The Application of 6810S Asynchronous Servo for Injection Molding in the Energy-saving Transformation of Injection Molding Machine

For the plastic products industry, power consumption is the main part of its production cost, and the injection molding machine is one of the main energy consumption equipment of the plastic products factory. The energy consumption of the injection molding machine has become an effective way for the injection molding industry to reduce costs and improve product competitiveness. .

I. Overview
The shortage of electricity supply in China has continued for several years, and it is now more severe. The demand for electricity has been driven by the rapid growth of GDP and continues to grow at a high speed. High and low" features. The increase in power supply capacity is limited, and there is a continuous shortage of power supply, which leads to tension between power supply and demand, and the scope of power shortage and areas with continued power shortage are further expanded.
For the plastic products industry, power consumption is the main part of its production cost, and the injection molding machine is one of the main energy consumption equipment of the plastic products factory. The energy consumption of the injection molding machine has become an effective way for the injection molding industry to reduce costs and improve product competitiveness. .
At present, most injection molding machines belong to hydraulic transmission injection molding machines. The power in the hydraulic transmission system is provided by the oil pump driven by the motor. Changes in the injection molding cycle, the flow and pressure required by the injection molding machine in different processes are different, and the flow and pressure required for different processes must be adjusted by the flow valve and the pressure valve, and the load varies greatly, because the quantitative pump is not adjustable Output power, so excess energy can only be consumed in the baffle, oil leakage, oil temperature rise, aggravating the wear of various valves, and causing excessive oil temperature, excessive motor noise, and shortened mechanical life, etc. phenomenon. And the capacity of the design motor is usually much higher than the actual need, and there is a phenomenon of "large horse-drawn cart", which causes a waste of the amount of electric energy. Therefore, energy-saving transformation of injection molding machines is of great significance for reducing energy costs and improving competitiveness.

2. Working principle
  Plastic injection molding is the use of three states (solid-liquid-solid), with the help of injection molding machines and molds to form the required plastic products. Although all injection molding machines are different, the workflow of injection molding machines is basically the same. As shown in Figure 1, it can be roughly divided into seven processes: clamping, injection, holding pressure, melting plastic, cooling, mold opening, thimble (thimble in, thimble retreat, ejection seat retreat) and so on. The completion of each action has a subtle combination of several parameters such as time, pressure, speed, position, etc., that is to say, the displacement at a certain position has corresponding pressure and speed, and the pressure and pressure at different positions and times The speed is variable. At the same time, after each action is completed, a termination signal is sent to the program controller, and the program controller sends a command to execute the next action after receiving the signal. Each process requires a different working pressure and flow rate. In addition to the high pressure required for high-pressure mold clamping, injection molding and melt-dissolving, other processes work at very small pressures. The pressure and flow rate depend on the pressure proportional valve and The flow proportional valve can be adjusted, and the pressure and flow can be controlled by adjusting the opening of the pressure proportional valve and the flow proportional valve.