A high-density, super-high-aspect-ratio microprobe array realized by high-frequency vibration assisted inverse micro w-EDM

This study is focused on the fabrication of a high-density, super-high-aspect-ratio microprobe array using high-frequency vibration assisted inverse micro w-EDM (wire electric discharge machining). An inverse micro w-EDM design in which a brass wire ϕ20μm in diameter is located beneath the workpiece...

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Bibliographic Details
Published in:Journal of materials processing technology 2017-12, Vol.250, p.144-155
Main Authors: Chen, Shun-Tong, Yang, Shih-Wei
Format: Article
Language:English
Subjects:
Debris
Density
EDM electrodes
Electric discharge machining
Electric wire
Electrodes
Erosion rates
Form accuracy
Gravitation
High-frequency vibration assistance
Magnetic fields
Microprobe array
Microstructure
Piezoelectricity
Super-high-aspect-ratio
Vibration
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Summary:This study is focused on the fabrication of a high-density, super-high-aspect-ratio microprobe array using high-frequency vibration assisted inverse micro w-EDM (wire electric discharge machining). An inverse micro w-EDM design in which a brass wire ϕ20μm in diameter is located beneath the workpiece for bottom-up machining is devised. The wire is triggered to a high-frequency oscillation by a piezoelectric actuator thereby changing the flow regime of dielectric fluid and quickly sending out debris from the narrow spark-gap. The debris is rapidly removed via gravity decreasing debris concentration around the wire-electrode thereby reducing the probability of discharge-shorting and heat-accumulation. Combining magnetic force design and micro wire vibration-inhibition, wire-wriggling and wire-swaying are readily minimized. Three kinds of high-density, super-high-aspect-ratio microprobe arrays comprising: (1) straight-type, (2) wave-type, and (3) spanning-type are verified successfully. Studies show that each probe has highly consistent dimensional and form accuracy with aspect-ratio realized at104:1. Experimental results also demonstrate that processing time ‘with’ a high-frequency vibration assistance of 1.6 KHz is about 75–80% that of the time ‘without’ high-frequency vibration, validating inverse micro w-EDM with high-frequency vibration assistance enhancing machining efficiency of microstructure arrays. Additionally, the following aspects are evaluated in detail: wire-tension control, discharge energy, corner path designs, wire-running speed, vibration assistance effect, vibrational frequency, and side-erosion.
ISSN:0924-0136
1873-4774
DOI:10.1016/j.jmatprotec.2017.07.014