CN112645580A

CN112645580A - Glass cutting method and glass material

Info

Publication number: CN112645580A
Application number: CN202011077241.8A
Authority: CN
Inventors: 堤康; 池西干男
Original assignee: Hoya Corp
Current assignee: Hoya Corp
Priority date: 2019-10-10
Filing date: 2020-10-10
Publication date: 2021-04-13
Also published as: JP7284682B2; TW202124305A; JP2021062982A

Abstract

The invention provides a method for cutting glass and a glass material manufactured by the method, wherein the method for cutting glass has no complicated device and can obtain beautiful cut surfaces efficiently and accurately. A method of cleaving glass, comprising: bringing an ultrasonic vibration blade of an ultrasonic cutting machine into contact with a portion of glass to be cut; a step of subjecting the ultrasonic vibration blade to ultrasonic vibration; and cutting the glass into a notch while linearly generating frictional heat by the ultrasonic wave.

Description

Glass cutting method and glass material

Technical Field

The present invention relates to a method for cutting glass and a glass material cut by the method.

Background

Conventionally, as a method of cutting a brittle material such as glass into a predetermined size, the following methods are known: 1) a method of physically cutting glass using a cutting blade in which abrasive grains harder than glass are embedded, for example, a round blade in which diamond abrasive grains are embedded; 2) a part of the glass is cracked, and the crack is spread by applying pressure, that is, the glass is cut (cleaved) by the fact that the stress generated in the glass is larger than the bending strength of the glass.

As a method of cutting glass by the latter cutting method, cutting by manual cutting is generally used. The manual cutting is as follows: first, a glass is pressed against a disk-shaped blade rotated by a motor or the like, a notch having a depth of less than about 3mm is physically formed in the glass, and then the glass is subjected to pressure or heating or cooling in the vicinity of the notch, thereby generating mechanical or thermal stress in the glass and cutting the glass.

In the case of manual cutting or the like, it is preferable that the direction of the crack coincides with a predetermined direction. However, since the glass and the disk-shaped blade are in point contact, the thermal stress acting on the crack has a concentric distribution from the contact point of the glass and the blade, and the concentric distribution acts on the crack generated at the contact point of the glass and the blade, and therefore, depending on the shape of the glass sample, the crack cannot be propagated in a predetermined direction, and the glass cannot be cut in an accurate size. In particular, in the case of thick glass, it is difficult to apply uniform mechanical stress to the glass, which causes cracks to propagate uniformly in a desired cutting direction, and therefore, there is a problem that the cut surface becomes a curved surface and it is difficult to cut the glass neatly.

As a method for solving such a problem, for example, patent document 1 discloses a method of "cutting by applying a uniform lateral pressure to a side surface of a glass to be cut and utilizing an internal stress generated in the glass". This method describes that the method is suitable for a material having a high unit price because no chips are generated and the loss is small.

Patent document 2 discloses a "method of heating a brittle material along a cutting line, cooling the material along the cutting line, causing a crack to be generated in the surface of the brittle material by a thermal stress, and breaking the material along the crack, and cooling a stress inflection point or its vicinity where a compressive stress of the brittle material generated by expansion due to the heating changes to a tensile stress, on the cutting line of the brittle material, thereby causing a crack to be generated in the surface of the brittle material". This method describes the advantages of more efficient work and obtaining a beautiful cut surface.

However, in the method using lateral pressure disclosed in patent document 1, when the method is used for a glass having a large number of microcracks on the surface, such as a file or a heated cutter, there is a possibility that the internal cracks are not located at one place and it is difficult to accurately cut the glass at a target position. In the laser beam cutting method disclosed in patent document 2, since the laser beam irradiation method and the cooling method are repeated along the cutting line, the apparatus becomes complicated, and since the microscopic heat distribution on the glass surface is concentric from the irradiation point of the laser beam, cracks do not necessarily extend in a predetermined direction (depth direction), and in particular, thick glass is difficult to cut.

Further, there are methods such as: the glass is placed on a linear heating line after heating, and the glass is cleaved by causing a crack to develop in the end face of the glass and extending the crack in the direction of a thermal stress portion developed in the heating line. In this method, although a linear thermal distribution is applied to the glass, the physical stress applied to the glass is only a thermal stress caused by thermal expansion, and therefore the possibility of cutting and the accuracy of cutting strongly depend on the shape of the glass of the base material, and the position where cutting is possible is limited to the central portion of the glass. As a result, the method is only suitable for halving a relatively large plate-shaped glass, and is not suitable for manufacturing a small-sized cut workpiece having an arbitrary shape.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 61-266323

Patent document 2: japanese laid-open patent publication No. 2004-155159

Disclosure of Invention

Problems to be solved by the invention

The invention provides a method for cutting glass, which can efficiently and highly accurately obtain beautiful cut surfaces without requiring a complicated apparatus, and a glass material obtained by the cutting method.

Means for solving the problems

The present inventors have found that when an ultrasonic cutter is used, the state of a cleaved surface is particularly excellent as compared with conventional manual cutting, and have completed the present invention. The present invention includes the following.

[1] A method of cleaving glass, comprising: bringing an ultrasonic vibration blade of an ultrasonic cutting machine into contact with a portion of glass to be cut; a step of subjecting the ultrasonic vibration blade to ultrasonic vibration; and cutting the glass into a notch while linearly generating frictional heat by the ultrasonic wave.

[2] A method for cutting glass according to claim 1, wherein the frequency of the ultrasonic vibration is 5kHz or more and 50kHz or less.

[3] A method for cutting glass according to claim 1 or 2, wherein the amplitude of the ultrasonic vibration is 5 μm or more and 40 μm or less.

[4] A glass material obtained by the cleaving method of claim 1.

[5] A severance method according to claim 4 wherein the waviness of the severed face of the glass material is 100 or less.

[6] A method of manufacturing a glass material, comprising: bringing an ultrasonic vibration blade of an ultrasonic cutting machine into contact with a portion of glass to be cut; a step of subjecting the ultrasonic vibration blade to ultrasonic vibration; and cutting the glass into a notch while linearly generating frictional heat by the ultrasonic wave.

[7] A glass material having at least a surface with waviness of 100 or less and a surface roughness Ra of 500 [ mu ] m or less.

[8] The glass material according to [7], wherein the face is a cut face.

[9] The glass material according to [7] or [8], wherein a content ratio of boron and/or alkali components and/or fluorine in the surface is higher than a content ratio of these elements which are not contained in a glass surface of the surface in the glass material.

[10] The glass material according to [7] or [8], wherein a content ratio of boron and/or alkali components and/or fluorine in the surface is higher by 5% or more than a content ratio of these elements not contained in a glass surface of the surface in the glass material.

Effects of the invention

In the present invention, the ultrasonic vibration blade of the ultrasonic cutting machine ultrasonically vibrates a portion where glass is to be cut, and thus the glass and the ultrasonic vibration blade can be brought into contact with each other in a linear uniform manner, not in point contact with a circular blade such as a conventional diamond cutter. This also has a feature that the heat distribution generated in the glass by the cutting edge is linear. As a result, the ultrasonic cutter cuts the glass while heating the glass linearly, and hence the waviness is small, and a beautiful cut surface can be obtained. If the waviness of the cut surface is small, the polishing amount can be suppressed in the subsequent polishing step, and the amount of glass cullet can be reduced.

Drawings

Fig. 1 is a perspective view showing a case where a notch is cut in a glass G by an ultrasonic cutting machine used in the present invention.

Fig. 2 is a schematic diagram showing a heat distribution when the ultrasonic cutting machine of the present invention is brought into contact.

Fig. 3 is a perspective view showing a state in which a notch is cut in the conventional cleaving method.

Fig. 4 is a schematic diagram showing a heat distribution when a notch is cut in the conventional cleaving method.

Fig. 5 is a diagram showing the formula for calculating the cleavage difficulty N of the glass material and the meanings of variables in the formula.

FIG. 6 is a side view showing the measurement of waviness X of a glass material having a cut surface.

Fig. 7 is a graph showing the relationship between the ease of cleaving N and the waviness X.

Description of the reference numerals

G glass

The desired parts G1 and G2 are cut

1 ultrasonic cutting machine

11 ultrasonic vibration blade

11a arrows indicating the vibration directions of the ultrasonic vibration blades

2 Manual cutting

21 disc-shaped blade

22 motor

3. 4 heating part

Clearance distance between D cut section and simple straight surface

Thickness of T

Width W

Length of L

Detailed Description

[ glass cutting method ]

Hereinafter, a glass cutting method by an ultrasonic cutting machine will be described with reference to the drawings. Fig. 1 is a perspective view showing glass cutting by an ultrasonic cutting machine. Fig. 2 is a schematic diagram showing a heat distribution when the ultrasonic cutting machine 1 cuts the workpiece. The ultrasonic vibration blade 11 of the ultrasonic cutting machine 1 is brought into contact with a portion G1 to be cut of the glass G to be cut, and ultrasonic vibration is applied to the ultrasonic vibration blade 11 in the direction of an arrow 11a indicating the vibration direction. The ultrasonic vibration blade 11 is brought into contact with the glass G by ultrasonic vibration, and generates linear frictional heat at the portion G1 to be cut, and generates linear cuts. Thus, since the thermal stress and the linear mechanical stress linearly occur in the direction in which the glass is to be cut, the glass can be cut without substantially applying any other pressure to the glass base material.

When the ultrasonic vibrating blade of the ultrasonic cutting machine is the ultrasonic vibrating blade 11 such as the cutting machine shown in fig. 1, the heat generated by the ultrasonic vibration is distributed linearly around the linear heating portion (fig. 2). Since the glass is cut by generating mechanical stress through the linear notch while generating frictional heat in a linear shape, and by generating and propagating cracks at a position where the ultrasonic vibration blade contacts, the cut surface at the time of cutting becomes a clean surface, that is, a smooth surface with a small waviness. The definition of waviness will be described later.

The depth of the crack generated by the ultrasonic cutter 1 is about 0.2 to 2mm, preferably 0.2 to 1mm or less, depending on the thickness of the glass. This depth of cut is shallower than the depth of cut in conventional manual cutting. The time required for cutting is not particularly limited, but since the glass is cut by the above-described mechanism, it is not preferable to apply only the mechanical stress before sufficient frictional heat is generated, and on the contrary, it is not preferable to apply only the mechanical stress after the frictional heat is diffused to the outside of the cut portion. From such a viewpoint, the time required for cutting the crack can be appropriately changed depending on the hardness and size of the glass. The lower limit of the cutting time when actually cutting the glass is set to 0.1 sec/mm or more, preferably 0.3 sec/mm, more preferably 0.5 sec/mm, and still more preferably about 0.1 sec/mm. The upper limit of the cutting time is preferably about 15 seconds/mm, preferably about 10 seconds/mm, and more preferably about 5 seconds/mm. Conversely, if the cutting time exceeds 30 seconds/mm or 60 seconds/mm, the frictional heat diffuses to the periphery, and the mechanical stress decreases, which is not preferable.

The size of the glass used for cleaving is not particularly limited, but in the case of a rectangular glass, the glass may be one having a height of 1 to 40mm, a width of 1 to 40mm, and a length of, for example, 10mm or more. The present invention is not limited to a rectangular parallelepiped, and can be applied to cylindrical glass, triangular cylindrical glass, and the like. (the difficulty of cleaving in this case can be distinguished from the difficulty of cleaving described later.)

(ultrasonic cutting machine)

The ultrasonic cutting machine used in the present invention may be a commercially available one, and for example, an ultrasonic small-sized cutting machine USW-334 manufactured by PolyElectron Ltd.

The lower limit of the ultrasonic frequency of the ultrasonic cutter is preferably 5kHz or more, more preferably 10kHz or more, and further preferably 15kH or more, and the upper limit is preferably 50kHz or less, more preferably 45kHz or less, and further preferably 40kHz or less.

The lower limit of the amplitude of the ultrasonic vibration blade is preferably 5 μm or more, more preferably 10 μm or more, and the upper limit is preferably 40 μm or less, more preferably 30 μm or less.

The output of the ultrasonic vibration blade is not particularly limited, but for example, the range from 5W to 500W may be changed to 5W, 10W, 20W, 30W, 40W, 50W, 60W, 70W, 80W, 90W, 100W, 150W, … … as the lower limit of the output and 30W, 60W, 80W, 100W, 150W, 200W, 300W, 400W, 500W as the upper limit, and the output may be changed as appropriate depending on the hardness of the glass, the width at the time of cleaving, and the degree of difficulty of cleaving, which will be described later. The output range may be, for example, 10W to 30W, 20W to 60W, 40W to 100W, 100W to 300W, 200W to 400W, or the like. When the hardness of the glass is high, the frictional heat in the shearing direction of the glass can be increased by increasing the output, and the glass can be cut. Therefore, when the hardness of the glass is high, the hardness varies depending on the difficulty of cleaving, but the glass can be cleaved by setting the output to 80W or more, for example. However, if the output is made too large, it is difficult to heat the glass unless the contact between the glass and the blade is made uniform, and therefore it is not necessary to increase the output to an output at which the glass can be cut or more.

The size of the ultrasonic vibration blade is not particularly limited, and the thickness of the blade is preferably 0.1mm or more and 1.0mm or less, and more preferably 0.3mm or more and 0.8mm or less.

The entire length of the ultrasonic vibration blade may be appropriately selected according to the size of the glass to be cut, and for example, a length of 20mm to 100mm may be used.

The material is not particularly limited as long as it has a predetermined hardness such as ceramics and metals, and steel materials such as SKH51 can be used.

As shown in fig. 1, the ultrasonic vibration blade of the ultrasonic cutter is a thin plate-like blade like the shape of the blade of the cutter for cutting paper, but is not limited to this ultrasonic vibration blade, and for example, a point-contact pen-like ultrasonic vibration blade may be used. In this case, by cutting the glass so as to scribe a line in a state of contact, a linear crack is generated, and a notch having a shape close to the same shape as that of the ultrasonic vibration blade can be produced.

The vibration direction of the ultrasonic wave is the direction of vibration in the direction of the axis of the shank of the ultrasonic cutter (direction 11a in fig. 1).

On the other hand, as shown in fig. 3, the conventional manual cutting cuts the glass G by bringing the disc-shaped blade 21 into contact with the glass G to physically form a notch having a depth of about 3 mm. However, in such a device, since the contacts are concentrated at one point and there is a distribution of thermal stress in a direction other than the intended cutting direction, it is difficult to cut the contact neatly if the cutting difficulty described below is high.

[ difficulty of cleaving ]

The cleaving method of the present invention has a feature that even when the cleaving difficulty is high, the cleaving can be performed in good order. The degree of difficulty in breaking the glass was calculated by the formula shown in fig. 5. The higher the glass is cut, the more difficult it is. In the formula of the degree of difficulty of cleaving, T is the thickness, W is the width, and L is the length. The smaller the values of T/L and W/L in the formula, the easier the cleavage, and preferably 1 or less, respectively. In addition, the smaller the thickness T, the easier the cleaving.

Regarding the difficulty of cleaving, in cleaving by conventional manual cutting, if the difficulty of cleaving exceeds 2, cleaving becomes difficult, and even if cleaving is possible, the waviness described below becomes large. Therefore, the cutting by the conventional manual cutting is generally applied to glass having a height of 5 to 20mm and a width of 5 to 20 mm. In contrast, in the cutting method using the ultrasonic cutting machine of the present invention, cutting can be performed with a small waviness even when the difficulty of cutting is 2 to 5. Further, the glass can be easily cut by increasing the amplitude of the ultrasonic output of the cutting blade, that is, the amplitude of the reciprocating motion in the direction of cutting the glass.

[ glass having a cut surface ]

Next, a glass material cleaved by the cleaving method of the present invention will be described. The glass material has a small waviness, a small surface roughness Ra, and a cut surface having a high boron content on the surface according to circumstances. In the present specification, a cleaved surface refers to a surface newly generated by cleavage.

(waviness of cut surface)

The glass obtained by the method for cutting glass of the present invention has a cut surface with a small waviness. The waviness of the cut surface is the planarity of the cut surface, and is defined by a numerical value obtained by the following measurement method, and the waviness measurement method of the cut surface will be described with reference to fig. 6. The waviness was measured by pressing a vertical surface at an angle of 90 ° to the plane against the cut surface, measuring the size of the gap D between the vertical surface and the cut surface N times (in the example of the present invention, N is 5), and determining the average value of the gap D per thickness T of the glass, that is, the D/T as the waviness. When the waviness is small, the angle formed by the bottom surface of the glass and the cut surface approaches 90 °, and as shown in fig. 6, in the case of a prismatic glass, the angle approaches a rectangular parallelepiped. Therefore, the variation among the individual glass materials is also reduced, and the amount of polishing can be suppressed in the subsequent polishing step or the like, and the amount of glass cullet can be reduced. When the degree of difficulty of cleaving is 2 to 5 (for example, when the degree of difficulty of cleaving is 3), the waviness of the cleaved surface is preferably 100 or less, more preferably 80 or less, and still more preferably 60 or less.

In the case of the conventional cutting method using manual cutting, since the cut portion serving as the starting point of cutting is a point, heat spreads in a circular shape around the point. In this case, the waviness of the cut surface is large, and the waviness exceeds 100 when the difficulty of cutting is 2 to 5 (for example, when the difficulty of cutting is 3).

In contrast, in the present invention, the incision is cut linearly while applying ultrasonic waves, and therefore the incision portion that becomes the starting point of the cutting is linear. In this case, since the thermal diffusion is wide, the waviness of the cut surface is small.

(surface roughness Ra of cut surface)

The cut surface obtained according to the present invention has a smaller surface roughness Ra than the cut surface obtained by physical cutting. When the surface roughness Ra is small, the inside of the glass can be easily recognized without polishing, and impurities and the like can be visually observed. In cutting with a normal glass cutter, the surface roughness Ra is large, and the glass is rubbed into glass, so that the inside of the glass cannot be visually observed. The glass material of the present invention preferably has an Ra of at least one cut surface of 500nm or less, more preferably 400nm or less, further preferably 300nm or less, further preferably 200nm or less, further preferably 100 nm or less, particularly preferably 20nm or less, for example, 5nm or less.

(glass component)

The glass material of the present invention is not particularly limited in its composition, and can be applied to various glasses. Examples thereof include phosphate glass and/or borate glass and/or silicate glass. The present invention is easily applicable to a material having a low bending strength and a high thermal expansion coefficient.

The strength of the glass easily applicable to the present invention is preferably 100 or less, more preferably 85 or less, further preferably 75 or less, further preferably 65 or less, and further more preferably 55 or less, when 150 (unit: Pa) or less or 120 or less is used as a standard for the bending strength in a general optical glass. Further, the average linear expansion coefficient of the expansion coefficient is preferably 60X 10 in the range of 100 to 300 ℃ as a standard of the expansion coefficient^－7(unit: K)^－1) Above, more preferably 80 × 10^－7Above, more preferably 100 × 10^－7Above, more preferably 120 × 10^－7Above, still more preferably 130 × 10^－7Above, 140 × 10 is particularly preferable^－7The above.

For the bending strength σ, glass samples (number of samples, ten) having a width of 4 × thickness of 3 × total length of 40(mm) were used, which had upper and lower surfaces polished and edges chamfered by C0.2(mm) (right isosceles triangles with sides having a length of 0.2mm were removed), and the bending strength σ was measured by JIS R1601: the breaking load p (n) can be measured by the "three-point bending test method" defined in 2008, and σ can be 3PL/(2w · t)²) And (6) performing calculation.

Here, L is the distance between the supporting points (mm), w is the width of the sample (mm), and t is the thickness of the sample (mm). The obtained bending strength σ may be expressed in units of MPa, and for example, 1 MPa-1.01972 × 10 may be used^－1kgf/mm²In kgf/mm²Unit expression, and the like.

The average linear expansion coefficient α of 100 to 300 ℃ was determined by using a round glass rod having a length of 20mm and a diameter of 5mm to 4. + -. 0.5mm and heating the sample while raising the temperature thereof at a constant rate of 4 ℃ per minute by a differential thermal expansion meter, and measuring the elongation of the sample with respect to the temperature, in accordance with the measurement method of JOGIS08 of Japan optical glass Industrial Standard.

The bending strength σ is mainly determined by the content of the alkali element in the glass and SiO₂The content of (b) is determined, but is also affected by other elements. Specifically, the elements (Li, Na, K, Rb, Cs, Mg, Ca, Sr, etc.) for decreasing the bending strength sigma,Ba. Bi) is a (where the total of Li, Na, K, Rb and Cs is 10 times), and when the total of the mass percentages of the elements (Si, B, P and Nb) for increasing the bending strength σ is B, the larger the value of a/B, the easier the glass is to be cut. In terms of easy cleavage, the value of A/B is preferably 0 or more, in the order of 0.1 or more, 0.2 or more, 0.4 or more, 0.8 or more, 1.2 or more, 1.6 or more, 2.0 or more, 2.4 or more, 2.8 or more, 3.2 or more, 3.5 or more, and 4.0 or more. In addition, in a and B, the following formula (w (X) represents the mass% of the element X contained in the glass, for example, w (Li) represents the mass% of the Li component).

A＝W[(Li)+W(Na)+W(K)+W(Rb)+W(Cs)]×10+W(Mg)+W(Ca)+W(Sr)+W(Ba)+W(Bi)]

B＝[W(Si)×10]+W(B)+W(P)+W(Nb)+W(La)

The present invention can be applied to glasses other than glass having a small bending strength σ. Hard glass, that is, glass having an a/B value of 1.0 or less, or glass having an a/B value of 0.5 or less, 1 or less, or 0.0 can be cut by paying attention to the output of the cutting blade. For example, the a/B value of the glass D is 0.0, but the glass can be cut as in the examples by enlarging the amplitude of the ultrasonic output of the cutting blade, that is, the reciprocating motion in the direction of cutting the glass.

(element content and composition distribution in the cut surface)

For example, when the glass contains a silicate skeleton, elements such as alkali ions are eluted from a strong Si — O glass structure, and the content of alkali elements may decrease on the polished surface. In addition, when the glass contains boron, since boron located on the surface of the glass is in a state of being able to react with water and be eluted, the content of boron in an unprocessed free surface after the glass is manufactured (the free surface refers to a surface which is in contact with the atmosphere when the glass is solidified) or a polished surface processed by polishing using water is low. Further, when the glass contains halogen ions (chlorine, bromine, iodine, etc.) such as fluorine, the glass surface is exposed to the atmosphere due to an exchange reaction between oxygen ions on the glass surface and the halogen ions, for example, the amount of halogen ions decreases, and therefore the composition distribution on the glass surface may be different from that in the sample.

In contrast, the cleaved surface obtained by the present invention is a cleaved surface obtained by cleaving the inside (bulk glass structure) of glass to obtain a surface, and since water is not used at the time of cleaving, the composition distribution of the entire glass is uniform.

Therefore, the content of boron and/or alkali components and/or fluorine in the cut surface of the glass of the present invention is higher (in terms of atomic mass%) than the content of these elements in the glass surface such as the free surface and the polished surface of the above-mentioned surface in the glass material.

More specifically, the content of boron and/or alkali components and/or fluorine in the cut surface is preferably 5% or more, more preferably 7% or more, and still more preferably 10% or more higher than the content of these elements in the glass material, which are not contained in the glass surface such as the free surface and the polished surface of the above-mentioned surface. These values are calculated by (the content of boron and/or alkali component and/or fluorine in the cleaved surface)/(the content of these elements not contained in the surface of the glass in the cleaved surface).

When the glass sample of the present invention is deformed by heating or the like under pressure, the glass on the surface of the sample is somewhat folded into the inside of the optical element, but in this case, the difference in the distribution of components between the surface of the sample and the inside is small, and therefore, the minute difference in the refractive index between the surface of the sample and the inside is also small, and therefore, an optically homogeneous optical element can be obtained. This effect is particularly pronounced when the lens is used in a higher performance optical system.

[ examples ]

Examples

The present invention will be further described with reference to the following examples. The present invention is not limited to the examples.

[ ultrasonic cutting machine ]

As the ultrasonic cutting machine, an ultrasonic small-sized cutting machine USW-334 manufactured by this Multi-electronics Co. The ultrasonic vibration blade is made of SKH51, and ultrasonic vibration with frequency of 22kHz and amplitude of 5-30 μm is applied to perform the following cutting.

[ production of glass Material by cleaving ]

(measurement of optical glass Properties)

Raw materials such as optical glass grade high-purity oxides, hydroxides, carbonates, nitrates, chlorides, fluorides, sulfates and the like were used, and the raw materials were weighed and mixed to obtain glasses (glass E) having the components described in the items of the glasses a to D of table 1 and the cleaved surface of table 4 as a blended raw material. Next, each prepared raw material was placed in a platinum crucible, heated to a predetermined temperature as described above, melted for two or four hours from the start of melting in a nitrogen atmosphere, homogenized by stirring, left to stand for clarification, and poured into a mold. After the glass was solidified, the glass was transferred to an electric furnace heated to a temperature close to the slow cooling point of the glass, and slowly cooled to room temperature. Thus, a block made of the glass of each example was produced. From each of the obtained glass blocks, a glass having a predetermined size necessary for measurement was cut out, and subjected to polishing to evaluate the characteristics. The glass a to D are shown in table 1 and table 2 for the components and properties, and table 3 for the results of cleaving. The glass E has the composition of the cut surface, polished surface, and free curved surface shown in table 4.

In the case of reproducing examples, samples for cutting may be prepared using raw materials capable of forming about 200g, 300g, 400g, and 500g of glass, or glass having a volume larger than that described in the examples may be cut out and cut, depending on the specific gravity of the glass.

(embodiment one)

The glass a of 10mm (thickness) × 10mm (width) × 100mm (length) was cut into a rectangular parallelepiped of 10mm (thickness) × 10mm (width) × 20mm (length after cutting), and the base material glass was pressed with a hand to generate tensile stress in the notch of the glass material and to cut the glass by bringing the ultrasonic cutter into contact with a portion to be cut with a cutting difficulty of 0.50, after the notch was cut by ultrasonic vibration, thereby obtaining a cut piece a 1.

(second embodiment)

The length after the cutting was changed to 15mm, and glass A of 10mm (thickness) × 10mm (width) × 100mm (length) was cut in the same manner as in examples with the ease of cutting being 0.69, to obtain cut pieces A2.

(third embodiment)

The length after the cutting was changed to 10mm, and glass A of 10mm (thickness) × 10mm (width) × 100mm (length) was cut in the same manner as in examples with the ease of cutting being 1.25, to obtain cut pieces A3.

(example four)

The thickness was changed to 20mm, the width was changed to 20mm (width), the length after cutting was changed to 20mm, and glass a of 20mm (thickness) × 20mm (width) × 100mm (length) was cut in the same manner as in examples with the ease of cutting being 3.00, to obtain a cut piece a 4.

(fifth embodiment)

Glass a having a thickness of 20mm (thickness) × 38mm (width) × 100mm (length) was cut in the same manner as in examples with a difficulty of cutting of 4.66 by changing the thickness to 20mm, the width to 38mm (width) and the length after cutting to 38mm, thereby obtaining a cut piece a 5.

(sixth embodiment)

The cutting was carried out in the same manner as in the examples except that the glass a was changed to the glass B, to obtain a cut sheet B1.

(seventh embodiment)

Cleaving was performed in the same manner as in example three except that the glass a was changed to the glass B, and a cut piece B2 was obtained.

(eighth embodiment)

The length after the cutting was changed to 7.5mm, and the cut piece was cut in the same manner as in example seven with the ease of cutting set to 2.03, to obtain a cut piece B3.

(example nine)

The cutting was carried out in the same manner as in the examples except that the glass a was changed to the glass C, to obtain a cut piece C1.

(example ten)

Cleaving was performed in the same manner as in example two except that the glass a was changed to the glass C, to obtain a cut sheet C2.

(example eleven)

Cleaving was performed in the same manner as in example three except that the glass a was changed to the glass C, and a cut piece C3 was obtained.

Example twelve

Glass C15 mm (thickness) × 15mm (width) × 100mm (length) was cut in the same manner as in example nine with the thickness changed to 15mm, the width changed to 15mm, and the length after cutting changed to 15mm, and the ease of cutting was 2.06, to obtain a cut piece C4.

(thirteen in example)

The length after the cleavage was changed to 12.5mm, and the obtained product was cleaved in the same manner as in example twelve with the degree of difficulty of cleavage being 2.72, to obtain a cut piece C5.

(example fourteen)

The length after the cleavage was changed to 10mm, and the obtained product was cleaved in the same manner as in example twelve with the degree of difficulty of cleavage being 3.94, to obtain a cut piece C6.

(example fifteen)

The cutting was carried out in the same manner as in example three except that the glass a was changed to the glass D, to obtain a cut piece D1.

[ measurement of waviness of cut surface ]

With respect to waviness, a vertical surface at an angle of 90 ° to a plane was pressed against a cleaved surface cleaved in the examples, the size of the gap D between the vertical surface and the cleaved surface was measured five times, and the gap D per thickness T of glass, that is, the average value of D/T was measured as waviness.

An L-shaped holder (manufactured by Sigma optical instruments) was used as a device for measuring waviness (see fig. 6). The results are shown in FIG. 7. The waviness of the samples obtained by the present invention is about the same as that of the samples obtained by the present invention in hand cutting, but even if the ease of cutting is 0.30 or more, 0.50 or more, 0.70 or more, 0.90 or more, 1.00 or more, 1.25 or more, 1.50 or more, 1.75 or more, 2.00 or more, for example, even if it is 1.00 to 5.00, the waviness is smaller than that of hand cutting, and the samples can be cut into desired sizes.

[ Table 1]

[ Table 2]

[ Table 3]

[ measurement of surface roughness Ra of cut surface ]

For measurement of the surface roughness Ra of the glass, NewView7300 manufactured by ZYGO was used as a scanning white interferometer. The measurement range was 0.36 mm. times.0.27 mm. The roughness Ra of the glass A cut into pieces of 10 mm. times.10 mm was 14.98nm (the glass material of example 3 was used).

On the other hand, as a reference example of the glass surface not included in the cleaved surface described in the present invention, when the glass a is cut to 10mm × 10mm × 10mm by a glass cutter (including a round blade embedded with diamond abrasive grains), the glass surface is in a state of rubbing the glass, and thus the inside of the glass cannot be observed. Ra is 1000 μm and is larger than the cleavage plane Ra.

Further, as a reference example, the glass a was cut into pieces of 10mm × 10mm × 10mm, and the Ra of the polished surface when the cut surface was polished was 1.19.

[ measurement of elemental composition of surface ]

The elemental composition of the surface of the glass E was measured by X-Ray Photoelectron Spectroscopy (X-surface roughness Ray photon Spectroscopy, abbreviated as XPS). K-Alpha + manufactured by Thermo Fisher Scientific was used as an X-ray photoelectron spectrometer.

The elemental composition (atomic% unit) of the surface was measured for the cleaved surface cleaved with the ultrasonic cutter described in the present specification and the non-cleaved surface (polished surface and free surface) described in the present specification. The results are shown in Table 4. On the surface of the glass, the content of carbon and oxygen tends to increase due to the formation of carbonate by the reaction with carbon dioxide and water in the air as compared with the inside of the glass, and the content of ions such as boron and alkali elements which are easily eluted into water tends to decrease.

[ Table 4]

Claims

1. A method of severing glass, comprising: bringing an ultrasonic vibration blade of an ultrasonic cutting machine into contact with a portion of glass to be cut; a step of subjecting the ultrasonic vibration blade to ultrasonic vibration; and cutting a notch while linearly generating frictional heat on the glass by the ultrasonic wave.

2. A method for cutting glass according to claim 1, wherein the frequency of the ultrasonic vibration is 5kHz or more and 50kHz or less.

3. A method for cutting glass according to claim 1 or 2, wherein the amplitude of the ultrasonic vibration is 5 μm or more and 40 μm or less.

4. A glass material obtained by the cleaving method according to claim 1.

5. A cleaving method according to claim 4, wherein a waviness of a cleaved surface of the glass material is 100 or less.

6. A method for producing a glass material, comprising: bringing an ultrasonic vibration blade of an ultrasonic cutting machine into contact with a portion of glass to be cut; a step of subjecting the ultrasonic vibration blade to ultrasonic vibration; and cutting the glass into a notch while linearly generating frictional heat by the ultrasonic wave.

7. A glass material characterized by having at least a surface with waviness of 100 or less and surface roughness Ra of 500 [ mu ] m or less.

8. The glass material of claim 7, wherein the face is a cut face.

9. The glass material according to claim 7 or 8, wherein a content ratio of boron and/or alkali component and/or fluorine in the face is higher than a content ratio of these elements which are not contained in a glass surface of the face in the glass material.

10. The glass material according to claim 7 or 8, wherein a content of boron and/or alkali components and/or fluorine in the surface is 5% or more higher than a content of these elements which are not contained in the glass surface of the surface in the glass material.