Product warpage deformation

The product bends or twists after demolding. Warpage deformation has various manifestations: flat products show bowl-shaped or saddle-shaped bending, strip products show bowing or twisting, and box-shaped products show opening dimension changes. The directionality and severity of deformation depend on the distribution pattern of cooling unevenness and the symmetry of molecular orientation. Warpage has hysteresis——it may not be obvious when just out of the mold, and gradually appears after storage for several hours to several days, which brings challenges to production process quality control.

1. Cooling factors: uneven curing shrinkage, uneven cooling, uneven product wall thickness, flow direction orientation causing anisotropy. 2. Runner and gate design factor: In transfer molding, the material needs to enter the cavity through runners and gates; the runner length, cross-sectional shape and gate size directly affect pressure loss, fiber breakage and filling balance, and unreasonable design is the root of many quality problems. 3. Feeding factor: The volume of the feeding chamber, the feeding amount and the preheating state of the material directly determine the transfer pressure and filling effect, and are key variables unique to transfer molding.

1. Process parameter optimization and adjustment: cure uniformly, cool uniformly, optimize the wall thickness design, set gates symmetrically to balance orientation. 2. Systematic troubleshooting method: Troubleshooting of transfer molding problems follows the order of 'runner -> feeding -> parameters -> mold'. First check whether the runners and gates are blocked or worn, then verify the feeding amount and material preheating, then adjust the transfer pressure and speed, and finally check the mold venting and temperature uniformity. 3. Preventive management: Establish standardized process parameter cards and quality control limits for each set of mold/product, and regularly conduct process capability index (CPK) evaluations. For recurring problems, use fishbone diagrams or 5Why analysis to trace the root cause, and solidify the countermeasures as PFMEA control points.

Warpage is the macroscopic bending caused by inconsistent shrinkage of various parts of the product. The solution idea is: achieve uniform cooling of all parts during the cooling stage (cooling water channel optimization), adopt symmetrical layout and isotropic design in structural design (wall thickness and gate position optimization), and reduce shrinkage anisotropy in material selection.