Injection Molding

Injection molding is a process that is popular due to its ease and reliability. It is typically used for making parts and components, especially those made of plastic, glass or polymers (thermosetting and thermoplastic).

The material that is used for manufacturing is typically fed through a heated barrel which results in the melting and hence easy molding, giving proper shape to the job. The molten material is forced into a mold which generates the shape and dimensions of the component.

The Basic Steps of Injection Molding

The process of induction molding has three basic steps. Before beginning the process, the proper material and manufacturing conditions must be identified. An overview of the three steps is mentioned below.

  1. Designing the Part or Product- This is the first step of any production process. The design process should be carried out with utmost caution as injection molded parts cannot be altered significantly, they can only be machined for more accurate dimensions. Additionally, depending upon the nature and use of the part, the material for manufacturing must be chosen during the design phase itself.
  • Designing the Mold- The mold is usually created after the design has been finalized and a basic prototype has been built to confirm the overall appearance and “feel” of the product. The mold needs to be accurately designed considering the tolerances. Some of the conventional material which is used for designing molds are:
  • Some of the high precision and expensive molds are made from hardened steel. While this material is expensive, molds made from such steel have an incredibly long life and long-lasting quality which can result in an overall reduction in costs.
  • Pre-hardened steel is often used to make cheap molds which are not meant to last long.
  • Aluminum is used to make single cavity molds which are used for prototype-tooling where the number of parts is not very high. The manufacturing quality of aluminum dies is not very high and is typically used for prototyping.
  • For molds with concentrated shear heat or where fast heat removal is necessary an alloy of beryllium and copper.
  1. Injection of the Mold- After the final design has been approved and the appropriate die has been made, one can begin the manufacturing process. As mentioned above, injection molding is perfect for polymers and as such powdered form of the appropriate is chosen and fed through a hopper. The hopper is connected to a heated barrel which has a screw-feed system. The screw is used to control the gate and provide enough time for cooling before injecting further.

Injection molding is one of the most versatile manufacturing techniques which allows for a variety of complicated shapes and structures. Today with automation technologies robotic injection molding has become quite popular. It uses robotic manipulators to orient the mold and changes components around to attain the desired shape. A mobile robotic system with live sensors which can collect visual feeds is far more agile and efficient than manual injection molding processes.

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