RDWorks Learning Lab 17 Final test of laser power loss

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  • Опубліковано 3 гру 2024

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  • @mesaman3000
    @mesaman3000 4 роки тому

    I am researching this same problem with our laser. A different make and possibly wattage, but same problem. What I have discovered in our specific case, our power supply is rated at 100w and our tube is rated for 80w. We did not adjust the final output of the power supply to match the tube. This caused us to over power the tube. A laser tube exponentially kills it self if you over power it. There are gasses and solid powders in laser tubes to help restore the C02 gasses after each burn. Each time you use a laser, you contaminate the gasses and solids a little bit more. And when you over power it, this happens much much faster. We probably got a couple hundred hours out of a 10,000 hour tube. Most power supplys come in 50 watt increments, where tubes come in all different sizes. IF you have a 60 watt tube, you probably have a 100 watt supply. Operating this at 100% will yield a bad tube in a matter of days...
    There is also a theory that the gasses inside a tube will normally break down over time. This means that if you don't use your laser, it still can loose power, although it happens much slower.

    • @SarbarMultimedia
      @SarbarMultimedia  4 роки тому

      Hi
      This is an old video from the start of my learning journey with Chinese lasers. I now know a huge amount more about the technology and the way in which the Chinese laser industry works.. In general you are right about overdriving tubes with too much current so always fit an ammeter to your machine and never drive your 80 watt tube (if it is really an 80 watt tube) with more than 24mA. The essence of your understanding of tubes is basically correct but there are a few myths and misunderstandings in there as well but they are not important.
      The basic question is where did your tube come from? Was it the original fitted to your machine and did you buy it from Ebay or Amazon Market place or was this a direct import from China. EVERY machine from the first two sources will be fitted with a B grade tube. That means that the tube has failed final tst at one of the main tube makers and has been sold for peanuts to a machine builder for "repurposing".. It will have been tested again to make sure it works "in some way" (enough to fool the average technically naive Ebay buyer) and fitted to a machine. Is your tube labelled K H Laser? If so disbelieve what is says on the label.
      The machines are then shipped in bulk to warehouses around the world from where they are sold by by private E bay sellers in China for commission.
      The tube in this video was serious junk. You will see me replace it with another tube I naively bought from Ebay and that was a slightly better quality piece of junk. It eventually hurt financially when I researched and finally bought an A grade power supply and tube directly from a source in China. The marketplace is saturated with B grade tubes so be VERY careful what you buy. There are very few trusted sources.
      Best wishes
      Russ

  • @k1jo939
    @k1jo939 2 роки тому

    Thanks for the detailed videos. Just wondering if you have (now that the warranty is over) tried adding a milliamp meter in line with the powersupply and tube to see if the current is dropping off. I would suspect the electronics as the probable cause.

    • @SarbarMultimedia
      @SarbarMultimedia  2 роки тому +1

      Hi Thanks for your thoughts. I did eventually discover that my tube was junk. In the last 7 years I have discovered a huge amount about the laser technology andf the way the Chinese laser industry works. Tube manufacture is a very difficult process but there is one key operation during manufacture that must be perferct and that is the two internal reflecting mirrors .
      These mirrors MUST be mounted perctly parallel so that they reflect photons back and foth along the tube axis. . If the reflections drift off then you have a B grade tube that is low on power and having a poor quality intensity profile.. The market is flooded with these B grades that work "in some way"....but not to spec.
      At session 17 I was just starting my learning journey and was naive about lasert technology. I have spent 7 years learning and decoding all aspects of this weird Chinese laser process and I have created a series of easy to understand vidies on specific laser topics, organised in a logical manner to teach newbies all about the technology. This A to Z of lasers can be seen here laseruser.com/the-concise-rdworks-learning-lab-menu/
      Best wishes
      Russ

    • @k1jo939
      @k1jo939 2 роки тому

      @@SarbarMultimedia Thanks Russ. Any advice on Cloudray tubes?

    • @SarbarMultimedia
      @SarbarMultimedia  2 роки тому

      @@k1jo939
      I have no business connections with Cloudray but have a friendly relationship with the company owner. When he began the company aboutb 5 years ago he sought to market some of my designs for a profit share. I declined because I have a nice stable retirement package running that does not interest the tax man . Money appearing from China may rock that boat. I did some more research about Cloudray and found it was operating on a more western business ethic of high quality (but still Chinese products) and great customer service. I contacted the guy again and offerd my designs for free because I do not want the millstone of manufacturing products at my age when a company such as his could service the hobby market at keen Chinese prices. In return he offered to support any reserch I wished to pursue. His help with building a very comprehensive lens collection has ben invaluable because his optical industry contact have supplied many commercially unavailable lenses. With my thousands of world wide contacts I soon get to hear of problems. The B grade tube scam is something I have known about for some time. With Cloudray's aim to supply top quality products, I know the lenghts they have gone to ensure thay are a trusted source for A grade tubes. I regularaly recommend people such as yourself to think twice when you see great Ebay or Amazon tubes at bargain prices.. You are making a 7 or 8 year investment in top power and reliable performance, . if you buy a bargain B grade tube all bets are off. About 4 years ago I discovered a correspondent, who I had steered towards Cloudray , was having some power issues with his new tube.. Upon investigation I discovered he had received a B grade Reci tube from Cloudray. Mortified that my trust in Cloudrat was at risk, I immediately contacted Cloudray to advise that one of the premier tube manufactureres was selling them B grade tubes. It turns out that Cloudray were unaware of the B grade tube "grey market" and were innocently selling what they thought was a trusted A grade product from a top manufacturer. They immediately checked their stock and rejected many tubes. They sent A grade replacements to the few customers that had purchased non conforming tubes,. They then implemented a rigorous tube test procedure before any tube is shipped.. Hence I know for certain that Cloudray are a trusted source for A grade tubes.
      Many believe tha Reci are the best.... not me. I have always trusted the performance and truthful specification fof SPT tubes. Upon my recommendation several years ago Cloudray deided to become sellers of SPT tubes. I always mistrust tubes that have been rebranded because its a pretty sure sign of B grade. However, Cloudray have set up their own rebranding arrangenent with SPT so when you buy Cloudray CR70 tube you are really buying an A grade SPT tube C70 see www.sptlaser.net/co2-laser-tube/c-series
      I have 2 CR70 tubes and they are fabulous performers and 1/3 the price of an equivalent Reci tube A CR70 will deliver 80 watts and despite the specification, the Reci W4 tube is really an 80 to 85 watt tube.
      Take a look at www.cloudraylaser.com/collections/co2-laser-tube/products/cloudray-35-80w-cr-series-upgraded-metal-head-co2-laser-tube?variant=33568306725004
      scroll down to see all the tube tests they perform. I think the mosy important check is the acrylic mode burn tesst that I recommended they implenet. In just a few seconds you chacharacterise a tube. see ua-cam.com/video/R6Wqn5-HMzM/v-deo.html
      Best wishes
      Russ

  • @NFOsec
    @NFOsec 9 років тому +1

    I decided to do the test noted in Lab 16-17 and was rather surprised with the results but probably equally confused. 10% thru 50% pretty much didn't have any major impact, 60% went through is what appeared to be a clear cone with a small focused tip, 70% appeared to be a clear cone with a slightly larger tip, 80% also appeared the same. This lead me to believe that I may at a higher power percentage than what you had -- but it doesn't make much sense unless your new tube changed all that (I'm still on my original 50w laser tube). I suspect I might need to do a test with 80, 85, 90 and maybe 95% power, but one would wonder why I would need that much more compared to another individual with the same machine? Do you know the variables that would reflect this difference? Similarly, I'd be very curious to know what the manufacturer responds to you with.

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому

      +NFO Sec
      First, as expected , manufacturers response was nothing, I bought through a Chinese middleman who knew that he was half a world away and I would not turn up on his doorstep. I went into this purchase anticipating that there would be no lifeboat if things went wrong. However, I did have a lot of completely different experience with industrial lasers which is why I rely on acrylic as a test medium and use the mode burn technique to tell-tale the characteristic of the laser beam. These sealed laser tubes are what they are and you have no means of "tuning" them. Session 27 shows a simplified way for you to quickly run a mode burn sequence automatically. The best and safest way to manage your tube is to add an ammeter to your system (as in session 24). Your 50 watt tube will be little different to others and will have a manufacturer's current limit of 20mA. I am currently awaiting delivery of a calibrated power meter that will allow me to find out exactly what wattage I'm getting for my 65%. You can see the ideal characteristic of a mode burn in session 27, they are all nice cones, just varying depths according to power. The acrylic evaporates directly proportional to the power. So you can see at all stages of power output, the centre of the beam has the highest power density ie it produced the deepest tip of the cone. By the way, a fellow laser machine owner in the States has already tested his machine with my power meter and reports exactly the same power characteristic as that displayed on my machine. He finished up getting just about 50 watts from his 60watt tube at 65% (21mA) also, only an odd couple of watts extra if he over-drove his tube to 90%. Other contributors with much more technical knowledge about these sealed laser tubes report that over-driving them causes the gas mixture to break down and "not lase". Rest it for a few minutes and the gas recovers it's lasing properties but at a slightly lower efficienency. This can be the beginning of the end for your tube, Just before I swapped my tube out it was happily working all day at 15 and 20% power.

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому

      +NFO Sec
      For my tests I was set to 85% but it's now set at 70% which incidentally is the power output when you press the PULSE button.

  • @1010tesla
    @1010tesla 9 років тому +1

    this is interesting. I hope you continue to make videos until this is resolved. Have you considered the High voltage power supply as another possible explanation for the power loss? Its more difficult to measure but I think it could just as likely be a reason for the drop in power.

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому

      +2020tesla
      I will definitely keep the trusty few up to date with my progress on this matter. I have just answered to Phillip Barnes on the same subject so you might like to check out my answer below. I'm sufficiently confident that it's not my use of the machine but a technical issue within the machine that makes it virtually unusable. I plan to pursue the warranty route as my first strategy, but China has gone remarkably quiet. Thanks for your interest.

  • @phillbarnes
    @phillbarnes 9 років тому

    Hi Might be a silly question but have you tried increasing the flow of the water pump and decreasing the water temp. Seams to me that 1 or 2 degrees must make a large impact on tube performance.RegardsPhill

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому +1

      +Phillip Barnes
      Hi Phil
      No suggestion is silly when you reach the point I'm at, so thanks for your input. I'm using the pump that was supplied with the machine which is rated at 500 litres/hour against a 2.5m head, In reality the restrictions through the glass laser tube limit this to about 120 litres/hour. I have tried running the machine with a tank (about 8 litres) of pre chilled water at 12C The water temp went up by about 2 deg over the duration of my 10 minute test but the mode burns were still exhibiting huge power drop-off. I have also tried a coil of copper tube in my tank with cold tap water flowing through. It stabilises the temperature to about 18C but still to no beneficial effect. However, I have not tried increasing the water flow. Something is heating up very quickly (I thought it might be the fully reflecting mirror distorting out of alignment as it got hot.....but why would it get hot?) and then cooling down equally quickly when the power is switched off. Just maybe, an increased flow rate would have a greater effect than pre-cooling the water BUT the point is that the equipment I bought should be tried and tested to perform as a 50 watt laser SYSTEM .....and it doesn't so I'm suspecting a faulty laser tube. Many thanks. Russ
      p.s. By the way, there is no recommendation for the cooling water temperature in the manual.

  • @chrisnoble9592
    @chrisnoble9592 4 роки тому

    Hi
    Did you manage to get to the bottom of the power loss issue? My 100W laser is exhibiting the same problem, any guidance would be appreciated.

    • @SarbarMultimedia
      @SarbarMultimedia  4 роки тому

      Hi Chris
      Yes eventually. But before then I gave up with this first tube and in my naivety turned to Ebay to buy a replacement. BIG MISTAKE. As you move along my learning journey you will see that it was really just better quality junk. As I gained more knowledge and had more correspondence from all over the world, a very clear picture began to emerge of how many Chinese machine builders are preying on technically naive E bay buyers.
      A) They advertise 40 watt machines as 50 watts ,50watt machines as 60 watts and 60 watt machines as 80 watts( you get the idea)
      B) For almost free, they they acquire reject tubes from main tube manufacturers. They retest them to make sure they work "in some way" (because with a proper power meter and an ammeter how would anyone know?) A major culprit tube will be labeled K H Laser (is yours?)
      C) They usually fit B grade HV power supplies that will work quite well but have failed the response time specification and may not engrave all that well at high speed.
      D) I have even seen another expensive component, the Ruida controller without bar codes are model label. Again B grade.
      E) Generally mechanically OK these machines then get shipped to warehouses around the world where they sit for months while a team of PRIVATE Chinese ebay sellers try to sell them for commission. The promised support and warranty is worthless because the seller has no tech knowledge of the machine and will close the ebay account at the first hint of him losing his commission. You will note how the factory is purposly ducking any resposibility by hiding behind a third party (perhaps better described as a puff of smoke)
      Determined to not get screwed again, I researched well before I bought tube number three and a new power supply. It was an expensive lesson but more than 4 years on it is still performing like new. In the meantime I have found a company in China that I can 100% trust.
      Attach your disguised email address (chrisdotnobleatyahoodotcom) and I will send you some guidance. It's a laser jungle out there for the unwary.
      Best wishes
      Russ

  • @mno4282
    @mno4282 8 років тому

    ok i think again that is specific of co2 laser and degradation of gas inside tube. After some time gas regenerates to it previous state

  • @Michael-lo3ht
    @Michael-lo3ht 5 років тому

    I can't find which video you compared using different air pressure on air assist?

    • @SarbarMultimedia
      @SarbarMultimedia  5 років тому +1

      Hi Michael
      You must always remember that this is a record of my zig zag learning journey and not a set of tutorials. I come from a background where I had lots of experience with metal cutting. To achieve good efficient cutting I was using high pressure air at 8 to 10 bar, or pure oxygen at 2 to 3 bar or medical grade nitrogen at 15 to 20 bar depending on the metal being cut. I tried using my shop compressor when I first powered up my China blue machine, because I rolled around with laughter at the stupid little pulsing air compressor supplied . 4psi??? (0.3bar) Joke. I wont go into the whole story but after 2 weeks and 2 damaged lenses I reverted back to that pump I had laughed at. It has been serving me well for 4 years and I haver the same compressor o the Lightblade machine. For cutting you do not need high pressure , you need efficient flow through your kerf and 0.3bar is perfectly adequate to blow all your fumes out of the bottom of your work . So for clean efficient cutting you need a small orifice nozzle (2mm to 2.5mm diameter and that nozzle must be set close to the work (3 to 5mm). With engraving there is no bottom exit for your fumes, they have to come upwards and there by is a problem that most do not understand . If your fumes explode upwards then the last thing you want to do is blow them back down onto your work with air assist. For engraving you need a big gap between nozzle and work (at least 12mm) . a big orifice in your nozzle to letb the beam through and just a whisper of air assist to protect the lens. The important thing which most folks fail on is air management. You must make sure that your engraving fumes, once airborne, remain so by being quickly carried away by a CROSSFLOW of air.
      This is a summary of many videos and experiments with lenses, air assist flows and pressures. and cutting/ engraving efficiencies. and may save you many hours of "looking over my shoulder"
      Berst wishes
      Russ

    • @Michael-lo3ht
      @Michael-lo3ht 5 років тому

      @@SarbarMultimedia Russ. Thanks for the reply. I thought maybe you remembered which it was in. I was going to point someone to it. That's quite alright. I'm hooked on watching your videos. I think mainly you bring it down to earth and it's your journey as well. Also you explain why you're doing stuff. Thanks again. I refer people to your videos a lot.

  • @RazvanXob1
    @RazvanXob1 9 років тому

    Hello. I bought the same machine 2 weeks ago and i think i have the same problem. Can you please tell me the average power/speed for cutting 3mm mdf? I manage to cut only first half of the project with 7 speed and 80% power.

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому

      +RazvanXob1
      Read the last reply I made to Phillip Barnes below. It is important that you act very quickly because the people in China understand the E Bay and Pay Pal rules better than most of us. Register a dispute/complaint with Ebay immediately. I would advise against "not as described" rather use something like " arrived damaged" They will probably ask if you checked it with the courier on arrival. You will have to answer yes but add "until you plug in a light bulb how do you know it's damaged?" Say that the whole point of the machine is the laser tube and its not working. Don't give any indiication that it may have worked just emphasize that the machine is not ready to use out of the box and it takes time to assemble unpack and power up, whereupon you discovered the non-functioning laser tube.
      In the meantime you need to understand what I did in session 16 and 17 to prove that the power was dropping off almost immediately I turned the laser on. The mode burn straight out of the laser tells you the whole story immediately. You must use acrylic sheet for this test because it evaporates when hit with the laser beam and the amount of evaporation gives you a good way of mapping power loss with time.
      I would expect 50% power at 10 or 12 mm/sec to easily cut through 3mm mdf

  • @phillbarnes
    @phillbarnes 9 років тому

    Can't paste embedded code for some reason or paste a link so type into the youtube search bar, LPFthingsThis guy has the same laser cutter as you in tropical Queensland Australia, it's hot. He may have some ideas for you. Have you had a multimeter connected from the laser power supply to make sure the current isn't dropping off?

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому

      +Phillip Barnes
      Hi Phil
      Thanks for your suggestions. Yes, I visited LPFthings and many other contributors who already owned the larger format laser machine before I even purchased mine. I revisited some and found more in my search for help about using the machine. I'm sure temperature will not be an issue for me as several users are saying that up to 30C is ok and that will be easily achieved with my copper cooling coil. Only when I get a consistent performing machine will I be able to check the temperature at which performance starts to be impaired . I understand your point about checking the power supply drop off BUT there are two issues here. Firstly I know enough about electronics to know that I wouldn't have a clue about how to check the low voltage side of the circuit and secondly, even if I could, I'm not sure I would mess around with a machine that is still under warranty and clearly not fit for purpose. I'll wait a few more days for a response from China before contacting PayPal

  • @anthonydurnin5614
    @anthonydurnin5614 8 років тому

    hi , im in need of some advice, I recently bought this machine to mainly use it to cut out 4mm plywood, but it doesn't seem to cut through it or it might cut through the first shape and continue to lose power. is this a machine problem or a mirror setting problem regarding the power output needed to cut this material.

    • @SarbarMultimedia
      @SarbarMultimedia  8 років тому

      +Anthony Durnin
      Hi Anthony
      My immediate question is to ask what power % are you running at, as what you describe has all the symptoms of over driving the laser tube. I can guess that your machine is not fitted with an ammeter and you have no idea what you should be running your tube at. There's a programmable power range of zero to 100%, why not use it. If it doesn't cut at 50% then let's try 95% WRONG. In my ignorance I did just that and wrecked my first tube.
      Logically, if the machine was cutting initially and then reduced it's power output , it will be nothing to do with the mirrors, they are just innocent bystanders. What power is your machine supposed to be and what's the approx length of your tube?
      You may have been attracted to this video because it's title matched your problem.
      It is just one in a numerical series of videos that I have been making since I first bought my machine. The series documents the learning cycle I've been through, the discoveries and the mistakes I've made. 7 months on, I'm in a happier place and having great fun. I'm also still continuing to learn things about my machine that may benefit others because there is much myth, here-say and conjecture about these machines and little documented fact. So there is a trail of what I've learnt if you wish to follow it.. However, if you wish to message me with your email address (click the Sarbar logo icon, then the ABOUT tab and top right will appear a message button) I will attempt to help you off line.
      Regards
      Russ

    • @anthonydurnin5614
      @anthonydurnin5614 8 років тому

      +SarbarMultimedia hi again rus my email is antodurnin@gmail.com all help is hugely appreciated thanks

  • @MM-oh3zs
    @MM-oh3zs Рік тому

    Water temp at the time??? The is a huge difference between cuts if your water chiller cannot keep up keep the steady temperature (i.e. 17C)

    • @SarbarMultimedia
      @SarbarMultimedia  Рік тому

      Thanks for your comment but note this was 7 years ago as I was just beginning my laser journey. I had no idea about the Chinese tube frauds that took place and this tube was acually junk. I now have sufficient knowledge to say exactly why it was junk, It was internal mirror alignment issues ( not temperature) and this tube failed final test at the factory and was sold for scrap value into a "grey" market. I replaced it with another "suitable replacement" (from EWbay) that was also junk. After some research I bought an A grade tube from Mactron. It was expensive (at the time) but here we are 7 years later and it's still performing like new. I suspect your 17C comes from using a CW5000 or5200? Here are two things for you to think about.
      1) I have carried out exteneded testing (with an A grade tube) between 5C and 45 C and after running several full power hours at 45C I measured a 5% power loss at the higher temperature.
      2) One of the premium tubes you can buy (Reci) recommend a water temperature range between 10 and 50C.....not much difference to my own experience.
      The agressive cooling with the refrigerated "industrial" chillers is the cause of significant power variations that will be seen asl light and dark banding on photo engravings.. That's a whole different story that I have researched

  • @phillbarnes
    @phillbarnes 9 років тому

    How have you gotten on with your machine or the manufacturer?

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому

      Hi Phil
      I sent this You Tube link to China but my viewing statistics tell me zero views on that continent. I suspect this channel is blocked so they cannot view the video. That said, they have received 2 emails in the last 10 days and I have had no reply. Their Ebay advert states two working days for a response. I have just converted the mode burn results to a series of jpgs which I have attached to a new email advising them of 11 Sept as a deadline before I lodge a formal dispute with Pay Pal. Will keep you all informed with a new video. Thanks for your interest
      Russ

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому

      Hi Phil and all New buyers
      If you have recently bought your machine you might like to test the laser on near full power sooner rather than later. I didn't do this until several weeks after I had purchased and now I find it's not working at full power for more than tens of seconds. There is a VERY short period that Ebay cover you for goods that are " not as described" and PayPal class such problems as a warranty issue and advise taking it up with the seller. The seller is in China and couldn't care less about my problem now that they have my money it may take several weeks before I have a result but I'm now working the problem from a different angle.

    • @jo5817
      @jo5817 9 років тому

      +SarbarMultimedia Hi there, I've come across your video's and whilst they are extremely useful, I am concerned that I am going endure hours of pain in getting my machine working, only to find that it won't do what I need it to do. I purchased the machine to cut designs from 3mm acrylic, bamboo and MDF - what are the odds of this working? Thanks in advance.

    • @SarbarMultimedia
      @SarbarMultimedia  9 років тому

      +Joanne Samaradellis
      Hi Joanne
      If you have been watching my videos in sequence then you will observe clearly that I am not an expert but someone just like you trying to learn about this machine with very few instructions. I have made mistakes. The most serious is that I ran the machine for long periods at 95% power to see what it was capable of. When I noticed the power loss it was too late, I had damaged the laser tube by over driving it. Although I can see now that it was my fault, there were no instructions or warnings about this. I replaced the tube, and fitted an ammeter (there are videos about each) to make sure that I stayed within the manufacturer's limit. I find that my limit is now 65% power in the program to get supposed max power from the laser. That max power should be be 50watts but I have yet to prove that. It will be the subject of a future video. To answer your concern, I can now cut 8mm acrylic (very slowly) in one pass and it will eat 3mm acrylic at about 15mm/s.You can see it cutting 4mm plywood in one of the latest engraving videos and I have done 3mm and 5mm MDF and also a small trial cutting 4mm leather.
      On your own it may be painful but the path that I have beaten for you and the mistakes I have made should make learning a pleasant experience. If you get stuck you can always contact me

    • @jo5817
      @jo5817 9 років тому

      +SarbarMultimedia
      Thank you so much for getting back to me.
      I've just attempted my first cut with thanks to your videos, and it started off great but lost power and didn't finish the job. I was cutting a simple image in 3mm bamboo. Powers were min 80%, max 95% at 15mm speed. Thoughts?

  • @roydavies953
    @roydavies953 8 років тому

    The glass tubes dont will not last forever....the more you use it....the quicker it will lose power, also i think you have to replace the mirrors, are you cleaning your mirrors .