Hey guys. On projects that i want to do a very shallow pass, whether its with a veebit, engraver, endmill, etc, the depth is off by about .02 to .04. example, i am pocketing out an area and i only want the depth to be .02 deep, with the max depth being .02 and the plunge rate being .015. The machine will start the cut at a depth of .05. i have used the bit zero and ive also zeroed out the z axis with a sheet of paper. Can someone please point me in the right direction on how to correct this problem?
Hi Trevor. I think more details would get some ideas from the forum. Can you post a c2d file or Gcode file from a cut where the problem occurred? Is this consistently reproducible or random? Has the machine always done this or has it just started recently? If it just started recently, did you make a change that coincides with the inaccuracy? How old is the machine / how much use has the machine seen? What material are you cutting? What toolpaths cause it, all of them? The initial depth is wrong on shallow passes but what if the pocket requires more passes, are they all inaccurate in depth, or just the first? Is the depth of the total combined passes accurate? Software version? Are these custom user defined tools or part of the library that comes with CC? Default feeds/speeds/depth of cut or user tweaked settings? Are deeper depths of cut also inaccurate? Any other concerns with the machine? Your experience level with the machine?
I know you want answers, not questions, but the questions above might result in good answers in return.
Cheers.
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Have you surfaced/leveled your wasteboard? Trammed your spindle?
I purchase the machine in november 23. When i first started, i thought that it was just an error in cutting parameters. My first project, i was trying to carve the stars on a union for a flag. No matter how shallow of a cut i tried, the first cut always started out around .015 deep. This was after I used the BitZero to zero everything out to the bottom left corner of the piece. It doesnt matter if I set the max Depth i want to cut to .001 with the depth per pass also being .001.
Today found the problem. After i probe with the BitZero, I went back and double checked the Z zero. I ran the dowel down to my work piece and when the dowel touched the piece, my computer said that dowel was still +.012 above the work piece. I tried to run the BitZero again and checked it. It showed the dowel to be +.013. So, with the Bitzero, its showing that the actual Z zero is .01 to .015 below the the top of the workpiece. g
I surfaced and trammed a couple of days ago. I thought that might have been the problem also. Its something to do with my BitZero not accurately registering the true Z zero. After running the probe, it keeps coming out to be off by .01 to .015. I mic’ed a piece of paper and ran the dowel down to the work surface while moving the piece of paper between the dowel and work surface. Once the paper felt resistance, I lowered the dowel the extra distance for the thickness of the paper (manually found zero). with the dowel at zero, the computer said that i was .012 about the workpiece. so the bitzero was saying that the Z zero was .012 lower than the material surface. i dont know how to fix that kind of problem whether its in the code/Programming. I Guess ill just have to manually input the Z zero from now on.
I have found that I don’t like using the dowel with the BitZero - it does not always register consistently when contacting the BitZero. I have no idea why only that I don’t like it.
Recently I have been using a 1/16in downcut endmill with the BitZero with very consistent results. I like how it takes more steps for it to find the edges of the corner hole of the BitZero.
But I also physically hold the BitZero in place on my stock - the unit has too little mass/friction to maintain position on its own. Even a little bit of strain on the cord can shift/tilt it.
Cleaning the dowels and Bit Zero will help. Added note, I do not follow C3D’s safety precautions on not holding the Bit Zero.
Mic your Bitzero and post the thickness. Someone here can verify what the correct thickness should be. I have never seen on the forum where this was a problem but it would be good to eliminate that as the source of the error.
I have an old third party touch plate I used with CNCJS macros but could never find a way to modify Bitzero code to use it with CM. I fully switched to CM a long time ago and now always zero manually.