Surface blistering/bulging

Local raised bubbles appear on the product surface after hot pressing. Surface defects directly affect the appearance quality and usability of the product, and are particularly evident in transparent products. This defect affects the appearance quality of the product and reduces the market competitiveness of the product.

(1) Gas removal aspect: residual air or volatiles between layers expanding when heated to form bubbles; gas retention forms internal defects affecting product compactness. (2) Material pretreatment aspect: high moisture content of laminated material vaporizing when heated; moisture vaporizes at high temperature to produce gas or participates in side reactions, causing internal defects in the product. (3) Mold aspect: insufficient mold surface finish or poor maintenance. (4) Process aspect: improper temperature or pressure parameters affecting surface molding quality. (5) Material aspect: resin formulation shrinkage or rheological characteristics affecting surface replication accuracy.

(1) Implementation measures: roll-press layer by layer during layup to discharge air; formulate specific operation plans based on actual production conditions and verify implementation effects. (2) Process enhancement: use vacuum bag pressure to further remove gas; increase vacuum degree and ensure sufficient processing time, and proceed to the next process after confirming that bubbles are completely eliminated. (3) Material selection: fully dry reinforcement materials and resin before use., establish material selection evaluation standards and determine the optimal solution through comparative tests. (4) Preventive measures: establish a sound process control standard and quality inspection system, and regularly review process data for continuous optimization.

Surface defects are the result of the combined action of mold condition, process parameters, and material formulation; each factor must be systematically investigated and targeted optimization performed.