1. Power Source of an Injection Molding Machine

The following three types are the most frequently used power sources of injection molding machines.

1) Hydraulic type

2) Electric motor driven type

3) Hybrid type

The hydraulic type is the one that has been used most often so far ever since the injection molding machine was developed. The mold is opened and closed by the hydraulic pressure of the working fluid supplied by driving a hydraulic pump by an electric motor, thereby operating the mechanism during injection. While this method has advantages such as it is possible to achieve high mold clamping forces relatively easily, it also has drawbacks such as it is difficult to carry out precision control, it is difficult to operate several actuators in parallel at the same time, etc.

The electric motor driven type uses a method of driving using an AC servomotor under computer numerical control (CNC). In this method, it is possible to realize accurate operation with no use of operating oil, and also, it is possible to carry out clean and silent operation. There is also the advantage over the hydraulic type that the running cost is low because the electric power consumption is about 40 to 50% of the hydraulic type. Recently, electric motor driven types with mold clamping forces up to 2000 tons haven been developed, and this method will become the major one from now on at mold clamping forces of 350 tons or less.

The hybrid type is one in which both the hydraulic method and the electric motor driven method driving the machine are used, with the intention of obtaining the advantages of both methods. The general pattern is to make either the injection side or the movable side hydraulic type.

4) Electric Control Device

A control computer is used for carrying out process control for controlling the operation of the injection molding machine and the molding conditions, and for carrying out feedback control using sensor detection, and a control device is used for controlling the screen display, etc. The molding conditions, etc. can be recorded in a computer, and it is also possible to record them in an external computer connected via a LAN, or in an external memory.