What is the Process of Compression Molding SMC?

SMC Compression Molding is a manufacturing process that uses Sheet Molding Compound (SMC) - a fiber-reinforced thermoset composite material - to produce high-strength, lightweight parts through compression under heat and pressure. It is widely used in automotive, aerospace, electrical, and construction industries due to its high strength-to-weight ratio, corrosion resistance, and design flexibility.

Compression Molding Process

1.Preparation Before Compression Molding

Material Cutting：Cut the SMC sheet into suitable shapes and sizes according to the product size and weight requirements.
Mold Preheating: The mold needs to be heated to 140-160°C in advance to ensure uniform temperature (within ±2°C).

2. Main Processes of SMC Compression Molding Process

Adding Raw Material: After strict weight calculation, the cut SMC sheets are put into the mold, usually with a feeding area between 50% and 90%. For asymmetric complex products, the feeding position should ensure that the material flow reaches all ends of the mold cavity at the same time during molding, and the feeding method should be conducive to exhaust.
Forming: After the mold is closed, the high temperature and high pressure are maintained. Usually, the holding time is between 2-10 minutes depending on the product requirements. During the molding process, various molding process parameters and press operating conditions should be reasonably selected.

3.Post-processing

Demoulding: Control the press mould to open and take the product out of the mould.
Processing: Trim the waste edges, polish the burrs between the mold edges and gaps, and get semi-finished products. Products that pass the quality inspection are transferred to the warehouse, and unqualified products are handled accordingly.

Key Advantages

• High Production Efficiency: It can realize automated mass production and shorten the molding cycle.
• Excellent Product Performance: It has the characteristics of high mechanical strength, stable dimensional accuracy and good surface quality.
• Strong Material Adaptability: It is suitable for a variety of resin systems (such as unsaturated polyester), can be filled with glass fiber and other reinforcing materials.
• Flexible Design: It can form complex structural parts and reduce subsequent processing steps.
• Environmental Protection and Energy Saving: Its production process has less pollution and high material utilization rate.

Application in my Country's Automobile Industry

• BYD Automobile tries to use SMC to manufacture battery upper cover in the development of new models to reduce the weight of the whole vehicle and improve the degree of design freedom.
• Luxury buses (such as JAC, Yutong, etc.) widely use SMC technology in front and rear bumpers, fenders, wheel guards, instrument panels and other parts to reduce the weight of the body and improve production efficiency.

Conclusion: The Future of SMC - Innovation
With its comprehensive advantages in efficiency, cost and performance, SMC has become one of the mainstream processes for mass production of composite materials, especially in the automotive and industrial fields. Whether it can become the "absolute future" in the future depends on whether it can break through technical bottlenecks, build a more complete industrial chain ecology, and seize emerging demands in the wave of lightweight and intelligentization. For industries that pursue scale, high performance and low cost, SMC is not only an "option", but also a "must-have option" - but only continuous innovation can make the "future" truly come true.