Session: AM3D1.1 - Current and Emerging Trends in AM

Paper Number: 159890

159890 - Selective Micro Laser Melting for Fabrication of Electronic Circuits 

Multi-material additive manufacturing (MMAM) has the potential to revolutionize the fabrication of prototype electronic circuit with a significant reduction in the chemical waste and production time. MMAM enables the creation of functional electronic circuits through the printing of freeform conductive traces and substrates. However, the polymer substrate imposes a limitation on the post-processing temperature of the deposited conductive inks or pastes, as exceeding the heat deflection temperature of the thermoplastic substrate results in deformation. The integration of post-processed conductive traces with a thermoplastic substrate thus presents a significant challenge. 

In this study, we introduce the Selective Micro Laser Melting (SMLM) technique for localized post-processing of conducting traces, thereby minimizing substrate deformation. This process is enabled by an in-house developed single-unit hybrid additive manufacturing machine capable of sequentially printing polymer substrates using filament-based extrusion and conductive traces using a pneumatic-based extrusion technique. The specific process parameters like laser spot-size, power, and scan speed are selected to ensures the controlled melting of the deposited material, preventing any deformation of the low heat deflection temperature polylactic acid (PLA) polymer substrate. The cross-section microscopic view of the conductive traces reveals regions with complete melting of the deposited solder paste embedded in the printed polymer substrate at desired locations. The conductivity of the melted traces on the printed substrate is measured using a two-probe method and compared with bulk metal conductivity. This approach enables the successful fabrication of embedded metallic interconnects and conductive traces within flexible, thin polymer substrate while achieving conductivity close to the bulk electrical characteristics of the metal. 

Presenting Author: Arun Kumar Sivakumar Indian Institute of Science, Bengaluru

Presenting Author Biography: Mr. Arun Kumar Sivakumar is pursuing a PhD in Design and Manufacturing from the Indian Institute of Science, Bengaluru. He holds a Master's in Additive Manufacturing from the National Institute of Technology, Warangal. He is working on multi-material additive manufacturing technologies. Mr. Arun received the I4AM conference Best Paper Award 2024 for his selective laser processing materials research.