Papers by Author: Zhan Qi Hu

Abstract: In order to solve the key technical problem in maintenance and repairing of heavy CNC machine tools, the concept of precision reliability and its forecasting module are proposed. The method is especially used for researching of reliability of heavy machine tools of which the samples are not enough for statistical methods. Firstly, spatial error module is established for a type of super heavy mill &boring machine tool based on multy-body kinematics. Then, the effect of wearing amount of kinematic pair of machine tools on machining precision is researched. Therefore forecasting modules for maintenance period and premature wearing of heavy CNC machine tools are built up. The method proposed can be used in calculating for maintenance period of heavy machine tools, analyzing for source of machining errors, and optimal design for total life of CNC machine tools. It can also be used in research of reliability for similar product of single piece or small batch.

Abstract: Analysis of BTA deep hole drilling bar on Liquid-Solid Coupled Vibration model, there are vortex and unstability on bending deformation of the rotating boring drilling bar induced by cutting fluid force. At first, the rotating fluid force inside the boring bar was expressed linear physical form, and it’s stiffness and damping coefficients were derived by the unsteady reynolds dynamic equation of the fluid. Then establish conditions including eddy and mechanical mechanism of the boring bar by cutting fluid force. The results of analysis show that the solution on coupled vibration model are more accurate than the other vibration model. Coriolis effect is the main reason for eddy or unstability of the deep hole boring bar induced by cutting fluid internal the drilling bar’s wall. Some rules are also derived with which cutting parameters can be selected reasonably, which is coincide with the parameters used in heavy machine building industry.

Abstract: In view of the special characteristics of cams grinding, some key technologies of grinding force adaptive control system are researched, including selection of inspecting parameter, modeling of grinding feed system, and design of controller. Results of simulation indicate that this system can ensure circular grinding force steady and enhance the machining quality of cams when the grinding allowance is of variety.

Abstract: The accurate calculation and the approximate calculations of the cylinder cam’s curve enveloping surface in single-tool-position-compensation are compared. It is proved that the approximate formula is enough precision for engineering purpose. Based on the analyses for the approximate formula, the calculating method of the least feeding times of the multi-tool-position-compensation is proposed. This method provides theoretical foundation for complex surface’s high efficiency and great precision grinding as well as optimal machining control.