New tool chatters.... easy way to dull end mills?

[InspirationTool]

I have an aluminum milling application where a new cobalt or carbide end mill chatters. After quite a few pieces (aluminum), the chatter fades. I assume this is due to the dulling of the edge and less "catching".

I'd like to get chatter free cuts from the beginning. Any ideas on how to dull the cutting flutes?

I am looking into getting some custom made neutral rake angle end mills made to help reduce this problem, as I suspect the long, thin, end mill is catching.

Thanks!

-Jeff

[Ken_Shea]

Jeff,
What about just breaking the edge with one of those diamond pads like 3M makes or similiar.




Ken

[InspirationTool]

Thanks Ken! I didn't know they existed. I'll look for them.

I also just realized, I could probably set something up with a granite surface plate, diamond dremel bit, and some gauge blocks. If I set the diamond surface a couple thousands over the center line I should have only a small amount of negative rake.

-Jeff

[Geof]

I have done it with very fine emery paper.Wrap it around a piece of wood and drag it gently down the cutting edge.

[InspirationTool]

Ever have one of those "I'm a freakin IDIOT!" moments, and have that be a GOOD thing?

I had been chasing the chatter issue so intently, increasing feed and decreasing speed, that I hadn't been keeping an eye on my cut rate. My inch per tooth had gotten ridiculous.

So, it wasn't actually chatter, it was trying to force a long thin tool to take too much material off per tooth. Why that improved with a dull cutter, I'm not quite sure, but whatever.

But, I'm making parts again. I've got that "clouds of doom are finally parting" feeling.

Thanks everyone!

-Jeff

[Lars]

I always beat blast our new tools, we have WEDM so our beat blaster have very fine grid, it works like a charme.

Lars

[thx1138]

If you got a tumbler, tumble them 1 at a time. how long depends on the media.

[davereagan]

Use G95 instead of G94 and you'll never lose track of your feed per tooth again.

Dave