×
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

aging plastic parts

aging plastic parts

aging plastic parts

(OP)
I need to run a test on a pump that has 4 hard plastic feet and two soft plastic motor supports. These two parts have the same dimensions, just different materials. The test is to see if the soft motor supports can be replaced with the harder material. The goal is to have fewer parts in stock.
The first step is to see if there is a difference in the noise between the two parts with new out of the box parts.
The second step is to rapidly age the material 3-5 years and to perform the noise test again comparing the two materials.
The only thing I know about the material is that the are listed as white pvc hard and white pvc flex. A black color is added at the mold. I assume that its some form of pvc.
I am trying to contact the vendor to find out excatly what it is as no one here knows.
Can anyone tell me how to age this material. I thought about cooking it in the oven but I don't know what temperature and how long.

RE: aging plastic parts

Accelerated ageing is not a very exact science, and many unknowns can distort the results.

Heat is the obvious way to accelerate degradation. It accelerates oxidation, chain shortening and cross linking.

It can have an annealing effect and effect shrinkage, distortion and frozen in stress.

Heat will accelerate the rate at which rigid PVC goes brown, hard and brittle.

It will also increase the rate of plasticiser migration in flexible PVC.

If the part is subject to load, heat will be quite non linear in its effect on creep.

Heat will not accelerate the effects of fatigue when a part is subject to vibration.

Regards
pat   pprimmer@acay.com.au
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: aging plastic parts

Flexible PVC changes with time and enviromental exposure. It can get harder due to plasticizer evaporation or extraction. The hardness also changes greatly with temperature so the sound dampening changes dramatically with the product use temperature. If the product is currently made from PVC and its performance is acceptable, the specification or expectation must be very broad. Have you tested a current product that is 5 years old for performance acceptability?  If that is ok, then another PVC that is slightly harder that performs acceptable when new, will likely change the same amount as it ages as the current product that starts out with a higher amount of plastizier. If the current product just barely is acceptable after being around 5 years the new higher hardness product will most likely not be successful.

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