Machine to run Blue Diode Laser and CNC

Custom machine to be build from scratch

I just picked up a 3 axis older inspection machine. It was converted to a CNC 15 watt blue diode laser. Since this machine is really stout, what I would like to do it make it into a combo Laser engraver with the blue diode and CNC machine for soft metals and wood. I would love to use the C3D board since I like how it interfaces with lightburn and has proper PWM control at good speeds. I have the following questions.

  1. I assume I can run a PWM output to the Blue Diode Laser to get true grayscale engraving using
    lightburn. Is this a true statement?

  2. I am totally in the dark in terms of what to do for the router control. I am new to this realm. I assume
    that features I need for running router control are as follows:
    a. Can I do bed leveling compensation with the C3D?
    b. Can I have it stop for tool changes?
    c. Can I run a Spindle on/off as well as spindle speed control from the C3D?
    d. Please list any other features I might be looking for?

  3. I am running Fusion 360 for mechanical design. I see there is not a gcode post processor specifically
    for C3D but it seems there is a smoothie post processor. Will this work for the C3D?

  4. If I have an STL file that I want to cut using the C3D, what software would I need to create the
    toolpathing and get true 3D engraving(not 2-1/2d)

Mainly, my concern is running a router and a laser from the C3D board and having success with both. I am looking for the best option in terms of hardware and software to be able to accomplish this.

Thanks in advance for your support


It’s going to be pretty difficult to get this doing double-duty for that application.

  1. Yes, PWM is available for the diode; depending on the configuration/needs of the diode module you can either use the L/GND terminal blocks like you would with a CO2 laser, or the alternate +5V PWM output terminals adjacent to the screw terminals for this purpose.

a. unknown. TBH i’d work on getting the bed as level as possible mechanically rather than relying on software to do this for you. Tool post dial indicator holders and shim stock are inexpensive and can assist with mechanically leveling the bed.

b. Most of the CNC routers I’ve dealt with handle tool changes by sending multiple G-Code programs to the router, ie. when one program finishes it’s done with that particular tool and you change the tool and load the next program to continue. Cumbersome, but that’s how it’s done. It’s probably better this way anyways, 'cause about half the time when tightening the router collet I end up shifting the carriage and need to re-home the machine. Not to mention the fact the Z0 will need to be set at every tool change since the machine has no concept of stored tool lengths and taperless spindles offer very poor RTZ on tool changes.

c. You may be able to remap some of your unused endstop inputs to perform these functions. Note that whatever spindle controller/VFD you get will need to support PWM speed control as the laserboard is unable to provide a 0-10V analog signal natively.

  1. The Smoothie postprocessor I assume would work, however I’ve personally not tested this at all. The controllers I’ve used have mostly been Grbl-based.

  2. Fusion360 can import STL meshmodels and convert them to normal bodies upon which regular toolpathing operations can be performed (YMMV - fusion’s pretty picky about it and seems to hate triangles). From there it’s all dependent on your skill/patience creating toolpaths and the particular tooling you’re using to determine whether or not a machining operation will be possible. Keep in mind with a basic 3-axis machine a lot of your operations are going to be pretty limited in scope.

Here’s an example of someone who’s done it already:

Thanks Loather

Is there any best solution to doing what I am trying to do? Is there a possibility of running multiple controllers? I really want to get going on this project but I do not want to spend dime 1 until I feel I have the best solution. What would you do if faced with the same problem?

Honestly? If I were faced with the same problem I’d plan on building two machines: one for routing with perhaps a more tailor-built controller (not saying Smoothie or the Laserboard can’t or even shouldn’t do it, but it’s definitely geared more towards laser than CNC use) and another (using the Laserboard, of course) for the diode laser.

Running multiple controllers on the same hardware is one of those situations that perhaps can be done, but probably shouldn’t (there’s really no way to not make it ghetto).

If you’re out of space and can’t physically fit two machines or want a challenge project or something, I’d definitely suggest going with one controller over two and possibly finding some creative ways to solve the problem with what you have at hand. Trying to have two controllers talk to the same motion control is asking for trouble.

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