Need guidance on machining Alcoa mic 6

[Rcnewcomb]

A shop near me has cutoffs of Alcoa mic 6: 5" x 11" x 0.75"

For CNC work, how does it compare to 6061 for machinability, feeds, and speeds?
Can I just spray some WD40, or does it need a machine with real coolant flush?

I was thinking of using an O flute spiral upcut bit since I have a few of those.

Thoughts?
Encouragement?
Warnings?

[PRO4824]

Oh, that stuff is terrible! You should box it up and send it to me for proper disposal!!

Seriously, I think it's about the same as 6061 maybe better.

[sharkcutup]

Maybe TReischl will chime in!

Sharkcutup

[martin54]

Not one I have come across so did a google search, came across this

https://keymetals.com/aluminum_guide.html

I generally use an airline with a gentle blow aimed at the cutting bit to remove the chips as my dust extraction isn't the best

[TReischl]

Maybe TReischl will chime in!

Sharkcutup

You are going to need a new ! key soon.

[TReischl]

Randall, the stuff cuts beautifully. Had a chunk laying around here for quite a while and finally used it up a couple of months ago. I was totally impressed. I tend to use WD-40 when cutting aluminum to keep chips from welding to the cutter. Not so much on the regular mill though, course the spindle on that is not turning at revs measured in the tens of thousands.

[Dan O]

Mic 6 is CAST Aluminum, as opposed to billet or wrought. Also known as cast tooling and jig plate. It will machine fine without much welding to the tools. WD40 will work fine. Kerosene works really well too, but NOT RECOMMENDED in a wood shop. We use it in the machine shop for finish milling where there is no danger of fire. It will have more porosity than 6061. The finish won't be as "shiny", more dull than any billet. It doesn't polish very well.

[Rcnewcomb]

It will have more porosity than 6061. The finish won't be as "shiny", more dull than any billet. It doesn't polish very well.

That will help me manage my expectations.

I'm going to pick up one piece tomorrow to see how it machines. The shop has 160 pieces of good sized cutoffs of consistent size and shape if I'm interested in more.

[sharkcutup]

You are going to need a new ! key soon.

Suppose I get you to CUT me one out of Aluminum --- It might last longer!!!!!!!!!!!!!!!!!!!!!!!!!!

Sharkcutup

[Rcnewcomb]

The Onsrud Super O bit I have shows a chip load of 0.003 to 0.005 for aluminum.

What RPM should I run the spindle at?

[TReischl]

Depends on your spindle rpm.

At 25K you will need a feed rate between between 75 - 150 ipm (that is based on .003 - .006 chipload).

But like we all talk about it is also dependent on how rigid the machine is. I am not familiar with your machine.

I sure as heck cannot run that fast on my machine without chattering in aluminum. I slow my spindle down to 16K and the feedrate to about 50 IPM. Depends on the size of the cutter too. My calcs above were with a .25 dia end mill.

Hmmm, just noticed that cast aluminum has about half the SFM of the extruded stuff. Sooo, you will want to adjust accordingly. Come to think of it, that is probably why I was happy as a clam cutting that stuff I had a while back.

[Rcnewcomb]

dependent on how rigid the machine is

It is a pretty rigid machine with a 2.2KW (~3HP) spindle.

For context, I usually run in the 12K-16K RPM range for wood, corian, and limestone.

[TReischl]

That is a huge help IMHO.

There are quite a few on line calculators for feed and speeds so that should get you started.

When I run the stuff on my machine I never get real chips like I do on the small mill. One thing I do know, HSS works well on aluminum. Tends to give a better finish. Sooo, maybe a two flute end mill with a faster feedrate (since you have a pretty rigid machine) ???

I have learned my lesson with aluminum welding to the cutter. I either keep it wet with WD or I put some air on it to keep the chips clear. BTW, if you do weld it to the cutter it can be pried off, it is not really welded.