Rigid foam shrinkage after demolding causing peeling from substrate

The insulation layer foam falls off from the substrate. Such defects mostly occur in thick-wall transition areas of the product and at the far end of the gate, gradually appearing during the cooling and setting stage. This problem causes product dimensions to exceed the tolerance range, affecting assembly accuracy and product function.

(1) Shrinkage control aspect: foam shrinkage stress greater than the bonding strength between foam and substrate; uneven volume shrinkage causes internal stress and dimensional deviation. (2) Process factor: poor substrate surface treatment; this factor affects the '2079851475616104453 and final quality of the product. (3) Material aspect: resin system curing volume shrinkage rate too large, lacking effective constraint. (4) Process aspect: curing rate too fast, shrinkage stress has no time to relax and release. (5) Design aspect: large wall thickness differences causing inconsistent shrinkage in various regions.

(1) Operation specification: substrate surface cleaning and roughening treatment; formulate standard operating instructions for cleaning operations and perform inspections before each production. (2) Implementation measures: apply primer adhesion promoter; formulate specific operation plans based on actual production conditions and verify implementation effects. (3) Formulation adjustment: optimize formulation to reduce foam shrinkage rate., adjust gradually and verify the effect, ensuring that other performance indicators of the product are not affected. (4) Preventive measures: establish a shrinkage rate database, preset shrinkage compensation amounts based on product structure and material type, and regularly calibrate mold dimensions.

The core of shrinkage defects lies in the contradiction between material curing volume change and insufficient process compensation, which requires comprehensive control through formulation optimization and process adjustment.