Miling Aluminium

[croy]

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.

[i2i]

are you using coolant.

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

[croy]

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.

[i2i]

sheet ally is usually pretty soft, and will gum up quickly. Try a hand spray with suitable coolant.

[Rikk]

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.

..........Rikk

[Robin Hewitt]

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:

[croy]

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.

[wiatroda]

[QUOTE=croy;22556] i am trying to do the slots in .5 -.8mm passes.
/QUOTE]
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...ter_cooler.htm

[croy]

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.

[wiatroda]

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 :)