Significance of Processing Parameters on the Warpage of Rotationally Molded Parts

Part warpage caused by inappropriate mold design and processing conditions is one of the problems that confound the overall success of rotational molding technology. This report is devoted to investigate the effects of different processing parameter on part warpage. The first part of this report is to optimize the warpage of rotationally molded parts. An L’18 orthogonal array design based on the Taguchi method was conducted to optimize the warpage of rotationally molded thermoplastic parts. The second part of this report is to identify the relative significance of each processing parameter on the warpage of rotationally molded products. Experiments were carried out on a lab-scale rotational molding machine. The polymeric material used was linear low density polyethylene. After molding, the warpage of molded parts was characterized by a profile-meter. For the parameters selected in the main experiments, the cooling condition was found to be the principal parameter affecting the warpage of rotationally molded thermoplastics, while the effect of pigmentation was relatively limited.