Multi-objective optimization of gate location and processing conditions in injection molding using MOEAs: experimental assessment

The definition of the gate location in injection molding is one of the most important factors in achieving dimensionally accuracy of the parts. This paper presents an optimization methodology for addressing this problem based on a Multi-objective Evolutionary Algorithm (MOEA). The algorithm adopted here is named Reduced Pareto Set Genetic Algorithm (RPSGA) and was used to create a balanced filling pattern using weld line characterization. The optimization approach proposed in this paper is an integration of evolutionary algorithms with Computer-Aided Engineering (CAE) software (Autodesk Moldflow Plastics software). The performance of the proposed optimization methodology was illustrated with an example consisting in the injection of a rectangular part with a non-symmetrical hole. The numerical results were experimentally assessed. Physical meaning was obtained which guaranteed a successful process optimization.This work was supported by the Portuguese Fundação para a Ciência e Tecnologia under grant SFRH/BD/28479/2006 and IPC/I3N – Institute for Polymers and Composites, University of Minho.info:eu-repo/semantics/publishedVersio

Operational Theory of Design and Manufacturing

An operational theory of design and manufacturing is developed which formalizes the design problem and addresses some of its major issues. We first formulate the problem in its most general form and then present a single design axiom. The axiom in effect asserts that the optimum design process minimizes the total expected cost of design and manufacturing. Since the cost is a direct function of the solution procedure, our focus is shifted from the product to the solution procedure. The design axiom is analogous to the principle of minimum energy in physics. In this case the energy equivalent is the total cost and the path of minimum energy is the trajectory of the proposed design vector defines the path. The design axiom then states that the optimum design will follow a certain optimum trajectory of minimum expected cost. One of the direct benefits in formulating the problem in operational terms is that a wealth results from systems theory may now be used to derive useful methodologies for the design/manufacturing process. In the present paper the consequences of the axiom are delineated and general principles of design are derived as a direct outcome of the design axiom. The general principles available to the designer can now be defended on a single principle, thus making possible the rational comparison of alternative schemes

Initial Molding Condition Selection Based on Feasible Molding Space.

ABSTRACT NOT AVAILABLE

Priority-First Minimum Cover Approach to Diagnostics with Application to Injection Molding.

A new methodology is being proposed for application to diagnostics in manufacturing problems. The approach adopts a minimum cover approach where we propose that the requirements for priority and consistency as will be later defined are at least as important as minimum-cover. Thus a priority-first minimum set covering model is proposed to deal with some diagnostic problems, particularly related to manufacturing defect diagnostics. This approach is applied to implement a diagnostic system for manufacturing problems in injection molding

Optimization of Injection Molding Operational Conditions

A major goal of the injection molding process is to produce complex parts to a relatively high degree of accuracy. To do this, one must be able to control the warpage that often occurs in injection molded products. We have developed a methodology to minimize product deformation. Pressure and temperature distributions obtained from flow simulation software are used as an indirect measure of the quality of the molded product. Optimization theory is then used to determine the optimal molding conditions to minimize product deformation