Broken R8 Collet ???

[Ulma Doctor]

i had a first at work today.....




a 1/2" R8 collet was broken, i didn't notice until i removed it.
i had no idea it was broken or how it got broken
all the normal things were considered, there was no heavy load on endmill being held in the R8
i didn't do heavy milling before the breakage.
the tool was a 2 flute endmill being used on aluminum with .020" doc's.

this is a new one to me!

 

[Aukai]

Stuff (SHI)happens, any idea on number of cycles?

 

[Ulma Doctor]

Stuff (SHI)happens, any idea on number of cycles?

at least 100 times in an out, i gotta figure

 

[Aukai]

That would SEEM like a non issue at ~ 100. I'm wondering about the collet having had to move too much to conform to tooling, or the collet out of spec, or worn? Spit balling I don't really know these things

 

[erikmannie]

Maybe somebody installed the collet in the machine with nothing in the collet. This would be rough on the collet if the machine had a power drawbar.

Just a wild guess!

 

[Nutfarmer]

The temper was off.

 

[middle.road]

Or perhaps someone had dropped it one time or another...

 

[kb58]

Highly likely that the fracture started at the inside corner of the inside cut. If so, a radiused cutter would have likely avoiding that.

 

[higgite]

Mike, that's what you get for buying a Popiel Pocket Collet Kit. That's what happens when you don't use enough glue to attach the fingers to the shank. You should know better.

Tom

 

[benmychree]

Chineseium?