Abstract: Micro-spring is an important actuating component used widely in microelectromechanical systems. It is important to develop micro-forming techniques for manufacture of micro-springs with high-fatigue life. The effects of duty cycle, current density, and power properties on the quality of micro-electroforming planar micro-springs are studied. The process is optimized using an orthogonal experiment in order to achieve the high dimensional accuracy and fatigue properties of the planar micro-springs and meet the demand of microelectromechanical systems. The result shows that the fatigue property of micro-spring decreases as the duty cycle increases. Fatigue property of planar micro-spring prepared by double pulse power is superior to the one that prepared by direct current power and single pulse power. The optimal process is to use double pulse power, 3 A/dm² current density, 10% positive duty cycle, and 10% negative duty cycle. The fatigue life of planar micro-spring can reach 517 times under the constant displacement of 0.2 mm.

Key words: ordnance science and technology, planar micro-spring, micro-electroforming, fatigue property, orthogonal experiment