Design And Study Energy Consumption Detection System For Injection Molding Machine Based On Virtual Instrument

As the injection molding processing becoming more and more important in plastic processing, the injection molding machine has been the most valuable plastic processing machine, which has got extensive used. However, with the sharply development of plastic products industry in recently decades, the serious energy problem of injection molding machine has began increasingly prominent, which became a big obstacle to the further development of the industry.Promoting the research in the field of energy saving and reducing consumption also became the most emergency task of injection molding machine industry.The traditional instruments often got various kinds of inadequate in the testing process for the condition of injection molding machine are certain complexity. This paper had introduced the new concept of virtual instrument, which used high performance computer software technology to partly replace the hardware of traditional instruments. Based on this, an energy detection system has been established. This system could display the energy consumption of the whole injection processes, and of the different processing stages. This system also acquired relative parameters to meet the need of the research in the energy consumption. Due to the outstanding scalability and flexibility, the virtual instruments can greatly reduce the test system costs and realize more powerful functions.This paper first analysed the process and control principle of the injection molding machine, and researched the characteristic of energy consumption in different processing stages of injection molding, then proposed the detection method which acquired the control signal from the injection molding machine control system. Through this method, the instruments and the machine chould share one control source. Thus, the problem to distinguish the different stages of injection processes has been successfully solved. By the on-line integral of different processing stages, the system could detect the whole energy consumption of the machine and the energy distribution of different processes stages in an injection molding cycle.In the design of the hardware, this paper firstly analyse the characteristic of different signal. Then design a converter circuit to acquire the digital signal in control system of the machine, which could obtained the precise time pulse of different processing stages. With a power sensor, the real-time power curve of injection molding machine hydraulic system could also be found.In the design of the software, this paper used LabVIEW—a graphical programming language—as the software development tools. The author introduced the sub-VI of the data acquisition, data processing,data display and storage, especially for the design of the MODBUS communication protocol and the on-line integral procedure.This paper first estimated the error of the energy consumption detection system caused by software, then researched the energy consumption distribution of injection molding machine by using this system. And the distribution of 4 different stages in an injection molding cycle had been found. The single factor experiment was designed in order to analyse the relationship between the different processes parameters and the energy consumption in different processes stages. This paper also analysed the influence of screw parameters to plasticizing energy consumption by the energy detection experiment of 9 different injection screws.