Laser pulse energy adjustments are motivated by an understanding of the effect of laser pulse width variations among different lasers on satisfying a quality metric associated with a laser-processed target. An interruption control period is initiated based upon, at least in part, the interruption control initiation trigger. A ground reaction force plane is specified based on the sensed ground reaction force and a normal vector perpendicular to the ground reaction force plane is calculated. According to the invention, the motorized spindle unit is seated on the slide with resilient elements that accept the weight of the motorized spindle unit and are movable only in the direction of processing.