New CoreXY Design - Mounting Linear Guide Rail on Aluminium Extrusion

I was hoping to get some advice on mounting some MGN15 linear rail onto some Bosch Rexroth 40x80 aluminium extrusion. A picture is a thousand words, so please see attached.

The 40mm extrusion has a 10mm slot, which doesn't leave very much metal for the 15mm wide rail to sit on.

What's the best way to resolve this ? I don't want to have to get a piece of solid aluminium box section machined for all of the holes that the rail needs.

I've also attached a work in progress picture of my design so far, if anyone's interested.

Edited 1 time(s). Last edit at 03/12/2017 07:42PM by yngndrw.

I milled a 0.25 mm deep channel in the surface of the t-slot extrusion to provide a flat surface for the guide rails in the Z axis of my printer.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thanks Mark, that would give me another couple of mm by removing the funny slot edge from the extrusion and would stop the rail from slipping off the slot while assembling.

Would the rails be okay with just a total of 5mm width of metal behind them ? I suppose there's not a huge force behind them. I'll also have to make sure the fixed pully and notor blocks are corrected for the new height as I was going to use some 15mm high box section to space them up to the bearing block height.

I was hoping to not have to do any milling of the rails as I don't have a milling machine, but I might have to send them off.

You could just bolt pieces of tooling plate to the extrusions and mount the rails on the tooling plate.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Good idea, at least then I only need to drill holes.

I'll have to continue with the design and see how it all fits together.

Thanks.

Pretty sure you can get away with just bolting it to the 4040 direct, i'm not even using all the screw holes.

I suppose the only way I'd know for sure is to try it. I had a look for some aluminium tooling plate in the UK earlier and couldn't really find any - I wonder if it has a different name over here ? Then again I can't machine it myself so I could pay someone to source the necessary materials and machine it. I'll make sure the design works with and without a plate, then I'm covered.

[www.alloysales.co.uk]
Look at EcoCast

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thank you, they have a good range.

none of this is needed. if you mount the rail into a slot you dont allow it to be able to be adjusted for parallel.

The slot is wider than the rail which allows adjustment of its position within the slot. If you don't give the rail a flat surface to sit on you may create twisting forces on it when you screw it down to the unflat surface.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

In my build, I am using 2040 extrusion with 10mm rails. That leaves about 2.5mm on either side that the rail is riding on. It seems to work fine. I think the T-Nuts pull up on the aluminum extrusion just as much as the rail pulls down on it. Seems rock solid. Will know for sure once I start printing.