Research On The Method Of Upgrading And Reliability Assessment Of The Machining Center

20 10FP320-2*4M Machining Center is a large-scale precision gantry machining center introduced by Shenyang Blower Group Co.,Ltd.in the 1980s.After decades of use,the electrical and mechanical aspects of the machining center have produced a certain degree of aging and wear.At present,there are some problems in the machining center,such as the decline in geometric accuracy and the backward level of numerical control system.The failure rate and maintenance rate of the equipment are also increasing,and the processing quality and production progress of important parts have been unable to be guaranteed.20 10FP320-2*4M machining center is taken as the research object of the paper.Based on the reliability theory analysis,the method of inspection and repair of the mechanical structure and upgrading the CNC system are studied,and the specific upgrading and transformation are completed,and the reliability and availability of the equipment are improved.The main work of this paper is as follows:(1)On the basis of reviewing relevant literatures domestic and foreign,the research status and latest developments of CNC machine tool upgrade and machine tool reliability research are reviewed,and the main research contents of the paper are determined.(2)Based on the reliability analysis theory,the fault location,fault mode and fault cause of the machining center are analyzed,the weak parts of the machining center are found,and the CNC system upgrade and mechanical maintenance plan of the machining center are determined.(3)In terms of mechanical structure,the entire machining center was comprehensively overhauled.The geometric accuracy of each coordinate axis is detected and adjusted.The research focused on the mechanism of the crawling of the work center table and solved the crawling problem of the workbench.(4)In the aspect of numerical control system,the original system was replaced by Siemens 840D SL numerical control system.The model.of the servo drive and servo motor was determined,and the PLC software control program was designed.According to the specific configuration and requirements of the machining center,the reasonable settings of the numerical control system,servo drive and inverter parameters were realized.(5)Research on the inspection and compensation methods of the transformation and upgrading of the machining center.The positioning accuracy and repeat positioning accuracy of each linear axis were measured by laser interferometer.The positioning accuracy was compensated according to the measurement result,and the pitch compensation and over-quadrant compensation were performed on the machining center.Finally,the precision level reached by the machining center was obtained through experiments.(6)In order to predict the level of reliability after equipment modification and upgrading.A grey GM(1,1)prediction model based on fault interval time is established to predict the time of fault occurrence,so as to improve the protection work and improve the reliability level of the machining center.The paper using the reliability analysis theory finds out the weak parts of the machining center,determines the CNC system upgrade and mechanical maintenance plan of the machining center;improves the mechanical and precision of the machining center's mechanical and numerical control system,and improves the mechanical precision of the machining center;The theory predicts the time of failure,takes necessary measures for possible problems,and improves the reliability of equipment operation.The research work of this paper has an important reference for the transformation and upgrading of similar CNC products.