MK3 - any chance of delivering a new bed frame in '23?  

How do these vibrations manifest?

Cheerio,

RE: MK3 - any chance of delivering a new bed frame in '23?

During the printing and Y axis movements, the bed starts to vibrate which causes an annoying and quite clear sound. However, it is enough to put something heavier in the right-front or right-back corner to stop the vibrations almost completely, just put your finger on it. After replacing the bearings with IGUS, the noise drops by half, but the problem does not disappear. Anyway, grab the bed frame and try to move it up and down, on the left side it is stiff, on the right side it is loose because it is supported by only one point.

My printer stands on a massive plate with a strong vibration damping foam under it, the ground is even, the printer is calibrated according to Prusa official suggestions on how to get rid of such vibrations.

How old is your printer?  Do you have the 'U' bolts or the bearing clips?

Cheerio,

RE: MK3 - any chance of delivering a new bed frame in '23?

I think it is a latest one, bought last summer.

So they look like the ones at step 21 on this page..?  https://help.prusa3d.com/guide/2-y-axis-assembly_165795

If so, loosen the screws on your four 'Y' holders, three on each iIrc, one turn each will do; *NOT the bearing clips* then, on the same page go to step 27 and follow the alignment and tightening procedure.

Cheerio,

RE: MK3 - any chance of delivering a new bed frame in '23?

Believe it or not, I'm not an idiot 🙂

I've done this many times with no effect. Thank you for trying to help me.

OK, we work through it stages - on that same page go to section 7 and repeat the loosen/retighten process.

After that we will visit at section 17 of https://help.prusa3d.com/guide/7-heatbed-psu-assembly_172872 in the same manner.

... and what are you using to lubricate your smooth rods?

Cheerio,

RE: MK3 - any chance of delivering a new bed frame in '23?

Nothing changed, really. I checked all the components, they seem to have the correct dimensions, especially the shafts. Everything is solid, even and straight. I also changed my IGUS linear bearings to original ones supplied by PRUSA for this exercise and relubricated the inside using CX80 lithium grease. After that, once more time I did step 21 and re-screwed the bed according to the instructions. The heated bed vibrates especially at higher printing speeds, the vibrations are minimal, you can't see it, just the sound is annoying. I've done some testing and this noise is mostly heard when the bed returns from the back to the front of the printer, strange.. My old ender 3 pro upgraded with linear rails and new board works much, much quieter, but there are also quieter stepstick's.

Loosen and retighten the right hand bearing clip, it probably won't help but it's an easy long shot.

Take obvious precautions during this next operation, it will be hot but not scalding.

Remove the print sheet, loosen the bed screws one turn as in the previous step 17, Heat the bed to 60 degrees (LCD menu) and let it stand for five minutes, run the Y carriage backwards and forwards a couple of times (LCD menu) then retighten the screws as in step 17 above while hot.

This should eliminate any thermal distortion.

Cheerio,

RE: MK3 - any chance of delivering a new bed frame in '23?

Thank you very much 👍 

I'll check it in the coming days, currently I have some prints to make and my printers work all the time.

RE:

the new solution tested by NewBeeDrone seems to be a 4-point mount (I don't want to paste links so that no one will accuse me of advertising). I'm wondering if it's worth spending another 150$ to import this frame from the US. 

I have one of these NewBeeDrone beds, it is made of robust Carbon fibre sheet, Cut to match the Prusa Y platform shape, , it has 4 LM8uu locations, mine came with bearings and clips fitted. 
On the top surface there were recesses cut to locate the bed spacers in an effort to  make assembly easier. 
this does make the Y axis a little more constrained than the three bearing Y axis Platform. 

Whether it makes $150worth of difference, is in the eye of the beholder. 
I have 5 bed slingers... 4 are original prusa, 
I don't plan on changing the other printers. I am partially deaf, so maybe i don't  hear what you hear...

As a test, you could try attaching a blob of Bluetac, or whitetac, (Posh modeling clay) to the underside of your y axis, and see if this changes the resonant frequency of the Y platform, enough, to save you $150

regards Joan

RE: MK3 - any chance of delivering a new bed frame in '23?

First of all, thank you again for all your comments and help, Diem you helped a lot, I appreciate it.

I spent half a day today disassembling the printer and looking for the cause. I made a simple gcode for testing and noticed that the vibration level change significantly depending on the temperature of the bed. I mounted a device for measuring the runout of the brake discs in the car on the printer, I know I'm hardcore 🙂 In fact, the frame gave up slightly after warming up, causing vibrations. I greased and positioned the bearings correctly, positioned the rods so the bed would move freely, then heated the bed to 90 degrees and left it for an hour. After heating, I started to move the whole thing on loose screws, pressing lightly to remove any stress. In the end I installed everything according to the instructions. It's much better, thanks!