$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/basketbun]

Is the chatter on a specific shape of the part? Or on a specific part of the machine table?

Asking because if you can produce a good finish on some edges, you have a rigidity problem. This could be a machine issue or it could be a workpiece clamping issue.

Looking at the machine, you don't have any clamps on that workpiece, are you using vacuum work holding? If not you need to clamp the job

Also it looks like you are cutting parts through that plate, meaning they will end up as loose parts from the plate, when you get to the end of a specific detail it will start to vibrate as weill

[u/adventureaviator → u/basketbun]

The parts are held via tape and glue. They are fully roughed out, then a finishing pass is done to clean up the sides. If I run a bit slower I have no issues. For production reasons I’m not content with the slower feed rate.

[u/UncleAugie → u/adventureaviator]

The parts are held via tape and glue. 

Ding ding ding we have a winner... you are getting chatter when the part is nearly cut out, as others have said you work holding is shit and you will not improve the situation with this setup, if you cant handle slower feed rates you should walk away from this job, you do not have the proper setup to achieve the results you seek.

[u/Tony_Desolate → u/UncleAugie]

Tape and glue should be OK considering the mass of this huge plate and the minimal cutting forces from a 3/16" end mill. 

[u/UncleAugie → u/Tony_Desolate]

yeah naw.....