EDM Electrodes Research Articles

English

English

PERFORMANCE ENHANCEMENT OF BRASS EDM ELECTRODES WITH CRYOGENIC TREATMENT WHILE MACHINING THE COLD WORK STEEL AISI D2

This study investigates the performance of deep cryogenically treated brass (CuZn25Al5) electrodes in the die-sink EDM process. Two different cryogenic treatment durations, 6 h and 12 h, were applied to 8 mm diameter electrodes, and their effects were compared to untreated electrodes. The machining tests were conducted under moderate and aggressive conditions. In the machining tests, the 6-h cryo-treated electrode exhibited a 16.8% increase in material removal rate (MRR) under moderate conditions and a 19.7% increase under aggressive conditions compared to the reference electrode. The 12-h cryo-treated electrode showed similar MRR values to the reference electrode but improved tool wear resistance by 9.4% under moderate conditions. The kerf angle was minimized, indicating better hole verticality, in the 6-h cryo-treated electrode group. The improvement in machining performance was attributed to the enhancement in electrical conductivity of the electrodes, which increased by 28% for the 6-h cryo-treated electrode and 20% for the 12-h cryo-treated electrode. X-ray diffraction (XRD) analysis revealed shifts in peak positions and possible phase transformations due to cryogenic treatment. Surface roughness measurements showed improved surface conditions in the cryo-treated electrodes under aggressive conditions. The results indicate that cryogenic treatment enhances MRR, reduces tool wear, and improves surface quality in die-sink EDM. These improvements are attributed to increased electrical conductivity and changes in the internal structure of the brass electrode.

Automatic evaluation of EDM electrode wear via integration of image segmentation and 3D registration (IS-3DR)

Automatic evaluation of EDM electrode wear via integration of image segmentation and 3D registration (IS-3DR)

Experimental and Multi-Optimization Investigation of Machining (X210) Alloy Steel Using Angled EDM Electrodes

Experimental and Multi-Optimization Investigation of Machining (X210) Alloy Steel Using Angled EDM Electrodes

Metrological Assessment of Microtextured EDM Electrodes Generated by Additive Manufacturing and Electroforming

Surface engineering makes use of functional and aesthetic textures to meet different needs in the development of new products, with high-value enriched features. At present, the use of additive manufacturing is bringing many advantages in its integration into advanced hybrid manufacturing processes. The direct application of textures on 3D models is a viable, fast and sustainable solution in many of these technologies by reducing the consumption of resources in materials and energy, of the additional processes that have been commonly applied in these applications.One of the processes that allows texturization of materials with great hardness is sinker electro discharge machining. This process, although slow, allows to obtain textures in small dimensions with very high precision, difficult to achieve by conventional processes. However, one of the aspects that make it a slow and expensive process is the manufacture of electrodes, especially those with complex geometries.Therefore, work is being done to solve this aspect, combining the additive technology of stereolithography by mask (MSLA) and the electroforming process to generate micro-textured copper electrodes with some structured and bioinspired textures. The model parts are generated with the textures in MSLA, which are then metallized on the functional surfaces before being introduced into the electrolytic bath to generate the electroforms with the appropriate thickness. This work presents the results of the metrological assessment from he CAD modeling to the electroeroded part, including the generated model part and the electrode made from it. This work is being developed in the Integrated and Advanced Manufacturing research group of the University of Las Palmas de Gran Canaria and in collaboration with the Engineering and Materials and Manufacturing Technology research group of the University of Cadiz.

Experimental analysis of SS316 using brass electrode in electric discharge machining

The current work is directing an exploratory study of EDM on SS316 using brass metal as the electrode. Copper and zinc are combined to form the alloy known as brass. Small tubular electrodes are made of brass materials. Brass is significantly simpler to process, but it does not have the same wear rate as copper or tungsten. Because new material may be introduced continually all across the EDM machining process, the EDM electrodes need not be resistant to wear or arc erosion.These uses current, pulse on time and pulse off time as input parameters. Gap voltage, dielectric, and cutting depth were fixed parameters in the experiments performed. The resulting observations are material removal rate, tool wear rate, and surface roughness determined to quantify the occurrence of EDM. To collect and evaluate the impact of various process parameters to improve response variables such as material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) according to the three level and three variable (L9) Taguchi orthogonal matrix.

A study in EDM electrode manufacturing using additive manufacturing

Electrode can be manufacture by conventional as well as non-conventional processes like Thermal spraying and Additive manufacturing (AM). In AM mostly Fused Deposition Modeling (FDM) and Laser Sintering (LS) are used. The selection of a proper manufacturing process has a very vital role when it comes to output characteristics of Electrodes. In this paper Authors have reviewed LS and FDM based EDM tool manufacturing processes. The purpose of this study is to present significant findings about effective EDM electrode manufacturing using LS and FDM. It was concluded that, the RP made tool electrode can be used where higher surface finish are desired and MRR and TWR can be neglected. The electrode manufactured using FDM techniques promising results for rough cutting and semi-finishing cut in EDM operations.

Influence of Cryogenic Behaviour on Copper Electrode for Non-Conventional EDM

In the last few decades, non-traditional machining has increased the efficiency of the machining process. One of the most prevalent non-traditional methods of milling is through the use of an EDM process. Traditional machining methods can't easily machine materials with a complicated profile or hardness that EDM can handle. The industrial sector makes extensive use of EDM. Cryogenically treated copper electrodes and regular copper electrodes were used to conduct an experiment on an EN24 material using varied input parameters, such as electrode rotation, gap voltage, and discharge current. Electric discharge machining was used in a study. The Taguchi method is used to design experiments. Three input parameters were employed in an orthogonal L16 array to find an optimal value for each of the three components. OC (overcut), TWR (Tool wear rate), and Ra (surface roughness) are the three output variables. The S/N ratio can be used to determine the best values and relative relevance of each of these factors using a statistical analysis of variance (ANOVA) table. Additionally, the overcut, tool wear rate, and surface roughness of traditional and non-traditional EDM are examined. For the deep cryogenic and non-traditional machining method, conventional and non-traditional electric discharge machining methods were found to have optimal or dominant factors for the TWR and Ra.

Software based analysis of angularity error for polygonal micro-cavities produced by die-sinking EDM

This paper aims to present the results of an investigation on the angularity error calculated for micro polygonal cavities i.e. triangular, square, pentagonal and hexagonal cavities. The investigation began by machining of micro polygonal shapes in series of three on steel sample using 400 µm tungsten carbide electrode in die-sinking EDM integrated with e-pulse supply and précised multi-axes electrode movement enabling micro-machining capabilities. After that the machined micro-cavities and their geometry were examined by an Olympus optical microscope and the accuracy of shapes has been evaluated after analyzing angularity error of these geometries by profile projector and olympus analysis five software. It was found that the average angularity error of triangular micro cavities is 4.34° while that for square, pentagonal and hexagonal micro cavities are 1.33°, 7.93° and 8.74° respectively. On the basis of obtained data, it is found that the square cavities have maximum angular accuracy as compared to others. It may be attributed to the fact that there is lesser presence of secondary discharge in case of square cavities and limited tool travel.

Machinability study of Incoloy using different wire electrode in Wire-Cut EDM

Increase in the usage of nickel-based superalloys in the field of aviation, marine industry, nuclear reactor due to its excellent mechanical properties like corrosive resistance, carburization resistance especially at elevated temperature. Nickel based superalloys are very tedious to machine in conventional because of high strength, less conductivity of thermal, strain hardening property. In this study, one of the best Unconventional machining processes i.e., Wire electric discharge machining is used for machining of Inconel 800 (Incoloy). Zinc coated brass wire; Cryogenic cooled zinc coated brass wire electrodes are used in Wire cut EDM. RSM technique is used to plan experiments with Wire tension, Pulse on time and Wire feed as varying parameters, keeping Servo voltage and Wire feed as constant. Material removal and Roughness of surface are compared for Zinc treated brass and Cryogenic cooled (LN2) Zinc treated brass and optimizing responses i.e., by using lower the better and higher the better criteria.

Interaction between copper and thermally expanded graphite during mechanical alloying and spark plasma sintering

Copper and graphite currently serve as electrical engineering materials. For example, either can be used to make electrodes and contacts. Composite materials (including copper-graphite composites) offer better performance — i.e. relative electroerosion resistance and productivity. However, the scope of their application is limited and further research into them is necessary. This research aims to examine the effect of mechanical alloying of the copper – themally expanded graphite powder system followed by spark plasma sintering on the structure of particles and materials and on their physico-mechanical properties. The experimental study into the structure and properties of composite powder materials involved using the methods of X-ray phase analysis, Raman spectroscopy, atomic-force spectroscopy, metallography, spark machining, etc. Powders of high-conductivity copper PMS-1 (per GOST 49-60–75) and thermally expanded graphite produced by Novomet-Sealur were used to make the composite materials. The compositions included 1 wt. % (4 vol. %) of graphite. The process involved mechanical alloying for 1, 2 and 3 hours in a SAND planetary mill (Russia) with the powder-to-balls weight ratio of 1:25. The process resulted in the structural breakdown of graphite and the formation of solid solutions of carbon in copper. Following the process of spark plasma sintering in a Dr. Sinter SPS-1050 unit (Japan) at 900 oС, the latter experienced partial decomposition. This paper demonstrates the role of copper in the restoring of graphite structure during mechanical alloying. Copper-based materials have been developed which have lower electrical resistivity than copper. Intercalates formed in graphite may serve as one of probable mechanisms for decreasing the electrical resistivity. A larger copper-graphite phase contat area and a higher deformation degree of graphite during mechanical alloying lead to higher electrical resistivity in composite materials. A correlation was established between the relative spark erosion wear and the electrical resistivity in copper-graphite composite materials. Thus, the relative spark erosion wear of the best compositions was 20–30% lower than in the case of cast copper M1. The feasibility of using copper-graphite EDM electrodes can be reached due to reduced cost of the EDM electrodes that offer high wear resistance combined with higher performance.This research was funded by the Ministry of Education and Science of Russia under the programme of the World-Class Science & Education Centre Rational Use of Mineral Resources.

Significant complications declining usage of Electrical Discharge Machining process

In the present paper, an effort has been laid down to develop a framework for the micro EDM (μ EDM) in today’s industrial environment. The μ EDM has shown considerable involvement in ceramic industries where workpiece needs to be machined in micro sizes. μ-EDM owing to stronger surface quality and higher precision is a futuristic machining process for building up micro tools and alternative micro components. However, there are several complications that demand to be discussed before μ-EDM can be dealt with as a decisive technique and it can carry out its performance. This investigation includes of the EDM system scheduling and electrode wear issues. Particular consideration has been offered to aspects and methods critically varying the efficiency involving positioning approaches during grinding of electrode and new μ-EDM operations.

Retraction Note: Development and application of copper–nickel zirconium diboride as EDM electrodes manufactured by selective laser sintering

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1007/s00170-020-06547-5

Experimental Investigation of Uncoated Electrode and PVD AlCrNi Coating on Surface Roughness in Electrical Discharge Machining of Ti-6Al-4V

The surface texture on the EDM is an important quality indicator since it directly affects the cost of the further finishing work. The coating over the tool electrode in EDM can improve productivity, electrode wear resistance and surface quality. In the present study, the surface roughness of the EDM machined surface with coated and uncoated electrodes was evaluated. Al and AlCrNi coated Al electrode has been used for the study on machining Titanium alloy (Ti-6Al-4V). Current (I), voltage (Vg) and pulse on time (Ton) have been used as technology parameters under Taguchi method with regression model and optimal technology parameters. It was found as I and Vg are the parameters could strongly affect surface quality. The coated tool electrode can produce better surface quality than uncoated tool electrode. The optimal technological parameters with coated and uncoated electrodes were found as I = 10 A, Ton = 500 µs and Vg = 40 V.

Optimization of EDM Electrode by Direct Metal Laser Sintering (DMLS) method for SS316L Material

EDM is one of the methods used in processing. It is a process in which the eroded material starts from the piece with the aid of a series of sparks to obtain the desired shape. It is useful for processing hard metals. The work done by several researchers helps in producing EDM electrodes through SLS, as a different method to conventional processing techniques, and to assess the action of electrodes produced with the technique. Due to this reason, experimental research is carried by SLS out on electrodes made from brass, copper alloy and nickel alloy of bronze and nickel, and steel alloy disintegration of a solid substance. EDM recital is evaluated in terms of material deposition (Vw), which represents the volume of extract from the piece per unit of time (cubic meters per second) and correlative magnitude wear (θ), which shows the relationship between the rate of electrode wear and the rate of material withdrawn. A comparative study between the electrodes produced by SLS and the electrodes made in a conventional manner with respect to SS316L material is made.

The analysis of EDM electrodes wear in corners and edges

Die-sinking electrical discharge machining is an unconventional technology that allows to machine all at least minimally electrically conductive materials regardless of their physical and mechanical properties. Despite the fact that it is not a conventional technology, the tool gets also worn out, which is a tool electrode. The wear of the electrode does not only mean its loss but also the degradation of the shapes that are transferred to the resulting workpiece. For this reason, a design of experiments was conducted with 6 input factors, 2 were categorical: the electrode material (copper, graphite) and workpiece material (steel 1.2363 and steel 1.2343ESR) and 4 were numerical: Open-voltage, Pulse current, Pulse on-time, and Pulse off-time. In the framework of this design of experiments, the wear of the used graphite and copper electrodes at their corners and edges was evaluated, which was made possible by the use of electron microscopy and the use of approximation circles. Furthermore, the eroding speed, the topography of the machined samples, and the morphology of the surfaces of the used electrodes were investigated. It has been recognized that the use of a graphite electrode will allow for more accurate workpiece shapes and less wear.

Optimization of electrochemical etching process for manufacturing of micro electrodes for micro-EDM application

Application of Micro-Nano scale Electrical Discharge Machining is rapidly growing in manufacturing of metal products irrespective of its hardness having geometric features in range of micrometer to nanometer scale. To achieve such small geometrical features, smaller dimensional tool electrode is required. However fabrication of this tiny electrode with desired dimension and also handling of such tiny electrodes is a primary aspect that needs to be investigated systematically to use the Micro-Nano scale EDM in batch production of micro parts. In this work authors investigate the application of electrochemical etching process for fabricating EDM electrodes smaller than 10 µm. While the smallest electrode fabricated with the optimized parameter is 3.33 µm, their performance as electrode in micro-EDM has been studied systematically. To the best of authors’ knowledge such studies are not reported in the published literatures. However, the fabrication of such smaller size features by applying alternating current in ECE has been attempted previously but not for micro-EDM applications.

Development of the Technology for Manufacturing a Combination EDM Electrode by Rapid Prototyping

Purpose of research is to develop a methodology that allows designing EDM electrodes applying advanced computer-aided design (CAD) systems by forming the tool’s working surface with geometry which is inverse equidistant to the geometry of a given workpiece taking into account the EDM gap, working translation or translation-rotational motion of EDM electrodes, the value of the layer of conductive coating based on the technological parameters of the processing procedure. It is also necessary to propose, implement and formulate technological guidelines for manufacturing EDM electrodes from dielectric materials by additive techniques with the subsequent formation of a conductive layer on them; the value of the layer should ensure the flow of working electrical processes in the EDM gap and the necessary tool life. This will make it possible to expand the scope of application of combination EDM electrodes as applied to combined processing techniques which are characterized by a wide variety of working surface shapes, which correspond to the geometry of the workpiece, which is not limited by the degree of curvature, has by far lower cost and high processability when creating a special tool for pilot and single manufacturing.Methods. When carrying out the work, theory of the classical laws of mechanical engineering technology, electrical processing techniques, the known laws of rapid prototyping and additive technologies were used.Results. The theoretical foundations and the technology for manufacturing combination EDM electrodes by rapid prototyping have been developed and a methodology for calculating and designing the working part of EDM electrodes has been proposed taking into account the geometric parameters of the machined surface and a variable EDM gap value.Conclusion. The mechanism of EDM electrode design by means of digital prototyping in modern CAD systems is justified taking into account the features of the workpiece geometry, EDM gap and metallization material.

Fabrication Study of Cu-C-Ni for EDM Electrode by a Sintering Technique

The aim of this research was to study the feasibility for applications related to powder metallurgy in EDM electrode fabrication by combination of the percentage Cu-C-Ni element. The experiment was performed by comparing preliminary distribution results of particle size before and after the grinding of metal powders. The work-piece was pressed at a pressure of 200 Psi using a uniaxial press machine. The pressed green compact work-piece was then baked in a furnace. The gas inside the furnace that was used to control the temperature during the cold press procedure had a mixture gas ratio between argon and hydrogen of 95:5 (common grade) at 1030 oC and a soaking time of one hour. The results were examined by comparing the electric resistivity property, apparent density, bulk density as well as the porosity percentage inside the work piece material. The results revealed that the optimum combination of percentage Cu-C-Ni element was Cu92-C3-Ni5 (%wt), leading to the satisfactory Copper distribution in most of the structure. The size of sub sieve powder after grinding was found to be 22-31 micron with an electric resistivity of 1.45829E-05 k-ohm*cm. The minimum porosity percentage was found to be 2.19 %. Therefore, the element properties were found to be suitable for using as an electrode in EDM work when compared to that of the electrode prototype (EDM C3).

Quality assurance in the process of machining of parts made of heat-resistant alloys with the help of abrasive electrochemical grinding

For the purpose of efficient treatment of heat-resistant alloys, an abrasive electrochemical part grinding method is proposed using an advanced abrasive wheel cleaning method by means of abrasive wheel contamination assessment. The process was researched and it was revealed that a parameter which is a ratio of cutting force against the ECT (electrochemical treatment) phase duration within one round of spindle revolution is versatile, which means it does not dependent on the EDM electrode cutting feed rate, the depth of treatment, and is an independent value.