Study of orange peel phenomena in rotational molding

The term "orange peel" describes a surface defect that is characterized by irregular grooves and pitting - much like the topography of the outer skin of an orange. Although similar phenomena have been reported for high-pressure processes such as injection molding, the root causes of orange peel in rotational molding are essentially unknown. The presence of orange peel is undesirable not only for aesthetic reasons, but also for its potential negative effects on the functional properties of the final product. A fundamental study was conducted to determine the root causes of the orange peel in rotational molding. The effects of material properties such as density, rheological, thermal and powder properties, and process parameters were investigated. In addition, comparisons are made between the dry blended and melt blended samples in terms of orange peel development.