1-1/2" Milled Pocket 6061

[stang5197]

I need to mill out a pocket that is 1-1/2" deep in 6061 aluminum. The pocket is approx. 5.25" long and 2.5" wide with large radiused corners (see attachment).

I am concerned about the finish of the pocket, how would you recommend machining this? Machine is a Haas VF0E.

Here was my taughts:
Held in a Kurt Vise rough out the center pocket leaving 0.015" all the way around and using the same tool make a finish pass to clean it up.

Tool would be 2 flute Carbide with a 1-3/4" flute length. My concern is chatter with the long e.m. and also the corners when changing from climb to conventional milling.

Any suggestions would be appreciated.

[msomerville]

Originally Posted by stang5197 I need to mill out a pocket that is 1-1/2" deep in 6061 aluminum. The pocket is approx. 5.25" long and 2.5" wide with large radiused corners (see attachment). I am concerned about the finish of the pocket, how would you recommend machining this? Machine is a Haas VF0E. Here was my taughts: Held in a Kurt Vise rough out the center pocket leaving 0.015" all the way around and using the same tool make a finish pass to clean it up. Tool would be 2 flute Carbide with a 1-3/4" flute length. My concern is chatter with the long e.m. and also the corners when changing from climb to conventional milling. Any suggestions would be appreciated.

I don't think you will have any problems at all. If you are cutting the same direction how is it going to change from climb cutting to conventional? I am not familiar with you machine, but this should be a walk in the park for you. I would use a 3/4" diameter tool and cut it just the you described.

[neilw20]

I think 0.015 is way too much for finish cut.
Using 4 flutes on the finish cutter, and running cutter slow enough that it doesn't resonate. Try to to keep the feed rate up on the finish pass. 4 flutes should give nice overlap. Going all the way anti-clockwise around will be climb milling. How can it not be? Main problem is selecting approach/depart point. Make sure you change the feed rate going around the ends, so that the cutting edge sees the same advance size per flute. Reduce by ratio of radii I think it is.

[big_mak]

I'd use this gorilla mill 1/2 1-1/2 4.0 GMA12FL3
http://www.gorillamill.net/nonferrous.html
I use em, and love em!!! You can use the same tool to rough and finish. Use a spiral out type tool path, and you will be fine.

[stang5197]

Thanks for the info.

big_mak I will check into the gorillamill endmills, I am a big fan of the Niagra stuff but always looking for cheaper/better end mills.

We have some new Niagra HSS TiCN 3 flute endmills here that are 0.75" diameter 1.75" flute lenght.

According to Niagra they recommend 3210RPM and 72IPM when running at there recommended 630SFPM and 0.0075" FPT. The axial depth would be 0.375

Do the feed and speeds look right for HSS? The RPM seems too low

Also the cam software is not compensating for the radius in the pocket, is that critical?

[big_mak]

R-Comp in the post is all dependant on the tolerance in the pockets.

[DareBee]

Originally Posted by stang5197 Thanks for the info. big_mak I will check into the gorillamill endmills, I am a big fan of the Niagra stuff but always looking for cheaper/better end mills. We have some new Niagra HSS TiCN 3 flute endmills here that are 0.75" diameter 1.75" flute lenght. According to Niagra they recommend 3210RPM and 72IPM when running at there recommended 630SFPM and 0.0075" FPT. The axial depth would be 0.375 Do the feed and speeds look right for HSS? The RPM seems too low

IMO those are high end #s
3200 is flyin for HSS and .0075 is an aggresive feedrate.
You may want to keep your hand on your overides and start in easy with those settings.