Abstract
In this report, it is analyzed that a super precision machining in long and small diameter's hole boring can be realized by combining the main spindle system with the hydro-static bearing and the effect of improvement of the boring bar's rigidity using the insensitive vibration cutting mechanism. For this long hole boring, a new special ultrasonical torsional vibration boring device can be created. This device fixed on the carriage of the newly developed vibration cutting lathe enable to bore a hole of 12 mm in diameter and 90 mm in length. This analytical result has been confirmed by the experiments under the many cutting conditions. The main cutting conditions are as follows : the vibrating direction of tool ; in the same direction as that of cutting, frequency; 29.3 kHz, amplitude; 20 μm, cutting speed; 8-20 m/min, depth of cut ; 0.005-0.03 mm, feed; 0.02-0.08 mm/rev, cutting tool material ; carbide tool K 10, tool geometry; rake angle, 0°, 10°, 20°, duralumin σB=28 kg/mm, brass σB43 kg/mm, carbon steelσB= 66 kg/mm, are used as work materials. The main results are as follows : 1) A new special ultrasonical torsional vibration boring device for long and small diameter's hole boring can be created. 2) Machined surface roughness almost coincides with the theoretical roughness. 3) Roundness of 0.8-1 μm are obtained. 4) The smooth machined surface on which iridescent surface is generated is produced. 5) By this study, it is proved that this new lathe has the possibility of super precision machining in long and small diameter's hole boring.
