THE TECHNOLOGICAL QUALITY CONTROL OF STACK CUTTING BY WIRE ELECTRICAL DISCHARGE MACHINING

2016 ◽  
Vol 24 (05) ◽  
pp. 1750060 ◽  
Author(s):  
TIMUR RIZOVICH ABLYAZ ◽  
KARIM RAVILEVICH MURATOV

Electrical discharge machining (EDM) of a stack allows achieving high precision and quality of cut surfaces and, therefore, this method is indispensable for state-of-the-art mechanical engineering. The procedure of EDM is carried out with wire-cutting machines. The characterization of constructive parameters of a stack of material and applying of an efficient cutting regime are the most important preconditions providing high precision of EDM. The goal of this work is the improvement of quality and efficiency of wire electrical discharge machining (WEDM) technology by theoretical and experimental studies of the WEDM process. The subsequent development of theoretical and empirical models allowing for the calculation of the quality parameters of treated surfaces is realized. It is shown that the main characteristics of cut surfaces are the roughness, size precision, error profile and structure of a surface layer. For the first time, the regression dependencies between the main parameters of the WEDM process (pulse [Formula: see text]-time [Formula: see text], off-time [Formula: see text], the height of the stack and the physicomechanical properties of the cut materials are obtained. The experimental study of WEDM confirms the results of mathematical modeling. It is proved experimentally that at an interlayer gap higher than 0.1[Formula: see text]mm, the cutting process stability is decreasing whereas the probability of the electrode fracture is increasing. However, it is found that at [Formula: see text]s and [Formula: see text]s, a stable cutting regime leading to bundling of the stock materials made from steel 65Γ can be realized.

2012 ◽  
Vol 630 ◽  
pp. 114-120 ◽  
Author(s):  
Mamidala Ramulu ◽  
Mathew Spaulding ◽  
P. Laxminarayana

To improve strength to weight ratios, the fiber reinforced polymer composite materials are often used in conjunction with another material, like metals, to form hybrid structure. This paper reports the feasibility of using wire electrical discharge machining (WEDM) for cutting Titanium/Graphite Hybrid Composites (TiGr). Slit and slot cuts with WEDM process has been performed. Cutting times and process parameters were recorded, and cut surface characteristics were evaluated both with an optical and scanning electron microscopy (SEM). The results in terms of cutting time, workpiece material removal rate, and damage were presented and discussed. It was found that use of WEDM is possible for machining advanced hybrid metal composite laminates with appropriate machine settings.


Author(s):  
K H Ho ◽  
S T Newman ◽  
R D Allen

Over the last five years, a great deal of research effort has been concentrated on the development of a new data model ISO 14649, informally known as STEP-NC. It has been strongly argued that STEP-NC has huge implications on the integration of the computer-aided design/computer-aided process planning/computer-aided manufacture (CAD/CAPP/CAM) (CAx) systems, giving the opportunity to realize interoperable computer numerical control (CNC) manufacturing. This is largely owing to the data model, which provides the capability to revolutionize the current state of the art in CNC manufacturing by offering a bi-directional interface with a high-level description of the geometrical and manufacturing information. This paper provides a view of how these STEP-NC compliant information models can be used to support the wire electrical discharge machining (WEDM) CAD to the CNC process chain. The models are based on part 13 of the ISO 14649 standard, which is dedicated to the WEDM process, together with part 10 of the standard, which specifies the general machining information. The information models have been identified and their structures have been defined and modelled using the unified modelling language (UML). A STEP-NC compliant WEDM CAx prototype system, based on the Java and the object-oriented database management system (DBMS) ObjectStore, has been constructed with an example case study to demonstrate the information models.


2019 ◽  
Vol 12 (2) ◽  
pp. 107
Author(s):  
Fipka Bisono ◽  
Dhika Aditya P.

Wire electrical discharge machining(WEDM) banyak digunakan untuk proses pembuatan punch and dies. Dimana material yang digunakan memiliki tingkat kekerasan yang sangat tinggi. Parameter pemesinan yang kurang tepat dapat menyebabkan hasil pemotongan yang tidak optimal. Penelitian ini dilakukan untuk mengoptimalkan beberapa karakteristik hasil proses pemesinan secara serentak dengan cara mevariasikan variabel-variabel proses pemesinan WEDM. Karakteristik hasil proses yang diteliti antara lain adalah lebar pemotongan, kekasaran permukaan, dan tebal lapisan white layer. Proses pemesinan dilakukan pada material tool steel SKD 11. Arc on time, on time, open voltage dan servo voltage merupakan variabel-variabel proses yang akan divariasikan. Rancangan percobaan dilakukan menggunakan metode Taguchi dengan matriks ortogonal L18(21x33) dengan dua kali replikasi. Sedangkan langkah yang digunakan untuk mengoptimasi karakteristik hasil proses pemesinan yang diteliti secara serentak adalah menggunakan metode grey relational analysis (GRA). Lebar pemotongan, kekasaran permukaan dan tebal lapisan white layer memiliki performance characteristics “smaller-is-better.” Hasil dari penelitian menunjukkan nilai variabel-variabel proses pemesinan yang menghasilkan kualitas karakteristik yang paling optimum adalah sebagai berikut: arc on time (1A), on time (4?s), open voltage (70V), dan servo voltage (40V). Dengan persentase kontribusi variabel proses dari yang terbesar berturut-turut adalah on time (65,09%), open voltage (11,35%), arc on time (7,71%), dan servo voltage (5,61%). Wire electrical discharge machining (WEDM) process is commonly used to make punch and dies. WEDM services are typically used to cut hard metals. Inappropriate machining parameters can cause suboptimal cutting results. This research was conducted to optimize several characteristics of the machining process simultaneously by varying WEDM machining process variables. Performance characteristics of the WEDM process include the kerf, surface roughness and thickness of the white layer. The machining process is carried out on SKD 11 tool steel material.  Arc on time, on time, open voltage and servo voltage are process variables that will be varied. The experimental matrix design was carried out using the Taguchi method L18 (21x33) orthogonal array with two replications. Then to optimize the performance characteristics of the machining process simultaneously is using the Gray Relational Analysis (GRA) method. Performance characteristics of kerf, surface roughness, and thickness of the white layer is "smaller-is-better". The results of the experiment indicate the value of the machining process variables that produce the most optimum quality performance characteristics are as follows: arc on time (1A), on time (4?s), open voltage (70V), and servo voltage (40V). And the percentage of contribution of the process variables from the largest to smallest are as follows: on time (65,09%), open voltage (11,35%), arc on time (7,71%), and servo voltage (5,61%).


Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 454 ◽  
Author(s):  
Arkadeb Mukhopadhyay ◽  
Tapan Barman ◽  
Prasanta Sahoo ◽  
J. Davim

To achieve enhanced surface characteristics in wire electrical discharge machining (WEDM), the present work reports the use of an artificial neural network (ANN) combined with a genetic algorithm (GA) for the correlation and optimization of WEDM process parameters. The parameters considered are the discharge current, voltage, pulse-on time, and pulse-off time, while the response is fractal dimension. The usefulness of fractal dimension to characterize a machined surface lies in the fact that it is independent of the resolution of the instrument or length scales. Experiments were carried out based on a rotatable central composite design. A feed-forward ANN architecture trained using the Levenberg-Marquardt (L-M) back-propagation algorithm has been used to model the complex relationship between WEDM process parameters and fractal dimension. After several trials, 4-3-3-1 neural network architecture has been found to predict the fractal dimension with reasonable accuracy, having an overall R-value of 0.97. Furthermore, the genetic algorithm (GA) has been used to predict the optimal combination of machining parameters to achieve a higher fractal dimension. The predicted optimal condition is seen to be in close agreement with experimental results. Scanning electron micrography of the machined surface reveals that the combined ANN-GA method can significantly improve the surface texture produced from WEDM by reducing the formation of re-solidified globules.


2016 ◽  
Vol 15 (02) ◽  
pp. 85-100 ◽  
Author(s):  
P. C. Padhi ◽  
S. S. Mahapatra ◽  
S. N. Yadav ◽  
D. K. Tripathy

The present work is aimed at optimizing the cutting rate (CR), surface roughness (Ra) and dimensional deviation (DD) in wire electrical discharge machining (WEDM) of EN-31 steel considering various input parameters such as pulse-on-time, pulse-off-time, wire tension, spark gap set voltage and servo feed. A face centered central composite design of response surface methodology (RSM) has been adopted to develop the empirical model for the responses. It is often desired to obtain a single parameter setting that can decrease Ra and DD and increase CR simultaneously. Since the responses are conflicting in nature, it is difficult to obtain a single combination of cutting parameters satisfying all the objectives in any one solution. The optimum search of the machining parameter values for maximization of CR and minimization of Ra and DD are formulated as a multi-objective, multi-variable, nonlinear optimization problem using genetic algorithm weighted sum method to evaluate the performance.


2012 ◽  
Vol 507 ◽  
pp. 180-183 ◽  
Author(s):  
Cun Shan Xu

Wire electrical discharge machining (WEDM) is an advanced thermal machining process capable of accurately machining parts with complicated shapes, especially for the parts that are very difficult to be machined by traditional machining processes. WEDM process is based on the conventional EDM sparking phenomenon utilizing the widely accepted non-contact technique of material removal. Since the introduction of the process, WEDM has evolved from a simple means of making tools and dies to the best alternative of producing micro-scale parts with the highest degree of dimensional accuracy and surface finish quality. This author reviews the vast array of research work carried out from the EDM process to the development of the WEDM, also highlights the working principle and mechanical performance of machining conditions. A wide range of WEDM industrial applications are reported together with the development of the hybrid machining processes. The final part of the paper discusses these developments and outlines the possible trends for future WEDM research.


Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3359 ◽  
Author(s):  
Jun Wang ◽  
Jose Sanchez ◽  
Izaro Ayesta ◽  
Jon Iturrioz

Manufacturing more efficient low pressure turbines has become a topic of primary importance for aerospace companies. Specifically, wire electrical discharge machining of disc turbine fir-tree slots has attracted increasing interest in recent years. However, important issues must be still addressed for optimum application of the WEDM process for fir-tree slot production. The current work presents a novel approach for tolerance monitoring based on unsupervised machine learning methods using distribution of ionization time as a variable. The need for time-consuming experiments to set-up threshold values of the monitoring signal is avoided by using K-means and hierarchical clustering. The developments have been tested in the WEDM of a generic fir-tree slot under industrial conditions. Results show that 100% of the zones classified into Clusters 1 and 2 are related to short-circuit situations. Further, 100% of the zones classified in Clusters 3 and 5 lie within the tolerance band of ±15 μm. Finally, the 9 regions classified in Cluster 4 correspond to situations in which the wire is moving too far away from the part surface. These results are strongly in accord with tolerance distribution as measured by a coordinate measuring machine.


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