Finally got a chance to pull it apart. (I swapped one of the Y’s with the X to get by).
Arnold’s video was helpful, but incomplete and also a couple things wrong.
I didn’t have time to make a video but I took a couple pictures.
Here’s the procedure (note that this is how I did it and not official. Since all I got from support was “Need to adjust the sliders” and “it’s difficult” I’m considering that as sufficient instructions that I can proceed without voiding my warranty. Proceed at your own risk)
Find a clean place to work. While there was some sawdust already since I’ve been mostly doing cnc work (the strips do a pretty good job but they aren’t dust proof), you want to keep as much dirt and debris out as possible.
You need a 3mm hex bit besides the bits that come with the SM supplied screwdriver.
You can follow most of this through Arnold’s video.
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Slide the bracket away from the cable end.
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Remove the 4 screws that hold the strips on. There are two little rectangular pieces that are used to keep the strips tight. (do not lose these!) The strips will be loose so be careful that you don’t bend or damage them. They’re pretty sturdy, but still.
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Remove the 8 screws (4 on each end) that hold the end caps on.
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Carefully pull out the end with the cable. There will be two wires (B&W) that plug into the circuit board assembly. In the video he uses pliers, I prefer to use a spudger or just grab with two fingers and carefully wiggle and pull. (I’ve had more problems deforming soft plastic connectors than pulling out a wire accidentally. Also, It’s keyed so you don’t have to worry about remembering which way it goes in.)
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Continue to pull out the stepper motor assembly and screw until you have enough of the screw revealed that you can grab it with your fingers (In the video he kept turning the whole stepper assembly, but I think he said it had seized.) Make sure your hands are clean or wear gloves. Turn the screw CCW until it releases from the bracket and you can remove it from the housing. Set it aside where it won’t get damaged or dirty.
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Pull off the other end cap
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Slide out the bracket assembly along with the strip (I didn’t remove the strip. I don’t know how hard it is to get back in, you don’t need to, but again be careful)
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Now you’ve got the part you need to work on:
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Loosen the 2 small set screws that hold the eccentric nuts tight. (One on each side)
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This part I’m not positive I was doing in quite the right order or best way, but it worked for me. The way the eccentric screws is different than ones I’ve dealt with before. (The allen screws don’t just change the orientation of the nut but also need to be tight.) I loosened the allen screws (red arrows) with a 3mm hex bit. This turned the eccentric nuts (green arrows) which raise or lower the rollers. The rollers have markings to show how much they’re turning, but I just watched what it did from above and guessed. (You could probably use calipers and measure) I adjusted to my best guess of what was necessary and then tightened the set screws. Then I tightened the allen screws. (Note: I did this on two linear modules, and on 3 of 4 allen screws when they turned the eccentric nuts turned accordingly. On one I had to use a small screwdriver on the markings on the eccentric nut to turn it)
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Carefully take the assembly and fit it back into the housing. You’re just trying to insert and check the first set of wheels. They should fit snugly between the two rails (blue arrows). (Watch out for the limit switch (yellow arrow) Use a small screwdriver to hold it out of the way. There are several points where it will catch)
Don’t force it! It should be tight but not excessively. If it doesn’t fit, you need to readjust the wheels. If it does fit check if there is play. If it seems loose, pull it out and re-adjust. If the first two wheels seem right, then proceed with the 2nd set.
Again watch out for the limit switch. Again, don’t force it.
If it fits, go ahead and try sliding it. It should move smoothly without much force necessary. (You don’t want it to have play, but you don’t want to burn out the stepper motor by making it work too hard.) If it wobbles front to back (up and down) you need to adjust both screws tighter. If it rotates, the 2nd wheel is too loose and needs adjusting. -
If everything feels good and tight but still moving well, you’re ready to reassemble. Pretty much the reverse of disassembly except I put end cap back on just before re-fastening strips. Be careful when inserting the motor end that you don’t snag the wires when you’re sliding it in.
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Use the strip tension tool that came with your SM to tighten the strips. (Tighten each screw a little at a time to keep the rectangular pieces from rotating).
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Reinstall on your machine and check that everything moves and sounds right.
That should cover it. Let me know if there’s anything I missed or confusing or think I did wrong.
-S
Notes:
I didn’t do any lubrication. There was still plenty on leadscrew and everywhere that seemed like it was supposed to. I did blow out some sawdust and wiped away a little from one of the rails with a q-tip.
Some people have oiled the dust strips to get rid of squeaking. I think this isn’t necessary if everything is adjusted properly. It will only cause dust to collect and build up and cause problems down the road. (There may be a way to adjust tension on strip while doing this procedure. I didn’t need to so didn’t investigate)
While you’ve got it apart, check to be sure that the silicone pad that has been missing and causing early failure is present and properly placed:
