EXPERIMENTAL DEFINITION OF BASING ACCURACY AND TOOL FASTENING
There are presented results of experimental investigations allowing the definition of factors (parameters) influencing the accuracy of basing and fastening a tool in a machine spindle. The plant design developed allows modeling the work of elements and mechanisms of a spindle unit of a jig-boring machine (JBM) at the moment of tool changing. The series of experiments carried out allowed drawing the following conclusions: - the accuracy of a tool installation in a machine spindle depends upon its angular position in a spindle taper; - angular errors of a tool cone element decrease a rigidity of a “spindle-tool” subsystem by 10…15%; - elastic movements in the area of a contact increase by 2-2.5 times at the presence of ovality in the cross-section of a holder (at ovality 18mkm); - the accuracy of tool location in a spindle increases with the increase of an axial tightening force (recommended tightening force - 3 ≤ Ptight. ≤ 5kN); - the holder operation results in the rigidity decrease of a tool system by 10…15% (operation term - 5 years).