Patent ID: 7487004

Claim:
A tool selection method, in a machine tool including a tool rest movable along first and second control axes orthogonal to each other, for automatically selecting a desired tool from a plurality of tools mounted on said tool rest in a parallel arrangement laid in a first control-axis direction with respective tips thereof being oriented in an identical direction, said method comprising: setting a standard tip position ingerent to said tool rest; setting a clearance distance for spacing said tips of said tools from a workpiece during tool selection; determining tip distances of all of said tools mounted on said tool rest, each tip distance being defined from said standard tip position to an actual tip position on said tool rest; identifying a maximum tip distance among said tip distances, in relation to a currently selected tool as to be firstly used, a next designated tool as to be secondary used and an intermediate tool, if any, disposed between said currently selected tool and said next designated tool, in said all of said tools; moving said tool rest in a second control-axis direction, after a machining operation using said currently selected tool is completed, and placing said tool rest at a tool-change starting position where a tip of said currently selected tool is spaced from the workpiece along said second control axis by a distance provided by adding said clearance distance to a difference between said maximum tip distance and a tip distance of said currently selected tool; moving said tool rest from said tool-change starting position in said first control-axis direction, and placing said tool rest at a tool-change terminating position where a tip of said next designated tool is aligned with the workpiece in said second control-axis direction; and moving said tool rest from said tool-change terminating position in said second control-axis direction, and placing said tool rest at a tool-selection completing position where said tip of said next designated tool is spaced from the workpiece by said clearance distance along said second control axis.