Hello all,

First of all, please take it easy on this Newb. Ive posted questions before (on another forum) only to get slammed with condescending remarks.. thats not really fair and makes some of us not want to contribute.

So I need some help please.

Im running a DIY CNC with the following setup: DQ542MA drivers, NEMA23 motors (Y&A slaved), Breakout board, Mach3 (of course). I originally had this setup with a router and Im trying to convert to a laser. I can easily switch between the 2 by changing out mounting plates. The Laser i bought is a Chinese 3500Mw with a driver board which includes TTL.

I hooked up the laser TTL input to pin 17 on my Bob, and Ive got it to manually switch on and off by using the mist control and also the spindle. I guess my first question is if Im to use a specific code to switch this off and on do I have manually edit the G-Code and insert the correct M-codes? Is there some software out there that will automatically insert the correct code? Ive been using BobCad without much success and Im fiddling around with a couple others. Im good at the building part but lack some knowledge with the software aspect of it all. If I use PWM and to switch the Laser on, what code is telling it to do so?

Ive read some of the posts Ive found via google none which really helped me.. Yet! I need a push in the right direction! And not over a cliff please.....

I guess Im confused as to where to go next... scrap heap maybe?  LOL

Thanks in advance 

So many questions.

Your TTL switching of the laser is probably best done by setting Output#2  to Port 1 Pin 17 then within the Gcode using the M11P2 command to switch the laser ON and the M10P2 command to switch the laser OFF. These commands can be automatically inserted into you Gcode by modifying the standard BobCad post processor (check with BobCad – they have already modified a post processor for someone else). The M11/M10 commands only take effect upon axis movement so they are fast acting and work well for me.

If you are looking at software other than BobCad then check out PicLaser http://www.picengrave.com/ also look at their methods of laser control etc.

Tweakie.

Thank you for the quick reply. What I should done before posting is to research the forums here. I did find some useful info.

I downloaded Inkscape with a LaserEngraver plugin and got it make a very generic g-code and I am using output #1 with pin 17. I did get it to fire on and off. Only thing is there is a dwell time as to when the laser starts up and then the machine moves, leaving a bigger mark. also transferring the G-Code  to the cutting machine and loading into Mach3 makes the G-Code do funky things like Add Circles and such.. well at least it fired off.. thats a start

Ill check into the post processor for BobCad.

Thanks again.

Only thing is there is a dwell time as to when the laser starts up and then the machine moves

That is the reason for using the M11/M10 commands - there is no dwell time.

transferring the G-Code  to the cutting machine and loading into Mach3 makes the G-Code do funky things like Add Circles and such

If you get the crop circles goto Config. / General Config. and change the IJ Mode then regen. the toolpath.

Tweakie.

Thank you Tweakie..

Im Making progress.