Papers by Keyword: Workpiece Vibration

Abstract: When processing materials using the milling technology, regenerative fluctuations of vibrations are the decisive factors, which limit productivity. In some case the size of the vibrations can cause shortened lifespan of the tool, decrease reliability and operational condition of the device, and subsequently case poor quality of the processed surface. Predicting the size of the vibrations between the milling machine and the work-piece is important as a lead for the users of the tool to select optimum depth of the cut and turning of the spindle, which leads to maximum rate of splinter removal. The extent of the research is focused especially on the process of monitoring, with the goal to analyze the size of the vibration at three places determined in advance - spindle head, work-piece and support, where rotation speed of the spindle change during the processing, as well as rate of splinter removal. By evaluating the results of experimental research, it is possible to determine adequate rotation speed of the spindle and depth of the cut, to achieve longest lifespan of the machine.

Abstract: Vibration-assisted machining (VAM) combines small-amplitude vibration with different machining process to improve the process fabrication quality. It has been applied to a number of machining processes, such as turning, drilling, grinding and polishing. The emphasis on this literature is the vibration-assisted abrasive machining (VAAM), which involves with finishing and grinding processes where VAAM have been applied to hard metal, brittle material and complex geometries products like optical molds. This paper presents different vibrating units in VAAM from tool vibration to workpiece vibration, which also includes different vibrating paths from linear to ellipse. Typical hardware systems used to achieve these vibratory motions are described too.

Abstract: Present study introduces low-frequency workpiece vibration during micro-EDM drilling of difficult-to-cut tungsten carbide with an objective to overcome the difficulty in flushing of debris and machining instability in deep-hole machining. The effects of vibration frequency, amplitude and electrical parameters on the machining performance, as well as surface quality and accuracy of the micro-holes have been investigated. It is found that the overall machining performance improves significantly with significant reduction of machining time, increase in material removal rate (MRR), and decrease in electrode wear ratio (EWR). The surface quality improves and the overcut and taper angle of the micro-holes reduces after applying the workpiece vibration in micro-EDM. The frequency and amplitude of 750 Hz and 1.5 μm were found to provide optimum performance.