Newbie- Cutting aluminum

[chris123]

I'm after some advice with milling aluminium

Firstly I have a small Taig desktop mill
The parts I make are made from aluminium plates ranging in thickness from 3mm to 12mm
For the 3mm parts I cut 3mm in one pass the thicker parts I mill multiple depth passes, essentially I do a lot of slotting

Should I be using endmills or slotdrills?
Should I get a tool specifically made for aluminium?
For the specific tools can get "Solid carbide K grade slotdrills" or "Solid carbide fire coated endmills"?

I currently use a HSS 2 flute 6mm end mill 6,000rpm at 24ipm for most of the work I do

[Geof]

What you need is a two fluted high helix micrograin carbide end mill. Here in Canada two makes are Garr and Gorilla but there are many others. The high helix which acts to pull the chip up out of the cut, micrograin carbide can be sharpened to a very keen cutting edge and two flutes give good chip clearance.

You don't mention whether you are using coolant or lubricant, certainly you should be. Flooding with collant could be messy but a mister could spray a small amount of coolant on the tool and this will help immensely.

With a 6mm cutter running at 6000 rpm in 6061 aluminum alloy with coolant you should be able to cut at least one diameter deep at the feed you are using.

[chris123]

I'm using flood coolant
I dont know about micrograin carbide but I can get solid carbide
What is considered a high helix angle?

[Geof]

45 degree helix or somewhere around that.

This company is the distributor for GARR tools down there.

SEI Carbide Australia - Tungsten Carbide, CBN, and Diamond cutting tools.

[Delw]

Garr is what I use, the smallest coated endmill for alum cutting they make That I can get ahold of here is 3/8. I am told a 1/4" is suppose to be avail this coming year.

with a 1/4" (close to 6mm)garr standard 2 flute ball non alum cutting normal helix I run 8500rpm at 100-115 ipm with a .035 step over at up to .175 depth of cut. it screams and its loud. but it works and last quite a long time.

Delw

[chris123]

What depth can you cut slots with this tool?
As I cut more slots then profile

[Delw]

as deep as the endmill has cutting flutes, you can get extended ones pretty long

[chris123]

Really... If the tool had 20mm flutes I can cut a 20mm deep slot in one pass with this tool?

[Geof]

Originally Posted by chris123 Really... If the tool had 20mm flutes I can cut a 20mm deep slot in one pass with this tool?

NO!

You can get that deep in multiple passes. In aluminum for instance, I would go down about 1mm per pass at 10,000rpm and a feed of maybe 50mm per minute (although that feed may be a bit high, I am not sure).

There would be considerable deflection so if you were cutting a 6mm wide slot it would be wise to use a tool about 5 or 5.5mm diameter and offset it to get the correct width.

[chris123]

I use HSS at 6,000rpm at 600mm/min and go 3mm deep

[Delw]

Originally Posted by Geof NO! You can get that deep in multiple passes. In aluminum for instance, I would go down about 1mm per pass at 10,000rpm and a feed of maybe 50mm per minute (although that feed may be a bit high, I am not sure). There would be considerable deflection so if you were cutting a 6mm wide slot it would be wise to use a tool about 5 or 5.5mm diameter and offset it to get the correct width.

Originally Posted by chris123 I use HSS at 6,000rpm at 600mm/min and go 3mm deep

NO way not in one pass,
Have you ever done machining before? I assumed you did thats why I gave you the info I gave, sorry if I confused you.

Delw

[chris123]

I've been machining for about 6 months
I also use flood coolant