Cost modeling and design for manufacturing guidelines for advanced composite fabrication

Abstract

Experience shows that the majority of costs are committed during the early stages of the development process. Presently, many cost estimation methods are available to the public for metal processing, but there are almost none (excluding proprietary) for advanced composite materials. Therefore, the central objective of this thesis is to provide a comprehensive overview of the costs of common composite production technologies such as Hand Layup, Resin Transfer Molding, Automated Tow Placement, Pultrusion, Forming, and Assembly. The work includes information on investment costs for production equipment and tooling as well as estimation guidelines for labor and material. Designers are presented with Design for Manufacturing guidelines (DFM) explaining how process selection and part design can lead to potential cost saving opportunities. Process based or technical cost models are well suited to quantify manufacturing costs and relate them to part design features, such as size and shape complexity. These physically based scaling principles can be easily adapted to changes in process technology and thereby reducing data requirements. In order to identify all relevant cost drivers, a detailed process plan is compiled for each composite manufacturing method. These processes can include up to 50 process steps and a total of 270 cost equations are used to calculate the cost contribution of each.

(cont.) A number of case studies conducted in concert with our industrial sponsors clearly identifies the best point of each production process and for example help to explain the economic benefits of co-curing versus mechanical assembly. Users can therefore study the economic consequences of design changes in detail and consequently highlight any favorable design/process combinations. To further facilitate the comparison of process performance and to promote the feedback from industry all of the models are available on the Internet at http://web.mit.edu/lmp/www/composites/costmodel/.