Materials Science Forum Vols. 471-472

Abstract: In this paper, a finite element model of a two-dimensional orthogonal metal cutting process is used to simulate the chip formation, cutting forces, stress, strain and temperature distributions. Two deformable parts are involved in this model: the workpiece and the cutting tool. To make the results of the simulation agree the orthogonal cutting test better, the separation surface between the chip and the machined surface is not predefined in this simulation. The chip-separation criterion is based on the Johnson and Cook law. This work will help as a reference to tackle more complex cutting processes such as oblique and discontinuous cutting.

Abstract: This paper presents the method and process of the real-time error compensation (RTEC) on NC machine tools, which includes: identification and measurement of error components, separating and modeling of geometric-thermal error components, geometric-thermal volumetric error synthesis model, compensation control system, performance evaluation of error compensation by the body diagonal displacement measurement, and the industry application of real-time error compensation. The technique has been successfully applied to many different NC machine tools in the plants for practical production, and the machining accuracy of the NC machine tools is improved by an order of magnitude with low cost.

Abstract: A new analytic model for the inverse kinematics of redundant robot is developed based on optimization measure that is defined as a criterion to determine the optimization adaptability. A smoothly continuous function of optimization measure is derived. The redundant seven-DOF robot is kinematically simulated using MATLAB software. Results show that self-motion of joints can vary continuously and the joint angular velocity can be controlled within the smaller range by using the new model for the inverse kinematics of redundant robot.

Abstract: The calescent superplastic bulge forming (CSPBF) of Ti-6Al-4V (TC4) alloy sheet was investigated using experimental method, and carried out the research that optimized its technological parameters using fuzzy neural network (FNN) . The experimental results show that the CSPBF may save processing time, can also improve materials’ formability as well as get ideal microstructure. The study indicated that the FNN adapt to solve complex nonlinear problem such as technological parameters of CSPBF of TC4 sheet. Utilizing optimized technological parameters successfully have formed the part of aerostat, the nonuniformity of wall thickness is less than 8% and part' forming time may be shorten 10minute.

Abstract: Based on the functional requirement analysis of the compute-aided reliability information system, some concepts are proposed, such as the distributed progressive reliability analysis and the functional decomposition and reconstitution for CNC machine tool. At the same time, the architecture of the CARNC-CE (Computer Aided Reliability Numerical Control for Current Engineering) including physical layer, foundational layer, executive layer, applied layer and illustration layer, is introduced, which provides the general guidance and the frame to realize CNC machine tool reliability analysis system in concurrent engineering.

Abstract: Nowadays, with the advances of Finite Element Analysis (FEA) packages, some of the engineering and design problems such as stress or thermal deformation can be successfully solved. These are convenient for better incorporating the design constraints of various tasks such as injection molded parts, or rapid prototyping and tooling. Mesh generation is the major step of finite element method for numerical computation. Common types of mesh include triangulation or tetrahedralization. During the mesh generation process, we always find difficulty in the formation of a uniform, non-conformal mesh. The undesirable mesh will adversely influence the accuracy and meshing time of the model. This paper will, thus, propose an effective approach to extend to threedimensional (3D) mesh generation by octree balancing method so as to adjust the mesh pattern. In this paper, the implementation of octree balancing will be explained and illustrated with real life example. The proposed method includes three main steps. Problematic unbalanced octants will be detected and Steiner points will be added as appropriate before the tetrahedral mesh generation. The balanced octree will form good tetrahedral meshes for further analysis. Then the balanced and unbalanced meshes will be compared for efficiency and accuracy for mesh generation.

Abstract: The TRIZ theory of technology evolution is introduced and its limitations in new product development is assessed in this paper, Based on the multiple approaches evolution patterns of TRIZ Theory, a decision-making procedure model for new product development is proposed and a sample product is used to demonstrate how to use new model to the real developing procedure of a new product.

Abstract: Rapid manufacturing moulds by plasma arc spraying is a new kind of plasma arc machining technology. This technology has many advantages. An experimental apparatus has been set up. The influence of some special factors on the surface quality of work moulds formed by plasma arc spraying have been analyzed and experimentally researched. The micro structure of the interface between master moulds and work moulds shows that work moulds copy geometrically master moulds very well after optimizing processing parameters. Some experimental samples by plasma arc spraying have been obtained. They show that the surface patterns of work moulds match with the ones of master molds very well.

Abstract: An investigation is reported of the characteristics of specific energy in grinding of granite using diamond abrasives. The effects of many parameters, such as the types of diamond tools, the types of abrasives, the properties of granite, the conditions of lubrication, and the working conditions of diamond tools, were studied. The power consumed in grinding was measured in order to obtain the specific energy, which is defined as the energy expended per unit volume of material removal. It is found that the specific energy for grinding of granite was closely related to the removal mechanisms of granite, the failure modes of diamonds and the interactions of the swarf with the applied fluid and bond matrix.

Abstract: Bond strength is a key property to evaluate quality of cladding layer. According to the thickness of the cladding, surface cladding layer can be classified into two categories: thick and thin layer. The later is usually called thin film. Bond strength includes static and dynamic bond strength. As to thick cladding layer, main measuring methods of static bond strength are sticking extension method, interfacial indentation method, shearing method, fracture mechanics method. Contact fatigue method is the main measuring method of dynamic bond strength. As to thin film, main measuring methods of static bond strength are extension method, scratching method, indentation method, scraping method, bulge blister method, laser spallation method and so on. The main measuring methods of dynamic bond strength are facing contact rolling method and ball contact rolling method. The paper made overview on all above methods.