Injection Molding Process

What is injection molding? It's a process that helps shape plastic by melting and injecting it into a mold that has been predesigned. It is the most widely used manufacturing process in the world as it has many advantages compared to the conventional methods. This process was initially based on metal die casting designs. Polythene, nylon and polypropylene are thermoplastic materials that are used in the process.

The clamping and injection units are the two main elements of the injection machine. The process starts with the custom injection mold clamped under pressure to complete the injection and cooling process. Pellets are put in the machine with the right colorants. The pellet resins fall in the injection barrel that is heated to meting point. They are then injected into the mold.

The next step of the process also known as the dwelling phase is when the melted plastic is contained in a mold and pressure is applied to ensure that the cavities in the mold are fixed. The plastic is allowed to cool and then the two halves of the mold are separated. Finally the plastic part is ejected from the mold. The entire process is cyclical and depends on the cooling time.

When you use this process for manufacture, you do not require any post production work as the parts are complete. It is also environment friendly as the plastic waste that is generated is recycled and this ensures that little or no waste is generated in the entire manufacturing process.

Fast and accurate production

Injection molding parts can be found in homes, offices, cars and other dozens of places. A high number of parts can be produced each minute. It mostly depends on how many molds are there in the tool. In most cases it is 15 – 25 seconds for each cycle of production. This enables you to produce a large number of parts in a fast and accurate manner. The high production output makes it cost effective.


The color and material of the parts can be changed without any difficulty. The molded parts offer an unlimited amount of flexibility when it comes to design. You may be able to use more than one material and do not have to worry about using only a specific type of plastic. As the parts are custom made, it reduces the risk of errors significantly.

Low costs and low waste

As the scrap pieces of plastic can be melted and recycled, it leads to very little wastage. The labor costs are also low as the parts can be put on production using the automatic tool that runs on the machine. Full automation of the machine is possible and this can help lower costs of production. The overhead costs are also reduced after automation. It also allows for accurate and precise injection molds.

Although the injection molds are expensive, the quality of the parts may make them insignificant. As it has many advantages over other methods of plastic molding, injection molding is the most preferred choice for manufacturers. It is not just simple and reliable but also efficient.