Analysis on micro milling dynamics and stability

Official URL: http://192.168.1.20/record=b1378249 (Table of Contents)

Smaller sizes are becoming more and more necessary for industry. Literally, machining features less than one millimeter are called micro machining. Milling using small or mini tools is one of the most common manufacturing processes for production of precision products. As in the macro milling, milling with mini tools also suffer from well known unstable vibration problem which is called regenerative chatter. Chatter prediction models need certain process, tool and workpiece related information. Tool tip frequency response function FRF is the key input information for cutting dynamics and chatter stability analyses. The common method for determining macro tool tip FRF is the experimental modal analysis. However, in micro tools receptance coupling analysis is popular in the literature due to certain restrictions of experimental test method. This thesis is focused on determining dynamic parameters of miniature milling tools by modal testing methods which are crucial to determine the stability characteristics of the micro flat end milling. An indirect modal testing method is presented. Also stability limit prediction with a conventional model is compared with experimental results. Various chatter detection methods and milling conditions are tested. In process chatter detection problems and modelling difficulties related with the miniature tool geometry are reported. Tool dynamics prediction is done with certain accuracy. Although the thesis study lacks from solid results in the stability limit prediction, discrepancy analysis of the test data are done and it is a first step for further studies.