Rotational molding process, also known as rotational molding and rotational casting molding, is a hollow molding method for thermoplastics. Rotomolding is a versatile process for manufacturing various hollow plastic parts
The rotational molding process uses heating and rotation along two axes to produce a single hollow part. The molten plastic is injected into the rotating mold, and the centrifugal force forces the molten plastic to stick to the inner wall of the mold. The advantages of the rotational molding process are the ability to produce multilayer plastic parts, which can be integrally formed, the thickness can be changed according to requirements, and the production cycle is short. The plastic process has a strong substitute for a variety of traditional processes and its own process advantages. Its low development cost, short production cycle, and strong ability to adapt to market changes, so it is widely used in construction machinery, automobiles, medical, military, home appliances, toys, environmental protection and other fields, especially suitable for the production of large, hollow, seamless plastics Products.
The fine powder is on the outer layer and the coarser powder is on the inside. When heated in this way, the fine powder near the mold melts first to form the outer skin. If the powder is very rough, there will be a gap between the powder and the powder, there will be air in it, and pinholes will be formed after demolding. In addition, the rough powder will trap air in it. Too much air cannot be completely melted during the heating process, and the final manifestation is bubbles in the wall.
One of the most important advantages is that all materials can be made into microbeads, but there are many materials that are difficult to grind into powder, such as polypropylene, nylon, EVA and so on. The dry flow rate of microbeads is lower than that of powder, but the bulk density is higher.
This eliminates the step of grinding powder, reduces costs, and reduces the requirements for machinery and equipment. However, relatively large particles will extend the melting time and relatively reduce efficiency.
