Modelling And Acquiring Methods For Fundamental Energy Data Of Machine Tools

Machine tools consume tremendous energy in large quantities and with poor energy efficiency, which implies a great potential for saving energy. Thus, it is important to do some research on the energy consumption and energy efficiency. The energy fundamental data greatly support the research on the energy consumption and energy efficiency. As a result, this paper is constructed to model and acquire the energy fundamental data of machine tools funded by the National Natural Science Foundation of China(Grant No. 51375513) and the National Hi-Tech R&D Program(863)(Grant No. 2014AA041506). The main contents of this paper are concluded as follows:The analysis of the structure of the energy fundamental data. This paper first analyzes the service phases during the service process of machine tools, the energy fundamental data and components existing in those phases. Among those phases, energy consumption in the idle model and no-load model keeps stable and can be expressed by constants. As a consequence, this paper only studies on energy fundamental data of the start-up process and machining process.Research on determining the energy consumption of machine tools in the spindle start-up process before machining. Regularity and the computing model of start-up energy consumption is complicated and of great difficulty to acquire. This paper presents a method for determining start-up energy consumption based on specific databases consisting of data and functions. To use the database, the relative change rate of power is utilized to identify a start-up process, and a relation model between the start-up energy and the spindle speed is established. The energy consumed in the starting process is obtained by summing the energy consumption of each recording interval or by integrating the power function in its time domain depending on the speed shifting mode of the machine tools.Research on acquiring load losses coefficient(LLC) of the main transmission system of machine tools. The cutting energy consumption is able to get by the load losses coefficient of machine tools. Thus, this coefficient becomes the key to efficiently obtain cutting energy consumption. This paper provides a mapping method to acquire LLC of the main transmission system of machine tools. This method firstly choose a machine tool as the standard one; then, by adopting the same cutter to cut a standard work piece with standard parameters, then the mean cutting power value for each cutting parameter is attained; those cutting powers urge the construction of an overall cutting power model of the cutting system; based on this overall cutting model, it is accessible to obtain cutting power of any objective machine tools which machines operate under the same cutting environment conditions; establishing the air-cutting power databases for all the objective machine tools in preparation for the acquisition of LLC; finally, let the objective machine tool works under the same cutting conditions, detecting the input power of its main transmission system and retrieving its air-cutting power and cutting power, the LLC of objective machine tool is acquired.The case study and application study proves that the approaches presented in this paper are able to efficiently and easily acquire the start-up energy consumption and the load losses coefficients with relative small errors. By the supports of the existing idle energy consumption and no-load energy consumption, the entire energy fundamental data are available and are practical for analyzing the energy consumption of machine tools, evaluating the energy efficiency, forecasting energy consumption and planning the energy quota for machining a piece of work in manufacturing.