With the development of plastic products from civil to industry, agriculture, national defense, transportation and other industries, the market puts forward higher requirements for injection molding equipment and technology: high speed, high efficiency, energy saving and production automation. This kind of market demand promotes the continuous innovation of traditional injection molding equipment and molding process. The hydraulic electric hybrid injection molding machine is a new product developed in this development direction. In order to explore the hydro electric hybrid injection molding machine, we must first understand the traditional hydro mechanical injection molding machine and the new all electric injection molding machine.
Hydraulic injection molding machine
Generally speaking, the injection molding process is composed of pre plasticization, mold closing, injection device moving forward, injection, pressure maintaining, injection device reset, product cooling and mold opening, product ejection and other actions. The traditional plastic injection molding machine is mainly composed of plastic injection system, mold closing system, hydraulic transmission system and electrical control system, among which the hydraulic transmission system is the power system to ensure that the injection molding machine can work accurately and effectively according to the predetermined process requirements (such as pressure, speed, temperature, time, etc.) and the action procedures in the molding cycle Unification.
The hydraulic system of injection molding machine is mainly composed of hydraulic pump, hydraulic motor, hydraulic control valve, hydraulic auxiliary components, etc.
All electric injection molding machine
The electric injection molding machine uses the AC servo motor to replace the hydraulic driving cylinder in the traditional injection molding machine, equipped with ball (column) screw rod, tooth belt and gear to complete the driving of the machine actuator. The biggest difference between the electric injection molding machine and the hydraulic driven injection molding machine is that the former does not have any hydraulic system, so there is no oil leakage problem, and the production environment is clean; in addition, the advantages of the electric injection molding machine are energy saving and high processing accuracy. The electric injection molding machine uses servo motor to replace the hydraulic cylinder in the common injection molding machine, and realizes the action completed by the hydraulic system, so it does not need any hydraulic power device.
Compared with the common hydraulic injection molding machine, the electric injection molding machine has the following characteristics:
1. High injection accuracy and repeatability. Because the electric injection molding machine uses servo motor to drive the actuator and the microcomputer control system to control each process link accurately, the precision and repetition precision of the injection molding are greatly improved.
2. Short production cycle. Because the electric injection molding machine is composed of several independent servo motors to complete the process of mold closing, injection, pressure maintaining, plasticizing and ejection, compared with the traditional injection molding machine which only uses one hydraulic system to complete the above actions one by one, its injection molding cycle is greatly shortened. The fastest cycle time of high-speed hydraulic injection molding machine is 5.8S, and that of standard electric injection molding machine is 4.8s.
3. Save energy. Ordinary hydraulic injection molding machine in the molding operation without the need of mold locking pressure and injection pressure, the hydraulic oil pump is still running continuously, while the drive motor of electric injection molding machine only operates when the actuator acts, and can save the cooling system of the hydraulic device, so it can save electric energy.
4. Small floor area and low operation noise.
In order to achieve high control accuracy, servo motor is often used as the driving motor of the electric injection molding machine. Sometimes, in order to reduce the cost of the machine, some driving parts that have little influence on the quality of the molded products and have low control accuracy requirements are replaced by other types of motors, such as the driving motors for mold adjustment and injection base movement are selected as ordinary motors or variable-frequency motors.
Hydraulic electric hybrid injection molding machine
Although the all electric injection molding machine has many advantages compared with the traditional hydraulic injection molding machine, it also has its limitations, such as the high cost, especially in the case of large tonnage clamping force, the machine cost is almost unbearable to customers, and the energy transmission under the condition of high speed, high pressure and high precision is not superior to the hydraulic system. Therefore, many smart manufacturers adopt the strategy of complementary advantages to develop the hydraulic electric hybrid injection molding machine so as to provide users with a new injection molding machine with high cost performance based on the advantages of traditional hydraulic injection molding machine and all electric injection molding machine.
The hydraulic electric hybrid injection molding machine not only has the advantages of all electric injection molding machine, but also retains the performance of the hydraulic mechanical injection molding machine. In order to reduce manufacturing cost and maintain large tonnage of mold closing force, hybrid injection molding machine usually adopts hydraulic system to open and close the mold and provide mold locking force, while the plasticizing and injection actions are completed by servo motor. In this way, the lower manufacturing cost and higher injection accuracy can be achieved under the condition of providing larger clamping force; while the hydraulic system only undertakes the clamping and locking action, so it can unload in other stages of the injection cycle to save energy.