Joining tool unit

A joining tool unit comprising a movable tool, a tool counter-element, a drive unit, a light guiding system, a light source and a control unit, wherein the movable tool and the tool counter-element are arranged on the joining tool unit opposite each other, wherein the light guiding system is configured to guide a light of the light source in the direction of a joining location of a workpiece when the workpiece is arranged on the joining tool unit, wherein the movable tool can be moved in the direction of the tool counter-element by the drive unit, wherein, in the state in which a workpiece is arranged on the joining tool unit, the workpiece is joined by the movement of the movable tool in the direction of the tool counter-element, wherein the control unit is configured to control and/or adjust the drive unit, wherein the control unit is configured to control and/or adjust the light source and/or a component of the light guiding system, wherein the joining tool unit is configured so that a movement of the movable tool in the direction of the tool counter-element is started and at the same time or chronologically afterwards irradiation or illumination of the joining location with the light of the light source is ended, wherein the control unit is configured so that irradiation or illumination of the joining location of the arranged workpiece with the light of the light source is ended before the movable tool can be introduced into a light beam of the light of the light source during its movement in the direction of the tool counter-element.