Improvement of microfluidic chip mould thickness uniformity by ultrasonic agitation during electroforming process

The electroforming microfluidic chip mould faces the problem of uneven thickness,which influences the dimensional accuracy and performance of the mould, and increases the production cost. With the aim of fabricating a microfluidic chip mould with uniform thickness, electroforming with ultrasonic agitation is investigated to improve the thickness uniformity of the mould. Firstly, numerical simulation is performed using COMSOL multiphysics software to analyze the thickness distribution of the mould after 2 h electroforming. And based on the simulation result, a photomask is designed. Secondly, with the photomask, electroforming experiments are carried out to study how ultrasonic agitation affects the thickness uniformity of the mould. It is found that the ultrasonic agitation can improve the thickness uniformity of the mould. With 200 W ultrasonic agitation, the effect of ultrasonic frequency on the thickness uniformity increases in the order of 200 kHz＞80 kHz＞120 kHz. And with 200 kHz ultrasonic agitation, the effect of ultrasonic power on the thickness uniformity increases in the order of 500 W＞200 W＞100 W. Compared with the thickness uniformity without ultrasonic agitation, with 200 kHz and 500 W ultrasonic agitation, the thickness uniformity of the mould is increased by about 30%.