Papers by Keyword: Kerf

Abstract: Micro dry wire EDM is a process where gas is used as the dielectric fluid instead of a liquid. In this process certain modifications of a wire EDM are needed during the machining operation to achieve stable machining. Optimizing kerf to get high dimensional accuracy is one of the critical issues in micro dry wire EDM. The fundamental modelling for optimum kerf using micro dry wire EDM has not been formulated yet. Due to the complex phenomenon, the prediction of optimum kerf in a micro dry wire EDM process is rather difficult. Hence, the main objectives of this research are to improve the micro dry wire EDM process and to develop mathematical models for optimum kerf using micro dry wire EDM. During the process improvement of micro dry wire EDM, various machining setup will be involve in order to achieve the most stable process. The most stable machining process will be used to prove the developed mathematical models. A mathematical relationship between kerf and process parameters is anticipated. The mathematical models in conjunction with experimental data will eventually produce the desired theory. The developed process and mathematical model of kerf is a breakthrough in fabricating products such as micro tools, molds etc. with optimum kerf and high dimensional accuracy. The successful completion of this research will contribute to the environmental friendly micromachining process.

Abstract: Nimonic-80A is a nickel based super alloy which is specifically used in aerospace industry for its high strength to weight ratio and corrosion resistance. This paper presents the influence of process parameters of wire cut Electrical Discharge Machining (WEDM) during the machining of Nimonic 80A with brass wire as electrode and optimization of machining parameters on kerf width. Process parameters (pulse-on time, pulse-off time, peak current, spark gap set voltage, wire feed and wire tension) have been investigated using L₂₇ orthogonal array. With the assistance of Taguchi quality design, ANOVA and F-test, significant parameters affecting the kerf have been identified. The surface topography of machined samples has been studied in correlation with the rate of input energy into the spark.

Abstract: This paper proposed a response surface methodology technique to optimize the multi-response of wire-cut electric discharge machining process. The machining was done on Al 6063 plate is casted with varying mass of Al₂O₃ (3%, 6%, 9%). Stir casting process is adopted for casting the composite plate. Design Expert is used to identify the effect of key operating factors on output measures such as surface finish and kerf by using Pulse on-time, pulse off-time, servo feed and varying mass of Al₂O₃ (3%, 6%, 9%). Also the distribution of Alumina and Aluminium is examined by microstructure analysis, and the material is tested for its mechanical Properties such as tensile strength and Hardness. We found that with respect to increase in pulse on-time and weight percentage of alumina the Surface roughness and kerf decreased leaving a better finish. Also a comparison has been done between the result obtained through response surface methodology and experimental values which indicates that the experimental values are very much close to the predicted values.

Abstract: The current trend in abrasive water jet machining process is getting focused on milling applications using this technique. Abrasive water jet machining (AWJM) process is a well defined process for cutting or part separation. The present paper reports on the geometry obtained in controlled depth milling process of different materials. The dimensions considered in this paper are the pocket depth and the change in the kerf profile. Experimental observations are made relating the kerf profile with traverse speed and the mechanical properties of the work piece material. Tool paths for obtaining the pocket of size 9 mm x 20 mm are generated in raster mode and machined using AWJM on materials of varying hardness and at different traverse speeds. It is observed that there is a significant change in the geometry of the kerf profile and also the depth of the pocket with speed in conjuction with the material hardness.

Abstract: This paper presents the estimation of kerf width in micro wire electrical discharge machining (micro WEDM) in terms of machining parameters of capacitance and gap voltage. An empirical model is developed by the analysis of variance (ANOVA) of experimental data. Using a wire electrode of 70 µm diameter, a minimum kerf width is found to be 92 µm for the micro WEDM parameters of 0.01 µF capacitance and 90.25 V gap voltage. Around 30% increament of the kerf is found to be high. The analysis also revealed that the capacitance is more influential parameter than gap voltage on kerf width produced by micro WEDM. As the gap voltage determines the breakdown distance and affects the wire vibration, the wire vibration factor is to be considered in the analysis and in formulation of model in future study.

Abstract: Micro abrasive air jet (MAAJ) cutting is a promising technology for the fabrication of three-dimensional microstructures in hard and brittle materials. In this paper, a study on the cross-sectional shape of the kerf cut with MAAJ is presented. It shows that the machining depth and slope of the sidewall increase with an increase in air pressure, abrasive flow rate and jet incidence angle, while decrease with an increase in nozzle traverse speed. Using a dimensional analysis technique, predictive model for cross-sectional profile is developed. The research results may be meaningful to the highly precision three-dimensional micro-structural cutting.

Abstract: In Micro Wire Electrical Discharge Machining (Micro-WEDM), the kerf width varies with different machining parameters, which will greatly influence the machining precision. In order to study the kerf variations in Micro-WEDM, the influence of kerf variation is analyzed and the experiment considering the kerf width and machining speed are performed on self-developed micro-WEDM under different machining parameters. With the reference of the experiment results, 32μm wide slot is machined with Φ30μm wire-tool on stainless steel workpiece.

Abstract: The effects of following four factors, which are laser power, assist gas pressure, cooling rate and scanning speed on the quality characteristics of laser cut 316L stainless steel tubes have been studied. 24 full factorial design and central composite design were used to evaluate optimum condition of process parameters. Regression analysis was used to develop empirical models for the combined effects of the independent process parameters on laser cut quality. As the results, it was observed that laser power, assist gas pressure and scanning speeds did the major effects on kerf width. The smallest kerf width was obtained with the condition of low laser power, assist gas pressure, scanning speed and moderate cooling rate. Calculated regression model was kerf width = 64.47 + 0.91W + 1.25P + 0.41S + 0.41C2 - 0.45P2