×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Help with plastic selection

Help with plastic selection

Help with plastic selection

(OP)
I apologize if this isnt the correct plastic forum, but it was the closet I could find...

I'm in need of a plastic recommendation for a design. For all intents and purposes it can be thought of as a wiper for a wire rope. I need:

-High wear/abrasion resistence
-Some degree of natural lubrication
-Good elasticity properities (flexible)
-Impervious to most factory environment chemicals
-Injection moldable

I have no plastics experience, but my initial thoughts were low density PE, TPRs, or polyurethane. Can anyone give me a better recommendation, something more specific or point me in the right direction? Any info is appreciated.

RE: Help with plastic selection

I would suggest nylon. You can get grades filled with oil, moly disulfide or graphite to reduce friction and help wear. Nylon 6 or 6,6 should both work. Try http://www.rtpcompany.com/ as a good place to start. They will have such grades. Also check www.matweb.com for info and links to suppliers. www.specialchem.com might be of use too.

RE: Help with plastic selection

Depending on degree of flexibility and on temperature generated by friction in operation, nylon, polyethylene or polyurethane would be my choices. I think from the very limited info provided, polyurethane might be best.

Nylon will be best if high speed or high pressure generates a lot of heat.

Polyethylene will be cheap and has a greasy surface, but has a very low softening temperature.

Polyurethane has good flexibility and abrasion resistance, but the temperature resistance is not as good as nylon and the lubricity is not as good as PE

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Help with plastic selection

Need to know more about what your usage is and what chemical and enviromental conditions might be. If you need the product to be truly flexible (like rubber) then a TPE like urethane is your best bet. How many of these things do you need to make? Call up a number of potential material suppliers and let them give you their pitches. Some salesman will only try to sell you only their materials but the better ones know when to back off and recommend the right material. Recommending a material that does not work makes you an enemy for life.

RE: Help with plastic selection

Looking for polycarbonate cleaner for automotive headlight lenses, that are turned yellowed Thank You Paul vallee

RE: Help with plastic selection

Paul. Two comments. One is that your issue should be in a new thread. Secondly, yellow polycarbonate suggests the plastic is degraded and cleaner will not help.


There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell

RE: Help with plastic selection

It is normally the scratch resistant coating that yellows. It is quite hard, but can be polished clean with 1000 grit wet  rubbing pads or even Scotchbrite pads.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Help with plastic selection

The lights tend to last a bit over 10 years here before degrading (at least Honda ones do) but the polish cleaning only lasts about a year, as It would seem their UV stabiliser package has been used up.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Help with plastic selection

Aha, there's a coating on them, I should have guessed. Such scratch resistance coatings are often polyurethane. For example pU is coated onto plastic (PVC) flooring to give wear resistance, control gloss and reduce slip. If the coating is yellow you may be able to apply a new coat. This is commonly done in the case of PU on flooring. Water based coatings are available.


There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources