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Wire electrical discharge turning (WEDT) process was developed to generate cylindrical form on any electrically conductive material applied in aerospace and automotive industry. The mechanism of metal removal in WEDT process is by means of successive spark discharge. Each spark results in the formation of crater. In the present work, a new model is proposed to predict the erosion rate of each spark for a given discharge energy. A new method is proposed to measure the crater depth from 2D roughness profile of the machined component. The proposed model is validated by conducting experiments on AISI 4340 steel and the results obtained are presented in the paper. It is observed that the results are in close proximity with the experimental values at low discharge energy. The stochastic erosion mechanism of WEDT process is analyzed using scanning electron microscope images of spark eroded wire. Using the proposed model the erosion rate can be controlled and better surface characteristic of machined surface can be achieved. [ABSTRACT FROM AUTHOR]

In recent years, demand of titanium alloy (Ti6Al4V) in various industries especially aerospace industries drastically increased. Several exceptional properties of titanium alloy that contribute to its popularity include high compressive and tensile strength, fracture toughness oxidation resistance and high strength-to-weight ratio. However, due to these superior properties, titanium alloys are categorized as hard-to-machine materials. The drilling process is accounted for roughly 40%−60% of material removal processes of an aeronautical product. Drilling processes for titanium alloys are categorized into conventional method (twist drilling) and unconventional method (rotary ultrasonic machining [RUM] drilling, laser drilling and electron discharge machining [EDM] drilling). This research aims to identify mechanisms and limitations of each drilling method applicable on titanium alloys. In addition, processing parameters affecting performance measures of each drilling method are discussed. The main problem associated with conventional twist drilling is extreme processing temperature, resulting in rapid tool wear and extensive burrs formation. These issues cause the cost for titanium alloy drilling to be relatively high as compared with twist drilling of other materials. To minimize these issues, researchers have developed several unconventional drilling methods, aiming to minimize issues found in conventional twist drilling. [ABSTRACT FROM AUTHOR]

Centerless grinding is an abrasive machining process commonly used in the aerospace and automotive industries for shaping axisymmetric components that require a high dimensional accuracy and a smooth surface finish. For this high volume manufacturing operation, process parameters have historically been selected conservatively using machining data handbooks or on a trial-and-error basis according to operator experience without explicit consideration of how the selected settings affect the productivity or cost of the operation. To improve operation efficiency, a science-based approach for selecting the optimum process parameters must be developed to replace traditional industrial practices. In this article, a methodology combining several analytical and experimental techniques is presented for optimizing the key process parameters in plunge centerless grinding of Inconel 718 and Ti-6Al-4V superalloy fasteners in two phases: (i) modeling of process constraints using experimental design and statistical regression, and (ii) determination of optimum grinding conditions in the feasible operating region using a simulation algorithm based on classical machining economics theory. The results show that the implementation of optimum material removal rates can lead to an appreciable reduction in the cost of the operation while satisfying the constraints imposed on the machine tool and the workpiece quality. [ABSTRACT FROM PUBLISHER]

Rotor steel 26NiCrMoV145 has been widely employed in aerospace and power industry because of its unique properties. As to this new material that is used widely in important places, it is worth studying its machinability. An experiment and finite element (FE) simulation has been carried out to study the cutting forces, cutting temperature and tool wear mechanism during high speed dry turning of 26NiCrMoV145 using multilayer TiCN + Al2O3 coated carbide inserts. The orthogonal test was chosen and cutting forces were measured to validate the FE simulations. SEM analysis has been carried out on worn tools to determine the tool wear mechanism. Crater wear and coating peeling could be found at every cutting speed. Flank face wear appears smooth when cutting speed increases. Analyses of tool stress and temperature distribution during simulated cutting process were also taken out to help in understanding tool wear mechanism. At last, an optimization of the cutting conditions was suggested when considering material remove rate, cutting forces and tool wear. [ABSTRACT FROM AUTHOR]

5-axis milling operations are common in several industries such as aerospace, automotive and die/mold for machining of sculptured surfaces. In these operations, productivity, dimensional tolerance integrity and surface quality are of utmost importance. Part and tool deflections under high cutting forces may result in unacceptable part quality whereas using conservative cutting parameters results in decreased material removal rate. Process models can be used to determine the proper or optimal milling parameters for required quality with higher productivity. The majority of the existing milling models are for 3-axis operations, even the ones for ball-end mills. In this article, a complete geometry and force model are presented for 5-axis milling operations using ball-end mills. The effect of lead and tilt angles on the process geometry, cutter and workpiece engagement limits, scallop height, and milling forces are analyzed in detail. In addition, tool deflections and form errors are also formulated for 5-axis ball-end milling. The use of the model for selection of the process parameters such as lead and tilt angles that result in minimum cutting forces are also demonstrated. The model predictions for cutting forces and tool deflections are compared and verified by experimental results. [ABSTRACT FROM AUTHOR]

Inconel 718 is one of a family of nickel-based superalloys which are used extensively in the aerospace industry in the hot sections of gas turbine engines. The literature detailing the effects of varying operating parameters on tool life when machining nickel based superalloys is comprehensive, however, relatively little of this data refers to their effects on machined workpiece surface integrity. Greater knowledge of the effects of operating parameters on surface integrity is critical to the acceptance of new cutting tool materials, tool geometries, and strategies, especially by the aerospace industry. The article initially reviews prior work on the machinability and surface integrity achieved when turning Inconel 718. Following on from this a series of experiments evaluating the effects of varying cutting tool material, geometry, and operating parameters are detailed. [ABSTRACT FROM AUTHOR]