Machining device and machining method

Patent metadata

Field	Value
Publication number	US-9757816-B2
Application number	US-201314655281-A
Country	US
Kind code	B2
Filing date	Nov 22, 2013
Priority date	Feb 27, 2013
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

Provided are a machining device and a machining method in which machining of higher precision can be performed with a simple configuration. The machining device has an irradiation head ( 16 ) and a controller; and the irradiation head ( 16 ) can be divided into a collimate optical system, a laser revolving unit ( 35 ), and a light collection optical system ( 37 ). The laser revolving unit ( 35 ) has a first prism ( 51 ), a second prism ( 52 ), a first rotation mechanism ( 53 ), and a second rotation mechanism ( 54 ). The controller controls the rotational speeds and the difference in phase angles of the first prism ( 51 ) and the second prism ( 52 ), on the basis of at least the relationship between a heat affected layer of a member to be machined and the revolving speed of the laser.

First claim

The invention claimed is:

1. A machining device that performs a machining process by irradiating a workpiece with a laser beam, the device comprising:
an irradiating head configured to irradiate the workpiece with the laser beam, and having a collimating optical system that collimates the laser beam, a laser beam rotating unit that rotates the laser beam relative to the workpiece, and a converging optical system that converges the laser beam rotated by the laser beam rotating unit to a focal point; and
a controller configured to control the operation of the irradiating head,
wherein the irradiating head is divided into the collimating optical system, the laser beam rotating unit, and the converging optical system,
wherein the laser beam rotating unit has a first prism that refracts the laser beam, a second prism that is disposed to face the first prism and refracts the laser beam output from the first prism, a first rotation mechanism that rotates the first prism, and a second rotation mechanism that rotates the second prism, and
wherein the controller is configured to adjust a difference in rotational speed between the first prism and the second prism and a difference in a phase angle between the first prism and the second prism by controlling the first rotation mechanism and the second rotation mechanism synchronously and relatively in rotation based on a relationship between at least a predetermined thickness allowable to be affected by heat of a heat-affected layer of the workpiece and the rotating speed of the laser beam with which the workpiece is irradiated such that a thickness of the heat affected layer is smaller than the predetermined thickness.

2. The machining device according to claim 1 ,
wherein the irradiating head is configured such that the collimating optical system, the laser beam rotating unit, and the converging optical system are integrally connected to each other.

3. The machining device according to claim 1 ,
wherein the irradiating head has a reflective optical system configured to offset the optical path of the laser beam in the converging optical system relative to the optical path of the laser beam in the laser beam rotating unit, and an index mechanism configured to adjust the angle of the optical path of the laser beam from the reflective optical system to an index angle for the workpiece.

4. The machining device according to claim 3 ,
wherein the index mechanism has an index shaft connected to the reflective optical system, and a hollow shaft motor configured to drive the rotation of the index shaft which is rotatably inserted into the hollow shaft motor.

5. The machining device according to claim 1 ,
wherein the irradiating head has a gap detector for detecting the gap between the focal point of the laser beam and the workpiece.

6. The machining device according to claim 5 ,
wherein the gap detector has an imaging device for capturing an image of a machined portion of the workpiece.

7. The machining device according to claim 1 ,
wherein the irradiating head has a cooling mechanism configured to cool the laser beam rotating unit.

8. The machining device according to claim 1 ,
wherein each of the first prism and the second prism has a polygonal outline.

9. The machining device according to claim 1 ,
wherein an incident surface of the first prism is tilted relative to the optical axis of the laser beam, and an emitting surface of the second prism is tilted relative to the optical axis of the laser beam.

10. The machining device according to claim 1 ,
wherein the irradiating head has an assist gas supply piping therein.

11. The machining device according to claim 1 ,
wherein the irradiating head has a tail-end cutting optical system that cuts the tail-ends of the energy distribution of the laser beam with which the workpiece is irradiated.

12. The machining device according to claim 1 , wherein the machining process includes at least one of cutting, hole piercing, welding, cladding, surface reforming, surface finishing, and laser beam deposition modeling.

13. The machining device according to claim 1 ,
wherein the controller adjusts the difference in the rotational speed between the first prism and the second prism and the difference in the phase angle between the first prism and the second prism by controlling the first rotation mechanism and the second rotation mechanism based on a relationship between at least the predetermined thickness allowable to be affected by heat of the heat-affected layer of the workpiece, the rotating speed of the laser beam with which the workpiece is irradiated, and the rotating radius of the laser beam.

14. A machining method for performing a machining process by irradiating a workpiece with a laser beam using the machining device according to claim 1 , the method comprising:
an output step of outputting the laser beam;
a determination step of determining the difference in the rotational speed between the first prism and the second prism and the difference in the phase angle between the first prism and the second prism based on the relationship between at least the predetermined thickness allowable to be affected by heat of the heat-affected layer of the workpiece, and the rotating speed of the laser beam with which the workpiece is irradiated such that the thickness of the heat affected layer is smaller than the predetermined thickness;
a rotation step of rotating the first rotation mechanism and the second rotation mechanism synchronously and relatively in rotation based on the determined difference in the rotational speed and the determined difference in the phase angle; and an irradiation step of irradiating the workpiece with the laser beam while rotating the laser beam.

15. The machining method according to claim 14 ,
wherein a power of the laser beam is modulated at every rotation of the laser beam relative to the workpiece.

16. The machining method according to claim 14 ,
wherein the workpiece is machined in multiple stages.

17. The machining method according to claim 14 ,
wherein a non-truly circularly shaped hole is pierced in the workpiece.

18. The machining method according to claim 14 ,
wherein the roundness of a hole is detected, the difference in the phase angle between the first prism and the second prism so as to make the irradiation laser beam form a true circular shape corresponding to the detected roundness is calculated, the first prism and the second prism are controlled based on the calculated difference in the phase angle, and thus the roundness of the hole pierced in the workpiece is corrected.

19. The machining method according to claim 14 ,
wherein the gap between the focal point of the laser beam and the workpiece is detected, a relative position between the focal point and the workpiece required to pierce a tapered hole or a straight hole is calculated based on the detected gap, the relative position between the focal point and the workpiece is adjusted to the calculated relative position, the workpiece is irradiated with the laser beam, and thus the tapered or the straight hole is pierced in the workpiece.

20. The machining method according to claim 14 ,
wherein the boundary between different materials of the workpiece is irradiated with a non-circularly-shaped laser beam, and thus an inclined hole is pierced in the workpiece.

21. The machining method according to claim 14 ,
wherein in the determination step, the difference in the rotational speed of the first pris

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Fujita Yoshihito
• Yamashita Tsugumaru
• Goya Saneyuki
• Yamasaki Makoto
• Suzuki Ryu
• Kanaoka Kohei
• Ishide Takashi
• Watanabe Toshiya

Classifications

• B23K26/14

  using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor (B23K26/12 takes precedence) · CPC title

• B23K2203/42

  Operations & Transport · mapped topic

• B23K26/06

  Shaping the laser beam, e.g. by masks or multi-focusing · CPC title

• B23K2203/04

  Operations & Transport · mapped topic

• B23K2203/26

  Operations & Transport · mapped topic