Provided is an apparatus that includes a high energy beam configured to make a first weld at a first position on a workpiece; at least one deflection lens configured to deflect the high energy beam so as to cause the high energy beam to make a second weld at a second position; at least one focusing lens configured to focus the high energy beam; at least one astigmatism lens; and at least one controller. The controller is configured to shape the high energy beam so that the shape of the high energy beam on the workpiece is longer in a direction parallel to a deflection direction of the high energy beam than in a direction perpendicular to the deflection direction of the high energy beam. A length ratio is varying as a function of the power of the energy beam, while the width in the perpendicular direction is constant.