Basically new to all this. First off, not a computer person, through in a brain injury and a very poor memory as a result, i really dont know what im doing lol. Bought a used mpcnc a while ago and i am running fusion 360 with Guffys post processor. I used the machine a few times earlier this yr and it seemed to work. Now however, i create a piece that i am going to engrave. The simulation works normal, i post it and save it to my sd card. Run the machine, and it does its own thing. Its engraving something but it is not similar to what i programmed and not even in the same area of the board.
Hi stikman,
what kind of contoller software are you using? Can you see a preview?
Encountered problems with arcs multiple times, now. Can you check that?
If you can, please post a screenshot of your gcode preview.
I have fixed a version of the(EDIT: Guffy’s MPCNC GRBL) fusion post for those cases by removing plane selection G17-19 and always posting IJK coords for the arcs. Those used to be modal, which many (even commercial) controllers often have a problem with regarding arcs. That’s actually a quasi downgrade, making the post “less correct”, but it works…
At the moment I can’t seem to post uploads. As soon as I
Snoop’s potential fix is for a GRBL controller. Most MPCNC machines run Marlin. There are many ways your cutting could be going wrong, and there is not enough information here for me to figure out the problem. Take the g-code file in the SD card use a g-code simulator to see the path of the g-code. I’ve used the one here, but only because it was the first google search result. I’m sure there are other and better ones. To use this one, delete the sample g-code in the left window. Use a text editor to open your g-code file, copy and past it into the g-code window, and click simulate. The path on the right will tell you what path your g-code is attempting to cut. If it is not what you are expecting, then your problem is likely with the way you post processed in your CAM. If it is what you are expecting, then the issue is on the MPCNC end.
So is the problem you are fixing a GRBL issue?
Hi Robert,
basically, yes. Seems to be a problem with GRBL, or GRBL in conjunction with the software on the PC that’s feeding the GRBL controller(ESTLCAM for example).
I took the post from https://github.com/guffy123/mpcnc_posts_processor(that’s why I posted this GRBL post) a few months ago, and made the changes. But I’ve seen similar problems with modal coords and arcs on many controllers (Siemens 840D, Haas with original postprocessor from Haas, etc.), depending on who implemented the individual controller, if you ask me.
The original post is formally correct, and the basic design is better than any Fusion or HSM post I’ve seen from Autodesk, so far ^^