injection molding pressure and speed

◆ injection molding pressure

This is the pressure that causes plastic flow, which can be measured by sensors that can be used on the mouth or hydraulic line. It does not have a fixed value, and the more difficult it is to fill the mold, the increase in injection molding pressure. The pressure of injection lines is directly related to the injection molding pressure.

◆ The first stage of pressure and the second stage of pressure

In the filling phase of the injection cycle, heating pressure may be used to maintain the injection speed at the requirements level. After the mold is filled, high pressure is no longer needed. However, when some semi -crystalline thermoplastic plastics (such as PA and POM) are injected, due to sudden changes in pressure, the structure will deteriorate, so sometimes there is no need to use secondary pressure.

◆ Model locking pressure

In order to combat the injection pressure, the mold locking pressure must be used, and the maximum value that can be used automatically should be automatically selected. Instead, the projection area must be considered and a suitable value is calculated. The projection area of injection plastic parts is the maximum area seen from the application direction of the model. For most injection, it is about 2 tons per square inch, or 31 trillion Newton per square meter. However, this is just a low value, and it should be used as a very rough experience value, because once the injection molding part has any depth, the side wall must be considered.

◆ Back pressure

This is the pressure that needs to be produced and surpassed before the screw is exired. Although high -back pressure is conducive to the uniform spread and plastic melting, it also extends the back time of the screw in the middle of the screw The stress of the injection molding machine; the lower the back pressure, the better, and in any case, it cannot exceed 20%of the injection molding pressure (maximum quota).

◆ Together pressure

The pressure of the mouth is the pressure in the mouth. It is about the pressure of plastic flow. It does not have a fixed value, but increases with the difficulty of filling the mold. There is a direct relationship between the mouth pressure, line pressure and injection pressure. On the spiral injection molding machine, the pressure of the shooting mouth is about 10 % less than about 10 % less than the injection pressure. The pressure loss can reach about 10 % when the piston injection machine. The pressure loss can reach 50 % during the piston injection machine.

◆ Injection speed

This refers to the filling speed of the mold when the screw is a punch. When injection molding thin -walled products, the high rate of fire must be used in order to facilitate the filled mold when the melting glue is not solidified, and the production is smoother surface. When filling, use a series of programmatic firing to avoid defects such as jet or difficulty. The injection can be performed under the open or closed control system.

Regardless of the use of the injection speed, the speed value must be recorded on the record table with the injection time. The injection time refers to the time for the predetermined in the predetermined in the screw time.