A Method for Cure Process Design of Thick Composite Components Manufactured by Closed Die Technology

During the manufacture of polymer-matrix composite components the cure degree must be uniform to have a good quality of the product. For thick composite components this condition is not often respected in fact the cure degree trend between the core and the external surface is different causing structural and geometrical/dimensional unconformities. In most cases, these problems are caused by a wrong design of cure process in terms of thermal cycle and tooling, therefore the cure cycle must be designed and optimized. The optimization of cure thermal cycle should include several performance criteria for the production system such as the targeted cure degree, the targeted maximum temperature of the part and the duration of the cure cycle as well as the production system limitations such as the maximum allowable heating rate, the maximum allowable cooling rate etc. This work aims to define by thermochemical phenomena a first step toward the definition of a method to optimize the cure degree of a thick composite components by focusing particular attention to the aspects of thermal degradations and residual stress.