I kind of pride myself in how meticulous I am with tightening my collet. I make sure it’s tight then I tighten a bit more. Tonight was obviously the exception and proof that it can happen to anyone.
I started my 3D finishing carve on a cribbage board around 3PM. Vcarve said 2 hours carve time, and it’s estimate was dead on accurate for the roughing. This carve ended up going almost 6 hours! I need to tweak my GRBL settings and Vcarve settings. Other than the longer time, that carve went without a hitch. Switched collets and bits to a 1/8" drill mill. Drilled the holes…no problem! Switched to a 1/32" bit for some detail decoration…no problem! So now, it’s time for the cutout toolpath. I bought a new long reach mill just for this job. I put it in, tighten it up to what I thought was enough and away to carve. Not 4" in, things start going bad in a hurry. I slam the Estop, everything stops and I survey the damage.
The bit is buried in the wasteboard but still slightly in the collet (it’s a long bit). I manually moved the Z up to get to the bit and board.
The board had started to move but was luckily stopped by the screw holding the clamp. The bit didn’t quite go through the whole design and I think I can salvage this (just gonna cut it straight across with the chop saw).
So a total of about 8 hours of carving was semi-ruined because the collet wasn’t quite tight enough.
Needless to say I was pissed. Not only did the 3D carve take forever but then something small and stupid on the last step screwed it all up. I wish I could blame it on being tired but that really wasn’t the case. Maybe the really big bits need just a little more torque or I just missed it.
The good though is I didn’t get hurt and the machine was basically not damaged.
The board started at 1.112" and the main surface was at 0.75" but I had 3D elements up off the 0.75", so the Finishing toolpath did the entire 15" x 6.625" surface.
Now, I had the board aligned parallel to the Y axis but was rastering in the X direction. Approximately 2540 passes. After every other passes (it’d go down and come back), the Z would raise to 0.5 inches above the surface (traveling approximately 1") and then back down. That added about 3 seconds to each pair of passes. Quick math shows that alone added an hour to the carve time.
The design had a carved texture model and so there was a lot of up and down on every pass. My accel was still set to the Inventables stock accel value. I’ve got the upgraded axis so I need to double that value (which I believe you did and we have the same axis).
This was my first actual 3D carve so definitely learned a lot. I really wish that something so simple had not caused this.