Compact linear slide ideea

[pupetxls]

Hello everybody,

I'm looking for an advice, maybe somebody bumped his head with this before me. Don't really wanna reinvent the wheel. Done it too many times allready.

I'm building a router for plastics. 2.5D, cutting sheets up to 10mm tops. But it's a big one 8.2 by 5 feet workarea.

Rails this long are quite a value. So I'm looking into the diy area abit. Though, I'd like a compact design for the linear system.

I have 3 ideeas, all in the attachemts too:
a) - using some sliding pads (UHMW, Delrin etc). Small pads with 1mm groves in it to reduce the friction surface, and placed as far as posible from eachother to improve rigidity. One pad should be like 20mm in lenght and 10mm wide. 2 of them per profile. Forgot to mention, they'd slide on aluminium extruded profiles, just flat with the grooves on the surface. (no guiding)
I'm affraid here about the force needed to start the motion. That's quite high, and goes down once it's started moving. Really wouldn't wanna miss steps because of it.
b) - diy-ing some recirculating balls system. See the attach. I'd mount a set in each direction to close the side movements.
c) - the regular bearing rolling on the flat surface. No questions here.

Just don't mention V grooves. Sick and tired of them. Don't wanna go into this saga here.

It's a belt driven system, but though speed are not quite as high. Rapids would go tops 50mm/sec. Weight would be no more than 2kg/slide piece.

Any advice would be highly apreciated.
Thank you in advance,
Pupet

[RomanLini]

2kg per slide bearing is pretty trivial weight and the friction won't be bad, a stepper and leadscrew (or rack/pinion) will move that easily.

I think your big problem will be wear over time. Anodised aluminium will be much better than plain extrusion. If you build in some adjustment to compensate for wear it should work pretty well.

[louieatienza]

Those recirculatung tracks you made for the drawer slide are pretty darn cool!

How about 1/2" c-channel and hdpe runners?

[pupetxls]

Hi there guys,

Thanks for the words.

@ RomanLini - I actually had to look up for "trivial" to see in which form of the word do you mean it . considering the size of the runing path, screw'n'nut is pretty much out of the question. (rotating the nut on fix screws, seems complicated)
I'd prefer belts, but probably it'll be rack and pinion system.

@ louieatienza - that's not mine actually. It's just an image found on random google-ing. I hope I'm not creating an authors rights issue in here. Just posted it as DIY viable option. Though in my case, I got to the conclusion that the balls would eat up the aluminum quite fast, and make themsleves a nice U chanel in time.
Didn't quite got your idea with U and HDPE. I had some idea not long time ago, for a reversed V rollers. V chanel in the aluminum, and reversed V on the rollers. The problem that put the ideea on hold was the dust getting into the channel.

All and all, I decided to go along with the plain bearing just on the flat surface. They'll support the weight. And I'll use UHMW pads for anti side movements. Of course, adjustable.

One more time, thanks,
Pupet