8 Plastic Fabrication Methods & How They Are Used

Compression Molding

Compression molding is a method that works by heating plastic inside of a mold and compressing it with a power presser to form a product.

Rotational Molding

Rotational molding is a method that makes a product by putting heated powdered plastic inside a mold and rotating it. When the mold rotates, the heated plastic sticks and layers against the mold’s internal walls.

Injection Molding

Injection molding is a process where a hopper shoots melted plastic into a mold, the machine cools it in place and then ejects it.

Blow Molding

Blow molding works by placing a molten thermoplastic tube—also known as a parison—into a mold. Then, pressurized air is “blown” onto the parison and the parison expands inside of the mold. When the parison expands, it sticks to the internal walls and creates a hollow product.

Vacuum Casting

Casting also uses a mold but in a different way. The mold, made of silicone, is filled with urethane. The mold is then sealed and a technician uses a vacuum to suck out the air pockets and bubbles. When the bubbles are sucked out, the mold is finalized in the oven and results in a sleek surface.

Plastic Fabrication Machining is used to shape a hard plastic piece by cutting, drilling, or shearing.

Extrusion is a process that heats plastic and then pushes it through a die to shape it.

Thermoforming combines various fabrication processes like vacuum casting. It forms plastic sheets instead of a shaped mold.

Plastic welding is similar to metal welding. The process involves pressing two plastic pieces together, heating them to create a molecular adhesion bond, and then cooling them for the final adhesion.

Lamination is when at least two layers of plastic film are held together by covering another material.

Pultrusion is the process of pulling plastic fibers through liquid resin and a heated metal die. It works to create fiber-reinforced plastics with constant cross-sections.

Forging is the process of forming a plastic shape by hitting it with intense force.

Thermoplastic is a type of plastic that can be softened, melted, and reshaped many times to make new products. If you work with thermoplastic, then you can use molding, welding, forging, extrusion, or vacuum casing.

Injection Plastic Molding Fabrication

Injection molding is ideal for making a high volume of custom-made thermoplastic parts. Injection fabrication makes car parts, medical devices, special tools, and bottle caps.

Plastic Welding

Plastic welding adheres two thermoplastic parts together. This is commonly used for conjoining plumbing pipes.

Forging

Forging shapes thermoplastic parts into tools or kitchen cutlery.

Rotational Plastic Molding Fabrication

Rotational molding makes large, hollow products like tanks, playground slides, and bins. This plastic fabrication method has low tooling costs and is straightforward.

Blow Plastic Molding Fabrication

Blow molding works with thermoplastics to make hollow products with thin walls. This includes products like soda, water, and sauce bottles.

Extrusion

Extrusion makes basic geometrical shapes like rectangles, squares, and spheres. Extrusion products include gutters, pipes, straws, tubes, and window frames.

Vacuum Casting

Vacuum casting is ideal for thermoplastic projects that need an extra smooth surface texture. Since it produces a sleek surface, it’s popular for transparent or opaque products.

Products made from vacuum casting include items such as phone cases, display cases, plastic storage boxes, and refrigerator liners.

Thermoset plastics can be molded, but only once, as it utilizes a polymer that is irreversibly hardened by heat. They cannot be recycled into new products. If you work with thermosets, you use thermoforming, laminating, or compression.

Thermoforming

Thermoforming works well for low production volumes of auto parts.

Lamination

Lamination is good for improving the durability or cosmetics of labels, packages, and prints.

Compression

Compression plastic fabricating creates high volumes of small parts and is known for its ability to make complex shapes.

Pultrusion

Pultrusion plastic fabrication makes flat bars and tubes out of thermosets.

A portable CMM utilizes a probe to gather coordinates for inspection purposes. They can inspect 3D features, compare back to a CAD model, and even inspect GD&T features. Portable CMMs are particularly useful for in-machine and in-process measuring, eliminating the need to transport parts to different locations. This not only ensures accurate measurements but also minimizes the risk of distortion during transportation.

Automated Optical Comparators, like this one, are non-contact measurement devices, and are ideal for plastic part applications under 1ft in size. Their non-contact nature eliminates the risk of plastic distortion, making them ideal for sensitive items like plastic bottles that are susceptible to touch-induced changes.