Investigation of secondary deformation zone and mean coefficient of friction during the machining of 5083-H34 aluminum alloy
TL;DR: In this paper, an experimental analysis was performed to evaluate the width of the secondary deformation zone and the mean coefficient of friction during the machining of 5083-H34 aluminum alloy.
Abstract: An experimental analysis was performed to evaluate the width of the secondary deformation zone and the mean coefficient of friction during the machining of 5083-H34 aluminum alloy. Dry orthogonal cutting tests using high speed steel and sintered carbide tools of different rake angles were carried out at a wide range of feed rates at constant cutting speed for tubular workpieces. The width of the secondary deformation zone and the mean coefficient of friction were found to be direct functions of the parameters involved in the cutting process. The results were analyzed in terms of the variation in the mean tool-chip contact temperature and its influence on the specific tangential load and specific normal pressure on the tool face.
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TL;DR: In this paper, the analytical and experimental study on the high-speed face milling of 7075-T6 aluminum alloys with a single insert fly-cutter was conducted.
Abstract: This research is concerned with the analytical and experimental study on the high-speed face milling of 7075-T6 aluminum alloys with a single insert fly-cutter. The results are analyzed in terms of cutting forces, chip morphology, and surface integrity of the workpiece machined with carbide and diamond inserts. It is shown that a high cutting speed leads to a high chip flow angle, very low thrust forces and a high shear angle, while producing a thinner chip. Chip morphology studies indicate that shear localization can occur at higher feeds even for 7075-T6, which is known to produce continuous chips. The resultant compressive residual stresses are shown for the variation of cutting parameters and cutting tool material. The analysis of the high-speed cutting process mechanics is presented, based on the calculation results using extended oblique machining theory and finite element simulation.
141 citations
Metz1
TL;DR: In this paper, the authors used a numerical high-speed camera to take photographs of chips during the cutting process for a large range of speeds, ranging from 17 to 60m/s.
Abstract: The originality of this work consists in taking photographs of chips during the cutting process for a large range of speeds. Contrary to methods usually used such as the quick stop in which root chips are analyzed after an abrupt interruption of the cutting, the proposed process photographs the chip geometry during its elaboration. An original device reproducing perfectly orthogonal cutting conditions is used because it allows a good accessibility to the zone of machining and reduces considerably the vibrations found in conventional machining tests. A large range of cutting velocities is investigated (from 17 to 60 m/s) for a middle hard steel (French Standards XC18). The experimental measures of the root chip geometry, more specifically the tool-chip contact length and the shear angle, are obtained from an analysis of the pictures obtained with a numerical high-speed camera. These geometrical characteristics of chips are studied for various cutting speeds, at the three rake angles −5, 0, +5° and for different depths of cut reaching 0.65 mm.
124 citations
Cites methods from "Investigation of secondary deformat..."
...Radwan [5] measured the chip-tool contact length for aluminum alloy, by measuring the scour trace on the tool face using toolmaker’s microscope....
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TL;DR: In this paper, the effects of tool edge radius on the frictional contact and flow stagnation phenomenon, the stick-slide behavior and contact stress distributions, the evolutions of contact length, and the relationship between material deformation and total contact length were investigated.
Abstract: The contact phenomenon during micromachining is complicated due to the tool edge radius. This paper presents investigation of the effects of tool edge radius on the frictional contact and flow stagnation phenomenon, the stick–slide behavior and contact stress distributions, the evolutions of contact length, and the relationship between material deformation and total contact length. Through the arbitrary Lagrangian–Eulerian FE modeling approach, our findings revealed that the flow stagnation during material separations could be attributed to the counterbalance of shear contact components and it appeared to be insensitive to machining magnitude where a constant stagnation point angle of 58.5±0.5° was determined for a wide range of undeformed chip thicknesses. Three distinctive sticking and sliding regions associated with the flow stagnation phenomenon on the cutting tool were discovered following the identification of two stress criteria for sticking, τf=0 and/or τf=kf. In addition, the influence of tool edge radius on contact length and material deformation was determined and a theoretical model for the contact length of tool-based micromachining was proposed. It was also observed that tool–chip contact evolved in two successive stages through a series of intermittent sticking and sliding interactions as governed by the undeformed chip thickness and the transition of effective rake angle. An ultraprecision machining setup coupled with a high-speed and small field-of-view photography technique was proposed for experimental substantiation of the numerical results.
97 citations
TL;DR: In this article, the machinability characteristics of Incoloy 825 using an uncoated tool, chemical vapor deposition of a bilayer of TiCN/Al2O3, and physical vapor deposition (PVD) of alternate layers of TiAlN/TiN-coated tools under varying machining conditions were investigated.
Abstract: With wide applications of nickel-based superalloys in strategic fields, it has become increasingly necessary to evaluate the performance of different advanced cutting tools for machining such alloys. With a view to recommend a suitable cutting tool, the present work investigated various machinability characteristics of Incoloy 825 using an uncoated tool, chemical vapor deposition (CVD) of a bilayer of TiCN/Al2O3, and physical vapor deposition (PVD) of alternate layers of TiAlN/TiN-coated tools under varying machining conditions. The influence of cutting speed (51, 84, and 124 m/min) as well as feed (0.08, 0.14, and 0.2 mm/rev) was comparatively evaluated on surface roughness, cutting temperature, cutting force, coefficient of friction, chip thickness, and tool wear using different cutting tools. Although the CVD-coated tool was not useful in decreasing surface roughness and temperature, a significant reduction in cutting force and tool wear could be achieved with the same coated tool under a high ...
31 citations
Dissertation•
15 Nov 2005
27 citations
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TL;DR: An analysis of the chip geometry and the force system found in the case of orthogonal cutting accompanied by a type 2 chip has yielded a collection of useful equations which make possible the study of actual machining operations in terms of basic mechanical quantities as mentioned in this paper.
Abstract: An analysis of the chip geometry and the force system found in the case of orthogonal cutting accompanied by a type 2 chip has yielded a collection of useful equations which make possible the study of actual machining operations in terms of basic mechanical quantities. The shearing strain undergone by the metal during chip formation, and the velocities of shear and of chip flow are among the geometrical quantities which can be quantitatively determined. The force relationships permit calculation of such quantities as the various significant force components, stresses, the coefficient of friction between chip and cutting tool, and the work done in shearing the metal and in overcoming friction on the tool face. The experimental methods by which such analyses can be readily made are described. Observed and calculated values from typical tests are presented.
1,152 citations
01 Jun 1963
TL;DR: In this paper, the authors used a photographic technique for the determination of the complete temperature distribution in the orthogonal metal cutting process; they are found to disagree with previous theoretical predictions.
Abstract: The results of a photographic technique for the determination of the complete temperature distribution in the orthogonal metal cutting process are presented; they are found to disagree with previous theoretical predictions. The temperatures along the tool rake face are of particular interest because they are thought to affect the wear of the cutting tool and friction between the chip and tool; it is found that these temperatures have been considerably over-estimated by previous work. By introducing the width of the secondary deformation zone, i.e. the extent of sub-surface deformation due to friction at the tool-chip interface, as a new variable, it is found that more consistent predictions of rake face temperatures can be made. From this work information has been obtained on the shape of the zones of plastic deformation in metal cutting and on the distribution of heat generation within these zones.
251 citations
TL;DR: In this paper, it was shown that the normal characteristics of sliding friction do not hold for the friction between chip and tool, and several explanations for the variance in sliding friction were proposed.
Abstract: An examination of previous work on metal cutting reveals that the normal characteristics of sliding friction do not hold for the friction between chip and tool. Several explanations for the variati...
85 citations
TL;DR: In this paper, the authors show that there is a good correlation between contact length and the thermal conductivity of the tool material and conclude that contact length is predominantly governed by the variation of the temperature field in the tool-chip contact zone.
Abstract: The natural tool-chip contact length is affected by a large number of parameters in the cutting system, one of which is the tool material. Wide variation of the contact length is observed in machining of steel with tools of different grades, distributed over the whole range of sintered carbides, all other variables being kept constant. Experiments show that there is good correlation between contact length and the thermal conductivity of the tool material. Based on the results of the experiments, the conclusion is drawn that contact length and chip curl are predominantly governed by the variation of the temperature field in the tool-chip contact zone.
59 citations