Climb Milling, I Knew Better

[terry_g]

I was shaping a crankshaft counter weight for a small engine I am building.
I was taking light cuts with a 1/2" end mill. I decided to try to take a light cut while feeding the mill
table back .002" "climb milling".
Wow way nicer finish. I did this a few times then I tried an .005" cut climb milling.
All was well for the next few cuts then there was a loud snap from the end mill and from the sound I could tell the mill was dull.
Upon inspection a cutting edge broke off and pieces from it dulled the other three edges.
A quality Niagara 1/2" HSS mill too.
I fairly sure I can sharpen it wit my hill-billy grinder.

Terry

 

[Brandon]

Virtually all CNC's routinely climb mill, but the ball screw and drive motors eliminate all backlash. Backlash is what destroys cutters when you climb mill. You also need to use your power feed. I tighten up the table locks just enough to create a slight drag to try eliminate any backlash.

 

[Pacer]

Climb milling is a useful method for getting a very smooth finish, but care must be taken, The non moving axis should be locked and the moving axis with a slight drag on it, the feed is best done with power, but if dont have, a careful steady hand feed is needed

 

[PurpLev]

I climb cut on 2 occasions:

1. to take an extra bite off of the material when on the return path (.005-.010 depending on depth of cut)
2. a finishing cut (0.002-0.005)

you want to make sure the other axis is locked in to minimize side-to-side movements on the cutter. you also want to make sure your climb cutting doesnt start halfway through the part (after conventional cutting ends) as this will present with the shock of the backlash into the mix.

other than that, your photo shows the end of the endmill. the climb cutting action usually refers to the side milling operation as this is the side of the cutter that grabs the material and tries to 'climb over' causing the material to be yanked by the cutter.