rail to make it happen but a thought of high voltage even at those currents and water lines on a moving gantry made me a bit uncomfortable and I will keep it as a last line of defence. If I go glass then it will be most likely a 130W tube, so the change there will be 8ft as I have to place it on the long X gantry in my case.. exciting times!
And Its the same for both of us, purely a hobby, sparked by lockdown in my case :D
I've started seen 100W-150W RF laser tubes go for 7000 to 8000 USD on Alibaba, the commercial brother of aliexpress including RECI branded. I wonder if the investment is worth it. I was really hoping you could take the RUIDA controller to its limits as that's where I believe the limitations will be in the long run. I've been able to photoengrave at 500 mm/s on wood with my glass tube with lets say 90% the fidelity I achieve at 200 mm/s, but past this the results are not reliable, I get all sorts of artifacts and erratic behaviour (memory related) unless I use something like 100 DPI, so even going with a 100W RF tube would still have its limits, I know you are going to be able to figure out how to solve those issues. Best regards.
Isn't this milli Hertz (mHz)?
Nice vid though, thanks.
You are correct . it should be capital M for Mega rather than lower case m for milli. Thanks for spotting the detail....so, I didn't send you to sleep!!
Best wishes
Russ
Real advantages of RF system around 35:00. In the end, doesn't seem way better for the price paid..
I have a 100W RF CO2 laser on an old machine (2009) I bought recently in an industrial auction. It was working great at first for few times. However, now it doesn't work anymore (stays always ON or OFF while moving in the program), I tried to troubleshoot with Laser manufacturer (ROFIN) but they told me I have to change a module costing about 7.5K$USD... Furthermore, they can't guaranteed it will work and the warranty will be only on the module itself and nothing else. I called few people to come see what's the problem but we never really figure it out. I am now starting to retrofit the whole machine (changing motion controller and switching to much cheaper tube). Hopefully the retrofit will be a success. I am waiting for the controller right now.
Hi
You will not be the first. There is a guy in the UK that is regularly "upgrading" expensive RF machines to glass tubes. The one great thing about those machines is the mechanicals. Nice bearings and proper DC servos (usually with rotary encoders.) Team those amazing benefits with glass tube technology and you will have a REAL dream machine. Because of the significan beam divergence of RF "tubes" they MUST be fitted with a beam expander to almost correct this. However a beam expander is great for engraving but it limits the peak intensity of the beam (makes it blunt) and thus hobbles it for cutting. With just an 80 watt glass tube (make sure it is A grade because there is a LOT of junk out there for the unwary to buy) you will already be way ahead for cutting ability. All best wishes for the success of your new project. Please report back when you are up and running ..
Russ
@@russsadler3471 hi Russ, thanks for that. You said I will need to change my mirror and nozzle lens system as well ? How to choose the good lens ? I am thinking about the "best" laser tube company said on the web: RECI, is it right ? I already bought few stuff from lightobject (california) instead of cloudlaser (china)
The old RF I had is a ROFIN OEM10 iX. I was thinking about trying to make the laser works with the new motion controller... maybe theres still life left inside.
You are right about the mechanics, I paid a bit too high in auction but the mechanical aspect is no way close to Chinese machine, it was made in Canada (alphalaser-flx). Mine is not servos nor with encoders but stepper motor (drivers and motors are Parker so they must be pretty decent) but HIWIN bearing rails, special composite type anti-backlash spring leadscrew and adjustable Z axis. Wish to add rotary axis later on too.
When I bought it, I thought myself is even if the laser is bs, I will convert or use the mechanical on something else
@@russsadler3471 i made a post on CNC zone few months ago (same username as here) but it seems YT is blocking me to post the URL... i don't understand why
@@QuebecoisSti
Hi
I am not a Reci lover. I have helped install/ replace 6 different Reci tubes for friends and local businesses.. There was nothing remarkable about the tubes except A) set up to Reci specs they all ran at least 10% lower power output than specified and B) they were all at least twice the price of an equivalent tube from EFR or SPT . Yes, they are nicely engineered but I would never personally buy one.
The other disturbing thing about Reci is that they are moving their final test failures into the open market for sellers to honestly sell as "genuine" Reci tubes but failing to tell you that these are B grade and do not carry a Reci warranty. Reci are not alone in this sharp practice but most others are retested and relabelled with the sellers label
see.
ua-cam.com/video/z8sNPtIIXZ4/v-deo.html
I and others have had less than satisfactory experiences with Lightobject so you will have to make your own mind up on that issue.
I am very sure that the DC servo drives you have will accept positional signals from a Ruida controller so you will not have to make major changes to the control system. Go tothe Cloudray website and all the Ruida controller manuals are there for download. I would recommend the RDC6445. There is the free RDWorks software dedicated to Ruida controllers or a rapidly upcoming piece of software that you should look at called Lightburn.
I can recommend lenses but you may wish o fit a different head to your machine for a much cheaper and more flxible set of lens and nozzle options
Add your disguised email to another comment (johndot smith=====at geeeemail=====dot com) and I will reply so that you can send a few pictures. I will delete your comment
Best wishes
Russ
@@SarbarMultimedia i am getting hard time being able to comment here. Something is triggered and deleting it...
I was trying to find an alternative store of cloudlaser and thats why i choosed lightobject. Hopefully it will be ok... i was supposed to get my stuff last friday but it seems USPS is chaotic before christmas time... i have tracking infos but they arent updated so often.
I already ordered a Trocen AWC 7824 mostly because it support dual motor drive on Y-Axis (which is how my machine is built). I tried to find infos on dual motor drive on Ruida controllers which seems to be the loved and standard one around on the web but it seems it wasn't working. The 7824 is LightBurn compatible according to what they said.
333mmmA1llll below
Clever and interesting and very informative to anyone with the ability to retain all the information russ has given (but) unfortunately for me even though I love his videos (I can’t retain) information like the majority of his viewers due to my epilepsy but tough there is people who have worse disabilities than me : resulting in the fact I’ve still got a brand new K40 I’ve modified now safe to be used and a eleksmaker desktop I haven’t even used either because I cannot memorize every move needed on the computer screen - so my alternative is to get the wife away from custom personalised slate door signs ( hence why I wanted a k40 to laser engrave them along with her way) and her personalised Pajamas she makes although my chances are low at the moment as the amount of orders she’s got ( if anyone is interested in her items) you’ll see the on Facebook under the name ( the little company). Anyway that’s my COVID lockdown rant done and I can’t wait for our next session of these fascinating videos ( without my little rant. Stay safe everyone and goodbye 👋
sounds like with the RF you can use it to light a cigarette and use the wasted energy to make some tea