The prevalence of micro-holes is widespread in mechanical, electronic, optical, ornaments, micro-fluidic devices, etc. However, monitoring and detection tool wear and tool breakage are imperative to achieve improved hole quality and high productivity in micro-drilling. The various multi-sensor signals are used to monitor the condition of the tool. In this work, the vibration signals and cutting force signals have been applied individually as well as in combination to determine their effectiveness for tool-condition monitoring applications. Moreover, they have been used to determine the best strategies for tool-condition monitoring by prediction of hole quality during micro-drilling operations with 0.4 mm micro-drills. Furthermore, this work also developed an adaptive neuro fuzzy inference system (ANFIS) model using different time domains and wavelet packet features of these sensor signals for the prediction of the hole quality. The best prediction of hole quality was obtained by a combination of different sensor features in wavelet domain of vibration signal. The model’s predicted results were found to exert a good agreement with the experimental results.

This research paper aims to investigate the drilling capabilities of the sintered powder metallurgy parts. Due to their special properties, these materials are of distinguished importance in today's world. Exploiting said properties enables us to create self- lubricant bushing as well as special alloys. In order to evaluate the investigated parameters, comparative experiments were conducted. Both the tool materials and the application of cooling varied in the experiments, in the framework of which cutting force, drilling torque and tool wear were measured. The hole geometry (diameter accuracy and circularity) was also checked. Owing to the environmentally friendly machining conditions, the experiments can be carried out by means of dry machining, air cooling and minimal quantity lubrication. According to our results, it was the cutting force and the tool wear that the cooling of the tool had the greatest effect on in the case of powder metallurgy materials