Modeling and Testing on Material Removal Mechanism of Rotary Ultrasonic Machining

Abstract

The technology of rotary ultrasonic machining is the combination of regular ultrasonic vibration and rotation motion. It applies a pre-load on the tool through tool head with an axial direction vibration and high rotation motion along with the ultrasonic system. The material removal mechanism of rotary ultrasonic machining, a model setup of efficiency on material removal and machining influence on different processing parameters are analyzed in this article. By comparing four different materials PZT Piezoelectric Ceramics, organic glass, glass steel and red cooper on single ultrasonic and rotary ultrasonic machining testing, the stabilization of machining process and efficiency of machining was analyzed on rotary ultrasonic machining as well. The testing proves that the rotation motion can significantly improve the ultrasonic machining efficiency on fracture toughness material. Introduction Rotary ultrasonic machining is the new method of machining, which is combination of the motion of rotation and traditional ultrasonic machining [1]. It utilizes the composite reaction between the force of mechanical rotation during the grinding and cutting machining and high frequency of ultrasonic vibration. It not only overcomes the lower machining efficiency caused by single ultrasonic and avoids the high wearing resistance of grinding and cutting head[2], but also saves the suspension liquid of grinding particles. For the machining material, there is no requirement of material hardness and electrical conductivity [3]. The low reaction of thermal physical and effective avoiding thermal damage and micro cracks have a high application value in the machining of fracture toughness material. However, there is no clear conclusion on the efficiency of machining processing parameters for rotary ultrasonic machining. An efficiency model of material removal mechanism of rotary ultrasonic machining is set up, and the testing result of the influence of different materials for this machining method is analyzed in this article. Material Removal Mechanism of Rotary Ultrasonic Machining In Fig.1, rotary ultrasonic machining is applied the mechanical machining cutting liquid on the surface of tool and high frequency of ultrasonic vibration on the tool head and make a rotation around itself. The tool head is supplied by a constant pressure or speed by the tool. During the machining, on the one hand, the surface particles is hitting the tool with a high frequency under the ultrasonic[4], on the other hand, the high rotation of ultrasonic spindle under the electrical motor is forcing the mechanical cutting in the contact area between the cutting part and tool. Then the material removal mechanism is implemented under these two reasons [5]. The indentation occurs on the surface of part under the high frequency vibration hitting and then it continues to develop cracks as Fig. 2 (a). At the meantime, under the rotation of tool head, the particles scratch and damage the part surface as Fig. 2(b), finally the particles inside the cracks will be peel off under the hitting of inertia of rotation force, and cause the material removal as Fig. 2 (c) .