Feeds and speeds drilling aluminum

Hi guys,

What feeds and speeds do you use drilling aluminum on a cnc router? I'm making a tooling/fixture plate and need to drill about a hundred 5mm, 13mm through holes. The problem obviously being the minimum rpm of my spindle being 12000.

Did some initial holes yesterday with a 200mm/min feed and 12000rpm, 4mm deep spot then 5mm HSS (brand new Bosch) twist drill, peck depth 1.5mm. Lubricated with cutting oil. No coolant. It cut the 12mm holes deep holes no problem, but OMG it whined like it was being tortured with a dull pocket knife.

I do think I need to increase my feed? Mr. Bonzo came to visit before the first test cut and I set the wrong Z offset and the drill plunged in about 1000mm/min with no peck and although it was way to brutal, it seemed to cut fine with no apparent squeaking and whining.

What feeds and speeds do you guys use when drilling aluminum on a router with a high speed spindle?

(I've consulted GWizard, but it doesn't seem to have a good suggestion and errors out on the min.rpm).

Have a good one.

H.

Hiya Henrikm,

I have a good milling speeds and feeds app on my phone which I use everyday at work!

I can only set a max RPM on the app, so I have put 14000 and it says you want to be running it at 7571rpm and 1135.72mm/min (this is with a 5mm hss drill) and for the 13mm drill 2912rpm and 913.82mm/min.

So I guess turn your feed up! What power Is the spindle motor?

Regards,

Jack

Thanks Jack. The spindle is 2.2kW. I've done some more trials and with good quality Gühring stub drills, peck cycle and coolant/lube it works out OK, but it's still squeaking quite a bit.
Will continue to experiment.

I checked with FSWizard Pro on my phone, and since I don't know what kind of aluminium you have, I just put in 6061-T6 and it gave me a speed of 1800mm/min with a 5mm HSS jobber twist drill (which I believe is the normal type drill bit) for 12000RPM.

You are not going to get very good results with a drill bit in a router. It never gets a chance to cut. It is just dancing on top of the material and that is why you hear it. Drills need relative low spindle speed. The larger they are, the lower the speed needed.
Your best bet will be to use a center cutting router bit or end mill. Machine the holes rather than drill them.

If you do use a drill at that speed, Then I would suggest shallow fast pecks. it will make a tiny chip and then break it. That will reduce the heat on the bit as well. Heat kills tools. Speed creates heat.

You might consider getting solid carbide drill bits. I cut holes all the time with these running at a spindle speed of 8000 RPM without coolant and also use peck drilling with .1" pecks. They drill perfect. I use a water cooled spindle which has the low speed of 6000 RPMs. If I try this with regular steel drills they sound terrible but with the solid carbide drills they work great.

I suggest you can use drill bit rigs/router. Drill machine milling speed is according to power voltage loads. In 5mm to 13 mm drill hole can easily adjust with 8000rpm drill machine.