Papers by Keyword: Built-Up Edge

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Authors: Hiroki Kiyota, Fumihiro Itoigawa, Takashi Nakamura
Abstract: A chamfered cutting edge, which is commonly shaped in order to strengthen an edge of a cutting tool consisting of brittle material, easily causes an enhanced adhesion and a burr formation due to high compressive stress anterior to the edge. These problems lead to a detachment of tool material and a notch wear at depth-of-cut line, which would result in unexpected tool fracture. On the other hand, the edge shape promotes formation of a built-up edge (BUE) as a dead metal and can maintain it stably. Actually, the formed BUE is plastically extruded along to the chamfered edge and can prevent formation of the notch wear. In this study, basic experiments to reveal effects of chamfered tool edge preparation, such as chamfer angle, chamfer width and rake angle, on the BUE behavior were conducted. Additionally, the results suggested that the plastic flow in the BUE extrusion can suppress the adhesion if the extrusion is arisen uniformly. Therefore, attempts to control the BUE flow by chamfer surface modification were carried out.
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Authors: Johannes Kümmel, Jens Gibmeier, Volker Schulze, Alexander Wanner
Abstract: The tool and workpiece surface layer states of the tribosystem uncoated WC-Co cutting tools vs. normalised SAE 1045 workpiece material are studied in detail for a dry metal cutting process. Within the system the cutting parameters (cutting speed, feed rate, cutting depth) determine the wear state of the cutting tool and the resulting surface layer state (residual stress) in the workpiece. As the built-up edge can be used as a possible wear protecting layer [1] the influence of built-up edge and wear behaviour of the cutting tool was examined with respect to the workpiece surface layer state for knowledge based metal cutting processing. Small compressive stresses (-60-80 MPa) are induced in the surface layer, that are nearly homogeneous for the highest built-up edge, which lead to the lowest tool wear in combination with lowest cutting temperature.
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Authors: Daniel García-Jurado, José Manuel Mainé, Moisés Batista, Juan Manuel Vázquez-Martínez, Francisco Javier Puerta, Marinao Marcos
Abstract: The combination of specific properties, cost, reliability and predictable behavior, guarantee that the aluminium alloys will be kept as one of the materials used in aerospace industry. When aluminium alloys are machined, transfer of cutting material to cutting tool is related with the secondary or indirect adhesion wear mechanism, which can be presented in form of Built-Up Layer (BUL) and Built-Up Edge (BUE), located in two defined zones of the tool, cutting edge and rake face respectively. The material adhered involve tool properties, geometrical and physicochemical alterations which modify the initial cutting conditions, in accordance with currently concept of tool wear. Until now, a generalized lack is observed in methodologies to assessment the secondary adhesion wear in machining of aluminium alloys, mainly due to the difficulty found in characterizing and quantify thereof. In this paper, based in Focus-Variation Microscopy (FVM) techniques, a methodology is proposed through high-resolution optical 3D topography measurements obtained from WC-Co worn tools tested in the dry turning of UNS A92024-T3 alloy, in order to obtained information about effects and intensity of secondary adhesion wear.
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Authors: Shuang Chen, Wu Jun Lai
Abstract: The W6Mo5Cr4V2 high-speed steel tool was magnetized by an AC magnetization device which made by ourselves, and the cutting experiments were carried out in a general purpose machine with the magnetized high-speed steel tool and non-magnetized high-speed steel tool. The experimental results indicated that the cutting surface roughness of the workpiece could be improved by the magnetized W6Mo5Cr4V2 high-speed steel tool. Meanwhile the magnetization time and magnetization frequency should be regarded as the key of magnetization adjusting parameters. The magnetized W6Mo5Cr4V2 high-speed steel tool presented the different cutting performance under the different magnetization time and frequency, in which there were the better effects in low frequency. In addition, the experimental results also showed that the cutting force could be reduced during the cutting process by using of the magnetized W6Mo5Cr4V2 high-speed steel tool and the formation of the built-up edge in the tool could be inhibited, thereby the tool life was prolonged and the processing quality was improved.
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Authors: Ali Davoudinejad, Sina Alizadeh Ashrafi, Raja Ishak Raja Hamzah, Abdolkarim Niazi
Abstract: Aluminum alloy is widely used in industry and various researches has been done on machiability of this material mainly due to its low weight and other superior properties. Dry machining is still interesting topic to reduce the cost of manufacturing and environmental contaminations. In present study dry machining of Al 2024 investigated on tool life, tool wear mechanisms, hole quality, thrust force and torque. Different types of high speed steel (HSS) tools utilized at constant feed rate of 0.04 mm/rev and cutting speeds within the range of 28 and 94 m/min. Experimental results revealed that HSCo drills, performed better than HSS drills in terms of tool life and hole quality. The main wear mechanisms which analyzed by scanning electron microscope found abrasive and adhesion wear on flank face, besides, BUE observed at chisel and cutting edges. However tool wear and BUE formation found more significant at high cutting speed. In terms of thrust force, two facet HSCo tools, recorded higher thrust force than four facet HSS drills.
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Authors: J.M. Sánchez, M.A. Sebastián, J.M. González, M.S. Carrilero, Mariano Marcos Bárcena
Abstract: Tool adhesion wear can be produced by two different ways. On the one hand, direct adhesion wear is caused by the incorporation of tool particles to the chips. On the other hand, indirect adhesion wear is caused by the incorporation of fragment of the workpiece material to the tool. When these fragments are removed, they can drag out tool particles causing tool wear. Indirect adhesion can be localised in the tool edge, giving rise to Built-Up Edge (BUE), or in the tool rake face, giving rise to Built-Up Layer (BUL). In this work microstructural differences between both effects in different machining processes of Al-Cu alloys have been analysed. From these microstructural differences, a model has been proposed for the mechanism of formation of both effects.
181
Authors: Junya Okida, Hideki Moriguchi, Takao Nishioka, Hiromi Yoshimura
Abstract: In this paper, orthogonal cutting tests of alloy steel, aluminum alloy and Ti6Al4V have been carried out to consider the cutting mechanism from the viewpoint of friction between the tool and workpiece. The cutting processes were observed in detail using a high-speed video camera. The cutting process of alloy steel was greatly affected by its tribological properties compared with those of the other two work materials. In the cutting process of alloy steel, there were three stages in relation to the state of the tool rake face and temperature. The difference between non coated and coated tools was marked in the later stages. From the discussion on the experimental results, it is considered that the thrust force is suitable for representing the tribological properties between the tool and workpiece. It is concluded that the orthogonal cutting test is a good method for evaluating tribological properties between the tool and workpiece.
169
Authors: Xiao Qi Song, Yukio Takahashi, Wei Ming He, Tohru Ihara
Abstract: Built-up Layer (BUL)/Built-up Edge (BUE) formed on the tool surface can be treated as a protective, thermal barrier or lubricant films especially in the extreme severe conditions when machining the metal materials, which can sustain the tool effective and wear resistance. In order to have a thorough understanding of the adhesion effect during machining, experiments have been carried out to investigate the performance and the formation mechanisms of adhering layer on the carbide tool in machining of aluminium alloys A6063, carbon steel S45C and difficult-to-cut hardened steel S45C (H-S45C). The morphology of tool adhered surface was examined by employing Scanning Electron Microscopy (SEM), the dimensions of adhering layer were measured by Laser Scanning Microscopy (LSM) and the elements on the tool were analyzed by Electron Probe Micro Analyser (EPMA), respectively. The atomic-scale cluster adhesive friction model is proposed to explain the tool-chip contact conditions, which considers the nature of the shear strain, shear strain rate and temperature distribution in the secondary deformation zone. The model is a dynamic model and the rate equation approach can be applied to estimate the formation process of adhering layer during machining. Results have shown that the adhering layer will give rise to BUL on the tool rake face and the BUE on the cutting edge and clearance face.
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