CNC Aluminum: Recommended Speeds/Bits?

[Bruceb]

Why do you use both up spiral and straight bits?

[JamesCH95]

Originally Posted by Bruceb

Why do you use both up spiral and straight bits?

Spiral bits are used for extracting chips from the cutting area. This is great for contouring holes, slots, pockets, and other features where chips tend to build up.

Straight bits, also called edging bits, won't extra chips as efficiently (or at all) but they also won't lift up on the part they're cutting. This makes them useful for trimming the edges of parts as there is plenty of room for the chips to go and they don't lift up on the part's edge, potentially causing chatter.

[Andy Brockway]

I have a really old CNC router with a standard wood router running at 30,000 rpm. I have had success cutting aluminum with an 1/8" diam straight router bit at 10 ipm, .005 DOC. This is slow but I do not run coolant and it does not clog the bit.

[sanddrag]

I have to post back in this thread to thank all those that recommended the Onsrud single flute bits. It's been a complete night and day difference. It essentially made the difference between our router not being able to cut aluminum at all, and now cutting it beautifully.

I was able to pocket with a 1/4" bit, 20,000 RPM, .090 DOC, 15% stepover, 84 IPM, and it worked very well.

Thanks again!

[Odin]

We usually use Onsrud 1/4 and 1/8 inch single flute with our feed rates being 60 ipm (1/4 in) and 35 ipm (1/8 in), a plunge rate of 15 ipm for both bits, and finally a spindle speed of 12000 rpm. This is all done on a techno router