Show me your dual source setups

I’m thinking of adding a diode source to my co2 laser. I have a rdc6445g so I should be able to make that work (and if not I’d put in some hardware switch anyways). I’m more interested in seeing how people have mechanically attached both sources.


A few people have attempted this … The basic Chinese laser is a general description… how it’s actually built is up the manufacturer, meaning there is no real standard on how these are mounted.

I replaced the head and drive on my OMTech China Blue and the laser module on a couple of my CNC3018 types… Both required me to design some type of mount.

A Ruida doesn’t use/generate signals for a dpssl type.

The lps requires a pwm signal to set it’s current, and an L-On (laser enable) to instruct the lps to lase the tube.

On a Ruida the pwm is generated continuously when the machine is running a layer, it does not control when the machine lases only the current setting of the lps.

You’d have to implement some type of logic gate to allow for a proper signal to the pwm input of the dpssl module. Pass the pwm signal only when the L-On line goes low…

Make sense?


1 Like

I had read elsewhere that the ruida can run in the correct mode for the diode, just not both co2 and diode at the same time. I’d have to change profile each time. Workshop real-estate is my real limiter so compromises in building this kind of mash up is worth it for me.

And yes, I’ll absolutely have to make a bracket! Lol

There is no option to drive a regular dpssl from it without some kind of external logic. If you can find the source where they claim this, I’d love to read it.

There is no doubt you can do it, it’s just not a simple option change… PWM is generated throughout layer execution… you can’t change that… so you need external logic to generate the proper signal.

Although the Ruida allows you to invert the L-On (laser on) that’s the scope of what you can change with it’s signals. And that really isn’t of much help in this situation.

Good luck


Wouldn’t the PWM generated by the controller still match the power proportions specified either during a cut, engrave, or traversal?

A diode laser would only need the presence of a non-zero PWM to fire in which case L-On becomes irrelevant.

One note is that the laser type likely needs to be configured as RF for this to work properly. L-On is disabled when configured as RF. I assume no-preignition pulse would be required.

Also, I assume that power is being supplied externally although a 24V laser module would probably be fine being fed by the stepper power supply.

I think we have some miscommunication…

The dpssl module controls the laser with a single line. This is the pwm, when it goes high the module turns on the laser.

DSP controllers use two lines. IN on the lps determines the output current limit for lps and is controlled via the pwm generated by the controller…

The other line is laser enable, this output tells the lps when to lase the tube.

On a dpssl type or most of the grbl type controllers there is only one control line…pwm…

You have to get pwm and laser enable into one control line …

You’re not the first, so don’t make it more complicated than need be. RF excited lasers are quite a different animal. Neither co2 nor rf work like the dpssl interface.



A few things to consider:

  1. I don’t think OP is talking about DPSSL lasers, sounds to me more like a commodity diode laser.

I don’t have a problem with these statements.

This is also fine with a nuance. It’s simply the presence of a non-zero PWM that signals laser on. In other words, the diode laser will fire for all non-zero duty cycles of PWM.

RF works differently to glass tube lasers. L-On is disabled for RF function and only provides PWM which is why it may be analogous enough to diode laser function for this to work properly.

The part I’m not certain about is whether or not PWM goes to zero during traversal moves on the Ruida. I assume it would need to if L-On is disabled during RF function.

Interesting idea… I have not gone down this path with the Ruida… there’s probably lots of paths I haven’t gone down…

Looking at the manual they don’t say anything about the l-on when associated with rf machines.

I would have to think the pwm would have to go to ground or it would be lasing.

Apparently, I’ve been told they can lase at very low %… I could never afford one, but once I stood next to one and found out how deafening it was… not sure I’d really use it.

The diode or tube/lps?

If I get off my bottom, I’ll change mine to RF and hang the scope off it and see what it does with the pwm and how L-On reacts…


Take a look at this. This is from the manual for the 6445.

This makes sense to me.

Not tube/lps. The signaling function of diode laser module.

Nothing like some practical footwork.

I know it states that, as long as it doesn’t become unpredictable

Some simple tests should show us what it’s doing…

I’ll try some slow speed engraving of a few circles so it will have to turn off to transverse to another object… should be apparent.


1 Like

This has become way more technical and interesting than I’d imagined :grin: honestly some of it is over my head, but that’s what Google is for!

Might check out this thread.

Here is what I found out, thanks to @berainlb suggestion…