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QFN-16 breakout (3mm x 3mm package, 0.5mm pitch, 1.7mm pad)

A project log for Minamil 2dc: a minimal CNC mill

Each axis: ̶$̶5̶ ̶$̶8̶ $10 motor+lead screw, 3x LM6UU, 3x 6mm x 100mm rod, 1/8in hardboard, PC case screws

paul-mcclayPaul McClay 05/02/2023 at 21:340 Comments

Apparently "QFN" is a broad category and "QFN-16" doesn't mean much without parenthetical elaboration. The buried point: 0.5mm pin pitch:

That beats earlier 0.65mm "fine pitch" results.


Yes, the two top-left holes are a little bigger. Getting through the whole process without error eludes me. Defaults and scripting in the toolchain (mainly FlatCAM & bCNC) would help, but first efforts at that haven't yielded much yet. In this case, I (i.e. it) drilled all the holes with a 0.9mm drill (25mil * 2^0.5), then switched the drill for a 1mm 2-flute end mill to cut the outline, then watched it re-drill two holes before remembering to load the cutout file. Sigh. (Earlier I tried plunging holes with the 1mm end mill, which would save a tool change, and which worked until the piece where each hole got shallower as end of the bit got duller.)

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