What Are The Basic Steps Of Manufacturing Composites?

Composites Manufacturing is a process which makes use of various components and techniques to produce a final product that is more durable and stronger than traditional materials. This process can be used in many different industries that range from construction to transportation. This article will provide an overview of the essential steps of composite parts manufacturing and explain the reason why it's such a valuable tool.

These are the four major steps in composites production. However, the order of the operation may differ depending on the type of application or manufacturing process.

Impregnation

The resin is then applied to the previously dried fiber. This makes sure that the fiber is completely coated throughout the process. The outcome of this process is known as the lamina. Different techniques are employed to obtain a uniform and complete impregnation, although automation is the most commonly used method today and uses the compaction roller to make sure that the resin flows uniformly across fibers.

For example, in a filament winding process fibers are pushed through the resin bath to impregnation. When a hand-lay-up procedure is used the materials are already impregnated by the supplier of the material in a controlled setting are utilized. This is done at the impregnation line in the automated fiber placement process. Preparation is the name given to the end product of an impregnation device.

Layup

The composite laminates are made by either using the fiber after impregnating it or by placing the fiber/resin preregs at the desired locations and in the desired orientations. The composite part thickness is built up by placing different layers of the material.

The relative motions between the mandrel and the carriage unit affect the distribution of fibers within filament winding. The fiber has directional strength, and has to be placed in a specific orientation.

The preform, which is dry, is inserted inside a mold, allowing it to be infused with the RTM process. The preform is made by braiding, AFP, cutting & kitting etc. The resin is then injected into and then consolidated to form the laminate.

Consolidation

When a consolidation process is carried out it is the application of pressure to create the monolithic form from distinct plies while simultaneously eliminating any voids or volatiles, while to achieve the desired volume fraction of fibers within the component, and attaining the right dimensions and tolerances.

The pressure is obtained by vacuum, compaction or pressing or wrapping. Most epoxy resins carbon fiber parts manufacturing utilize vacuum as a method of consolidating. The AFP methods apply the consolidation force at the time of layup with a compaction roller. RTM will consolidate during the process of press impregnation. When winding filaments the force of consolidation is initially applied during winding, and then by wrapping the winding under tension with a thin film of plastic.

Solidification

Solidification is the final step. It could be less than a minute for thermoplastics and up to 120 hours for thermosets that use thermosets. For proper consolidation, either vacuum or positive pressure is maintained.

The rate of solidification in thermoset composites is contingent on the formulation of the resin and the cure time. To speed up the cure of the resin, heat is used during the process of solidification. For thermoset resins usually the higher the temperature at which the cure is completed more rapid the cross-linking process. However, careful attention must be paid to the data sheet of the material in order for the best result.

In thermoplastics, there's no chemical change during the process of solidification. Therefore, solidification takes the most time and temperatures. The cooling rate is what determines the rate at which thermoplastic processing occurs. The process will yield more plastic if it has a shorter time for solidification.

Summary

The world of composites has many conditionals, therefore making a blanket statement can be difficult, however the four steps listed below are most common elements in all composites production processes regardless of whether the product is thermoplastics or thermosets. The order and methods of carrying out the steps may differ based on the type of material, the manufacturing process and the final requirements.

The thermoplastic and prepreg materials are used to impregnate the fibers before the layup. They are most commonly employed in aerospace manufacturing where the standards are high. Parts with lower requirements that are used for leisure and sports equipment (excluding high-performance equipment), would generally perform the layup and then inject the fibers using resin. Consolidation is independent of it being solidified, but parts cannot be treated (thermosets) or solidified (thermoplastics) without simultaneous consolidation.