[Spk64]

It is a carbide end mill.
Here is the part number but I think I got it on eBay.
1/4" Square End Mill Standard Length HTC 120-2250 2FL GP 30

What problems are you having?


Steve

[bobmagnuson]

A lot of chattering, broken bits, etc. I believe a combination of an aggressive DOC and speed.

[Spk64]

Could be a bad collet or bad spindle.
Are you using a router or spindle?


Steve

[bobmagnuson]

I was using a Bosch router (non variable speed). The last cuts where to create the mounting plates for my spindle which I haven't tried on aluminum yet.

In other words... Cutting too deep, moving too fast and spinning way too fast!

[Spk64]

With a router need really shallow cuts. I ran a router on my machine for awhile and cutting aluminum was tough. The bearings are not all that great in most routers.



Steve

[bobmagnuson]

Agree! I'm using a 4.4hp spindle now and I'm sure it would be much better! Double bearings at the nose helps quite a bit.

[ger21]

Try a single flute "O" flute bit. I've gotten good results with an Onsrud "O" flute, even with a worn out PC690 and my flexible machine. Be sure to climb cut.

[bobmagnuson]

Steve, I feel like I'm high jacking your thread...Gerry, are you using coolant?

[louieatienza]

I was using a Bosch router (non variable speed). The last cuts where to create the mounting plates for my spindle which I haven't tried on aluminum yet.

In other words... Cutting too deep, moving too fast and spinning way too fast!

If you do the math you should be able to get good cuts even with a router. The feedrate = no. flutes x rpm x chipload. For a 1/4" bit I use a chipload of .0025-.003". With my SuperPID on the router setto 12krpm that equals 32-36ipm per flute. For my router I pocket at 1/2D for pocketing and 1/4D for slotting. You should use some sort of lubricant to keep the aluminum from galling. The jey is using the highest speed you can with the largest chpload your machine can handle, so the heat is on the chips not the work. I can hold my endmill after a job.

Also, cast and ground aluminum plat (mic6) routs easier since the chips break up nicely. If your chips look like powder you're just wearing out your endmills. If you have to route at high rpm I've been suggesing single edge spiral o flute bits for years, they work great at high rpm. Then you can switch to a 2 or 3 flute for the finish pass if needed.

[ger21]

Steve, I feel like I'm high jacking your thread...Gerry, are you using coolant?

No, I was cutting cast plate, and cutting dry.

[Spk64]

I am cutting 6061 T-651 right now. Cutting with a kool mist mainly to keep chips cleared but adding just a small amount of coolant.
Cutting deep slots need to keep chips out to avoid recutting chips.


Steve

[bobmagnuson]

... adding just a small amount of coolant.

What's a small amount?

[Spk64]

Can barely see the mist.



Steve

[bobmagnuson]

Thanks. What type of mist system are you using?

[Spk64]

It is Trico mist system. Not sure it is a required item. But let's it run without me babysitting.


Steve

[bobmagnuson]

I'll have to investigate either a mist or droplet system next time I have to cut aluminum. Sure would be less messy than spraying wd-40!

[Spk64]

I have had my Trico for about 25 years Still going strong.
Finished up 3 more groups of brackets this afternoon.
Attachment 267116

[bobmagnuson]

Nice! I've been reading a little about the misters, etc. Do you get any 'fog' in the shop or oily over spray?

[whimsical]

try metho as a coolant.
We used to cut miles of ally, even the soft sticky types, and it works very well. Just make sure there is plenty of ventilation or you will get a serious headache after a few hours.

[Spk64]

In the 30 years of using the misters in my own shop and at a job shop we never had a fog problem. We always ran them fairly low air or low on the coolant so as to not flood the air or machine.
When I am cutting on the router there might be a teaspoon of fluid on the parts.
It is coolant mix so there is some residue from that.




Steve