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Forums > Engineering Questions and Answers > Mechanical Engineering
Piston seal makes o-ring shaft stick
Last Post 14 Feb 2012 02:16 PM by Niel. 2 Replies.
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ft_surpass
New Member
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Posts:3

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14 Feb 2012 11:49 AM
    I have a 6mm (1/4") shaft that goes through a gland and is sealed by two piston seal o-rings inside the gland. The o-rings and shaft are lubed at assembly but we are finding that after a while (maybe two weeks) when the shaft has been sitting in the same position it gets stuck and is hard to free up.

    Has anyone ever had a problem like this?
    sculley1990
    New Member
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    Posts:3

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    14 Feb 2012 11:56 AM
    Try PTFE o-rings
    Niel
    Basic Member
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    Posts:193

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    14 Feb 2012 02:16 PM
    This is a common issue with rotary seals or really any type of seals.

    Yes, as Sculley noted you can use PTFE O-rings to minimize this issue, but you may be changing one problem for another.

    Couple of things to consider:

    1. Are you over compressing the O-rings?
    2. Is the surface finish on your shaft too good?
    3. Is your O-ring groove dimensioned properly?
    4. Is your O-ring too soft? Consider trying a slightly harder one, this may require a compound change.

    Niel Leon
    engineering.com
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    Forums > Engineering Questions and Answers > Mechanical Engineering