Advantages and Disadvantages of Compression Molding

What is Compression Molding?

Compression molding is the operation of first putting powdered, granular, or fibrous plastic into the mold cavity at the molding temperature, and then closing the mold to press to shape and solidify it. Compression molding materials include thermosetting plastics, thermoplastics, and rubber materials.

Advantages of Compression Molding

1. In the custom compression molding process, the loss of raw materials is small and will not cause too much loss (usually 2% to 5% of product quality).
2. The internal stress of the product is very low, the warpage deformation is also small, and the mechanical properties are relatively stable.
3. The wear of the mold cavity is small, and the maintenance cost of the mold is low.
4. The cost of molding equipment is low, its mold structure is simpler, and its manufacturing cost is usually lower than that of injection molds or transfer molding molds.
5. Larger flat products can be formed. The size of the product that can be molded by molding is only determined by the clamping force of the existing molding machine and the size of the template.
6. The shrinkage of the product is small and the repeatability is good.
7. A mold with a large number of cavities can be placed on a given template, with high productivity.
8. Compa re with high-precision plastic injection molding, it can be adapted to automatic feeding and automatic removal of products.
9. High production efficiency, easy-to-realize specialized and automated production.
10. The product has high dimensional accuracy and good repeatability.
11. The surface is smooth and clean without secondary modification.
12. Products with complex structures can be formed at one time.
13. Mass production and relatively low price.

Disadvantages of Compression Molding

1. The molding cycle in the entire manufacturing process is long, the efficiency is low, and the staff has a large physical consumption.
2. It is not suitable for molding complex products with dents, side slopes, or small holes.
3. In the production process, it is difficult to completely fill the mold, and there are certain technical requirements.
4. After the curing stage is over, different products have different stiffness, which affects product performance.
5. For products with high dimensional accuracy requirements (especially for multi-cavity molds), the process is somewhat short.
6. The flash of the final product is thick, and the workload of removing the flash is large.
7. The disadvantage of compression molding lies in the complexity of mold manufacturing, large investment, and the limitation of the press, which is most suitable for mass production of small and medium composite materials, such as rubber compression molding and compression molding plastic.