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Plastic ring: ID vs. temperature

Plastic ring: ID vs. temperature

Plastic ring: ID vs. temperature

(OP)
I have a plastic ring with a certain ID value at room temperature.
How can I estimate ID at -65 deg C? at 125 deg C?
Do I need to run FEA, or calculations, please?
Thanks.

RE: Plastic ring: ID vs. temperature

You need the co-efficients of thermal expansion over the temperature range involved, then do the very simple mathematics.

The co-efficient of thermal expansion will change over that temperature range. If the currently undisclosed plastic is fibre reinforced, the co-efficient of thermal expansion will vary considerably according to direction of flow when moulded.

Regards
Pat
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RE: Plastic ring: ID vs. temperature

(OP)
Patprimer,

Thank you for explanation.
The plastic is ULTEM 1000, and I was lucky to get a single value of CTE.
I am currently using a simple formula, assuming it expands in both directions along the radius.
I wonder whether there are better ways to estimate ID.  

RE: Plastic ring: ID vs. temperature

Yes, it would be better to use a temperature-varying CTE.
 

RE: Plastic ring: ID vs. temperature

The CTE will vary significantly over that temperature range.

The biggest changes will be as it passes through second order transition points such as GTT.

I do not personally have data on Ultem 1000. Ask Sabic for more detailed data.

Regards
Pat
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RE: Plastic ring: ID vs. temperature

(OP)
Patprimer,
Sorry, I dont know how to get to Sabic.
Thank you.

RE: Plastic ring: ID vs. temperature

(OP)
Sabic did return "0" to ULTEM 1000...


 

RE: Plastic ring: ID vs. temperature

http://www.matweb.com/search/datasheet.aspx?matguid=578c0713b95d4db4a8d8c0c53a872ffb&ckck=1

This gives along and across the flow over a fairly wide temperature range, but not so wide as you require.

YOU will need to contact Sabic directly if you hope to get more detailed information

Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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RE: Plastic ring: ID vs. temperature

(OP)
To TVP:

Thank you for this link!

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