James's lr3 build

LowRider CNC Your Builds
1

I finally completed the build after a year

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The x,y,z works and all switches works after compiling marlin 2.1.1 on a mks gen v1.2 board with a4988 stepper drivers(5)

Only one glitch is both z axis rods are not perfectly parallel it gets too tight and jams as it tries to reaches few mm of bottom

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I measured the offset it’s about 1.5 mm out of alignment I think the linear rails i bought may not be exact thickness as the linear rails on the v1 engineering website that may affect it so I’m thinking of shimming to move bottom motor housing but outward or raise lunar rails 1 mm higher from the surface ? The left side is worse tighter

4 Likes
2

Have you tried lubricating the Z axis rods? Mine kept binding near bottom. Sprayed some wd40 dry lube and that fixed my issue. Someone more knowledgeable maybe able to provide some insight but the coupler should have a tolerance for misalignment.

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i did with silcone spray but its too extreme of alignment over half mm minw is 1.5mm

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you did have similar issue to mine hmmmmm…

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If you’ve already tried the lube idk that more would change anything. Did the Z axis ball bearings move freely? Is it possible one of them is miss aligned and that’s were your offset is coming from?

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It’s the xz plate and z motor mount not equal offset it should be the same for z rods I suspect linear rails different thickness even I ordered exact same # as listed in the part list

7

It looks like the stepper motor is not mounted parallel to the wood (or perhaps it’s an optical illusion).

Is the motor mount fully seated at top and bottom? Can you use a builders square to check if the edge of the motor is indeed parallel to the YZ Plate?

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I will check in the morning since our power is out in the area

9

After looking closer I concur it looks slightly askew. Also make sure your couplers are seated below the level of travel your second photo looks like the top of the couple in in the way of the window.

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2nd photo is the left side thats the issue …

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I’ll be damned you are right it had shifted higher …

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Yep
Image_2023-10-15 12_19_31_004
A little too forward the motor shaft center the top needs to move back a bit
The photo was taken using USB c bore scope bought off temu

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At least it’s an easy fix!

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that coupler already been corrected but still same issue its the center to z rod alignment as seen in the borescope photo

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I would make a thread/topic under the troubleshooting section as that will get more attention from those that know more than me

16

Since you printed your own parts the Z steps on your printer could be a bit off, or really crazy elephants foot?

An easy fix might be add a couple washers under the Z bearing blocks to back that up a bit, or you could do the linear rails as well. Haven’t seen one off that far.

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from the look i might remedy that by moving z motor mount 1/2 mm back by loosening 4 bolts and shifting it back and tightening bolts

18

Problem solved it nows works perfectly but I couldn’t upload video directly

2 Likes
19

That actually worked?!? I still do not see what was off, none of those parts are adjustable that I know of.

SO glad you got it figured out though!!!

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The plywood plate is modified with more clearance to let the motor mount slide 1/2 mm back simple as that