Print bed vibrations at high speed on MK2  

Re: Print bed vibrations at high speed on MK2

I'm getting the exact same problem. I just got and put together my MK2 kit a couple days ago. I've isolated the problem to my linear bearings having a significant amount of play between it and the shafts. You can actually feel the bed have some dead play when I either move it side to side and up and down.

As for other possibilities, I'm absolutely certain the bearings are zip tied fit enough to the carriage (Tried re-tying them with no change and it's nearly impossible to move them while in place). The y-axis rails are also parallel because they run smoothly from end to end when the carriage is disconnected to the y-axis belt and motor. The rattle still occurs when the heated bed is removed. So it's completely between the shafts and the carriage assembly itself.

When the XY calibration routine runs, every Y-axis move, which is relatively fast, rattles the entire bed. Basically I'm getting a mechanical resonance from the deadplay.

Does anyone know of a quick solution? Outside of trying to find replacement bearing/shafts? I'll make some micrometer measurements on the shafts to see if they are in spec.

EDIT: The shafts measure out ok on a micrometer. I pulled some linear bearings from an old machine to see if I can replace them. Turns out 2 of the 3 linear bearings were ok. One bearing had some significantly play that caused the problem. But, all four of replacement bearings from my old machine were not any better than the bad one. I swapped one that seemed slightly better, but no real change in the bed vibration problem. It just sounds a little different.

Re: Print bed vibrations at high speed on MK2

Hi guys,

I'm having the same problem. Also to deadplay i believe but it could also be that there is only one bearing at one side.

The deadplay is very very minimal at my machine i fear that it is needed to ensure smoothness.

Any ideas how to solve this ?

Thanks!

Re: Print bed vibrations at high speed on MK2

Hi guys,

I'm having the same problem. Also to deadplay i believe but it could also be that there is only one bearing at one side.

The deadplay is very very minimal at my machine i fear that it is needed to ensure smoothness.

Any ideas how to solve this ?

Thanks!

I manage to fix most of it since posting. I did a few things like making sure everything was square and spaced correctly with a caliper. I also made sure all of the feet and frame are touching the table equally. (Even though having the frame touching the table is louder, it dampens out the vibrations more than having it up off the table.)

But, the best thing I did was buy some new linear bearings. A pack of 10 from amazon. I tested each one and found enough that were a tighter fit than the ones on my Prusa, which were extremely loose. Once I put them on my Y-axis bed, the loud rattling went away.

Re: Print bed vibrations at high speed on MK2

I was actually having this issue too. I thought I was the only one until I saw this thread. I ended up just cleaning the shafts and then oiling them with Hoppes gun oil. I moved the bed back and forth and the rattle went away. This rattle must throw off the calibration if just by a little. I wonder if I have to redo the xyz calibration as well as my squish is good in some places and is high in some places.

Is there a video on how to fix this?

Re: Print bed vibrations at high speed on MK2

I was actually having this issue too. I thought I was the only one until I saw this thread. I ended up just cleaning the shafts and then oiling them with Hoppes gun oil. I moved the bed back and forth and the rattle went away. This rattle must throw off the calibration if just by a little. I wonder if I have to redo the xyz calibration as well as my squish is good in some places and is high in some places.

That's interesting that oil helped. I bet it absorbs the vibrations enough to not make it rattle a lot. I did notice these new bearings I put into my machine has better lubrication. But, my bearings were so bad that I had a few millimeters of up and down dead play on the heated bed. I think I just got a bad batch of bearings. There's not much Prusa Research can do that I haven't already. No blame there. Still love this amazing machine.

As for high and low spots, I've found that the heated bed material (looks like FR4) isn't the most flat stuff. It's by nature curved and can be made worse when heated unevenly. I think it's the primary reason why there is a 9-point bed calibration for the Mk42 bed. But using FR4 allows you to make custom heating circuits and the really cool sensor points that can detect xy skewing. It's a design trade for the better.

So, I'd first make sure to get your y-axis frame very square and flat. Try to use calipers if you have them. A 6" one is just long enough to measure the width to the corner blocks and 100mm offset from the back to the frame. And, then re-run your XYZ calibration once set. I do this every time after I mess with the machine frame. Also, pre-heat your heated bed at the right temp for a few minutes (upwards to 10minutes if heating to 100C+) before you start a job. Things can still thermally move if there is an uneven temperature gradient. The pre-heating just makes it so everything is at a steady state.

Re: Print bed vibrations at high speed on MK2

I manage to fix most of it since posting. I did a few things like making sure everything was square and spaced correctly with a caliper. I also made sure all of the feet and frame are touching the table equally. (Even though having the frame touching the table is louder, it dampens out the vibrations more than having it up off the table.)

But, the best thing I did was buy some new linear bearings. A pack of 10 from amazon. I tested each one and found enough that were a tighter fit than the ones on my Prusa, which were extremely loose. Once I put them on my Y-axis bed, the loud rattling went away.

Would you be so kind to share the link to amazon where to buy these bearings or their name(code).
Many thanks!

Re: Print bed vibrations at high speed on MK2

Hi, new from Sydney, Australia and I am trying to get the print of bedding and bed but it is giving error while large size prints. Should I go for 3D print?

Re: Print bed vibrations at high speed on MK2

I guess I am having the same issues. When moving the bed at higher speeds i.e. travel moves i get a very loud rattle and strong vibrations and the movement doesn't seem terribly smooth. Moving it by hand or slow moves during printing are fine.

Two of the bearings seem to have alot of play and sit very loosely on the smooth rod. If I go into silent mode it's ok and print quality is fine despite the noise.

Is it worth asking support for a replacement? I was considering replacing bearings with Igus drylin RJUM8 and the matching rods since I am always fighting dust in here anyway..

Not sure what to do. Any suggestions welcome.

Re: Print bed vibrations at high speed on MK2

This seems to be one of the most common problems on the forum now, and I'm glad I wasn't the only one with this problem.

Based on my readings of other posts, and my own experiences, I do believe the problem is with the bearings that come with the printer.

So far, here are the options that I found for myself:

1. Suck it up and deal with it, since everyone seems to sell the same cheap LM8UU bearings.

2. Switch it igus Drylin bearings - Note that these bearings are designed to have a firm interference fit, and do not work as intended when simply zip-tied - this is the main reason these bearings are not recommended.

3. Find higher quality linear ball bearings - I ended up going with some ridiculously overpriced and fancy bearings from SKF with 8 races instead of just four, and so far they've been fan-tas-tic, but they also cost about a quarter of what the printer itself cost (almost 20USD each), so this is not a reasonable solution. I simply got frustrated trying to find reasonably priced bearings that would work correctly and gave up.

I've also ordered some replacement precision smooth rods from MISUMI.

It's important to note that none of this is really PR's "fault". They are shipping a cost-effective kit, and they certainly can't afford to include 100 dollars worth of smooth rods and 200 dollars worth of bearings.

In my opinion the kit as-shipped is probably "good enough" for most people's needs, but I imagine there those of us here who ask for a bit more, and so we get to pay more. 🙂

Re: Print bed vibrations at high speed on MK2

2. Switch it igus Drylin bearings - Note that these bearings are designed to have a firm interference fit, and do not work as intended when simply zip-tied - this is the main reason these bearings are not recommended.

My understanding to this point is that the tan IGUS bearings are not recommended for the reason you specify, but that the gray ones -are- acceptable as a direct replacement for the LM8UU bearings.

So -- don't use these, as they are designed to be press fit:

http://www.igus.co.uk/wpck/2292/drylin_r_rjum_01?C=GB&L=en

But I've read of people having good luck with these:

http://www.igus.co.uk/wpck/15862/N16_06_08

I've just ordered some to try on my noisy Y-carriage. Here in the US I ordered from Folgertech:

https://folgertech.com/products/igus-rj4jp-01-08-8mm-linear-bearing-to-replace-lm8uu

John

Re: Print bed vibrations at high speed on MK2

2. Switch it igus Drylin bearings - Note that these bearings are designed to have a firm interference fit, and do not work as intended when simply zip-tied - this is the main reason these bearings are not recommended.

My understanding to this point is that the tan IGUS bearings are not recommended for the reason you specify, but that the gray ones -are- acceptable as a direct replacement for the LM8UU bearings.

So -- don't use these, as they are designed to be press fit:

http://www.igus.co.uk/wpck/2292/drylin_r_rjum_01?C=GB&L=en

But I've read of people having good luck with these:

http://www.igus.co.uk/wpck/15862/N16_06_08

I've just ordered some to try on my noisy Y-carriage. Here in the US I ordered from Folgertech:

https://folgertech.com/products/igus-rj4jp-01-08-8mm-linear-bearing-to-replace-lm8uu

John

Do you happen to know where you read/heard when to use which? The first link is actually the version of the bearing that includes a hard aluminum housing around the bearing, whereas the second link (and the one you bought) does not have this housing.

According to Tom here ( ) he received a sample kit from igus with some info, and the polymer bearings are supposed to be press-fit into a tight housing with some real pressure, and not zip-tied. My understanding was that the versions with the metal housing do not need such a press-fit.

Because of the conflicting info I decided to call igus and speak with one of their technical engineers. They advised that the part number you linked to is an exception, and that you CAN use it without a press-fit, and advised that the tolerance was up to +.04mm. Not as good as high-end ball bearings (maximum tolerance on the SKF I mentioned is +.0018mm) but probably still better than the super-cheap LM8UU's (if someone can find the OEM datasheet for these it would be helpful). 🙂

All this to say, you should be okay. I am now considering ordering some of the same bearings to test myself. 🙂

Re: Print bed vibrations at high speed on MK2

Do you happen to know where you read/heard when to use which?

The font of all knowledge, Facebook. 😀

https://www.facebook.com/groups/Prusai3users/permalink/633291590188659/

Because of the conflicting info I decided to call igus and speak with one of their technical engineers. They advised that the part number you linked to is an exception, and that you CAN use it without a press-fit, and advised that the tolerance was up to +.04mm.

Thanks for taking the initiative to contact Igus!

I, too, had shied away from these based on Tom's video. After reading many of the Facebook posting over the past couple of months, I decided to take the plunge and ordered some yesterday. That, and the fact that I could hear the fast, long Y-carriage movements from two floors above my printer... 😳 I need to do something.

John

Re: Print bed vibrations at high speed on MK2

Here's another discussion where people are talking about tolerance issues related to igus bearings that are not installed with an interference fit: http://forums.reprap.org/read.php?279,136509,143287#msg-143287

I'm ordered a set as well, and will measure the ID of the bearings with my Mitutoyo calipers when they arrive. 🙂

Re: Print bed vibrations at high speed on MK2

Here's another discussion where people are talking about tolerance issues related to igus bearings that are not installed with an interference fit: http://forums.reprap.org/read.php?279,136509,143287#msg-143287

Look at the date on that post. The supposedly acceptable bearings just started shipping in the last year, as far as I know.

I'm ordered a set as well, and will measure the ID of the bearings with my Mitutoyo calipers when they arrive. 🙂

It is a relatively cheap experiment. The other cheap experiment is just to purchase a bag of 10 bearings and try to find three that work acceptably on my Y-carriage.

http://www.ebay.com/itm/12-Linear-Bearings-LM8UU-8MM-RepRap-Prusa-Mendel-DIY-CNC-Motion-/181168182751?hash=item2a2e7715df:g:OhoAAOSwmUdUWwd3

And there are many other cheaper eBay sales for LM8UU bearings too.

John

Re: Print bed vibrations at high speed on MK2

Ta da:

Click the P/N for the OEM site, click the price to go somewhere and spend too much on them. The igus drylin bearings may be the best bet for most people. I've just ordered some and I'm going to compare them to others.

1. SKF LBBR8-2LS/HV6 : 19.52USD

2. KH08-PP : 15.77USD

3. VXB LM8UU : 10.37USD

4. igus drylin RJ4JP-01-08 : 1.99

Re: Print bed vibrations at high speed on MK2

I installed my Igus Bearings for the bed today. Noise and vibrations are gone, i am very happy with the results.

As an added bonus, the Igus rods turned out to be black. While kinda pointless, i don't mind the new look.

Here's what i ordered:

3x RJZM-01-08 Aluminium cased drylin bearings (RJUM series - http://www.igus.de/wpck/2292/drylin_r_rjum_01 )
2x AWMP-08 330mm ( http://www.igus.de/wpck/2335/drylin_r_awmp )

In fact, now i want to swap the x axis bearings as well. Maybe next month.