Rotational Molding is a highly versatile process of plastic molding that allows the development and manufacture of products in small and medium scale at very low cost.
The rotational molding process is ideal for producing large hollow parts and parts with reduced dimensional when the configuration does not allow its production through other processes.
Production rates are relatively low, because production is slow, compared to the other processes.
In the rotational molding process, the thermoplastic material is inserted into the mold cavity in the form of powder, in adequate quantities to meet the thickness requirements of the product.
The mold, which keeps spinning, distributes the material in early merger on its walls, with the effect of centrifugal force, forming a film. After a certain period, the mold is removed from the oven and cooled for maintaining the desired shape of the part, the product is subsequently removed from the mold, often manually.
The injection process is a plastic processing method, which essentially consists in softening the material in a heated cylinder and a subsequent high pressure injection to the interior of a cooled mold, where the cold material turns into the final shape of the mold cavity. The molded product is then expelled from the mold by the extractor pins, compressed air, starter plate or other auxiliary equipment. The production unit for the injection process consists of the following components:
The blowing process is to laminate the plastic compound with the help of a plasticising cylinder equipped with electrical resistors and a thread.
The overall blowing process is used to obtain hollow parts by insufflation (or filling) of air inside the mold to allow the expansion of the plastic mass until obtaining the desired shape. The production unit for blowing process consists of the following components:
The first step of the process involves forming a molten thermoplastic material hose, called parison. This is placed within the blow mold, which is closed by compressing the parison then is blown with air pressure against the mold walls getting the shape of the cavity, the It is cooled and extracted after the cooling stage. In most cases, the product needs to undergo a subsequent finishing process, for example, grinding, drilling, stamping, labeling, etc.