Squeaky Plastic Threads

[hbarea]

Some times plastics threads make a squeaking sound when unthreaded. If the material can not be changed for the application, can this problem be addressed with a different thread design (pitch to diameter ratio, thread section profile, etc…)?

 

[patprimmer]

Maybe some slip additive to the cap might help without blowing costs.

Some polymers, like styrene, are inherently squeaky.

Thread design will help I am sure, but will also effect other properties, like tendency to work loose.

There are several variables that will impact on this and other properties, like pitch angle, thread profile including side angle of the profile and the clearance at the tips of the thread, and whether or not the male and female threads exactly match or have slightly different profiles.

I have no idea of details in the above regard, other than the peaks of the thread profile should be cut back, but the bottom of the valleys should be retained to give clearance on the peaks.

I am sure when you look at the vectors resulting from the female tightening on the male component, and think about how it will distort, conform and relate as tension increases and decreases, you will think of improvements.

If you wish to discuss the interactions of various plastic compounds in each component and how they interact, I can discuss that in some detail if you choose to disclose details of materials and applications.

Regards

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[MikeHalloran]

As Pat said, more information about the specific problem might net you better answers.

That said, thinning (and weakening) either threaded member might help, as might stiffening the surfaces that are radiating the noise.



Mike Halloran
Pembroke Pines, FL, USA