Causes of Shrinkage and Deformation in Fiberglass Composites
Shrinkage and deformation are common problems in the fiberglass composite processing industry. What causes this?
Shrinkage occurs through two mechanisms: curing shrinkage and cooling shrinkage.
The first mechanism, curing shrinkage, typically occurs in two stages: curing (before and after demolding) and post-curing (after demolding).
1. Curing shrinkage refers to the volume change of the resin during the curing process. This solidification shrinkage is unavoidable and is best avoided before release from the original mold.
2. After removal from the mold, some solidification occurs, and this additional shrinkage can cause defects on the mold surface. This is often referred to as "post-cure," but the true deformation is due to the additional shrinkage during the post-cure process.
Thus, choosing the right low-shrinkage resin is the most effective way to address these issues.
