The process of plastic molding involves the creation of molded plastic products using molten polymer resin or molten plastic. Materials such as wood and metal are difficult to mold, especially into configurations that are small and complex. These materials also cannot melt and be reformed, which can lead to a high amount of waste. However, plastic is highly malleable and can be turned, squeezed, twisted, or bent into countless shapes.
Quick links to Plastic Molding Information
Applications of Plastic Molding
Due to its wide range of beneficial properties, plastic has become a highly popular alternative material to wood and metal. Because of its versatility, plastic molding is a wise choice to fabricate a variety of products spanning a wide range of industries, and it is the most common manufacturing technique used to fabricate these products. Items that we see and use every day, such as children’s toys, automobile dashboards, and bottle caps, are made by way of plastic molding.
Plastic molding is used in many of industries, such as:
- Food Service
Materials Commonly Used in Plastic Molding
A popular material to use for plastic molding is a plastic polymer, such as elastomers, thermosets, and thermoplastics. Plastic polymer is a popular choice due to its pliability.
The materials used in plastic molding have differing characteristics. Thermoplastics can be heated and melted down to a pliable state and then molded into a wide range of configurations. Once shaped, the thermoplastic material can be readjusted if necessary. However, in freezing temperatures, thermoplastic can become brittle. Thermosets, including polyimides or melamine resin, are hard and brittle once they dry. Unlike thermoplastics, they cannot be readjusted or remolded once they have set. Elastomers, the most common form of which is rubber, maintain their elastic properties after they have cooled. There are some products that benefit greatly from the elasticity, including tool handles and children’s toys. There are other products where elasticity is required.
Process of Plastic Molding
The first step of the plastic molding process involves placing the desired material, in pellet form, into the machine’s hopper in preparation for melting. Next, the pellets are moved to a chamber where they are heated until they reach a molten liquid state. In this state, manufacturers can add agents such as dyes or other chemicals that will affect the final appearance of the product. Once the molten plastic is mixed, it is placed and enclosed into a mold cavity. With pressure, the material completely conforms to the design of the mold. Cooling agents that circulate cold liquid within the mold assist in the removal of heat from the plastic, allowing the material to cool and fully solidify. Once the material is set, the mold can be split in two, releasing the fully formed product. Sometimes, a set of rods or pins is needed to safely remove the product from the mold. Once removed, the process begins all over again.
Plastic molding involves a prefabricated mold and melted plastics. However, there are other manufacturing methods available such as vacuum forming, compression molding, blow molding, and injection molding. The type of molding process is typically dependent on the intended purpose of the final product. Because of the ability of the plastic molding process to generate products at a fast rate and at close tolerances, it can be used for purposes such as prototyping and mass production.
Benefits of Plastic Molding
Plastic molding comes with numerous advantages. First, the process has a fast turnaround time. The speed may vary depending on the product’s complexity, but, in general, the turnaround time is very short. In addition, the plastic component is often ready as soon as it leaves the mold, and it usually does not need to undergo any further processes, such as surface finishing. The vast majority of plastic molding machines are automated, so they require little to no manual input. As a result, plastic molding machines are safer to use and they keep labor costs down. Plastic molding equipment keeps wastage costs at a minimum. They generate only a small amount of waste with every cycle, and the small amount of waste produced can be easily reused and recycled for other molding processes.
Factors to Consider When Using Plastic Molding
One disadvantage to the plastic molding process is the initial cost of the equipment. The molds and the machinery can cost several thousand dollars. However, both the molds and equipment are engineered to last, and the products they generate are at a low cost. Therefore, there are numerous industries that swear by the plastic molding process. Plastic molding is a highly recommended process for manufacturing products, and its advantages far outweigh its drawbacks.