Optical processing head, optical machining apparatus, and optical processing method

An optical processing head that performs processing while moving, in a predetermined moving direction, an optical spot formed on a processing surface made by deposited powder material by condensing light emitted by a light source, comprising a plurality of optical elements including:

• a parallel light conversion element that converts the light emitted by the light source and exited from an incident end of an optical fiber having a first diameter to a parallel light in a circle shape having a second diameter;
• a first optical element which is a cylindrical lens or a toric lens that condenses the parallel light received from the parallel light conversion element in a direction perpendicular to the moving direction and forms the optical spot in an elliptical shape with a major axis in the moving direction, and
• a transparent plate that is arranged between the parallel light conversion element and said first optical element, receives the parallel light, refracts the parallel light, and exits the refracted parallel light to said first optical element,
• wherein the transparent plate comprises a pivot shaft on a plane perpendicular to an optical axis of the parallel light, about which the transparent plate pivots to change an angle formed by the parallel light and said transparent plate, to refract and shift the parallel light, and to move the optical spot in a direction perpendicular to the moving direction,
• wherein a part of the optical spot is set as a processing region, which corresponds to a material convergent region on which the optical processing head is configured to deposit the powder material as a powder spot, and
• wherein a front side of the optical spot from the processing region in the moving direction is set a pre-heating region to reduce a thermal stress caused by an abrupt temperature rise of a processing target object by heating the processing target object before processing in the processing region, and a rear side of the optical soot from the processing region in the moving direction is set a post-heating region to reduce a residual stress caused by an abrupt temperature drop of the processing target object by heating the processing target object after processing in the processing region.