High precision composite mould design, Composites Innovation Centre : design report

Abstract

The purpose of this project is to design a high precision composite panel moulding system to improve the manufacturing process currently used by Composites Innovation Centre. The current method uses two flat aluminum plates sealed by disposable tacky tape to house the reinforcement fibre. The plates are adjusted to the desired height by means of set screws and feeler gauges. Resin is infused into the fibres by suction through a vacuum port, and left to cure. Problems associated with the current design include repeatability, time of set up, consumable cost, low fibre volume fractions and lack of heating ability. This project aims to design an improved moulding system by addressing the height adjustment, sealing, and heating systems. The goal is to make the process as automated as possible to eliminate variability between users. High accuracy is achieved by incorporating feedback control to automatically adjust the mould to a specified position using a graphical interface. A mechanical screw jack actuator system is capable of providing large closing force, allowing higher fibre volume fractions to be produced. Electric strip heaters and insulation heat the specimen uniformly without interfering with other systems. Finally, a custom reciprocating seal effectively closes the mould cavity while allowing for adjustment over the range of anticipated panel thicknesses. Analysis is conducted using both finite element techniques and hand calculations for heat transfer, plate deflection, and stresses to ensure that these values fall within an acceptable range. A break-even analysis based on possible manufacturing times was conducted and the mould is expected to pay for itself after producing between 204 and 507 panels (one and two hour manufacturing times respectively). Recommendations for further research are to build a prototype to verify sealing system and expected accuracy, and to conduct time studies to find an exact break-even point.