rotational molding, also known as rotomoulding, rotary molding, etc., is a hollow molding method for thermoplastic plastic . the method is, first to add the raw material to the mold, and then the mold continuous rotation along the vertical axis and heat it, the plastic material in the mold under the action of gravity and heat, gradually evenly coated, melt adhesion to the entire surface of cavity, to be the required shape, and then by cooling stereotypes to finish products.
process principle
the basic process of rotational molding is simply , to put the powder or liquid polymer into the mold, while heating, the mold is rotated around the vertical axis, then cooled. at the beginning of the heating phase, if a powdered material is used, a porous layer is first formed on the surface of the mold and then gradually melted with the circulation process to form a homogeneous layer of uniform thickness. if a liquid material is used, coated on the mold surface first, when reached the gel point then stop flow completely. the mold is then transferred to the cooling work area, forced cooling by ventilation or water , and then placed in the work area, where the mold is opened, the finished part is removed, and then the next cycle.
