What are the disadvantages of compression molding?

1, Low production efficiency
A significant disadvantage of compression molding is relatively low production efficiency. This is mainly due to its long molding cycle. In the compression molding process, the raw materials need to go through multiple stages such as preheating, pressurization, melting, and solidification in the mold cavity to finally obtain the desired plastic products. This process is not only time-consuming, but also difficult to significantly shorten through simple technical means. Therefore, compared with efficient molding technologies such as injection molding, compression molding has significant disadvantages in production efficiency.
2, High labor intensity
Another significant disadvantage of compression molding technology is its high labor intensity. This is mainly reflected in multiple aspects such as raw material pretreatment, mold loading and unloading, monitoring of the molding process, and extraction of finished products. Due to the fact that compression molding usually requires manual operation, it not only increases the labor intensity of workers, but may also lead to safety hazards in the production process. In addition, with the increase of labor costs, the high labor intensity of compression molding has further pushed up its production costs.
3, Short die life
During the compression molding process, the mold is subjected to the combined effects of high temperature and high pressure, which places extremely high demands on its material properties. However, even with high-performance mold materials, it is impossible to completely avoid mold wear and damage. Especially when producing large or complex shaped plastic products, the stress situation of the mold is more complex, and the risk of wear and damage is also higher. Therefore, the lifespan of compression molding molds is relatively short, requiring frequent replacement and maintenance, further increasing production costs and downtime.
4, The precision of plastic parts is difficult to control
During the compression molding process, the poor flowability of raw materials and the complexity of mold cavities make it difficult to effectively control the dimensional and shape accuracy of plastic parts. This problem is particularly prominent in the production of thin-walled, slender, or complex shaped plastic products. The insufficient precision of plastic parts not only affects the appearance quality of the product, but may also lead to functional failure or safety hazards during use. Therefore, for plastic products with high precision requirements, compression molding may not be the best choice.
5, Not easy to achieve automated production
The difficulty in automating the compression molding process is another significant drawback. Due to factors such as long molding cycles, high labor intensity, and complex mold loading and unloading, compression molding is difficult to achieve efficient automated production. Although in recent years, with the continuous development of automation technology, some advanced automation equipment and systems have been introduced into compression molding production lines, their overall automation level is still relatively low. This not only limits the production efficiency and application scope of compression molding technology, but also increases production costs and operational difficulties.
6, Limited adaptability of raw materials
The adaptability of raw materials in compression molding technology is relatively limited. Due to the limitations of its molding principle and characteristics, compression molding is mainly suitable for thermosetting plastics and some thermoplastic plastics with high melt viscosity. For some thermoplastic materials with good fluidity, such as polyethylene, polypropylene, etc., the quality of the plastic parts may be poor due to insufficient flow of raw materials in the mold cavity. Therefore, when choosing compression molding technology, it is necessary to fully consider the applicability of raw materials and the molding effect.
7, Environmental impact and sustainability challenges
In addition, compression molding technology also faces challenges in terms of environmental impact and sustainability. During the production process, compression molding generates a large amount of waste and emissions, causing certain pollution to the environment. Meanwhile, due to factors such as short mold life, frequent replacement, and limited adaptability of raw materials, the resource and energy consumption of compression molding in the production process is relatively high. This not only increases production costs, but may also have long-term adverse effects on the ecological environment.