Development of warpage simulation for rotationally moulded parts and the analysis of process parameters

There are multiple factors that contribute to the warpage problems where molten part is distorted during solidification in rotational molding. A novel warpage simulation model is developed accounting for the effect of various process parameters like crystallinity change, temperature-dependent polymer properties, and cooling rate. The polymer material properties were readily not available; they were constructed from literature data with adaptation to the process condition and their significance on simulation results is discussed in detail. A systematic detailed simulation analysis of warpage in box part was done and results were compared with experimental values published in literature. The warpage magnitude under seven different cooling methods are presented. It was found that externally water cooled parts exhibited maximum warpage which is also corroborated by literature data while the parts cooled by water on either sides of the part show reduction in warpage. The warpage simulation results show an agreement with deviation ranging from 1.2% to 69% with experimental values.