Problem with cutting plastic


(Frank Buss) #1

This is how the ball cutter looks after trying to cut some plastic:

plastic

It was quite hard, but I could remove it with a knife. Tool: Nomad Ballnose, 0.063" diameter. Standard setting in Carbide Create for ABS: depth per pass: 0.227 mm, stepover: 0.714 mm, feedrate: 302 mm, plungerate: 75 mm, RPM: 4687.

I guess the ballnose cutter is not a good idea for plastic?


Newbie: best way to drill some holes in a case
(William Adams) #2

You need to move the machine fast enough to maintain an adequate chipload, and spin the endmill slowly enough that even when it slows down into a corner it won’t overheat and begin to melt the plastic.

See https://precisebits.com/tutorials/calibrating_feeds_n_speeds.htm for a testing technique

You’ll also want to clear out as much as you can using conventional endmills — just use the ball where needed for undercuts.


Best method to cut this?
(Byrne Pedit) #3

Here’s a link to WIll’s Feeds and Speeds chart which helped me cutting acrylic:
https://public.tableau.com/profile/willadams#!/vizhome/Carbide3DCNCFeedsandSpeeds/Sheet1?publish=yes

Most notable, your feed rate appears too low.


(Frank Buss) #4

Thanks, that’s a nice table! 9000 RPM and feedrate of 1000 works much better. Still sometimes some chips are spiraling at the cutter, but they don’t bake anymore and I can blow them away while it cuts.


(Byrne Pedit) #5

I’m rather new to the CNC world but I’ve been reading a bit. A number of experienced users recommend NOT blowing, claiming that small particles find their way into bearings, etc. and promote wear. I’ve taken that to heart and am vacuuming instead.


(system) closed #6

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