Fabrication of a micro-tool in micro-EDM combined with co-deposited Ni–SiC composites for micro-hole machining

Abstract

This paper presents an in situ process using a micro-tool in micro-electro-discharge-machining combined with co-deposited Ni–SiC composites to drill and finish micro-holes. During the machining process, a micro-tool is fabricated by wire electro-discharge grinding and electrodeposition. The experimental result shows that the suitable parameters obtained for fabricating micro-tools for Ni–SiC composite coatings are a current density of 7 A dm−2, positive ring hole diameter of 5 mm, SiC particle size of 4 µm, SiC particle concentration of 10 g l−1, rotational speed of 15 rpm and surfactant cetyltrimethylammonium bromide concentration of 150 ppm. When using this method, the micro-tool is provided with a smooth Ni layer, uniform particle distribution and suitable particle adhesion quantity. Then, circular micro-holes are machined in high nickel alloy. Scanning electron microscopy micrographs and atomic force microscopy measurements show that micro-grinding can improve the surface roughness from 1.47 µm Rmax to 0.462 µm Rmax.

Fabrication of a micro-spherical tool in EDM combined with Ni-diamond co-deposition

“…For the amount of adhered diamond particles, there is no obvious variation with co-deposition time as it is deposited layer by layer. As in a previous study [5], current density and co-deposition time are main factors for coating thickness in co-deposition. In addition, the main factors to influence the amount of adhered diamond particles are current density, rotational speed and particle concentration.…”

“…The inner diameter of the ring is 5 mm. Finally, the micro tool is utilized for machining a micro cavity with alumina slurry (particle size of 1 µm alumina added into lubricant in weight ratio 2:1) and the operational conditions are shown in table 5.…”

“…For the diamond coating process, although chemical vapor deposition (CVD) can grow a high-quality diamond film on the tool surface [3], the fabricating cost is higher. However, electrodeposited composite coatings have been extensively employed in various engineering applications such as improving wear resistance, corrosion resistance, dispersion hardening, self-lubrication and for grinding or cutting tools [4][5][6]. Such electrodeposited composite coatings consist of a metal or alloy matrix containing a dispersion of secondphase particles such as diamond, SiC and alumina particles [7].…”

Improvement of the Adhesion and Diamond Content of Electrodeposited Cu/Microdiamond Composite Coatings by a Plated Cu Interlayer

“…The miniaturization of cutting tool has increased the demands for manufacturing precision. Electrical discharge machining is often used to manufacture various types of micro-parts [ 1 ], as well as micro-cutting tools (e.g., those for micro-drilling, micro-cutting, and micro-repair). As the substrate is supposed to be the micro-milling/electro-machining tool to cut brittle or fragile workpieces, the application of brass can thus result in a better toughness and is still excellent to absorb the impact from contact.…”

Electrophoretic deposition characteristics of an electrical discharge machined micro-tool for micro-hole polishing in quartz

“…According to these studies, EPD can be utilized for polishing materials such as stainless steel and silicon wafers. Unlike the composite electroplated coating [9], the electrophoretically deposited layer was structurally less compact because the layer deposited by electrophoresis adheres to the micro-tool by electrostatic force. In this paper, SiC particles were coated by EPD onto a micro-tool for polishing micro-holes in quartz to improve their surface roughness.…”