Just built an OX CNC and love working on it. I is doing something strange after switching to LinuxCNC. I have managed to get the everything tuned, but when it cuts the inside of a square it has this little jag in the corners. Any thoughts on the cause? The machine is cutting clockwise and the spindle is rotating clockwise. Attached is a picture of the issue.
My machine does exactly the same thing when entering the wood. Does not do it on corner two, three or four. Very frustrating.
I get it when doing the pocket in single or multiple passes. Thought is might be runout on the spindle, but that does not make sense otherwise it would cut wider all along the pass.
It may be a cutter compensation issue. cutter compensation is a mode (modal) command. To switch to that mode a g1 linear move longer than the offset must be issued. This sounds like your issue Dave. You may be picking up your offset in the cut. check your code for this. If you are then it's a simple fix...program it to pick up the offset on the way to part home prior to the cut. If the error is through the full depth of pocket on multipass then it might be dropping comp and picking it up again though this is unlikely and is a CAM issue. Check the code for this too. With all the controller and CAM combinations it can be tough to diagnose certain issues that may be program specific if you don't use the same program. I think CDHU may be having an issue with motor acceleration through corners or a roll through corner issue. It could be the control or the cam program or a combination. Heck, its possible it's mechanical. I don't use linuxcnc or his cam prog. so it's tough to say. Good luck guys. Joe
Hey Justin. That picture is CDUHs and the post you quoted is Dave's. Dave says he does have a problem with corners 234.
I am cutting pockets to test the X and Y distance. Yes the jag is in the top left and bottom right. The cut is a pocket that spirals out of the center with the transition to the next step in the lower left corner. I was playing with it tonight and was watching the code and on thoughts two corners it looks like there is a jag in the code. I am using Vcarve Pro 8 with the LinuxCNC mm post processor. I was thinking of trying generic post processor to see if it made a difference. I am not sure if it makes a difference, but I have LinuxCNC controlling spindle speed. I will try the cut counter clockwise and let you know. Originally I was running GRBL and EASEL to drive the CNC, but now I am trying to make one of Brian Law's clocks so needed a little more control.
please can you try a simple square with Gcode generated using Sketchup + Sketchucam. actually, let me give you some code to try.... simple 50mm square, 10mm up and right from x0,y0. 6mm material, 3mm bit Code: % (Generated by SketchUcam V1.3b-64f6) (Bit diameter: 3.0mm) (Feed rate: 1000.0mm/min) (Plunge Feed rate: 750.0mm/min) (Material Thickness: 6.0mm) (Material length: 2500.0mm X width: 1200.0mm) (Overhead Gantry: true) (Optimization is ON) (www.PhlatBoyz.com) G90 G21 G49 G61 G17 M3 S30000 G00 Z5.000 X8.500 Y8.500 G01 Z-6.000 F750 X61.500 F1000 Y61.500 X8.500 Y8.500 G00 Z5.000 (EndPosition) X250.000 Y250.000 Z32.000 M05 M30 %
Yeah. Dave's the swarfer is right CDUH. Check the machine and control software first. Then go on to v carve.
Just a thought...I took a closer look at your picture and it appears that the same thing is actually showing up in all corners. I would check to see whether your machine is either out of square or needs to be calibated.
