Optimisation of injection molding process parameters for improvement in tensile strength using the taguchi experimental design.

Tensile strength is an essential parameter for improving the quality of Injection-molded products. This thesis presents an experimental investigation into the impact of input variables of plastic injection molding process on the ultimate tensile strength of High-Density Polyethylene. Depending on Taguchi quality design concept, a L16 mixed-level array was implemented to evaluate the S/N ratio (dB), analysis of variance (ANOVA) and the 'F' test values for detecting dominant process variables influencing the injection molding performance and product quality. The ultimate tensile strength was improved with the optimum setting of input parameters. The input parameters were Injection Pressure, Melt Temperature, Cooling Time, Mold Temperature, Injection Speed, Holding Time, and Holding Pressure. Here, the room temperature was selected as a noise factor whereas the output response was ultimate tensile strength. Based on the experimental results and through ANOVA and 'F' test values, all the control parameters were observed to be significant, but the room temperature was insignificant (P value .054). Considering these significant parameters, verification of the improvement in the quality characteristics of the product has been made through confirmation test concerning the selected initial parameter setting. [ABSTRACT FROM AUTHOR]