Study On Machining Characteristics And Comprehensive Performance Evaluation Of Screw Screws

Large-scale thread hard whirling with the features of time variable impact, multi-point variable floating support, and dynamic clamping of hold device will lead to complex dynamic response of the whirling system, which will affect comprehensive performance of the processed ball screw, such as the surface integrity, life, reliability, etc. To realize the optimizing control of the whirling process and improve the quality and comprehensive performance in hard whirling further, the eight-meter CNC whirling machine for large-scale thread was taken as the research object, the physical behavior simulation and dynamic characteristics of the whirling system, and the comprehensive performance evaluation and optimization of the processed ball screw were researched respectively.According to the geometrical forming mechanism of hard whirling, the arc cutting model was established based on ABAQUS, and the cutting force was simulated and tested by the hard whirling experiment. Then the cutting force, temperature field and residual stress were simulated under different cutting parameters, such as cutting speed, maximum instantaneous cutting thickness, and tool rake angle. The second cutting finite element model was established firstly, and the influence of second cutting on the cutting force, temperature field and residual stress was studied.The dynamic model under three-dimensional moving force based on Rayleigh beam theory was established considering the time variable impact and multi-point variable constraint, the vibration response of the lead screw length was researched and tested by the whirling experiment, then the influence on vibration response by the rigidity of holding device, the number, layout and rigidity of floating support was analyzed. Aiming at the minimum system vibration response, the optimal placement of the floating support is studied based on the genetic algorithm.A small-sample accelerated failure evolution test method of ball screw based on full cycle staging step strategy was presented considering high reliability, long life and limited number of test bench, then a accelerated life test was carried out. Multi-objective model for the comprehensive performance of ball screw were built in order to evaluate the comprehensive performance of ball screw objectively and fairly.This paper will contribute to the hard whirling research, life prediction, evaluation and optimization of comprehensive performance for ball screw.