Injection Moulding Process Development and Yield Analysis for Different Microfluidic Chip Designs
SIMTech has developed a micro-injection moulding technology for manufacturing of thin-walled microfluidic chips (thickness < 0.8 mm ± 80 µm) with micro-feature structures (e.g. 10 – 200 µm), aspect ratio greater than 2 and warpage less than 50 µm over 75 mm span. The replica accuracy was maintained within ± 10% of the total channel width and depth for different insert design. Current production yield is 50%, improved from 30% previously, while the targeted production yield is at least 80% of the total production.
Contact PersonTong Kin Kong, Steven(steven@SIMTech.a-star.edu.sg)
These capabilities include (i) material selection, (ii) mould design and micro-insert fabrication, (iii) optimisation of process parameters and process window and (iv) methodologies for the evaluation of residual stress, replica accuracy, thickness and warpage.
Micro-injection moulding is the key technology for micro manufacturing due to its mass production capability and low production cost. It has been reported that micro-features (with feature size ranging from 10 – 200 µm) having an aspect ratio greater than 2 with a warpage requirement of less than 50 µm are difficult to achieve. In addition to the poor replica efficiency, the production yield for such microfluidic chip manufacturing is very low, usually less than 30%. Therefore, the main problem arises during micro-moulding of thin-walled structures parts usually results to high warpage issues and accumulated residual stress within the polymeric chips.
The team at SIMTech currently focuses on development of a micro-fabrication process for different foundry microfluidic chips design with shorter cycle time by optimizing the process parameters and mould design during micro-injection moulding process to improve the repeatability, within the requirement of overall warpage less than 50 µm with a targeted production yield of at least 80%.