Papers by Keyword: Cutting

Abstract: An aluminum/chromium based coating film, called (Al,Cr)N coating film, has been developed. This coating film has a slightly more inferior critical scratch load and micro-hardness. Therefore, to improve both the scratch strength and micro-hardness of the (Al,Cr)N coating film, the cathode material of an alumi-num/chromium/tungsten target was used in adding the tungsten (W) to the cathode material of the alumi-num/chromium target. To clarify the effectiveness of the aluminum/chromium/tungsten-based coating film, we measured the thickness, micro-hardness and critical scratch strength of aluminum/chromium/tungsten-based coating film formed on the surface of a substrate of cemented carbide ISO K10 formed by the arc ion plating process. The hardened steel ASTM D2 was turned with the (Al,Cr,W)N, (Al,Cr,W)(C,N), (Al,Cr)N and the (Ti,Al)N coated cemented carbide tools. The tool wear of the coated cemented carbide tools was ex-perimentally investigated. The following results were obtained: (1) The micro-hardness of the (Al,Cr,W)N or (Al,Cr,W)(C,N), (Al,Cr)N coating film was 3110 HV_0.25N or 3080 HV_0.25N, respectively. (2) The critical scratch load of the (Al,Cr,W)(C,N) coating film was 123 N, which was much higher than that of the (Al,Cr)N or (Ti,Al)N coating film. (3) In cutting the hardened steel using (Al,Cr,W)(C,N) and (Ti,Al)N coated carbide tools, the wear progress of the (Al,Cr,W)(C,N) coated carbide tool was almost equivalent to that of the (Ti,Al)N coated carbide tool. The above results clarify that the aluminum/chromium/tungsten-based coating film, which is a new type of coating film, has both high hardness and good adhesive strength, and can be used as a coating film of WC-Co cemented carbide cutting tools.

Abstract: As high silicon aluminum alloys have both a high strength-to-weight ratio and good wear-resistance, they are used for many automobile and motorbike parts. High silicon aluminum alloys are generally machined to improve dimensional accuracy. In cutting high silicon aluminum alloys such as Al-17mass%Si alloy, the primary Si particles have a negative influence on tool wear. Therefore, polycrystalline diamond compact cutting tools are widely used. In this study, in order to improve the tool wear resistance of polycrystalline diamond compact cutting tools, the Si particle size of Al-17 mass% Si alloy was changed by adjusting the water-cooling speed. Two different kinds of Si particle size, which were changed by adjusting the water-cooling speed, were used. The Al-17mass%Si alloy was turned with the polycrystalline diamond compact cutting tool and the tool wear was experimentally investigated. The main results were as follows: (1) The formed Si particle size was from 30 to 70 μm or from 40 to 170 μm. (2) The mechanical properties of the Al-17 mass% Si alloy did not depend on the Si particle size. (3) The Si particle size included in the Al-17 mass% Si alloy had a major influence of the tool wear, and it was possible to reduce the tool wear by increasing the Si particle size including that in the Al-17 mass% Si alloy.

Abstract: In this paper, construction of finite element analysis based on DEFORM^TM 3D four-blade face milling cutter aluminum 6061 cutting, explore the finite element analysis of face milling cutter rotating in a circle cutting of aluminum alloy 6061.Tool types used WC milling cutters, cutting speed, feed rate as fixed process parameters. The study analyzed four rotations of the blade face milling chip formation, effective stress, effective strain and material changes in temperature and tool wear.

Abstract: Precision grinding is one of the important processes for finishing of hardened steel parts. However, the grinding process might be quite costly providing the parts with shape complexity should be finished because a number of production steps are needed. Also, this process has some environmental issues, such as disposal of a large amount of grinding sludge and grinding fluid. Precision cutting would become a better alternative process to reduce cost and environmental burden because process steps can be simplified by use of CNC machine tools with PcBN cutting insert if deterioration of cutting tool edge by wear and chipping can be suppressed for long duration. In this study, to improve performance of a PcBN cutting insert, such as wear resistance and defect resistance by the applying of pulse laser processing to sharpen cutting edge in order to realize substitution of cutting for grinding. Precision cutting experiments for hardened steel are conducted by use of the PcBN insert with sharp and tough edges processed by pulsed laser and, for comparison, by use of the PcBN insert ground with diamond wheel. From the results of cutting experiments, it was found that precision cutting with PcBN insert processed by pulsed laser can provide a steady cutting state for a long cutting duration, and a smooth finished surface comparable to precision grindings.

Abstract: It is well known that a series of cracks running perpendicular to the cutting edge are sometimes formed on the rake face of brittle cutting tools during intermittent cutting. The cutting tool is exposed to elevated temperatures during the periods of cutting and is cooled quickly during noncutting times. It has been suggested that repeated thermal shocks to the tool during intermittent cutting generate thermal fatigue and result in the observed thermal cracks. Recently, a high speed machining technique has attracted attention. The tool temperature during the period of cutting corresponds to the cutting speed. In addition, the cooling and lubricating conditions affect the tool temperature during noncutting times. The thermal shock applied to the tool increases with increasing cutting speed and cooling conditions. Therefore, to achieve high-speed cutting, the evaluation of the thermal shock and thermal crack resistance of the cutting tool is important. In this study, as a basis for improving the thermal shock resistance of brittle cutting tools during high-speed intermittent cutting from the viewpoint of cutting conditions, we focused on the cooling conditions of the cutting operation. An experimental study was conducted to examine the effects of noncutting time on thermal crack initiation. Thermal crack initiation was found to be restrained by reducing the noncutting time. In the turning experiments, when the noncutting time was less than 10 ms, thermal crack initiation was remarkably decreased even for a cutting speed of 500 m/min. In the milling operation, the number of cutting cycles before thermal crack initiation decreased with increasing cutting speed under conditions where the cutting speed was less than 500 m/min. However, when the cutting speed was greater than 600 m/min, thermal crack initiation was restrained. We applied the minimal quantity lubrication (MQL) coolant supply to the intermittent cutting operation. The experimental results showed that the MQL diminished tool wear compared with that under the dry cutting condition and inhibited thermal crack initiation compared with that under the wet cutting condition.

Abstract: A fret-saw blade is commonly used in micromachining or curve machining of various woods. However, there is a curvature limit for machining of free-form surfaces because a fret-saw blade has a thickness of several hundred microns and a width of several millimeters. Additionally, cutting with a fret-saw blade produces much wood meal as chips. If a fine wire cutting tool is used, more flexible machining, such as machining of high curvature free-form surfaces, is possible and the quantity of chip production drastically decreases. The main purpose of this study is to clarify the fundamental machinability of anisotropic materials cut with a fine wire tool. In this report, we describe the machinability of various woods that are naturally anisotropic materials using a fine wire cutting tool that has electrodeposited diamond grains on its surface. In addition, this report discusses the performance of a trial manufactured hand tool employing the same wire cutting tool. The main conclusions obtained in this study are as follows. Acceptable machining of anisotropic woods is possible using a fine wire cutting tool, and the kerf width produced with this wire tool is narrower than that produced with a fret-saw blade. Additionally, the wood species and the cutting direction with respect to the wood grain have a significant influence on the machinability of various woods. Moreover, a relatively smooth cross section is provided when wood is cut by the hand tool using the fine wire tool.

Abstract: The microstructure of materials has a significant influence on tool life, however most of the research in modelling to date considers the material as homogeneous. This research aims to develop a microstructure-based Finite Element Model in order to qualitatively analyze the influence of the scale of the microstructure on the generated tool wear. In particular, this paper is focused on the orthogonal cutting process of a ferrite-pearlite dual-phase steel using uncoated carbide tools. Based on individual mechanical properties of these phases, a 3D coupled Eulerian Lagrangian heterogeneous model was developed. An empirical tool wear rate prediction model was implemented by a user subroutine in both models (heterogeneous and homogeneous) to predict wear and wear rate values. A comparison between the microstructure-base model (heterogeneous) and the homogeneous model considering wear and wear rate values was made. The results demonstrate the validity of microstructure-based Finite Element Model for an improved prediction of the wear phenomena.

Abstract: In order to improve both the scratch strength and the micro-hardness of (Al,Cr)N coating film, the cathode material of an aluminum/chromium/tungsten target was used in adding the tungsten (W) to the cathode material of the aluminum/chromium target. In this study, hardened sintered steel was turned with (Al60,Cr25,W15)N, (Al60,Cr25,W15)(C,N), (Al64,Cr28,W8)(C,N), (Al,Cr)N and (Ti,Al)N coated cemented carbide tools. The tool wear of the coated cemented carbide tool was experimentally investigated. The following results were obtained: (1) In cutting hardened sintered steel at the cutting speed of 0.42 m/s using the (Al60,Cr25,W15)N, the (Al60,Cr25,W15)(C,N), the (Al64,Cr28,W8)(C,N), the (Ti,Al)N and (Al,Cr)N coated tools, the wear progress of the (Al64,Cr28,W8)(C,N) coated tool became slowest among that of the five coated tools. (2) The wear progress of the (Al60,Cr25,W15)(C,N) coated tool was almost equivalent to that of the (Al64,Cr28,W8)(C,N) coated tool. However, at a high cutting speed of 1.67 m/s, the wear progress of the (Al60,Cr25,W16)(C,N) coated tool was faster than that of the (Al64,Cr28,W8)(C,N) coated tool.

Abstract: Austenitic materials have high demand in modern manufacturing industries due to their improved technological characteristics such as high mechanical strength and hardness, corrosion resistance, heat resistance and wear resistance. Some applications of austenitic materials include elevated pressure and temperature, and require stringent design requirements and close tolerances in manufactured products. Laser cutting is one of the non-conventional cutting processes, used to obtain complex shapes and geometries. In this paper, laser cutting was performed on austenitic material. The laser cutting process parameters are varied with the aim to obtain the optimal process parameters. The geometric and metallurgical characteristics of the cut parts are investigated and compared to the conventional cutting methods of austenitic materials.

Abstract: The paper presents results of simulation of stress-strain state of disk tools attachment points on tetrahedral prisms of working bodies of multipurpose roadheaders while cutting of coal and rock faces.