What is rotational molding?
Rotational molding, also known as rotational molding, is a processing method for making hollow seamless products of various sizes and shapes. Traditionally, it is mainly used in thermoplastic materials. In recent years, the rotational molding of thermosetting materials such as crosslinkable polyethylene has also developed rapidly. Since rotomolding does not require higher injection pressures, higher shear rates or precise compound dosers. Therefore, the mold and machine are relatively inexpensive, but also a longer service life. Its main advantages are: the machine's performance / price is relatively high; complex parts do not need to be assembled after the molding; a variety of products and a variety of colors can be formed at the same time; mold cost is low; color and material easy to change; The basic process is very simple, putting powdered or liquid polymer in the mold, heating while rotating around two vertical axes and then cooling. At the beginning of the heating phase, if a powdered material is used, a porous layer is formed on the surface of the mold and then gradually melted as it is circulated to form a homogeneous layer of uniform thickness. If a liquid material is used, it is flowed and coated The mold surface stops flowing completely when the gel point is reached. The mold is then transferred to a cooling zone, cooled by forced ventilation or water jetting and then placed in the work area where the mold is opened and the completed part is removed, followed by the next cycle