Re: Replacement bearings recommendation
Yes, I built my printer and have been testing it for about two weeks. The rods and bearings fro Misumi have worked out really good. The lengths I mentioned in my other post were exact lengths to the Prusas default shafts.
Smallest smooth rod: 8mm x 320mm
Middle smooth rod: 8mm x 330mm
Longest smooth rod: 8mm x 370mm
The Bearings glide very well on the shaft. They came nice and sealed in a plastic bag with plenty of bearing oil. Sadly I dont know what any other rods and bearings sound like as this is my first build and I have not used any other bearings or rods. I would love an audio sample or video if anyone has it. The Misumi rods and shafts are pretty quiet. The loudest component on my printer is the fan, which I think I am going to replace in a week or so.
I printed the dampening STL from Prusa and also placed a silverware drawer lining on the table I am using, under the printer and it helps cut down the noise substantially. What format can I post an image and I will post up a few of the samples I have printed so far. I think my 3D Benchy came out pretty good. The Triceratops skull is amazing, looking.
I had a bitch of a time getting my P.I.N.D.A sensor correct and getting the right Y axis length, but once I got that, all has been pretty smooth, minus the learning curve. I had issues with getting prints to stick to the heat bed, but Rave hairspray was 1.98 and works fantastic. But nothing so far related to the Shafts or Bearings.
Re: Replacement bearings recommendation
Very good to hear. I have got the same Misumi rods as you. But for bearings, I got the LMU-N8 variant without a dust seal. My Prusa kit arrived last week. I will try to put everything together this weekend.
For the dampening feet, are you sure that your printer will not hit its resonant frequency when you are printing something? If it does, the feet may actually cause a lot of stress be put on the printer. I do not know if this can damage it, but it is certainly not good for it. The best solution I have seen is to place the printer on a 16 inch by 16 inch garden tile (a heavy piece of concrete) to eliminate the resonance caused by a wooden desk or table.
Ales
Re: Replacement bearings recommendation
This might be a noob question but people keep debating on Misumi vs igus. I have to replace my rods and bearing because one ceased up and scratches my rod (same reason why I had to replace my ex girlfriend). From what I gather from a day of research is the Misumi has a better tolerance and Igus is quiet. My question is, does the looser tolerance have any affect on print quality? I haven't found any mention of it anywhere.
Re: Replacement bearings recommendation
From what I gather from a day of research is the Misumi has a better tolerance and Igus is quiet. My question is, does the looser tolerance have any affect on print quality? I haven't found any mention of it anywhere.
In theory the looser tolerance can introduce lateral movement which could show in the print quality. I changed one of my MK2's from stock to Igus only to reduce noise, which it did. The quality of prints between the 2 remain the same.
Re: Replacement bearings recommendation
In theory the looser tolerance can introduce lateral movement which could show in the print quality. I changed one of my MK2's from stock to Igus only to reduce noise, which it did. The quality of prints between the 2 remain the same.
What you are saying falls in line with my experience. I received a sample igus bearing from igus the other day and they seem to have the same amount of play as the stock bearing. Assuming tolerance is the big part affecting print quality, igus should be the same as the stock bearings but with less noise. My question for the Misumi people out there, does the tighter tolerance of the Misumis with matching rods actually have a noticeable improvement in print quality.
Re: Replacement bearings recommendation
Hey david.s30 I have a few questions. What/how did you mount the bearings on the Y Carriage? The zip ties or with one of the bearing holders?
I have had my MK2 since the end of September and have printed close to 1000 hrs on it and I seem to be in need of new bearings. The printer is making a decent amount of rattle noise and there is definitely some slop/wiggle in the Y carriage.
Also, did you have any issues with the bearings fitting properly into the X or Z parts?
I am thinking I may do the exact same order as you. Which brings me to my other question - did you get 12 bearings just so you could have a couple extra on hand?
Thanks!
Bryan
Re: Replacement bearings recommendation
Sorry for not responding sooner. I haven't had any issues with the bearings or rods based on the parts I ordered. I posted my exact order below for anyone to use. Sadly I don't have a comparison of the rods and bearings for noise, but I haven't had any issues with my install. Z height, but that was unrelated and solved easily. I think the bearings were a good purchase, the sound is fine in my opinion how smooth the bearings glide is very smooth.
I'm no expert but I would check your ties and ensure that they are secure. Check step 12 of the online manual, make sure the rods are correctly installed per the video
http://manual.prusa3d.com/Guide/2.+Y-axis+assembly/104#s5455
Also to another issue I have found is to make sure the bearings are lined up and not off center from each other.
___________------------- - incorrect bearing alignment
__________ __________ - correct bearing alignment
OK, so silly drawing above but the actual bearings inside need to align, this correction cu out some noise for me.
Wiggle seems like it could also be from a misalignment of the X carriage. If you don't have a set, get a set of calipers and measure, measure, measure everything till its all square. I essentially rebuilt my machine after I picked up a set of calipers. They are golden.
I currently am using the zip ties. I just purchased some orange ABS and am going to try and print some of the bearing holders that have been provided by Prusa. I also think I am going to upgrade to the MK2S as the little U bolt seems like a better design. I ordered extra bearings so I can replace them without having to order and wait.
001 [Item Status]:Processed
[MISUMI Part No.]:LMU8
[Brand Name]:MISUMI
[Product Name]:Linear Bushings
[Quantity]:12
002 [Item Status]:Processed
[MISUMI Part No.]:SFJ8-320
[Brand Name]:MISUMI
[Product Name]:LINEAR SHAFT
[Quantity]:2
003 [Item Status]:Processed
[MISUMI Part No.]:SFJ8-370
[Brand Name]:MISUMI
[Product Name]:LINEAR SHAFT
[Quantity]:2
004 [Item Status]:Processed
[MISUMI Part No.]:SFJ8-330
[Brand Name]:MISUMI
[Product Name]:LINEAR SHAFT
[Quantity]:2
A Misumi bearing engineer recommended this is the grease to get for the LMU8 bearings.
https://www.motionindustries.com/productDetail.jsp?sku=03760972
Some guides, etc...May be worth a print
http://www.thingiverse.com/thing:1846705
http://www.thingiverse.com/thing:1848700
http://www.thingiverse.com/thing:1819779
Re: Replacement bearings recommendation
Hi David. You linked to a thingyverse page instead of some grease. 🙂
Re: Replacement bearings recommendation
Thanks for the reply! I ended up doing the exact same order and it will arrive tomorrow so I should be able to do my bearing/rod upgrade this weekend!
I was very careful during the build, and have checked a couple times since, so I am pretty sure everything is square and set up properly. I think the slop/noise from the Y carriage is a direct result, as some have mentioned, of the zip ties stretching/weakening over time due to the many hours of prints. Also they will stretch over time due to removing items from the bed that have adhered really well - there just isn't a good way for the bed to not get torqued a little when removing well adhered items. This has obviously been proven to be a flaw in the design since Prusa is now using those U-Bolts instead of zip ties in that area.
Now I just need to decide which Y carriage bearing holders to print, I wont do the install until I get those done - definitely not using the zip ties in that spot again.
Thanks!
Bryan
Re: Replacement bearings recommendation
Hi David. You linked to a thingyverse page instead of some grease. 🙂
I fixed the link in my original post.
bryan.r that actually makes very logical sense. Heat from the bead could also expand, retract the zipties. I know I am looking forward to the us bolts. I just ordered some orange ABS and plan on doing some mods to the machine if I can. I'm just learning ABS as I was using the PLA that came with the machine. My 3D benchy came out decent, but not nearly as clean as my PLA. Good luck to your build, Id love to hear the difference in the original bearings, rods, slop vs the Misumi.
Re: Replacement bearings recommendation
I will definitely post again when I finish installing and let you know which bearing holder I went with and the difference in the noise/vibration symptoms.
Re: Replacement bearings recommendation
Guys,
It's hard to source Misumi bearings for shipping to Australia so I am looking for alternatives.
Has anyone tried the VXB bearings?
On the basis of their price I would assume they represent higher quality, but would appreciate hearing form those who have purchased them.
Re: Replacement bearings recommendation
Well, it took a while to get back on here and post due to work, etc.. - but for anyone who still cares, I finished installing my Misumi bearings and rods. The machine is now definitely quieter than it was with the stock pieces, not silent by any means, but noticeably quieter.
Not being a mechanical engineering expert - just visual comparison of the stock and Misumi bearings seem to be very similar. The difference on the rods was very noticeable though - the surface of the Misumi rods compared to the stock was definitely far more polished/machined.
For the bearing attachment to the Y carriage I first printed and tried to use these, https://www.thingiverse.com/thing:1848700 , but as soon as I would begin screwing the M3 bolt in they would start to have a slight crack/separation running along the layers due to the orientation they must print. The holders print so that the layers run parallel to how the bolt runs. Maybe it was my print settings and/or the filament I used, but I did not feel confident in using these and did not want to be taking it apart again anytime soon. So I went with a much more secure method that I had to fabricate. I used metal pipe straps exactly like the ones in the picture. It was a bit of a pain because there was a lot of trial and error and detail work but it is worth it knowing those Y carriage bearings will not be wiggling around! Which by the way, the zip ties had definitely loosened up/stretched and were allowing the bearings to have movement. I would flatten out each of the metal straps and then cut them off approx where the red lines are and then drill new holes where the green is to line up with the holes in the carriage. I also had to polish/clean them up on the grinding wheel to get rid of any burs, sharp edges, etc.
In the second image(the crude drawing 🙂 ) I show what this looks like on the carriage with the black being the carriage and bolts, the green being the bearing and the red being the metal strap. This holds them VERY securely. It took a little back and forth tweaking to get the clearance exactly right with the bolt head and/or nuts so that it cleared everything properly but i think it was worth it. Sorry, I do not have a photo with me to post of the finished attachment piece but I'm sure you get the idea. I used M3-0.5 x 22mm bolts and had to do a little grinding on the end of the bolt to make sure everything had plenty of clearance.
Re: Replacement bearings recommendation
Hello,
I am reporting on my Prusa i2 MK2S build using replacement Misumi rods and bearings. Everything went smoothly. The assembly took me several days, mostly because I was (overly) paranoid about right angles. I measured and remeasured everything after each step using Mitutoyo digital calipers or machinist 1-2-3 steel blocks. The printer has been printing since last weekend, and every print is amazing (I have printed only PLA so far). I expected the printer to kind of work, but did not expect this level of quality. The Misumi materials I used are as follows:
Rods (8 mm outer diameter, 52100 bearing steel, induction hardened, g6 tolerance)
SFJ8-320 (2x)
SFJ8-330 (2x)
SFJ8-370 (2x)
Bearings (8 mm inner diameter, no seal, G6 tolerance):
LMU-N8 (10x)
I have not used the stock bearings and rods at all, so cannot comment on how much quieter, if at all, my printer is. Apparently, the "S" version of the MK2 comes with better bearings and rods. However, in all fairness, I still get vibrations of the bed from time to time. I am reasonably sure that they are caused by the fact that the bed is supported by only three bearings that are close to each other and each of which is relatively short. I am planning to modify the entire printer by embedding it in the Rebelix frame and replacing the single Misumi bearings with their double variants, LMUW-N8 (there is a thread about it in the forum). The double bearing is 45 mm long. Exactly when I will do that remains to be seen. The printer is working fine, so I am hesitant to touch it.
Ales
Re: Replacement bearings recommendation
Hi guys,
I finally got around to using my MK2S upgrade kit.
However, I used RJZM bearings(drylin the encased ones) for my Y and X axis(used mofified carriage).
I've had issues with the U-bolts: I think I either over or under- tightened them; they are not really made for this larger bearings so it was a tighter fit anyway. Also, since the bearings have a lower tolerance I think than the default ones, I realized my rods weren't that parallel - like 1mm or half a mm off, so I re-adjusted them and they slide better now.
I still get some vibration in my heatbed on fast movements... not sure if it can be avoided.
What I wonder is if it would be better to use the printed bearings holders for the Y-carriage instead of the u-bolts.
Has anyone else gone this path: U-bolts + igus bearings?
Thank you!
Re: Replacement bearings recommendation
I just got my printer kit and wished I would have started with one of the 2 other bearing solutions. I used calipers to put everything together very precisely but I have a bad bearing. Few days of printing and I have a decent grove in one of the rods and a noticeable slip in my prints when the bed is in a certain position. Sounds like this is fairly rare, but at the same time for the cost of the kit and the cost of the bearings...why are they not shipping with a decent solution.
Anyway a $5 part is now going to take me a long time to fix. Takes away from the kid at Christmas feel of getting my first printer.
So if you don't have your printer yet mk2 buy some barings and trust your gut when you test feed them on the rails.
Re: Replacement bearings recommendation
Just fitted some RJ4JP-01-08 igus bearings to my mk2s and now circles come out oval. Any ideas why? Belts and pulleys seems tight.
Re: Replacement bearings recommendation
I've remixed the MK2S x-carriage so that the RJ4JP bushings fit better - this should avoid any slop and may help fix that:
Re: Replacement bearings recommendation
Just fitted some RJ4JP-01-08 igus bearings to my mk2s and now circles come out oval. Any ideas why? Belts and pulleys seems tight.
Igus bearings are less forgiving than the metal bearings, Y-axis rods must be perfectly parallel and the bearing cannot be over-tightened. But, if they are installed properly, they make the printer very quiet.
Re: Replacement bearings recommendation
I've remixed the MK2S x-carriage so that the RJ4JP bushings fit better - this should avoid any slop and may help fix that:
https://www.thingiverse.com/thing:2421714
Thanks, currently printing these https://www.thingiverse.com/thing:1846705 if I still get issues, i'll give yours a go 🙂