Papers by Author: Cheng Zu Ren

Abstract: The characteristics, structural characteristics and composition of the grinding wheel oxide film is revealed by the theoretical analysis and simulating test in pre-dressing process of the ELID ultra precision mirror grinding, and the validity of oxide film formation mechanism analysis is verified by ELID experiments. Mirror grinding of hard brittle materials can be realized by on-line real-time control of the thickness of the oxide film.

Abstract: In this paper, an advanced 3D FE model was established using ABAQUS Explicit to simulate the process of milling aluminum-alloy 7075-T7451. Taking the end edge and the side edge of single flute into consideration, the model simulated the interaction between the spiral flute and wokpiece at full depth of cut. In addition, by defining automatic element deletion criterion and locally refining mesh, this model realized chip separating from workpiece without defining of cutting layer. The simulation results were compared with experimental data to verify the correctness of the simulation model.

Abstract: According to the feature of five-axis CNC machine tools’structure, do researches on post-process technique. By means of analysis of the kinetic model of five-axis CNC machine tools, Position and orientation of the tool in the workpiece coordinate system transforms to that of the machine coordinate system. Besides, Because of the rotation，Five-axises maching will produce the non-linear error．This article provides an easy algorithm to find the maximum non-linear error. Finally, an impeller, for example, simulates in the computer and machine by a 5-axis machine tool.

Abstract: This study focused on the side milling surface roughness of titanium alloy under various cooling strategies and cutting parameters. The experimental results show that the cooling strategies significantly affect the surface roughness in milling Ti-6Al-4V. Surface roughness (Ra) alterations are investigated. Cutting fluid strategy made nearly all the smallest and most stable roughness values. The surface roughness values produced by all cooling strategies are obviously affected by feed, radial depth-of-cut and cutting speed. However, axial depth-of-cut has little influence.

Abstract: Honing is an abrasive machining process that produces a precision surface on a workpiece and widely used in manufacturing engine cylinder walls, compressor bodies, valve bodies, bearings, hydraulic cylinders and so on. Investigation and acquisition of the honing force could be used to investigate the honing mechanism and optimize the processing parameter. But it is difficult to measure the force during the honing process because of the limited honing structure. This paper presents a measuring system for honing force. It introduces the measure theory and the measure system. The whole measuring system is validated by experiment.

Abstract: Honing is a finishing method by means of rotary motion and alternate motion between the honing stones assembled on the honing head and the workpiece. In honing process, the honing stone status is varying all the time and plays important role in cutting property. This paper analyzes the wear mechanism and the cutting property by cylindrical honing experiments. The wear mechanism is analyzed by the topography obtained by a microscope and the cutting property was investigated by two factors: material removal rate and honing force.

Abstract: Simulation of wheel surface topography is one key aspect of modeling the grinding process. A three-dimensional wheel topography model not only makes the simulated wheel topography more close to the real situation, but also benefits evaluation of wheel machinability and wears condition. This paper presents a physical model for simulation of three-dimensional wheel surface topography. Wheel structural components, grain shape, angle distribution of cutting edges, and the binding materials are considered in the model. Feasibility of the model is indicated by the simulation examples.

Abstract: Heat generation during cutting process affects the machined workpiece material and influences the cutting forces and tool wear. In this paper, a static thermal analysis model is developed to determine temperature rise in aluminum alloy (2A12) micro-cutting. The modified model is established based on two-dimensional steady state heat diffusion equation along with heat losses by convection film coefficients at the surfaces. A negative heat source is applied to simulate the heat loss during chip formation process. Effects of chip length and negative heat source on temperature distribution are discussed. The simulation results are compared with experiment data. The final results indicated that the model with negative heat source is more accurate than that without negative heat source and 20mm chip length give best temperature field fitting to the experiment.

Abstract: In order to predict fatigue life of hybrid ceramic ball bearing (HCBB) by Ioannides and Harris (IH) theory, the contact subsurface stress field is needed. The contact surfaces of ball and race groove are compatible. The closed-form analytical solution of compatible contact problem is hard to be obtained. The Finite Element Method (FEM) together with submodel technology is adopted to accurately and efficiently calculate the contact deformation and subsurface stress of ball–race groove contact. The result indicated that, the FEM with submodel technology considers the real contact deformation of ball-race groove, and can accurately and efficiently calculate the subsurface stress field. It is believed that the calculated subsurface stress field can be used in IH theory to predict fatigue life of HCBB.

Abstract: Abrasive machining is widely used as final machining process. It is still challenged to investigate the fundamental knowledge on the formation mechanism of groove and pile-up in single abrasive particle cutting. A 3D finite element analysis model to simulate single abrasive particle scratching on bearing steel (52100) workpiece with low cutting speed is proposed. An adaptive meshing technique is applied to handle large mesh deformation problem of the scratching process. The formation process of groove and pile-up for workpiece material is indentified qualitatively. The simulated results show that cutting speed has little effect on lateral profile. The height and area of pile-up increase with increase of depth of cut.