Relationships between Degree of Skill, Dimension Stability, and Mechanical Properties of FRP in Hand Lay-up Fabrication Method

Abstract

Hand lay-up fabrication has been used for forming composite structures since ancient times as it can be performed as long as the mold, skills, and materials are available. On the other hand, the hand lay-up fabrication work itself relies on human skills, which means that the finish differs according to the operator carrying out the work, the quality of the product differs among parts depending on the ease of forming, and that defects such as bubbles tend to occur easily. Hence highly specialized control technique and the tradition of skill are required to ensure the consistent stability of product quality. For this reason, the tradition of molding techniques needs to be carried on as quickly as possible. In this study, the authors thus conducted a motion analysis experiment using hand lay-up fabrication experts as subjects. The experiment, seemingly a new and only attempt in Japan, quantified techniques that are not visibly apparent and considered to be tacit knowledge. The mechanical properties and dimension stability of samples were measured, and their relationships with the motions of experts were also evaluated. It was also suggested that highly specialized control techniques, the appropriate training of nonexperts, and technical tradition are possible