Machining and Characterization of Channels on Quartz Glass using Hybrid Non-conventional Machining Process µ-ECDM

Abstract

Electrochemical Machining (ECM) and Electro Discharge Machining (EDM) are commercialized non-conventional machining processes due to its high accuracy of machining advance engineering conductive materials which are otherwise difficult with conventional processes. On combining ECM: etching and EDM: erosion, a hybrid technique called Electro Chemical Discharge Machining (ECDM) is used to machine non-conductive engineering materials like soda-lime, borosilicate, pyrex glasses, etc. Quartz glass is one of the hardest glass materials to process features on it and it widen the scope of its application in the field of microfluidic devices. Hence, machining of channels was carried out with 350 µm diameter tungsten carbide (WC) tool on 4000 µm thickness quartz glass for a length of 10,000 µm using developed micro-ECDM (µ-ECDM) experimental setup. The machining condition chosen was Voltage (V) of 60 V, Duty Factor (DF) of 60%, 20 wt% Sodium Hydroxide (NaOH) Electrolyte Concentration (C), and 0.01 mm/s feed rate (FR). Investigation was carried out to know the effect of varying number of machining passes for 200 µm depth on responses like material removed (MR), surface roughness (R_a), tool wear (TW), depth and width of the channel. Channel machined with 2 machining passes (100 µm/pass) showed better responses of a higher depth of 290 µm, MR of 2.77 mg, and lower  R_a of 1.786 µm with a width of 480 µm and tool wear (TW) of 1.36 mg as compared to channels machined with 1 machining pass (200 µm) and 4 machining pass (50 µm/pass). Further machining of channels with 2 pass was carried out to engrave letters and square wave channels formed on quartz glass may be used as microfluidic channels.