A Guide to Understanding the Composites Manufacturing Process

Composite Manufacturing

There is a $22.2 billion contribution to the US economy by the composite industry. It’s an industry that is an economic force and acts as a fuel to the American economy. It is not possible for anyone to understand this kind of an industry without at least getting to understand the composites manufacturing processes.

It is only right to get to know what goes on in the composite industry by looking at its main processes.

This piece of writing will give you extensive knowledge concerning this. First, composites manufacturing processes are three. These are cast polymer molding, closed molding, and open molding.

Within these molding categories, there are a variety of processing methods that have their benefits. Let us have a look at all of them for a better understanding.

Closed Molding

In this molding category, there is a processing of composite materials.

These materials are cured inside a two-sided mold or a vacuum bag and closed to the atmosphere. There are two cases that closed molding may be considered for, and they are if there is a requirement of high production volume and if there is a two-sided finish that is needed.

Vacuum Bag Molding

Vacuum bag molding is a manufacturing process that helps in improving the laminate’s mechanical attributes.

There is a concentration of high-fiber that provides better adhesion. This normally happens between layers of sandwich construction.

In addition to this, there is also an elimination of excess resin by vacuum bag molding. It is when structures are made using hand lay-up techniques or open molding that this excess resin builds up.

Vacuum Infusion Process

It’s a technique makes the resin move into a laminate by using vacuum pressure. This kind of process usually helps with the manufacturing of very large structures.

It also helps with offering substantial emissions reductions as compared to wet lay-up vacuum bagging and open-molding processing. It also produces strong lightweight laminates. The vacuum infusion process is the same as molding in that it uses low-cost tooling, and it also requires minimal equipment.

Continuous Lamination

It’s a process that is used to make the corrugated or flat panel and sheet products. These products are mainly used in electrical insulating materials, building panels, skylights, road signs, RV sidewalls, and trucks. This is a process that is highly automated and has to work with a combination of resin and fibers.

After this, they are guided through a conveyor process after being sandwiched between two plastic carrier films. A composite panel is then formed after in an oven and heating zone.

The resin and the sheet form a roller’s shape and are then cured. There is then an automatic trimming of the panels to the desired length and width.

Compression Molding

This is a process which has two similar molds sandwiching composite materials. This is done under heat that is usually from 250° F to 400° F, and under intense pressure. It is then done until the part is fixed.

High part uniformity and fast molding cycles are featured in compression molding.

This is the kind of process that can be automated. Moreover, this process provides nice surface finishes and design flexibility, and the labor costs are low.


This is a process that can modify composites into bars and rods that are long and consistent.

There are continuous reinforcement strands that will be passed along a resin bath so that they can be saturated. After this, the composites are sculpted into extended lengths after being pulled through heated steel molds.

The finished products are very strong, and the labor costs are low. The process is also used to make products such as golf club shafts, fishing rods, tubing, pipes, channels, and beams.

Resin Transfer Molding

This kind of molding is sometimes known as liquid molding. It is a closed-molding method that involves reinforced material being loaded into a mold that is usually closed.

Resin is then pumped into the mold after it has been clamped. This is done under pressure and through injection ports. On all the exposed surfaces, there are some smooth finishes done, and there is a production of complex parts with this kind of process.

The cycles are speedy sometimes, and the process can be highly automated or just simple. Any combination of orientation and materials can be used by laying up reinforcement material inside the mold. These reinforcements also include 3-D reinforcements.

Open Molding

When it comes to this process, fiber reinforcements and resins, which are raw materials, are made to cure and harden by being exposed to air. This process also has its different t processes that include filament winding, casting, spray-up, and hand lay-up.

Hand Lay-up

This process is the least expensive and the most common among all the open-molding processes. This is because, among all the other processes in open molding, this is the one that requires the least amount of equipment.

In a mold, fiber reinforcements are placed by hand and then resin applied with a roller or a brush. Hand lay-up is a process that is used to make both small and large items that include showers, tubs, storage tanks, and boats.


This process is somehow similar to hand lay-up. However, it uses a chopper gun, which is a piece of special equipment. This special equipment helps in cutting reinforcement materials into short fibers and then adding the resin.

The mixture, which is called chop, is then deposited onto a molding surface. This is a process that is typically used to produce large quantities, and that is more automated than hand lay-up.

Filament Winding

This is an automated process that applies continuous strands of fiber reinforcements that are resin-saturated over a mold that is a rotating cylindrical.

This process is also used to create hollow products like chemical storage tanks, stacks, pipes, casings, and rocket motor. It is also a process that is not as labor-intense as the other open-molding processes.

Beyond Composites Manufacturing

The economy can not thrive without composite manufacturing. Clearly, there are very many products that are made using this kind of manufacturing that we can never do without.

Contact us for more composites manufacturing information.

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