Laser processing apparatus and laser processing method

Patent metadata

Field	Value
Publication number	US-11504803-B2
Application number	US-201916256031-A
Country	US
Kind code	B2
Filing date	Jan 24, 2019
Priority date	Jan 30, 2018
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

A laser processing apparatus includes a light source which outputs a laser light, and a waveform control unit which controls a pulse waveform of the laser light irradiating the workpiece, in which the pulse waveform of the laser light controlled by the waveform control unit includes a main pulse and a foot pulse temporally preceding the main pulse, and a peak intensity of the foot pulse is smaller than a peak intensity of the main pulse, and a peak position of the main pulse is positioned in a retention time period of plasma generated due to an incidence of the foot pulse on the workpiece.

First claim

What is claimed is:

1. A laser processing apparatus which performs laser peening by irradiating a workpiece with a laser light, the laser processing apparatus comprising:
a light source which outputs the laser light; and
a waveform controller which controls a pulse waveform of the laser light irradiating the workpiece, wherein
the pulse waveform of the laser light controlled by the waveform controller includes a main pulse incident on the workpiece that plastically deforms the workpiece and a foot pulse temporally preceding the main pulse that generates plasma on a surface of the workpiece, and
a peak intensity of the foot pulse is smaller than a peak intensity of the main pulse, and a peak position of the main pulse is positioned in a retention time period of the plasma generated due to an incidence of the foot pulse on the workpiece.

2. The laser processing apparatus according to claim 1 , wherein the pulse waveform of the laser light includes a single main pulse and a single foot pulse.

3. The laser processing apparatus according to claim 1 , wherein the peak intensity of the foot pulse is 2% or more and less than 100%, when the peak intensity of the main pulse is 100%.

4. The laser processing apparatus according to claim 1 , wherein a time interval between a peak position of the foot pulse and the peak position of the main pulse is 1 ns or more and 20 ns or less.

5. A laser processing method which performs laser peening by irradiating a workpiece with a laser light, the laser processing method comprising:
a waveform control step of controlling a pulse waveform of the laser light irradiating the workpiece; and
an irradiation step of irradiating the workpiece with the laser light whose pulse waveform is controlled in the waveform control step, wherein, in the waveform control step,
a main pulse incident on the workpiece to plastically deform the workpiece and a foot pulse temporally preceding the main pulse to generate plasma on a surface of the workpiece are formed into the pulse waveform of the laser light in the waveform control step, and
a peak intensity of the foot pulse is made smaller than a peak intensity of the main pulse, and a peak position of the main pulse is made to be positioned in a retention time period of the plasma generated due to an incidence of the foot pulse on the workpiece.

6. The laser processing method according to claim 5 , wherein a single main pulse and a single foot pulse are formed into the pulse waveform of the laser light in the waveform control step.

7. The laser processing method according to claim 5 , wherein the peak intensity of the foot pulse is set to 2% or more and less than 100%, when the peak intensity of the main pulse is 100% in the waveform control step.

8. The laser processing method according to claim 5 , wherein a time interval between a peak position of the foot pulse and the peak position of the main pulse is set to 1 ns or more and 20 ns or less in the waveform control step.

9. The laser processing method according to claim 5 , wherein irradiation of a surface of the workpiece with the laser light is performed in a state in which a protective film is formed thereon in the irradiation step.

10. The laser processing method according to claim 5 , wherein irradiation of the workpiece with the laser light is performed in a state in which a plasma confinement film is formed thereon in the irradiation step.

Assignees

• Hamamatsu Photonics Kk

Inventors

• Mizuta Yoshio
• Kurita Takashi
• Watari Takeshi
• Kabeya Yuki
• Kurita Norio
• Kawashima Toshiyuki

Classifications

• B23K26/0622 Primary

  by shaping pulses · CPC title

• B23K26/356

  by shock processing · CPC title

• C21D10/005

  by laser shock processing · CPC title

• B23K26/009

  using a non-absorbing, e.g. transparent, reflective or refractive, layer on the workpiece (using a mask on the workpiece B23K26/0661) · CPC title