Injection molding: Process, Maintenance, Advantages, Disadvantages, and Application


The injection molding process may seem simple, but it’s way more complicated than it looks. The process entails adding plastic materials or metal powder through the hopper located at the top of the machine. Then the hopper transfers the plastic into the barrel, where it is heated to a molten form. The molten plastic or metal goes into the mold from the barrel through the nozzle.

There’s a system of runners in the injection mold that spreads the melt from the sprue to the mold that ascertain the dimensions of the molded product. The mold halves clamp together using clamp plates with high pressure from a hydraulic piston.

Holes are drilled on the cavity to keep the mold cold below the solidification range of the plastic. Then the screw moves forward, pushing the melt through the runners into the cavities. Then, the injected molded parts are left to cool and solidify. The injection mold is withdrawn, activating the ejector pins that eject the molded parts out of the mold. The process is mainly automated with computer controls. 

How to Maintain the Parts of the Injection Molding Machine

Maintaining a plastic injection machine should go beyond the surface parts and go deep into the root of the equipment so that the equipment can remain operational and efficient. Maintenance helps reduce errors or defects in the finished molded products.

The mechanical hinge of the clamping unit should be serviced and lubricated adequately; otherwise, the mechanical hinge will have a reduced serviced life span.

The clamping unit shouldn’t be used more than the working pressure. The clamping stroke should be regulated at an adequate position to minimize the pressure on the machine during clamping.

The injection platform’s guide rod should be kept clean and well-lubricated, and the injection platform should be clean and moisture-free. Also, before using any special plastic, the manufacturer should determine if it suits the mold.

The injection machine has to be maintained regularly to avoid costly repairs or producing inferior molded parts.

Injection Molding Advantages:

The following advantages of Injection Molding are:

  • Injection molding has a higher rate of production. The number of parts produced in an hour is enormous. A lot can be made even in a minute.
  • Less wastage of materials
  • Low labor cost
  • Color control is good.
  • It’s a suitable process for producing products with complex and intricate geometries.
  • Enhanced Strength.
  • Finishing requirements are reduced.

Injection Molding Disadvantages:

The following disadvantages of Injection Molding are:

  • High tooling costs and long set-up lead times.
  • Part design restrictions.
  • Setup Cost is also very high.
  • Small runs can prove costly.

Injection Molding Application:

The following application of Injection Molding are:

  • The injection molding process can produce thin-walled plastic housing products, which may need ribs on the interior surfaces.
  • These housings are used in various products like household appliances, power tools, automotive dashboards, and electronics.
  • It also produces many daily-use items, small plastic toys, toothbrushes, and medical devices.

Was it worth reading? Let us know.