Introduction To HP-RTM And Wet Molding Processes for Composites

HP-RTM, short for High Pressure Resin Transfer Molding, is a manufacturing process that involves injecting resin under high pressure into a vacuum-sealed mold pre-laid with fiber-reinforced materials and pre-positioned inserts. The process includes resin flow filling, impregnation, curing, and demolding to produce composite products.

Keyword Explanations:

High Pressure:
In the context of HP-RTM, "high pressure" refers to the significantly increased injection pressure compared to traditional RTM (Resin Transfer Molding). The injection pressure in HP-RTM can reach up to 80 bar. High-pressure injection allows resin to quickly reach every corner of the mold, enabling higher fiber content and enhanced product performance. This makes the process particularly suitable for complex-shaped components.

Pre-laid:
The "pre-laid" fiber-reinforced materials refer to pre-cut and pre-formed fiber materials that are placed in the mold prior to the resin injection process.

Pre-positioned Inserts:
Inserts refer to components placed inside the mold before the molding process begins. These inserts, made of either metallic or non-metallic materials, become embedded within the structure of the finished product and are non-removable. Whether inserts are required depends on the structural design of the product.

The HP-RTM molding process is an optimized version of the traditional RTM process, designed to improve production efficiency and product performance. Based on different optimization directions, other processes have been developed on the foundation of RTM to achieve further advancements. One such example is HP-CRTM (High Pressure Compression Resin Transfer Molding), a process owned by HRC.

1. Overview of HP-CRTM Process:

2. In the HP-CRTM process, prior to resin injection, the upper mold is lifted by 0.5 to 1 mm, increasing the gap in the sealed mold cavity. This adjustment allows for wider resin channels, reducing resin flow resistance. Once the resin injection is complete, the mold is fully closed under high pressure. During this closure, the resin system flows under the compression pressure to fill the mold. The relatively lower molding pressure ensures the following advantages:

3. Prevention of fiber distortion, maintaining consistent fiber alignment.

4. High injection speed, improving overall production efficiency.

5. This process retains the benefits of HP-RTM while addressing specific challenges, offering enhanced performance for complex composite components.

HP-RTM (High Pressure Resin Transfer Molding) is one of the most widely used composite manufacturing processes across multiple industries. Its advantages include lower costs, shorter production cycles, high-volume capacity, and superior product quality (such as excellent surface finish) compared to traditional RTM processes.

This process is extensively applied in industries such as:

• Automotive Manufacturing

• Shipbuilding

• Aircraft Manufacturing

• Agricultural Machinery

• Railway Transportation

• Wind Power Generation

• Sports Equipment

HP-RTM’s versatility and efficiency make it an ideal solution for producing high-performance composite components in a wide range of applications.