SCALING DOWN METHODOLOGY FOR COMPOSITE CAB FRONT PROTOTYPE USING RESIN TRANSFER MOULDING PROCESS

摘要

Most of the industrial composite parts that have large and complex geometry are manufactured by Hand Lay Up (HLU) method. Resin Transfer Moulding (RTM) process is a better substitute, but is not used readily due to the lack of proper manufacturing technology. Development of a proper RTM manufacturing process for a specific application requires a proper mould design. In addition, the difficulty in the tooling design and mould fabrication cost increases with increase in size and complexity of the component. The scale down strategy of full scale product avoids bigger size mould requirements, prototype bulk production for product testing and quality check at the starting phase of product development. Moreover, the mould scale down strategy paves the way to validate the process and the product with less capital input. Hence, there are tremendous beneficiations in scaling down large and complex shapes which represents the full scale product. In this work, we propose a mould scaled down strategy for a large and complex high speed train cab front prototype through RTM process. The mould scale down strategy was developed using isothermal moulding filling simulations based on the mould fill time and mould fill pattern comparisons between full scale and scale down model. From the simulations and actual experiments, it was found that the injection pressure at the full scale model has to be reduced to the times of reciprocal of square of geometrical mould scale down factor to meet the same mould fill time and mould fill pattern, provided the same injection strategy in both the scales. Similar scaled down methodology can be used for developing scaled down prototype other large and complex composite components.