MANUFACTURING TECHNOLOGY
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ULTRASONIC MACHINING
In ultrasonic machining, the tool vibrates at very high frequency i.e.20 KHz. Per second. Abrasive slurry is applied between the tool and work piece. By this, very minute particles of work piece are removed by erosion and abrasion. The tool is slowly fed on the work piece. The tool shape is reproduced in work piece. The ultrasonic equipment has a transducer, tool holder and the tool. The transducer has nickel laminations wound with a coil. A high frequency current is supplied to the coil of the transducer. The transducer converts this high frequency current into mechanical vibration. These mechanical vibrations are transmitted to the tool through the tool holder. The tool vibrates axially with amplitude of 0.05 mm and a frequency of about 20 KHz. Abrasive slurry is applied between the work surface and the tool. The slurry is made of a mixture of water and fine grains (800 to 1000 grit size) of aluminum oxide, silicon carbide or boron carbide. Because of the tool vibration, the abrasive grains in the slurry are hammered into the work surface. Hence by abrasion and erosion, the metal is removed from the work as minute particles. By this action, the shape of the tool is reproduced in the work. The tool is fed downwards very slowly. Maximum feed rate is 0.1 mm/sec. The tool is made 0.01 mm smaller than the required hole. The tool is made of soft ductile material such as soft steel, copper or brass. The tool holder is made of stainless steel. Dimensional accuracy up to 0.05 mm is possible. Applications: Ultrasonic machining process is applied:
1. for drilling holes in hard and brittle materials like ceramics, glass, boride, ferrite, carbides, carbides, precision stones like diamond and hardened steel.
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