Hi, I'm currently building a laser cutter, and making great progress! Instead of copying a whole thread, if you'd like to know more about it, I've got a thread going here: http://laserpointerforums.com/f57/my-holiday-project-d-58283.html

Anyway, I have a question about using mach3 to control a laser. I have a 4 axis CNC controller board (Generic Chinese one), and it has a spindle relay. It works, however it only turns on when you start a program, and off when the program stops. I can see that the Z axis is what I actually need to control the laser, but I'm not sure how. Also having mach3 able to control the power thru PWM would be nice, however just simple on/off is fine as well.

I'm lost here, and very new to this, so any help would be appreciated

Cheers,
Dan

Hi Dan,

There is little point in using Mach to control the PWM as this is far better achieved with a seperate, external controller.
A simple circuit is all that is necessary to actually switch the laser from the Z direction signal (Z+(up) turns it off and Z-(down)turns it on). The actual Z movement needs to be small (0.001 or less) to reduce the time delay but editing standard GCode to achieve laser control is easy once you get the hang of it.
Have a browse through my webpage here http://www.cooperman.talktalk.net/files/27.htm this may answer some of your questions.

Tweakie.