Tool track display device for displaying track of tool

A tool track display device which displays a track of a tool of a machine tool wherein a workpiece is machined through reciprocal and relative movement between the tool and the workpiece by at least one drive axle using a numerical control device, comprising;

• a position information acquisition unit which acquires position information created in the numerical control device at a predetermined control cycle or position information of the at least one drive axle from the position sensor,
• a tool coordinate calculation unit which calculates coordinate values of the tool based on the position information of the at least one drive axle and information regarding the mechanical structure of the machine tool,
• a display attribute modification unit assigning a display attribute to the position information of the at least one drive axle from the position sensor based on the motion direction of the tool,
• a display unit which displays the track of the tool based on the coordinate values of the tool calculated by the tool coordinate calculation unit and the display attribute assigned by the display attribute modification unit;
• an inverse position acquisition unit which acquires an inverse position in which the motion direction of the tool is inverted from the numerical control device or an operation program of the machine tool, wherein said display attribute modification unit modifies the display attribute of the tool track in accordance with the inverse position.