Flood coolant is what you want, if you watch a cnc milling aluminium at high speed the coolant blasts the swarf away so as not to interfere with the cutter. Make sure your end mills are very sharp to, or they tend to smear the surface.

Hi Paul,

As Ronan says; sharp cutters and coolant, and yes, there are special milling cutters for aluminium, see here, or here. I havent tried them myself, I just use new slot drills.

Thor

Paul,

You don't have to use flood coolant but as you found out cutting Aluminium dry is also not a good idea, try brushing on Paraffin, soluble oil or cutting oil, all will help to prevent 'sticking'

Tony

I use soluble oil in a squirt bottle. It does not take a lot prevent chips sticking. When slotting the occasional air blast will help remove swarf. I am going to try a mist coolant unit. Haven't got it set up yet.

The grade of aluminium alloy has a huge influence. I've only once had a problem and just accepted it was a poor grade of alloy for machining and discarded it. I do all my milling dry except sometimes for a finishing cut.

Tim, that's my photo and the plate is 6082 T6, HE 30 in old money and I had no problem cutting it.

Edited By JasonB on 06/02/2017 17:53:55

The hollow in this 6082 bar is about 275mm long and 7mm deep, I chewed it out with an ARC uncoated cutter to full depth at each pass. Not the very best finish as I was just hogging out waste to reduce weight.

Screwfix do wd40 for £6 per litre if you buy 5l. More expensive than a neat cutting oil, but not rediculous.

Me too, we had a paraffin heater at home when i was a kid, very distinctive smell.

I mix paraffin and ATF [ automatic transmission fluid] at 75% to 25% ratio and find you get the best of both worlds.but any light grade hydraulic oil will work, it's just that I have gallons of the stuff.

Don't use a 4 flute cutter, there isn't enough space between the flutes to get the chips away given alloy being softer is cut faster.

Routers that cut aluminium often use 1 flute cutters, no it's not April the 1st. These have maximum chip clearance than any cutter.

Problem with flood cooling on small hobby machines with no full guarding is you can't get enough flood. You need to wash the chips out of the cut and once you are say 10m or 12 mm deep that's a fair bit of pressure to make things messy fast.

In my new proposed hobby workshop at the new house [Tm] I plan to fit curtains to the bench mill, whatever model that is. Two / three brackets screwed to the ceiling both sides to support a length of plastic conduit with a slit in it. Into this slit will be some lengths of that black plastic DPC membrane you put on brickwork as a damp course [ because it's cheap ] This can be would up when bot in use and wound down when messy milling and it will catch the chips which will fall into a designated area to be cleaned up instead of all over the shop, in me boots and down me neck as it does at the moment.

Don't know if I can apply for a patent or whether it's someones else's idea I have subconsciously remembered [ my excuse ]

Take your lump of alloy and a 1/4" sharp drill and belt a hole straight thru it using constant pressure all the way.

If when you turn it over it's got a small burr you can remove with a de-burring tool then it's OK.

If it's raised a big burr up like the Yellow Rose of Texas then it's T60softas$hit and needs throwing at next doors cat.

Simples.

I find 5083 actually machines better than 6082 the chips come off shorter, I always use flood on the cnc mill but somtimes use WD40 on the manual mill for finishing which I buy in 5ltr containers and apply with a spray bottle, cos I like the smell………

The better grades of Ali tend to ring if you tap em with a spanner etc.

Shaun