View Full Version : Miling Aluminium

25-06-2011, 11:34 AM
Hi All,
I need some advice. I have a Myford VMC (Knee mill like the chester 626) with a 2Kw 3 phase Inverter controlled motor.

i am trying to mill some 6mm thick aluminium plate. this materil came with a plastic film on one side.

i have tried using a 6mm 2 flute slot mill (Roebuck 020166) to mill a slot and all i achieve it clogging the cutter and the hole sides look like a piece of putty that someone has poked a finger trough i.e. the sides are peeled back as if it has over-heated.

25-06-2011, 11:55 AM
are you using coolant.

As soon as the cutter clogs you will get an extremely bad finish, was it cutting well before it clogged.?

25-06-2011, 12:41 PM
no i dont have a coolant system. but i suppose i can rig up something to drip (fast) onto the job.
i start to clog almost immediatly. i have tried varing the spindle speed but ge the same result.

25-06-2011, 12:44 PM
sheet ally is usually pretty soft, and will gum up quickly. Try a hand spray with suitable coolant.

25-06-2011, 12:48 PM
Cooling is not important for ali, what is important is stopping the chips sticking to the bit as it's a soft and gummy material. Quick and easy would be WD40, get a can of that with a quick squirt as it goes to keep it lubricated, if your pocketing stop frequently to clear chips, you don't want to be re-cutting them.
Other way of doing it is if you have a compressor, keep a jet of air pointed at the bit to blow the chips away. Coated bits are also good for ali.


Robin Hewitt
25-06-2011, 01:33 PM
Sounds like the cutting edge has picked up a layer of gunge and isn't a cutting edge anymore. Prise it off with a screwdriver. As soon as the edge gunges you stop cutting, start cold forming and the finish goes to pot.

Silly question, but if you don't know what's going wrong you could be a noob. Are you trying to do a 6mm slot in one pass with a 6mm tool? :heehee:

25-06-2011, 01:35 PM
i have tried using a 6mm 2 flute slot mill (Roebuck 020166)
I've been 12mm milling alu sheet with 2 and 4 flute end mill(4flute coated from arceurotrade) to my PC coolers project with constant flow of regular diesel on it as coolant. no clogging at all and nice finish. Maybe you should try it

25-06-2011, 01:39 PM
Wats a "noob". i am trying to do the slots in .5 -.8mm passes.

i used the same slot drill to clean/squar the edges and those seemed to work OK, but if i try slot citting/milling the tool fouls um within 1mm. it was till early this morning a brand new tool. this is first usage.

25-06-2011, 01:53 PM
[QUOTE=croy;22556] i am trying to do the slots in .5 -.8mm passes.
I did 3000rpm while slotting 2mm deep/pass (I can try to find cambam file to check feedrate but I think 60mm/min 4mm dia 4flute) with coolant of course. results: http://malamuterun.co.uk/CPU%20water%20cooler/cpu_water_cooler.htm

25-06-2011, 01:59 PM
i'll try this again in the morning. have to go out this afternoon.
Waitroda if i can get a result anywhere close to your i'd be happy. thanks all for advice.

25-06-2011, 02:01 PM
If you don't get any joy i can pop over and have a nose, i'm local to you.

25-06-2011, 02:03 PM
Hi I2I, Thank you i would be very grateful. Would you consider visiting on a Sunday?

25-06-2011, 02:05 PM
Waitroda if i can get a result anywhere close to your i'd be happy. thanks all for advice.
You welcome :)
I would insist coolant is key to your success, but I can be wrong of course :)

25-06-2011, 02:05 PM
Sunday's fine, i'll pm you my contact numbers.

25-06-2011, 05:21 PM
Looks like you're sorted now, but either way you might find a program called 'GWizard' useful. It calculates feedrates and spindle speed for various situations...very useful:


Equally if you google for how to calculate feedrates - it can be as easy or complicated as you want!