(Reworded and reposted with a better subject) Hello fellow carvers! First time poster, new'ish to the world of CNC. I have an extended 1515 machine with a Makita Router. BlackBox X32 is driving the machine and I'm using OpenBuilds Control to surface a spillboard with a 22mm surfacing bit with a 1/4" shank - in this case I'm using a sheet of polystyrene because it's cheaper than wasting wood - I originally found this problem with wood. There are no third party parts on the machine other than a dust collection skirt. Issue : - Each pass has a ridge at the beginning of the pass on the x-axis. - The plunge depth is correct, but as the machine starts to move on the X-Axis it appears to raise the Z-axis about 2mm (gradually) for a few inches, then drops it back down to the correct depth again. - This happens at the beginning of each pass, but does not happen at the end of the pass. - This is consistent whether I'm running a file from V-Carve or OpenBuilds Cam / OpenBuilds Control. - This also happens running jobs that are non-surfacing. Picture attached showing the ridge / hump I am describing. The other pictures shows the whole sheet, and the humps are staggered for each pass - i.e. the hum occurs at the beginning of each pass. I've checked all screws that I can find, GRBL $1=255, Z max feed rate is 500mm and Z acceleration is 150mm / sec (found these suggestions on another thread describing a different but somewhat similar problem. I offset the start point on the job 200mm on the X-Axis and the same problem popped up in the middle of the sheet, so it's not related to bows in the rail or something like that. It is not coordinate specific.
Hi Adam, there was a very similar post a couple weeks ago and he found it was the dust shoe bristles lifting the z axis at each direction change. Another common cause of this can be a loose lead screw, make sure the collars don't have any play. Cheers Gary
Oh. My. Goodness!!! Correction implemented - the culprit was stiff bristles on the new dust shoe pushing the Z-Axis up at the point of direction change. Thank you so much for answering my question
