Machining Polycarbonate - Nailed it!

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Machining Polycarbonate - Nailed it!

Post by John_TX » Fri Sep 09, 2016 4:02 pm

I've been fabricating electronic enclosures from those watertight gray polycarbonate boxes made by Hammond and Bud. In the interest of documenting feeds and speeds, here are my results:

Machining holes is easy - I've had great results:
Using a 2-flute 1/8" end mill, 40 IPM, DWP611 speed at 1, depth per pass 0.04", and following up with 2 finishing passes (one climb, one conventional).

Engraving text and logos was not easy! I had such mixed results - as soon as I got a perfectly clear logo and thought my settings were good, the next box would be a melted mess of fuzzy lines.
After researching here and elsewhere, I learned the key is chip production. Too fine a point on the engraver, and you're not going to break a chip out - at least not with the high RPM of the DWP611.
Without wasting your time telling you what I tried unsuccesssfully, here's how I got perfect engravings on polycarbonate:

30-degree engraving bit with 0.0118 tip (0.3mm) which are very cheap at amazon: ... UTF8&psc=1
Max depth 0.020". Depth per pass 0.020". Feed at 80 IPM. DWP611 speed at 1.

I hope this saves someone else as much time and effort as I spent to learn it!

Regarding finishing, I put acrylic paint in the engraving (it gets all over the whole surface, but you have to force it down into the engraving), let the whole mess dry, then use rubbing alcohol on a cloth to remove paint from the surface. This leaves a clean in-fill if you wipe carefully. I then spray on clear-coat.
Holes and colored text
20160909_102217.jpg (41.26 KiB) Viewed 840 times
Logo, before paint
20160907_103510.jpg (489.08 KiB) Viewed 840 times

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