Best Plastic for a Split Bush

[ikr]

Please can you give some guidance to a chemical engineer who needs to solve a mechanical engineering problem?

I need to clamp a stainless steel tube in place by using a split plastic bush. A band clamp then compresses a split metal housing around the bush. Can anyone advise an appropriate material for the bush?

The tube to be clamped is about 1" diameter, and the bush about 35mm long. The bush and housing are machined cylindrical, then sawn in half vertically to give a compression gap.

Operating conditions are up to about 50C, with an axial clamping force of about 50kg. The tube won't be repositioned very frequently, so low creep is desirable.

Any suggestions? I have a hunch that glass reinforced PEEK is used in this sort of application, but no real data. Brass is a possibility, but I'd rather not risk scratching the stainless tube.

Thanks

Ian Richards

 

[Cheddarcaveman]

Hi there. Before I finished reading your post I had PEEK ( Polyetheretherketone) material in mind. A full specification for this can be found at:

http://www.azom.com/details.asp?ArticleID=1882

 

[strokersix]

Don't know if you've already solved you problem or not but here is a suggestion: Leave an internal flange on both ends of the housing. This will effectively trap whatever polymer busing you use and prevent it from creeping. You might also do final machining after splitting in order to minimize the saw kerf gap.

 

[CoryPad]

I missed this thread the first time. PEEK and PAI (Torlon) are used frequently for this. You can find suppliers via Google.

Regards,

Cory

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