Optimization of the diaphragm forming process with regard to product quality and cost

The diaphragm forming process used for the cost efficient production of thermoplastic composite components has been experimentally investigated. The process has been optimized with regard to product quality and cost. For the process optimization a new generic concept is introduced. The proposed concept involves quality and cost sensitivity analyses by considering the process parameters as variables. For deriving relations between process parameter variation and component quality features, as well as between process parameter variation and component costs, an extensive experimental parametric study was made. For the investigation, the thermoplastic composite APC-2/AS4 was used. The manufactured parts were different, aircraft structure like, simple shapes. Cost estimation relationships were established by using the activity based cost concept. Using the derived empirical relations for the quality and cost sensitivity analyses, the developed process optimization concept could be implemented. The investigation presented the need for the evolution of the diaphragm forming technique into a new ‘cold’ diaphragm forming technique. To evaluate the ‘new’ technique, a testing facility on experimental (laboratory) scale was devised. Simple shape parts from the thermoplastic Borealis PP/E-glass were manufactured with satisfactory quality. The cost for producing components using the cold diaphragm forming technique was estimated and it was found to be significantly lower compared to the cost for producing the same components using the autoclave or conventional diaphragm forming techniques.