High Speed Manufacturing of Automotive Composite Parts

Using composites materials is a great way to reduce the weight of a car. Yet, the condition to introduce such materials in higher volume commercial model vehicles is the ability to go fast. The entire process requires a short cycle time of less than 5 minutes for the process to be viable for the automotive mass production volumes.

Fiber reinforced plastics that utilize either glass or carbon fibers as reinforcement materials and thermosetting epoxy resin matrices are an extremely powerful material combination for saving weight in many structural applications.

Specific requirements for the resins include a shorter cure time while retaining the desirable characteristics of traditional epoxy resins. Examples of parts that are produced by high speed processes include leaf springs for light trucks, automotive hoods and chassis assemblies for sports cars.

This article focuses on the development of resins for high speed manufacturing processes such as RTM. RTM is among the leading technologies for the production of structural composite parts for use in the automotive sector.

Today, some of the main bottlenecks in the process are the manufacture of the preform as well as the actual cure of the part. Current approaches to address both of those concerns will be discussed in this article.

In the RTM process, fiber preforms or dry fiber reinforcement is packed into a mold cavity that has the shape of the desired final product. The mold is then closed and clamped. At that time, low viscosity resin is then pumped into the mold under pressure, displacing the air at the edges, until the mod is filled. After the fill cycle is completed, the resin cure cycle starts during which the mold is heated and the resin reacts and crosslinks to become a rigid plastic material.