Shrinkage stress causing deformation/microcracks

Microcracks appear in laminated products after demolding and cooling. 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) Process factor: large difference in thermal expansion coefficient between resin and reinforcement material; this factor affects the '2079851475616104453 and final quality of the product. (2) Process speed aspect: cooling rate too fast forming thermal stress; speed parameters affect the synchronization of material flow state and reaction progress. (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) Process control: control cooling rate; establish an online monitoring mechanism, set parameter upper and lower limits and implement alarm management. (2) Material selection: select resin systems matching the thermal expansion coefficient of fibers; establish material selection evaluation standards and determine the optimal solution through comparative tests. (3) Implementation measures: symmetric design of laminates to reduce internal stress., formulate specific operation plans based on actual production conditions and verify implementation effects. (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.