Re: Milling D2 Tool Steel
For roughing D2 you can't go wrong with negative rake ceramics as long as it's not an interrupted cut. No coolant or you'll get thermal shock that will shatter the inserts very rapidly~
I ran my 2" facemill at 2,200 rpm, 50-100IPM at around .030"-.045" DOC. I've run it as deep as .250 deep at around a 10-20IPM but if the inserts go out you wreck the hole cutter instead of $20 in ceramic discs.
I've literally machined several tons of D2 at 61-63 Rockwell with this setup and the only problem I've ever had was catching my VMC on fire twice~
Ceramics like smooth interrupted cuts but even when I've had to machine down recycling blades that had interrupted cuts along the perimeters, I'd just watch for the chips to start turning brighter orange and then rotate the inserts.
I'd get on average 20 cutting edges per insert x4 inserts. I would average roughly 24 cubic inches of material removal per set of cutting edges. Inserts were $10 a piece, so for $40 I could remove around 480 cubic inches of material. I had a little over $1,500 into my CAT40 holder, retention stud, Ingersol Rand facemill and inserts.
The finish with new inserts is good enough to see your reflection pretty decent.
This cutter works so good in D2 that I was able to charge over 4 times my regular hourly rate.
Be careful though, it will burn the wipers off of your way covers and catch anything around it on fire!!!
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