Milling aluminum and cooling

[black5f]

Irving is right, basically relatively light cuts repeated, 0.8 sounds about right, you could rough it first by plunge drilling? The cutting speed should be about 100m per min, by that I mean the speed of the tip of the cutter against the job. So feed will vary depending on spindle speed and feed rate. It can be cut very fast but you will need, serious cooling. The problem with ali is that if your feed too slow, the ali work hardens and gets hot, if too fast it gets very hot, you get a sort of micro melting at the tip of the tool, the ali will stick to the cutter, bind it and eventually you will find you're just melting through! With experience you will be able to here what your machine is saying to you. Have a look at the tool, is their ali on it? Less feed or more coolant (parafin or water). if you've got a nice coolant tray then you cant give it enough. If you havent you can do it manually with a brush, WD40 works fine (to cool) but is a lubricant, not cutting fluid, cutting pastes work like trefolex (washing up liquid) and stay in teh groove but will only work if you keep the feeds and speeds down. If the job heats up, takes a lot of cooling. When you see the type of high speed deep roughing of ali on youtube etc, note the very ample application of coolant. Quick bit of mental maths at 100m/min tip speed with a 3mm cutter and Mr Irving is within a nats whatsit. If you can cool it well then you can drive up the feed a bit (t/c 2 flute!) but not too much. Inspect the tool, is the ali melting and depositing on the tool, thats your indicator. Hope this is of help. Tom

[AdieR]

Paraffin is the "preferred" coolant for aluminium.

Feeds / speeds: not sure quite what kind of work you're trying to do, (pockets, profiles, holes, facing, or indeed the size of job) - machine rigidity and workholding set-up will affect the feed and speed you can apply. I've always managed with standard HSS slot drills / end mills (but good sharp ones, preferably new), though I've no doubt Aluminium-specific tooling would be better (I only do ali on an occasional basis, and generally use my own judgments). The surface finish required (is it specific?) will also affect speeds and feeds you can use.

Some more info would be useful.