Pocket NC power limit

I’ve been doing some machining on the Pocket NC lately to prototype some “design for manfacturing” improvements. Some time ago Q at Pocket NC posted that early versions of the v2-50 had a spindle power limit that they later decided wasn’t necessary. My v2-50 was pre-ordered at the launch, so had said limit. There was a procedure for removing it in later versions, which just required removing a single SMT resistor.

WOW! What a difference!

I’ve iterated such that with 4mm single flute tooling and the spindle extension, I was no longer having tool pull out issues, but the maximum MRR (material removal rate) I could achieve was still somewhat limited. My best recipe had 4mm step downs with a 0.2mm width of cut at 750mm/min (about the maximum speed of the Pocket NC). Given that in 6061, I basically always run at that 750mm/min, I measure the MRR as the cross-sectional area, or in that case 0.8mm^2.

With the spindle resistor removed, I’m able to get up to 2mm^2 cross sectional area! In practice, I’m mostly doing 1.6mm^2 to give a little margin, but that is still twice as fast. Granted the Pocket NC isn’t designed as a high speed VMC, but when I’m running parts that have an 8 hr machining time, getting those down to 4hr is a big win.

At this point, other things are the limiting factor. The stock enclosure I have needs emptying every 20 minutes of machining, and when removing large amounts of material across the full work area, you have to clear chips nearly continually from the X axis to keep it from blocking travel near the edge when the chips are flying in inconvenient directions.

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