Sealing of complex microfluidic labs-on-chip arrangements is key for its functionality, the price for the sealing is key for its market penetration. Manufacturing of polymer lab-on-chip devices actually relies on adhesive bonding which is little flexible and costly. Accuracy specifications move towards 50 μm total error over distances that exceed 50 mm which cannot be achieved in laser-based welding today because of the multi part alignment of polymer carrier and sealing foils. Throughput is limited by time-consuming and costly alignment operations, difficulties for automation, and defective parts. Typical defects are failure in seam position, inclusions, pores and very often variable seam quality in intricate curvilinear welds.
PAPS aims at a laser-based equipment that integrates loading, handling, alignment welding and final inspection in one go. The integration of all these steps ensures that parts are placed to specification and that in the case of detected errors, the part can be correctively processed. The digital integration of all information at ICT level ensures fast setup for new products, reliable selection of processing parameters and continuous documentation of the production process which is key in medical applications. The final inspection ensures that the part is released with an individual quality documentation and thus eases the traceability of the product. Once the PAPS system is fully validated, the transfer to other segments such as thin polymer film applications in electronics will be exploited.
A working prototype of a laser welding system has been produced in PAPS, demonstrating its operation by laser sealing a real microfluidic device by SENSLAB. Overall accuracy with PAPS laser process has been verified to be better than 10µm. It ensures great repeatability, producing high quality welding seams as thin as 60 µm, while providing a very high productivity rate: under 5 seconds are required to weld a whole complex microfluidic chip, granting plenty of time for the handling and inspection processes.