High helix end mills keep gouging

[kdoney]

Originally I was running at about 2000 RPM but I slowed it down on advice. The mill head is mounted on an extremely heavey and rigid gantry mill so I can take the head as far as anyone. This is a chinese mini mill with the R8 taper. Max speed is 2500 and the 4/5 horsepower claim is a lie. I can't believe I can get to, yet alone, go beyond a .010 cut! I can hear each tooth of the 1/4" 2 flute high helix carbide ticn coated mill slamming into the metal now at .004. If it helps I can change to another head. I have a 10k rpm sherline I could mount if the jobs would get done faster but the torque kept stopping the stock motor on that one.

[JPMach]

All be it I am running a haas vf-4 but in aluminum I run a 1/2 60 deg helix two flute carbide endmill at 5500 rpm and 20ipm at uo to 7/8" depth of cut and full cutter width stepover. Spinle load is only slightly above 50% and the chips just fly out there. You do have to be carful on finish passes though to ensure no recutting of chips, lots of coolant or air helps.

JP

[kdoney]

Thanks. That certainly helps

[carlnpa]

What type of cutting fluid are you using?

[little bubba]

Originally Posted by kdoney Does roughing end mills speed up the process much? What other tooling have you mini mill guys used to speed up "hogging" large amounts of aluminum?

Not a mini mill guy, but a lot can still be learned. My general rule concerning roughers and finishers is that a rougher can take out at least 3 times more material than a finisher in a given time. Tool pressure drops immensly, your spindle load will go way down. Take a rougher and a finisher on a manual mill and you can really feel the difference when cranking the handle.

My experience with high helix endmills is that they leave a great finish, but really suck at removing large amounts of material. Since your on a mini mill and your rigidity is limited, I would go with a rougher. On a more rigid machine a finisher can really get at it on aluminum, but a rougher will still outdo it.

My rougher aluminum story, one saturday we were screwing around and just seeing what our Mazak could do in aluminum, since we don't get to play with it much. 4 flute carbide rougher at 12000 rpms, at max feed of 708ipm. .375 DOC .25 step over. about .0145 chipload per tooth. I wanted to see what kind of chipload it could take and since at max feed already started backing down the RPMs. I got to a .029 chip load per tooth, thats when I got scared and gave up. The chips were getting bigger than some of the parts we make. We did roast one endmill when we tried cutting on the backside of the "test piece" where the coolant couldn't get in.