Experimental investigation of replication accuracy of polymer-based microfluidic chip fabricated through induction-assisted hot embossing and parametric optimization through nature-inspired algorithms

Abstract

Hot embossing (HE) creates micron-scaled patterns on a polymer substrate. Conventional-HE faces a long cycle-time issue and reduces productivity. An induction-assisted HE (IHE) setup was developed in-house to solve this issue. A microfluidic chip was made using an in-house developed setup on polymethyl methacrylate. Micro-features on aluminum-6061 mold were made using fiber laser machining instead of photolithography, followed-by reactive ion etching or electroplating to save both costs and time. Accurate micropattern replication is vital for HE. Embossing factors affect replication accuracy. Less deviation in micro-channel depth improves replication accuracy. The experimental data was gathered via L27 orthogonal array. Linear regression was used to connect process parameters and response variables. The embossing temperature affects micro-channel depth by 79.78%. Particle swarm optimization, artificial bee colony (ABC), firefly algorithm (FA), and grey wolf optimization (GWO) optimized IHE process parameters. Firefly algorithm outperformed. The FA converged in four iterations, whereas particle swarm optimization took 12 and ABC 38. All methods (excluding GWO) reached 6.5809 μm, the global best. A confirmation test shows optimal operating conditions reduce embossed micro-channel depth variation from 126.758 μm to 7.0327 μm and improve replication accuracy from 19.94% to 95.50%. The predicted and experimental embossed micro-channel depth deviation percentile error is 6.86%. An IHE setup was used to bond the microfluidic chip. The microchannel in the microfluidic chip was treated with vaporized bonding before thermal bonding to prevent deformation/blocking. No blue ink leaked during the testing of the manufactured microfluidic chip, showing acceptable quality.

Fabrication of hydrophobic optical diffuser film for LED lights through induction-aided hot embossing using micro-textured mold fabricated by μ-WEDM: parametric analysis, wettability study and optical characterization

“…The maximum height was achieved in the case of PC substrate, followed by PET and PMMA substrate. The height of the embossed V-groove decreases from 256.01 μm to 229.44 μm as T de increases from 30 °C to 70 °C. The replication rate was evaluated by putting these values in equation (1); the replication rate was decreased from 86.86% to 77.85%.…”

“…The heating and cooling cycle consumes most of the time in the hot embossing process and makes the process inefficient for mass production [24]. To overcome this difficulty, recently, researchers modified the traditional hot embossing setup and developed the infrared-assisted-HE [25], Ultrasonic-aided-HE [26], CO 2 -aided-HE [27,28], Induction-aided-HE (IHE) [29][30][31] and, laser-assisted-HE [32]. In the present work, the authors have developed an IHE setup in-house, and its performance was compared with traditional-HE.…”