CN114149171A

CN114149171A - Nanosecond laser glass splitting method

Info

Publication number: CN114149171A
Application number: CN202111618105.XA
Authority: CN
Inventors: 胡明; 张国军; 黄禹; 荣佑民; 范新虎
Original assignee: Zhejiang Huagong Guangrun Intelligent Equipment Technology Co ltd; Huazhong University of Science and Technology
Current assignee: Zhejiang Huagong Guangrun Intelligent Equipment Technology Co ltd; Huazhong University of Science and Technology
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2022-03-08

Abstract

The invention relates to the field of material laser processing technology, a nanosecond laser splitting glass method, comprising forming an initial damage surface: focusing a laser beam on a transparent glass workpiece, and generating irreversible crack damage and residual stress inside the transparent glass workpiece through the laser beam, Each pulse of the laser beam produces a single, slender, irreversible initial damage, and the initial damage surface is formed on the transparent glass workpiece by controlling the laser beam along the scanning trajectory; inducing the initial damage expansion: use the carbon dioxide laser beam along the step 1 The scanning trajectory in the middle is scanned again, and the cracks on the initial damage surface are induced by heating to expand under the action of residual stress, and the discontinuous single damage in the initial damage surface gradually expands and connects to form a macroscopic gap, and the transparent glass workpiece is cracked along the macroscopic gap. Slice cutting. The process can reduce the difficulty of the process, reduce the cost of the process, and improve the processing efficiency, which is conducive to expanding the general application of the laser cutting process in the glass cutting industry.

Description

Nanosecond laser glass splitting method

Technical Field

The invention relates to the field of material laser processing technology, in particular to a nanosecond laser glass splitting method.

Background

At present, the glass laser cutting process is widely applied to various glass processing industries, such as electronic display glass, photovoltaic glass, automobile glass and the like. Compared with the traditional mechanical cutting or water jet cutting, the laser cutting has the advantages of high quality, high yield, no water pollution and the like. The laser cutting process is used for glass slicing, and generally, initial damage is generated in glass through focused laser pulses, then, auxiliary means are used for inducing cracks to propagate along damage tracks, and finally, the glass material is cracked.

In order to induce the initial damage inside the high-melting-point and hard and brittle glass material, a picosecond and femtosecond ultrashort pulse laser source is selected, and a light beam is focused to enable the pulse energy density to be higher than a damage threshold value. In chinese patent specification CN106966580B, a femtosecond laser method for cutting glass is disclosed, in which a femtosecond laser is focused on the material to generate stress to cut the glass piece by piece. For the damage depth requirement in the depth direction of thick glass, an ultrashort pulse laser beam is subjected to spatial shaping, such as a bessel beam cutting head with a large focal depth. In the method for picosecond laser cutting of super-thick glass disclosed in Chinese invention patent specification CN111302613A, 1-50ps of laser beam is adopted to be shaped into 0.3-1mm of filament-shaped light spot to realize cutting of thick glass, and a focusing plane needs to be moved for many times for thicker glass.

The damage forms of the femtosecond laser and the picosecond laser cutting of the transparent glass material are all filamentous, the efficiency is improved by improving the damage depth in the depth direction, and the report that the cutting is carried out by forming filamentous damage through the nanosecond laser does not appear at present. Compared with a nanosecond laser source, the ultrafast laser source and the Bessel beam cutting head have the defects of complex equipment and high cost, and the ultrafast laser single pulse energy is low to cause small damage range and limit the improvement of the cutting speed.

Disclosure of Invention

In order to solve the problems, the nanosecond laser glass splitting method provided by the invention is a high-repetition-frequency and high-pulse-energy nanosecond pulse laser slicing and cutting process, so that the process difficulty is reduced, the process cost is reduced, the processing efficiency is improved, and the process is favorable for expanding the general application of the laser cutting process in the glass cutting industry.

In order to achieve the purpose, the invention adopts the technical scheme that:

a nanosecond laser glass splitting method is characterized in that: comprises the following steps of (a) carrying out,

step 1, forming an initial damaged surface: focusing a laser beam on a transparent glass workpiece, generating irreversible crack damage and residual stress in the transparent glass workpiece through the laser beam, generating a single slender irreversible initial damage by each pulse of the laser beam, and controlling the laser beam to form an initial damage surface on the transparent glass workpiece along a scanning track;

step 2, inducing initial damage expansion: and (2) scanning again along the scanning track in the step (1) by using a carbon dioxide laser beam, inducing cracks of the initial damage surface to expand under the action of residual stress by heating, gradually expanding and connecting discontinuous single damages in the initial damage surface to form a macroscopic gap, and cracking the transparent glass workpiece along the macroscopic gap to finish the slicing cutting.

2. The nanosecond laser cleaving glass method of claim 1, wherein: the carbon dioxide laser beam is continuous laser with the power larger than 100W, the negative defocusing amount is 0.1-0.3mm when the beam passes through focusing scanning, and the scanning speed is 1000-3000 mm/s.

3. The nanosecond laser cleaving glass method of claim 1, wherein: the device used by the nanosecond laser glass splitting method comprises a second pulse laser, a beam expander, a reflector, a focusing lens and a moving platform;

a second pulse laser for emitting a laser beam;

a beam expanding lens which is arranged in front of the laser beam transmitting end of the pulse per second laser and is coaxial with the laser beam and is used for expanding the laser beam,

the reflector is arranged in front of the beam expander and used for reflecting the laser beam and enabling the laser beam to enter the focusing lens;

the focusing lens is arranged on a path of the laser beam reflected by the reflector and is used for focusing the laser beam inside the transparent glass workpiece;

and the moving platform bears the transparent glass workpiece and is used for moving the horizontal plane in which the transparent glass workpiece is positioned.

4. The nanosecond laser cleaving glass method of claim 3, wherein: the nanosecond pulse laser has frequency of 40-60kHz, pulse width of 10-20ns, single pulse energy of more than 0.6mJ, and spot mode of TEM₀₀The roundness of a light spot of the Gaussian beam is more than 90%, and the power stability and the pulse energy stability of the laser during working are more than 95%.

5. The nanosecond laser cleaving glass method of claim 3, wherein: the multiple of the beam expander is determined according to the ratio of the diameter of the exit beam of the nanosecond pulse laser to the diameter of the entrance pupil of the focusing lens, the diameter of the entrance pupil of the beam expander is smaller than the diameter of the exit beam of the nanosecond pulse laser, and the maximum bearing peak power of the beam expander is larger than the maximum peak power of the nanosecond pulse laser.

6. The nanosecond laser cleaving glass method of claim 3, wherein: the divergence angle of the beam expander is adjustable.

7. The nanosecond laser cleaving glass method of claim 3, wherein: the reflector is arranged to form an included angle of 45 degrees with the incident direction of the laser beam and is used for reflecting the laser beam after beam expansion by 90 degrees to enter the focusing lens, and the reflector can finely adjust the reflection angle.

8. The nanosecond laser cleaving glass method of claim 3, wherein: the axis of the focusing lens is vertical to the glass workpiece, and the focused laser beam vertically irradiates the glass workpiece and is focused inside the material.

9. The nanosecond laser cleaving glass method of claim 3, wherein: the entrance pupil of the focusing lens is larger than the incident laser beam and larger than 10mm, the effective focal length range of the focusing lens is 60-120mm, and the minimum spot diameter of the focused laser beam is smaller than 10 microns.

10. The nanosecond laser cleaving glass method of claim 3, wherein: the maximum scanning speed of the laser beam driven by the moving platform is 3000 mm/s.

The beneficial effects of the invention are as follows:

the nanosecond laser glass splitting method has the advantages of low equipment cost, simple process operation and high cutting efficiency, and expands the application of glass laser cutting in pursuing high efficiency.

Drawings

FIG. 1 is a three-dimensional schematic diagram of the device for the nanosecond laser glass splitting method.

FIG. 2 is a schematic diagram of the scanning of a carbon dioxide laser beam along an initial damage track in the nanosecond laser cleaving glass process of the invention.

FIG. 3 is a schematic diagram of a glass plate after crack propagation is completed in the nanosecond laser glass splitting method.

FIG. 4 is a dark field photograph of nanosecond laser pulses induced in glass to produce filamentary damage and crack propagation in glass according to the nanosecond laser cleaving method of the invention.

The reference signs are: the device comprises a 1-nanosecond pulse laser, a 2-beam expander, a 3-reflector, a 4-focusing lens, a 6-laser beam, a 7-transparent glass workpiece and an 8-carbon dioxide laser beam.

Detailed Description

In order to make the purpose, technical solution and advantages of the present technical solution more clear, the present technical solution is further described in detail below with reference to specific embodiments. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present teachings.

As shown in fig. 1, a three-dimensional schematic diagram of initial damage of a nanosecond pulse laser built in a transparent glass workpiece in step 1 of an embodiment of the invention is shown, main equipment of the nanosecond pulse laser slicing and cutting process for transparent glass according to the invention is composed of a nanosecond pulse laser 1, a beam expander 2, a reflector 3, a focusing lens 4 and a moving platform, a laser beam 6 emitted by the nanosecond pulse laser 1 is expanded by the beam expander 2 and reflected by the reflector 3 to enter the focusing lens 4, and the focusing lens 4 focuses the laser beam 6 inside the transparent glass workpiece 7.

Specifically, the frequency of the nanosecond pulse laser 1 is 40-60kHz, the pulse width is 10-20ns, the single pulse energy is more than 0.6mJ, and the light spot mode is TEM₀₀The roundness of a light spot of the Gaussian beam is more than 90%, and the power stability and the pulse energy stability of the laser during working are more than 95%.

The beam expander 2 is installed at the front end of the nanosecond pulse laser 1 and is coaxial with the laser beam 6, the multiple is determined according to the ratio of the diameter of the exit beam of the nanosecond pulse laser 1 to the diameter of the entrance pupil of the focusing lens 4, the diameter of the entrance pupil of the beam expander 2 is smaller than the diameter of the exit beam of the nanosecond pulse laser 1, the maximum borne peak power is larger than the maximum peak power of the nanosecond pulse laser 1, and the divergence angle of the beam expander 2 is adjustable.

The mirror 3 is mounted at 45 ° to the laser beam in order to reflect the expanded laser beam 6 through 90 ° into the focusing lens 4, the mirror 4 allowing fine adjustment of the reflection angle. The axis of the focusing lens 4 is vertical to the glass workpiece 7, the focused laser beam 6 vertically irradiates the glass workpiece 7 and is focused inside the material, the entrance pupil of the focusing lens 4 is larger than the incident laser beam 6 and is larger than 10mm, the effective focal length range is 60-120mm, and the minimum spot diameter of the focused laser beam 6 is smaller than 10 microns.

The focused laser beam 6 irradiates the transparent glass workpiece 7 and generates irreversible crack damage and residual stress in the transparent glass workpiece, each pulse generates a single long and thin irreversible initial damage through the nanosecond pulse laser 1 and other devices, an initial damage surface can be formed along a scanning track under the driving of the moving platform 5, and the maximum scanning speed can reach 3000 mm/s.

Referring to fig. 2 showing step 2 of an embodiment of the present invention, the carbon dioxide laser heating induces the propagation of the initial damage, and according to the embodiment of the present invention, step 1 forms the initial damage surface in the transparent glass workpiece 7 by the focused nanosecond laser beam 6, the carbon dioxide laser beam 8 is scanned again along the scanning track of step 1, and the crack of the initial damage surface is induced by heating to propagate under the action of the residual stress. The carbon dioxide laser beam 8 is continuous laser with the power more than 100W, the beam is focused, the negative defocusing amount is 0.1-0.3mm during scanning, and the scanning speed is 1000-3000 mm/s. As the carbon dioxide laser beam 8 is scanned, discrete individual lesions in the initial lesion surface gradually expand and join to form macroscopic gaps.

As shown in fig. 3, after the initial damage is completely expanded and sliced, the initial damage surface is expanded under the thermal induction of the scanning of the carbon dioxide laser beam 8 to form a macro gap according to step 2 of the embodiment of the present invention, after the scanning of the carbon dioxide laser beam 8 is completed, the macro gap is completely expanded, and the transparent glass workpiece 7 is cracked along the macro gap to complete the slicing and cutting. And completing the nanosecond pulse laser slicing cutting process embodiment of the transparent glass.

As shown in FIG. 4, the damage dark field image formed by rapidly scanning nanosecond laser pulses in transparent glass is formed, each pulse forms a filament along the propagation direction of a light beam, a plurality of pulse damages are arranged in parallel, and the stress generated by the laser pulses can cause transverse-expansion cracks around the filament-shaped damages to form splitting. And (3) inducing the cracks to further expand by the carbon dioxide laser beam to form macroscopic fracture, and realizing the slicing cutting of the glass after the scanning is finished.

The foregoing is only a preferred embodiment of the present invention, and many variations in the specific embodiments and applications of the invention may be made by those skilled in the art without departing from the spirit of the invention, which falls within the scope of the claims of this patent.

Claims

1. a nanosecond laser splitting glass method, is characterized in that: comprise the steps,

Step 1. Form the initial damage surface: focus the laser beam on the transparent glass workpiece, and generate irreversible crack damage and residual stress inside the transparent glass workpiece through the laser beam. Each pulse of the laser beam will generate a single slender irreversible initial For damage, the initial damage surface is formed on the transparent glass workpiece by controlling the laser beam along the scanning trajectory;

Step 2. Induce the initial damage expansion: use the carbon dioxide laser beam to scan again along the scanning trajectory in step 1, and induce the crack on the initial damage surface to expand under the action of residual stress by heating, and the discontinuous single damage in the initial damage surface gradually expands and connects. , forming a macro gap, and the transparent glass workpiece is cracked along the macro gap to complete the slice cutting.

2. The method for splitting glass by nanosecond laser according to claim 1, wherein the carbon dioxide laser beam is a continuous laser, the power is greater than 100W, the negative defocus amount is 0.1-0.3mm when the beam is scanned by focusing, and the scanning speed is 0.1-0.3 mm. 1000-3000mm/s.

3. nanosecond laser splitting glass method according to claim 1, is characterized in that: the equipment that described nanosecond laser splitting glass method uses comprises second pulse laser, beam expander, reflecting mirror, focusing lens and moving platform ;

Second pulse laser, for emitting laser beam;

The beam expander is arranged in front of the laser beam emission end of the second pulse laser and is coaxial with the laser beam, used to expand the laser beam,

A reflector, arranged in front of the beam expander, is used to reflect the laser beam and make the laser beam enter the focusing lens;

The focusing lens is arranged on the path of the laser beam reflected by the mirror, and is used to focus the laser beam on the inside of the transparent glass workpiece;

The moving platform carries the transparent glass workpiece and is used to move the transparent glass workpiece in the horizontal plane.

4. The method for splitting glass by nanosecond laser according to claim 3, wherein the frequency of the nanosecond pulse laser is 40-60kHz, the pulse width is 10-20ns, the single pulse energy is greater than 0.6mJ, and the spot mode is It is a TEM ₀₀ Gaussian beam, the circularity of the spot is greater than 90%, and the power stability and pulse energy stability of the laser are greater than 95%.

5. nanosecond laser splitting glass method according to claim 3, is characterized in that: described beam expander multiple is determined according to the ratio of the exit beam diameter of nanosecond pulse laser and the entrance pupil diameter of focusing lens, beam expander The diameter of the entrance pupil is smaller than the exit beam diameter of the nanosecond pulsed laser, and the maximum peak power of the beam expander is greater than the maximum peak power of the nanosecond pulsed laser.

6 . The method for splitting glass by nanosecond laser according to claim 3 , wherein the divergence angle of the beam expander is adjustable. 7 .

7. nanosecond laser splitting glass method according to claim 3, is characterized in that: described mirror is installed to form 45 ° angle with the incident direction of laser beam, is used to reflect 90 ° of laser beam through beam expanding to enter Focusing lens, reflector can fine-tune the reflection angle.

8 . The method for splitting glass by nanosecond laser according to claim 3 , wherein the axis of the focusing lens is perpendicular to the glass workpiece, and the focused laser beam irradiates the glass workpiece vertically and focuses on the inside of the material. 9 .

9. The method for splitting glass by nanosecond laser according to claim 3, wherein the entrance pupil of the focusing lens is larger than the incident laser beam and larger than 10mm, and the effective focal length range of the focusing lens is 60-120mm. The minimum spot diameter of the laser beam is less than 10 microns.

10 . The method for splitting glass by nanosecond laser according to claim 3 , wherein the maximum scanning speed that the moving platform drives the laser beam to reach is 3000 mm/s. 11 .