Contact US

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!

*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

Good spring indices for polymer springs

Good spring indices for polymer springs

Good spring indices for polymer springs

When designing a metal spring, usually a spring index of between 4-25 is wanted. But I was unable to find a similar range for polymer springs. Can anyone recommend a range?

RE: Good spring indices for polymer springs

Spring index is driven by the method of manufacture. How are you going to manufacture your plastic spring and what kind of tolerances do you need to hold? Consider that metal coil springs are typically wound from drawn metal wire or bar. The winding can be done hot or cold, and the material could be cold or hot drawn. Things like tolerance on wire diameter, level of springback, tool wear, forming temperature will all affect the final dimensions. Think in terms of how this will apply to a polymer.

How will this spring be used? If the spring will be cycled, fatigue is an issue, and calculating fatigue life in a polymeric component is not straight forward. If the spring will be continuously loaded, creep must be considered. The reality is that polymers are a poor choice for a spring, and there must be an unusually compelling reason to to consider this.

Rick Fischer
Principal Engineer
Argonne National Laboratory

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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close