Y-Axis is making a "scratching" noise
 
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Y-Axis is making a "scratching" noise  

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Bavilo
(@bavilo)
Eminent Member
Y-Axis is making a "scratching" noise

Hi everyone,

during assembly I have already noticed that one of the Y-Axis rods has some sort of groove. I would have to rotate the bearing to a certain position or else it would catch on this groove and make a scratching noise. After rotating all bearings to the correct position and fastening them I was able to move the Y-Axis without any noises.

During the calibration though, the Y-Axis still makes some sort of scratching noise when it is at the very back.

You can see this in this video:

I believe this could be related to a faulty rod or bearing. What do you guys think? I already send a message to the support, they will hopefully get back to me on monday.

Thanks!

Respondido : 25/03/2017 4:59 pm
StephanK
(@stephank)
Reputable Member
Re: Y-Axis is making a "scratching" noise

Well. first of all, the bearings and rods a couple of us MK2 users received were indeed rubbish. I got yelled at for saying so in the past, but it is what it is. Supposedly, the MK2S edition now has better rods and bearings (which kinda proves my point that the MK2 ones were less than stellar at times). Anyway.

The level of noise during calibration is rather loud - even with high quality bearings like Misumi or Igus bushings. There's also some considerable vibration & resonance not just scratchiness going on. That's to be considered normal.

Looking at your video, I am tempted to say it sounds all right.

But: if your rods show signs or increased wear or some sort of or groove, then something might indeed be off. Smooth rods should be perfectly smooth, hence the name. Maybe try to take a picture of this ridge? Is it an actually indentation you can feel or is it just a "polished" spot?

Also, did you try adding some grease to your bearings and rods? Best practice for ball bearings would be to wash them out and pack with grease before install. Sometimes just adding a bit of lithium grease onto the rods is enough as well.

Respondido : 25/03/2017 9:12 pm
Bavilo
(@bavilo)
Eminent Member
Topic starter answered:
Re: Y-Axis is making a "scratching" noise

I will try to take a picture tomorrow. I will also try some lithium grease!

Thanks!

Respondido : 25/03/2017 10:01 pm
david.s30
(@david-s30)
Active Member
Re: Y-Axis is making a "scratching" noise

I spoke through email to one of the Misumi engineers and he said that they recommend the following grease. I have one on order and should be here next week. Ill provide feedback when I receive it.

https://www.motionindustries.com/productDetail.jsp?sku=03760972

One more thing after watching your video, remove your bearings, grease them a little and make sure the bearings in the middle are aligned. The bearings need to be in a row, perhaps during use they have become out of alignment, If you can order the MK2s upgrade kit, the U bolt in the kit is a lot better design then the Zip tie.

Respondido : 26/03/2017 1:52 am
Bavilo
(@bavilo)
Eminent Member
Topic starter answered:
Re: Y-Axis is making a "scratching" noise

I do have the MK2S kit. And sadly I can't take a detailed enough picture of the rod...

I guess I will wait until monday.

Respondido : 26/03/2017 12:15 pm
Bavilo
(@bavilo)
Eminent Member
Topic starter answered:
Re: Y-Axis is making a "scratching" noise

Disassembled the Y Axis today and took a look at the rods and bearings. One of the rods is definitely faulty, it has deep grooves, I even cut my finger on a splinter!

I cleaned the bearings as well and flooded them with teflon spray. After putting everything together, the scratching noise is actually even worse then before. The bearings aren't a tight fit and vibrate with each movement.

I guess some thick grease could make this less noisy. Thought?

Respondido : 26/03/2017 9:23 pm
StephanK
(@stephank)
Reputable Member
Re: Y-Axis is making a "scratching" noise

For now, i guess you could try to rotate the rod in such a way that neither of the 4 lines of balls come near the defect. I would also send this picture to Prusa and ask for a new rod. Don't forget to mention the splinter thing.

The question i guess is, did the rod get damaged by a broken bearing or was it like that from the get go.. If it got screwed up by the bearings, i'd ask for new ones as well.

I use grease, i have no experience with teflon spray on ball bearings. Grease helps to a point, I fixed my bearings problem by tossing Prusa bearings & rods for brand name bearings.

Respondido : 27/03/2017 2:13 am
Bavilo
(@bavilo)
Eminent Member
Topic starter answered:
Re: Y-Axis is making a "scratching" noise

Prusa is kindly sending me new rods and bearings. Will see how that goes. If it still doesn't get better....
I will be getting:

RJZM-01-08: http://www.igus.eu/wpck/2292/drylin_r_rjum_01
AWMP-08: http://www.igus.eu/wpck/2335/drylin_r_awmp

Respondido : 27/03/2017 11:59 am
Marc
 Marc
(@marc-9)
Estimable Member
Re: Y-Axis is making a "scratching" noise


RJZM-01-08: http://www.igus.eu/wpck/2292/drylin_r_rjum_01

Be aware that they have an outer diameter of 16mm instead of 15mm!

RJ4JP-01-08 are uncaged with 15mm outer diameter
RJZM-02-08 are caged with 15mm outer diameter
(RJZM-02 are RJUM-02 series but "Nominal widths under 10 mm are supplied with press-fitted cylindrical bearings")

Respondido : 27/03/2017 12:48 pm
Bavilo
(@bavilo)
Eminent Member
Topic starter answered:
Re: Y-Axis is making a "scratching" noise

Thanks! I will get RJZM-02-08 then!

Respondido : 27/03/2017 1:25 pm
Marc
 Marc
(@marc-9)
Estimable Member
Re: Y-Axis is making a "scratching" noise

A friend and I just ordered the RJZM-02-08 and we will check how their subjective behaviour in comparison to the RJ4JP-01-08 will be. I expect them to have a smaller clearance because they are caged and at final tolerance where on the contrary the RJ4JP-01-08 should be mounted press-fit.

Strangely most posts discuss about the RJ4JP-01-08 or the RJZM-01-08 but about nobody mentions the RJZM-02-08. 😮 😯 😕

Respondido : 27/03/2017 4:21 pm
Bavilo
(@bavilo)
Eminent Member
Topic starter answered:
Re: Y-Axis is making a "scratching" noise

The RJZM-01-08 are press fitted as well, but they have an outer diameter of 16mm instead of 15mm

Respondido : 27/03/2017 5:02 pm
StephanK
(@stephank)
Reputable Member
Re: Y-Axis is making a "scratching" noise

No need to pressfit RJZM-01-08, that's why they come encased in an aluminium casing. Problem with RJZM-01 is indeed the outer diameter.

The reason why I went with RJZM-01 instead of RJZM-02 is simply because I didn't notice the RJZM-02 on the german Igus page when i ordered mine (and for some reason igus didn't mention them either when i talked to their sales rep)

Atm, i have a Franken-Mk2, RJZM-01 in the Bed, RJ4JP on X (which work just fine without a pressfit according to personal experience of 3+ months using them + Igus sales rep recommendation) and lastly, Misumi on Z.

Maybe i'll switch them all to RJZM-02 eventually. RJZM-02 seems the best match according to the specs. But atm this thing prints perfectly and very silently and I am a bit tired of taking it apart. I need to print stuff, not messing around with my printers. Overall, i already put in too much time to get to this point.

Respondido : 27/03/2017 11:50 pm
richard.l
(@richard-l)
Miembro Moderator
Re: Y-Axis is making a "scratching" noise

where on the contrary the RJ4JP-01-08 should be mounted press-fit.

Why do people still insist on stating this when it is absolutely false. These are specifically designed to not be press-fit. Direct from Igus..

Quickly installed, secured by circlips

Respondido : 28/03/2017 3:47 pm
Marc
 Marc
(@marc-9)
Estimable Member
Re: Y-Axis is making a "scratching" noise

@richard.l
They can be mounted with circlips BUT final tolerance will only be fulfilled if they are pressfit. Thats what's stated in the IGUS catalog descriptions on mounting details:

Respondido : 28/03/2017 4:04 pm
richard.l
(@richard-l)
Miembro Moderator
Re: Y-Axis is making a "scratching" noise

@marc

That spec is for the RJM not the RJ4 series of bearings. It is a totally different material. This is the catalog entry for the RJ4JP bearing.

Respondido : 28/03/2017 4:13 pm
Marc
 Marc
(@marc-9)
Estimable Member
Re: Y-Axis is making a "scratching" noise

Well then... 🙂

I will anyway see how the RJZM-02 will be because I already have them. 😉

Respondido : 28/03/2017 4:34 pm
Bavilo
(@bavilo)
Eminent Member
Topic starter answered:
Re: Y-Axis is making a "scratching" noise

I just intalled the RJZM-02-08 and the AWMP-08.

First of all, the RJZM-02-08 come with an aluminum housing, meaning they are press fit. But I do have to say that they are not 100% tight. There is some tolerance!

But in the end...No scratching. My Y-Axis has never been better!

Respondido : 31/03/2017 3:49 pm
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