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Steve
(@steve-7)
Trusted Member
Y axis squeeking

I have a new mk3s, and the y bearings squeeks.  It only squeeks in certain spots, and not over the entire rods.  Does anyone else have this problem, and what can I do about it?

Posted : 01/07/2020 1:05 am
morphias
(@morphias)
Estimable Member
RE: Y axis squeeking

Do yourself a HUGE favour and do the following:

 

A bottle of 100% (or as close to) isopropyl alcohol. You need it anyway and 5L is cheap.

 

Super Lube 21030 (the part number is important!) Find a local supplier.

https://www.mektronics.com.au/super-lube-multi-purpose-grease-3oz-tube.html

 

Then download and print these these:

Linear Bearing Grease Cap

https://www.thingiverse.com/thing:1128781

Linear Bearing Grease Cap Lid

https://www.thingiverse.com/thing:1134114

 

6 x M3x14 socket cap bolts (there's at least 4 in your spares bag)

 

Download and print 3 of these:

3DGussner X axis linear bearing holder

https://github.com/3d-gussner/Prusa/blob/master/Mods/Y-bearing-holder.stl

 

While your waiting for the alcohol and grease to arrive, do all the printing! Use PETG, a 0.4 nozzle  and 0.2mm layer height and 0.42 extrusion width for all extrusions. This make the threads and openings accurate.

Pull all of your linear bearings out. Put them in an airtight container with enough isopropyl alcohol to cover them by about 5mm. Give them a gentle tilt around, let them sit for 5-10mins and repeat tilting them around. Do this for 40-60mins to get rid of all the OEM oil.

Pull them out and shake out all the excess alcholol and then let them stand on their end on a couple of sheets of paper towel for about 30-60mins.

Get a bunch of paper towel sheets torn off in preparation as your fingers are going to get messy and it's a pain to get the towel after you have grease everywhere. 🙂

Get the grease cap you printed, put it on the tube, line the slots up with the calls in the bearings, slide the bearing on and then squeeze the tube till some grease starts to come out the top of the bearing. Do this to all the bearings.

Slide the bearing onto one of the smooth rods one at a time and slide it up and down about 20-30 times. You can wipe of the excess grease.

Repack the bearings again and repeat - this is important as I found out the hard way and hard to tear down my printer a second time to repack them. It's needed to work the grease through all of the balls.

Grab you new X axis bearing holders and use a craft knife to make sure the split is actually split all the way down and then install the 3 of the bearings into them. There are ribs in them that locate on the slots in the bearing body. It helps to have a small flat blade screw driver to spread the holders a little to get the bearings past the first rib.

Put your bed fram on a sturdy flat surface and push the bearing holders into their cutouts - orientation doesn't matter. It takes a fair bit of force, hence doing it on a flat surface. Use a small hammer with a piece of soft timber as a buffer to gently tap them down if necessary.

Once there in, press them back out again. You will find a tiny bit of the plastic has been shaved down in the intial press fit. See the attached pics. This needs to be carefully trimmed off with a sharp knife before final installation. They will go in a lot easier the second time.

Use the original nylok nuts from the u-bolts and the 4 spare M3x14 bolts from your spares kit. There are also 2 x M3x18 bolts which are too long to clear the heat bed. I used them and then just trimmed (good side cutters and a fine file) them down as I had no quickly accessible supply of M3x14 bolts.

Here is the beauty of the new bearing holders. They very accurately locate and align your bearings. No trying to be accurate getting them 50/50 yourself. Because the holder fully capture the bearing, there is no risk of overtightening them like you can with the u-bolts. In fact, you want to got quite tight to make sure the flat surfaces of the holders and the bed frame mate well.

Put your printer back together, run a full XYZ, belt and first layer calibration; knock to top off a cold one and enjoy the beatiful silence of properly installed, located and most importantly; LUBRICATED linear bearings!  🙂 👍 

Posted : 01/07/2020 2:57 am
StanHD liked
morphias
(@morphias)
Estimable Member
RE: Y axis squeeking

Geez - should have put that through Word to pick up the typos and bad grammar.  🤔 🤔 

Posted : 01/07/2020 3:10 am
Steve
(@steve-7)
Trusted Member
Topic starter answered:
RE: Y axis squeaking

Thank you for the info, and thank you for pointing out the typos.  I shall be more careful in the future.

I am shocked the bearing weren't properly greased before Prusa sent them out.  The manual claims that they are properly greased, which apparently they are not.  The squeaking didn't start until I started trying to calibrate the Z axis.  I tested it after I assembled the Y axis, and it did not squeak.

I am having great difficulty calibrating the Z axis and cannot get prints to stick to the PEI surface. 

I have a Flashforge Creator clone that I use, and I will use for printing out these parts.  I am no stranger to 3D printing.  I will typically use blue tape on the bed, and I thought the PEI sheet would eliminate that, but I guess it does not.

One thing I have noticed in assembling this kit is that Joe Prusa needs to find a mechanical engineer who knows about manufacturing tolerances.  I find the lack of adjustability for tolerances inexcusable.  I would write him directly, but I don't know how to do that.  My guess is that the squeaking is part of this.

Posted : 01/07/2020 7:48 pm
JoanTabb
(@joantabb)
Moderator
RE: Y axis squeeking

When I was unimpressed with my MMUv1 (Mk2 Printer)

I  sent an email to    info@prusa3d.com

I don't recall Joseph replying, but the issue was resolved... 

Have you tried applying grease from the kit, in a thin film on the smooth rods? it's a possible  temporary fix, for squeaking bearings. 

as suggested in Prusa Maintenance guide

https://help.prusa3d.com/en/article/i3-printers-regular-maintenance_2072#rods-and-bearings

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 02/07/2020 12:59 am
morphias
(@morphias)
Estimable Member
RE: Y axis squeeking

@stl

My apologies for for the misunderstanding! I mean my typos and grammar, not your!  🙂   I re-read it after I posted and saw them, but one super irritating thing about this forum is you only get a 5-10min window to edit a post.  🙁

 

I run -1.050 offset for the textured sheet and about -0.800 for the PEI sheet. I have no issues with adherence on either. Of course, the offset is different for every printer.

Initially, I did found that no amount of isopropyl alcohol before printing would get things to stick to either sheet until I washed them with hot soapy (any dishwashing detergent seems to work) water first. Now I don't need to use anything but alcohol for about every 15-20 prints and then hot soapy water again.

 

 

Posted : 02/07/2020 1:12 am
Steve
(@steve-7)
Trusted Member
Topic starter answered:
RE: Y axis squeaking

Thanks, but squeaking isn't mentioned in the Maintenance Guide.  I was on the phone with Prusa Tech Support for well over 2 hrs, and all they could suggest was to reassemble the Y axis, which I did 4 times.  I still had squeaking.  I am going to try the new Y axis bearing mounts (they were printed a bit too wide to fit into the Y axis frame but a bit of grinding with a Dremel will fix that) and pack the bearings with the lube and see if that doesn't make a difference.  If not, I'm just going to let it squeak and see what wears down.

I doubt that info@prusa3d.com will get me to Joseph.  Perhaps one day I will meet him at some show. 

I think the parts for my printer are a bit out of tolerance, which is why I am experiencing these problems.  In addition to the squeaking, the Y axis motor was a bit too far to the left, and the belt was running up against the left side of the motor pulley.  I fixed that by drilling slightly larger holes in the frame, and using washers to move the motor slightly to the right.  Now the belt is riding correctly.  Again, this is a tolerance issue, and Prusa doesn't give you any way to adjust things.

I can understand why the super large printer hasn't come out yet.  You can't scale this printer up:  It has to be redesigned.  The belt drive scheme with stepper motors is ok for small printers, but for larger printers, not so much.

One day, I am going to design and build a 600 x 600 x 600 printer using closed-loop servos and ball screws.  Putting together the kit was a learning experience.  Back in the day, I used to design flatbed plotters.  3D printers are a lot like that, except the printers have a Z axis.

I still can't get PLA to stick to the PEI sheet.  Perhaps I'll have to go back to using blue tape, like I do on my Flashforge printer.  No trouble with prints sticking to that.

I got the Prusa printer because I didn't want to futz with the printer: I just wanted to print things.  Now I regret the decision.  Should have gotten one of the Chinese printers and rebuilt that.  I just don't like the Bowden tube arrangement that they use.

Steve

Posted : 02/07/2020 1:37 am
Steve
(@steve-7)
Trusted Member
Topic starter answered:
RE: Y axis squeeking

For all those that have helped me.  The bearing holders I downloaded and printed from Thingverse have the same problem I have been discussing: Tolerance.  I printed them in PETG, and the fit is very tight.  I got them in the frame, and I believe one of them is slightly skewed because the side with the 2 bearings slides very rough.  There is no way to adjust the holders to compensate for this.  The holders should fit loosely, and the holes in the y carriage should be a bit bigger so you can adjust them bearings slightly when they go on the rods.

These bearing holders fit too tightly, and cannot be adjusted.  I am not going to make the holes in the carriage bigger.

What I am going to do is create another bearing holder that is a bit narrower and has bigger mounting holes (3.5 mm) so they can be adjusted to compensate for any skew that the bearing holder has.  I will then tighten the holders when they are mounted on the Y carriage, which will keep them aligned.

I am using the stl file for the bearing holder as a template, and creating a new one.  I use Alibre Design Expert.  I will then create a new .stl, print it,  and mount the bearings in that.

3D printed parts (at least on these low-cost desktop printers) don't have very tight tolerances.  The more expensive machines do, which is why they are more expensive.

Steve

Posted : 02/07/2020 10:24 pm
ashley3120
(@ashley3120)
New Member
RE: Y axis squeeking

Hey Steve don't know if you're still having the squeaking problem but have you tried taking out the y axis idler and greasing the sides that would touch the 3d printed idler holder? I was having a similar problem and the sound was from the idler rubbing against the 3d printed part. 

Posted : 07/07/2020 8:49 pm
pdh972
(@pdh972)
Active Member
RE: Y axis squeeking

You ever found what was causing the noise. Mine does the same thing in specific spots. 

Posted by: @steve-7

I have a new mk3s, and the y bearings squeeks.  It only squeeks in certain spots, and not over the entire rods.  Does anyone else have this problem, and what can I do about it?

 

Posted : 24/05/2022 5:39 pm
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