What is the impact of mold release agent buildup on surfaces?

Buildup of release agents, the material being molded, or byproducts and residues generated by chemical reactions that take place within the mold cavity (in situations where the compound is chemically being changed along the molding process) negatively affect molding performance in terms of heat transfer, part dimensional properties, cosmetic appearance and process efficiency. Mold cavity fouling needs to be regularly removed mechanically or chemically to ensure part quality. Every time the mold needs to be cleaned on-site or otherwise maintained, productivity is lost.

Build up issues can be created by two primary sources:

  • Excess of release agent present on the mold. This may be the result of a poor choice of release agent for the specific application (e.g. not compatible with the process temperature) or over application of the release agent onto the mold.
  • Lack of release barrier causing build-up of the material being molded or byproducts and residues generated during the molding process. In this case, the choice of release agent may not be adequate for the process conditions (not suitable for the process temperature, poor film formation, etc.). This may also be caused by application deficiencies (not enough release agent film present on the mold) or lack of physical and/ or chemical resistance of the release agent to the material which then penetrates the release agent film and physically or chemically adheres to the mold.