Issues Milling Aluminium

[Twizseven]

Hi there,

I've been member of this site for 3 or 4 months and just look with amazement at some of the work being done by members. I am based near Lichfield in the UK. I have workshop with several lathes (Colchester Student and Myford 7) and and milling machine (Chester Super Lux) but cannot find the time to use them as I would like. I have been trying today to mill a 1/4" wide slot 2.5" long in a 1/4inch thick aluminium sheet. I am using a 1/4" dia. 4 flute slot cutter. It pierces down through the aluminium OK and cuts the first 1/2" of the slot and then the ali just builds up on the cutter and it ceases to cut. I am not geared up to use cutting fluid. I have had problems every time I have tried to mill aluminium. What am I doing wrong.


Thanks in advance,

Colin

 

[Tin Falcon]

use pubished speed and feed
a two flute mill cutter will give more chip clearance.
a bit of w-d 40 or paraffin (kerosene in the USA)will keep the chips from sticking.
What depth of cut are you using you may be cutting too deep at ones as well.

Tin

 

[Swifty]

Hi Colin,
Welcome to the site. You could try using some WD40, CRC etc whilst cutting. I always have a can available when cutting aluminium. Depending on the grade of aluminium, some cuts really well whilst some cuts like putty.

Paul.

 

[stevehuckss396]

Hi there,

I have had problems every time I have tried to mill aluminium. What am I doing wrong.

Lube!

It's that simple. The aluminum gums up and welds to the cutter and it will stop cutting. You don't need to flood the cutter, just a squirt here and there of what ever you perfer. I use WD40 myself but know others who use kerosene, transmission fluid, cooltool, you name it. Just lube with something and you should have better results.

 

[goldstar31]

One of the best lubricants for aluminium is lard oil. I would try lard, bacon grease or cooking oil as alternatives. I use lard oil almost exclusively having a Myford as well. I drill and tap with it too.

Cheers

Norman

 

[Twizseven]

Thanks Tin for quick response.

Not sure I have a two flute cutter but will have a look. I tried 25 thou depth of cut and also full depth of cut. I started off with a 6mm hole drilled all way thru. Now I think of it I have used paraffin when drilling ali on lathe but never gave it a thought with the milling..

Colin

 

[Twizseven]

Okay, So it looks as though lubrication is the key. I'd better find out the old Fairy Liquid plastic squeeezy bottle. I think this ali is very soft. Now I have gummed up milling cutters whats the best way to remove the ali from the flutes.

Colin

PS thnaks for the other very quick responses.

 

[stevehuckss396]

Okay, So it looks as though lubrication is the key. I'd better find out the old Fairy Liquid plastic squeeezy bottle. I think this ali is very soft. Now I have gummed up milling cutters whats the best way to remove the ali from the flutes.

Colin

PS thnaks for the other very quick responses.

Lube and start milling and i would be willing to bet the cutter will clear itself.

 

[Omnimill]

Once you're clear on speed and feed WD40 or paraffin works fine for Aluminium Alloy, also stop and clear the chips once in a while. Bottom line though is the type of alloy. I tried to mill some unknown stuff a while back and it was just too gummy to machine well.

 

[canadianhorsepower]

Okay, So it looks as though lubrication is the key. I'd better find out the old Fairy Liquid plastic squeeezy bottle. I think this ali is very soft. Now I have gummed up milling cutters whats the best way to remove the ali from the flutes.

Colin

PS thnaks for the other very quick responses.

If it doesnt remove itself (aluminium from the mill)
let your end mill sit in sulfuric acid (drain cleaner) and the aluminium
will vanish........
use a well ventilated area and cover your hand properly.
if you have any silver where bring them at your neibour's house when doing thisRof}

 

[Lakc]

Do not use any fancy titanium coated tools to cut aluminum either. Ti= aluminum glue.

 

[terrywerm]

Do not use any fancy titanium coated tools to cut aluminum either. Ti= aluminum glue.

I forgot about that once and used a TiN coated end mill on some ali - but not for long!! :wall: Luckily it did not stick so bad or so long that it ruined the part, and I was able to switch over to a regular HSS end mill and finish the job.

I guess I won't make that mistake again! ;D

 

[canadianhorsepower]

I forgot about that once and used a TiN coated end mill on some ali - but not for long!! :wall: Luckily it did not stick so bad or so long that it ruined the part, and I was able to switch over to a regular HSS end mill and finish the job.

I guess I won't make that mistake again! ;D

the reason for this is simple
you have to reduce your speed by 30% for this not to happen
even in steel

 

[Tin Falcon]

lard oil IS recommended for milling
so is mineral oil and soluble oil even some lard oil mixed with kero probably OK. NOT Bacon grease yuk to much corrosive chemicals nitrates salts etc no way Jose'
Tin

 

[Omnimill]

NOT Bacon grease yuk to much corrosive chemicals nitrates salts etc no way Jose'
Tin

Now that's a shame Tin as it would smell soo nice while you were working!

 

[Twizseven]

I'm sure I have bottle of sulphuric acid around from battery top ups so will try that to clean up cutter

Thanks for all the advice.
Colin

 

[abby]

You clean your drains with sulphuric acid ?

 

[canadianhorsepower]

I'm sure I have bottle of sulphuric acid around from battery top ups so will try that to clean up cutter

Thanks for all the advice.
Colin

sorry :wall::wall:not sulphutic acid

but muriatic acid ( cement cleaner)

 

[LongRat]

When my cutters clog I knock the clogging out with a short length of 1.6mm piano wire and a hammer. Not chipped a tool yet.
Also, if you can get GT85 (Halfords) use some of that, it is even better than WD40 as a lube for aluminium. However I think switching to 2-flute will make the biggest difference, its possible to clog a 4-flute endmill that small in aluminium even with flood coolant in some of the softer grades.

 

[Twizseven]

Luc: I must admit I wondered what there was in drains that needed sulphuric acid. I will get cement cleaner and put the suphuric away.

LongRat: I assume GT85 is Halfords equiv of WD40.