Hello, I generate a simple Gcode on cam software (see attached). When I run the job on the CNC, the "feed" cursor displays at some point of the job a speed which varies rapidly from 0 to 100% (and the real speed of the CNCvaries too). I looked for a cause in the Gcode : and the instants corresponding to these "speed variations events" correspond to distinctly smaller segments in the Gcode (file "Gcode-posttreatment" attatched). I have two question: why does CAM generates these 0.0001 mm segments? (it is clearly unneeded: the shape is very smooth) How to prevent them from varying the speed of the cutting tool (which clearly degrades the quality of the project)? Best regards!
Whatever generated the shape has included some very short line segments. CAM just translates those into Gcode. Has your drawing program got a 'smooth' or 'filter' function you can use to remove the very short segments? and the reason the tool appears to slow down greatly or even stop at those points is because those very short segments also change the slope or direction of travel and GRBL has to stop to go 'round the corner'. for example these lines Xdist Ydist length slope 0.2431 -0.2533 0.351082 -1.04196 -0.0001 -1E-04 0.000141 1 0.244 -0.2486 0.348336 -1.01885 you can see that the slope changes from -1 (moving down to the right) to 1 (moving up to the right) which is a ~90 degree shift. GRBL cannot power smoothly through 90 degrees (-:
Thank you! Good explanation! Ok, I have to find the origine of these small corners. My vector shape is smooth and simple (illustator - bezier curves). I save it in.svg to transmit it to the cam software and the SVG seems smooth too... It could be the cam which does not understand the svg? I have a version of the SVG attached. It is a serie of cubic bezier curves: I do not see any segment in it... Maybe does the cam not read properly the cubic beziers? Nicolas
Not the free OpenBuildsCAM no, it only handles linesegments, so it has to convert beziers, arcs and curves. If you need better performance, consider alternative CAMs (usually licenced though): docs:software:overview [OpenBuilds Documentation] Or, convert your beziers to polylines in Inkscape/Illustrator, etc - were you have control of segment lengths, have simplification tools to remove unneeded nodes, etc: See docs:software:file-errors [OpenBuilds Documentation]
Ok, thank you for your answer! But the openbuild free cam seems to understand the cubic beziers... just these small segments to erase.. I am coding a small soft that erase the line of the Gcode corresponding to the small segments. It seems to work... Mabe it could be a good add on to your gcode generator? Thank you for your help and for this very intersting forum! Nicolas
