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Anyone have any experience cutting aluminum on a CNC? Do I need to mist it and what type of bit do I need?
Thanks in advance for the help,AndyAndy,
It’s been a while since I’ve cut it, but when I did I used a coolant ( I’ve got one on the cnc). How thick is the material you are cutting? You can get by with a 2 flute O-flute from Onsrud just cut in multi-pass at no more then 1/16″ and keep air on it to keep it cool. Lubricant would be better. Also wear double ear protection because it is LOUD!I was thinking about doing coolant but worried about ruining my spoilboard. Maybe I will use another piece of spoilboard and screw to one on cnc.
What type of coolant do you use and can I spray it with a spray bottle.
The thickness is 1/4″. The parts won’t be that complicate or very large. My kid is making a robot at school and I am helping with the parts cutting.
Vegetable NDF Lubricant from Trico or a like product from Mcmaster Carr. You should be able to spray it. You will mess up the spoilboard, unless you build a jig to hold the piece on top of a piece of laminated plywood. You will have to make sure it is held securely or it will turn into a missile. Try without the lubricant but keep air on it and step cut 1/32 to 1/16 at a time. One more thing watch out for aluminum splinters they hurt like hell coming out
The size (diameter) of your bit will determine the spindle speed. The Onsrud bit previously mentioned will do a good job. You should use a coolant/lubricant.
Using a 1/4″ diameter bit, keep the spindle speed at a max of 4000 rpm if your machine is set up for it. Slower with a larger diameter. Cut depth at each pass at .06 to .08 and feed at no more than 15 ipm. Kerosene will be good enough as a cool/lub for what you are going to do. You can use an acid brush to apply the lub to the cutter. That keeps your machine as clean as possible. A piece of corrigated box surrounding the part will help keep the spoil board clean.
Posted By Fab Man on 31 Jan 2013 07:12 AM
A piece of corrigated box surrounding the part will help keep the spoil board clean.
Nice tip! Thanks
Your welcome.
I had 24 years in the welding/machining and fabrication industry
prior to my 25 years as a solid surface CFI.All self employed.
When cutting aluminum I use WD-40 or another light weight oil, only as much as need to aid in cutting and stiff brush to get any swarf out of the way of the cutter. Most of my cutting of Ali’ is with some what small end mills (6 – 8 mm) and I am normally running about 650 to 700 mm/min. Sorry for that being in metric and if some one would be kind enough to put that in Imperial I would appreciate it. I tend to go conservative on the depth of cut and stick to half or less of diameter of the bit.
Michael
MSC will have small end mills just for aluminum. 3 flutes work real good, less resonance. Buy some cheap brake line tubing or 1/4 copper tubing(easier on cutters if you slip) Mount the air jet to the head so it is close and blows directly on the cutter. Heat will be your enemy with aluminum and it is easy to get buildup on the cutter. When it clogs it snaps. If you know how to make a whistle knotch venturi you can add an occaisonal shot of WD 40 into the air stream. Or mineral spirits. Both are flamable so be at the ready. At least mineral spirits will eventually evaporate.
I cut with flood coolant, about 13 gal/min. The mounting block on the compact V has some major aluminum removal. I cork screw mill the 4.5+- dia hole with a 2″ dia Shear Hog insert cutter. I run them 2 parts at a time in a 9 min cycle. Also in the 9 min cycle is 6 drill holes 2.5 deed and two tapped holes. I have to keep 4 very large trash containers in line to take the chips coming out of the chip conveyor.
So keep it cool.
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