Understanding Injection Molding

Answer 1

When it comes to manufacturing high volumes of plastic parts or components, few processes are more efficient or effective than injection molding. Since being developed in the 1930s, injection molding has become one of the most popular methods of creating plastic parts and pieces. The process, which was inspired by the metal die casting techniques, brings many benefits to the table. By understanding how it works, you can get a clearer idea for why it is so enduringly popular.

The Injection Molding Process

The injection molding process begins with the injection of small resin pellets into an injection molding machine. The machine is made up of two primary components - a clamping unit and an injection unit. Before the process starts, a mold is created that will be used to form the plastic part that is needed. Once the mold has been clamped closed with high pressure, the resin pellets are put into the machine. Colorants are put in along with them, to give the resulting part the appropriate color.

When they are placed in the injection molding machine, the resin pellets fall into its injection unit. The unit is heated up and the resin pellets are melted. The resulting molten plastic material is then injected into the mold, or clamping unit. This is achieved through the use of ramming devices or screws.

At this point in the injection molding process, mechanical or hydraulic pressure is applied to the molten plastic. This is done in order to ensure that every corner of the cavity is filled, so that there are no deformities in the completed part. Following this point, the plastic is allowed to cool. The two halves of the clamping unit are eventually opened and the completed part is ejected with ejecting pins. Any extra pieces, or runners, are trimmed away and recycled.

The Top Benefits of Injection Molding

Injection molding is popular for many reasons. Finishing requirements are minimal; when a piece is complete, little else usually needs to be done to make it usable. Injection molding is also very efficient. The process doesn't generate a lot of waste, since the little scrap that is produced is usually remelted or otherwise recycled. For manufacturers, these benefits translate into savings; in turn, a company's bottom line can be greatly improved. Considering the fact that one injection molding machine - and one mold - can create thousands of identical parts, it's easy to see why the process is so well regarded.