Compression molding

Compression molding is a method of molding in which a precise quantity of molding compound containing thermosetting or elastomeric resin called a charge is placed in the bottom half of a heated mold cavity, then flows to fill the cavity as the 2 sides of the mold are pressed together. The heat causes the material to polymerize and solidify, after which it can be removed as a solid part. The process typically uses high-strength hydraulic cylinders to push the mold sides together with hundreds of tons of force. Compression molding has lower tooling cost and wastes less material compared to alternatives like injection molding, but it is limited to simpler geometries and has a slower production rate.

Compression molding is well suited to working with fiber reinforced polymers. Reinforcement such as glass, aramid, and carbon fibers can be added to the charge to produce parts with greater stiffness and strength. It is also widely used to produce sandwich structures that incorporate a low-density core such as a honeycomb or polymer foam.

In compression molding there are six important considerations that an engineer should bear in mind:

  • Determining the proper amount of material.
  • Determining the minimum amount of energy required to heat the material.
  • Determining the minimum time required to heat the material.
  • Determining the appropriate heating technique.
  • Predicting the required force, to ensure that shot attains the proper shape.
  • Designing the mold for rapid cooling after the material has been compressed into the mold.
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.