Rotational molding is a single-surface molding process. This means that the mold can only affect the quality of one surface of the molded part. The advantage of rotational molding is that the wall thickness distribution of rotomolded parts can be controller relatively easily by changing the speeds of rotation of the mould about the two perpendicular axes. Its good to specify a minimum wall thickness rather than a nominal wall thickness. As there is very little melt flow in rotational molding, the speeds and speed ration during the rest of the cycle is not so critical.