Good Day All,

I wonder if I can get some help.

Currently running as copper job using 3/8" thick, 1 1/2" wide and 75mm long C101 copper. Having to mill the part down (pretty simple features) with a thickness tolerence of +/- 0.05mm.

I run op 1 doing a face op with a 6mm 3 flute cutter (face off 0.5mm followed by a 0.1mm finsish pass), followed by milling the outside rectange profile with the same tool, and then a small shallow pocket in the middle of the part (around 1mm deep) with a 2mm end mill (it has internal rads that need the 2mm cutter size). Also a couple of tapped holed.

I then flip the part over to simply face off the opposite side to achieve the thickness. Im facing off about 3.5mm, hitting it in one roughing pass of 3.4mm then a finish pass of 0.1mm.

Im finding that when I take the parts off to inspect, I see them bowing. This in turn throws the part out of tolerence.

Can anyone help with the reasons to why it is doing this, and any ways to prevent it or improve it to hit the tolerences required?


I am using Aluminum 3 flute, uncoated cutters by the way.

Thanks

Rusty