What is Injection Molding?
Injection molding is a method of producing plastic parts.This is done with an injection molding machine. The shape of the part to be injection molded controlled by the geometry of the injection mold. The injection molding machine has two basic parts; the injection unit, which melts the plastic and then injects or moves it into the mold, and the clamping unit, which holds the injection mold. The unit clamps the mold in a closed position during injection, opens the mold after cooling, and ejects the finished part. Injection molding is a commong method of producing intricate plastic components in high volume. Injection molds are made from hardened tool steel, although aluminum may be used for some low volume applications of injection molding. Injection molds can vary from simple open-shut injection molds, single cavity injection molds to complex multi-cavity injection molds with moving cores, stepped shut-offs, unscrewing devices. Due to the tonnage used in this high pressure process, pro
In injection molding, plastic granules are heated and “injected” under pressure into metal molds, where the molten plastic hardens into a designated shape. The mold then opens and the newly formed part is removed and inspected, ready for shipment or secondary manufacturing operations. Injection molding is an extremely versatile and popular form of molding. Other processes include extrusion, thermoforming, and blow molding.
• Steps to Creating a Plastic Part • The Injection Molding Machine • Injection Molding Screw • Gas-Assisted Injection Molding • Structural Foam Injection Molding • Flow Rate • Colorants • Cost Factors • Mold Materials • Molecular Orientation • Multi-Cavity Molds and Family Molds • Gating • Weld Lines • Shrinkage and Warpage • Cycle Time • Ejecting the Part • Troubleshooting • Summary
In the 1967 film The Graduate, Mr. Robinson offered a single word of career advice to Benjamin Braddock, the character played by Dustin Hoffman: “Plastics.” It would seem that Robinson had the right idea. The industrial science of transforming plastic resins into useful things through the process of injection molding, has had a tremendous impact on industry and on most of our lives. The injection molding process was first designed in the 1930s and was originally based on metal die casting designs. Injection molding offers many advantages to alternative manufacturing methods, including minimal losses from scrap (since scrap pieces can be melted and recycled), and minimal finishing requirements. Injection molding differs from metal die casting in that molten metals can simply be poured; plastic resins must be injected with force. The process uses large injection molding machines, which advance the resins through six major processes to produce everything from computer parts to plastic Hal
Injection molding is a method of producing parts with a heat-melt able plastics material. This is done by the use of an injection molding machine. The shape which is produced is controlled by what is called a “mold.” This is a reverse image of the part desired and can be compared to the familiar “Jell-O” mold. The injection molding machine has two basic parts; the injection unit, which melts the plastic and then injects or moves it into the mold, and the clamping unit, which holds the mold. The unit clamps the mold in a closed position during injection, opens the mold after cooling, and ejects the finished part. Injection molding is a relatively new method of producing parts. The first injection molding machines were manufactured and made available in the early 1930s, while other manufacturing methods you may be familiar with date their origins back over 100 years.
