A process performance index based on gate-distance and incubation time for the optimization of gate locations in liquid composite molding processes

The success of filling and curing stages in a liquid composite molding (LCM) depends on many variables such as locations of gates and vents, temperature distribution, flow rate, injection pressure, etc. A great challenge to obtain high quality finished parts is to accurately predict flow pattern, and temperature and conversion profiles using simulation for process design optimization. With the predicted process performance measures, the LCM process can be optimized through locating the gates and vents properly. In this study, a process performance index based on gate-distance and incubation time for liquid composite molding processes is defined. This index allows the consideration of both resin flow and curing issues in process design optimization. Another advantage in using this index in process optimization is that the computation involved is very efficient as only two-dimensional calculation is required. For this purpose, we make use of a new and accurate high order discretization technique for the filling flow kinematics-incubation time evolution coupled model, presented in some of our former works. This makes the index very useful in LCM process design optimization, where costly iterative stochastic search algorithms such as genetic algorithms are used. The effectiveness of the approach is illustrated through a number of examples which involve race tracking, areas with different permeabilities, different filling conditions, etc. (C) 2005 Elsevier Ltd. All rights reserved.