This processing method of the material to be crushed into powder, making it melt in the heat cycle and flow. Rotational molding uses two types of PE: General and crosslinkable class. General MDPE/HDPE normal density ranges from 0.935 to 0.945g/CC, with narrow MWD to make products with high impact resistance and minimize warping, the melt index range is 3-8. Higher MI grades are usually not applicable, because they do not have a rotational molding products want to impact and resistance to environmental stress cracking.