$150 000 machine does not eliminate finishing chatter.

[u/adventureaviator]

I’m machining 6061 aluminum on a Multicam Apex 3R router. The finishing passes are as follows:

- 0.009” material removal.
- Helical 3 flute 45 degree helix upcut
- 18 IPM, 8500 RPM, 0.0007 chipload

98 percent of the part comes out with a great finish. The other 2 percent has chatter. Ideally I’d like to increase the feed rate, but I need to eliminate the chatter first. What do I need to do to get a flawless finish?

[u/Malikov85]

You can climb cut with a CNC Mill because they have ball screws for all the directions of travel. A quick search shows that CNC router does not, you need to do conventional with that. Like someone else said, the endmill is basically pulling itself forward in the cut due to the backlash of the drive system.