EA004167B1 - Method for glass cutting - Google Patents

Abstract

1. A method for cutting glass by a laser beam, the glass is opaque for the beam, the method comprising treating the separation line by a concentrated laser beam with a subsequent applying a heat source on the separation line, characterized in that a defocused laser beam is used as the heat source. 2. The method according to claim 1, characterized in that at the initial step of treating the glass surface along the separation line by the concentrated beam with a temperature higher than the initial glass softening temperature, a concave or convex zone relative to the glass surface is created close by its width to the laser beam diameter with residual tensile stresses in the near-the-surface layers. 3. The method according to claim 2, characterized by further treating the glass by a defocused laser beam at a glass temperature lower the initial glass softening temperature thus creating additional tensile stresses, which exceed the summed glass strength parameters and cause forming cracks in glass.

Description

The alleged invention relates to a method for cutting glass with a laser beam and can be used in glass, electronic, aviation and other sectors of the economy.

A known method of cutting glass by heating the cut line with a laser beam and splitting the glass plates along the cut line (1), moreover, the cutting line is additionally heated by repeatedly passing the laser beam reflected from the substrate through the plate.

The disadvantage of this method is the inability to split large sizes of sheet glass along a given curved line of separation, since the split using mirrors can only be carried out in straight lines.

The closest prototype of the invention is a method for cutting hollow glassware (2), in which the glassware is rotated and the cut line is irradiated with a laser beam of a certain power focused on the surface of the product, creating glass heating along the line of the required cut. When this heating is carried out at different speeds, starting from a small number of revolutions Ч ₁ , providing heating at the focal point to the evaporation temperature T _isp , forming a groove along the dividing line. Then increase the number of revolutions to Ch ₂ , ensuring the accumulation of heat in the groove zone, and when a certain temperature is reached, T _load = T _isp . thermal stresses occur, leading to thermal splitting along the dividing line.

The disadvantage of this method is the limited use (for cutting glass tubes, ampoules), in particular, it cannot be used for cutting sheet glass, because in this case, due to the practical limitation of the speed of the mutual movement of the beam and glass, it is not possible to obtain an increase in heat after the beam returns to the point where the heating begins.

The essence of the proposed method of cutting glass is that upon initial exposure to a focused beam create a temperature in the glass above the softening temperature and cause a strip to appear in the section concave or convex relative to the surface of the product, close in width to the diameter of the laser beam and having residual tensile stresses in the near-surface layers. With the subsequent exposure to a defocused beam at a glass temperature below the temperature of the onset of softening, additional tensile stresses are created that in total exceed the strength parameters of the glass and cause cracking.

Below the proposed method is illustrated by specific examples.

Example 1

3 mm thick float glass was used as sheet glass. Glass cutting size of 300 mm was used CO ₂ laser IGL-709 60W. The relative velocity of the glass relative to the beam was 2 m / min. The diameter of the laser beam was 2.5 + 3.0 mm with primary focused exposure. In this case, heating lines with a width close to the size of the diameter of the laser beam were formed at a temperature of 770 ° С on the glass surface in the zone of influence, i.e. 2.5 + 3.0mm. Then, after 5-6 s, a secondary exposure was performed with a defocused beam with a diameter of 10 mm at the same speed. The temperature on the glass surface did not exceed 450-500 ° C. A through crack formed at the beginning of the secondary action followed the passage of the laser beam.

Example 2

The same method was used when cutting sheet glass with a thickness of 1.2 mm. The speed of movement of the glass and the beam relative to each other during the initial exposure was 5 m / min; when exposed to a focused beam with a diameter of 3-4 mm after 2-3 seconds, the speed was maintained.

The achieved positive effect is that in this way it is possible to separate very thin (0.2-0.5 mm) sheet glass.

Sources of information taken into account:

1. Auth. testimonial. USSR No. 690809, С03В 33/09, 1979

2. Russian Patent No. 2015118, С03В 33/00, 1994.

Claims (3)

CLAIM 1. The method of cutting glass by exposing the surface to a laser beam, the glass being opaque to the beam, including an impact along the separation line focused on the surface of the glass product with a laser beam followed by a heat source along the separation line, characterized in that the defocused source is used laser ray. 2. The method according to claim 1, characterized in that, upon initial exposure, a beam focused on the glass surface along a separation line at a temperature above the softening start temperature creates in the cross section a concave or convex strip relative to the product surfaces that is close in width to the diameter of the laser beam with residual tensile stresses in the near-surface layers. 3. The method according to claim 1, characterized in that upon subsequent exposure to a defocused laser beam at a glass temperature below the softening start temperature, additional tensile stresses are created, which total exceed the glass strength parameters and cause the formation of cracks.