Research On Circle Forming Process And Roundness Error Optimization In Shaft Journal Cylindrical Plunge Grinding

Shaft journal roundness error has a direct and crucial influence on the rotation precision of hydrostatic spindles.Since hydrostatic spindles are often used as the core component in ultra-precision machine tools,the spindle rotation accuracy directly determines workpieces accuracy.To achieve high-precision shaft journal,grinding is an important method,and plunge grinding is the basis of the journal grinding.Hence,there is great engineering significance to study the circle forming process and roundness error optimization in the journal plunge grinding.At present,most of the journal plunge grinding researches only focus on grinding processing procedure,which cannot reflect the influence of the grinding system dynamic characteristics on the external cylindrical grinding process.A new problem needs to be solved urgently,how to analyze the plunge grinding process and optimize roundness error by combining the grinding system dynamics with the grinding processing procedure.The main research work of this article is as follows:(1)A dual rotor coupling model for journal plunge grinding is established;an iterative algorithm of "grinding force-transient grinding depth" is proposed.The coupling relations of the grinding wheel feed and wear,the workpiece material removal,the grinding wheel and the workpiece vibration displacement and contact deformation is analyzed.A dynamic grinding process system model considers the grinding wheel spindle rotation accuracy and the workpiece initial shape error is proposed.Based on the Newmark-? algorithm,the quantitative simulation of the material removal and journal profile change process is realized.(2)The profile formation mechanism of the journal plunge grinding is revealed.Using the dual-rotor coupling model and the iterative algorithm,considering the influence of the system dynamics and the processing procedure,for a given grinding system and processing parameters,the journal plunge grinding transition process is simulated,which reveals the profile formation mechanism of the journal plunge grinding.(3)The influence rules of grinding machine system parameters and grinding processing parameters on the journal plunge grinding roundness error are studied.The results show that the degree of journal roundness can be reduced by decreasing the amplitude of workpiece rotation error.When the grinding allowance is large enough,the degree of workpiece balance precision has little effect on the roundness error of journal.(4)Roundness error optimization examples of the journal plunge grinding are presented from both aspects of grinding system parameters and grinding processing parameters,and a simulation analysis software for the journal plunge grinding transition process is developed.(5)A test rig for the journal plunge grinding is built,and the roundness error of journal plunge grinding is generated experimentally.The simulation results of the journal roundness error are in good agreement with the experimental results,which verifies the simulation results in this research.The work in this paper reveals the formation mechanism of the journal profile in cylindrical plunge grinding,and provides theoretical guidance for optimizing the roundness error of the journal,which has reference value for improving the machining accuracy of the machine tool.