Deep Drilling Aluminum

[Rex Smith]

I need to drill some 1/4" x 1 1/2" holes in aluminum using a carbide 2 flute drill bit. I'm running 5000 rpm at 19ipm and pecking .4". Spraying WD40 from a can. The bit is getting hot and galling, so I assume I'm running things a little too fast. Can someone tell me the recommended speeds and feeds for these holes?

thanks, rex

[sandrewb]

try 3500rpm and a .005"/rev feed

[joeavaerage]

Hi,

1/4 inch= 6.35mm or 0.00635m
Surface speed= 0.00635 x PI x 5000 (rpm)
= 98.7m/min

So the surface speed should be good for aluminum.

I suspect your real problem is chip evacuation, or rather the lack of it. If the drill recuts the chips that's when you get major heat build-up and then the chips weld
themselves to the drill.

Can you use flood cooling? Flood cooling is valuable because it tends to flush chips out of the cutzone, the cooling and lubricating effect aside.

You may have to use much shorter pecks with chip clearance between pecks.

Craig

[RCaffin]

real problem is chip evacuation, or rather the lack of it.
Agree
I usually peck drill no more than 2 mm, and with a good air blast for clearing. G83 z** Q2 R2
Soft aluminium can be more difficult than steel.

Cheers
Roger