Plastic Injection Molding

Plastic injection molding is a process in which parts are manufactured using thermoplastic and thermosetting materials, either for a prototype or mass production. This molding process creates products used everyday on both commercial and industrial levels in a fast, efficient manner at low cost.

Plastic Injection Molding Service Providers

  • TNT Marketing: offering a range of industrial services, including printed circuit boards, sheet metal fabrication, and plastic injection molding. TNT Marketing works with many industries, including aerospace, medical, military, and other industrial markets.
  • Diversified Plastics: provides custom plastic injection molded parts and components for a wide range of industries. Diversified Plastics offers overmolding, injection molding, and other custom plastic molding services to deliver parts that will match customers’ exact design specifications.
  • Stack Plastics: is a custom injection molding company offering quality controlled precision molding services to provide top-of-the-line products. Innovative molding techniques and expertise with a variety of available injection molding materials has led to satisfied customers for over 15 years.
  • El-Com System Solutions offers custom plastic injection molding services including insert molding, overmolding, 2D and 3D CAD molding, ultrasonic welding, and hot stamping. They work with a variety of materials and have both domestic and offshore manufacturing capabilities.
  • Le Sueur Incorporated offers plastic injection molding services including two-shot overmolding, insert molding, tooling, and value-added services.  The company also offers in-house engineering support and is ISO 9001:2015 certified.

Plastic Injection Molding Process

In plastic injection molding, a plastic material is heated, and the molten plastic is forged into a mold where it hardens into the shape of the mold. The molten plastic is pushed through the heated barrel by a screw plunger, and the mold itself is kept cool so that the plastic cools quickly and hardens almost as soon as the mold is filled.

The molds for plastic injection molding are usually made of metal. Both aluminum and steel are preferred metals for plastic injection molding molds. The molds are custom designed to spec and are manufactured through a machining process. Plastic injection molding can product parts of nearly any shape; however, the mold design must allow for draft walls to allow ejection of the completed part. For some complex parts this can complicate the tooling.

Plastic Injection Molding Advantages and Disadvantages

Plastic injection molding is one of the most common manufacturing processes in use today, with numerous advantages that are limited only by the properties of the plastic molded. The set-up cost for plastic injection molding can, however, be expensive, making plastic injection molding most common for mid to high volume production runs.

Other advantages of plastic injection molding include the low per part cost on high volume production runs, high material usage resulting in very little loss as scrap, and low labor costs involved in the process. Disadvantages include the set-up costs, and the equipment used for plastic injection molding tends to be very expensive as well.

Plastics Used in Plastic Injection Molding

A wide array of plastics can be used for plastic injection molding. There are over 20,000 different types of plastic that can be used for injection molding, most of which are blends of existing plastic types. The choice of plastic depends on the properties required in the finished part. Some examples of plastics that can be injection molded include:

  • Nylon
  • Epoxy
  • Phenolic
  • Acrylic
  • Teflon
  • PVS
  • ABS
  • Polycarbonate
  • Polyethylene
  • Polystyrene

Plastic Injection Molded Parts

Plastic injection molding is such a common manufacturing process that most people come into contact with plastic injection molded parts literally every day. Some examples of common plastic injection molded parts include: bottle caps, combs, knobs, pulleys, brackets, gears, car dashboards and even entire car panels.

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