Injection design is a highly specialized process that shapes different types of plastics into a variety of items, including small bottle caps, large kit car body shells and boat hulls. It has been an integral part in mass-production manufacturing since its invention in 1851, and injection design is used in over 30% of all plastics on the market. Many types of plastics including thermoplastics, polymers, thermosets, and elastomers are used in injection design. The unique equipment used for injection design also lends itself to the creation of custom injection molding in addition to standard, mass produced injection molding parts. The equipment, technique, and correct plastics work together to produce plastic injection molding in its modern form.
A vast number of commercial and consumer products use injection design. Some of the more common types of plastic molding include items like pocket combs, plastic packaging, and parts for new vehicles, like dashboards. Sink plugs, parts for toys, and model kits are common on the production line floors as well. Injection molding techniques are used for larger goods as well including plastic garbage cans, recycling bins, and milk crates used by dairies. There are literally thousands of plastic products available that were created through the injection mold process.
The type of plastic used in the injection mold equipment depends heavily on what kinds of products are being manufactured during the injection design process. In most cases, the plastics are blends formulated to enhance their natural benefits like durability, aptitude for the function desired, and in some cases, how well the blends can retain physical characteristics such as shape and color. The engineers and product designers in each firm make careful decisions regarding which type of plastics are best for the products on the line. Thermosetting polymers such as epoxy and phenolic resin are used in products such as milk bottle crates. Thermoplastic polymers such as nylon and polystyrene are used when a degree of elasticity is needed, including foam and plastic cutlery.
The equipment used to inject plastic into molds typically consists of three parts. The heating unit is responsible for ensuring the plastic material is fluid and ready for the mold. Material hoppers hold the plastic until it's time to be set into the correct injection molding. The injection ram is used to push the molten plastic from the material hopper to the mold where it can harden into the desired shape.