Design And Research Of Testing System For Main Spindle Box Of CNC Lathe Based On LabVIEW

Main spindle box is an important part of CNC Lathe, and its assembly quality will affect the overall performance of CNC Lathe directly. So the main spindle box must be tested. The temperature rise and abnormal sound of bearing are important performance indexes of main spindle box’s assembly quality. At present, the bearing’s temperature rise of HTC20series CNC lathe is measured by testers through the hand-held infrared thermometer in Shenyang machine tool factory, and abnormal sound of bearing is distinguished by testers through ear judgment. This way of testing is labor-intensive and inefficient, and it affects the production schedule. Therefore, it is very necessary to design a set of CNC lathe main spindle box automatic testing system. It will be significative to improve the accuracy and efficiency of main spindle box and reduce the workload of testers.The paper takes the main spindle box of HTC20series CNC lathe as the test object. It adopts sensors, data acquisition card, industrial control computer, frequency converter and so on as hardwares, adopts LabVIEW as software tool and adopts better data analysis methods to develop the main spindle box testing system according to the craft. Main content of the paper is as follows.(1) The paper introduces present development of bearing’s temperature and abnormal sound testing methods, the basic structure of testing system and the work that needs to be done. The paper analyses the basic theories of temperature rise and abnormal sound of bearing including origin and testing methods.(2) According to the requirements, I design the overall plan of testing system, hardware structure and select models of main hardware. The paper expounds threshold analysis method to judge bearing’s temperature rise and amplitude domain and frequency domain analysis methods of vibration to judge the sound of bearing.(3) The paper introduces the concept, advantages and related development technology of LabVIEW and DAQmx. It expounds software structurethe and testing procedures of the system, and designs the programs with modular method. The system has five function modules including landing module, main interface module, craft requirement module, testing principle module and testing module. The LabVIEW program is tested by using simulation signals.The performability of LabVIEW program and the rationality of data analysis methods can be proved in this way.By simulating temperature and abnormal sound signals of bearing to test LabVIEW program, the results show that the temperature rise of bearing can be judged by threshold value analysis method and the abnormal sound can be judged by amplitude domain and frequency domain analysis method. It can meet the requirements of actual production.