Loosening screws - what's the best torque to apply?
Hi,
I've upgraded my MK3+ to an MK4. During the first service after 200h, I figured out, that a lot of screws needed tightening. For my MK3 Kit I've bought a torque wrench and applied 0,8 to 1,1 Nm. On the MK4 conversion I switched to hand tightening, after the Y-Axis-Motorholder made some cracking noise (it is still okay) on installation.
After >100h of print, I've checked again: loose screws. Is this okay or should I apply more pressure? How is this handled by Prusa in the factory to keep the same quality?
Thanks in advance
Dirk
PS.:
Unfortunately I tightened the Z-Axis Motor screws, although they were "calibrated", but that's another story 🙂
RE: Loosening screws - what's the best torque to apply?
I think that it would be nice to have a recommended torque for each screw too…
RE: Loosening screws - what's the best torque to apply?
I guess the screws getting loose because of vibrations.
Probably a screw threadlocker would be helpful.
e.g. loctite screw thread locker.
Of course only low/medium strength, so screws can be loosened when necessary.
RE: Loosening screws - what's the best torque to apply?
In my point of view "glueing" is not a solution. Is @prusa also using locktite for its factory made printers? I think, they would put a tube of locktite into the kit 😉
RE: Loosening screws - what's the best torque to apply?
i asked same question to prusa:
Answer: There is no recomended torque the say finger tight so its relative 😎
RE: Loosening screws - what's the best torque to apply?
In the late 60's a racing friend owned a small engine shop. When I asked him what the point gap should be on a Briggs & Stratton engine he replied: "A thin dime or two nickels".
Apparently just not that critical.
RE: Loosening screws - what's the best torque to apply?
I have found the Y axis mounts need to be checked every few months. The Y axis rods and the Belt holders are the ones that have loosened on me. The frame, X and Z I don't find bolts loosening. I don't recommend loctite or similar. I think the heating/cooling cycles are part of the problem. The plastic itself may be compressing. The Y axis mounts are relatively small compared to X and Z.
If I had to print the parts over, I would change the Y axis part profile passes to 4 and increase the infil to make them stiffer around the bolts. The non-adjustable end of the belt holder is the bump stop for Y home. When the Y belt mount loosens, Y axis home setitng takes many bumps or fails. I use PETG.
RE:
はじめまして
私も組立時の締め付けトルクに興味と不安を持っています。
私がPrusa 3D chの動画（ ）を見たところ、いくつかの工程でトルク管理されているように思いました。
※トルク管理されてない（手締め）工程もありました。
締め付けトルクが重要となりそうな工程（フレームの組み立て）でのカットが見当たらなかった。
そのため、Herr Lehmannさんの質問に対して、厳密に答えることができていません。
何かの手がかりになれば幸いです。
-makita(Drilled Driver) DF012D
DF012D Manual
nice to meet you
I am also interested and concerned about the tightening torque during assembly.
When I watched the Prusa 3D ch video (), I thought that torque was controlled in several processes.
*There was also a process where torque was not controlled (manual tightening).
I could not find any cuts in the process where tightening torque is likely to be important (frame assembly).
Therefore, we are unable to provide a precise answer to Herr Lehmann's question.
I hope this will be of some help.
-Wera(Driver)
PS
私は英語を正しく理解できないため、日本語での投稿をしました。ご理解ください。
RE: Loosening screws - what's the best torque to apply?
Yeah we are finding that bolts on our factory assembled MK4 are loosening quite regularly. Not sure if they were done properly in factory (our nozzle actually dropped out on the 4th print or so ruining one side of the textured sheet by being dragged around and a bolt holding the electronics box to the inside enclosure had completely stripped the female threads. We can tap a bigger screw but sheesh). Tightening x-axis bolts definitely helped lessen the homing problems we had but so many things were loose we haven't been able to get it tuned to make regular decent prints. Prusa support claimed to not know what we meant by "Torque Specifications" so not holding our breath we will see any help there.
Hoping that checking in on forums occasionally and getting some dedicated time for troubleshooting will help us get our MK4 up to production standards for our print farm. Our MK3s's have been absolute workhorses. We were expecting a drop-in machine that would be up and making production parts in days. Nope.
