Referring from the literal meaning of the rotational molding, it is generally expected to keep rotating while processing. And it is a particular molding which is a molding process for creating many kinds of mostly hollow items, typically of plastic. It is true that it holds a long history dated back to about 1855. Actually, with the advanced technologies and enlarging material fields, especially within these two decades, many improvements have been made to optimize the process and products. plastic rotational molding companies
At first, the proper manufacturing machines are needed as there is a wide range of sizes for them. Generally speaking, they consist of molds, an oven, a cooling chamber and mold spindles. And it should be mentioned that the quality of the products is closely related to the quality of the mole being used. Molds are typically manufactured from stainless steel or aluminum. They are generally used for less complex parts as a result of being less expensive, comparing to the cast molds which are resulting from the need to develop a model prior to casting. As we hoped that the oven is used to heat the part and the cooling chamber is placed to cool the part when it has been done. And the spindles are mounted to rotate and provide a uniform coat of plastic inside each mold. There are some special manufacturing machines such as rock and roll machine, clamshell machine, vertical or up & over rotational machine, shuttle or swing arm machine and carousel machine and so on. Each type is applicable for its own specifications and employed into specified fields.
Then, the material should be suitable for molding. It is common to use polyethylene like cross-linked polyethylene, linear low density polyethylene, and high density polyethylene and other compounds. Aluminum, acrylic and silicon and such kind of materials are also used. What else, some natural materials such as real sands and stone chip, sandstone composite are employed for molding. In terms of various materials and requirements, the products are in a wide range. The general molding process is introduced in the following.
The rotational molding consists of 4 distinct phases. Firstly, a measured quantity of polymer is needed to place into the mold. Then, it is to make the oven working while rotating. It is expected to rotate in different speed rates according to the real status of the polymer. And it is the important procedure as to produce a fine part. Afterward, the cooling chamber comes to affect until the polymer solidifies and can be handled safely by the operator. And the cooling speed should be controlled carefully. Otherwise, the part would not achieve the premeditated results and all the things would have been done in vain. At last, it is the step to remove the finished part. At this moment, it has been totally completed. Thus, the parts can be put into use and start to affect to bring benefits.