Electroformed microfluidic chip mold faces the problem of uneven thickness, which decreases the dimensional accuracy of the mold, and increases the production cost. To fabricate a mold with uniform thickness, two methods are investigated. Firstly, experiments are carried out to study how the ultrasonic agitation affects the thickness uniformity of the mold. It is found that the thickness uniformity is maximally improved by about 30% after 2 h electroforming under 200 kHz and 500 W ultrasonic agitation. Secondly, adding a second cathode, a method suitable for long-time electroforming is studied by numerical simulation. The simulation results show that with a 4 mm width second cathode used, the thickness uniformity is improved by about 30% after 2 h of electroforming, and that with electroforming time extended, the thickness uniformity is improved more obviously. After 22 h electroforming, the thickness uniformity is increased by about 45%. Finally, by comparing two methods, the method of adding a second cathode is chosen, and a microfluidic chip mold is made with the help of a specially designed second cathode. The result shows that the thickness uniformity of the mold is increased by about 50%, which is in good agreement with the simulation results.
Thickness nonuniformity is one of the prominent problems in the electroforming process of the metal microfluidic chip mold, which decreases the dimensional accuracy of the mold, and has a direct influence on the usability of the microfluidic chip. A novel method of auxiliary cathode for improving the thickness uniformity of electroformed mold is presented in this paper. Compared with the traditional method of the auxiliary cathode, a coplanar auxiliary cathode similar to the local microstructure of mold is used to fabricate the electroformed mold, and the thickness uniformity of electroformed mold is improved obviously. In addition, in order to determine the dimensions and placement of the auxiliary cathode, the computer-aided analysis is performed to simulate electroforming process. The simulated results show that with the help of a specially designed auxiliary cathode, the thickness uniformity is improved by about 53.2% compared with the result without the auxiliary cathode. Finally, based on the simulation, a microfluidic chip mold is fabricated by micro electroforming with the coplanar auxiliary cathode. The result shows that the thickness uniformity of the mold is improved by about 49.1%, which is in good agreement with the simulation result.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.