Pocket machining question

[Pat]

I am sure this is a basic question, but I would like to know if there are several methods to make this pocket. Say you have 3" square pocket .75 deep with .50" fillet all around the bottom. Would you just use a CNC, a .50" ball endmill and program a small stepover or go with a flat endmill first and then do the fillets. Then you have to clean out the small sections in the corner where the flat and ball mills didn't get.

Have I answered my own question here?

Thanks,
Pat

[Ken_Shea]

Whether CNC or manual, you would want to go with the .5 end mill first leaving sufficient material for the ball nose to complete the bottom radius. There should be no need to re-mill the entire pocket with the ball just the outer walls to the floor.

[CNCgr]

Yes, Ken_Shea is right.

Originally Posted by Pat Then you have to clean out the small sections in the corner where the flat and ball mills didn't get.

What do you mean? The vertical corners? If you want something to fit tight in the pocket (so you want no fillet at the vertical corners) it would be better to drill the corners first. See the attached pic (I didn't include the bottom fillet).

Or mill 1/2 endmil diam past the corner.

[Pat]

Attached are 2 images from Solidworks. What they show is a section thru a pocket machined with a .50 dia endmill and then the corners with a .250 ball endmill. The tip of the ball mill does not follow the sharpe/square bottom corner of the first pocket. The ball mill does a .125 radius at the corners and leaves a little raised area at the pocket bottom. I think I would have to match the flat endmill to the radius of the ball mill to not get what the picture shows.

Pat