corner rounding

[inthedark]

Can any of you gurus, give me an idea on selecting a speed & feed for a .1875 corner rounding cutter on 6061? Or just a rule of thumb?

My finish is coming out a bit rougher than anticapated. I know it can be smooth if applied correctly. I can find no documentation on this type of cutter.

Any clues would be appreciated,

I have done well with the other speed and feed info I have gathered, for using regular end mills. My finishes are nice and clean, and I am using proper approach and depart methods.

Thanks,
Kenny

[steele]

I only have limited experience with corner rounding end mills but generally I don't seem to be able to run them too fast. I suspect you're not feeding fast enough or there is something wrong with your cutter such as insufficient relief. I would run the cutter at a feedrate between .005 &.015" cpt & 10-20Krpm. Lay the profile out in a CAD drawing or blow it up on a piece of paper. You'll see that the quantity of material you're taking of is miniscule on a .1875 radius. If you're running dry, I doubt a standard cutter would have proper clearances.
Jim
<www.picopascal.com>

[Mortek]

I've run a .125(HSS) corner rounder at 8000rpm and 100 ipm with excelant results and finish. Tone it down just a hair for a .1875.

[inthedark]

I am running an 80's model Bridgeport Series II and have not ran the spindle over 3200 RPMs. The max is 4K but will not get near that due to the age of the machine I baby it.

Thanks for the input,
Kenny

[HuFlungDung]

Climb mill, too. Its important.

[inthedark]

Hu, can you elaborate on that?

thanks

[Mortek]

figure about a .003 chip load per tooth. So if it's 4 flute at 3200 rpm try 38 ipm. Climb milling is going clockwise around the outside of a frame with clockwise spindle turning. Conventional milling is going counterclockwise around the outside of a frame with clockwise spindle turning.

[inthedark]

Ok, thanks for the tips, I will see how it turns out tomorrow. I was not familliar with the term "climb milling", thanks for the lesson.

Next day; I gave it a try and my edge is nice and smooth.



Thanks for the tips.

Kenny