Papers by Author: Yi Ming Rong

Abstract: The time dependent behavior of grinding is expressed as the change of process output measures as a function of time during grinding. Although the wheel capability will be restored by dressing, the time dependent behavior of grinding during one dressing skip is determinant on the grinding quality variation in terms of surface integrity and workpiece geometric accuracy. Therefore, understanding of grinding time dependent behavior in relation with the wheel-workpiece microscopic interaction is critical for wheel and process development to achieve stable grinding processes. In this paper, the high speed grinding of inconel 718 with cBN grinding wheels is carried out. The time dependent behavior is recorded to represent the characteristic features. And the microscopic wheel topography is measured under SEM throughout the whole grinding process so as to reveal the root cause for the time dependent behavior and its impact on the workpiece quality variation.

Abstract: White light interferometer was employed to measure the surface topography of 60# and 120# alumina grinding wheel. The correlation of wheel topography and its performance was characterized through the three-dimensional (3D) surface characterization parameters of “Birmingham set”. Birmingham parameters were used to characterize the performances of grinding wheel, in items of grain density, grain shape and grain sharpness. The effects of sampling interval on the 3D surface parameters were analyzed and the optimal sampling interval was selected to calculate the 3D surface parameters.

Abstract: In the field of aeronautical and astronautical manufacturing, milling is a basic machining process by which a surface is generated by progressive chip removal. Therefore, this paper reports a complete procedure of the finite element model for the 3D oblique milling process using the commercial software package ABAQUS. Effect of various parameters on cutting forces is mainly discussed. The model correctly exhibits the observed transition from small to large force with increasing cutting speed and cutting depth.

Abstract: A finite element method (FEM) for predicting the temperature and stress distribution is presented. Two workpiece materials were carried out, one is Al7050-T6 the other is Ti-6Al-4V. The flow stress of workpiece material is taken as a function of strain, strain rate and temperature in order to reflect realistic behavior in machining process. Diamond cutting tool with rake angle 50, clearance angle 100, and cutting edge radius 1 is used. From simulation, cutting force, thrust force, and distribution of cutting temperature and stress are obtained.

Abstract: Grinding process can be considered as micro-cutting processes with the irregular abrasive grains on the surface of grinding wheel. The grain-workpiece interface directly forms the workpiece surface. Therefore, the study of the grain-workpiece interaction through micro-cutting analysis becomes necessary. But the experiments for single grain cutting are difficult to perform. Aimed at this problem, single grain cutting simulations of AISI D2 steel with a wide range of cutting parameters have been carried out with AdvantEdgeTM in this study. The effect of cutting parameters on cutting force, specific cutting force, material removal rate and critical depth of cut has been analyzed.

Abstract: This work employs Visual Basic and Access to develop a case database management system for flexible fixtures using coding technology and parameter driving technology. The database management system of fixtures’ cases is built. The secondary development of SolidWorks is performed by VB 6.0, and the system is transplanted to SolidWorks. The system can realize the fixtures’ auto coding, storage, search, display and system management with simple operation and convenient maintenance. The system has a large flexibility as the case database can be expanded and the fixtures’ parameters can be modified according to actual situation of enterprise without limitations of the software.

Abstract: This document Cutting stress coupled with clamping stress and initial stress affects the workpiece deformation. To analyze the workpiece deformation the initial stress model is developed. The finite element model of milling process is established and the milling force and milling heat is predicted. The multi-stress coupled model is developed and the workpiece deformation during machining process and deformation after fixtures released are predicted. This study is helpful to predict and control the deformation for thin-walled workpiece.

Abstract: In machining process, the workpiece is subject to cutting forces and torques. To resist these external loads, a fixture can supply clamping forces to completely restrain the workpiece. However, insufficient clamping forces cannot prevent the workpiece from translation and rotations, whereas excessive clamping forces may cause strongly the improper workpiece-fixture system deformations. Therefore, how to effectively determine the optimum clamping forces is the main objective of this paper. Firstly, a mechanistic model is proposed to measure the stability of clamping forces against these external loads. Secondly, a relaxation method is further established to true obtain the optimum clamping forces by solving the proposed model. The presented approach is conceptually simple and computationally efficient. It is particularly useful in the early stages of fixture design and process planning.

Abstract: The grinding process can be considered as micro-cutting processes with irregular abrasive grains on the surface of grinding wheel. Single grain cutting simulation of AISI D2 steel with a wide range of cutting parameters is carried out with AdvantEdgeTM. The effect of cutting parameters on cutting force, chip formation, material removal rate, and derived parameters such as the specific cutting force, critical depth of cut and shear angle is analyzed. The formation of chip, side burr and side flow is observed in the cutting zone. Material removal rate increases with the increase of depth of cut and cutting speed. Specific cutting force decreases with the increase of depth of cut resulting in size effect. The shear angle increases as the depth of cut and cutting speed increase. This factorial analysis of single grain cutting is adopted to facilitate the calculation of force consumption for each single abrasive grain in the grinding zone.

Abstract: Grinding is regarded as a special multiple edge cutting process, which can be decomposed into grain-workpiece interface, chip-workpiece/bond interface, and bond-workpiece interface at microscopic level. The grain-workpiece interface, which resembles a micro-cutting process, directly modifies the workpiece surface and dominates all the output measures of a grinding process. Therefore, the study of the grain-workpiece interaction through micro-cutting analysis becomes necessary. As the emergence of the packaged FEM software for micro-cutting simulation, apart from single grit cutting test, it enables another qualitative and quantitative investigation method on grain-workpiece interface mechanism in an efficiency and effective manner. In this paper, the efficacy of the commercialized cutting simulation software Third Wave AdvantEdgeTM is evaluated, and the possibility of using AdvantEdgeTM for in-depth understanding of grain-workpiece interface as well as grinding process modeling is studied, too.