Reducing Warpage in Injection Moulding Processes using Taguchi Method Approach: ANOVA

Yousef Amer, Mehdi Moayyedian, Zeinab Hajiabolhasani, and Lida Moayyedian


Plastic injection mould, Taguchi method, Analysis of variance, Warpage


Mould making is one important industry involved in our life, since moulded products contribute to more than %70 of components in products. However, there exist common defects in any moulding process particularly in plastic injection moulding such as: warpage, shrinkage, sink marks, and weld lines. In this paper, two distinctive approaches of Taguchi method, to reduce the warpage defect of thin plate Acrylonitrile Butadiene Styrene (ABS), will be implemented in two levels; namely, orthogonal arrays of Taguchi and the Analysis of Variance (ANOVA). In order to improve this process, injection pressure (A), packing time (B) and cooling time(C) were identified as the most effective factors. Also, appropriate parameters settings were determined using Taguchi’s experimental design method. Based on data measurement sensitivity, through trial and error method the optimum alpha rate; 0.8 was chosen. Furthermore, p rate for each parameter (A, B, and C) and their combinations (AB, AC, and BC) were identified. As a result A, B, AB, and AC were significant factors, while C and AC were insignificant. The results obtained from ANOVA approach analysis with respect to those derived from MINITAB illustrate, in former, A and B are the most significant factors which may cause warpage in injection moulding process. Moreover, ANOVA approach in comparison with other approaches like S/N ratio is much more accurate, resulting from the alpha rate, and also the interaction of factors is possible to achieve the higher and the better outcomes.

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