Shapeoko cutting metal

[PLHS54]

Do any of you guys have any videos or experience with the Shapeoko cutting metal?

[nasa nate]

I was wondering the same thing..

[edwardrford]

This quote is from another thread (viewtopic.php?f=4&t=162&p=1258#p1258)

... I expect the Shapeoko will need some "smart" stiffening to cut aluminum and smoothing the current steps would also help. This is still to be tested as near as I can tell. ...

Instead of hijacking that thread, I'll reply here:

I was cutting aluminium plate yesterday, with my Shapeoko. I cut a 4" x 4" x 1/4" piece of aluminum plate, from a larger piece, to 'experiment' with. Playing with different pass depths and feed rates. Here are some notes I kept of the process.

Overview:
- 2 flute 1/8" endmill.
- Depth pass was set to .0125"
- stepover was set to .0625" (50% of bit diameter)
- incrementing depth .0125"
- Feed Rate was set to 12in/min
- generic dremel turned on high (30k RPM?)
- liberally applying WD40 as the job was being cut

At one point I was running 60ipm
- taking *very* shallow passes (0.002").
- stepover set to .03125" (25% of bit diameter)

Some other things to consider:
- would more flutes help? Would less flutes?
- is WD40 (or any lubricant) necessary?
- (deeper passes + slow speeds) vs (shallow passes + higher speeds?)

[BrianH]

Can't wait to get my shapeoko to experiment with. Here's a good article on cutting aluminum:
http://blog.cnccookbook.com/2012/03/27/ ... g-success/

[bkgable]

That is an excellent reference. Thanks for the pointer.

After reading that I conclude two things from my experience with a mini-mill.

1. The bending forces on the structure depend on the width and depth of cut. Making 0.010 cuts is much easier than making 0.1 cuts. On the mini-mill if I want to make a 0.4 pocket then I tend to make 2-3 passes at 0.20 per cut. Which doesn't stall the 500W motor but does set up resonances. But with CNC the controller would be happy to make 40 consecutive 0.010 cuts. I just turn it on and come back in an hour. Anybody tried that yet?

2. Cutting on the min-mill is very sensitive to spindle rate. I'm continuously adjusting it so that it sounds good (not a method recommended in the reference ) . I learned from cutting aluminum on a miter saw that using a router speed controller to reduce the saw speed makes the cut more controllable. Doubt that using a router speed control with a Dremel would work too well. But maybe with a laminate router.

Does anybody else think this problem seems to have too many variables?

[Frankenbeans]

My primary intent with my Shapeoko (when it arrives, omg soon please) is to cut aluminum. Sure, I'll be cutting other stuff, but aluminum is my main goal.

Anyway, to help accomplish this I've been building an airbrush based isopropyl alcohol misting system for it. Isopropyl doesn't flash easily, and can be combined with enough water that it still produces a sufficient cooling effect on the work area while reducing the chances of ignition. It also has the benefit of creating a fine slurry of aluminum that's easily removed by the cutting head. The amount of mist that's generated by an airbrush is variable too. Mine sprays "lots of small droplets" rather than a vapor.

I found this method over here http://romaxxcnc.proboards.com/index.cgi?board=discuss&action=print&thread=321

Now all I need is my Shapeoko to get here.