The Prepreg Layup Process

Prepregs are becoming increasingly popular in the composite industry due to their impeccable surface finish, consistency, and ease of use. Manufacturers can rely on prepregs to improve part uniformity, reduce excess resin weight, and eliminate resin voids in finished products. A critical factor in using prepregs for manufacturing is providing adequate cold storage as well as a combination of heat and pressure for curing.

This blog will help you understand the prepreg layup process and highlight the benefits. We will also provide step-by-step instructions for the typical hand layup process and some vital tips for creating high-quality prepregs.

Prepreg Layup Process

The prepreg layup process involves placing layers of resin-impregnated reinforcement or other reinforcement materials in a precise position by hand. Workers manually manipulate individual plies and place them in position on a mold leaving no air pockets between each layer. The hand layup method delivers a consistent high-performance structure, but the process involves primarily manual labor and cannot easily be automated.

The Benefits of a Prepreg Layup

There are many benefits to using the prepreg layup process to produce high-performance composite materials. These benefits include: 

• Complex designs. Manufacturers can produce high-quality products with intricate design features.
• Cost-effective. Costs remain low with no need for complicated and expensive equipment. 
• Adaptable. The prepreg layup process is adaptable to new parts and changes in design.
• Easy to learn. It is relatively easy to learn the process and technology. 

The Prepreg Layup Procedure: Step-by-Step Instructions

The average bagging operation will follow these steps to complete the layup process:

1. Add a release medium between the tool and the part.
2. Place layup on the application tool.
3. Apply peel-ply or perforated parting film over the layup.
4. Place bleeder material over layup in one or more layers. This critical step removes air pockets and excess resin from the workpiece to deliver higher-quality results.
5. Add at least two thermocouple wires. Additional wires may be needed, depending on the workpiece size.
6. Initiate the vacuum bagging process.

Tips for Quality Prepreg Layups

The highest-quality prepreg layups require clean processing. The following tips help manufacturers deliver the best quality prepregs:

• Production workers should wear lint-free white cotton gloves. Certain types of latex gloves can be used while other types of rubber gloves are unacceptable as they can leave fingerprints and adhere to the workpiece. These issues can lead to voids in the finished product.
• Discard any cotton gloves upon soiling.
• Production line workers should avoid the use of hand creams.
• Dermatitis, soreness, or cracked skin are preventable with frequent hand washing.

High-Performance Prepregs From APCM

At APCM, we have delivered solutions in small and large volumes for manufacturers, hobbyists, and designers since 1992. We are a thermoset epoxy prepreg developer and a leader in prepreg manufacturing. We can help you reach your goals with stronger and lighter materials through our high-quality prepregs. Contact us today to speak with our composite material experts.