Chip Welding

[ctwo]

0.08" 2-flute HSS cutter (RIP)
3k RPM
single passes 20 thou deep
6ipm
cutting dry

I'm having this melted aluminum stuck in the groove. These seem like such light cuts, so what can I improve? I want to use a smaller cutter too.

[GlennW]

Flood coolant

[ctwo]

I could consider something like cool mist. Maybe just air? I was wondering if the mill might have been dull. Are more aggressive means really necessary for such light work? I do remember someone mentioning to use 4-flute mill for strength.

I never had so much trouble with aluminum on my manual mill, just on this CNC. Of course I am doing different kinds of things...

[Harold_V]

0.08" 2-flute HSS cutter (RIP)
3k RPM
single passes 20 thou deep
6ipm
cutting dry

I'm having this melted aluminum stuck in the groove. These seem like such light cuts, so what can I improve? I want to use a smaller cutter too.

Blink! Blink!
Can you help me understand why that mess looks black?
3 k rpm isn't all that fast for such a small cutter, especially in aluminum. If you have the ability, crank it up to around 10,000.
Are you running the spindle backwards? No, I'm not trying to be rude. Unless the cutter has issues (including chip welding), I can't imagine why it would build up as it has.

I'm of the opinion you are suffering from low speed and chip welding. Cutting dry isn't a good idea with aluminum, especially if it's not 2024 or 7075, each in a hardened condition. Even 6061-T6 likes to chip weld, especially when being machined dry. Consider keeping the cut wet with kerosene, or even WD-40. It can be brush applied with excellent results.

Edit: Lose the idea of using four flutes in aluminum.

Harold

[GlennW]

I was wondering if the mill might have been dull.

Buy a new end mill so you know it's sharp, and use some sort of fluid.

If you are trying to use used end mills that isn't the way to go.

A can of WD-40 would probably be the easiest to try.

[ctwo]

The black is just a result of the camera on highly reflective material.

Chip load was only 0.001" and the first few passes worked great, so it must have been fine chips building up in the pocket. All my end mills are used, so that could have contributed too.

I'd like to cut out 1/4" high letters all the way through 1/16" aluminum in one pass with a small cutter (0.04"). That's probably not going to happen on my Bridgeport. I can crank it up to 4200 RPM though.

[SteveM]

I use tap magic for cutting fluid, apply with a brush and that pretty much gets rid of my aluminum chip welding issues.

Steve

[seal killer]

ctwo--

I cut aluminum as fast as my mill will turn. With a 3/4" end mill, that is about 600 SFM. I use a LOT of WD40. No chip welding. Although I used to be a victim of chip welding before I cranked that baby up.

Two flute, for sure.

--Bill

[Magicniner]

Using an occasional squirt of WD40 or paraffin for cutting lube and air to clear chips & cool the job will reduce your problems, I run 2mm 2 flute in Aluminium at 6k to 7k but I prefer single flute at double the speed,

- Nick

[Harold_V]

I'd like to cut out 1/4" high letters all the way through 1/16" aluminum in one pass with a small cutter (0.04"). That's probably not going to happen on my Bridgeport. I can crank it up to 4200 RPM though.

Not "probably". It isn't going to happen, not under any circumstance. Expecting an end mill to take a full cut, depth of which is beyond it's diameter, isn't reasonable.

Harold

[Magicniner]

Speed & Feed calculations required, that will provide a reality check.
A spindle speeder or a secondary high speed spindle is extremely useful for this kind of work,

- Nick

[ctwo]

I went to a 0.05" carbide cutter that is sharp and it went much better. I think the reality is that my machine is going to take 0.001" steps and does not have a 10k spindle. I have thought of making a knuckle for the other side of the ram and installing one of those Chinese integrated 10k+ spindles.

Harold, maybe I've watched too much youtube... https://youtu.be/L5R2s9uRgOY?t=19