Asymmetric warpage in length and width directions of laminates

The warpage direction or degree of the board along the length and width directions is inconsistent. Deformation usually gradually intensifies after demolding, especially in asymmetric structures or parts with large wall thickness differences.

(1) Shrinkage control aspect: different fiber laying directions in length and width directions causing anisotropic shrinkage; uneven volume shrinkage causes internal stress and dimensional deviation. (2) Process aspect: uneven cooling causing shrinkage differences in various regions producing thermal stress. (3) Design aspect: asymmetric structure or uneven wall thickness distribution causing anisotropic shrinkage. (4) Material aspect: differences in molecular chain orientation or fiber alignment direction causing different shrinkage in each direction.

(1) Implementation measures: strictly lay fiber directions in an orthogonal symmetric manner; formulate specific operation plans based on actual production conditions and verify implementation effects. (2) Formulation optimization: add 0°/90° balancing layers when necessary., determine the optimal addition amount through small-batch tests, and verify the impact on the comprehensive performance of the product. (3) Design optimization: use symmetric balanced structural design, maintaining uniform wall thickness transition. (4) Post-treatment: cool the product in a setting jig after demolding, or perform annealing treatment to eliminate internal stress. (5) Preventive measures: perform shrinkage and warpage simulation analysis during the product design stage to optimize structure and process plans in advance.

Deformation problems originate from internal stress caused by uneven shrinkage or heating in various parts of the product, and need to be systematically solved from three aspects: structural design, process parameters, and post-treatment.