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

• US 10,369,661 B2
• Filed: 02/25/2015
• Issued: 08/06/2019
• Est. Priority Date: 02/25/2015
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Technology Research Association for Future Additive Manufacturing
• Inventors: Ohno, Hiroshi, Sasaki, Yuji, Sasaki, Mitsuo, Obara, Takashi, Masukawa, Kazuyuki
• Primary Examiner(s): Ross, Dana
• Assistant Examiner(s): Baillargeon, Joseph M
• Application Number:
  US14/889,088
• Publication Number:
  US 20160368097A1
• Time in Patent Office: 1,623 Days
• Field of Search: 219 7612, 219 78, 21912178- 79, 21912178- 80, 21912175, 359849, 359811
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B23K 26/0736 into an oval shape, e.g. elliptic shape
• CPC Class Codes: B23K 26/0869 Devices involving movement of the laser head in at least one axial direction
• CPC Class Codes: B23K 26/144 the fluid stream containing particles, e.g. powder
• CPC Class Codes: B23K 26/342 Build-up welding
• CPC Class Codes: B23K 26/702 Auxiliary equipment
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B29C 67/00 Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes

Abstract

An optical processing head capable of downsizing an apparatus while increasing the shaping accuracy of optical processing is disclosed. The optical processing head performs processing while moving, in a predetermined moving direction on a processing surface, an optical spot formed by condensing light emitted by a light source. The optical processing head includes an optical element that condenses light emitted by the light source to generate the optical spot of a shape elongated in the moving direction of the optical spot. Part of the optical spot is set as a processing region, the front side and/or rear side of the processing region in the moving direction is set as a pre-heating region and/or post-heating region, and a processing target object before and/or after processing in the region is heated.

Claims

1. 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.

2. The optical processing head according to claim 1, wherein said first optical element pivots on a plane perpendicular to the optical axis of the parallel light to change the shape of the optical spot following a change of the moving direction.

3. A method of controlling the optical processing head according to claim 2, the method comprising the steps of:

pivoting the first optical element on the plane perpendicular to the optical axis of the parallel light in accordance with the moving direction of the optical spot to heat a processing target object before and after processing in the processing region; and

pivoting the transparent plate with the pivot shaft as an axis to move the optical spot onto the processing region in a direction perpendicular to the moving direction by refracting the parallel light through the transparent plate.

4. A non-transitory computer-readable medium storing a program which, when executed by a computer, causes the computer to perform a method of controlling the optical processing head according to claim 2, method comprising the steps of:

pivoting the first optical element on the plane perpendicular to the optical axis of the parallel light in accordance with the moving direction of the optical spot to heat a processing target object before and after processing in the processing region; and

pivoting the transparent plate with the pivot shaft as an axis to move the optical spot onto the processing region in a direction perpendicular to the moving direction by refracting the parallel light through the transparent plate.

5. The optical processing head according to claim 1, wherein said first optical element slides in a direction perpendicular to the moving direction in accordance with a movement of the parallel light in the direction perpendicular to the moving direction based on a change of the angle of said transparent plate.

6. The optical processing head according to claim 1, further comprising a second optical element selected from the group consisting of a cylindrical lens and a toric lens that further condenses light having passed through said first optical element.

7. An optical machining apparatus comprising:

an optical processing head defined in claim 1;

a light source; and

a light transmitting portion that transmits light emitted by said light source to said optical processing head.

8. The optical processing head according to claim 1, wherein an input angle of the parallel light to the transparent plate is identical to an output angle of the parallel light from the transparent plate.

9. The optical processing head according to claim 1, wherein the first optical element is disposed closer to the processing surface than any other optical element in the optical processing head.