Advanced Materials Research Vols. 24-25

Abstract: The practice and evaluation of elementary management of technology (hereafter, MOT) education has previously been investigated. It is recognized that elementary MOT education using trading games (hereafter, TG) has great educational effects on the awareness of the importance of MOT skills. On the other hand, a large amount of preparation time and labor is required when elementary MOT education using TG is first introduced into elementary schools. Development of a practical guidebook for elementary engineering management (hereafter, EM) education would likely be a useful educational tool for elementary EM education, and may then be applied in many elementary schools. In this study, a guidebook for elementary EM education is proposed, and its educational effects are verified. The practical application of elementary EM education to the finishing technology will be completed in the future works.

Abstract: The formation and existence of burrs is one of the common phenomena in machining. It affects directly machining accuracy and parts quality. Network database system for metal cutting burr is developed using ASP.NET platform. The management of metal cutting burr data, inquiry and prediction of cutting burrs types and sizes, optimization of cutting conditions for controlling burr forming which based on the reasoning method of BP neural networks are realized. The development and realization of network database of metal cutting burr provide a convenient way for data transmission between multi-workshop and across regions, promote the development of burr controlling technology and modern manufacture technology.

Abstract: It is difficult to select the materials combining in modern industry, this paper analyzed the drawbacks of different materials (the stainless, the copper alloys, aluminum and its alloys) on selecting materials for tooling and selection of coatings that help to eliminate drawbacks, analyzed the micro-arc oxidation (MAO) and its application of different materials. It is ascertained that aluminum alloys may be practical to use for electrodes for electroerosive machining only in exceptional cases when the wear of the tool is not determinative. Selection of materials combining required physical and mechanical properties may be a difficult task in tooling designing and manufacturing in modern industry. This problem is especially evident when current-conducting elements of tooling used for electrophysical and electrochemical processing methods are manufactured. The main distinctive feature of these methods is maintenance of values under the influence of electrical current and corrosive medium and during electrochemical reactions. The article addresses comparative analysis of properties of different materials used for tooling manufacture, advantages and drawbacks of these materials and selection of coatings that help to eliminate drawbacks. When selecting materials for tooling, the alloy in use shall have the following properties [4]: high electrical conductivity, high corrosion resistance, high resistance to local fracture, high adhesion to dielectric coatings, sufficient mechanical strength, high machinability and low cost. The following materials are considered to meet operating requirements to the fullest extend [4.5]: stainless steels and copper alloys that have high machinability, electrical conductivity, weldability and mechanical strength; titanium- and chromium-base alloys that have high mechanical strength, corrosion resistance and resistance to local fracture and enables to make oxide insulating layer protecting surface from anodic dissolution. However, these materials have a number of drawbacks, the most important of which is high cost that impedes their usage especially in serial production. Furthermore, stainless steels and titaniumand chromium-base alloys have the following drawbacks that affect product cost: - complexity of machinability that results in high labor-intensiveness of manufacturing process of tooling; - heavy losses in electric voltage provided that these materials are used as current-carrying elements that makes current supply calculation difficult and requires application of more powerful sources; - cracking and fracture of oxide surface coating even when mechanical effect is insignificant that results in loss of isolating and protective properties [1,2]. Furthermore, oxide coating application process cannot be controlled completely and as a result, coating uniformity in thickness, composition and properties cannot be achieved. Application of coatings to the areas with varied sections and to the surfaces with projections and sharp edges is a difficult problem. Layers applied to these surfaces have little adhesion to parent material and their thickness is limited due to high stress concentration and etching. The revealed drawbacks require development and usage of surface layer improvement process to receive required physical and mechanical properties of composite material.

Abstract: Two-phase swirling flows finishing is put forward mainly for hole surface. By theoretic analysis and experimental research, the characteristics of flows field will directly affect finishing quality and efficiency. On the basic premise of defining Renault stress model on swirling flows field, numerical simulation of velocity vector graph, turbulent kinetic energy graph, turbulent dissipation ratio graph, pressure distribution graph, vorticity magnitude distribution graph etc. are made, and vorticity magnitude and tangential velocity in different mediums are contrasted, which provide theoretic basis for thorough research.

Abstract: The sharp burrs produced by plastic deformation during machining of the precision components deteriorates the precision and performance of a machine. Thus, effective removal of the burrs may improve productivity and performance of the machinery. This study was conducted based on the experiment to remove fine burrs produced during machining process using the magnetic abrasive finishing method. The magnetic abrasive finishing using the abrasive feature of an abrasive and the magnetic nature of iron is an abrasive method to brush the burrs with iron powder that has a cohesive power due to the line of induction. The purpose of this study is to remove the burrs at intersecting holes which are difficult to access with tools, using the magnetic abrasive finishing method. Special tool is designed for deburring micro burr at intersecting holes. To find the proper deburring condition, gap distance, rotational speed of inductor, components of powder and effect of coolant are analyzed.

Abstract: Based on the orthogonal cutting experiments, the two side direction burrs in metal cutting were studied. In this study, the cutting model of two side direction burr formation and translation is established with plane stress-strain theory. The main laws of formation and change of burr in size and type in orthogonal cutting are revealed, and it is confirmed by experiment results, which first realizes control of the forming and change of the two side direction burr in metal cutting operation.

Abstract: Using solid carbide straight end mills with TiAlN coating, A P20 steel at 41HRC is machined in the cutting speed range of 301 to 754m/min. The workpiece subsurface are examined using scanning electron microscope (SEM) and surface roughness tester. The results show that the white layer is produced in all of the cutting conditions tested, and the white layer thickness and surface roughness are dependent on the cutting conditions. The result obtained by analysis of variance analysis shows that feed rate and cutting speed are the most significant effects on the white layer thickness and surface roughness. Furthermore, the mathematical models for the white layer thickness and the surface roughness in high speed side milling of hardened P20 steel are proposed, respectively.