Influence of helical electrode and its structure on EDM small hole machining

Hu, Yizhou; Wang, Han; Wang, Zhenlong

doi:10.1007/s00170-022-10488-6

Cited by 2 publications

(3 citation statements)

References 23 publications

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“…conducted very similar but more in-depth studies than UHLMANN ET AL., and like the works discussed so far, they did not apply active flushing. Both author groups found a groove or flute angle of α g = 60 • to be optimal in intervals of 30 [12,39]. HU ET AL.…”

Section: State Of the Artmentioning

confidence: 97%

“…Tools with external helical geometries in general are almost without exception used in conventional drilling or milling, e.g., twist drill geometries or axial slots for chip flow. In the field of EDM, however, only a few works dedicated to the use of helical external geometries exist so far [2,7,27,33,[37][38][39]. In addition, the so-called helical electrodes have found their way into research on electrochemical machining (ECM) [40][41][42][43], as well as hybrid processes [44,45].…”

Section: State Of the Artmentioning

confidence: 99%

“…stated that in most cases, the larger groove width and groove depth allow for higher machining speeds and lower EWR while avoiding severe bore shape and surface defects. However, basic numerical simulations using a rather simple mesh without dissolving the boundary layer and no further information about the model or software used led to the conclusion that the dielectric is sucked into the helical groove at the bottom of the bore and moves upward in a spiral path [39]. UHLMANN ET AL., however, more generally pointed out that minimum groove depths d g ≥ 0.3 mm and groove angles α g ≥ 45 • are needed for tool electrodes with an outer diameter of d o = 3 mm to improve the ED drilling process.…”

Section: State Of the Artmentioning

confidence: 99%

See 2 more Smart Citations

Helical Electrodes for Electro-Discharge Drilling: Experimental and CFD-Based Analysis of the Influence of Internal and External Flushing Geometries on the Process Characteristics

Uhlmann,

Polte,

Yabroudi

et al. 2023

JMMP

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The electro-discharge (ED) drilling of precision boreholes in difficult-to-machine materials, particularly with respect to the cost-effectiveness of the overall process, is still a challenge. Flushing is one key factor for the precise machining of boreholes, especially with high aspect ratios. Therefore, the influence of internal and external flushing geometries for six types of brass tool electrodes with a diameter of 3 mm with and without a helical groove was analyzed experimentally and numerically. Using this helical external flushing channel, drilling experiments in X170CrVMo18-3-1 (Elmax Superclean) with an aspect ratio of five revealed a material removal rate (MRR) that was increased by 112% compared with a rod electrode, increased by 28% for a single-channel tool electrode and decreased by 8% for a multi-channel tool electrode. Signal analyses complemented these findings and highlighted correlations between classified discharge event types and the experimental target parameters. Amongst others, it was verified that the arcing frequency ratio drove the electrode wear rate and the beneficial frequency ratio correlated with the MRR and the surface roughness Ra. Sophisticated 3D computational fluid dynamics (CFD) models of the liquid phase were introduced and evaluated in great detail to demonstrate the validity and further elucidate the effect of the external flushing channel on the evacuation capability of debris and gas bubbles. The presented methods and models were found to be suitable for obtaining in-depth knowledge about the flushing conditions in the ED drilling working gap.

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Section: State Of the Artmentioning

confidence: 97%