High-precision spindle head with combined function of rotation and inchworm feed for micro-EDM with WEDG

doi:10.1007/s40436-025-00556-x

Abstract

Abstract: The combination of wire electro-discharge grinding (WEDG) and a rotary spindle provides an effective means for the online fabrication of microtool electrodes, thus eliminating secondary clamping errors. However, significant wear of the electrodes occurs during the micro-electrical discharge machining (micro-EDM) process, causing rapid degradation of usability. Therefore, for the practical application of micro-EDM in continuous manufacturing processes, it is essential to integrate electrode wear compensation into the spindle feed function. This study proposes a high-precision spindle head with a combined function of rotation and inchworm feed for micro-EDM with WEDG. The spindle head maximizes tool electrode length utilization with a unique arrangement of upper and lower clamps. The separate control of rotational drive and accuracy, as well as the servo feed for machining gap and inchworm compensation, enhanced the electrode’s rotational and feed precision. The measured radial runout is less than 3.9 μm, and the deviation angle of parallelism error equals 0.019°. Utilizing the tangential feed WEDG process, the diameter consistency of the prepared electrodes is less than 2 μm, and the consistency accuracy of electrodes in repeated production is less than 3 μm. Arrayed Φ 65 μm and Φ 40 μm micro-holes with great dimensional consistency are achieved using prepared Φ 55 μm and Φ 30 μm electrodes, respectively. Moreover, electrodes with noncircular cross sections were prepared to machine square and triangular-arrayed micro-holes with high shape and size accuracy. Using the developed servo scanning micro-EDM technology and a layered depth-constrained algorithm, we machined micro-patterns of gears, stars, and special Chinese characters for “Tsinghua University”, as well as arrayed hemispheres, pentagons, and hexagons. The dimensions and shapes are consistent with the design models, with the least cumulative depth errors less than 2 μm and shape errors primarily arise from the inevitable rounded corners due to electrode radius.

The full text can be downloaded at https://doi.org/10.1007/s40436-025-00556-x

Key words: Micro-electrical discharge machining (micro-EDM), Wire electro-discharge grinding (WEDG), Spindle head, Inchworm feed, Combined rotation, Error

Pei-Yao Cao, Hao Tong, Yong Li, Bao-Quan Li, Feng Yu. High-precision spindle head with combined function of rotation and inchworm feed for micro-EDM with WEDG[J]. Advances in Manufacturing, 2026, 14(2): 311-328.

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