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Showing papers on "Machining published in 1995"


Journal ArticleDOI
TL;DR: In this paper, a Lagrangian finite element model of orthogonal high-speed machining is developed, which accounts for dynamic effects, heat conduction, mesh-on-mesh contact with friction, and full thermo-mechanical coupling.
Abstract: A Lagrangian finite element model of orthogonal high-speed machining is developed. Continuous remeshing and adaptive meshing are the principal tools which we employ for sidestepping the difficulties associated with deformation-induced element distortion, and for resolving fine-scale features in the solution. The model accounts for dynamic effects, heat conduction, mesh-on-mesh contact with friction, and full thermo-mechanical coupling. In addition, a fracture model has been implemented which allows for arbitrary crack initiation and propagation in the regime of shear localized chips. The model correctly exhibits the observed transition from continuous to segmented chips with increasing tool speed.

529 citations


Journal ArticleDOI
P.P. Pronko1, Subrata Dutta1, Jeff Squier1, J. V. Rudd1, D. Du1, Gerard Mourou1 
TL;DR: In this article, a Ti:sapphire laser was used to ablate holes with a diameter of 300 nm and a depth of 52 nm to produce very small features in materials.

457 citations


Journal ArticleDOI
TL;DR: In this article, the Iosipescu shear test was used to evaluate the inplane shear strength of fiber angle test specimens and a model for predicting the cutting forces and the dependence of cutting direction on machinability requirements was presented.
Abstract: With the increasing use of fiber reinforced plastic (FRP) composites outside the defense, space and aerospace industries, namely, civilian industries, machining of these materials is assuming a significant role. Unit cost rather than solely performance at any cost will be the consideration for the implementation of FRP composites to consumer industries. The current knowledge of machining FRP composites, unfortunately, is inadequate for its optimum utilization in many applications. This paper presents some observations made on the orthogonal machining of unidirectional carbon fiber reinforced plastic (UD-CFRP) laminates with different fiber orientations. Iosipescu shear test was adopted to evaluate the inplane shear strength of varied fiber angle test specimens. A model for predicting the cutting forces and the dependence of cutting direction on machinability requirements is presented.

306 citations


Journal ArticleDOI
TL;DR: In this article, a feed-forward neural network is used to associate the cutting parameters with the cutting performance and a simulated annealing (SA) algorithm is applied to the neural network for solving the optimal cutting parameters based on a performance index within the allowable working conditions.
Abstract: Owing to the complexity of wire electrical discharge machining (wire-EDM), it is very difficult to determine optimal cutting parameters for improving cutting performance. The paper utilizes a feedforward neural network to associate the cutting parameters with the cutting performance. A simulated annealing (SA) algorithm is then applied to the neural network for solving the optimal cutting parameters based on a performance index within the allowable working conditions. Experimental results have shown that the cutting performance of wire-EDM can be greatly enhanced using this new approach.

280 citations


Journal ArticleDOI
TL;DR: In this article, a new cutting method named ultrasonic elliptical vibration cutting is proposed and applied to cutting of metals by utilizing a new vibrator to vibrate the cutting tool elliptically at ultrasonic frequency.

236 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a model of the environmental impact of machining processes, which integrates aspects of the process mechanics, wear characteristics and lubricant flows, including energy utilization, process rate, primary mass flow, and secondary flow of process catalysts.

227 citations


Journal ArticleDOI
01 Sep 1995-Wear
TL;DR: The role of friction in nano-scale machining has been investigated using a new molecular dynamics simulation model based on the Nose-Hoover method, in which the restricted analytical region moves together with the tool advancement.

212 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of additives in kerosene used as the dielectric fluid for EDM were studied and the results showed that the additives can increase the MRR and decrease the TWR and improve the surface quality of the work quite clearly, especially in mid-finish machining and finish machining.

172 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed models to predict the thrust and torque forces at the different regions of cutting on a drill, and validated these models independently for the cutting lips and the chisel edge for drilling both metals and fiber-reinforced composite materials for a wide range of machining conditions and drill geometry.
Abstract: In this paper models are developed to predict the thrust and torque forces at the different regions of cutting on a drill. The mechanistic approach adopted to develop these models exploits the geometry of the process, which is independent of the workpiece material. The models are calibrated to a particular material using the well-established relationships between chip load and cutting forces, modified to take advantage of the characteristics of the drill point geometry. The models are validated independently for the cutting lips and the chisel edge for drilling both metals and fiber-reinforced composite materials for a wide range of machining conditions and drill geometry. While the cutting-lips model predictions agree well with the experimental data for both materials, only the chisel-edge model proposed for metals agrees well with the experimental data.

149 citations


Journal ArticleDOI
TL;DR: In this article, a computer-aided design procedure for the horn profile and material, based on finite-element analysis, has been established and a new design profile is suggested, using parts with different geometries.

146 citations


Journal ArticleDOI
TL;DR: In this paper, a synthetic consideration of electrode wear phenomena in electrical discharge machining is presented, where the authors deal with a synthetic approach to evaluate the wear rate of an electrode in the stationary state of machining, taking account of turbostratic carbon on the electrode.

Journal ArticleDOI
TL;DR: In this paper, a plane-strain finite element method for the simulation of orthogonal metal cutting with continuous chip formation is presented, including the effects of elasticity, viscoplasticity, temperature, large strain, and high strain-rate.
Abstract: The development and implementation of a plane-strain finite element method for the simulation of orthogonal metal cutting with continuous chip formation are presented. Detailed work-material modeling, including the effects of elasticity, viscoplasticity, temperature, large strain, and high strain-rate, is used to simulate the material deformation during the cutting process. The unbalanced force reduction method and sticking-sliding friction behavior are implemented to analyze the cutting process. The deformation of the finite element mesh and comparisons of residual stress distributions with X-ray diffraction measurements are presented. Simulation results along the primary and secondary deformation zones and under the cut surface, e.g., the normal and shear stresses, temperature, strain-rate, etc., are presented revealing insight into the metal cutting process

Journal ArticleDOI
TL;DR: This paper describes research on algorithms for the toolpath generation of five-axis cylindrical milling of sculptured surfaces with cylINDrical cutter, which includes (a) single point offset (SPO) algorithm, and (b) double point offset ("DPO") algorithm for the cutter location data (CLDATA) calculation ofFive-axis cylinder milling.
Abstract: In theory, the five-axis numerical control (NC) machining of sculptured surfaces can be classified into facing milling and cylindrical milling (or side milling). In general, the first one, using flat-end cutter, is suitable for the machining of large sculptured surfaces, e.g. the blade of hydraulic turbine, whose binding relations with drive surface (DS) and check surface (CS) are simple, and the second one, using cylindrical cutter, has wide applications for the milling of small and middle dimensional surfaces whose binding relations with DS and CS are more complex, such as the milling of integral turbine wheels. In practice, the second one suffers more difficulties than the first one, which are mostly related to gouge avoidance, interference avoidance and tool strength. This paper, on the basis of the theories of differential geometry and analytical geometry, describes research on algorithms for the toolpath generation of five-axis cylindrical milling of sculptured surfaces with cylindrical cutter. The approach includes (a) single point offset (SPO) algorithm, and (b) double point offset (DPO) algorithm for the cutter location data (CLDATA) calculation of five-axis cylindrical milling.

Journal ArticleDOI
TL;DR: In this article, a generalized hypothesis for the brittle to ductile transition in micromachining and microindentation of brittle materials is proposed, which explains complicated transition phenomena observed in practical machining processes.

Journal ArticleDOI
TL;DR: In this paper, the results obtained are useful in describing the damage history and to help design drill geometries specifically conceived for composite machining, and qualitative agreement of the observed behaviour with the predictions of the model presented in the literature is assessed.
Abstract: In the drilling of reinforced plastics the quality of the cut surfaces is strongly dependent on the appropriate choice of drilling parameters. The aim of this work is to clarify the interaction mechanisms between the drilling tool and material. Drilling tests were carried out on glass-polyester composites using standard HSS tools; drilling was interrupted at preset depths to study damage development during drilling. The specimens, polished by a metallographic technique, were examined by optical microscopy to identify any damage. The results obtained are useful in describing the damage history and to help design drill geometries specifically conceived for composite machining. The qualitative agreement of the observed behaviour with the predictions of the model presented in the literature and some of their intrinsic limitations are assessed.

Journal ArticleDOI
TL;DR: In this article, a new approach to extend rotary ultrasonic machining to face milling of ceramics is proposed, which keeps all the material removal mechanisms of rotary UML machining.
Abstract: Among the various material removal processes applicable to ceramic materials, rotary ultrasonic machining has the potential for high material removal rate while maintaining low machining pressure and resulting in less surface damage. The limitation of rotary ultrasonic machining is that only circular holes or cavities can be machined due to the rotary motion of the tool. Attempts have been made by other researchers to extend rotary ultrasonic machining process to machining flat surfaces or milling slots. However, these extensions either changed the material removal mechanisms or had some severe drawbacks. One of the reasons for this might be an insufficient understanding of the material removal mechanisms involved. In this paper, a new approach to extend rotary ultrasonic machining to face milling of ceramics is proposed, which keeps all the material removal mechanisms of rotary ultrasonic machining. The development of the experimental apparatus and the design of the cutting tool are described. Preliminary experimental results are presented and discussed.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the behavior of the chip formation using various metallurgical analysis techniques and found that some non-diffusional phase transformation took place in the shear localized chips.
Abstract: Adiabatic shear banding is a phenomenon observed in machining titanium and some other metals and alloys as well. The shear localized chips are important in the chip disposal process, machined surface integrity and the automation of machining operations. It is therefore necessary to understand the mechanisms of metal cutting such as the formation of shear banding in the produced chips. In this paper, the behaviour of the chip formation is investigated using various metallurgical analysis techniques. It was found, in cutting Ti-6wt.%Al-4wt.%V titanium alloy, that some non-diffusional phase transformation took place in the shear localized chips. The process of chip formation with shear banding and the effects of cutting conditions on shear banding frequency were also studied. The results of these tests are presented in this paper.

Journal ArticleDOI
TL;DR: In this paper, a single-point continuous turning test was carried out on a G-17 cast iron and a nickel base, Inconel 718, alloy using round and rhomboid-shape pure oxide (Al 2 O 3 + ZrO 2 ) and mixed oxide (al. 3 + TiC) tools to study the extent of damage on the machined surfaces.

Journal ArticleDOI
TL;DR: In this paper, the results obtained with regard to grinding forces, specific energy, grinding zone temperature and surface residual stress when using cryogenic cooling and compares them to the results from dry grinding and grinding with soluble oil.

Journal ArticleDOI
TL;DR: In this paper, an approach to modeling the material removal rate (MRR) during rotary ultrasonic machining (RUM) of ceramics is proposed and applied to predicting the MRR for the case of magnesia stabilized zirconia.
Abstract: An approach to modeling the material removal rate (MRR) during rotary ultrasonic machining (RUM) of ceramics is proposed and applied to predicting the MRR for the case of magnesia stabilized zirconia. The model, a first attempt at predicting the MRR in RUM, is based on the assumption that brittle fracture is the primary mechanism of material removal. To justify this assumption, a model parameter (which models the ratio of the fractured volume to the indented volume of a single diamond particle) is shown to be invariant for most machining conditions. The model is mechanistic in the sense that this parameter can be observed experimentally from a few experiments for a particular material and then used in prediction of MRR over a wide range of process parameters. This is demonstrated for magnesia stabilized zirconia, where very good predictions are obtained using an estimate of this single parameter. On the basis of this model, relations between the material removal rate and the controllable machining parameters are deduced. These relationships agree well with the trends observed by experimental observations made by other investigators

Journal ArticleDOI
TL;DR: In this article, a wurtzite boron nitride (wBN)-cBN composite tool was used to machine titanium alloys, and the mechanisms controlling the wear of the cutting tool have been found to be similar to those observed in polycrystalline diamond (PCD) and polyCrystalstalline cubic Boron Nitride (PCBN) tools.

Journal ArticleDOI
TL;DR: In this article, the most important application field of conventional and new coatings for cutting tools is summarized, and an overview of the latest industrial applications of different coating for dry and high speed machining is given.
Abstract: According to the sold value, 40% of all cutting tools are coated in industry today. This paper summarizes the most important application field of conventional and new coatings for cutting tools. There are two opposing development trends in the cutting industry today: (1) in dry machining the user wants to work without coolant to save the environment and production costs; (2) in high speed machining (HSC) the cutting parameters can be increased by a factor of 4–10. Aside from increasing productivity, multi-spindle heads can be replaced by one spindle, increasing the flexibility enormously. With both technologies much greater heat is produced than under normal cutting conditions. The cutting materials must have a high warm hardness and cannot work without a good heat isolation coating between the hot chips and the tool body. This paper gives an overview of the latest industrial applications of different coatings for dry and HSC cutting and characterizes the most important requirements of future coatings for cutting tools.

Journal ArticleDOI
TL;DR: In this article, a geometrical model to describe the cutting process by using ball end milling with a tilt angle is presented, based on which the wear process and optimized cutting conditions for high speed milling of free formed surfaces can be determined.

Journal ArticleDOI
TL;DR: In this paper, an interelectrode gap model for estimating machining parameters for the minimum gap size under the limit of electrolyte boiling was presented, and an on-line monitoring system based on this correlation was proposed for the PECM process.

Journal ArticleDOI
TL;DR: In this paper, a germanium surface and the chips produced from a single-point diamond turning process operated in the "ductile regime" have been analyzed by transmission electron microscopy and parallel electron-energy-loss spectroscopy.
Abstract: A germanium surface and the chips produced from a single-point diamond turning process operated in the “ductile regime” have been analyzed by transmission electron microscopy and parallel electron-energy-loss spectroscopy. Lack of fracture damage on the finished surface and continuous chip formation are indicative of a ductile removal process. Periodic thickness variations perpendicular to the machining direction also are observed on these chips and are identified as ductile shear lamellae. The chips consist of an amorphous, elemental germanium matrix containing varying amounts of microcrystalline germanium fragments. The relative orientation of machining marks and crystallographic fragment texture are used to position individual chips with respect to the initial angular cutting zone on the wafer. Chips with high fragment content correlate directly to cutting zones subject to the highest resolved tensile stress on cleavage planes. These findings are explained in the context of a high-pressure metallization (brittle-to-ductile) transformation with ductility limited by the onset of classical brittle fracture.

Journal ArticleDOI
TL;DR: In this article, a mathematical model is presented for predicting the residual stresses of alloy 2014-T6 caused by end-milling, where factors such as the cutting conditions (cutting speed, feed, and cutting depth) and the tool geometries (tool nose radius and flank wear) are considered.

Journal ArticleDOI
TL;DR: In this paper, a laser heating mechanism initiating the drilling process is examined, including conduction and convection effects and assuming a steady-state evaporation process, and the maximum temperature attained inside the material, nucleation, explosion process and drilling efficiency are predicted.
Abstract: A laser heating mechanism initiating the drilling process is examined. The study includes conduction and convection effects and assumes a steady-state evaporation process. This enables estimation of the limits of the Fourier theory in laser drilling applications. Using the model described in the analysis, maximum temperature attained inside the material, nucleation, explosion process and drilling efficiency are predicted. The results obtained from the present work for the vapor front velocity are compared to those obtained from previous experiments. In addition, a laser drilling experiment is carried out while monitoring the surface evaporation process. This enables correlation of the theoretical results with the experiments.

Journal ArticleDOI
Jeong-Du Kim1, Dong-Sik Kim1
TL;DR: The physics of the micro-cutting process at very small depths of cut (1 μm or less) is not well understood despite the successful development of ultra-precision machining technology as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, the machining efficiency of Nd:YAG laser, excimer laser and electrical discharge machining (EDM) has been analyzed for composite materials, and the defect of machining defects has been addressed.

Journal ArticleDOI
TL;DR: In this paper, a cutting process model addressing chip removal and edge ploughing mechanisms separately yet simultaneously is presented, which is readily applicable in an industrial setting, its coefficients have physical meaning, and it can be calibrated with a concise quantity of orthogonal cutting data.
Abstract: A cutting-process model addressing the chip removal and edge ploughing mechanisms separately yet simultaneously is presented. The model is developed such that it is readily applicable in an industrial setting, its coefficients have physical meaning, and it can be calibrated with a concise quantity of orthogonal cutting data. The total cutting and thrust forces are each the summation of its individual components acting on the rake face and clearance face. These components are calculated using the rake and effective clearance angles from the normal and friction forces acting on each of these tool surfaces. These normal and friction forces are calculated by the chip removal and edge ploughing portions of the model, respectively, using four empirical coefficients. To calculate the clearance face forces, the interference volume is required, the calculation of which is based on a geometrical representation of the clearance face interference region. This representation is characterized in part by the depth of tool penetration, which is influenced by thermal energy generation and is therefore determined using a fifth empirical model.