High Speed Micro Machining Processes Analysis for the Precision Manufacturing

This work shows the results of high frequency force measurement for micro milling operations on hardened steel with rotational speeds up to 110,000 rpm using a modified high frequency dynamometer with optimally reduced pre-located mass between sensor and workpiece. This development allows for a significant increase of the natural frequency both in shear direction (aprox. 9 kHz) as well as in longitudinal direction (up to 25 kHz). Additionally, a completely new developed hexapod dynamometer with extremely high sensitivity (up to 115 pC/N) for micro processing forces will be shown as well. Further on, aiming to expand the knowledge on EDM process forces, results of measurements using two different force sensors (aprox. 20 kHz and 200 kHz) with micro-electrodes down to 0.4 mm in diameter will also be shown and analysed with the aid of high speed camera images of the discharge gap region. Those experimentations made simultaneously with the single discharge force measurements will help identifying the characteristical behavior of the measured signal proving their suitability to monitor an unconventional process such as EDM.