Y Plate Sag

Trying to track down that last bit of Z accuracy so I can cut rabbets… turns out the biggest source of error I have right now is sag on the Y plate on the side all the electronics hang off. It’s sagged almost 2mm compared to the other side throwing off my Z height. I’m able to compensate with a 2mm shim but wondering if anyone managed to solve this better?

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Well it looks like we have the main solve for the next revision. This is not the first time I have seen this. What all do you have on there?

Unload it as much as possible, did your MDF bend, or did the plastic parts warp (pla)? Maybe your bolts are just loose?

My original is still good, I have the vac hose hanging down about 3 feet, 12v6a power brick, Rambo and lcd. PLA parts.

That did give me an idea, I will need to sketch it out.

We need a high rider to follow the low rider with it’s electronics. We can just PR Marlin to add a mirrored board and call it DUAL_ALL_MOTOR. Or we could use Jamie’s double decker build.

I’m pretty sure it’s the ‘ears’ on the MDF bending with the weight… even if I just push with my fingers they flex. I will double check the bolts and PLA.

I have the power brick, a raspberry pi, rambo mini, screen, shutoff switch and electrical outlet mounted on 1/4" hardboard attached to the Y plate. The hose and power cable hang down off that side and I do most of my cutting on that side so there is usually the weight of the router as well.

High rider! Or maybe an Ultra low rider… have it crawl along a track under the table

im looking at a double decker are there any plans for this jamies one thanks

it looks like the best plates would be steel or aluminium, but if you have to use wood plywood is stronger than MDF and is a better choice

 

I am pretty sure Jeff was kidding – nobody has made a double-decker for LR2 that I am aware of. I have some half-baked STL files for the double-decker MPCNC here: https://www.thingiverse.com/thing:3709811

In particular I have hybrid rollers for 25.4 mm gantry and Z rails that fit with 23.5 mm side and leg rails, and I have corner pieces that allow the legs to extend vertically through the corners. I think the rest are all standard pieces for the double-decker MPCNC (mixture of 25.4 and 23.5) but I’d be happy to share other pieces if it turns out I missed something.

It isn’t double-decker in the same way yours is (with dual carriages and drive belts), but they did double up the rails to prevent Z rail deflection (at least that’s what it looks like).

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I did not know that! Interesting.

Wow that’s a lot of extra weight but certainly rigid. According to sagulator, plywood is indeed way stiffer than MDF. Maybe just recutting out of 1/2" baltic birch would help.

 

I’ve never seen that lowrider before!

Any solution to this? I am having the exact same problem.

Using 1/2 MDF

Use plywood.

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Just a followup… I was able to measure the Y plate has a twist of about two degrees on the ‘ear’ and was straight in the middle part so I cut new plates from baltic birch plywood and took it apart… I put a square to the Y rollers and it looks like the PLA has deformed slightly over time and are no longer square. In the process of reprinting them in PC+

Here’s my results… The pipe clamps at the very top are PC+ so I can really tighten them without breaking. The two pairs of pipe rollers on the Y plates were reprinted with PLA at 95% infill since it’s stiffer than PC. The Y plates were re-cut out of 12mm baltic birch. It’s way stiffer now but you can see there is still a slight sag. A toe-in problem I was having with the wheels is gone now. I notice someone on thingiverse made some mounts for horizontal rollers that push on the side of the table instead of wheel guides. I think that would probably take some of the twisting force off the wheel mounts.

I printed a few extra pairs of baltic birch Y plates while I was at it… willing to sell them at a fair price if anyone needs em.

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I am considering building my first lowrider to CNC cut model railroad pieces. I would be interested in buying your birch Y plates.

Alan Smith
Cheshire, Connecticut 06410

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