Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture
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Life cycle analysis of grinding: a case study of non-cylindrical computer numerical control grinding via a unit-process life cycle inventory approach It is estimated that the industrial sector is responsible for 29% of the United States’ greenhouse gas emissions. Recent efforts have sought to reduce the carbon footprint of manufacturing activities. Research suggests that a key to further reducing industrial-based greenhouse gas emissions is to more accurately characterize the carbon footprint of manufacturing processes. Life cycle assessment is a powerful tool that can be utilized to characterize the life cycle environmental impacts of a process. Current life cycle inventory databases that are used in life cycle assessments only have limited coverage on manufacturing operations. This article develops a parameterized process model for computer numerical control grinding, which enables the calculation of life cycle inventory data in a relatively rapid fashion and has some substantial characteristics, such as transparency, engineering quality, and the ability to reflect changes when new information is secured. Surface grinding of cobalt–chromium alloy knee implants is used as a case study to demonstrate the approach.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 226 Số 10 - Trang 1604-1611 - 2012
Hole quality and tool wear when dry drilling of a new developed metal/composite co-cured material The new developed metal/composite co-cured material composed of carbon fiber–reinforced plastic and Al phases has been increasingly applied for manufacturing of attitude control flywheel in aerospace industry. However, drilling of co-cured material is still a challenging task to produce holes with high quality and low cost in the assembly chain and dynamic balance debugging of attitude control flywheel. In other words, the relevant mechanisms and experimental findings involved in the drilling process of carbon fiber–reinforced plastic/Al co-cured material is not clearly defined, which impedes the progress of attitude control flywheel production. To this end, this article specially addresses the experimental studies on the drilling process of carbon fiber–reinforced plastic/Al co-cured material with standard TiAlN-coated cemented carbide twist drill. The significance of this work aims to reveal the regardful cutting responses of the hole characteristics and tool wear modes during the practical drilling process of co-cured material. A full factorial experiment including three levels of feed rate and four levels of cutting speed was performed. The hole diameter shows different values in different positions while it indicates consistent pattern regardless of the cutting variables: the largest in the Al phase, followed by the upper and lower carbon fiber–reinforced plastic phases, respectively. Grooves and matrix degradation are the major machining defects for carbon fiber–reinforced plastic layers, while a great chip debris adhered to the machined surface is the case for Al layer. Subsequent wear analysis showed that abrasion was mainly maintained at the vicinity of major/minor cutting edges and drill edge corner, followed by chip adhesion on the chisel edge region. Carbide substrate of drill flank face is exposed, and thereafter cavities are formed under the strong mechanical abrasion. These results could provide several implications for industrial manufacturers during the attitude control flywheel production.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 234 Số 6-7 - Trang 980-992 - 2020
Ultra-high-speed combined machining of electrical discharge machining and arc machining In this study, a new kind of ultra-high-speed combined machining of electrical discharge machining and arc machining was developed. A rotating graphite electrode and a workpiece were connected to the negative and positive poles of the power supply, which consisted of a pulse generator and direct current power. Efficient electrode injection flushing and side flushing yielded a noncontinuous arc and achieved a maximum material removal rate of 12,688 mm3 /min at a relative electrode wear ratio of 2.3% during quenched mold steel machining. The characteristics of the combined machining process were determined by studying the effects of flushing, rotation, peak current, and peak voltage on process performance, such as on the material removal rate and relative electrode wear ratio. The recast layer and surface defects were also investigated. The result shows that the novel combined machining process has great potential to reduce machining time.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 228 Số 5 - Trang 663-672 - 2014
Application of radial basis function neural networks in optimization of hard turning of AISI D2 cold-worked tool steel with a ceramic tool In this work, the optimization of a finish hard turning process for the machining of D2 steel with ceramic tools is carried out. With the help of replicate experimental data at 27 different cutting conditions, radial basis function neural network models are fitted for predicting the surface roughness and tool wear as functions of cutting speed, feed, and machining time. A novel method for neural network training is proposed. The trained neural network models are used as a black box in the optimization routine. Two types of optimization goal are considered in this work: minimization of production time and minimization of the cost of machining. One novel feature of this work is that the surface roughness is considered in the tool life instead of as a constraint. This is possible owing to the availability of the relationship of surface roughness with time in the neural network model. The results of optimization will be dependent on the tool change time and the ratio of operating cost to tool change cost. The results have been presented for the possible ranges of these parameters. This will help to choose the appropriate process parameters for different situations, and a sensitivity analysis can be easily carried out.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 221 Số 6 - Trang 987-998 - 2007
Fabrication of high melting-point porous metals by lost carbonate sintering process via decomposition route Porous metals with high melting points can be manufactured by the lost carbonate sintering (LCS) process either via the dissolution route or via the decomposition route. In the current paper, porous copper and steel samples with porosity in the range of 50 to 85 per cent and cell size in the range of 50 to 1000 μm have been produced via the decomposition route. The effectiveness of carbonate loss and the characteristics of the decomposition route have been studied. In comparison with the dissolution route, the decomposition route can be applied to a wider range of conditions and often requires shorter times to achieve a complete carbonate removal. The porous metal samples produced by the decomposition route generally have higher tensile strength and higher flexural strength than those produced by the dissolution route.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 222 Số 2 - Trang 267-271 - 2008
Prediction of Chip Flow Direction and Cutting Forces in Oblique Machining with Nose Radius Tools A method is described for calculating the chip flow direction in terms of the tool cutting edge geometry and the cutting conditions, namely feed and depth of cut. By defining an equivalent cutting edge based on the chip flow direction it is then shown how cutting forces can be predicted given the work material's flow stress and thermal properties. A comparison between experimental results obtained from bar turning tests and predicted values for a wide range of tool geometries and cutting conditions shows good agreement.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 209 Số 4 - Trang 305-315 - 1995
Optimum Cutting Conditions for Turned Components This paper describes the procedures used in a technologically orientated numerically controlled (NC-) system to determine the optimum culling conditions automatically for turning, drilling, grooving, threading and parting-off operations. In rough turning, the optimum depth and feed combination is determined using a direct search procedure on the allowable depth/feed region for chip control. The system determines the optimum depth of cut, feed and velocity for each pass in multi-pass turning on the basis of a user-selected objective criterion and a number of technological limitations that may apply to the process, such as machine power, dynamic instability, allowable range of depths and feeds for the tool and workholding limitations which include axial slip, circumferential slip and component throw-out. A user-friendly manual option is also provided which allows the user to specify the cutting parameters. Examples are given to illustrate how these procedures determine the optimum cutting conditions. A comparison between the machining costs and times using cutting conditions obtained from handbooks and the aforementioned procedures shows that for all the operations considered, there are cost and time savings when the cutting conditions obtained by the latter are used.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 206 Số 1 - Trang 15-31 - 1992
Prediction of Cutting Forces and Built-Up Edge Formation Conditions in Machining With Oblique Nose Radius Tools A semi-empirical machining theory is described for predicting cutting forces and temperatures for oblique nose radius tools from cutting conditions and a knowledge of work material flow stress and thermal properties. Predictions are made for a range of cutting speeds and tool geometries. It is shown how the cutting conditions giving a built-up edge can be determined from the predicted cutting temperatures. A comparison between predicted and experimental results shows good agreement.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 210 Số 5 - Trang 457-469 - 1996
Evaluating errors in screw rotor machining by tool to rotor transformation Screw compressor rotors are machined mainly by form grinding or milling tools. The precision requirements imposed upon them are today so demanding that the tool is allowed only limited wear and must be well set in the machine. It is therefore important to be able to quantify the tool set errors as well as to compensate for tool deformation and wear. Tool to rotor transformation is applied here to quantify these properties. Three possible errors are analysed, namely mismatch of the angle between the tool and rotor shafts, mismatch of the centre distance between the tool and the rotor, and mismatch in the axial tool position. The effect of tool deformation on the accuracy of the rotor is also considered. The effect of all three set errors is then used to compensate for the tool wear. A similar technique is valid for many machining processes in which form tools are used.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 220 Số 10 - Trang 1589-1596 - 2006
Effect of workpiece curvature on cutting forces and surface error in peripheral milling This paper investigates cutting forces and surface error due to cutting force-induced tool deflections in peripheral milling of curved geometries. In machining workpiece geometries, where curvature varies continuously along the tool path, both cutting force and surface error vary from point to point. This is different from the case of machining straight and circular geomtries where cutting forces and surface error are both invariant along the tool path. To study the effect of curvature, first force models for feed and normal cutting forces are derived from dynamometer measured forces. These force components are used to calculate tool deflection and resulting surface error. The results of this study show that both cutting forces and surface error are influenced strongly by workpiece curvature.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture - Tập 220 Số 9 - Trang 1399-1407 - 2006
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