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Asus1357
(@asus1357)
Trusted Member
Assemble torque specs

Yes I know there is a plastic torque tool (with Allen key) but I am not a fan of beam torque settings. I have tried Prusa chats well email and I can get no response. Does anyone know what the actual torque specs are for assembly? No I have not got my XL yet still in limbo like so may others out there.

Posted : 16/10/2023 9:45 pm
Marc and Pintie liked
Pintie
(@pintie)
Trusted Member
RE: Assemble torque specs

i could test what torque the plastic thinggy has.

i would love to use a real torque tool - but i think that is not possible.

the profile ist very small and you can only fit the small key inside.

Posted : 17/10/2023 5:52 am
Asus1357
(@asus1357)
Trusted Member
Topic starter answered:
RE: Assemble torque specs

That would be interesting to know what you get for a reading.
Well since I do not have my unit yet (so not sure of space permitted for assembly then the plastic toll setup makes more sense.
thanks for that response and as well thanks for the anticapted result you get.

Posted : 17/10/2023 1:35 pm
Pintie
(@pintie)
Trusted Member
RE:

so mine has 3,5 Nm

 

no idea how much this is in freedom units

Posted : 18/10/2023 5:28 pm
Marc liked
Asus1357
(@asus1357)
Trusted Member
Topic starter answered:
RE: Assemble torque specs

ok that is great, thanks for the info!

Posted : 18/10/2023 6:02 pm
xenon
(@xenon)
Trusted Member
RE: Assemble torque specs

if the plastics piece is designed to show 3,5Nm, better still be careful.

during assembly the torque felt almost too high, like it was just about to pull the threads out of the metal plates.

check that the extrusion end plates are seated correctly in the slots (rock them back and forth under screw tension to help seat them) and tighten them reasonably. there is a noticable increase in torque when everything is seated correctly and tightened.

Posted : 21/10/2023 11:53 pm
Pintie liked
Asus1357
(@asus1357)
Trusted Member
Topic starter answered:
RE: Assemble torque specs

Thank you for that bit of good info. I will pay great heed to that detail when my XL gets here (this year?)

Posted : 22/10/2023 2:18 am
State Space Systems
(@state-space-systems)
Member
RE: Assemble torque specs

The plastic thingy scale is a PoS. Good concept but poor implementation. The diameter of the scale's neck is too large. When you are tightening the socket head M4 and get too close to the edge of the channel, the neck makes contact with the channel and from that point on, you're measuring the force exerted on the channel and not the bolt. Secondly, with the large neck diameter, the amount of rotation is limited and if not careful, you may not get the allen wrench sufficiently deep into the head for the next rotation and strip out the top of the head. Cheap bolts. I made a trip to the local hardware store and bought (16) M4-12 socket head cap screws - the hardened ones where you'll round off the allen wrench before you round out the hex socket. Made assembly moocho easier and able to get a wrench deep into the socket for each turn. Rather than being so PRUSA and printing their own scale ineptly, they would have been better off going out and  buying a stamped version that resolves many of the issues that I pointed out. When PRUSA builds their printers in-house, they most likely use a torque wrench and do not have the issues as us who purchased the semi-built kits. For the price PRUSA is selling the XL for, they could have spent a few extra dineros for better bolts and torque scale

Just another case of a wanna-be mechanical engineer, or a mechanical engineer, who has no concept of being on the assembly line and PRUSA lacking Q/A to look at assembly problems/procedures and correct them to improve yields. I experienced quite a few assembly issues when assembling my XL that makes me wonder about PRUSA's Q/A or lack of Q/A due to pushing too many out the door while ramping up production with a new crew of workers.

The classic "shake me head twice" faux-pas that I experienced was where they cross threaded a bolt into a self-locking nut. The nut is "supposedly" held in place via one of their printed PETG parts. They most likely (???) use a low torque screw driver for the subassembly manufacturing but the torque was sufficient to round out the hex well. The assembler knew that the nut was turning in the printed piece but rather than pulling it out as a defect, they continued the assembly and left the loose bolt intact hoping nobody would catch their mistake before it went out the door. 

And then we can't forget about the fan test failing unless the bottom shroud is reoved ...

Posted : 20/01/2024 6:33 am
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