Communication—Fabrication of Micro-Holes in PMMA Using Micro-ECDM Process: Geometric Characteristics and EC Discharge Behaviour

• Published in: Journal of the Electrochemical Society 2024-05, Vol.171 (5), p.53506
• Main Authors: Arab, Julfekar, Sharma, Priyaranjan, Chen, Shih-Chi
• Format: Article
• Language: English
• Subjects: discharge; ECDM; micro-fabrication; PMMA; tool-electrode
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1945-7111/ad4a0d

High-quality micro-features with low production cost are in high demand for the development of cost-effective microfluidic devices. In this work, we present a scalable and cost-effective fabrication process for fabricating blind micro-holes in PMMA substrates via micro-electrochemical discharge machining (Micro-ECDM) for the first time. By providing the suitable applied voltage (V a ), uniformity of the electrochemical (EC) discharges and subsequent geometric characteristics of the micro-holes can be controlled. The stable and unstable EC discharge zones and micro-hole machining quality for different V a and tool conditions have been identified. For unstable and non-uniform EC discharge zone at V a of 26 V, the variation in the micro-hole output parameters is higher compared to stable and uniform EC discharge zones at V a of 28 V and 30 V. Based on the results, micro-holes with appropriate quality have been fabricated and characterized. Micro-holes formed in PMMA substrates using low-cost micro ECDM process for first time. Critical and applied voltage (V C and V a ) along with mean discharge current (I d ) influences micro-hole quality. Lower applied voltage (V C  + 2) results into unstable discharges leading to poor-quality holes. The recommended value of the Va for uniform discharges and good quality holes in PMMA is ≥V C +4. Machining with used tools degrades the hole quality in PMMA.