Papers by Keyword: Ultrasonic Drilling

Abstract: A drill processing for the difficult to cut material such as ceramics, hardened steel, glass and heat-resistant steel is widely requested in the industrial world. Furthermore the drilling process becomes more and more difficult in the case of that the requested hole diameter is less than one millimeter. In order to achieve requirements for drilling process, ultrasonically assisted machining is applicable. Ultrasonic vibration assisted machining techniques are suitable to machine difficult-to-cut materials precisely. The ultrasonic vibration assisted sub-millimeter drilling process reduces the cutting forces and prevents severe wear of tools. However, it is difficult to observe directly the effect of vibration action because the process of ultrasonic drilling is dynamic instantaneous and micro cutting process. In this report, high speed camera with appropriately arranged polarized device realized the visualization of process of ultrasonic drilling based on the photoelastic analysis. For the conventional drilling, the stress distribution diagram showed the intensive stress occurred under the chisel and side wall. On the other hand, the ultrasonic drilling produced lower and stable cutting force and decreased the tool temperature.

Abstract: Drill processing of difficult-to-cut materials such as ceramics, hardened steel, glass and heat-resistant steel is widely required in the industrial world. Furthermore the drilling process becomes more and more difficult in the case of hole diameters less than one millimetre. In order to achieve the requirements for the drilling process, ultrasonically assisted machining is applicable. Ultrasonic vibration assisted machining techniques are suitable for machining difficult-to-cut materials precisely. However, the cutting process of ultrasonic drilling has not been clarified. It is difficult to observe directly the effect of vibration. The aim of this study is to observe the dynamic, instantaneous and micro cutting process. In this report, a high-speed camera with a polarized device, which is appropriately arranged, realized the visualization of the process of ultrasonic drilling based on photoelastic analysis. For conventional drilling, the stress distribution diagram showed that the intensive stress occurred in limited areas under the chisel because the chisel edge of the drill produces large plastic deformation. On the other hand, the ultrasonic drilling produced spread stress distribution and a stress boundary far away from the chisel. The photoelastic analysis showed the explicit difference of drilling processes.

Abstract: Engineering ceramics have been widely used in recent years because of its excellent performances. However, the high hardness and brittleness make it very difficult to process with high efficiency and good quality, especially in precision and ultraprecision machining. Therefore, a method of ultrasonic drilling and grinding is provided to the hole machining of Al¬2O3 engineering ceramics. In the paper, with different machining parameters, the surface roughness of micro hole in ultrasonic and traditional drilling and grinding is compared and analyzed. Moreover, the surface micro profile and the wear condition of drilling-grinding tool in ultrasonic and traditional drilling and grinding are observed through SEM. Finally, it is concluded that ultrasonic drilling and grinding is a kind of high efficient processing method adapting to micro holes of hard - brittle materials etc.

Abstract: The application of an ultrasonic vibration is one of promising means in machining micro-holes. In this study, the differences of in the geometric machining mechanism between the ultrasonic and the conventional drilling were investigated. Specifically, the uncut chip thickness before machining and the tool trajectories of the cutting edges were formulated and compared with machining results. Through the machining experiments, it was found that those these parameters well matched with the appearance of both the disposed chips and the machined surface. Furthermore, the results indicated that the change of uncut chip thickness resulted in decreased machining resistance as well as improvement of the machined surface