Plastic processing covers a broad set of shaping routes, each with different tooling, cycle, material, and quality implications. For engineers and sourcing teams, the right method depends on part geometry, polymer behavior, mold or die investment, tolerance, surface finish, and production volume. The overview below groups common techniques by how they form plastic and notes where each is typically used. 
Injection Molding and Extrusion
Injection molding forms industrial products by forcing molten plastic or rubber into a closed mold. The injection molding machine and mold work together to shape thermoplastics or thermosetting materials; the category also includes injection compression molding and die-casting variants. Extrusion, by contrast, heats and plasticizes material in the extruder barrel and screw while pushing it forward. The material then passes continuously through a die, producing long products or semi-finished profiles with a defined cross-section.
Hollow, Rotational, and Sheet-Based Forming
Rotational molding—also called roto-molding or rotational casting—places a measured charge of liquid or powder plastic in a closed mold. The mold rotates on two perpendicular axes under heat, allowing the material to melt and coat the cavity evenly. After cooling and solidification, the part is demolded. Blow molding, or hollow blow molding, uses a thermoplastic tube made by extrusion or injection molding. While hot or reheated, the tube is placed in a split mold; compressed air inflates it against the walls; cooling and demolding yield a hollow product.
Vacuum forming heats a flat plastic sheet until soft and uses vacuum to pull it onto a mold surface; after cooling, the sheet retains the molded shape. This technique is widely used across industries. Thermoforming is a more specialized sheet process: thermoplastic sheet is heated, clamped, and forced against a mold, then cooled and trimmed into a finished part. 
Compression, Thermoset, and Pressure-Based Methods
Compression molding, also known as press molding, puts powder, granules, or fiber-based plastic into a heated cavity. The mold closes under pressure, forming and curing the material; the process works with thermosetting plastics, thermoplastics, and rubber. Cold compression molding performs the compression step at room temperature, after which the part may be heated or chemically cured to reach the required properties. Hot pressing for thermosets heats the material until it softens, applies pressure to shape it, and continues heating to crosslink and cure it.
Resin transfer molding (RTM) injects resin into a closed mold to impregnate reinforcement materials, then cures the resin. Because RTM avoids pre-impregnated materials and autoclaves, it can lower equipment and production costs; it is widely used in aerospace, automotive, and shipbuilding. Another pressure-based route presses a billet in a mold cavity with a punch or die, causing the material to flow plastically and take the tool shape; this is often described as plastic forging or die pressing.
Sheet, Foam, Composite, Coating, and Casting Processes
Calendering passes molten thermoplastic through gaps between two or more parallel, counter-rotating rolls. The material is compressed, stretched, and flattened into film or sheet with controlled dimensions and quality. Foaming introduces a foaming agent into materials such as PVC, PE, and PS to create a microcellular structure; both thermosetting and thermoplastic plastics can be converted into foam, making this a major segment of plastic processing.
Filament winding wraps resin-impregnated continuous fibers, fabric strips, or prepreg yarn around a mandrel in a set pattern. After curing and demolding, the composite product is obtained. Lamination bonds multiple layers of the same or different materials under heat and pressure into one structure and is used in plastic and rubber processing. Coating applies plastic sol or organic solutions to fabric, paper, or other surfaces to produce artificial leather, oilcloth, plastic wallpaper, and related items; powdered plastics can also be applied to metal surfaces. Casting is one of the earlier plastic processing methods: liquid monomers or prepolymers are poured into a mold, where they polymerize into a solid. Modern casting also uses polymer solutions, dispersions, or melts, which expands its applications. Thermoplastic melt shaping with room-temperature curing relies on materials that flow under processing conditions and solidify at room temperature; with suitable tools, the material is shaped while molten and then cured at room temperature.
Additive Manufacturing and Process Selection
3D printing is a rapid prototyping method that builds objects layer by layer from digital files using powdered metals, plastics, or other materials. It is widely used in mold manufacturing and industrial design and is increasingly applied to finished components. Common materials include nylon, PLA, ABS resin, durable nylon, gypsum, aluminum, titanium alloy, stainless steel, and rubber. When comparing plastic processing methods, teams should check material compatibility, tooling needs, cycle time, dimensional control, surface quality, and total cost. A process that suits a prototype may not be the best fit for high-volume production. 
To learn more about TCHD Plastic Injection Molding, contact the team for guidance on matching part design and production goals to the right process.