Thread: Helical Side Finishing Pocket Wall Aluminum

Has anyone ever done this? I'm having problems with a long 1/4 em pushing away at the bottom of a pocket. I was thinking of trying a helical finish pass so that the tool was pushing down in Z instead of just on the side. If you have tried it what were the results and what ramp angle did you use? The walls only have .002 left to finish but the pocket is always small at the bottom from the tool pushing...

How deep is the pocket? How many parts?


I use this technique a lot with severe length to diameter ratios and have good luck. I did some 2.500" deep pockets in 6061 a couple months back with a 1/4" reduced shank EM from MariTool. I think I used .003" radial DOC and took .050" in Z per pass. I had to drop the speed way down to about 1200 RPM to eliminate the chatter. It's not fast, but it works great for prototype jobs.

Originally Posted by coyotekid

How deep is the pocket? How many parts?


I use this technique a lot with severe length to diameter ratios and have good luck. I did some 2.500" deep pockets in 6061 a couple months back with a 1/4" reduced shank EM from MariTool. I think I used .003" radial DOC and took .050" in Z per pass. I had to drop the speed way down to about 1200 RPM to eliminate the chatter. It's not fast, but it works great for prototype jobs.

Pocket is 2.8" dp in 7075. 900 pcs. Right now I've found the best luck is with a 35* helix tool with 1.75-2.00 fl. 1.75dp per pass with a pass at .002 , .0005, and 0 from the wall. 5000 rpm 40ipm. The only problem is as it gets down inside the pocket it pushes away from the wall. Finish stays nice and rerunning the part a few times seems to be the trick... I need to get this automatic so i don't have to worry about the operators switching programs back and forth on the 5 axis. I've tried using a stub LOC relieved tool but couldn't get rid of the steps from each depth...

Use the stub length reduced shank and then tool change to the long flute end mill and take that .0005" pass, it should get rid of any step evidence and you won't have a bunch of taper already present and the walls should turn out a lot straighter.

I'm thinking of getting a custom 1/4 made on a 3/8 shank...