Laser questions



  • Hello there, I tried looking on here for some information about running a laser off one of the fan ports. I'm trying to have a multi function machine. I've not yet purchased my extruder setup fully so I was tinkering with the laser I have. I currently have this laser - https://www.aliexpress.com/item/5-5w-high-power-450NM-focusing-blue-laser-module-laser-engraving-and-cutting-TTL-module-5500mw/32559183201.html?spm=a2g0s.9042311.0.0.3al7jE
    and was trying to run the gcode out of inkscape using this really cool plugin - https://github.com/305engineering/Inkscape anyway, so I'm not sure if my issue is with the laser not turning off or me just not getting the settings to be correct. I'm new to the plugin and could have the settings incorrect. Though I've tried adjusting many things getting the same results which is why I think it's the control of the laser. So Tech2C had a video using this plugin and when he ran a greyscale selection his laser in the video would "pulse" it would only turn on like a dot matrix style printer. burning the image on your material as it passes by. Now when I tried it on my machine, the laser would not fully turn off. I'm not using the same laser as he is. Not using a ramps board like he was either. I am assuming the laser isn't turning off quick enough because I can see the slider on the web gui for fan0 moving around for different power strengths but the laser physically stays at the same power until there is a long enough "pause". My setup is a 24v system with a 24-12v step down going from the fan0 to the laser module.

    if you need to look at the gcode from my design, let me know. I'll upload it or whatever. I sure as heck don't know how to read it that well but am learning little by little.

    Thanks,
    Curtis


  • administrators

    How have you connected the laser module to the Duet? Does it have a separate input for turning the laser on/off without switching the power?



  • @dc42:

    How have you connected the laser module to the Duet? Does it have a separate input for turning the laser on/off without switching the power?

    The module or controller. Not sure what it's called has 12v in which is connected to the stepdown and from stepdown to 24v PSU laser fan and diode are connected to the module.


  • administrators

    As well as the 12V power input to the module, there should be a signal input (typically accepting TTL signal levels) for turning the laser on/off. It's best to use that input to control the laser, not to switch power to it, or to switch power for safety only but in normal operation to use the signal input to control it.



  • @dc42:

    As well as the 12V power input to the module, there should be a signal input (typically accepting TTL signal levels) for turning the laser on/off. It's best to use that input to control the laser, not to switch power to it, or to switch power for safety only but in normal operation to use the signal input to control it.

    If I use the TTL plug, going from TTL to fan0, the laser never turns off. it will always stay on. I've got the jumper set on the fans to 5v, if I put the web gui fan control to 0-100, I see no change. Right now I have the stepdown set to 5v so it's going psu to stepdown 5v out to the module. There is a guy who's also going through the same issues on the Hevo facebook group.



  • ok so now that I'm home, I unplugged everything and plugged it back in and now it works.. TTL plug connected to fan and in the UI I can turn fan on and off controlling the laser. I'm still having an issue with the laser not turning off and on like it did in Tech2c's video.. not sure why that is


  • administrators

    @gnatman:

    ok so now that I'm home, I unplugged everything and plugged it back in and now it works.. TTL plug connected to fan and in the UI I can turn fan on and off controlling the laser. I'm still having an issue with the laser not turning off and on like it did in Tech2c's video.. not sure why that is

    Please explain in more detail the issue you are having now.



  • I'll do my best to describe whats going on. In this video you can see tech2c use the plugin I'm using.
    https://www.youtube.com/watch?v=BErBHOE05vg&t=3s
    I'm doing the same settings as he is for the airplane portion. I load my image into inkscape, use that plugin to make the gcode and then upload it to the duet. This is what happens.. https://youtu.be/KW2MdKNNeU8
    in my video the laser I would assume should be turning on and off. I show the image Im trying to make in inkscape picture I found off the internet and then I show the web gui. I'd expect the fan to be at 0 as the laser should only be turning on when it hits certain points like it does in tech2c's video. I did see the fan speed move a little bit but it never goes off fully. Not unless the gcode finishes or is canceled.

    Again this could be an issue or setting in the plugin but thats what I don't know.


  • administrators

    I have added this to my list of things to look at, however due to other development work at present I have a backlog of 6 items, so it will be a few days before I can look into this.



  • Thanks I appreciate your help. You've got all my other issues squared away. I look forward to your reply



  • Hi gnatman,
    Please can you check G code files that was produced from Inkscape. Especially you should check M05 S0 lines. If you see previous two line from "M05 S0" line exactly the same, your problem is same with me. I think there is a firmware problem. I have same problem and i removed one of repeated line and laser turned off normally.

    Thanks
    Cafer



  • @cgcafer:

    Hi gnatman,
    Please can you check G code files that was produced from Inkscape. Especially you should check M05 S0 lines. If you see previous two line from "M05 S0" line exactly the same, your problem is same with me. I think there is a firmware problem. I have same problem and i removed one of repeated line and laser turned off normally.

    Thanks
    Cafer

    My gcode is full of M106 and 7 commands. Like the lowest I see though is M106 S3 never an S0


  • administrators

    It sounds like that gcode file expects the laser to be controlled by the Fan0 output then.



  • @dc42:

    It sounds like that gcode file expects the laser to be controlled by the Fan0 output then.

    Correct, which it is.. I've the a 2pin plug in the TTL from the laser to the fan header and it's jumper set to 5v I can control the laser, I can see the plugin works up to a point.



  • I still haven't been able to figure this out


  • administrators

    Does the gcode file contain duplicated G1 command lines as cgcafer suggested it might?



  • Here is just a tiny bit of the code

    ; Generated with:
    ; "Raster 2 Laser Gcode generator"
    ; by 305 Engineering
    ;
    ;
    ;
    G21; Set units to millimeters
    G90; Use absolute coordinates
    G92; Coordinate Offset
    G00 X0.0 Y0.0
    M106 S0
    G01 X43.5 Y0.0 F1000
    M107
    G00 X43.5 Y0.1
    M106 S0
    G01 X0.0 Y0.1 F1000
    M107
    G00 X0.0 Y0.2
    M106 S0
    G01 X43.5 Y0.2 F1000
    M107
    G00 X43.5 Y0.3
    M106 S0
    G01 X0.0 Y0.3 F1000
    M107
    G00 X0.0 Y0.4
    M106 S0
    G01 X43.5 Y0.4 F1000
    M107

    I have uploaded the gcode to my google drive if anyone would like to take a look at it.
    https://drive.google.com/open?id=1N1VRtA-BgVCqSdx-f-GF5k92AtwygxuN

    Thanks for your help dc42, next thing to order after april will be my dual nimbles.


  • administrators

    1. G92 with no parameters does nothing.

    2. M106 S0 and M107 both turn the fan (or laser on your case) off. So in that snipped of code, the laser will never be on.



  • Correct in that little bit of code, the laser is off, after playing with it more and using different images. I think it was doing what it did due to the image. I did some searching and found a guy using the same plugin with another board and was getting some really nice results.
    Thanks for your help everyone.


  • administrators

    So do you have it working now?


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