The basic manufacturing process of injection molding: plastic is melted in the plastic injection molding machine and then injected into a mold under high pressure. There, the material is cooled, solidified, and afterward released by opening the two halves of the mold. This technique results in a plastic product with a predetermined, fixed form.
To facilitate production, the parts that play a role in the plastic injection molding process must be carefully designed. The products made by plastic injection molding machines are first designed by an industrial engineer or a designer. Then, a mold maker creates the mold – usually from steel or aluminum. This toolmaker takes all essential conditions into account: The material that is used for the end product, the features of the product; but also the material of the mold, and the properties of the plastic injection molding machine.
IM process
Scheme of injection molding process
The process cycle of injection molding itself consists of the following steps:
The mold is placed into the injection molding machine (IMM). The molding machine closes the mold and, thanks to the clamping tools, the mold stays closed during the plastic injection molding.
Read more about clamping and clamping force.
The plastic is fed into the IMM in the form of granules or pellets. The molding machine heats the plastic until it is liquid. The nozzle of the injection molding machine then injects the melted plastic into the mold (injection pressure). The cavity of the mold is now filled with plastic liquid. This will then cool down to form a solid product. Finally, ejectors push the cooled product out of the machine as a finished part. The injection molding process is complete.
