DIY Galvo scanner with PWM controlled diode laser

Hi everyone!
I’m new to this forum and looking for help on selecting the right DSP controller to drive a cheap chinese galvo with XY2-100 interface in combination with a PWM controlled diode laser.
Can anyone suggest a not too expensive controller with XY2-100 interface and TTL PWM output which is compatible with LIGHTBURN? An additional control output for a stepper motor Z-axis driver would also be a nice option.
Best Regards,
Dirk

If you’re trying to build a fiber laser, at this point in time, I don’t know how reasonable that is.

There is no pwm control to a fiber laser and the galvos seem to have a different interface than stepper motors, labled similar, might be power, they don’t need much.

There are limited controllers out there that Lightburn supports as far a using galvo, but some are appearing using grbl gcode, but I’m not familiar with them or how they’re implemented within Lightburn …


I have a BJJCZ USBLMCV4 EZCad2 board in mine. You can check this link for a couple of the new boards that are supported.

EZCad3 and it’s new board isn’t supported yet, which includes a Z axes control. This is the manufacturer of mine.

I don’t think I’ve seen any of these that are supported for <$400, this is just the controller.

What kind of galvo are you attempting? Welding, 2d/3d?

Laser source?

:smile_cat:

Check if the following links helps.
https://wiki.fablab-muenchen.de/display/L4DIY/LASER4DIY

https://wiki.fablab-muenchen.de/display/L4DIY/Laser4DIY+Micro+Chip+Laser

Yikes !

:smile_cat:

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Thanks for your suggestion. I found to the same company doing my own research, but I didn’t find any suitable board that would support my plan out of the box. I ordered a relativeley cheap BJJCZ board which supports fiber lasers.
Tha laser I intend to use is a 405nm diode laser which uses just an PWM input for modulation. I will probably have to match the fiber laser output to a simple PWM output via some adapter hardware and/or software, which converts the digital PWM signals of the BJJCZ board to a simple PWM. The idea is to take the digital TTL PWM output (P0…P7+PLATCH and convert it to a simple TTL PWM suitable for the laser. The setup will be used for 3D SLA printing with the laser facing down on a Z-axis controlled build platform which is submerged in a pool of resin.
The galvo is a cheap HUNST galvo originally designed for 355nm fiber lasers.
For the first attempt speed is not that important, so I assume the 500mW UV laser will be able to cure the resin and be able to follow the power output from the BJJCZ board. The final goal is to do something similar to this: https://youtu.be/39f6e_OuFHU?si=a03KwFgud0RbSV9c
Not for heat shields, but for cusom made catalyser carriers and heat resistant parts for a chemical reactor.

Thanks for your suggestion. I’ll have a closer look later.

It’s not a pwm ttl output, it’s a parallel 8 bit word… As far as I’ve seen there is no pwm output from these boards, but I don’t know them thoroughly.

Did you look for a module that would drive a galvo co2… they normally are driven by a pwm out of the controller… That would eliminate any extra hardware.

How do you think you will control where the laser will set the resin? As soon as it leaves the lens into the resin I’d think it would solidify…


In the video they are laying down a 50 micron thick layer of resin then set the needed area with a laser. Then another 50 micron thick layer and so on.

There was no mention of the power levels they are using… I doubt it’s 0.5W like you are suggesting, but I don’t know.

I know these are usually done with a lcd screen… so it might be plenty… I’d hunt around and see if what you are attempting to do is actually feasible before spending the money and time.

Are you sure of the lasers frequency and that used by the resin? Seems to me they were using a visible laser…

Good luck

:smile_cat:

I know it’s a parallel output. I’ll measure it with a logic analyzer, once I have access to a complete setup. Depending on the speed of the signals I’ll use a Microcontroller or an FPGA to reencode the signal to a PWM signal. My assumption so far is. that the P0…7 signal is used for the pumping diodes lasers and the other signals are used to drive the q-switch of the fiber laser. Maybe converting the signal from the P0…7 to a single pulse with a length defined by P0…7 and triggered by the Q-switch signal will work. For controlling the laser position the galvo will be used. I did some tests with some resin in a petri dish and a 20mW 405nm laser and found that even 20mW is plenty as even the reflections of the laser spot under the petri dish caused some curing. So I guess a moderateley fast moving PWM modulated laser could do the job. The resin is specified for 405nm. A fiber laser with 355nm should work too, but the pulse energy will probably rather evaporate the resin than cure it unless I use a really fast scanner. Maybe this will be the way to go, once the proof of concept phase is finished.
Does anyone have information about the laser feedback signals LASERST0…3?
Those might have to be emulated too, to ensure the controller board doesn’t pause the galvo. It’s really difficult to find iformation covering the protocols online. Any hints?

Different frequencies?

I really don’t know much in the way of details on how these operate.

I’d like to see any photos when you get something together.

Good luck

:smile_cat:

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