Hello, I am new to all of this so bare with me. Context: I am building a custom machine using the C beam XY gantry in conjunction with a 2x72 belt grinder (mounted horizontally with a contact wheel) to grind knife bevels. I am modeling the cut in fusion then creating a drawing of the exact XY path I need. I have then taken that DXF to DXF2GCODE (free software) and made gcode out of it. I've then imported that gcode into Openbuilds control to modify it. First I deleted all the z axis because this machine is XY only. That program worked but does not have any stepovers to gradually remove material, I manually changed the zero and walked the program in as a test. It works. Now I need a program that has all the correct stepovers. The gcode that DXF2GCODE gives me is G90 (absolute). I am trying to convert this block into G91 (incremental) so that I can copy it with the stepovers in between. The X Y conversion was easy but converting the I J values to R values isn't working as well. Issue: I have the correct R values from my Fusion 360 drawing, for some reason The open builds control is showing me the incorrect radii in the simulation. The pictures will tell the story better than I can. How do I get these G3 lines to do what I want? Screenshots: The Fustion 360 drawing is what I want the path to look like. The simulator with the bumps, instead of smooth connecting curves is what I'm getting out of Openbuilds cotrol. If you've read this far I appreciate you, any help with the radius issue is much appreciated. I plan to show the machine after I get it running properly.
why not let Fuision generate Gcode for you? it is very good at it and our postprocessor is tuned for GRBL controllers. You can just use the offset tool to repeat your line at various offsets then do '2d contour' along each line in turn. Set the heights offsets to the minimums you can get away with and just leave the Z commands in there, since no Z is connected they will be essentially ignored. Hand editing code is to be avoided. R format arcs are deprecated, they just don't work very well at all, on any controller. I would avoid them (in fact I have been avoiding them for at least 10 years when I reprogrammed all arc generation in SketchUcam to use IJ format) Then, even in IJ format, do not do more than 180 degrees in any one arc command. And do use enough precision in your offsets, at least 3 decimals in inch mode, 4 in metricmode, especially small arcs need to all the numbers to be very accurate.
David, Thank you very much for this advice. I was making it so much harder than it needed to be. Fusion to gcode works like a champ and I've been running and modifying the toolpaths for the last few days! I'll share the machine setup in the coming weeks. Thanks again!
