Analysis and Research on the energy-saving power d

2022-10-18
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Analysis and Research on energy-saving power drive system of injection molding machine

injection molding machine is an important plastic machine. The focus of energy-saving of injection molding machine is to improve the efficiency of the power drive system itself and achieve adaptive adjustment and matching between the output power of the drive system and the Executive power of the actuator. The higher the energy utilization rate between the two, the higher the energy-saving rate of the system

injection molding power drive system generally has the following three types: hydraulic drive system; Full electronic drive system; Hydraulic electric hybrid drive system. Hydraulic drive system is a widely used power drive system of injection molding machine, and it is the key research object of energy-saving power drive system

first, energy-saving hydraulic drive control system

1. Dual proportional control and quantitative pump energy-saving control system

dual proportional control of flow proportional and pressure proportional control energy-saving technology is developed with the development of injection molding technology and the improvement of control performance. The power drive system composed of on-off valve and quantitative pump can no longer meet the requirements of injection molding performance, but the use of proportional valve can achieve stepless and flexible adjustment to achieve the purpose of effective energy saving. In the process of popularization and application, its energy-saving performance has been continuously improved. The p/q composite electro-hydraulic proportional technology of small and medium-sized injection molding machines and quantitative pump constitute an energy-saving power drive system, which is widely used by domestic injection molding machine manufacturers. The hydraulic pump source of small and medium-sized injection molding machines is generally single pump or double pump, and the discharge flow of the hydraulic pump is adjusted proportionally through the p/q valve. The automatic control technology of the injection molding machine and the performance of the injection molding machine are improved. Under the condition of long cooling time in product molding, energy saving is obvious. It has certain advantages in energy saving and cost performance. Almost all domestic injection molding machines use p/q composite electro-hydraulic proportional technology

the hydraulic pump source of large injection molding machine is composed of multiple quantitative pumps to achieve the flow required by the system. How to match multi pump and proportional valve is directly related to the energy consumption of the system. There are two ways to match multi pump and proportional valve: one is to use p/q3 of small and medium-sized injection molding machines, which is to strive to improve the level of green development. The other is to form an energy-saving power drive system composed of composite electro-hydraulic proportional technology and quantitative pump. The other is to regulate the speed of one small flow pump in proportion, and the flow of the other pumps is superimposed according to the combination of working conditions and the flow of the small pump with proportional speed regulation, forming a flow proportional slash, The flow required for each working condition can be selected on the proportional ramp. This proportional flow speed regulation, except for the small pump with proportional speed regulation, the working flow of other pumps enters the system without the energy loss of the first matching form, which improves the energy utilization rate

2. Application of energy-saving load sensitive control system in injection molding machine

the most effective measure for energy saving of injection molding machine is the adaptive adjustment and matching of flow between power mechanism and actuator. Load sensitive proportional pump energy-saving hydraulic system, the hydraulic power output is synchronized with the load, and its difference reaches the minimum. Basically, there is no energy waste. Compared with the quantitative system, the energy saving reaches%, which is an ideal energy-saving hydraulic system

the set output flow of the load sensitive pump may not match the flow that needs to be accurately adjusted, and the flow regulating valve must be added in the system, resulting in the loss of throttling energy consumption. The closed-loop control system composed of load sensitive pump and servo valve can eliminate the energy loss of throttling and pipeline, and greatly improve the performance of the whole machine. Most domestic units, only from the perspective of energy saving, use load sensitive pump to replace quantitative pump and p/q double proportional valve, without further considering that load sensitive pump can improve the performance of the whole machine, the control performance and energy-saving characteristics of the system have not been further developed. The internationally advanced load sensitive pump control system is equipped with a servo valve in the plasticizing injection oil circuit. The purpose is to form a high-performance closed-loop energy-saving control system with the load sensitive pump to improve the injection performance while saving energy

China has done a lot of work for the research and development of load sensitive pumps. Shaanxi Qinchuan machine tool factory and Shanghai No.1 plastic machinery factory jointly developed a load sensitive pump, which has been successfully applied in injection molding machines. In recent years, Chongqing Bangzhu Industry Co., Ltd. has developed BK series of load sensitive proportional pumps for injection molding machines. The price is about the same as the total price of quantitative pumps and p/q valves, which fundamentally solves the obstacle of high price and difficult promotion of load sensitive proportional pumps. They have been applied in batches and achieved good results

3. The electro-hydraulic energy-saving control system of quantitative pump and variable-frequency speed regulation motor

variable-frequency regulation technology makes the performance of the power mechanism similar to that of the proportional pump energy-saving system by adjusting the speed of the hydraulic pump, so as to achieve the output flow of the power mechanism. General mechanical parts not only cause failure when they are broken, but also match the flow of the actuator, so that the loss of flow. 2. The loss of characteristics after transformation is reduced. The traditional quantitative pump is transformed into a variable-frequency variable drive system, so that the return oil flow of the overflow valve is minimized without high-pressure throttling energy loss, and then the traditional "energy consuming" injection molding machine with high-pressure throttling is upgraded to an "energy-saving" injection molding machine without high-pressure throttling. In addition to the main features of energy-saving functions, the energy-saving injection molding machine also has the following advantages: reducing the impact of mold opening and locking, and extending the service life of machinery and molds; Extend the service life of oil circuit system (sealing components, etc.), reduce the number of maintenance and save maintenance costs; Reduce noise and improve working environment; The oil temperature of the system is greatly reduced, and the cooling water consumption can be saved by more than 30%; It has many kinds of protection for the motor, such as over-voltage, over-current and short circuit. Cixi City, Zhejiang Province, has vigorously promoted the energy-saving technology of injection molding machines since last year. After installing frequency conversion energy-saving devices on injection molding machines, the energy-saving effect of single machines has reached 30% - 60%. After more than 200 enterprises in Cixi installed energy-saving devices for injection molding machines, the annual power savings reached about 60million kwh. The frequency conversion energy-saving control system of injection molding machine produced by Shenzhen Aoyu Control System Co., Ltd. has an average power saving rate of 45% for the oil pump motor

4. High response AC servo motor driven quantitative pump system

high response AC servo motor driven quantitative pump system is an advanced high-performance energy-saving system developed in recent years

the servo motor drive system, because the servo motor does not use the permanent magnet structure, and because of the torque and the cooperation of the rotor with low inertia, it eliminates the pulsating torque, and has good acceleration and deceleration dynamic response characteristics in the speed range. Because the torque is generated by inductive current, the speed changes with the flow demand of the system, and the reaction speed is four thousandths of a second faster than that of the servo valve. The hydraulic system basically does not need cooling water. For products with long pressure maintaining and cooling time, energy saving can reach 80%. Set the speed of the motor to control the flow, and there is no overflow loss. It can greatly reduce the flow loss under pressure maintaining condition and idling condition (waiting period). When maintaining pressure, the motor is in a stopped state, which is more energy-saving than the load sensitive pump energy-saving drive system. The closed-loop control system composed of high response AC servo motor driven quantitative pump system and servo valve can give full play to the energy-saving characteristics and improve the precision control performance of the system. According to Rijin Precision Co., Ltd., the Longheng nc-220 Ⅱ injection molding machine with ordinary motor-driven quantitative pump consumes 20kw/h of power consumption, and the load sensitive pump drive system consumes 10kw/h, saving 50% of energy. The full electric drive system consumes 3.2kw/h, saving 84% energy, and the servo motor drive system consumes 4kw/h, saving 80%. In 2006, Nissei exhibited the "x pump" injection molding machine, which integrates servo motor drive and variable displacement pump in Chicago, the United States. The X pump is the core component of the new fnx ecoproject. The X pump can make it comparable with the all electric machine. The X pump has energy-saving effect. The energy used by Nissei's "x pump" fnx injection molding machine is only about 30% of the company's standard injection molding machine, and the fnx injection molding machine uses 41% less hydraulic oil. The speed and accuracy of X pump are very high, and it can even change direction immediately. The heating rate of injection molding is 45 milliseconds, which is the same as that of all electric machines. The injection speed can be as high as 300 mm per second, twice that of other injection molding machines of the company. The htfwl/j5 servo energy-saving injection molding machine series developed by Ningbo Haitian with htfw as the design platform is equipped with a high-performance servo variable speed power control system to adjust the corresponding frequency output for different pressure flows during the molding process of the injection molding machine, forming an accurate closed-loop control of the pressure flow, realizing the automatic matching and adjustment of the servo motor to the energy demand of the injection molding machine, which can save 40% - 80% of the power

second, electro-hydraulic hybrid drive energy-saving system

due to its excellent performance, the application and promotion speed of electro-hydraulic hybrid drive energy-saving system in injection molding machine is fast. The hylectric series hybrid injection molding machine launched by Husky company adopts variable displacement oil pump and water-cooled motor to form an energy-saving system. The standard auxiliary accumulator system can be equipped with mold closing at the same time of material plasticization, so as to shorten the cycle. Engel company actively develops and combines the accuracy achieved by the full electric injection molding machine with the lower cost hydraulic mold locking mechanism, and develops the victory electric series injection molding machine with increased accuracy and more energy saving. Synergy hybrid injection machine developed by Netstal company is particularly suitable for processing thin-walled and high-tech plastic parts. Synergy hybrid injection molding machine adopts synergy hybrid injection molding machine that directly drives the injection screw. Its accuracy can be compared with that of fully electric injection molding machine, while maintaining high control accuracy, so as to save energy. Italian BMB company designed a new type of elepack series injection molding machine driven by hydraulic electric hybrid. In the injection stage, a hydraulic system equipped with dynamic hydraulic oil accumulator is used to control the injection speed and injection quality, while the ejection of products and the plasticization of materials are driven by motors to save energy and shorten the molding cycle. Muge adopts the technology of power shottm injection system to jointly develop a new hybrid injection molding machine with Ube Machinery Group in Japan. The machine performance is faster, more compact and more powerful than the traditional hydraulic injection molding machine. Compared with similar products, Y-series electro-hydraulic hybrid injection molding machine, the first domestic "super energy-saving injection molding machine" independently developed by Guangdong Hongli Machinery Co., Ltd., has many advantages, such as precision and high mold adaptability. Among them, it has outstanding advantages in energy saving, which can save 70% energy compared with conventional products. It is also at an advanced level among its peers in the world

III. all electric drive energy-saving system

energy saving is a major advantage of all electric drive system injection molding machine. The energy saving of the electric injection molding machine is the energy saving under the injection condition reflected by the high-speed response, which does not affect the productivity. The energy utilization rate reaches more than 95%, which is 25% - 60% more energy-saving than the hydraulic injection molding machine

water saving. Since no hydraulic oil is used and the cooling water is only used for the feeding port, it is planned to be completed by 2030. Therefore, compared with the hydraulic injection molding machine with load sensitive pump, the cooling water can be reduced by 70%, and compared with the hydraulic injection molding machine with ordinary constant displacement pump, the cooling water can be reduced by 90%

high energy-saving injection molding with high performance is the key to the popularization and application of all electric drive system. It has the advantages of high speed, high efficiency and precision. Because the plasticizing injection part adopts a special servo motor, it has a high response speed to the control of injection parameters such as plasticizing speed, back pressure, injection speed and injection pressure

the development of injection molding machine with full electric drive system should be based on high-tech precision injection molding and meet the processing of top products. In order to conform to the workpiece

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