View Full Version : Routing aluminum

03-14-2005, 02:27 PM
I'm considering cutting a small run of parts from 1/8" x 1 1/4" aluminum flat stock. It's just a small, rounded corner rectangle with 6 - 3/32" holes drilled in various spots.

I'd like to use my CNC router to do this with a 3/32" cutter of some kind. I'm going to have to buy the cutter so I'd like to pick the best one for the job.

Whatcha'll think? A 3/32" 2 flute carbide router bit or a 3/32 endmill of some sort. I'd like to plunge drill the holes 1st then cut the perimeter shape of the part with the same tool. I know the high speed (23,000) rpm router ain't the preferred tool but it's all I have and thought I'd give it a try. I've accidently cut aluminum with a carbide bit in a router and it seemed to cut fine.

03-14-2005, 03:28 PM
A 2 flute carbide router bit should work fine, you might put a cool mister on it and give a few shots of wd40 to keep it from chip welding on the cutter.

I have run a 3/4" router bit .250" deep in aluminum at 26,000 rpm.
I was making triangular pockets for pin guides in match plate patterns for a foundry.

I think chip weld is less of a problem with the 2 flute carbide router bit.

good luck.

03-14-2005, 11:03 PM
This is also my dream, to be able to cut aluminum with a CNC router. On a visit a couple weeks ago, to the big town of Pleasant Hill, La... I observed the prototype of my router doing a great job with wood, and dropped one of my favorite discs of 6061t under the 1/16" bit. We slowed the feed down to 10 ipm (from 50 for the wood it just did) and it promptly made about 1/4 of the letter "B" before breaking the endmill. Pretty sure it loaded up, since we were running it dry.
Might want to give a single flute a try, instead of a 2 flute. More strength, and less to load up. Keep it lubricated continously. (as mentioned by Mike)

Have gun, will travel.

03-14-2005, 11:25 PM
Hello Guys,

I have a CNC Router that I use for milling aluminum regularly
I use a dual mister and cut at about 40 IPM and spin the bit at about 2700 - 3200 RPM

I plunge at about 5 IPM

seems to work for me.

pretty much as good as a real mill for my needs.


03-15-2005, 06:23 AM
Thanks guys, your info is very encouraging! http://bbs.homeshopmachinist.net//smile.gif

My router table is a homebuilt and very slow (8 IPM wide open) so there's not much danger of overpowering the bit.

Gunny, is that 27 to 32 hundred rpm you're using or is it thousand. If it is hundred, how do you get it down that slow?

03-15-2005, 08:59 PM
Hope this link is right, I use a router speed control from harbour freight on a hand router. Best fifteen bucks I've spent
in a long time.
Steve D


03-18-2005, 02:30 AM
Hello there,

I am usuing a 10 HP Spindle on my router table.

With a Omron Nema 4x Inverter. Basicaly just a VFD

set it and go, I actually fire it up and adjust the RPM in my code

Fire the mister, the light, the vacuum table all through the code

I have a ShopCAM router


Paul Alciatore
03-18-2005, 02:13 PM
I have done work on aluminun and also fiberglass circuit boards with a router. It works great. The above suggestions are good. Two more:

1. ALWAYS wear eye protection. ALWAYS!

2. You might consider using a template. It shouldn't take too long to make and it will make your parts completely uniform with little further effort while cranking them out. My router has a set of bushings that fit around the bit and I can just use them to follow the edges in a template. Mine is not the plunge style but I suspect a hole the size of the bushing, in the template would allow positining a plunge router for a simple hole.

Oh, on your cutter, if you buy an end mill, be sure it is of the end cutting variety. Not all mills are designed to plunge in.

Just some more BS: When I was doing circuit boards I used a home made router table. I had a jig that allowed positioning a guide button the same size as my cutter (usually 3/8" carbide) directly above the cutter where it stuck out of the table. I would stack 5 boards and an exact size template and pin them together with three 1/8" holes and pins and then rout the outline in one step. The boards would be against the cutter and the template would ride on the guide pin. All boards would be exactly the same size and the work was quick as I could do five boards in less than a minute, including pinning and unpinning them. And it would do any shape board as long as you could tolerate an inside radius in the corners of the cutouts.

I love routers.

Paul A.

[This message has been edited by Paul Alciatore (edited 03-18-2005).]

03-19-2005, 12:22 AM
<font face="Verdana, Arial" size="2">Originally posted by GunnySnow:
Hello there,
I am usuing a 10 HP Spindle on my router table.</font>Hoo-ahh....now THAT'S a router! I'll bet that big feller just says gimme sumthin' else to chew up, I'm HUNGRY! http://bbs.homeshopmachinist.net//smile.gif That's awesome. My little trim router just nibbles along and irritates the stock away!