Development of Audio Frequency Vibration Microforming System

Many researchers have developed several microforming technologies such as micro deep drawing, micro press forming, microforging, and extrusion for creating precise micropatterns on the surface of metal substrates, but they have found it difficult to avoid elastic recovery, which results in low formability and degradation of surface roughness and accuracy of three-dimensional formed profiles. The audio frequency vibration microforming system (AFV forming system) developed in this study can dramatically enhance not only the formability of metal substrates but also the accuracy of three-dimensional formed surfaces, because fast micro tramping action over a microdeformed region minimizes elastic recovery and removes several defects that occur in conventional microforming. The developed AFV system is mainly composed of a vertical hydraulic cylinder for macro movement and a vibratory tool actuated by an optimally preloaded lead zirconate titanate (PZT) stack, punches, and some structural compartments. In order to design the system optimally and determine the optimal process modes and conditions, several FEM analyses and experiments were performed. The experimental results of varying vibration schemes and processing conditions yielded the optimal process conditions and proved the validity of the developed novel microforming system.