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What are the Manufacturing Basics of Advanced Composites?

Updated: Apr 4, 2022

This article will be focused on basic manufacturing techniques, which are the easiest for beginner manufacturers to get started with producing composite products.

Producing parts from advanced composites

When producing parts from advanced composites, many factors need to be taken into account when choosing the appropriate manufacturing process.

The most common practice, and subject of this article, is to do everything by hand, through a process called manual layup. This begins with taking a sheet made up of the desired fiber and cutting it to the correct size and outline necessary to fit the shape of the mold.

A predetermined number of sections (called plies) are layered until the desired thickness is reached. There are multiple types of material used in composites manufacturing, but we will focus on unidirectional from here on out.

Image 1: Unidirectional Carbon Fiber

As Image 1 shows, a sheet of unidirectional fiber has all the fibers going in the same direction. The other types of fiber sheets can be biaxial, triaxial, twill, etc. where fibers can go in multiple different directions, creating strength no matter the orientation.

When using unidirectional fiber, it is of utmost importance that the fibers are in the correct orientation, as this dictates the strength of the final part.

Even a few degrees of fiber deviation can have detrimental effects on the final part. Once the sheets are laid upon the mold, the material has to be 'wetted'. Wetting is when the uncured matrix is applied onto the fibers until they become totally saturated.

After the part is sufficiently wetted out, the 'bagging' process can begin. Bagging is a multistep process where the end result is an airtight seal between a plastic film and the mold.

Bagging consists of a l