Plastic forming machines, or plastic molding machines, were developed on the basis of rubber machinery and metal

die-casting Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity. The mold cavity is created using two hardened tool steel dies which have been machined into shape and work similarly ...

machines. After the inception of the polymer injection molding process in the 1870s, plastic-forming machines were rapidly developed up until the 1930s. With the gradual commercialization of plastic molding equipment, injection molding and

extrusion molding Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex c ...

became the most common industrialized processes.

Blow molding Blow molding (or moulding) is a manufacturing process for forming hollow plastic parts. It is also used for forming glass bottles or other hollow shapes. In general, there are three main types of blow molding: extrusion blow molding, injectio ...

is the third-largest plastic molding method after the injection molding and extrusion blow molding methods.

Types of plastic forming machine

Plastic injection molding machine

A plastic injection molding machine injects melted plastic into a mold to make solid plastic parts.

Plastic extrusion machine

A plastic extrusion machine extrudes plastic in a continuous

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. The main machine is usually called the host, and its accompanying equipment are called the plastic auxiliary equipment. Plastic extruders can make plastic film/wrapping, packing tape, corrugated sheets,

plastic lumber Plastic lumber is a plastic form of lumber made of virgin or recycled plastic (PL or RPL, respectively.) It is mostly made of plastic and binders such as fiberglass or rebar; not to be confused with wood-plastic composite lumber. Widely employe ...

, pipes, tubes, insulated wire, monofilament and nets.

Plastic blow molding machine

A plastic blow molding machine inflates a preform or parison inside of a mold to form hollow parts.

Thermoforming

Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, and stamped to a specific shape in a 2-part mold. Or a vacuum can be used to pull the plastic sheet onto the mold in a simplified process known as

vacuum forming Vacuum forming is a simplified version of thermoforming, where a sheet of plastic (in various forms HIPS (High impact polystyrene) for low impact products, or for Bathroom shower trays ABS, and exterior vehicle parts HDPE, plus various other ty ...

. The excess material is trimmed off and recycled.

Rotational molding

Rotational molding involves a heated hollow mold that is filled with a charge or shot weight of material. It is then slowly rotated (usually around two perpendicular axes), causing the softened material to disperse and stick to the walls of the mold forming a hollow part. In order to form an even thickness throughout the part, the mold rotates at all times during the heating phase, and then continues to rotate during the cooling phase to avoid sagging or deformation. Rotocasting is a variant of the process that uses self-curing or UV-curable resins (as opposed to thermoplastics) in an unheated mold.

References

{{Plastics Plastics industry Forming processes