The Design and Manufacturing of Prototype Cutting Machine for Prepreg Composite Sheet Preparation

Abstract

This research aims to solve the problems related to manually cutting of composite laminated sheets, commercially known as Prepreg. After manually cutting experiment, two main issues were identified. The first issue is that manual cutting takes a long time because Prepreg sheets cannot be stacked together while cutting. If stacked, it may not be possible to complete the cut in a single attempt, which negatively affects the quality of the cutting edge. Cutting Prepreg sheets across the fiber direction (transverse direction) is more difficult than cutting along the fiber direction (longitudinal direction) because cutting across requires severing all fibers, making it more time-consuming than longitudinal cutting. The second issue is the significant dimensional inaccuracy in manual cutting. This inaccuracy accumulates from the first sheet onward, leading to the greatest errors in the final sheets. In order to resolve these problems, the research team designed three concepts of cutting machine. Three experts were invited to evaluate and score the features of the machines in order to select the most suitable concept. After manufacturing the cutting machine, cutting experiments were conducted. It was found that the time taken for longitudinal and transverse cuts was very similar, as the cutting tool reduces the influence of human effort in the cutting process. The machine could reduce the average cutting time along the fiber direction and across the fiber direction by 26.70% and 42.61%, respectively. The standard deviation of the cutting time was reduced by approximately 31% compared to manual cutting. Additionally, it was found that the size of the Prepreg sheets cut by the machine is more precise than those cut manually.