More and more sectors of the economy use the technology of processing plastics. Knowing the principles of operation and the design of the injection molding machine will allow you to understand how much you can gain by using these machines . Thanks to it, you will receive not only the highest quality products, but also the cost of their creation will be relatively low. Before explaining the principle of operation of the injection molding machine, we will explain what this device is, what its use is, what elements it consists of and what types of them are.

Injection molding machines – an injection molding process

Injection molding machines are multifunctional machines used for the production of plastic parts of various colors, shapes and sizes. With their help, you can produce elements of even a very complex structure. However, one of the greatest advantages of this type of treatment is the high repeatability of the products , which is difficult to achieve using any other manufacturing method. Moreover, the manufactured components are durable and precise . Injection molding machines are plastic processing machines that use an injection molding process. Thanks to it, they can form thermoplastics or thermosets.

The most important advantages of injection molding treatment are:

  • high quality and aesthetics of manufactured products,
  • repeatability of shape and size,
  • the ability to create even very complex shapes with one technical operation,
  • possibility of mass production,
  • low emissions of harmful substances,
  • full process automation,
  • no need for finishing,
  • low production waste.

Application of injection molding machine

Injection molding machines are used in factories and plants where plastic items are produced . This machine is used by a wide variety of industries, including: medicine, automotive, aviation, construction, household appliances, electrical and electronic industries. The plastic injection molding machine allows you to make toys, furniture, fittings, gardening articles, and even very small and specialized elements for control and automation systems.

Construction of an injection molding machine

The injection molding machine is a central unit that consists of three systems. The plasticizing system is responsible for plasticizing the material and forcing the resulting mass into the mold. Its mechanism of action is based on the snail. Another element of the injection molding machine is the closing system . It consists of a single or multi-cavity mold and a special closing system, whose main task is to keep the mold (hot or cold channel) closed when the pressure in it increases. The last part of the plastic processing machine is the drive system , which can be hydraulic or electric. As a result of its actions, the worm is set in a rotary and reciprocating motion, and the movements of the mold and elements forming the detail are performed. Other important elements of the injection molding machine are the control system with a touch screen, the temperature control system, the material container, the mechanical and pneumatic system used to separate the part from the mold.

Types of injection molding machines


There are three types of injection molding machines. You can distinguish:

  • hydraulic injection molding machines – are based on a hydraulic drive. During their operation, the cooling system is extremely important, which ensures the correct operation of the machine. They are chosen because of the low price. Hydraulic injection molding machines are perfect for any industry in which the injection molding process is necessary,
  • Electric injection molding machines – they use digitally controlled servomotors to drive them, which control every process taking place in the injection molding machine (from dosing, plasticizing, injection and pressing, to the movements of the mold and ejector). They allow for greater precision, higher efficiency, lower operating costs and reduce the noise level to 10 dB (A). They also ensure clean production and better working comfort for operating personnel. Many electric injection molding machines are also equipped with additional functions such as e.g. APC – Adaptive Process Control or SocialProduction. Electric injection molding machines are chosen by companies that care about the rational management of resources and the image of a modern enterprise that uses ecological solutions,
  • hybrid injection molding machines – combine the precision and speed of an electric drive with the power and operation of a hydraulic drive. As a result, they achieve remarkable performance at reasonable operating costs.

The principle of operation of the injection molding machine

The operation of the injection molding machine consists of phases that follow one another in a cyclic order . Their task is to plasticize the material and fill the form with it. Processing of the material begins when the mold is open and the cylinder is pulled away. The first stage of material processing is collecting the material from the hopper to the plasticizing system of the injection molding machine . Then, the material in the cylinder becomes plasticized through the friction between the screw coils and the cylinder walls and the regulated cylinder temperature. In addition, in this process, thanks to the special geometry of the screw, the material is mixed and homogenized with dyes and additives. In the next step, a plasticized dose of material in front of the screw head is injected through nozzles into a closed injection mold. The next stage is the cooling of the molded part in the mold . Simultaneously with the cooling of the molded part, the next plasticization process begins in the plasticizing system and the dose is prepared for the next injection. When the detail is at the required stability and temperature, the mold can open. Finished parts, depending on the specificity of the mold and the product, can be removed from the mold by simple ejection or picked up by a robot . After removing the part from the mold, another injection cycle may begin.


Injection molding machines – our offer

Do you want to learn more about injection molding machines? Check out our PTS training courses ! You will find courses on, among other things, the setting and optimization of the injection process or ways to avoid defects in moldings. If you are interested in buying a machine, see the KraussMaffei injection molding machines (including KraussMaffei MX injection molding machines ) available in our offer. We also offer injection molding machine service, and our Research and Development Center for customers develops new products and improves injection molded products. We invite you to familiarize yourself with our offer !