Explanation of basic knowledge about injection molding

Injection molding machines are special machines for the manufacture of plastic products, which are used to manufacture various plastic parts in automotive, medical, consumer and industrial applications. Injection molding is a popular technique because of the following five reasons:

1. Ability to increase productivity;

2. Both simple and complex shapes can be made;

3. Very low error;

4. A variety of materials can be used;

5. Lower raw material cost and labor cost.

The injection molding machine uses plastic resin and molds to complete injection molding. The machine is mainly divided into two parts:

Clamping device-keep the mold closed under pressure;

Injection device-melting plastic resin and ramming the molten plastic into the mold.

Of course, the machines are also available in different sizes, optimized to produce parts of various sizes, and are characterized by the clamping force that the injection molding machine can generate.

The mold is usually made of aluminum or steel, but other materials are also possible. It is divided into two halves, and its shape is precisely machined into the metal. The mold may be very simple and cheap, or it may be very complex and expensive. The complexity is directly proportional to the part configuration and the number of parts in each mold.

Thermoplastic resin is in pellet form and is the most commonly used material type in injection molding. There are many types of thermoplastic resins with a wide range of material properties and suitable for a variety of product applications. Polypropylene, polycarbonate and polystyrene are examples of commonly used resins. In addition to the wide selection of materials provided by thermoplastics, they are also recyclable, versatile and easy to melt processing.

The molding process carried out in the injection molding machine consists of six basic steps:

1. Clamping-the clamping device of the machine presses the two halves of the mold together;

2. Injection-the molten plastic from the injection unit of the machine is knocked into the mold;

3. Pressure keeping-the molten plastic injected into the mold is under pressure to ensure that all areas of the part are filled with plastic;

4. Cooling-allow the hot plastic to cool into the final part shape while still in the mold;

5. Mold opening-the clamping device of the machine separates the mold and divides it into two halves;

6. Ejection-the finished product is ejected from the mold.

Injection molding is a great technology that can be mass-produced. However, it is also useful for prototypes for initial product design or for consumer or product testing. Almost all plastic parts can be produced by injection molding, and its application fields are unlimited, providing manufacturers with a cost-effective method to produce various plastic parts.

Post time: Apr-12-2021