Your ultimate Spindle and axis motors

[LeeWay]

I think you are right to say they may be less complicated than linear ways and screws, but unless highly powered, I can see them useful in much but non contact cutting. That is unless you are talking very light high speed stuff.
I would suspect this would also be limited to aluminum and plastics cutting. The stronger mag field would attract too much swarf in steel milling.
Something like plasma, laser, printing etc.. would likely work fine with linear motors.
Milling with them seems to just be unwise given the cost, especially when they state for light duty.

I do like that design though.
A caged machine. That is cool. I see how swarf deflection would work to some degree. I would suggest that you use rubber mounts on the walls when securing it. I don't yet have any resonance in my machine, but that could be a problem and better to forecast it now than have to redo later.

[Swiss]

The stronger mag field would attract too much swarf in steel milling

That's fine for us. We only ever cut plastics and Alu.

for light duty

Yes, their power is my biggest concern. I'm keen to work out how much power I need for milling. My very rough guess, pulled out of my a** is that I'd want at least 100N (40lb) force for cutting with our 6mm dia tool. Looking at the specs for one of the lower powered motors, I can see that a pair of motors per axis will give me 130N continuous force, and 520N peak!

Someone else reckoned that the acceleration would be the biggest problem. For a 10kg table, a peak force of 520N would give me 5Gs acceleration, which is plenty for me.

Even if that's not enough, the most powerful ones in the range give 955N continuous force, and 3820N peak! Surely that's enough? The thing I really like about these motors is the almost total lack of moving parts. Nothing touches, nothing rubs, nothing wears out. Attaching the coils to the base, and the magnets to the moving axis means that even the wires don't have to move. They could be extremely reliable.

I would suggest that you use rubber mounts on the walls when securing it.

That's an interesting idea. I was thinking about the sanity of screwing it to the wall, but mostly I wondered if it might hard to do it without deforming the machine. Can you tell me more about the resonance? What specifically would resonate? Wouldn't a secure connection to the wall hold it tight enough that it wouldn't resonate?

Hugo

[Swiss]

Hugo, this machine sounds really fascinating - can't wait to see the finished product!

Don't hold your breath. It's still a total fantasy. I need to convince my company that it's worth building rather than buying. I'm pretty sure they'll see the point of building when they look at the prices of similarly speced machines.

hugo

[DIY-Guy]

Thanks for mentioning the NSK E3000 and tool changer, I think I'd like to check that out with the manufacturer!

Where do I look for bits for this thing? Any suggestions? I'm thinking of carving wood, plastics, plaster, and light metals.

Thank you!
DIY-Guy "Just a computer guy making the switch from soft-ware to hardware...."

[Swiss]

Where do I look for bits for this thing?

Doesn't it just take normal milling bits?

[Jason3]

Hugo - any success with convincing your company to go ahead with this project? Whenever I've looked into buying a machine rather than building I come to the same conclusion, that I can build what I need for a fraction of the price, and get exactly what I want that way too.

DIY-Guy - I should mention that I'm becoming wary of using the E3000 spindle with the 1/4" cutters in aluminium - I would consider this to be the limit of this spindle, proceed with caution. Probably would be fine in plastic, wood or plaster.

I get carbide 1/8" shank bits here:

http://stores.ebay.com/CARBIDE-PLUS_...dZ2QQpZ2QQtZkm

They come in a nice box, and most have the depth stop rings. I like the 1/8" 2 flute end mills from Kemmer precision. They work really well in plastic, with a nice smooth finish, and pretty well in aluminium too. I haven't tried them in wood or plaster.

For 1/4" shank cutters, I've been using p/n RV323-5504 from Enco (Atrax short 2 flute uncoated carbide) lately. Nice finish in 6061 aluminium, and cheap!

Jason

EDIT - yes, it just takes normal bits...

[DIY-Guy]

Originally Posted by Swiss Doesn't it just take normal milling bits?

Sorry. I'm just a computer guy, a newbie in the world of CNC. So I asked where to find bits of that size. I don't (yet) know a "normal milling bit" if it bites me.

Do you have any suggestions for where to look online? Maybe a few URLs please?

Thanks again!

DIY-Guy
"Transitioning from software to the real world, where machines rule!"

[Swiss]

DIY-Guy,
I live in the UK, so I wouldn't know where to go in the USA.

If you're cuttingg Aluminium, be sure to get a tool which is specifically designed for aluminium. It's a sticky metal, which will build up on the tooth, making it blunt, and eventually causing it to fail. The right tools will have a coating which prevents this build up.

Hugo