Have you ever tried laser etching photos on eggs?
No, I haven’t. I’ve threatened, over the years, to build an Eggbot and a rotary axis but, always resisted… telling that part of me to “go away… I don’t like being bullied.” 
I’m more likely to entertain that now, living in proximity to some of my grandkids. I’ve also confirmed that the white tile etching method also works on plain glass… so am positive you could etch mugs, glasses, etc…
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It works on plain glass as well?? I’m sold! Can we see up against the light?
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I’m curious, when glass (or tile) is lasered, does it affect the surface texture or is the image below the surface?
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It leaves a hard, slightly raised, texture on the glass… where the paint/glass are hit with the laser
This is all done with a simple little 2.5W diode laser. The glass is first coated with a light coat of flat white spray paint, allowed to dry, the image is lasered, and the paint remove with thinner or acetone.
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Probably what piques my interest. I enjoyed seeing what you’ve done on tiles and the addition of glass makes it all the more interesting. I want to gain some proficiency with my MPCNC first but this certainly holds some interest for the future. Thanks!
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In case you are looking for an eggbot design to use V-Slot, Here is one I designed. I put it all together & then got side tracked on my rolling plotter design. Maybe I will get back to it over the winter, but it is essentially done & just have to test it. It uses 2 - 2020x250mm V-Slot. The files are under the files tab of my build log located here:
https://openbuilds.com/builds/v-slot-2020-eggbot.9080/
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I’m continually amazed by the things people create! 
My Ukrainian Grandmothers who did their eggs with melted wax and dyes in an artform known as pysanky would’ve been dangerous had they had one of these machines. 
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@dkj4linux So you seem to be the resident laser master around here. My question is, what do you recommend for a diode laser that will engrave and etch, but also cut through thin wood. Nothing crazy like 1/2" or anything, but like Luan or thinner.
How about something like this for working with mugs?
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IMO it’s really not the diode laser so much as it’s the material being cut. Thin solid wood cuts much easier than plywood of the same thickness, generally. I cut 1.5mm craft sticks (birch, I think) and balsa in one pass with a 2.5W laser. Plywoods, however, have glue between the laminations that make cutting it totally unpredictable… it may, or may not, cut in a reasonable number of passes with a low power laser.
Crucial, however, for cutting is to have absolute best focus possible. For me, it’s usually on the surface of the material being cut and Ryan’s focus script helps immensely to determine that. Some folks suggest moving the focus point to the middle of the material… others to the bottom of the material. Ryan’s script helps there, too… focus to surface and then lower by half or full thickness, depending. Interestingly, it often happens that higher-powered diode lasers don’t significantly improve performance… often their spot size is larger and the actual power per unit area is actually less than with the smaller spot size of the lower powered laser.
Air assist will help also. Something generally stronger than the typical Walmart aquarium pump. I don’t go particularly crazy, however… and use Danowar’s air assist shroud with the Banggood/Eleksmaker 2.5W lasers I’ve used in the past.
OK, thanks for the info! I’ll source one and see how it goes.
Okay… today was laser day.
Remember the “20W” laser I “zapped” with static a while ago? I ordered a new controller off Ebay that looked as though it should work.
I set up the “zapped” laser module for retest… to confirm what I was seeing before setting it aside.
Sure enough it was acting the same way… Grbl gcodes M3S0, M3S10, M3S100, M3S500, M3S1000, M3S0 seems to be working… but the laser output was pitifully weak. So I removed the old laser controller board and installed the new. Fully expecting to see the laser at full power again… I was disappointed the see that the new one acted exactly as the old one did. So, now I know the laser diode itself is what suffered the static damage. Oh, well.
Here are a few photos of the board replacement. The test set up with just the laser power and PWM outputs hooked up (not seen is the Pi 3B+ and CNC.js I’m using to control things)…
The replacement laser controller board in the middle…
Old controller and fan disconnected from board…
The old controller board (bottom) and new (top)…
The new controller board has been installed and powered up…
As noted, the new board acted exactly as the old one… it recognized gcodes, but the output was pitifully weak. So, one mystery “solved” (that is, I know what’s wrong with it)… and on to the next.
I received a second Neje 6W laser module this past week, finally catching up with @geodave… <nah-nah-na-nah-nah!> 
And, though I had ordered and received the 5v to 3.3v level converter boards as well, I still questioned the need for them. So I revisited all the Neje laser module webpages I could find once more, seeing time and again the 3.3v - 12V PWM claim on the modulation input… and since I had a working lashup sitting there on my “bench” I decided the heck with it. So I unpackaged one on the Neje modules and hooked up the power pins to +12V and GND… and the PWM pin to the same +5V PWM I use with all my other lasers. And, voila! A working laser.
Time will tell, of course, but I’m pretty sure the Neje laser modules PWM input is relatively “bulletproof”… in the least, handling +5V PWM okay. This pretty much sets my mind at ease and, providing these work as well as hoped, it’ll be nice to have a line on a relatively inexpensive, and reasonably powerful, diode laser module. Thanks, Mike, for providing the link!
– David
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I just got a 3.5W Neje laser module from Banggood after following this topic for a while. Looks like they are still available, In any case I have been following the PWM voltage issue (planning on using grbl ESP32 at 5V) but can’t recall a discussion on frequency, any suggestions? I think I can set it up between 5-20KHz.
I’ve never concerned myself with the PWM frequency, as both the Marlin and Grbl defaults have always worked fine with my lasers. Currently, I prefer Grbl when setting up a laser… I find its “laser mode” ($32=1) is fantastic with its smooth motion and variable power with feedrate. With regard to PWM frequency, from the Grbl documentation…
“By default, the spindle PWM frequency is 1kHz, which is the recommended PWM frequency for most current Grbl-compatible lasers system. If a different frequency is required, this may be altered by editing the cpu_map.h file.”
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Is something like this cut from 3mm MDF or other similar thickness wood possible with the 6watt diode laser? I am guessing we have 1/8"(3.175mm) wood instead of 3mm in U.S.
Dave,
TBH I’m disappointed in the performance of the Neje 6000 laser module in my initial testing. I had hoped (without really checking beforehand…) that this was a “real” ~6W laser… but alas, it’s not. I pulled the Eleksmaker 2.5W laser off my rolling gantry machine, replaced it with the Neje unit, and then ran a couple of my existing gcode files with hopes of seeing signs of greater power from the Neje module, that would need to be toned down. But no such luck… it barely seemed the “equal” of the Eleksmaker unit. It also seemed not to focus to as small a spot as the 2.5W unit… with resulting “less fine” engraving lines.
YMMV… but this is what I saw. Checking – after the fact – a listing for the Neje 6000 (which is now discontinued), I found what I now suspected… it is, like all those “misrepresented” higher-powered diode lasers, “rated” by its input power; i.e. 12V at ~0.5A, or 6W.
That said, if you need a ~2.5W laser module, this will probably do a passable job… just don’t expect it to do much more than any other ~2.5W laser out there.
– David
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Can you confirm that 100% 3.3V is the same strength as just wiring it to 12V? I assume it would be completely “open” with 3.3V, but maybe it isn’t.
I think this is what you’re asking…
To its credit, the Neje module will not fire with just 12V applied and the PWM input disconnected. It apparently has its input internally pulled-down… and doesn’t fire suddenly with the application of power, as so many other laser modules will do. Just to check, I put the Eleksmaker unit on the worksurface, applied 12V only (modulation input disconnected), and it indeed fires with full-power.
Is that what you were asking to see?