Few Types of Composite Manufacturing Processes

 The Design and Manufacturing of Structural Composites provides an overview of the key manufacturing challenges when processing fibre-reinforced composites. What's special about composite materials is that the material is created at the same time as the structure. This means that there is a very close relationship between the component, the manufacturing process, and the resulting mechanical performance.

There are three types of composite manufacturing processes: open moulding, closed moulding, and cast polymer moulding and there are various processing methods within these moulding categories, each with its own advantages. These three types of composite manufacturing processes can be learned in the composite manufacturing training provided by the world-class DATUM Limited, the leading provider of technical knowledge.

Here is an in-depth explanation of what those processes are and what they do:

1. Open Moulding
Open moulding exposes the raw materials (resin and fibre reinforcement) to air to cure. Open moulding uses various processes such as hand laying, spraying, casting, and filament winding.

v    Hand Lay-up
Hand Lay-up is the most common and cost-effective open moulding process because it requires minimal equipment. The fibre reinforcement is placed into the mould by hand, and the resin is applied with a brush or roller. This process is used to create items large and small, such as boats, storage tanks, bathtubs, and showers.

v    Spray up
Spray-up or chopping is an open moulding process similar to hand lay-on, suitable for manufacturing boats, tanks, transportation components, and bathtub/shower units of various shapes and sizes. Cut laminates are more conformable and may be faster to manufacture than hand-applied laminates when forming complex shapes.

v    Filament Winding
Filament winding is an automated process in which continuous fibre-reinforced strands soaked in resin are applied onto a rotating cylindrical mould. It is used to manufacture hollow products such as rocket motor casings, pipes, chimneys, and chemical storage tanks. Filament winding is less labour-intensive compared to other open-forming processes.

2. Closed moulding
In closed moulding, the raw materials (fibres and resin) are cured in a double-sided mould or vacuum bag (with air excluded). The closed moulding process is usually automated and requires specialized equipment. Therefore, they are mainly used in large plants that produce large quantities of up to 500,000 parts per year.

v    Vacuum Bag Moulding
This manufacturing process is designed to improve the mechanical properties of laminates (two or more fibre-reinforced layers bonded together with resin). Create a vacuum to force out trapped air and excess resin and compress the laminate. The high fibre concentration improves adhesion (between the layers of the sandwich structure). In addition, vacuum bag moulding helps remove excess resin that accumulates when creating structures using hand layup (open moulding) techniques.

v    Vacuum Infusion Processing
Vacuum injection processing (VIP) is a technique that uses vacuum pressure to inject resin into the laminate. Vacuum injection is typically used to create very large structures. Vacuum infusion creates a strong, lightweight laminate with significant emissions reductions (compared to open-mould processing and wet-process vacuum packaging). This process uses the same inexpensive tools as open moulding and requires minimal equipment.

v    Resin transfer moulding
Resin transfer moulding (RTM), also known as liquid moulding, is a sealed process in which reinforcing material is filled into a closed mould, the mould is clamped in place, and resin is pumped under pressure (through an injection port). It is a moulding process. This process creates complex parts with a smooth finish on all exposed surfaces. Processes can be simple or highly automated, with short cycle times. By dry-placing the reinforcement into the mould, any combination of materials and orientations can be used, including 3D reinforcement.

v    Compression Moulding
The process of compression moulding involves sandwiching composite materials between two matching moulds under high pressure and heat (250–400 °F) until they solidify. This technology allows rapid curing of large quantities of complex glass fibre-reinforced polymer parts. Compression moulding is characterized by fast moulding cycles and high part uniformity. These processes can be automated. Additionally, labour costs are low, design flexibility is high, and beautiful results are achieved.

v    Pultrusion
Pultrusion is used to form composite materials into long, uniform shapes, such as rods. The continuously reinforced strands are drawn through a resin bath to impregnate them and then drawn through a heated steel mould to form the composite into continuous lengths. This process is continuous and can be easily automated. Labour costs are low, and finished products are very stable. Pultrusion is used to make products such as beams, ducts, pipes, tubes, fishing rods, and golf club shafts.

There are more sub-categories of closed moulding that you will learn in composite manufacturing training at DATUM Limited. DATUM's motto is to empower and educate people with technical knowledge and improve their manufacturing skills. There, you can learn about further sub-categories of closed moulding, like reinforced reaction injection moulding, continuous lamination, and more.
The training will include in-depth training on all these processes and the third process, cast polymer moulding. Not just that. From technical courses in composite materials, advanced engineering, and manufacturing to project management, Six Sigma, fire protection, and aerospace quality assurance, DATUM's design courses meet your professional and business needs.