Design Of Simulation Experiments method for Injection Molding process optimization

Purpose:Many studies demonstrate that DOE, CAE and optimization tools can be very effective in product and process development, however their integration is still under investigation, hampering the applicability of such engineering methods in Industry. This paper presents a Design Of Simulation Experiments (DOSE) method, developed to determine the optimal set of process parameters (factors) for given product requirements (responses).Method:The method is developed performing an original selection and integration of engineering procedures and techniques based on DOE, CAE and multi-objective optimization, chosen according to the following criteria: ease of application, time-saving and use of reduced resources.Result:The developed method consists of two main steps: a first screening of factors based on a fractional DOE is followed by a systematic experimental plan based on the Response Surface Methodology (RSM), in which only key factors are investigated. A regression model is finally developed to describe the responses as functions of key factors and a multi-objective optimization is proposed to obtain optimal responses by tuning the process factors in their variability range. The DOSE method is finally validated on the design of an injection molded housing for a biomedical application. This thin shell component has dimension 45mmx37mmx16mm, wall thickness from 2mm to 0,5mm and is made of polyphenylsulfone (PPSU), a high performance thermoplastic.Discussion & Conclusion:The design method achieves good responses in terms of dimensional and geometrical requirements (e.g. warpage, shrinkage, sink marks), and improves the shell moldability. The DOSE method can be easily adopted in industrial product/process development to define the optimal process parameters for a better final quality of the products.