Comprehensive Performance Testing System Development Of High-speed Precision Ball Screws

Ball screws are key function units of CNC machine tools, whose performance directly affects that of CNC machine tools. With the development towards high speed and high precision of CNC machine tools, there are more requirements on the performance indexes of ball screws, such as precision, noise and temperature rise, etc. Therefore, it is of necessity to study the comprehensive performance testing methodology and technology of high speed and high-precision ball screws based on these performance indexes. So far, the performance testing technology of ball screws abroad has been relatively consummate, yet the study in this field at home has a later start and there is still a long way to go. Thus, there will be important theoretical values and real significance to develop comprehensive testing system of high speed and precision ball screws.The dissertation analyzes the demand for comprehensive performance testing system of high speed and precision ball screws, confirms the performance parameters which need to be tested, such as positioning accuracy, noise, temperature rise, vibration, thermal deformation and friction torque, and then a comprehensive performance testing system of high speed precision ball screws is developed. The developed testing system can measure a maximum length of5000mm and the diameter within Φ20～80mm. It can do the high speed dynamic measuring of position accuracy, backlash, noise, temperature rise, vibration, friction torque and the screws’thermal deformation under the load state. The motion control system of the comprehensive testing device of ball screws is also designed and constructed, which adopts the semi-closed control mode with the position and speed combined controlling. Based on the design and selection of the servo system hardware, the hardware connection of motion control system and the creation of the upper and lower computer’s motion control and communication program, various motion patterns of servo motors are controlled by IPC (Industrial Personal Computer). The testing principle and methodology of each performance indexes of ball screws are researched, and the hardware design and the software programming of the data acquisition system of performance indexes, such as position accuracy, backlash, the nut’s temperature, the screws’temperature, the thermal deformation, noise and vibration, are completed. The signal filtering based on wavelet analysis is realized, and the possible electromagnetic interference of the system and the prevention measures are analyzed as well. The comprehensive testing software with a good function is developed based on LabVIEW, which combines each module of the motion control, performance parameter measuring, the instrument calibration and data analysis. The developed software can realize the functions like motion control, curve measuring, data analysis and saving and report generation, etc. in the performance testing process of ball screws. Finally, the developed comprehensive testing system is debugged, and the availability and precision of the system is proved by the performance tests.The current system has a steady running at work site and has met the performance testing requirements of high-speed precision ball screws. It will become a solid foundation of further development of high-speed ball screws.