Precision microfinishing by electro-chemical honing

The International Journal of Advanced Manufacturing Technology, 2018

This work deals with the execution of micro-pockets on two different materials (AISI 316L stainless steel and ZrC+10MoSi2 UHT ceramic) using micro-EDM milling. The experiments were carried out by varying process parameters supposed to influence the surface quality, namely: discharge pulse on time, peak current, voltage and frequency. For both materials, tungsten carbide cylindrical electrodes were used. The investigation focused on the different results obtained in terms of surface roughness (Sa), kurtosis (Sku) and skewness (Ssk) to evaluate the different finishing level of the surface obtained as function of the process parameters. The aim of the present paper is to propose a method for studying the surface characteristics in terms of peaks and valleys shape and distribution with respect to the mean line according to ISO 25178. The results of this analysis can provide important information when designing micro-EDM milling processes.

American International Journal of Research in Science, Technology, Engineering & Mathematics, 2017

Electro chemical machining is a capricious/unconventional machining process which works on the guideline of electrolysis prepare. This sort of machining is exceptionally regular in aviation material and defense industry. But due to its effectiveness it is being connected to numerous other industry where the work piece is extremely hard to machine and when the geometry for machining is intricate. The objective of the paper is to state the current research and development in electro chemical machining processes. The advancements in tool design, plasma facing, pulse electro chemical machining, micro machining, electro chemical discharge machining, surface integrity and dimensional accuracy in electro chemical machining, electro chemical drilling, laser jet electro chemical machining, abrasive jet electro chemical machining, electrolyte jet electro chemical machining, high efficiency electro chemical machining, finite element analysis in electro chemical machining, optimization of surface roughness in electro chemical machining are evaluated. Keywords: electrolyte, electrochemical dissolution, plasma facing, surface integrity, micro machining, finite element analysis

Science & Technology Development Journal - Engineering and Technology

Based on the number of previous studies, this study aims to investigate the effects of process parameters of an Electrochemical Machining process, which are electrolyte concentration, the voltage applied to the machine, feed rate of the electrode, and Inter-Electrode Gap between tool and workpiece. Aluminum samples of 25 mm diameter x 25 mm height and 30mm diameter x 25mm height of the tool is made up of copper with a circular cross-section with 2 mm internal hole. The design of the system is based on the Taguchi method. Here, the signal-to-noise (S/N) model, the analysis of variance (ANOVA) and regression analyses are applied to determine optimal levels and to investigate the effects of these parameters on surface quality. Finally, the experiments that use the optimal levels of machining parameters are conducted to verify the effects of the process parameters on the surface quality of the products. The results pointed out a set of optimal parameters of the ECM process. The Inter-El...

Springer Proceedings in Materials, 2020

In this paper, the effect of processing parameters including feed rate (f), cutting depth (d), nose radius (r e), cutting speed (V) and also cooling condition such as dry condition, wet condition, and minimum quantity lubrication, on the surface quality of copper, as a low machinability material, was investigated. It was observed that the best surface quality and the lowest tool wear are achieved by minimum quantity lubrication, and the highest tool wear and the lowest surface quality are obtained under dry machining. However, there are no significant differences in surface quality and tool wear under dry machining when compared to minimum quantity lubrication and wet machining. Therefore, due to cost and environmental considerations, dry machining is recommended for turning commercially pure copper. According to the results, feed rate and nose radius are the most important factors affecting the surface roughness, respectively. At low feed rate, 1.2 mm nose radius is a good option to achieve the best surface roughness. Besides, at high feed rate, 0.8 mm nose radius is recommended. To achieve an acceptable surface roughness with suitable material removal rate, the combination of the lowest feed rate and the highest cutting speed, along with the moderate cutting depth and nose radius is suggested. The best surface roughness of 0.381 lm has been achieved at r e = 1.2 mm, V = 220 m/min, d = 0.5 mm, and f = 0.08 mm/rev, which is comparable with the surface quality obtained by the conventional grinding operation. The results also revealed that the existed empirical model can predict the surface roughness only at high feed rate and low cutting speed, and therefore, it cannot be recommended for predicting the surface finish of the materials with low machinability. Hence, a full quadratic model was developed for the prediction of the surface roughness, which can be used for the database of expert systems.

In today's manufacturing era, Electrochemical machining process provides good surface finish due to its controlled atomic dissolution of work material, involving chemical reactions during machining. To enhance the machining performance, precise selection of machining parameters, is still a demanding job in ECM process as it is very complex process involving so many unpredictable chemical reactions while machining. Due to chemical and electrical characteristics; effect on surface roughness of process also depends upon the type of material. A very rare work has been done by taking work material as input parameter for experimental study of ECM. The reaction of work material is investigated as an input parameter along with voltage and inter-electrode gap on improvement in surface roughness using orthogonal Array. Work-piece material is discovered as most significant factor influencing improvement in Surface Roughness followed by Inter-electrode gap and Voltage. Effect of ECM is found to be most prominent on Brass work-piece.

The major problem in the micro-manufacturing is concerned with achieving the good dimensional accurate products with the better surface finish, high MRR, no tool wear, absence of stress and no heat-affected zone. Micro-machining proved itself as a promising solution of this major problem. In recent days, industries are regularly looking for fabricating the micro-components which can be able to perform their complex functions in the sensitive areas of electronics, automotive, biomedical and optics. Now a day for miniature components micro-machining plays a very important role, its techniques are excellent to machine any complex shapes with good accuracy and bright surface finish. Material with any value of the hardness can be machined easily with all the offered advantages of micro-machining in the electrochemical micro-machining process (EMM). In this article; review of different methodologies and effect of machining parameters were studied along with different electrolytes; which plays a significant role in electro chemical micro-machining. The objective of this study is to know about the optimum micro-machining parameters for the EMM process and it is also much important to find out the research gap through the different studies. In this study, it has been found out MRR and overcut are depends upon the voltage, electrolyte concentration, IEG, pulse ON/OFF time, pulse duration, pulse frequency, RPM of the tool and flow rate of electrolyte. The proper selections of parameters in EMM are essentials for achieving the overall improvement in the micro-machining operation.

In the paper experiments of the electrochemical smoothing process has been presented. The smoothing has been carried out on the whole surface after rough milling. This way of smoothing, in comparison to smoothing with universal electrodes, gives possibility of decreasing time of machining. However, as it had been proved in the paper, the final results of machining are limited by shape errors created in electrochemical process.

2021

Micromachining is the most suitable technology for the production of very small components (micro-components) in the industry. It is a high-precision manufacturing process with applications in various industrial sectors, including machine building. This chapter presents the experimental study of the roughness (Ra and Rt) of aluminum alloys using a specific micro-turning process. The roughness measurements carried out show how it is possible to achieve very good surface qualities up to 0.05 mm diameter. For lower diameters, the surface quality worsens and the shape defects increase (conicity) due to the very low rigidity of the workpiece, which makes it very sensitive when passing through the forming process. The fundamental objective of this research is to analyze the surface quality of the finishes obtained in these micromachining processes and to evaluate their suitability to the specifications required by the mechanical industry (roughness, presence of burrs, shape and geometry, etc.). Predictive roughness models are proposed, with a good degree of approximation, to help characterize micromachining processes.

Processes, 2022

An electrochemical machining (ECM) process for microcavity fabrication with deionized water (DI-water) and an ECM polishing hybrid with alumina powder of 1.0 μm grains on a single micro-EDM machine are proposed. The process adopts tungsten carbide as tool electrode and M-333 tool steel as the mold material. It reveals that employing the 30 μm/min feed rate with 50 mA and 0.2 ms of pulse-width is suitable for DI-water electrochemical machining. The DI-water ECM process can achieve an excellent surface roughness at Ra 0.169 µm on a semispherical round cavity. Combining the ECM with hybrid polishing with the alumina powder can achieve a better profile for a much deeper cavity than pure electrolytic discharge machining. The hybrid ECM polishing can efficiently finish a micro square insert of 0.6 mm length at 64 μm depth. Such ECM milling can achieve an S-shaped microchannel of radius 1.0 mm and a slot of 1.0 × 0.5 mm2 with 110 μm depth, demonstrating its feasibility and the surface inte...

Lecture Notes in Mechanical Engineering, 2021

Robotics and Computer-Integrated …, 2002

A better understanding of high rate anodic dissolution processes is urgently required for electrochemical micromachining (EMM) to become a widely employed manufacturing process in the electronic and precision manufacturing industries particularly in the micromanufacturing domain. A successful attempt has been made to develop an EMM setup for carrying out in depth independent research for achieving satisfactory control of electrochemical machining process parameters to meet the micromachining requirements. The developed EMM setup mainly consists of various sub-components and systems, e.g., mechanical machining unit, microtooling system, electrical power and controlling system and controlled electrolyte flow system, etc. All these system components are integrated in such a way that the developed EMM system setup will be capable of performing basic and fundamental research in the area of EMM fulfilling the requirements of micromachining objectives. r

Procedia CIRP, 2016

Micro machining of nonconductive materials such as glass is critical as it has numerous applications in microsystems including biomedical devices, micro-reactors, micro-pumps, micro-accelerometers and MEMS. Electrochemical discharge machining (ECDM) is a promising process for the micromachining of glass. However, ECDM often inadvertently causes surface wrinkling and surface damages. This paper studies the effect of concentration of electrolyte in ECDM on the integrity of a micro machined hole surface. The study includes: analysis of surface roughness and micro-defects, microstructure by EDAX testing and hardness testing by nano indentation. It was found that lower electrolyte concentrations in ECDM enhance chemical etching that causes surface wrinkling.

International journal of applied research, 2022

Machining of deep holes with a special configuration in parts subjected to intensive wear is realized mainly by electrochemical methods. The operational, technological and economic parameters of the parts are increased after wear-resistant coatings are deposition them. Electrochemical coatings on parts of aluminum alloys are formed by anodizing, and on steel parts by chrome plating. The presence of coating leads to an increase in the technical resource, reliability parameters-faultlessness, durability, repairability and keeping, corrosion resistance, as well as the main indicators hardness, wear resistance, heat resistance and thermal conductivity. Anodized and chromed coatings are characterized by low levels of residual stresses, high adhesion to the base material and a low coefficient of friction. The relevance of the issues discussed in the article is determined by the need to create new or more efficient technologies for manufacturing of details with higher durability and wear resistance, operating in conditions of extreme, intensive, cyclic thermodynamic loading. The competitive environment, combined with the exceptional dynamics of the market for products, which include parts with a similar configuration and purpose worldwide, require the improvement of mechanical, thermal, dynamic and tribological indicators to be realized in conditions of constantly increasing productivity and decreasing technological cost while complying with the requirements for preservation, and in a number of cases for improving the geometrical and physico-mechanical qualities of the treated surfaces.

2021

Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2013

Milling is one of the most important processes to manufacture dies and moulds. However, it cannot machine regions with small sizes and difficult access to the cutting tool. Such regions must be machined by electrodischarge machining (EDM). It is known that EDM can damage the integrity of the machined surface, and also requires long processing time, due to both, the necessity to manufacture the electrode and its low material removal rate. The micromilling process, using high-frequency spindle together with cutting tools smaller than 1 mm of diameter has been emerging as an option for machining small regions in dies and moulds. In this context, this paper aims to help the understanding of the cutting phenomenon to manufacture small areas using both machining techniques, in order to identify the adequacy to replace EDM for micromilling in such circumstances. Machining experiments were carried out on AISI P20 (29HRC) and AISI H13 (45HRC) steels. These materials are commonly used in the mould and die industry. Residual stress on machined surface, surface finishing (2D and 3D), SEM images, microstructure and microhardness were accessed. The residual stress was tensile for the EDM pieces and compressive for the milled parts. The material had more influence on the residual stresses values than the process and H13 had higher values than P20. The surface roughness from the EDM machining pieces was not influenced by the material. The EDM caused white layer and microcracks on both materials, but much more intensely on H13. These occurrences were not found on the milled workpieces. Plastic deformation occurred on the micromilled surfaces, but without phase transformation of the material's microstructure. Unexpectedly, the roughness on the hardest material (H13) was worse than P20 for the milling experiments. It was attributed to more intense tool deflection when milling H13. In general, roughness obtained in micromilling was about six times lower than that obtained using EDM and it presented a regular surface topography, unlike the EDM specimens.