Machining Aluminum

[woodworx]

Last week was the first time I had milled aluminum with the machine. The first day was a mild success. Took 11 hours to run the file and melted one bit in the process. I used a combination of the dust collector, air on the bit, lube, and a vacuum to suck out the bits that were piling in deep pockets. I used a feed rate of somewhere around 50 ipm at a cut depth of .08 with a step over of 50% on a 1/4" carbide two flute upspiral.
The machine held up alright, but during the cut, some directions had more vibrations than others. I even had to help it along with a push to keep the vibes down.
I restarted the file with a feed a smaller depth cut. Brady suggested .0625 and it seemed to do much better with the same feed rate.
The next day I cut a second plaque with a cut depth of .03 and busted the feed rate out to 150 ipm. 100% better!
Our machines are not stable enough to with stand deep cut passes, but they are quick. I cut the machining time by 5 hours and wasn't so worried about the machine.
The first day I was a ball of nerves, and the second day I was proud as a peacock to figure out what needed to be done. Here is a pic
6954

[donclifton]

One of the things you have to remember is you want to cut chips not dust. The use of a single flute bit is correct but slow down your spindle. I cut a lot of 1/4 aluminum and I do it in 2 to 3 passes. The faster you go helps to cool the bit. this company supplies bits to most of the sign company that use routers for cutting aluminum and is very help full. http://www.hartlauer-bits.com/HartlauerBitsList.pdf

[mitch_prest]

I am still having a bit of trouble with 1/4 aluminum.. I am trying to do a profile cut using a 1/4" bit. It works fine will I get about 3/16 deep.. then we get meltdown.. lost one bit today, so I figure I would look for help before I offer up the next one. If I want to cut a profile would it be better to try and cut a path wider than the bit...say 3/16 or even 3/8.. would that keep the works cool enough.. I have tried faster with small stepdowns but the aluminum still get pretty hot..

mitch

[paco]

Avoid 3003/utility/common aluminum. You're better with T6 or T7. Harder the better.

Use an allowance (say 0.01") on your toolpath until your deep enough for a final finishing pass. This will leave you with a nice cut edge. You may want to slow the feed a bit for this final pass...