What are the advantages and disadvantages of rotational molding technology?

What are the advantages and disadvantages of rotational molding technology?

The advantages and disadvantages of rotomolding technology are as follows:

Advantages
Low mold cost: Rotomolding molds are simple, pressure-free, thin-walled and lightweight, and cost about 1/3 to 1/4 of blow molding and injection molding molds, and the manufacturing cycle is short.
Suitable for large and extra-large parts: During molding, the mold and material are basically not subjected to external forces, and there is no need to use molds and equipment that withstand high pressure. Large and extra-large plastic parts can be easily produced, and the size is theoretically unlimited.
Flexible production of multiple varieties and small batches: The mold is not subject to external forces, is simple and easy to change, and the equipment is highly maneuverable. A rotomolding machine can be installed with molds of different sizes and shapes, and can produce multiple products at the same time.
Convenient color change: Each time the material is added directly to the mold, the product is taken out and the next required material is added to change the color, without wasting raw materials, and there is no need to clean the machine and mold.
Suitable for complex hollow parts: The material is gradually coated and deposited on the inner surface of the mold, and the product can well replicate the fine structure such as the pattern on the mold cavity, and various complex shapes of hollow parts can be formed.
Save raw materials: The wall thickness of the rotomolded products is uniform, and the chamfers are slightly thicker, which can give full play to the material efficiency. There is no waste such as runners and gates during the molding process, and the material utilization rate is high.
Easy to produce multi-layer products: Materials with different melting temperatures can be loaded into the mold for rotomolding, or the outer layer can be molded first and then the inner layer can be added for rotomolding, so as to realize the production of multi-layer products without complex equipment.
Good product performance: Rotomolded products have no joints, no internal stress, are not easy to deform or dent, have good edge strength, can achieve product edge thickness of more than 5 mm, and can also be filled with foaming materials for insulation.
Diverse surface treatments: A variety of surface pattern treatments can be provided, and products of various colors can be produced. They can be treated with UV protection and anti-aging treatment, and can also be used for a variety of stone and wood simulation effects.
Disadvantages
Large energy consumption: In each molding cycle, the mold and mold frame must repeatedly undergo high and low temperature alternations, and the energy loss is large. Although the jacketed rotomolding machine can reduce the energy consumption of the mold frame, the mold still needs to be repeatedly subjected to cold and heat.
Long molding cycle: The material gradually melts and adheres to the surface of the mold cavity by contact with heat. The heating time is long, usually more than 10 minutes, sometimes up to more than 20 minutes, and the entire rotational molding cycle is long.
High labor intensity: Loading, demoulding and other processes are not easy to mechanize and automate, usually manual operation, and the labor intensity is greater than that of blow molding, injection molding and other molding processes.
Poor product size accuracy: The product size is restricted by many factors such as plastic type, cooling speed, type and amount of release agent, and the size accuracy is difficult to control. It is only suitable for products with no special requirements for size accuracy.
Limited product types: It is usually only suitable for the production of hollow parts or shell parts. It is difficult to make solid parts, and it is impossible to prepare parts with large differences in wall thickness, sudden changes in wall thickness and flat sides.
Limited raw material selection: Roto-molding requires specially designed materials, and has requirements for the fluidity and melt index of raw materials. The types of raw materials that can be selected are relatively limited, and the raw materials need to be ground into powder or kept in liquid state, which is costly.