Expressed by the maximum injection volume of the machine, the unit is cubic centimeters; the maximum injection volume indicated by the general equipment manufacturer is the theoretical maximum injection volume. The actual machine manufacturing and use process deviations make the actual maximum injection volume of the machine and the maximum The theoretical injection volume has a certain deviation;

The theoretical injection volume refers to the maximum plasticized melt volume (cm3) that the injection device can push out by the screw (plunger) in the injection molding machine in a maximum stroke. The theoretical injection volume is the main performance parameter of the injection molding machine. From this parameter, the processing capacity of the injection molding machine can be known, so as to determine the maximum quality of a plastic injection molded product.

According to the national standard GB/T 12783-1991, the theoretical injection volume is expressed by mass (g) or volume (cm3) in the molten state of the material. There are many ways to mark volume (cm3) in China and the world, because the volume of the material has nothing to do with the density of the material in the molten state, this marking method is suitable for any plastic measurement.

The theoretical injection volume calculation formula is:

Where QL——theoretical injection volume, cm3;

D——screw (plunger) diameter, cm;

S——Maximum stroke of screw (plunger), cm.

Because there is a mutual movement assembly gap between the outer diameter of the screw (plunger) and the inner diameter of the barrel, when the screw (plunger) pushes the melt forward, it is affected by resistance such as the reduction of the nozzle diameter and the friction between the material and the inner wall of the barrel. , A part of the material will flow back from the gap. In addition, there will be a certain amount of shrinkage that needs to be supplemented when the melt is cooled. Therefore, the actual injection volume of the injection molding machine should be less than the theoretical injection volume, and the calculation needs to be corrected by the coefficient K value, the size of the K value and the structure and parameters of the screw (plunger), the outer diameter and the gap, the size of the injection force, and the melt Factors such as flow rate, back pressure, mold structure, product shape, and plastic properties are related. When the screw head has a check valve, the K value is 0.9; if only the reflux of the melt is considered, the K value is 0.97.

That is the actual injection volume:

If you know the quality of plastic products, when choosing an injection molding machine, the volume of the plastic in the molten state is converted to density. which is

Where Qs——the actual injection volume of the injection molding machine, g;

ρr——The density of the plastic in the molten state, g/cm3.

The density of plastics under different temperature conditions is shown in Table 1.

Table 1 Density of plastic under different temperature conditions:

If the model of injection molding machine is selected according to the quality of a single piece of plastic products (note: the quality of a single piece of plastic products should be 70% to 90% of the theoretical injection volume of the injection molding machine), it is best to choose this model of injection molding machine to produce this plastic product. Best plan. If the quality of the plastic product is less than 40% of the theoretical injection volume of the injection molding machine, using this injection molding machine to produce the plastic product will not only reduce the equipment utilization of the injection molding machine, but also greatly increase the production cost of the plastic product.

2. Expressed by the maximum clamping force of the machine, the popular unit is ton;

In addition to the above two most important parameters, the size of the equipment template is also an important parameter of the equipment;

The basic structure of rubber injection machine:

1. Plasticizing injection unit: The plasticizing injection unit is the core part of the rubber injection machine, which plays a decisive role in scorching, air entrainment, density uniformity and the convenience of replacing the rubber material.

2. Mold clamping device: The mold clamping unit is the main part of the rubber injection machine, which plays a key role in vulcanization quality, output efficiency, and convenient operation.

3. Control system: The control system is the brain of the rubber injection machine, which plays a decisive role in the precision, stability and energy consumption of the machine;

4. Safety protection: safety protection is an essential part of the rubber injection machine, which guarantees safe production. The safety protection design mainly considers the safety protection device of the adjustment equipment and the humanization of the production process from various perspectives such as worker convenience, efficiency, and habit, and clear guidelines to consolidate the foundation of production and development.