What are the drawbacks of rotational molding?

1, The cost of raw materials is relatively high
The plastic raw materials used in the rotational molding process are mostly in the form of granules, which need to be ground into powder before they can be used. The grinding process not only increases production costs, but also the quality of grinding is one of the important factors in the rotational molding process. If the grinding is not uniform, it may affect the quality of the finished product. In addition, although it has been developed for many years, the types of plastic raw materials suitable for rotational molding process are still limited, and polyethylene accounts for more than 90% of rotational molding materials. The singularity of this raw material limits the diversity of raw material selection in the rotational molding process and further increases the cost of raw materials.
2, Low production efficiency and high energy consumption
Each product formed by the rotational molding process requires heating the mold and the resin powder inside to the melting temperature of the resin, and then cooling to room temperature. This process takes a long time, usually several tens of minutes or even longer. Therefore, the production efficiency of rotational molding process is relatively low and not suitable for large-scale production of small products. Meanwhile, during the molding process, the mold and bracket are repeatedly subjected to alternating high and low temperatures, resulting in significant energy loss. This not only increases production costs, but also puts higher demands on the durability of the equipment.
3, High labor intensity in production
The loading and demolding processes in rotational molding usually require manual operation. These processes are not only tedious and complex, but also require a certain level of technical expertise and experience. Therefore, the labor intensity of rotational molding process is high, which not only increases labor costs but may also affect production efficiency. In addition, errors in manual operation may also lead to unstable product quality.
4, Solid products are difficult to form
The rotational molding process mainly relies on the melting and bonding of plastic on the inner wall of the mold. However, solid products require plastic to be evenly distributed inside the mold and fill the entire space, which is difficult to achieve during the rotational molding process. Therefore, the rotational molding process has limitations in preparing solid products. If solid products need to be made, other molding methods or additional processing are usually required.
5, Poor dimensional accuracy of the product
The size of rotational molded products is influenced by various factors, such as the type of raw material, cooling rate, release agent, etc. The changes in these factors may lead to changes in the size of the product. Therefore, the dimensional accuracy of rotational molded products is difficult to control. In practical applications, this may lead to problems with the product during assembly or use. In order to improve dimensional accuracy, stricter process control and testing methods are usually required.
6, The shape of the product is limited
The rotational molding process is not effective in preparing products with significant differences in wall thickness and sudden changes in wall thickness. Due to the influence of various factors such as mold shape, rotation speed, heating temperature, etc., the melting and flow of plastic may lead to uneven wall thickness distribution of the product. In addition, the rotational molding process also faces challenges in preparing flat side parts. Due to the difficulty in obtaining uniform heating and melting flow during the rotation of the mold for flat side parts, it may lead to problems such as uneven surface and thickness of the product. These issues limit the application of rotational molding technology in the preparation of complex shaped products.
7, High requirements for equipment and processes
The rotational molding process requires professional equipment and process support. These devices and processes are usually complex and expensive, requiring professional technicians to operate and maintain them. In addition, the rotational molding process also has high requirements for the design and manufacturing of molds. If the mold design is unreasonable or the manufacturing accuracy is not high enough, it may affect the quality and production efficiency of the product.