Micro-Shaping of Pure Aluminum by Intermittent Ultrasonic Oscillation Assisted Wire Electrochemical Micromachining with an Ultra-Low-Concentration Mixed Electrolyte

Abstract

Sacrificial mandrels and micro-components made from pure aluminum have considerable application potential for fabricating terahertz micro-cavity components and for MEMS. Although WECMM has significant advantages in micro-shaping micro-components from difficult-to-machine materials, high-quality micro-shaping of pure aluminum has always been very challenging due to its extremely high chemical activity in an aqueous solution. This study analyzes the electrochemical characteristics of pure aluminum and the corresponding machining experiments by traditional WECMM in various electrolytes, and manufactures a high-quality micro-slit with a short machining path in the obtained ultra-low-concentration mixed electrolyte. However, in a continuous long-term WECMM with a long machining path, poor mass transport leads to the accumulation of bubbles around the machining area and the deposition of insoluble products on the wire surface that reduce the machining stability and machining accuracy. Therefore, a mass transport method of using intermittent ultrasonic oscillation is proposed. The principle was expounded, systematic comparative experiments demonstrated the effectiveness of this method in continuous long-time WECMM in improving the machining stability and machining accuracy. Finally, a rectangular mandrel of pure aluminum with a path length greater than 10,000 μm was fabricated. After dissolving the rectangular mandrel, a terahertz hollow-core rectangular waveguide micro-cavity was produced.

Application of Nanofluid Electrochemistry in Heat Dissipation of Permanent Magnet Synchronous Motors

“…A little layering phenomenon has also appeared in the test tube after shaking for 2 hours, and a little flocculent material floats. e phenomenon shows that ultrasonic oscillation can effectively improve the stability of nanofluids, and the effect on the stability of nanofluids varies with the oscillation time, it is not that the longer the oscillation time, the better [20].…”

Micro-Shaping of Pure Aluminum in Long-Duration Wire Electrochemical Micromachining Using Bipolar Nanosecond Pulses

“…Recently, pure aluminum microstructures have also been applied in manufacturing terahertz microcavity components. For example, high-working-frequency terahertz hollow-core rectangular metal cavities can be manufactured using a high-quality pure aluminum sacrificial mandrel and its selective chemical dissolution [ 2 ].…”

“…WECMM has been successful for fabricating high-quality three-dimensional microstructures from a wide range of materials, such as pure nickel [ 11 ], stainless steel [ 12 ], cobalt-based alloys [ 13 ], and zr-based amorphous alloys [ 14 ]. Recently, high-quality three-dimensional micromachining of pure aluminum has been achieved through WECMM, but this is possible only in short-duration WECMM [ 2 ]. With the increasing demand for long-track three-dimensional microstructures of pure aluminum, it is extremely important to improve the machining stability and machining accuracy in long-duration WECMM of pure aluminum.…”

“…In long-duration WECMM, machining stability and machining accuracy will be reduced, as observed during the WECMM of some metal materials, such as pure aluminum, stainless steel, and metallic glass [ 2 , 15 , 16 ]. During long-duration WECMM of long-track microstructures, the bubbles and insoluble electrolysis products discharged from the machining gap do not diffuse easily owing to the limited mass transfer in the current WECMM process.…”

Electrochemical Deposition of Pure-Nickel Microstructures with Controllable Size

“…Various types of pure-nickel microstructures have been used successfully in micromachines and microsystems, such as the microscopic coil springs of semiconductor devices [ 3 ], the microgear reducer of a microscopic transmission system [ 4 ], the microrotor of a microgyroscope [ 5 ], and the microcantilevers of hydrogen sensors [ 6 ]. Recently, the integral fabrication of a high-working-frequency terahertz rectangular waveguide cavity was reported, and this novel process depends on the manufacture of a pure-nickel sacrificial rectangular mandrel and its selective chemical dissolution [ 7 , 8 ]. The transmission of terahertz signals can be improved significantly through such fabrication of such a cavity, and so a pure-nickel sacrificial rectangular mandrel with controllable size and good surface roughness and fillet radius has great application potential in the manufacturing of terahertz microcavity components.…”