Correct Chips for milling?

[Cire]

I am wondering if there is a "best" type of chip when milling. My endmill/mill has been making more of dust then the chips I am used to when I learned how to machine. I am mainly cutting aluminum. Is this normal for milling with small mills (x3) or am i doing something wrong?

A few things that I think might be the reason why, but I am not sure:

- Feed rate too slow and not cutting off enough material at a time.
- Cheap end mills (Harbour Frieghts).
- Not enough cutting fluid.

Please help me

[yoopertool]

There is no one perfect universal chip. Lots of things affect chip characteristics, like material, cutting tool, cooling method, depth of cut, conventional vs climb cutting.....and the list goes on. I would suggest finding the specified chip load for your tool and doing some calculations to figure out what you should be feeding at with whatever RPM you are using. If you post some specifics about how you are cutting, , depth of cut, what rpm you are using, and the style of endmill you are using, I am sure someone will give you some good suggestions on how to get more suitable chips.

[SKEETO]

Your first two thoughts are on the money. On aluminum i set SFM @ 650 and a chip load of .01.

[RICHARD ZASTROW]

Personally I like chips that "clang" when they hit the floor rather than "tinkle".

[dertsap]

the chip should have a nice curl to it,
if your creating dust your feed rate is too low

[eorourke]

The rule of thumb in carbide tooling( insert) is a minimum chip thickness of .004" (average). In milling this can be calculated using radial engagement of the cutter and the feedrate of the machine and the diameter of the tool. ie. if your depth of cut is .050" on the side and your cutter diameter is 1" with 4 flutes and your rpm is 3820( 1000sfm) then your feed rate per tooth should be .009" or 140 IPM. If your radial engagement is .100" then your chip load should be .0066".
If you are making dust then your feed rate is way too low and you are babying the cutter. Sure you will get a very nice finish but you are in effect rubbing the material away. You would be better off grinding. Both HSS and carbide want to work and the feed rate is where you get them working.

[Guldberg]

I have a nice program for calculating speed and feedrate if you send me a PM with your email

[sluggo]

One rule of thumb when face milling, is that they should be shaped liked 6's and 9's.

[eorourke]

It depends on the cutter and the depth of cut- ie. a 45 degree face mill with 20 degree axial rake and -4 degree radial rake will produce pig tails for chips. They are just as effective but this is due to the geometry of the cutter and the radial and axial engagement.

[RICHARD ZASTROW]

I can't resist. 6's are right hand and 9's are left hand. lol

[ironDigit]

a while ago someone posted a link to a video of a high speed vmc that was not only creating dust but actually sparking like a grinder instead of making nice chips.

i guess as long as your within your cuttingtools limits and your workpiece comes out nice . ....



sry man 1pence is all i got on me

[ConKbot of Doom]

Originally Posted by ironDigit a while ago someone posted a link to a video of a high speed vmc that was not only creating dust but actually sparking like a grinder instead of making nice chips. i guess as long as your within your cuttingtools limits and your workpiece comes out nice . .... sry man 1pence is all i got on me

That all depends on your work matl. It your working on stainless or something similar with ceramic inserts, sparks are to be expected. If you have aluminum sparking on the other hand...