Effect of material and shape of compaction roller on the voids and compaction uniformity in fiber placement process

Automated fiber placement(AFP) has been used to form the large aircraft composites structure in recent years. To ensure the consistency of process in AFP, the compaction roller should be flexible to adapt to the model surface with big curvature and also press the placing prepreg uniformly. In this paper, thin film pressure sensor and ultrasonic microscope are used to measure the pressure uniformity and void distribution of compaction rollers with different elasticity modulus. Compaction roller made with high elasticity modulus material exhibited good pressure uniformity and also reduced the void content. Compared with the polythene roller, the pressure uniformity of the silastic roller is improved by 50% to 60%, and the void content is decreased by 92.1%. Based on the fact that the voids distributed mainly on both sides of the prepreg and the pressure was much smaller on both sides of the roller than that in the middle area of the roller, the shape of two sides of the compaction roller is optimized. The best dip angle of the side plane calculated by ANSYS Workbench module is 20°, the pressure uniformity is improved by 42.9%, and the void content is decreased by 51.6% further.