There are various processes available for the industrialization of composites, selected based on product format, dimensions, and quantity. Key processes include:

Manual Lamination:

This process involves layering fiberglass, aramid, or carbon reinforcement onto an open mold, then manually impregnating them with resin using rollers, brushes, or other tools until all layers are fully wetted and free of air bubbles. Resin polymerization typically occurs at ambient temperature. Manual lamination is utilized for manufacturing parts of different shapes and sizes, as well as molds and prototypes.

Continuous Lamination:

Continuous lamination is an automated process used for producing continuous, corrugated, or smooth panels, either translucent or opaque. Fiberglass reinforcement is combined with resin and pressed between two plastic films, propelled by continuous equipment movement to a heating point where resin polymerization begins.

Vacuum Molding:

Also known as vacuum bagging, this process is employed for fabricating large composite parts using an open mold and a vacuum bag (plastic film or reusable silicone membrane) to shape the component. Resin is rapidly applied to fiber layers with a roller or brush, and before resin polymerization starts, a plastic film or silicone membrane is applied over the mold to create a vacuum pocket. This pocket helps compact the layers over the mold and remove excess resin.

 

Infusion:

Infusion is a widely adopted method for open mold processes, ensuring the production of consistent, high-quality parts. Utilizing vacuum bags or silicone membranes, this process enables the creation of parts with large and intricate structures, incorporating inserts and structural core materials such as PET or PVC. The process involves layering fiberglass reinforcement onto the surface of an open mold covered with a durable plastic film, then sealing it around the perimeter. Once a vacuum is applied, resin infusion is initiated, impregnating the entire piece under atmospheric pressure. After curing, the plastic film is removed, allowing the part to be demolded.

Resin Transfer Molding (RTM):

RTM is a closed mold process where special reinforcement blankets are placed and formed by closing a rigid counter-mold using a vacuum system. Resin is injected into the mold, impregnating all layers of blankets and filling any empty spaces, resulting in a piece with consistent thickness. This method enhances repeatability and provides a smooth finish on both sides of the part, making it suitable for molding complex shapes and surfaces requiring continuous thickness.

Centrifugation:

In this process, cylindrical and hollow shapes are molded in a rotating mold. Fiberglass is cut and deposited directly onto the internal walls of the mold, along with resin and fillers in successive layers. The mold rotation maintains the cylindrical shape and continuous thickness of the piece. Widely used in the manufacturing of tanks and poles.

Spray-up:

Also known as pistol lamination, spray-up involves the simultaneous application of fiberglass and resin onto the mold using special equipment such as laminating guns. Fiberglass rovings are cut into predetermined lengths and mixed with resin before being sprayed onto the mold. Multiple layers are applied until the desired thickness is achieved, with subsequent routing to accommodate the fibers within the mold contours. This method offers cost advantages over manual lamination due to the use of cheaper materials and increased efficiency and speed of operation. It is particularly suitable for mass production of large and complex parts, such as swimming pools, boats, bathtubs, and boat hulls.

Pressing:

Pressing is a process wherein glass fibers are deposited into the mold cavity, and resin is added to impregnate the blanket. The mold is then closed under hydraulic pressure from a press, spreading the resin and completely impregnating the fibers. After pressing and curing the laminate, the mold is opened, and the part is removed. This process can be performed in two ways:

Cold Pressing: Uses a GRP or metallic mold at room temperature, though temperatures typically range between 40°C and 50°C due to the heat generated by the resin system during curing.

Hot Pressing: Utilizes a metal mold heated between 100°C and 140°C for 2 to 4 minutes, resulting in a piece with homogeneous thickness. This method enables the production of high-quality sheets with density, widely used for manufacturing machined parts for electric insulation purposes.

Pultrusion:

Pultrusion is a process used to produce high-strength profiles, rods, and bars for structural applications, which can be solid or hollow and come in various shapes. Glass fibers (including roving, continuous filament blankets (CFM), and special fabrics) are impregnated with resin and pulled through a heated tool mold, giving the piece its final shape before curing and cutting.

Filament Winding:

Filament winding involves an automated open mold utilizing a rotating chuck as a mold. The roving, a fiber filament, is immersed in resin and pulled through rotational force, typically used in manufacturing hollow, cylindrical, high-strength composite products like poles, tubes, storage tanks, and pressure vessels.

SMC (Sheet Molding Compound):

SMC is a combination of unsaturated polyester resin mixed with mineral fillers and reinforced with chopped fiberglass. The process involves three stages: preparation of matrix paste, generation of semi-ready sheets, and formation of the final part through compression or injection molding in heated metal molds. SMC is commonly used for large industrial volume parts, offering superior surface finish, consistent weight, and properties, widely applied in automotive, electrical, and construction industries.

BMC (Bulk Mold Compound):

BMC is another combination of unsaturated polyester resin, mineral fillers, chopped fiberglass, catalysts, and release agents, used in hot compression or injection molding processes. Injection molding is suitable for complex and large-scale part production, yielding well-polished and shiny surfaces, commonly used in electrical equipment, automotive parts, and other industries.

S-RIM (Structural Reaction Injection Molding):

S-RIM involves an injection and reaction process using polyurethane as a polymer, reinforced with a fiberglass blanket, typically made of continuous filament or long filaments. S-RIM is employed in manufacturing automotive parts with polyurethane filling.