Papers by Keyword: Wire Electrical Discharge Machining

Abstract: The stretch flangeability of ferritic steel grade with tensile strength ≥1 GPa in hole expansion tests can be significantly improved by using the wire electrical discharge machining (W-EDM) process for hole-making instead of conventional punching tools. This improvement is attributed to the notably enhanced cut edge quality of the machined holes. In this study, the average hole expansion ratio (HER) of a novel 0.1C-0.3V-0.25Mo-0.08Ti-0.08Nb steel increased from 24% to 91% when W-EDM was used in hole preparation. A comparison between the fractured surfaces of punched and W-EDM-machined holes after HER testing revealed different failure mechanisms in the steel sheet. At the onset of cracking, fractures in the W-EDM specimens exhibited ductile behavior, whereas quasi-cleavage fracture was observed in the punched specimens. Based on texture measurements and metallographic investigations, it was concluded that reducing the intensity of the adverse shear texture component {112}<111> near the steel sheet surface and eliminating microstructural constituent variations improved the stretch flangeability of the Ti-Mo-V-Nb steel in both hole-making processes.

Abstract: New technologies known as unconventional technologies make it possible to cut complex shapes at high speed and with relatively high precision. In many cases, especially in the case of thin sheet, created parts produced do not require any further treatment by post-machining. Knowledge of the accompanying phenomena, such as the heat-affected zone (HAZ) or the surface quality of the cutting edge, is necessary, for example, to assess further machining of material in these areas (e.g. drilling and reaming holes or finishing operations on the cutting edge). In this study, the thermal effect of four unconventional cutting technologies – laser, plasma, wire electrical discharge machining (wire EDM) and waterjet cutting on the cut surface of steel sheets is investigated. Steel 1.7102 (DIN 54SiCr6) was chosen for purpose of this study. The width of the HAZ and the nanohardness beneath the cut surface were analyzed.

Abstract: Newly developed D2 steel is widely used for various advanced engineering applications. Machining of D2 steel to obtain desired quality responses has immense importance for the effective utilization of these materials for advanced industrial applications like aerospace, marine, automobile, etc. Wire electrical discharge machining (WEDM) is used to machine difficult to machine materials and to produce sophisticated features with better dimensional accuracy. Obtaining the fine surface roughness in WEDM has highly depends on correct selection of process parameters. In the present work, experimental investigation was planned to study the effects of WEDM input parameters on surface roughness (R_a) of D2 steel. Experimental runs were conducted by using L₁₆ orthogonal array of Taguchi method. The analysis of variance was employed to determine the influences of process parameters on R_a. Response surface methodology (RSM) and cuckoo search optimization (CSO) algorithm had been used to model and optimize the surface roughness. From the study, it was found that R_a value had improved as compared to initial experimental runs.

Abstract: Wire electrical discharge machine (WEDM) is non-conventional machining process. It can be used for hard cutting material. The study has been presented the combining WEDM with an ultrasonic machine (USM) with brass and tungsten were used as a wire electrode and workpiece respectively. The experiment was carried out with an ultrasonic transducer at 40, 80 kHz. The results were observed with the material removal rate (MRR) and surface roughness (Ra). This research introduced the method of USM setup and described the effected of vibration with the wire electrode on the displacement of amplitude. The result shows that the WEDM process with USM at 40 kHz can be more improved with the material removal rate and surface roughness than that of USM at 80 kHz. This can be explained that higher frequency affected to vibration displacement which makes lower amplitude.

Abstract: Owing to the fact that conventional Taguchi methods cannot predict the experimentresults of non-level values, this study developed a staged Taguchi neural network prediction modelthat combines the merits of experimental data from the Taguchi method and the learningcapabilities of artificial neural networks. We first used the optimal parameter combinations derivedfrom the L9 orthogonal array experiment data and grey relational analysis as training examples forthe Stage-1 network to construct a preliminary network. Next, we used the crucial factors in theoptimal parameter combinations derived from the grey relational analysis as additional trainingexamples for the Stage-2 network. The results of the staged Taguchi neural network predictionmodel indicate that the prediction performance of the preliminary network in Stage 1 was poor dueto an insufficient number of training examples, while the Stage-2 network produced excellentprediction results.

Abstract: Powder metallurgical high speed steel (such as S390) has superior mechanical properties and been used as fineblanking tools. The electrical discharge machining has been widely used for cutting fine blanking tools which are made of especially hard tool steels. Whereas, its thermal nature causes great concerns regarding surface integrity, which matters a lot to tool life. In the present study, the evolution of surface integrity of the S390 with multi-cutting is comprehensively compared. The result shows that the surface roughness, white layer thickness and surface residual stress decrease with the increase of cutting pass. Additionally, the effectiveness to remove white layer on HSS S390 by manual and towed polishing and electrolytic polishing are compared. At last, a device of abrasive water jet polishing is designated to remove the white layer resulted from wire-cutting.

Abstract: In this investigation, a new approach is based on Grey Relational Analysis and Taguchi method to optimize the machining parameters with multi performance characteristics in WEDM of 304L SS. Experiments are conducted using Taguchi Quality Concept, L₉,3-level orthogonal array was chosen for experiments .The WEDM parameters namely pulse-on time (T_ON), pulse-off time (T_OFF), and wire feed (WF) on material removal rate (MRR) .The Grey Relational Analysis with multiple performance characteristics indicates that the pulse-on time (T_ON), pulse-off time (T_OFF) are the most significant factors . The optimum machining parameters have been identified by Grey relational analysis and significant contribution of parameters can be determined by analysis of variance (ANOVA). The confirmation test is also conducted to validate the test result. The results from this study will be useful for manufacturing engineers to select appropriate WEDM process parameters to machine 304L Stainless Steel.

Abstract: In this article, the effect of wire electrical discharge machining (WEDM) parameters such as pulse-on time (T_ON), pulse-off time (T_OFF), and wire feed (F) on material removal rate (MRR) and surface roughness in metal matrix composites (MMCs) consisting of aluminium alloy (A1356) silicon carbide (SiCp) and Mica is discussed. The Al 356 is reinforced with SiCp and Mica in the form of particulates. The experiments are carried out as per design of experiments approach using L9 orthogonal array. The optimum machining parameters have been identified by a composite desirability value obtained from desirability function analysis as the performance index, and significant contribution of parameters can then be determined by analysis of variance (ANOVA). Confirmation test is also conducted to validate the test result. Experimental results have shown that machining performance can be improved effectively through this approach. The results were analysed using analysis of variance and response graphs. It is found that different combinations of WEDM process parameters are required to achieve higher MRR and minimum surface roughness for composites. These results will be useful for manufacturing engineers to select appropriate WEDM process parameters to machine MMCs of Al 356 reinforced with SiC and Mica.

Abstract: Wire electrical discharge machining is nowadays applied by using adequate specialized machine tools. A research problem could refer to a device for wire electrical discharge machining, adaptable on the current computer numerical controlled ram electrical discharge machines. The device could be able to be used in order to develop cutting processes in plate type workpieces. The wire electrical discharge machining process was examined and premises for developing a device for wire electrical discharge machining were formulated. These premises are used in order to develop an ideas diagram able to offer suggestions for the structure of the device. Distinct components necessary in the device structure were identified and taken into consideration, and three distinct versions of the device were defined.

Abstract: In this research, a heat pipe with grooves was experimentally analyzed for the application in thermal management of electronic packaging. The heat pipe was produced by a copper tube with an outer diameter of 9.45 mm, length of 205 mm, and capillary structure composed by axial grooves with average diameter of 220 μm. The grooves were manufactured using wire electrical discharge machining (wire-EDM). The working fluid used was de-ionized water. The condenser was cooled by air forced convection and the evaporator was heated using an electrical resistor. This heat pipe was tested horizontally to increasing heat loads varying from 5 to 15 W. The experimental results showed that the heat pipe worked successfully.