Search

The synthesis of a co-precipitated mixture of tantalum and brass nanoparticles (Ta and Cu/Zn) using a micro-wire-electro-discharge-grinding (µ-WEDG) with a combination of multiple process parameters is explained in this article. Tantalum and brass nanoparticles are produced in a dielectric medium Diel-7500 EDM oil. µ-WEDG represents a cutting-edge mechanical micro-machining technique extensively employed for machining micro rods. This method uses a grinding process that expels debris via melting and evaporation. This process disperses a fraction of nanometre-sized debris within the dielectric medium. Traditionally, this debris consisting of nanoparticles has been classified as unwanted substances and subsequently eliminated from the system. However, it now requires a thorough reassessment for possible usage. Hence, the characterization of tantalum and brass nanoparticles is conducted through Field emission Scanning Electron Microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses. The process parameters are capacitance, voltage and spindle speed. The investigation reveals that the mean nanoparticle size of produced tantalum nanoparticles range from 25 to 200 nm, while brass nanoparticles range from 300 to 950 nm. Furthermore, a notable correlation is observed between decreasing capacitance and the corresponding reduction in the shape and size of nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract The synthesis of a co-precipitated mixture of tantalum and brass nanoparticles (Ta and Cu/Zn) using a micro-wire-electro-discharge-grinding (µ-WEDG) with a combination of multiple process parameters is explained in this article. Tantalum and brass nanoparticles are produced in a dielectric medium Diel-7500 EDM oil. µ-WEDG represents a cutting-edge mechanical micro-machining technique extensively employed for machining micro rods. This method uses a grinding process that expels debris via melting and evaporation. This process disperses a fraction of nanometre-sized debris within the dielectric medium. Traditionally, this debris consisting of nanoparticles has been classified as unwanted substances and subsequently eliminated from the system. However, it now requires a thorough reassessment for possible usage. Hence, the characterization of tantalum and brass nanoparticles is conducted through Field emission Scanning Electron Microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses. The process parameters are capacitance, voltage and spindle speed. The investigation reveals that the mean nanoparticle size of produced tantalum nanoparticles range from 25 to 200 nm, while brass nanoparticles range from 300 to 950 nm. Furthermore, a notable correlation is observed between decreasing capacitance and the corresponding reduction in the shape and size of nanoparticles.

Micro-tools comprising difficult-to-machine materials have seen widespread application in micro-manufacturing to satisfy the demands of micro-part processing and micro-device development. Taking micro-shafts as an example, the related developmental technology, based on wire electric discharge grinding (WEDG) as the core method, is one of the key technologies used to prepare high-precision micro-shafts. To enable efficient and high-precision machining of micro-shafts with target diameters, instead of performing multiple repeated on-machine measurements and reprocessing, a geometric constraint strategy is proposed based on the previously introduced twin-mirroring-wire tangential feed electrical discharge grinding (TMTF-WEDG). This strategy encompasses the tool setting method, tangential feed distance compensation, and an equation that establishes the relationship between tangential distance and diameter variation. These components are derived from a key points analysis of the geometric constraints. The micro-shafts with diameters of 50 µm and consistencies of ±1.5 µm are repeatedly processed. A series of micro-shafts with diameters ranging from 30 µm to 120 µm achieve geometric constraints with a diameter accuracy of ±2 µm, accompanied by the complete continuous automation of the entire process. Accordingly, it can be concluded that the geometric constraint strategy is flexible and stable and can be controlled with high precision in the TMTF-WEDG process. [ABSTRACT FROM AUTHOR]

The recast layers, discharge craters and micro-cracks on the micro-shaft surface fabricated by wire electrical discharge grinding (WEDG) can negatively affect mechanical properties and fatigue life in particular as micro tools. An online polishing method using fluid magnetic abrasives (FMA) is proposed to improve the micro-shaft surface quality. A polishing device is designed that uses two permanent magnets to apply an external magnetic field and changes FMA container thickness to adjust magnetic field strength in the processing area. The FMA polishing device is integrated into a micro-EDM machine tool with a WEDG function, and the micro-shaft can be polished online by moving the set trajectory in the FMA. A single-factor experiment was employed on tungsten material micro-shafts fabricated by WEDG to explore the polishing ability. The effects of micro-shaft diameter, magnetic field strength, polishing time, spindle speed, abrasive particle size, and motion trajectory were analyzed. After FMA polishing, the surface roughness Ra could be reduced from 0.1 μm to below 0.05 μm generally, and the minimum could be reduced to 0.019 μm. Results show that the surface material removal was uniform and obvious. The tungsten micro-shafts had almost no deformation compared to before polishing, while the brass micro-shafts deformated obviously. After FMA polishing, the recast layer was significantly removed and the micro-shaft surface quality was improved, which was discovered by observing the surface topography. It proves that the online polishing of micro-shafts by FMA is feasible and valuable. [ABSTRACT FROM AUTHOR]

Micro-tools comprising difficult-to-machine materials have seen widespread application in micro-manufacturing to satisfy the demands of micro-part processing and micro-device development. Taking micro-shafts as an example, the related developmental technology, based on wire electric discharge grinding (WEDG) as the core method, is one of the key technologies used to prepare high-precision micro-shafts. To enable efficient and high-precision machining of micro-shafts with target diameters, instead of performing multiple repeated on-machine measurements and reprocessing, a geometric constraint strategy is proposed based on the previously introduced twin-mirroring-wire tangential feed electrical discharge grinding (TMTF-WEDG). This strategy encompasses the tool setting method, tangential feed distance compensation, and an equation that establishes the relationship between tangential distance and diameter variation. These components are derived from a key points analysis of the geometric constraints. The micro-shafts with diameters of 50 µm and consistencies of ±1.5 µm are repeatedly processed. A series of micro-shafts with diameters ranging from 30 µm to 120 µm achieve geometric constraints with a diameter accuracy of ±2 µm, accompanied by the complete continuous automation of the entire process. Accordingly, it can be concluded that the geometric constraint strategy is flexible and stable and can be controlled with high precision in the TMTF-WEDG process.

In order to meet the processing requirements of precise cylindrical parts on hard and difficult-to-machine materials, this paper introduces wire electrical discharge grinding (WEDG) using thin plate wire guide for cylindrical parts machining. The spindle system and the wire transport system to realize this processing method was added to a low speed wire electrical discharge machining (LS-WEDM) machine tool. In order to realize the online measurement of the machining accuracy of the cylindrical parts, an online measurement system of two-degree-of-freedom based on laser displacement sensor was built. The reasons for the incomplete removal of the machined surface were analyzed. Through the application of a new tool setting strategy and reasonable selection of processing parameters, the phenomenon of incomplete processing can be avoided. The experimental research on the effects of part rotational speed, wire feed rate, wire running speed and wire tension on roundness, surface roughness Sa, and surface morphology were carried out. Finally, example of the cylindrical parts is given to verify the machining accuracy. [ABSTRACT FROM AUTHOR]

This paper discusses the development of a numerical model and its comparison with the analytical model to predict the wire deflection in WEDG. The movement of wire between upper and lower guides creates vibration during the machining process which can create micro deflection of the wire. The Finite Element Analysis model [FEA] for the wire deflection is analyzed and compared with the analytical model. The deflection of the wire due to the input current may affect the machining of micro parts, which will be used for further research in micro machining and also will help us to choose the parameters such as current, spark gap, wire feed, and the speed of the workpiece during micro machining with WEDG. The FEA results for various forces were compared with the analytical results and found that the developed numerical model results are in good agreement.

In micro electrical discharge machining (micro-EDM), the precision fabrication of cylindrical micro rods is difficult to achieve with a high processing efficiency. In order to overcome this challenge, this paper proposes a new processing method, which is denoted as twin-mirroring-wire tangential feed micro electrical discharge grinding (TMTF-WEDG). The machining principle, characteristics, and realization of the new method are firstly introduced. Then, the advantages of TMTF-WEDG in terms of machining efficiency and accuracy are demonstrated. The experimental results have shown that the machining efficiency can be increased to more than 70% in comparison with conventional tangential-feed wire electrical discharge grinding. It has also been proved that a minimum removal of material corresponding to a reduction of less than 1 μm in the diameter of a micro rod can be obtained by TMTF-WEDG. This considerably helps in improving the accuracy and repeatability of the machining process. A deviation of less than 1 μm on the diameter of a micro rod has been obtained in a length range of 800 μm. The process repeatability in machining five micro rods has been established to be below 2 μm. The proposed method is therefore of great significance for improving the machining efficiency and ensuring a high precision in the shaping process of cylindrical micro rods. • TMTF-WEDG method was proposed to improve the machining efficiency and accuracy of micro rods. • An analysis of diameter variation and remove layer thickness characteristics of the micro rods were illustrated. • Compared to TF-WEDG, the TMTF-WEDG can improve processing efficiency by 1.7 times. • A minimum removal layer thickness of less than 1μm was obtained in the experiments. • The uniformity of a single micro rod is <1 μm in the length range of 800 μm, and the repeatablity of micro fods is < 2 μm. [ABSTRACT FROM AUTHOR]

Micro-forming tool is very important for micro-hole drilling. Electrical discharge machining (EDM) is used in micro-fabrication because of low reaction force. Moreover, micro-electrode is an important micro-tool. In this study, this paper proposes a micro-pin-forming method in which a rotating cylindrical electrode approaches a forming plate. As the processing area in this method is larger than those other methods, a higher removal rate is achieved compared to other methods. Moreover, a high aspect ratio of the micro-pin is achieved. A rotating WC-Co rod of 0.5 mm diameter is moved through the plate that is a zinc alloy plate of 2 mm width and 5 mm thickness. The result showed thad a micro-pin electrode of 90 μm diameter and 5 mm length can be gotten reproducibly. However, a micro-pin forming smaller than 10 μm in diameter is difficult to obtain using the machine tools currently available in the market. Miniaturization limits through micro-pin forming by the EDM are determined based on the discharge conditions, grain size of pin material, thermal residual stress, and lateral vibration of the micro-pin caused by the rotation of the micro-pin. In this study, it is considered that micro-pin vibration caused by its rotation, which affects the miniaturization limits. The rotational speed of the micro-pin is an important factor for high aspect ratio of the micro-pin forming. Finally, the forming of a micro-pin of 8 μm diameter and 250 μm length is performed considering the rotation of the micro-pin. [ABSTRACT FROM AUTHOR]

Polycrystalline diamond (PCD) micro-grinding tools are shaped by using different electro-discharge machining processes, among which wire electro-discharge grinding (WEDG) process is widely accepted due to its capability of producing highly precise, ultra-thin and dimensionally accurate tools. Observing the effects of different WEDG conditions on the tool surface and analyzing the tool's topographic features relevant to micro-grinding are of utmost importance. Current study deals with dressing of polycrystalline diamond tool blanks at different combinations of wire tension and discharge energy to observe the effects of dressing parameters on the tool surface morphology and statistics. Surface roughness, ridge type surface defects and diametrical error in the fabricated tool are analyzed with respect to discharge energy and wire tension. High wire tension produces tools with consistence surfaces and desired diameter. Binder material cobalt is efficiently melted and flushed out from the tool surface at high wire tension, which leads to proper segregation and protrusion of diamond abrasives from the surface. Static abrasive grit density measured by processing the 3D surface data of the tool is found to be ≈165–170 per mm, as compared to theoretically determined value of ≈200 per mm. Micro-slot grinding experiments are carried out on BK7 glass, to quantify the effects of the dressing parameters on the micro-grinding performances of the PCD micro-tools. Cutting forces for all the tools are found to be within 1 N whereas normal force exceeds beyond 1 N. Cutting forces are found to be higher for the tools dressed at high wire tension due to large diameter of the tool as compared to that of undersized tool obtained at low wire tension. Cutting nature is found to be mix of ductile-brittle for the machining conditions adopted in this paper. Unlabelled Image • PCD micro-tool is dressed in rough cut and finish cut steps using WEDG. • Wire tension and discharge energy have significant effects on PCD tool surface. • Roughness, defects and diametrical error in tool are reduced at high wire tension. • Static cutting edge density is measured as 165–170 per mm. • Tool dressed at high wire tension produces slots with minimum surface roughness. [ABSTRACT FROM AUTHOR]

Manufacture of micro cylindrical electrodes has been proposed using the CNC wire electric discharge machine by attaching a rotary spindle. The work material tungsten is chosen due to its wide spread uses in aerospace, electronics and health care areas. In this work, tungsten work-piece of Ø2.0 mm is machined to Ø0.4 mm by WEDG by considering the factors such as spindle speed, peak current, pulse off time and wire speed. The full factorial experimental design has been used to find out the effect of process parameters. The results are further analyzed through analysis of variance (ANOVA) and surface plots for confirmation. It was found that spindle speed, pulse off time and wire speed has higher influence on material removal rate from this study. At low pulse off time and low wire speed more thermal energy is transferred to the work-piece which results in higher material removal of the material. The optimal process parameters for higher MRR are peak current of 5 A, pulse off time 1 µs, wire speed of 5 m/min and spindle speed of 700 rpm. The SEM images of machined work-pieces confirm the results obtained. The confirmation tests have been done and found that the variation is within 1.5%. From the study electrodes of Ø400 µm has been machined to a length of 10 mm (aspect ratio l/d of 25) which is otherwise a challenge by the conventional machining processes. [ABSTRACT FROM AUTHOR]

This study aims at developing a machine center consisting of high-speed micro-milling machine, micro-EDM and coordinate measuring machine. The machine center uses a commercially available PC-Based CNC controller and micro-EDM power supply. The structure design is based on an open L-shaped granite base, where a Z-axis platform is mounted on the top of an L-type base, while X and Y-axis platforms are assembled by stacking. Additionally, a fuel tank, WEDG winding mechanism and a work piece holder were fixed to the X-axis work platform. Three-axis positioning stages use servomotors to drive lead screws for motion control. Equipped with a commercially available PC-Based CNC controller, any processing path and precision motion control can be achieved. In addition, the Z-axis platform includes a commercially available rapid adapter for the rapid assembly of C-axis rotation, high-speed micro-milling spindle and three-dimensional measuring probe. This means that the machine can quickly switch between micro-EDM, high-speed micro-milling and three-dimensional measurement. The machine center successfully produced micro probes with a front-end sphere with a diameter of less than 100 μm. Combined with a self-developed trigger circuit, it also completed a three-dimensional touch trigger probe. The measurement software was developed with Borland C++ Builder. Integrating the three-dimensional touch trigger probe with the three-axis linear scale, the three-dimensional coordinates of the measured values were calculated and processed. It has been successfully applied to the measurement of point, line, circle and angle.

In microelectrical discharge machining (μEDM), the machining repeatability of microshafts with the same diameter is low due to the complex and stochastic nature of sparking. To improve machining repeatability, the effects of the main error sources on diameter accuracy of microshafts fabricated by wire electrical discharge grinding (WEDG) were analyzed. Strategies to minimize diameter differences between the target microshaft and the microshaft finally obtained by semifinishing and finishing were then proposed. Determining an appropriate infeed (depth of a cut) according to the desired erosion depth in the radial direction (Δ R) of microshafts was chosen as the control strategy for the semifinishing of microshafts produced by WEDG. To determine the infeed, empirical models that evaluate the relationship between the infeed and Δ R were developed through a large number of experiments. For the finishing of microshafts using WEDG, machining strategies such as zero infeed and stopping the wire electrode running, were proposed to eliminate some of the inherent errors. Finally, the empirical models developed for determining the infeed were verified by the successful fabrication of a stepped microshaft, which has small deviations from its desired diameters. By employing the developed empirical models and machining strategies, diameters of 26 out of 28 microshafts fabricated were found to lie in the range of 45 ± 2 μm. The experimental results verify that the diameter control strategies are effective and can be used to improve machining repeatability. [ABSTRACT FROM AUTHOR]

This paper describes a hybrid gluing and assembling process on micro electrical discharge machine (EDM) to produce micro ball-ended spherical stylus tips for micro coordinate measurement machine's (CMM's) tactile probing heads. Combining wire electro-discharge grinding technology and position controlling function of EDM, a micro glass ball could be glued onto the cantilever successfully. The experimental results show that the roundness of the largest profile micro glass-ball-ended styli with a 0.07-mm diameter could be as small as 0.613 μm. The deviation and roundness of the stylus tips can be controlled more effectively by this gluing and assembling process. The adhesion strength of the gluing stylus tip is approximately 12 mN. These ball-ended stylus tips could be used on micro CMM's tactile probing head for micro component metrology in the near future. [ABSTRACT FROM AUTHOR]

This paper investigates the technological capabilities of a hybrid micro machining process for performing wire electro-discharge grinding (WEDG). In particular, micro wire electrical discharge machining (μWEDM) is employed in combination with a rotating submergible spindle to perform WEDG. In this research, first a machining strategy for workpiece preparation is presented. Then, the effects of different machining setup parameters on the achievable surface finish after WEDG are investigated. In particular, an experimental study was conducted to identify the most statistically significant setup parameters for performing the main cut that affect the resulting surface quality. A signal-to-noise (S/N) ratio analysis was conducted to optimise the technological parameters for performing WEDG. By modifying the discharge energy for main cuts when performing WEDG surface finish comparable to that of μWEDM can be achieved. In addition, a simple and cost-effective method for on-the-machine estimation of resulting surface roughness is proposed. Especially, by applying inductive learning a surface roughness prediction model for WEDG can be generate based on data acquired by monitoring on-line the process. [ABSTRACT FROM AUTHOR]

This study describes the use of micro electro-discharge machining (µ-EDM) scanning technology to fabricate micro three-dimensional cavities and microtools fabrication on polycrystalline diamonds (PCD). The experimental results show that short-pulse discharge from an resistor-capacitor (RC) circuit is more effective and precise than a transistor (Tr) pulse generator while machining PCDs by µ-EDM. The surface roughness of PCD using the µ-EDM scanning process could be as small as Ra 0.2 µm, even when the diamond grain size is considerably larger. Moreover, small PCD tools for cutting brittle materials could be easily fabricated by the same µ-EDM process. Thanks to their hardness and excellent thermal conductivity, PCDs could be utilized in the near future, not only for micro molds, but also for tools to cut brittle material. [ABSTRACT FROM PUBLISHER]

This article describes a new hybrid machining process with combination twin-wire electrodischarge grinding (twin-WEDG) and two electrodischarge circuits to produce microelectrode tools rapidly. The results show that transistor and RC electrodischarge circuits could be jointly integrated into micro-EDM to shape microelectrode tools. Compared to conventional single WEDG technology, the twin-WEDG system utilizing both rough and finished machining combined into only one process can reduce machining time by two-thirds and achieve high efficiency when producing microtools. This high-speed microtool fabrication process can be applied not only to micro-electrode machining, but also to micropunching tool and microprobing tips machining. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, vibration-EDM technology was introduced by the vibrating worktable designed to fabricate noncircular micro-electrodes and micro die-openings using wire electro-discharge grinding (WEDG). Micro punches and micro die-openings with different clearances were fabricated by controlling the spark gap in micro electrical discharge machining (micro-EDM). The micro-punching experiments include producing triangular and hexagonal micro-holes with a side length of 200μm on brass strip. Punching of successive hexagonal micro-holes was also carried out successfully. The micro-forming experiments were conducted on copper and brass, producing cup-shaped protrusions with a diameter of 300μm. All the experimental results show that the modified micro-punching machine is able to perform both micro-punching and micro-forming operations. [Copyright &y& Elsevier]

Abstract: The purpose of this study is to study burr formation in micro-machining using micro-tools. The micro-tools employed are fabricated by micro-EDM using the wire electro-discharge grinding (WEDG) method in the micro-EDM/milling machine we had already developed. Micro tungsten-carbide tool with a minimum of 31-μm in diameter had been fabricated. The simple-shaped micro-tool fabricated is able to perform the micro-machining operation which is a combination of micro-milling and grinding processes. Micro-slot and micro thin-walled structure had been produced on Al 6061-T6 materials successfully. Burr formation in micro-machining is investigated experimentally and classified into four types: primary burr, needle-like burr, feathery burr and minor burr. Formation mechanisms of these burrs and the relationship between their existence and the machining condition are discussed. [Copyright &y& Elsevier]

Abstract: In this research vibration-EDM is realized by the vibrating worktable designed, which is employed in the micro-punching machine we had already developed. It is found that larger feed and better surface finish can be achieved in micro-EDM with vibration machining. Circular and noncircular micro-electrodes of diameter below 200μm were fabricated with vibration-EDM and the setup of u-axis. Experiments to punch micro-holes of diameter 200μm on SUS304 stainless steel and brass strips were carried out. Mass punching of micro-holes on brass strip was performed successfully, using the automatic feeding system developed. The capability of micro-punching and effects of parameters on the quality of punched micro-hole are studied. [Copyright &y& Elsevier]

Abstract: This paper describes the development of a novel micro-punching machine that is capable of producing precision micro-holes. A significant feature of this machine is to fabricate the micro-punch and then the micro-die in the same machine, totally eliminating the eccentricity between the punch and the die when punching is proceeded. By applying vibration machining technique, we can decrease the possibility of electric short-circuiting during the micro-EDM process. The utilization of a proportional solenoid as the power unit of the micro-punching machine and as the source of vibration is found to be a successful attempt. Experiments to punch micro-holes with diameters of 0.1 and 0.2mm on an SUS 304 stainless steel strip with 0.1mm in thickness were carried out. The results show that the performance of this machine and the geometry of punched micro-holes are satisfactory. [Copyright &y& Elsevier]

Abstract: This research presents a novel process using micro electro-discharge machining (micro-EDM) combined with high-frequency dither grinding (HFDG) to improve the surface roughness of micro-holes. Micro-EDM is a well-established machining option for manufacturing geometrically complex small parts (diameter under 100μm) of hard or super-tough materials. However, micro-EDM causes the recast layer formed on the machined surface to become covered with discharge craters and micro-cracks, resulting in poor surface quality. This affects the diameter of the micro-hole machined and undermines seriously the precision of the geometric shape. The proposed method that combines micro-EDM process with HFDG is applied to machining high-nickel alloy. As observed in SEM photographs and surface roughness measurement, HFDG method can reduce surface roughness from 2.12 to 0.85μm Rmax with micro-cracks eliminated. Our results demonstrated that micro-holes fabricated by micro-EDM at peak current 500mA followed by HFDG at 40V can achieve precise shape and good surface quality after 6–8min of lapping. [Copyright &y& Elsevier]

The electrical discharge machining of cylindrical components is decisively influenced by the process conditions resulting from the rotational movement of at least one of the two electrodes. This paper analyses the machining effects developing at high peripheral speeds. Focus of investigation is especially placed on the evaluation of the effects on process behaviour and surface topography. The process variants electrical discharge turning (EDT), electrical discharge grinding (EDG), and wire electrical discharge grinding (WEDG) are compared with respect to the influence by the above-mentioned effects and the resulting process planning. [Copyright &y& Elsevier]

This paper describes a new hybrid technique combining wire electro-discharge grinding (WEDG) technology with one-pulse electro-discharge (OPED), to fabricate multi-micro-spherical probes. The results show that a burnished micro-spherical probe with diameter of about 40 μm could be formed instantaneously, which is not available with conventional machining methods. The unevenness of the radius is about 3 μm with repeatedly machining at the same conditions and the center shifting tolerances of the sphere is about 1 μm. Compared with micro-discharge electro-machining (EDM), the surface roughness of the probe is much smaller than discharge crater. [Copyright &y& Elsevier]

With the development of the WEDG (wire-electrodischarge-grinding) it became possible to produce very small electrodes or products like e.g. ejection pins or cores for mould inserts. A new field for the WEDG is the production of milling tools for micro-cutting. The Institute of Production Science (wbk) of the University of Karlsruhe and the Institute of Industrial Science of the University of Tokyo, Center for International Research on MicroMechatronics, developed together a way to produce these milling tools in tungsten carbide with CNC-controlled EDM machines. This research has shown the potential of the machining of micro-cutting tools with a diameter smaller then 100 μm—which is at the moment the size of the smallest commercial milling tool in tungsten carbide—by micro-EDM. [Copyright &y& Elsevier]

With this method a rod electrode with negative polarity is rotated and fed into a plate electrode to form holes. After the rod electrode returns to the initial position, the axis of the rod electrode is off-centered from the center of the hole at a certain distance. The polarity of the rod electrode is then reversed, and the rod electrode is fed into the plate electrode, either with or without rotation. Since holes are formed by the rod electrode itself, the rod electrode can be machined very precisely. Since this method does not need initial positioning of the tool electrode with respect to the plate electrode, the operation is easy and short. [Copyright &y& Elsevier]

The paper describes a device using a copper stripe for EDM manufacturing. This new approach is trying to get better results in productivity of material removal. The paper describes the construction of the device problems accompanied with it's use and shows results reached with this approach. The paper also shows some new possibilities in further development of stripe EDM. [ABSTRACT FROM AUTHOR]

• Key technologies were proposed to improve the diameter uniformity and repeatability of micro-shafts fabricated by TMTF-WEDG. • The critical factors of TMTF-WEDG system were analyzed, which affects the the diameter uniformity and repeatability of micro-shafts. • New strategies were proposed for improving the performance of TMTF-WEDG. • A micro-shaft with a diameter of 45μm and uniformity of ± 0.5μm was successfully fabricated. • For five repeated fabricated micro-shafts, the diameter repeatability was controlled within ±1 μm. The new method of micro-shaft fabrication, named twin-mirroring-wire tangential feed electrical discharge grinding (TMTF-WEDG), is mainly characterized by the tangential feed strategy and the narrow slit formed by twin-mirroring-wire to achieve the diameter control of micro-shaft. The critical factors of micro-shafts accuracy and repeatability include processing position offset of micro-shaft, front edge position fluctuation of wire electrodes, and asymmetry of the twin-mirroring-wire electrodes, which cause the deviation of the tangential feed path and fluctuation in narrow slit width. The diameter of the micro-shaft was smaller than the theoretical value with processing position offset, which is not conducive to the control of the micro-shaft diameter. The front edge fluctuation of the wire electrodes caused the variation of the micro-shaft diameter to be around ±3 μm in the axial direction. The asymmetry of the twin-mirroring-wire electrode is the key factor affecting the tangential feed path which further affects the controlling the repeatability of the micro-shafts. New strategies were proposed, including the determination of the initial machining position achieved by tool setting, improvement of the twin-mirroring-wire system, the determination of the feed path, and improvement of feed strategy for trimming the taper of micro-shafts. The processing results show that a micro-shaft with a diameter of 45 μm and uniformity of ± 0.5 μm was successfully fabricated. For five repeated fabricated micro-shafts, the diameter repeatability was controlled within ±1 μm. [ABSTRACT FROM AUTHOR]