Milling aluminium alloys

[dennisa49]

Good day,
A little help please?

When I mill aluminium alloys the flutes on the cutters pick up and clog.
End mill and slotting.
Alloys 6061 and 5052.
Difficult to remove the material from the flutes.
6mm up to 12 mm diam cutters, 2 and 4 flutes.
Rocol liquid lubricant, possibly should be kero.

Can someone help me out please? I have tried changing both feed rates
and shaft speed.

Thanks and regards,
Dennis

 

[Cogsy]

I use WD40 as lube when milling aluminium and only have chip clogging/sticking problems when I don't use it. I'm also not big on speeds and feeds, I just run by feel so I'm probably way off optimum.

Edit to add: I bought the 4 litre (maybe 5?) from Bunnings for around $40 and just put a bit in an empty water bottle with a small hole in the lid. Aerosol cans run out way too fast and cost far too much.

 

[DavidLloyd2]

I also use WD40 for milling and drilling aluminium works good,

DavidLloyd

 

[kvom]

2-flute endmills work best as they clear chips best. I wouldn't use the 4-flutes ever. Air blast can clear chips, or use WD40.

 

[Jasonb]

Uncoated cutters are also better at reducing pick up, if you are going to be doing a lot of aluminium machining then there are special cutters for it with a higher helix angle and better clearance.

Kerosene is another option as a cutting fluid.

[ame]https://www.youtube.com/watch?v=AXk2zimLC2c[/ame]

 

[lohring]

Run as high a spindle speed as your mill has. You can machine aluminum at wood cutting speeds. I also use WD 40 as a cutting fluid, though kerosene is a less expensive option.

Lohring Miller

 

[Philipintexas]

Run as high a spindle speed as your mill has. You can machine aluminum at wood cutting speeds. I also use WD 40 as a cutting fluid, though kerosene is a less expensive option.

Lohring Miller

I was going to suggest the opposite.... If the speed is too high I find it "welds" chips to the flutes. I slow the speed and sometimes use cutting oil. Trial & error experience only.

 

[deeferdog]

I initially had a bit of trouble with galling on the milling cutter. I'm a bit the same as Cogsy and don't worry too much about feeds and speeds, I go more on how the machine sounds and past experience. As I understand it, heat build up on the cutter is generally not the problem due to the thermal conductivity of the metal so lubrication is the go. I generally use WD 40 for small jobs and METALIUM XDP1800 from Hare and Forbes for flooding. I have found that concentrating on chip removal pays big dividends in stopping the cutter re-cutting its own chip. Use either low velocity compressed air or manually with a brush. Most of the aluminium I machine is just old saucepan grade and that's always a bit gummy. I have had a bit of success with lard mixed with kerosene (thick paste). As a general spray on fix all, ordinary engine oil thinned with kero is pretty good. Be aware that there is a fire risk with this. I have no formal qualifications in machining so my advice, such as it is, should be viewed in that light. Cheers, Peter.

 

[dennisa49]

Thanks for the advice.
I remembered the kero from my apprentice days. As an aircraft engine fitter not a machinist. It is a long stretch that 50+ years.
I will buy a couple of uncoated cutters and try the various remedies.

It is good to see the volume of experience on HMEM, those years are not being lost. All in all a great thing.
Many thanks and regards,
Dennis.

Gold Coast ,mid winter's day, 15 - 25, bright sunshine.

 

[Wizard69]

Thanks for the advice.
I remembered the kero from my apprentice days. As an aircraft engine fitter not a machinist. It is a long stretch that 50+ years.
I will buy a couple of uncoated cutters and try the various remedies.

It is good to see the volume of experience on HMEM, those years are not being lost. All in all a great thing.
Many thanks and regards,
Dennis.

Gold Coast ,mid winter's day, 15 - 25, bright sunshine.

Kero is often listed as the suggested lubricant for Aluminum machining. WD40 is something like 50% Kero, and combined with the pretreating oils and surfactants in WD40 it performs very well when machining aluminum. Almost magic really.

The trick here is to make sure you get plenty of lube into the cutting action. If using WD40 you obviously don't want to waste it but you can't really let the tool or cutting area go dry either.

As for other lube/coolant solutions I don't have any to suggest. I know you can buy water based formulas specced for use on aluminum but I have no experience with those.

 

[mcostello]

I use any penetrating oil or light oil aerosol spray that I can find cheaply at yard sales. $1 a can is the right price.

 

[lohring]

In the 1970s I watched a 4" carbide face mill absorb 50 hp in an aircraft spar mill. Aluminum flew like wood chips. I personally have used a wood router to machine aluminum plate with a carbide bit before I had a milling machine. You can run 400 surface feet per minute with high speed steel and 1200 surface feet per minute with carbide. On a 1" diameter end mill that's around 1500 rpm with HSS and 4600 rpm with carbide. A 1/4" end mill could run 4 times that. The feed rate should be a few thousandths per blade. The depth of cut should be less than half the end mill diameter. All the above is assuming you want to remove as much stock as possible and have a rigid and powerful enough machine to do it. If not, back off the feed and depth of cut. You can run even higher speeds with light cuts for finishing.

Lohring Miller

 

[john_reese]

I know a lot of people use WD40 or kero when cutting aluminum. I don't like the stink. I have a squirt bottle of soluble oil I use when cutting aluminum. I have a couple mist dispensers but for onesy twosy parts it is hardly worth setting up the mist.

 

[lohring]

I should add that your work piece and method of holding needs to be solid as well. Many of the small parts for our engines are very delicate and need very gentle stock removal. I learned this again the other day while machining the inside of a 36 mm diameter piston with 1 mm wall thickness.

Lohring Miller