Annoying squeaking sound

[trudels]

Hi guys,

I designed a friction-based blocking system. The system basically consists of a shoulder bolt rubbing in a slotted plastic piece. The plastic is Nylatron GSM, and the shoulder bolt is standard steel.

The system works well, except after a certain amount of cycles, there's a very annoying squeaking sound coming from the friction between the plastic slot and the shoulder bolt. I put Jig-A-Loo on the shoulder bolt and the squeaking disappeared, but only for some time. The problem is that I can't tell the customers to put jig-a-loo in there every time it squeaks! I have to use food-grade grease, but I don't want to cause it would decrease the friction force a lot plus it would gather dust...

I cannot change the plastic and ran out of ideas for stopping this squeaking.

Does anyone of you guys could help me?

Thanks a lot

 

[patprimmer]

I have never known nylon bearings to squeak.

What is a Jig-A-Loo.

Could the nylon simply be drying out. What is the environment.

Ia dust from wear collecting.

Is there a repeated sterilization process that might be degrading the nylon.

Can the friction be controlled by a longer bolt with a spring between the head of the bolt and a big washer bearing on the nylon.



Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

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for site rules

 

[cloa]

http://www.jigaloo.com/us/files/pre...._to_Make_The_World_Run_Smoother_20070424.pdf

Jigaloo is a spray on lubricant.

 

[unclesyd]

Make sure you have the Nylatrom with the highest loading of MoS2.

You may want to try using a dry lubricant like WS2 in lieu of the MoS2. If you have very many to do there is a process where WS@ can be impregnated in to plastic.
You also may want to try Graphite. In the same vain You could also consider Bron Nitride.

 

[Demon3]

Ultra high molecular weight silicone masterbatch is available in nylon too. Perhaps that would help. Suppliers are Dow Corning Multibase and Wacker.

Chris DeArmitt PhD FRSC CChem

 

[msquared48]

I too was thinking graphite, but if you are restricted to a food grade lubricant, graphite is not your answer.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[Demon3]

The UHMW silicone is food approved

Chris DeArmitt PhD FRSC CChem

 

[msquared48]

Then again, there's astroglide... or not.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask