Modeling and control of an injection pultrusion process

Injection Pultrusion (IP) is a novel process that combines the best features of traditional Resin Transfer Molding (RTM) and wet bath pultrusion for manufacturing polymer composites. Few researchers have dealt with the quality control aspects of this process which is extremely crucial to the plant economics. The main contribution of this paper is the study of the IP process from the point of view of product quality control while maximizing production rates. A mathematical model that includes resin flow and cure, and heat transfer in the part and the die is used to determine sensitivity of the quality variables to important processing variables and parameters. Similarities and differences with traditional pultrusion process are pointed out. Control-relevant features of the process are identified and the requirements necessary for a control system are presented. A cascaded control strategy which uses an on-line process model is proposed.