I have been using the same gcode to create american flags. I am using glued 2x4’s or 2x6’s as the blank. I’ve probably tried about 10 times and successfully created 4 because the machine doesn’t want to produce the same output every time. I have tried with a bit change… starting with a 1/4" ballnose and switching to a 1/16" bit for the finish path… sometimes that works sometimes it doesn’t. I have tried doing it entirely with just the 1/16" bit and letting it run for 3x as long.
Most recently, I tried just just running a finish path. No rough path. This was using the 1/16" bit. it started beautifully. At some point during the cut it shifted left. then a few passes afterward it shifted left again. My image shows where it was running properly and then where it shifted.
I have a mounted L bracket in place acting as the bottom left corner so the starting point is the same for every piece and I use my bit zero on every run. I don’t understand why the machine shifts like this mid cut. Has anyone experienced this or does anyone have any suggestions?
A finishing pass w/o a preceding roughing pass will result in the tool trying to move through stock which the toolpath assumes has already been cut — which would be disastrous with a tool which doesn’t have full-length cutting flutes.
You also should skip smaller sizes when going from roughing toolpaths to finishing toolpaths, so the order of operations to get from a 1/4" ball-nosed to a 1/16" tool would be:
roughing toolpath w/ 1/4" ball-nosed tool
finishing toolpath w/ 1/4" ball-nosed tool (in softer, more easily cut stock this might be skippable)
finishing toolpath w/ 1/8" ball-nosed tool
finishing toolpath w/ 1/16" ball-nosed tool
Please post your .c2d file and let us know step-by-step:
Also what machine is this being done on? If the Shapeoko Pro, I’d also suggest lubricating the bearing housing: CNC Machine Maintenance
Also I think this was covered on the support show (I think support show 2?)
I’ve looked at this maintenance document but i’m not sure how to lubricate the bearing housing. I asked support for some sort of image/video. Are you able to provide something?
The tool does have full length cutting flutes and i’m using 2x4’s and 2x6’s so it’s softer wood.
The person that I bought the STL file from mentioned that when he cuts them he doesn’t do a roughing path which is why I had tried it that way. it seems to cut just fine, the tool can do it, it just shifts at some point during the cut. not every time, some of the time. i dont know why i get perfect output once and the next run is garbage.
also i’ve found that if i have a tool change involved there are times when the bit setter doesn’t line up properly and it misses the button. or even if it hits the button when it starts to cut it starts in the wrong place.
You are describing lost steps. Check the machine mechanically and verify all the wiring. If all is okay on those fronts, look into feeds and speeds and chipload.
On each housing (there should be two per linear rail), and then inject some of the recommended oil using a syringe or a pipette.
Keep a rag handy, as the oil may leak out. You’ll need to do this more frequently for the X and Y axis.
