Poor Carbide Tool Life

[CoolHand]

I'm using a 1/2" 4 flt solid micrograin carbide square end mill to cut 0.75" deep slots in 6061 T-6 aluminum.

I'm spinning the tool at 5000 rpm, feeding it at 40 IPM at a DOC of 0.1"

That gives me .002 IPT, which I thought would be easy enough for the carbide to handle.

Wrong.

I have cut maybe 1800 linear inches with this tool, and already it is destroyed.

Not broken, but the ends are chipped, the flutes are chipped, and it is now leaving swirl marks all over. Basically, its done.

Whats wrong? I am using a water soluble lard oil cooland/lube, mostly to flush the chips out of the slots.

I've got to fix this somehow, as ruining a $40 endmill every time I cut this part is really cramping my profits.

I know something is wrong, but durned if I can figure out what.

Could it be poor quality tooling? I've been contemplating switching to indexable endmills, but I want to be sure that this won't happen with them too.

Any help would be most appreciated

Thanks for your time.

[Rekd]

Try coated EMs, Tailn or Ticn. Also, bump up the chip load, double it or more. You're pre-maturely wearing down the cutter by 'rubbing' too much on the material. (Make each pass of the flute count, take as much as you can.. removes heat as well )

Carbide will work nicely, but inserts will work better, IMNSHO.

Hardmill will prolly have a say on this as well...

'Rekd

[hardmill]

Originally posted by Rekd Hardmill will prolly have a say on this as well... 'Rekd

Up the SFM if you can and +1 rekd on the chip load.
But most important is ditch that 4 flute endmll (yuk!!)
Not nearly enough relief.

PEACE

[CoolHand]

I'm thinking of switching to a 1 flt .5" indexable, or a 2 flt .625" indexable.

I have to have a good surface finish when the part is done. Will the 1 flute still give me a decent finish?

5000 rpm is the top spindle speed on my machine, so SFM is as high as its gonna go. I can bump up the feed all the way to 280 IPM (max cutting feed) if needs be to get the FPT up where it should be.

BTW, what FPt would you guys suggest for the 4 flt? I've got one more setting here, so I might as well use it.

The indexables I was looking at suggest FPT in the neighborhood of .010" Would this be a good place to start for coated inserts with the right geometry?

Your previous suggestions are very helpful, any others would be equally well appreciated.

Thanks again for your time.

[Rekd]

The problem with single flutes are the feed it needs to go to achieve the same chip load. (For finishing, this means much slower feeds to achieve a good finish as opposed to, say 4 or 6 flutes.) It might be worthwhile to rough and finish with 2 different tools, so you can finish faster.

'Rekd teh hardmill? We're tied again..

[hardmill]

Either pass me or slow down, but get off my a%#

I really don't like that 4 flute, not nearly enough relief.
+1 on the fpt for the insert mills though, just make sure
they get you the proper inserts.( for alum)
Sorry to hear about the max spindle speed

PEACE

[CoolHand]

That idea had occured to me too.

I was thinking of using the 2flt 5/8" indexable to rough with, and a 1/2" 6 flt OSG rocket mill to finish with.

I'm also looking for a good indexable corner rounding endmill. Something with a 3/16" radius, and it would be nice if it were center cutting as well. Anybody know ofhand where I might find something like that? (Preferably for under $150)

BTW, Rekd, you are johnny on the spot with the replies tonight. Good job. Its almost as good as instant messages.

Thanks again.

[Rekd]

I use 4 flutes almost exclusively for finishing microwave housings, (brass and alum) and other critical surfaces where I want to move quickly.

'Rekd teh 'Beep Beep'

[Rekd]

Originally posted by CoolHand That idea had occured to me too. I was thinking of using the 2flt 5/8" indexable to rough with, and a 1/2" 6 flt OSG rocket mill to finish with. I'm also looking for a good indexable corner rounding endmill. Something with a 3/16" radius, and it would be nice if it were center cutting as well. Anybody know ofhand where I might find something like that? (Preferably for under $150) BTW, Rekd, you are johnny on the spot with the replies tonight. Good job. Its almost as good as instant messages. Thanks again.

The rocket mill sounds good.

The center cutting CRE will prolly have to be custom made. I don't think I've seen them before.

I'm sitting here sipping a Rum & Coke, beating Hardmill to the new posts..

'Rekd teh nuttin but love..

[Rekd]

I think he's on a dial-up, or types slow tonite..

[hardmill]

Originally posted by Rekd I think he's on a dial-up, or types slow tonite..

Hey pal I always tetete ype slow

PEACE

[CoolHand]

Originally posted by Rekd The center cutting CRE will prolly have to be custom made. I don't think I've seen them before.

I was afeared of that.

Oh well, I'm off to bed.

Thanks for your help guys.