Just Getting Started - Setting up Mach 4 and Laser

[Trent]

I'm just getting into this, and haven't been through all of the discussions yet, but have watched the videos on Auggie. Before digging in too deeply, I wanted to see if anyone has followed the PoBlog and their suggestions as to firing a laser from Mach 4 using the OC Output on pin 20. Here is the reference: https://blog.poscope.com/mach3-mach4-la ... th-pokeys/

I'm already using pin 17 for PMW to the spindle, and the SSR1 and SSR2 relays for the enabling the spindle and cooling respectively. The approach to use pin 20, linked to the OC1+ pin, and the Laser linked to the OC1- pin. My overall preference is to use Mach 4 where possible and not get into Auggie if I don't need to.

So far, I've wired up the laser to power (24v), and that is working great. The 20 pin from the DB-25 connector is jumpered to the OC1+ pin and the OC1- pin is connected to the PMW pin on the laser.

Mach 4 is configured based on the suggestions in the blog link above. My expectation would be that this should work, but the next steps are unclear. I'll continue to review videos and discussion threads to see if I can figure this out.

Next I would expect that I could trigger the laser using M62/63 commands, along with motion commands to get it to work. So far, I've not been too successful in getting the Pokeys Diagnostic screen to show that OC1 is getting a signal.

If there is a different, easier direction I need to go, looking for some guidance. I do have a second Pokeys57CNC BoB that I could possibly use for I/O if that makes things any easier.

[Trent]

While not 100% what's going on, I was able to fire the laser from Mach 4. I think the next step is to figure out how to write gcode that puts it all together.

If I run this, there is movement as expected. Not yet firing the laser.

Code: Select all

M62P0
G0X2
G1Y2F100
M63P0
G0X4
G1Y4F100
M5
M30

But if I add M3 S1 in the mix, the laser does fire, but then no movement.

Code: Select all

M3S1
M62P0
G0X2
G1Y2F100
M63P0
G0X4
G1Y4F100
M5
M30

I held a board close to the laser and it did in fact burn, so I'm hopeful that I'm going to get this working somehow.

This looks to be progress. BTW, the Pokeys Diagnostic does not show OC 1 firing (enabled) when I fire the laser. Not sure if that is expected. But seems to be a step in the right direction.

[Trent]

Update: When I thought it wouldn't fire after adding M3S1, I was incorrect. Since it did not fire right off the start, I would hit stop. But then I let it go without hitting stop, and twenty seconds later it fired and move.

Because I had set the Spindle to Wait on spindle to stabilize at 90%, this was causing the delay. Unchecking that box in Settings for Spindle, the laser does in fact fire using M3 S1. I can adjust the power to SXX and get a good line. What I don't yet understand is the use of M3 vs M62/63, so will continue to read, learn, and hopefully make sense of it. I've read a few things about CV Chain, but thus far that makes no sense to me.

[ArtF]

Hi Trent:

All a good plan, using Mach4 since your using it already is a good idea to keep complexity down. Auggie does more with lasers, but is complex to get going if your not used to it. I cant help personally much with Mach4's use as I've never used it, but it sounds by post 3 that your getting there. I think
its just am matter of the M commands in the Gcode being proper.

Auggie works differently, it assumes a g1 is laser on and a g0 is laser off condition, which makes it easier to use any normal g-code. Auggie also adjusts power during motion as a function of speed so you dont use m commands for it, just g0 or g1 and S sets the power when at full speed commanded of feedrate. Tweakie is a good person to ask on this for Mach4 as he has the most experience, if he isn't here , try the Mach4 user group, he's usually found there in the laser topics.

Art

[Trent]

Thanks Art. I’ve seen a lot of posts by Tweakie in the Mach support forums, and reading up on the use of M3, M62/63. He’s posted at least one post processor for metric, and a test file. I’m seeing how those commands are working, so I may be able to get this working pretty easily. G0 moves are used with M63 to stop firing, while M62 is used with G1 moves, to restart firing. So it is starting to make sense to me.

[tweakie]

Hi Guys,

I gave Mach4 my best shot over the years but having the development of the Trajectory Planner and the Motion Controller under different roofs got the better of me in the end.
Like many of the original, long time, Mach3 users I eventually migrated to UCCNC and my first post on the CNCdrive forum was answered by “What took you so long to get here?”

Its off topic, but just as an example this was raster laser engraved using UCCNC and it would not be possible to do it with Mach4.

Tweakie.

[ArtF]

Hi Tweaky:

Nice to hear from you. Ill be honest, I hadn't heard of UCCNC , I had to go look it up.
(That's how isolated I am from CNC these days.. :) ). It looks like a very nice program, reminds me of Mach3 in
some ways in the old days when PP was king. Nice engraving by the way...

Glad to see your still engraving away..
Regards
Art