Review of Opt Lasers PLH3D-XT-50 high resolution blue diode laser head for CNC machines
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- Опубліковано 3 тра 2022
- In this video I review the the PLH3D-XT-50 laser head from Opt Lasers. I mounted it on my AVID CNC and review some of the issues (such as CNC vibrations) with trying to use such a fine beam laser, and go through the different uses and capabilities of the laser. This laser is really ideal for high resolution rastering and etching, but its cutting ability surprised me as well.
Link to the Opt Lasers XT-50 Page:
optlasersgrav.com/PLH3D-XT-Se...
Link to AVID CNC Page:
www.avidcnc.com/
Jim, thanks for this review. I just received my AVID CNC. The laser will be a future purchase so your excellent videos are a great guide in making correct decisions.
Always learn new laser techniques and methods by watching your very informative videos Jim. Thanks for shading your vast laser and cnc knowledge.
Congratulations on hitting 1k subscribers
Thank you. It took quite a while, my content is a little niche :-)
Another great informative review. I though for one horrible minute, you were going to say I should have bought this one instead of the 15W. As I have just spent a whole lot of money on the 15. I have spent the past two days manufacturing a magnetic connector like yours and it works great. Or so my multimeter tells me. I haven’t managed to switch it on yet. Having trouble understanding the poor instructions from Opt. They expect you to have very good knowledge and to be able to work quite complex stuff out for yourself. So much more difficult than my Chinese 10w. I had that running in minutes.
I really appreciate your videos. Just wish I had your knowledge 😄🇬🇧
Cheers Jim
Hi Merv,
Thanks, glad you liked it. You probably bought the right laser, I will still use my 15W one much more than this new one as well. On the info for the laser connector, Opt does have the connector pinouts on their web page for both the control box and the lasers (which are all the same). Let me know if you need help finding the info or interpreting it.
@@JNWoodworks Jim. Many thanks. After I messaged you, I spent a few hours getting my head around it and incredibly it works. Even the magnetic mount I made works. I really don’t know what I would do without UA-cam 😄. Please keep doing the videos.
@@mervhoward5821 Cool!
Hey Jim. Love your videos! Thanks for posting these. A lot to learn for sure.
A question on your laser focal length optimization...
I bought some of those aluminum business cards. Can you post the images you used for the The X Travel vs Z distance and Y travel vs Z distance. Maybe on your google drive that you poste your Mach 4 screensets? Also I'd be interested in a link to the lighted magnifier you used. Thanks.
Hi, yes, those files are in that Google drive already under the directory called "Laser Focus Test Files". You may have to adjust power and feed rate in the files to suite your conditions.
This is my favorite magnifier: www.amazon.com/gp/product/B08S6V7D1V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Thank you Jim, I learned alot about lasers. I was wondering why OPT lasers are so much more expensive than the slew of Chinese lasers on Aliexpress. It kind of makes sense if I compare it to camera gear, it's mostly about the quality of the lenses.
I missed this when you posted it, sorry. There are prettty big differences in quality in the optics, the electronics, the mechanical chassis. The Opt Lasers body is machined out of solid aluminum blocks, and very nicely finished, whereas the Chinese ones are usually just made out of a peice of extruded aluminum heatsink. The Opt diodes are very high quality, and they avoid overdriving them which gives them orders of magnitude more lifetime. The drivers are very high speed - you can run a pwm frequency of 50000 and they work fine. Lastly, as you mentioned, the optics are much, much better. For exmple, this XT-50 has a very well shaped colimated beam to make is symetrical before it gets to the lens. This is how it can then be focused much tighter.
HI Jim, I just discovered your channel and this video and really enjoyed the content. Although I haven't purchased my Laser yet but I have decided on the Opt Laser more than likely the 6 watt.
I already have a CNC machine and would like to purchase another to dedicate to Laser engraving and light cutting. I've looked at the Acro from OpenBuilds and the other OpenBuilds frames and not sure what to purchase. I want a frame sturdy enough to not have some of the issues you describe in this video...
Any thoughts on this?
Thanks, Peter
Hi Peter, The issue with mine is that it is a huge machine with a long gantry and lots of weight from the spindle. If you build a dedicated laser machine, you can mount the laser directly to the Z stage without the extra brackets I have, and you will have very little weight, so you should not have nearly as much vibration problems as I do. That said, for very fine detail lasering of the best quality, you usually have to tune the machine up a little to make sure all the bearings and belts are tight, and that you aren't running too fast, the table it is sitting on is not shaky, etc. When you are making lines that are 0.002" wide, any little vibration can show. There are several people that have different machines on the Opt Lasers FB page. I would recommend asking there what kind of CNC chassis' people have that are dedicated to lasers and see if they have any vibration problems.
The smaller the X and Y dimentions, the better as well. For example, I'm sure you would have very little problems with a 2x3 AVID benchtop pro, they are very rigid.
I am just starting to add the 15W laser to my Avidcnc machine. 2 things, can you share the diagram for your magnetic mount and the tools setup files for the optlaser for the various materials. Great video BTW. Went for the 15W as I would be doing much more cutting of thicker materials.
Hello Pieter,
Please send me an email at jnwdwks@gmail.com, and I will respond with that info.
Jim, When you are cutting through material, have you tried your Z down as you complete passes? Great video.
Typically I don't. Mostly because Vcarve's laser module doesn't support Z height control in their laser toolpath (this has been a requested feature for a long time, by many people :-( ). If its thicker material, I will usually just set the Z height so the focus is near the middle, maybe slightly higher than the center. I don't think that you would want the Z height to be set lower than center, because then the top would end up with a wider than necessary kerf, but if you are doing a few passes, I think it would be useful to work your way down from the top to the middle. I just don't do that now because its not convenient with the software I use to generate my Gcode.
@@JNWoodworks thanks Jim. That's what I thought. I'm not big fan of Vetric software, but I haven't used it very often. You could always write a post processor in perl
:)😀 yep I'm still stuck in the 80's.
@@markedmiston3022 Its funny, most people like one and not the other. For me, I just can't seem to get the hang of Fusion 360. I've done a couple projects and just find it it super inefficient compared to Vcarve. I really like their software, except the laser module, they didn't put much effort into it, and haven't really done much to improve it since the initial release. I am actually going to write a better post processor for laser that converts from a router or engraver toolpath to laser since those toolpaths actually have the Z control features.
Very interesting. Thank you Jim. So, would you say that to cut in 1/4" BBP, it would be best to run in 2 passes to cut straight through?
Sorry, I'm not familiar with BBP, can you give me more details?
@@JNWoodworks sorry, I meant Baltic Birtch plywood
@@barzalou Ah, I should have picked up on that :-).
The XT-50 is not good for cutting Baltic birch in 1/4 inch. It can cut 1/8" in two passes, but 1/4" is just too thick for any medium density or harder wood. The only wood that it will cut at 0.25" to about 0.4" max is really lightweight woods like pine or basswood, balsa, etc. The reason is that the beam has to get too wide on the top and bottom of the cut, and that reduces the power density significantly. It can cut foam rubber to about 0.75" pretty well too.
Haven't been through the whole video yet (over 1h) but how's the Gcode generation? Do you use Vectrice/Aspire ? How it's done ? Is it compatible with alot of motion controller beside Mach3/4 ? (I am using a Centroid Acorn)
Hi, but "it", I think you mean the laser itself? All blue laser heads that I know of use a PWM signal to control their power. Some also have analog inputs, but PWM is pretty standard. Any controller that supports PWM for lasers will work with this laser. The Ethernet Smooth Stepper board in my AVID machine supports Gcode macros for the laser, as well as native rastering (which is nice for doing pictures). For Gcode generation, I do use Vectric Vcarve. They have a laser module plugin, but you can also just modify a post processor for spindles and make it work too (I am going to do a video on that in the next month or so). I'm not too familiar with the Acorn, but a quick search shows that it has supported lasers for a couple of years now, and has a PWM output for lasers, so it should work fine.
Saw exactly that wiggling problem on my laser too. For me, the “start speed” had the biggest impact. Dunno about your controller but my controller goes from 0mm/sec to 10mm/sec with no smooth acceleration.
On the ESS controller I can control the motor acceleration for every motor. I have found that my rastering motor (X) direction is very smooth, but I keep it set to only 15i/s^2. However, when the Y steps for each new line, that tends to cause the gantry to vibrate for a short amount of time. So I set my Y motors to 5 i/s^2 for rastering. That doesn't really impact the overall execution time because its only moving a few thousandths of an inch, but it sure takes out the vibration.
great video! How to connect this laser with the controller ? I have a Raspberry Pi CNC Controller
I am not an expert on Raspberry Pi Controllers, but you just need to find a PWM output for the controller. That is how the laser is controlled. There should be some youtube instructions for that.
If one downside of the high resolution is slower fills by cross-hatching, how effective would it be to slightly defocus the laser to give wider kerfs? I'm mostly thinking of laser engraving wood. Do you lose so much in the laser power that its slower to etch defocused rather than make more passes with a narrow beam.
It is very effective for the 15W laser because for etching a lot of things I typically run it at
@@JNWoodworks Thanks so much! That's exactly the real world sort of information I'm looking for.
Is it possible to attach both the 15w and 5w and switch between them based on what i want to cut.
Yes, several ways. I have a magnetic quick dock on my Z stage, so I can just pop whichever laser on when I want to use it. If you want to mount multiple lasers at the same time and select which laser, it would be easy to put a selector switch on the CNC to enable which one you wanted to use, and you could even make that automated from gcode if you wanted to.
Where did you get that lit magnifying glass? Is that for linen?
I love that thing, and use it all the time. www.amazon.com/gp/product/B08S6V7D1V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Would this fit straight onto a aufero laser master 2 🤔
I know someone who recently put one on that laser chassis. I don't know how much work he had to do to bolt it on, but I would guess that he had to make an adapter plate of some kind which is usually pretty easy. The wiring was pretty straight forward and he is getting great results.
So for laser you need a lightweight belt driven cnc.
Hi Ziyad, Not necessarily. It is usually an advantage to have the Z stage as light as it can be, but you can compensate the weight with running slower, or making the design more rigid. If I were going to have a laser only setup, I would save about 40lbs by not having the spindle connected, and I would also probably only have a 8" Z stage, and I could use a little more direct method of mounting. This would help significantly with speed and vibration. Keep in mind that many laser operations are limited in speed due to the material or processor you are trying to do. For example, burning the the TiO2 in spray paint to a ceramic tile takes a certain amount of time regardless of power so you have to run much slower to get a good quality image.
The chinese diode lasers are at 20W already. Do you know what is the difference between those chinese and this opt laser.
There are now two true 20W output chinese lasers that I know of. They are 4 diode lasers. From reviews that I have seen, the output beam spot is about 0.006" diameter, whereas this one is around 0.002". That means that even though the power is about 3x higher for those 20W lasers, the power density of the XT-50 is still about 2.7x higher. So this laser can do up to 500dpi resolution rastering, and the chinese ones at best will be 166dpi, and you will be able to engrave more materials at higher speeds with this one due to the higher power density. Of course the other thing is quality. The Opt lasers IMO are a step or two above the next best lasers, and many steps above the chinese ones on quality and robustness. As always, you get what you pay for. This laser is really meant for fine detail engraving on many different materials. The chinese ones are best suited to hobbyists for cutting and lower resolution graphics, but not so much picture rastering.
@@JNWoodworks Hi Jim, Re: your comment that the XT50 laser can do 500 dpi resolution rastering, I believe you stated somewhere that you adjust your raster images to 275 dpi with ImagR software. Do you limit your images to 275 because you get degradation above that due to vibrations in the AVID CNC? Also, just for my better understanding of pixels and dpi's, etc... How did you figure out or what is the math behind the 500 dpi value and how did you figure out that the beam spot value is 002"? Thanks, Bob
@@bobmaze2406 Hi Bob. The .bmp image file is basically an X by Y array of pixel data. Each pixel's data consists of 24 bits of color data (8 bits each for Red, Green, Blue). For lasering, only the greyscale values are used (i.e. 0,0,0, 1,1,1, 2,2,2, ...255,255,255). The header inside the file has one other critical piece of info, which is the DPI. That is the dot per inch value, which is how many pixels fit in an inch. From that you can figure out how big each pixel is (1/dpi), and how big the picture will be as well (X pixels wide x DPI = width in inches of the picture). When you load the image into laser software, the software will read the header and figure out how to space the pixels when burning. The pixel array of data is then used to make the picture itself. So to resize, or adjust the pixel size, you have to edit the image itself. That is where ImagR (or gimp, or lightburn, or Adobe Illustrator, etc.) comes in. I use ImageR because it is specifically for laser work and it is easy to use and priced pretty nice. You load the image, and you can tell it to change the dpi resolution, or to resize it. Note that you can simply change the resolution to change the theoretical size of the image. However, real printers/lasers/plotters, etc. all have a basic hardware resolution based on their design, so you are typcially going to find out what that resolution is (you can measure the line width of your laser for example), and adjust the image to that. A laser that has a 0.002" line width is theorectically 500dpi. However, there are merits to oversccaning in some cases where you pretend that it is higher (up to about 2-3x max) to get a more uniform burn (i.e. the pixels are blended together some so there are no noticible transistions between pixels). This is probably most usefull when burning greyscale instead of dithered images.
I should also point out that the pixel size on the same laser will vary due to power setting and material type. The beam's power density is much higher towards the center, so on harder to mark materials (or lower power, or higher speed), the spot size will be smaller because only the highest power part of the beam will mark.
If you look at Nicky Norton's work on Opt Lasers FB group, he is running everything from 400dpi to around 2k dpi depending on the image and material.
I can get the vibration under control just by keeping the speed and/or acceleration low enough as needed.
To get the basic dpi, you can just measure the beam width under magnification by printing lines at known intervals. For example, if yo print lines at 0.002" spacing, then a 0.002" wide set of lines should be just touching.
The other way to do it is to create a small image of a black square, and then make several versions of it at different resolutions and then burn them and see which ones have the pixels that are just touching each other. If there are gaps between them, that means that the dpi value is still too small (i.e. grosser resolution) than your laser spot.
The final thing to say is that for really high quality images, you actually need to burn the image at a few different resolutions a little above where you think it would be from the above measurements. Most people doing the really good work that I've seen (not my own) will try out different values to see what gives them the best image.
Here is the ImagR tutorial page. It has some good processing tips for optimizing the image settings and resolution. www.youtube.com/@ImagR-Laser
@@JNWoodworks Most excellent education on this. Thank you for the explanation! My journey down the greyscale brick road begins... Vectors and Rasters and Dithering oh my! I really appreciate your help!
@@bobmaze2406 I have a ton to learn here too. Cutting things with the spindle is very straight forward, but good laser work is not as predictable and requires a lot of trial and error.