US 5,609,284 A · Method of splitting non-metallic materials

Abstract

A method of cutting non-metallic materials, specifically glass, resides in the heating of the material by an incident beam of radiation being effected to a temperature short of its softening point, with the rate of relative displacement of the beam and of the material, and the region of the heated zone which is locally cooled being selected to form a blind crack in the material. The method provides for increasing substantially the cutting speed and accuracy, and also for controlling the depth, shape and angle of the cut face formed by the crack. The method can be employed in the automotive industry for making glass windows and mirrors, in the electronics industry for making precision backings and substrates for LED indicator panels and masks, magnetic and optomagnetic disks, in watch-making for making protective glasses, in the aircraft and space industry for making structural optics components, in construction and architecture for dimensional pattern-cutting of glass, including its integration in the glass manufacturing technology, and also in other fields of production and technologies where precision of non-metallic materials are made.

Claims15

Dependent claims

A method of separating two portions of a body of brittle non-metallic material from each other including the step of forming a blind crack extending into the body to a given depth from a surface thereof, and in an intended direction along the surface, by effecting relative movement at a rate of relative displacement between the body and an elliptical target area on the surface thereof, said target area having a transverse minor axis and a longitudinal major axis, and being formed by directing an elliptical beam of coherent radiation towards the surface, the elliptical beam incident on the surface forming a spot, the spot having a major axis aligned substantially along the intended direction of the crack, and controlling the energy of the beam so that the beam heats the surface to a temperature below the softening point of the material while simultaneously directing a stream of fluid coolant at an area of the heated surface which constitutes a cooling zone in the intended direction, the fluid coolant being displaced behind the heated target area by a chosen distance, wherein the rate of relative displacement between the beam and the body satisfies the equation:

V=ka(b+L)/.delta.
where
V is the rate of relative displacement of the beam spot and the body;
k is a proportionality factor dependent on the thermophysical properties of the material of the body and a beam power density of the beam;
a is the length of said transverse minor axis;
b is the length of said longitudinal major axis;
L is the distance from the rear edge of the heat beam spot to the from edge of the cooling zone;
and
.delta. is the depth of the blind crack.

6 more elements

A method of separating two portions of a body of brittle non-metallic material from each other along a curvilinear outline of relatively small curvature radii including the step of forming a blind crack extending into the body to a given depth from a surface thereof, and in an intended direction along the surface, by effecting relative movement at a rate of relative displacement between the body and an elliptical target area on the surface thereof, said target area having a transverse minor axis and a longitudinal major axis, and being formed by directing an elliptical beam of coherent radiation towards the surface, the elliptical beam incident on the surface forming a spot, the spot having a major axis aligned substantially along the intended direction of the crack, and controlling the energy of the beam so that the beam heats the surface to a temperature below the softening point of the material while simultaneously directing a stream of fluid coolant at an area of the heated surface which constitutes a cooling zone in the intended direction, the fluid coolant being displaced behind the heated target area by a chosen distance, wherein the rate of relative displacement between the beam and the body satisfies the equation:

V=ka(b+L)/.delta.
where
V is the rate of relative displacement of the beam spot and the body;
k is a proportionality factor dependent on the thermophysical properties of the material of the body and a beam power density of the beam;
a is the length of said transverse minor axis;
b is the length of said longitudinal major axis;
L is the distance from the rear edge of the heat beam spot to the front edge of the cooling zone;
and
.delta. is the depth of the blind crack;
and including the further step of post heating the body, after the blind crack has been formed, along the line of the crack and to an extent sufficient to cause the depth of the crack to increase further, the post heating step being effected by means of a second beam of radiation impinging on the surface and moved relatively to the body along a path coincident with, or parallel to, the crack, yet offset from the centre of a curvilinear outline when cutting along the curvilinear outline.

7 more elements

A method of separating two portions of a body of brittle non-metallic material from each other including the step of forming a blind crack along a closed curve extending into the body to a given depth from a surface thereof, and in an intended direction along the surface, by effecting relative movement at a rate of relative displacement between the body and an elliptical target area on the surface thereof, said target area having a transverse minor axis and a longitudinal major axis, and being formed by directing an elliptical beam of coherent radiation towards the surface, the elliptical beam incident on the surface forming a spot, the spot having a major axis aligned substantially along the intended direction of the crack, and controlling the energy of the beam so that the beam heats the surface to a temperature below the softening point of the material while simultaneously directing a stream of fluid coolant at an area of the heated surface which constitutes a cooling zone in the intended direction, the fluid coolant being displaced behind the heated target area by a chosen distance, wherein the rate of relative displacement between the beam and the body satisfies the equation:

V=ka(b+L)/.delta.
where
V is the rate of relative displacement of the beam spot and the body;
k is a proportionality factor dependent on the thermophysical properties of the material of the body and a beam power density of the beam;
a is the length of said transverse minor axis;
b is the length of said longitudinal major axis;
L is the distance from the rear edge of the heat beam spot to the front edge of the cooling zone;
and
.delta. is the depth of the blind crack;
and including the further step of first scoring the surface of the body along an incremental part of the desired crack to form a score, with the depth of the score being different at opposite ends thereof, and in which the beam of radiation is initially directed at that part of the score which is of greater depth.

7 more elements

Dependencies are inferred from the claim text.

Method of splitting non-metallic materials

Life of this patent

Method of splitting non-metallic materials

Life of this patent

Abstract

Claims15