Poor Carbide Tool Life

[CHAD]

DON'T USE COATED ENDMILLS FOR ALUMINUM. THE COATING ACTUALY ATRACTS THE ALUMINUM CAUSING IT TO GALL UP, THUS CREATING FRICTION, THUS CREATING HEAT, AND SO ON AND SO ON. LOOK AT DATA FLUTE OR DURA MILL THEY ARE THE KINGS AS FAR AS CUTTING ALUMINUM.

[Rekd]

Chad,

I use coated EM's for Alum ALL THE TIME. Your problem is that you're not generating enough heat to have the properties of the coating start working for you..

Those coatings need heat to work, which means you need to feed them harder. Try it, you'll be suprised at the results..

'Rekd

[HuFlungDung]

Chipping a carbide in 6061 aluminum? Sounds like a coolant problem. Unless you are feeding the coolant through the mill, I doubt that the cutter is even wet at 5000rpm, but for sure it is not being consistently cooled, which a problem for carbide.

I'd highly recommend something like a Trico air/oil coolant unit. It uses an incredibly small amount of lube, yet gets the job done. I have machined hundreds of feet of aluminum with one carbide cutter (3/4" 2 flute regular flute, uncoated) and I don't think it will ever wear out . I typically feed at .004 per flute.

Plus, you should use a high helix 2 flute for optimum chip flow. I don't think they had them readily available (in carbide) back when I bought this 3/4" cutter, but I would sure look high and low for high helix carbide, when this one is done.

[hardmill]

Originally posted by HuFlungDung I typically feed at .004 per flute. Plus, you should use a high helix 2 flute for optimum chip flow. I don't think they had them readily available (in carbide) back when I bought this 3/4" cutter, but I would sure look high and low for high helix carbide, when this one is done.

+1
Thank you Mr.Dung

PEACE

[Fish]

Here's my two cents worth. The reason your end mill was breaking was that the material was building up on the edge, and as the cutter moved along the path, it was trying to cut with aluminium welded to it's cutting faces. My guess is that it chattered alot as well.

I would use a two flute standard carbide thirty degree helix 1/2" at up to 1000 sfm, 1/2" depth, and about 0.003" to 0.005" per tooth to rough. Then, if finish is a problem, use a multi-flute with high helix to go down each side, removing as little as you can get away with at full depth. Probably about 0.001" to 0.002" per tooth per rev. Or, if you really want to remove material quickly, use a carbide roughing end mill made for aluminium for your first step.

I've never had a heat problem in aluminium, either 6061 or 7075 as long as I'm removing enough material to send the heat out with the chip. The problem with using a four flute is that in order to achieve the proper chip load with a fully involved cut, you need to remove too much material for the flutes to spit out. It will usually tell you with chatter before it gives out.

Oh, and as far as coatings are concerned, you don't need them for aluminium. In fact, most coatings will tend to make the flute edges less sharp.

Good luck.

Adam