Development of cost estimating tool for thermoplastic composite aerospace parts manufactured by compression moulding process

Abstract

In order to exploit more benefits of the advanced composites materials in different industrial sectors especially aerospace industry and to ensure competitiveness and economic viability, it is important to integrate cost estimation into the design process, right at the start of product development. However, the cost models for estimating composite material parts are almost nonexistent. A multidisciplinary research team comprised of many universities was formed to carry out a project aimed at developing compression moulded processes for thermoplastic composites used to produce structural aerospace parts made by two different compression moulding processes. The first one aimed to make three categories of parts from discontinuous prepreg randomly oriented strands (ROS) whereas the second produces a concave part from unidirectional continuous fibre prepeg sheet (UD). The objective of this thesis was to develop a parametric cost estimation model based on physical laws. From academic and industrial data, different cost equations were integrated in Microsoft Excel spreadsheet for calculating costs elements such as material, labor, energy, tooling, machinery, building costs, and costs of working capital, overheads and then the total cost per part. This research study focuses, on one hand, at estimating the heating energy and the tooling costs for experimental and virtual parts by changing the volume and keeping the same process cycle times. The heating power was determined by simulating numerically the process thermal diagram using finite elements COMSOL software and validated by experimental data. On the other hand, the study aims also at estimating the tooling costs by DFMA software for experimental and virtual moulds by changing the projected area. Then, the heating energy and tooling costs sizing scaling laws were established under linear equations forms limited to the size of platens areas. These linear equations were imputed in Excel program in order to calculate the cost of new parts which have not been made. For ROS parts, it was found that the calculated heating energy costs of the three experimental part forms were different due to different geometries of the heating platens and the moulds used. However, for tooling, the estimated costs were close to the real costs. It was concluded the more complex the mould is the higher the cost. It was also demonstrated that the manufacturing cost of a L-bracket part was higher than that of a flat plate and one T-shape part due to higher process cycle time. For UD parts, the calculated heating energy costs for different part forms do not depend on the volume of the part. For tooling, there was no significant difference between the total estimated costs and the commercial costs for concave mould. It was also found that there was no significant difference between the parts manufacturing costs. From comparisons results between composite thermoplastic parts costs manufactured by compression moulding process and those in composite thermoset manufactured by autoclave process, it was concluded that the compression moulding process is more economic with respect to autoclave process due to long cure cycle and autoclave investment costs.

Date	28 Jun 2016
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Anh Dung Ngô (Supervisor)