Carbon Fiber Fabric Molding Processes: A Comparison of Resin Transfer Molding (RTM) and Hot Press Molding (HP) 

Introduction:

Carbon fiber fabric is widely used in industries such as aerospace, automotive, and sports equipment due to its excellent strength-to-weight ratio and durability. The molding process directly affects the final product’s quality, performance, and cost. Among the various molding techniques, Resin Transfer Molding (RTM) and Hot Press Molding (HP) are the most common methods. This article will introduce both processes, compare their pros and cons, and help manufacturers choose the most suitable method based on specific requirements. 

Resin Transfer Molding (RTM) Process and Required Equipment 

Preparation Stage:

• • Equipment:

    • Molds: Typically made of metals like aluminum or steel, molds consist of two parts (upper and lower) to ensure sealing and precision.

    • Prepreg or Dry Carbon Fiber Fabric: Carbon fiber fabric is cut and placed into the mold according to the product design. Prepreg materials, which have resin pre-applied, are also commonly used.

    • Mold Heating System: A mold heating system ensures that the mold reaches the required temperature before resin injection.
      
      

Injection Stage:

• • Equipment:

    • Resin Injection System: Includes resin pumps, pipes, and injection heads, which ensure the resin is evenly injected into the mold and prevent air bubbles.

    • Vacuum Equipment (optional): Some processes use vacuum equipment to evacuate air from the mold, ensuring that resin fully impregnates the fibers.

Curing Stage:

• • Equipment:

    • Curing System: The resin is cured through heating and pressure to ensure uniform distribution inside the mold.

    • Pressing Equipment (Hot Press or Hydraulic Press): Hydraulic systems apply pressure to ensure uniform curing of the resin.

Cooling Stage:

• • Equipment:

    • Cooling System: The cooling system helps to lower the temperature of the cured product to ensure stability and protect the mold.

 Hot Press Molding (HP) Process and Required Equipment

 Preparation Stage:

• • Equipment:

    • Prepreg or Carbon Fiber Fabric: The prepreg or dry carbon fiber fabric is placed into the mold. Prepreg is typically more suited for hot press molding.

    • Mold: Similar to RTM, molds are used to shape the final product and are usually made of aluminum or steel.

    • Preheating System: Ensures that both the mold and materials reach the desired temperature before pressing.

Heating and Pressing Stage:

• • Equipment:

    • Hot Press Machine: This is the core equipment for hot press molding, providing both heat and pressure to the mold.

    • Heating Plates: These plates are used to uniformly heat the mold and ensure consistent temperature distribution.

    • Hydraulic System: The hydraulic pump applies pressure to compress the material and promote resin curing.

Curing Stage:

• • Equipment:

    • Curing Control System: Ensures the resin cures at the right temperature and pressure.

    • Temperature Control System: Monitors and adjusts temperature in real-time to ensure uniform curing.

Cooling Stage:

• • Equipment:

    • Cooling System: This system uses cooling pipes or fans to rapidly reduce the temperature of the