Modeling and Influence of Voltage and Duty Ratio on Wire Feed in WECM: Possible Alternative of WEDM

The production of economical turbine slots with high efficiency and good surface integrity is a common concern in aviation manufacturing. State-of-the-art wire electrochemical machining (WECM) cannot afford the efficient precision machining of macro structures with thicknesses over tens of millimeters. This work investigated a pulse-current WECM process combining high-speed rotation of a helical wire tool and axial electrolyte flushing. Theoretical analysis and experimental results indicate that pulse frequency has a significant influence on the machining of thick specimens. The pulse-current charging process was prolonged with the increase in workpiece thickness, and it took up the majority of the pulse-on time at a pulse frequency over 50 kHz when the workpiece thickness reached 15 mm. The maximum feed rate first increased with pulse frequency, and then decreased from 20 to 100 kHz when a 20-mm-thick workpiece was being cut. Subsequently, the processes of electrolyte refreshment and product removal were maximized when the helical wire electrode rotated clockwise, and axial electrolyte flushing was applied. Finally, a fir-tree slot of 20 mm thickness with good dimensional consistency and good surface quality was stably processed at a rate of 5 μm s −1 .

mentioning

confidence: 99%

Pulse-Current Wire Electrochemical Machining with Axial Electrolyte Flushing along a Rotating Helical Wire Tool

Fang¹,

Han²,

Mi³

et al. 2020

“…In contrast to the thermal induced material removal processes, ECM can machine features without generating thermal stress which can deteriorate surface quality and integrity, without the formation of a heat affected zone (HAZ) where surface property changes due to the modification of the grain structure, without formation of burrs which are detrimental to product homogeneity, and without wearing out of the tool leading to its premature failure. [4][5][6] However, recent technological advances in the areas of precision and sophistication, along with the requirement for downsized metallic components, necessitated the implementation of the anodic dissolution process at the micrometer level, i.e in the range of 1-999 microns. This process, widely termed as electrochemical micromachining (EMM), 7 z E-mail: subhrajit.me32@gmail.com; bdoloionline@rediffmail.com; bb13@rediffmail.com has the capability to fabricate features within micrometer ranges by ensuring better accuracy and precision in the order of ±1μm on 50μm.…”

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confidence: 99%

Review—Wire Electrochemical Machining Process: Overview and Recent Advances

Debnath

Doloi

Bhattacharyya

2019

Self Cite

Wire electrochemical machining (WECM) is a recently introduced fabrication process which is yet to be fully investigated. Preliminary studies have shown that it offers superior feasibility and capability concerning the fabrication of various microfeatures. More extensive investigations are needed to discover any associated problems with the process and to extend its applicability and efficiency by determining its limitations in order to make this process a successful fabrication technique not only in microdomains but also for macro fabrications as well. Here we begin with a detailed overview of the fundamental and technological aspects of the WECM process. We then discuss its mass transfer strategies and kinematics, which are equally important as associated operating parameters, as well as the apparatus, materials, and machining conditions, challenges, and applications. Finally, we note recent advances to guide upcoming research attempts and future investigations aimed at making this anodic dissolution process proficient and established.

“…It is convenient to fabricate complex microstructures through the numerical controlled relative movement between the wire and the workpiece. 5,6 An ultrashort pulsing voltage causes localized anodic dissolution and can produce precise sub-micrometer localized machining. In WECMM, bubbles and by-products such as metal hydroxide particles generated in the machining gap, greatly influence electrolyte conductivity and thereby affect the material removal rate.…”

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confidence: 99%

Helical Carbon Nanotube Fiber Tool Cathode for Wire Electrochemical Micromachining

Meng

Zeng

Zhu

2018

Helical carbon nanotube fibers (CNFs), proposed as lightweight, high-strength, electrically conducting cables, have potential as tool cathodes in wire electrochemical micromachining (WECMM). WECMM has increasingly become recognized as a versatile technique for producing planar contour micro-features, and holds great advantages for micro-shaping of difficult-to-machine materials. However, the processing performance is affected by the mass transport rate in the narrow inter-electrode gap. Therefore, a helical CNF with superior hydrophilicity and high tensile strength is proposed as a new tool cathode for WECMM. Moreover, the electroplating technique is proposed as a means to improve the electrical conductivity of the CNF electrode. The synthesis of a Cu-CNF electrode had a two orders of magnitude enhanced electrical conductivity of about 2.0 × 10 7 S/m and a tensile strength of about 1350 MPa. An overall improvement of processing performance for WECMM was achieved. The machining accuracy in terms of slit width and its standard deviation were 38.8 μm and 0.2 μm, respectively. The surface average roughness of side wall was 0.022 μm. Finally, the five-layered micro tenon structures on Ni-based metallic glass were fabricated successfully by using three helical CNF electrodes simultaneously. The total machining efficiency in terms of feed rate attained 9.0 μm/s.