cutting aluminum

[Grahamd]

Good morning,
Can someone suggest a move speed and depth of cut on aluminum with a .25 end mill?
Thanks, Graham

[MogulTx]

Depends heavily on the alloy you will use.... For a 1/8" bit, depending on the alloy, I run between 1.1/.23 to 1.37/.39.

I never set up for more than .02 depth.

I almost always use an upcut spiral O Flute bit made for aluminum. My fave is Onsrud 63 series bits.

My "cheapie" .25 bit is from Hartlauer. It is the 52-180h.

You can PROBABLY run a little faster with a 1/4" bit, but I tend to keep it slow and steady, so I get a good quality cut.

I ALWAYS SPIRAL RAMP my cuts. I often use either WD 40 or Isopropyl Alcohol dribbled on the cut line as a coolant. (Small quantities of either)

FOr THIN aluminum, I use 16500RPM. For thicker and harder aluminums, I listen to the cutting and look at the chips and adjust until the machine does not sound like it is fighting to make the cut (and make sure the substrate, bit and spindle are all "cool". I do this between cuts, of course)

Best of luck with your project

[coryatjohn]

Another critical thing is really good hold down. Movement can destroy the piece and likely your end mill. Even very slight movements due to vibrations in thin metal for instance, can cause a very poor cut and a lousy surface.

I use the single flute "O" types too, and I've had very good luck with inexpensive pure carbide single flute no-name end mills purchased for $1.25 each on eBay. The smaller end mills seem ok for cheapo. For larger ones, I'd go with name brands. I have a couple of those 1/4" Onsrud 63's myself. They work very nicely.

I go with lower RPM's rather than higher. I like 6,000 for 1/4" single flute O's, and 8000 RPM's for the 1/8" end mills. Using a slower cut reduces the deflection in the machine and for me, makes a nice surface and a closer tolerance.

[Grahamd]

Thank you guys. Good info.
Graham