JP2000154031A - Method for cutting planar glass preform, production of preform and device for cutting planar glass preform - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the floating of cut pieces at the time of pressurizing and cutting in a method for cutting a planar glass preform previously scribed with a plurality of grooves on one main surface. SOLUTION: When a presser 191 cuts the material 20 to be cut, the cut pieces of the material 20 to be cut tend to float up. However, buffer members 193a, 193b are mounted at the circumference of the presser 191 and, therefore, these buffer members 193a, 193b properly press down the cut pieces to prevent the floating up thereof. The colliding of the adjacent cut pieces against each other and the chipping of their corner parts may, therefore, be prevented. The press blank of a uniform weight may, thereby, be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a sheet glass base material, which is a base material of a press material used in a reheat press method, and an apparatus for cutting a sheet glass base material. The present invention relates to a method for cutting a sheet glass base material in which grooves are prescribed and a sheet glass base material cutting apparatus.

[0002]

2. Description of the Related Art When forming optical elements such as optical lenses and prisms, press molding is used. As a method of this press molding, mainly, a precision press molding method,
There are a direct press method and a reheat press method.

[0003] The precision press molding method is a molding method for transferring the shape and surface precision of a molding die to a softened glass, and a pressed product does not require grinding and polishing. In contrast,
The direct press method and the reheat press method are molding methods on the premise that after press molding, grinding for bringing the shape of the pressed product closer to the shape of the final product and polishing for polishing the surface of the pressed product are performed. However, even in the reheat press method, when the weight of the press material is accurate and the surface is good, polishing is not required, and a reheat press free of polishing is possible.

Since the precision press molding method is free of polishing, it is suitable for manufacturing a lens having a shape difficult to be polished, such as an aspherical lens. ^It must be pressed in a relatively high place of ⁸ to ¹² dPa · S, and only a glass material that satisfies the condition that this press viscosity does not cause devitrification can be used.
Further, there is a problem that the manufacturing apparatus is large-scale and expensive, and the manufacturing cost increases.

Therefore, the direct press method and the reheat press method are suitable for producing a large amount of glass products while suppressing the production cost. In the direct press method, a predetermined amount of molten glass flowing out of an outflow pipe is poured onto a lower mold of a forming die and pressed at a relatively low viscosity of around 10 ³ dPa · S. According to this method, although the weight accuracy of the press-formed product is good, it is not suitable for high-mix low-volume production.

[0006] On the other hand, in the reheat press method, a press material having a predetermined weight is prepared, the press material is reheated (reheated) from normal temperature, softened, and pressed with a molding die at a viscosity of around 10 ⁵ dPa · S. Molding. This method is not suitable for mass production of small varieties, but is suitable for mass production of many varieties. In this reheat press method, if the weight of the press material is insufficient for the cavity of the press mold, the press material cannot fill the cavity of the mold,
There is a problem in that elongation is poor, and even if the weight of the press material is too large, it will protrude from the mold. Therefore, in the reheat press method, adjusting the weight of the press material is a major issue.

Conventionally, as a method for forming a press material used in the reheat press method, there is Japanese Patent Application No. 9-359522 filed by the present applicant. According to the present invention, a plurality of lattice-shaped grooves are scribed in advance on one main surface of a plate-shaped glass base material which is a base material of a press material. Then, the plate-shaped glass base material is placed on the cushioning member so that these grooves are at the bottom, and a portion facing the grooves is pressed from above by a rod-shaped indenter, and cracks are generated by stress concentration generated in the grooves. Grow and cut.

FIG. 10 is a view schematically showing a method of cutting a sheet glass base material according to Japanese Patent Application No. 9-359522. When cutting the sheet glass base material 41, the cutting auxiliary member 42 is fixed on a mounting table (not shown), and the sheet glass base material 41 is mounted thereon. The cutting auxiliary member 42 is formed of a material having a lower Young's modulus than the sheet glass base material 41. In the plate-like glass base material 41, grooves 41a and the like are formed in a lattice shape in advance. Each groove 41a is scribed so as to have a crack in the vertical direction. Such a plate-like glass base material 41 has a main surface 4 on which a groove 41a is formed.
It is placed on the cutting auxiliary member 42 such that 11 is below.

The side surfaces of the plate-shaped glass base material 41 and the cutting auxiliary member 42 are held by positioning members 43 and 44 and the like. At this time, the glass preform 41 is
It is mounted so as to protrude above the positioning members 43 and 44 by a predetermined amount L1. The predetermined amount L1 is always set to a constant value irrespective of the thickness of the sheet glass base material 41. Then, the position of L1 from the upper surfaces of the positioning members 43 and 44 is set as the origin of the pushing amount of the indenter 46.

[0010] The plate-like glass base material 41 installed as described above.
Is performed by a rod-shaped indenter 46 fixed to the indenter stand 45. That is, the indenter 46 is lowered together with the indenter stand 45, and a portion of the upper main surface 412 facing the groove 41 a is pressed by the indenter 46. By this pressing, a bending stress is applied to the groove 41a, a crack grows, and the groove is finally cut.

When the cutting is completed for all the grooves, a large number of press materials having a uniform weight are formed.

[0012]

However, in the above-described cutting method, a phenomenon occurs in which the cut piece floats around the groove during pressurization. When floating occurs, there occurs a problem that adjacent cut pieces collide with each other and a corner is chipped. If the corners are missing, it is not possible to form a press material having a uniform weight, and in severe cases, the cut pieces will jump out and cannot proceed to the next step. Further, since L1 is always set to a constant value, when the plate-shaped glass base material 41 is thin, the portion held by the positioning members 43 and 44 becomes thin, so that the interference between the cut pieces may occur. Will increase further.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a method of cutting a sheet glass base material and a sheet glass cutting material cutting apparatus capable of preventing floating of cut pieces. With the goal.

[0014]

According to the present invention, in order to solve the above-mentioned problems, in a method for cutting a sheet-like glass base material in which a plurality of grooves are preliminarily scribed on one main surface, the grooves are set inside. The plate-shaped glass base material is disposed, and while pressing the outer surface of the plate-shaped glass base material with a buffer member, a portion of the outer surface facing the groove is pressed by a pressing indenter having an elongated shape. Thus, there is provided a method for cutting a sheet glass preform, which comprises cutting the sheet glass preform.

In this cutting method, first, a sheet glass base material is arranged with the groove inside. Then, while holding the outer surface of the plate-shaped glass base material with the cushioning member, a portion of the outer surface facing the groove is pressed by an elongated pressing indenter to cut the plate-shaped glass base material. This prevents the cut pieces from being lifted after cutting.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a plan view showing the configuration near the mounting table of the sheet glass preform cutting apparatus of the present embodiment. Also,
FIG. 3 is a sectional view taken along line A1-A1 in FIG. The plate glass preform cutting device 10 is provided with a mounting table 11 for mounting the plate glass preform. This mounting table 11
Is provided so as to be able to reciprocate in the X-axis direction in FIG.
At the start of the operation, the mounting table 11 is arranged such that its center point P0 coincides with the origin of the XY coordinate system. Further, the mounting table 11 is provided so as to be rotatable about the center point P0 in the XY plane. The movement and the rotation of the mounting table 11 are executed by a drive mechanism described later.

A reference plate 12 is fixed on the mounting table 11. The reference plate 12 is an L-shaped member, and has positioning members 1 on its inner surfaces 12a and 12b.
3, 14 are fixed. Positioning members 13, 14
Is formed of a material having a Young's modulus lower than that of the glass substrate, for example, an elastic material such as natural rubber, so that chipping or the like does not occur when the sheet glass base material is cut.

A substantially square, plate-shaped cutting auxiliary member 30 is mounted on the mounting table 11. The cutting auxiliary member 30 is pressed against the positioning members 13 and 14 of the reference plate 12 by the pressing device 17 and the pressing device 18. Pressing plate 17 of pressing device 17
A positioning member 15 made of natural rubber is fixed to a. The pressing device 17 includes the positioning member 1.
At 5, the cutting auxiliary member 30 is pushed in the X-axis direction, and is pressed against the positioning member 13 of the reference plate 12.

Similarly, the pressing plate 1 of the pressing device 18
A positioning member 16 made of natural rubber is fixed to 8a. The pressing device 18 includes the positioning member 16.
Press the cutting auxiliary member 30 in the Y-axis direction with
2 is pressed against the positioning member 14 side. Thus, the cutting auxiliary member 30 is positioned and fixed on the mounting table 11.

On the cutting auxiliary member 30, the cutting auxiliary member 3
Four plate-shaped glass preforms 2 in a range slightly smaller than 0
The material to be cut 20 consisting of 1, 22, 23, and 24 is placed. The plate-shaped glass base materials 21, 22, 23, and 24 are square plate-shaped members having substantially the same size, and are placed so as to be in close contact with each other and to be in close contact with the positioning members 13, 14. At this time, as shown in FIG. 3, the workpiece 20 has the upper main surface 20a having the positioning members 13, 14, 15, 1
6 protrudes from the upper side by a certain amount. The main surface 20a of the workpiece 20 is set at the reference position of the pressing stroke.

Further, since the size of the flat surface of the workpiece 20 is smaller than that of the cutting auxiliary member 30,
An appropriate gap is provided between the positioning members 3 and 24 and the positioning members 15 and 16. The clearance secures an escape space for the glass at the time of cutting.

In such a mounting table 11, the workpiece 20
The dimensions of each member are designed such that when the is mounted, the center thereof coincides with the center point P0 of the mounting table 11. A pressurizing device 19 is provided above the mounting table 11, as shown in FIG. The indenter table 190 of the pressurizing device 19 is connected to the axis of the Z-axis servomotor 192 via a ball screw 192a. The indenter table 190 is a Z-axis servo motor 1
With the rotation of 92, it moves up and down along the Z axis. Indenter stand 1
A round bar-shaped indenter 191 extending in the Y-axis direction is fixed to the lower surface 190a of the 90. The indenter 191 is, as will be described later, each plate-like glass base material 21, 22, 2 of the workpiece 20.
It is a member that presses and cuts 3, 24 from above, and is formed in a shape that is extended to have substantially the same length as a groove described later.

On the lower surface 190a of the indenter table 190,
The buffer member 193 is attached. Buffer member 193
As shown in FIG. 4, two cushioning members 193 are provided.
a, 193b are used, and the lower surface 19 except for the indenter 191 is used.
0a is attached almost to the front. Buffer member 193
For a and 193b, a material having hardness enough to prevent the cut piece of the material to be cut 20 from floating and moderate flexibility not damaging the cut piece is used. Also, the cushioning members 193a, 19
3b has a thickness that does not protrude below the lowermost portion 191a of the indenter 191.

As a member meeting these conditions, for example, there is a polishing sheet for polishing a lens. Specifically, it is a resin member having a porous layer, for example, having a total thickness of 0.70 m
m to 1.5 mm, thickness of the porous layer is 400 μm to 450 μm
m, pore diameter 50 μm to 90 μm, hardness 50 degrees to 80
Degree, compression ratio 4% ~ 8%, compression elasticity 60% ~ 80%
Is used. More preferably, the total thickness is 0.1 mm.
70 mm, the thickness of the porous layer is 400 μm, and the pore size is 60 to 8
0 μm, hardness 70 °, compression ratio 6. % And a compressive modulus of about 72%.

FIG. 5 is a view showing the structure of the drive mechanism of the mounting table 11. As shown in FIG. Here, a plan view in a state where the mounting table 11 in FIG. 2 is removed is shown. The drive mechanism unit 110 includes X
The axis servo motor 112 is fixed. A ball screw 113 is attached to the axis of the X-axis servo motor 112.

A base 111 is screwed into the ball screw 113, and moves in the X-axis direction according to the rotation of the ball screw 113. On the other hand, the support board 114 is rotatable around a point overlapping the center point P0 of the mounting table 11. Also,
A pinion portion 114a is formed on the periphery of the support board 114. This pinion portion 114a is
It meshes with 16 rack portions 116a. Rack member 1
16 is connected to the cylinder 115 and the cylinder 1
15 moves in the X-axis direction in response to the drive of No. 15.

In such a drive mechanism 110, when the mounting table 11 is moved, the X-axis servo motor 112 is driven to move the base 111. The cylinder 11
The support plate 114 is rotated by the driving of 5. However, the rotation of the support plate 114 is controlled by the mechanical stopper 11.
7, 118, it is possible to rotate only in the range of 90 °.

Next, a specific configuration of the material to be cut 20 will be described. FIG. 6 is a plan view showing the configuration of the workpiece 20. FIG. 7 is a front view of FIG. Material to be cut 20
Of the four plate-shaped glass base materials 21, 22, 23, 2
4 is a plate-like glass having a square planar shape. On the lower main surface 20b on the lower side of these plate-shaped glass base materials 21, 22, 23, and 24, 18 pieces each in the vertical and horizontal directions, a total of 36
The grooves D1 to D36 are formed in a lattice shape and have a V-shaped cross section. Thereby, the plate-shaped glass base material 21,
Each of 22, 23, and 24 is partitioned into 10 × 10 = 100 blocks.

The grooves D1 to D36 are arranged in the same arrangement as when they are mounted on the plate-like glass preform cutting device 10, and are turned upside down (the main surface 20b side is turned up) into a dedicated scribing device. Installed and formed. At this time, the grooves D1 to D36 are formed so that cracks are generated substantially in a direction perpendicular to the main surface 20b.

The workpiece 20 having such a configuration is shown in FIG.
As shown in FIG. 3, the wafer is placed on the cutting assisting member 30 and cut in order from the groove located at a position where a large bending moment is received when pressurized. For example, plate-like glass base materials 23, 2
4, a groove D14 common to the plate glass base materials 21 and 22 is first provided, and a groove D5 common to the plate glass base materials 21 and 22 is further provided with a groove D23, a groove D32, and a groove D34.
The grooves D30 are cut in this order.

Next, a specific configuration of the cutting auxiliary member 30 will be described. FIG. 8 is a plan view showing the configuration of the cutting auxiliary member 30. FIG. 9 is a side view of the cutting auxiliary member 30, and FIG.
(B) is a side view as seen from the direction of arrow Y1 in FIG. 8. As described above, the cutting auxiliary member 30 is formed such that the length in the vertical and horizontal directions is slightly longer than the length of the material to be cut 20. The cutting auxiliary member 30 includes a base block 31 and contact members 32 and 3 provided between the base block 31.
3, 34, 35, 36, 37, 38, 39,
These are integrally formed.

The base block 31 is made of urethane rubber. On the other hand, the contact members 32 to 39 are made of natural rubber and formed to have a thickness of about 5 mm. Further, as shown in FIG. 9, the contact members 32 to 39 are formed so that the heights of the upper surfaces thereof substantially coincide with each other and slightly protrude from the upper surface of the base block 31. The amount of protrusion and the material of each contact member are selected according to the pressure at which the workpiece 20 is cut.

As shown in FIG.
As shown in the figures, four plate-shaped glass base materials 21, 22, 23, and 24 are placed as the material to be cut 20. At this time, as shown in FIG. 9, the groove D14 is located on the contact member 32, the groove D5 is located on the contact member 33, the groove D32 is located on the contact member 34, and the groove D23 is located on the contact member 35. Is placed.

Next, the sheet glass preform cutting device 1 of the present embodiment
The operation of 0 will be described. First, before starting the cutting operation, the center point P0 of the mounting table 11 is located at the origin of the XY coordinates as shown in FIGS. On the other hand, the pressurizing device 19 is at a position sufficiently higher than the mounting table 11 as shown in FIG. At this time, the mounting table 11 is set so that the first cut groove D14 of the workpiece 20 coincides with the Y axis, that is, the mounting table 11 overlaps the indenter 191 of the pressing device 19 on the XY plane. , The position and orientation are controlled.

When the positioning is completed, the Z-axis servo motor 192 operates and the indenter 191 descends, and comes into contact with the position on the main surface 21 of the glass preform 20 facing the groove D14. When the indenter 191 further descends and pressurizes from this state, the crack in the groove D14 is enlarged and cut. The stroke of the pressurization of the indenter 191 is determined in advance for each groove, and the cutting operation is stopped when the presser 191 moves by the determined pressurization stroke.

When the cutting of the groove D14 is completed, the indenter table 19
0 is retracted upward, then the mounting table 11 slides in the X-axis direction, and this time, the groove D5 is positioned so as to coincide with the Y-axis. This groove D5 is also pressed and cut by the indenter 191 similarly to the groove D14. Next, the mounting table 11 is rotated by 90 °, and is positioned and cut, for example, so that the groove D23 coincides with the Y axis. Thereafter, the remaining grooves are cut in the determined order by the same procedure. By cutting all the grooves, a total of 400 press blanks are formed.

FIG. 1 is a side view showing a state immediately after cutting the workpiece 20 by the indenter 191. When the indenter 191 cuts the workpiece 20, the cut pieces of the workpiece 20 tend to float. However, in the device of the present embodiment, the indenter 191
Since the cushioning members 193a and 193b are attached around the cutout, the cushioning members 192a and 193b appropriately press the cut pieces to prevent floating. For this reason, it is possible to prevent the adjacent cut pieces from colliding with each other and chipping off the corners. Therefore, a pressed material having a uniform weight can be formed. In addition, since the cut pieces can be prevented from jumping out, unnecessary interruption during work is eliminated, and the efficiency is improved. Further, since the cut pieces are held by the buffer members 193a and 193b, the cut piece surface is not damaged.

Further, in this embodiment, since four plate-shaped glass base materials 21, 22, 23, and 24 are set at the same time and cut, the work time is reduced as compared with the case where four sheets are cut separately. Is done. As a result of actually dividing the four plate-shaped glass base materials 21, 22, 23, and 24 of 50 cm square into 400 pieces, 400 cut pieces with little weight variation were cut in half the time of the cutting method for each piece. Could be formed.

However, in this method, the number of cut pieces increases in the latter half of the operation, and the cut pieces tend to interfere with each other.
However, in the present embodiment, the lifting is prevented by the buffer members 193a and 193b, so that the cut pieces can be prevented from being buffered, and the occurrence of chipping can be prevented. Therefore, a high-speed press material of high quality can be provided.

Further, in the present embodiment, when grooves are formed in the four sheet glass base materials 21 to 24, they are set in the scribing device in the same arrangement as at the time of cutting, and four sheets are scribed simultaneously. Even if there is an error in the shape of the sheet glass preforms 21 to 24, when set in the sheet glass preform cutting device 10, the position and direction of the groove do not shift between the sheet glass preforms. Therefore, since the direction of the indenter 191 and the direction of each groove can always be made coincident, cutting can be performed accurately. In this sense, it is possible to provide a high-speed press material at high speed.

As described above, a plurality of polishing-free optical lenses were produced by the reheat press method using the press material formed according to the present embodiment. As a result, a uniform pressed product was obtained.

In this embodiment, the cutting is performed with a predetermined pressure stroke for each groove.
A sensor such as a vibration sensor for detecting cutting may be attached to 91 or the like, and the pressurizing operation may be stopped simultaneously with the detection of cutting.

Next, Table 1 shows an example in which a reheat press is performed using the press material formed according to the present embodiment.

[0044]

[Table 1]

As shown in Table 1, Examples 1 to 3
Boric acid-lanthanum (B_TwoO_Three-La_TwoO_Three) Series glass
Using seeds, Examples 4-6 were prepared using silica-boric acid (SiO_Two
-B _TwoO_Three) Series glass type was used.

Specifically, the press material formed according to the present embodiment was barrel-polished to reduce corners of the press material and roughen the surface, and then a release agent such as boron nitride was uniformly applied to the surface of the press material.

The barrel-polished press material is heated from room temperature, and the heat-softened press material is placed on the lower die of the press mold via the loading means. Thereafter, when the viscosity of the heat-softened press material was 10 ⁴ to ⁶ dPa · S, and preferably 10 ⁵ dPa · S, the press material was subjected to collective press molding using a plurality of molds having a molding surface corresponding to the final lens shape. The mold is composed of an upper mold and a lower mold, and may have a body mold. This press molding was performed in an air atmosphere.

As shown in Examples 1 to 3, boric acid-lanthanum (B ₂ O ₃ -La ₂ O ₃ ) glass was used as the press material, and the press materials were 830 ° C., 780 ° C., and 750 ° C., respectively.
° C and softened state (10 ⁴ , 10 ⁵ , 10 ⁶ dPa
In step S), the material is introduced into the molding surface of the lower mold heated to 640 ° C., 660 ° C., and 665 ° C. by the loading means. Next, the softened press material was pressed against the upper mold heated to 650 ° C., 670 ° C., and 675 ° C., respectively, by pressing the lower mold against the upper mold.
Press molding was performed at kg / cm ² for 4 seconds, 2 to 3 seconds, and 2 seconds.

Further, as shown in Examples 4 to 6, silica-boric acid (SiO ₂ -B ₂ O ₃ ) glass was used as the press material, and the press materials were 950 ° C., 870 ° C., 79 ° C., respectively.
Heated to 0 ° C. and softened (10 ⁴ , 10 ⁵ , 10 ⁶ dP
a), the material is introduced into the molding surface of the lower mold heated to 630 ° C., 650 ° C., and 655 ° C. by the carrying-in means. Next, the softened press material was pressed against the upper mold heated to 640 ° C., 660 ° C., and 665 ° C. by pressing the lower mold against the upper mold, and the pressed material was 25, 30, and 35 kg / c.
At m ² , press molding was performed for 4, ² to 3 and ² seconds, respectively.

Since the weight variation of the press material is small,
Upon reheat pressing, poor stretch of the press material and protrusion of the press material from the mold were not observed. Pressed products created by this reheat press are rough-
Fine grinding and polishing were performed to obtain the final product.

[0051]

As described above, according to the present invention, the plate-like glass base material is arranged with the groove inside, and the outside surface of the plate-like glass base material is opposed to the groove on the outside surface while being held down by the buffer member. The part to be pressed by a pressurized indenter in the stretched shape,
Since the plate-shaped glass base material is cut, floating of the cut pieces can be prevented. Therefore, it is possible to prevent the adjacent cut pieces from colliding with each other and the corners from being chipped. Therefore, a pressed material having a uniform weight can be formed.

Further, since the cut pieces can be prevented from jumping out, unnecessary interruption during the operation is eliminated and the efficiency is improved. Further, since the cut piece is held by the cushioning member, the cut piece surface is not damaged.

[Brief description of the drawings]

FIG. 1 is a side view showing a state immediately after cutting a material to be cut by an indenter.

FIG. 2 is a plan view showing a configuration near a mounting table of the sheet glass preform cutting apparatus of the present embodiment.

FIG. 3 is a sectional view taken along line A1-A1 of FIG. 2;

FIG. 4 is a diagram showing a mounting structure of a buffer member.

FIG. 5 is a diagram showing a configuration of a driving mechanism of the mounting table.

FIG. 6 is a plan view showing a configuration of a material to be cut.

FIG. 7 is a front view of FIG. 6;

FIG. 8 is a plan view showing a configuration of a cutting auxiliary member.

9A and 9B are side views of the cutting auxiliary member, in which FIG. 9A is a side view as viewed from the direction of arrow X1 in FIG. 8, and FIG. 9B is an arrow Y1 in FIG.
It is the side view seen from the direction.

FIG. 10 is a view schematically showing a method of cutting a sheet glass base material according to Japanese Patent Application No. 9-359522.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 sheet glass base material cutting device 11 mounting table 19 pressurizing device 20 material to be cut 21, 22, 23, 24 sheet glass base material 30 cutting auxiliary member 191 indenter 193a, 193b buffer member

Claims (7)

[Claims] 1. A method for cutting a sheet glass base material having a plurality of grooves preliminarily scribed on one main surface, wherein the plate glass base material is disposed with the grooves inside. While holding the outer surface of the base material with a cushioning member, a portion of the outer surface facing the groove is pressed by a pressing indenter having an elongated shape to cut the plate-shaped glass base material. Cutting method of the sheet glass base material to be used. 2. A method for cutting a sheet glass base material in which a plurality of grooves are pre-scribed on one main surface, wherein the plate glass base material is arranged with the grooves inside, and the grooves are extended. When the glass member to be cut is cut by pressing sequentially with the pressing indenter having the shape as described above, the glass member after cutting is cut so that the glass member to be cut is prevented from being damaged by contact with the adjacent cut glass member. A method of cutting a plate-like glass base material, which suppresses inclination in a thickness direction of a glass member due to a reaction force of the cutting. 3. A method for cutting a sheet glass base material in which a plurality of grooves are pre-scribed on one main surface, wherein a plurality of sheet glass base materials are arranged side by side on a plane and stretched. A method for cutting a plate-shaped glass base material, comprising simultaneously pressing and cutting grooves on the same straight line among the grooves of each of the plate-shaped glass base materials with a pressing indenter. 4. The method according to claim 4, wherein the grooves are formed in advance by arranging the plurality of sheet glass preforms in the same arrangement as at the time of cutting. 5. A method for producing a preform used for press-molding a glass material softened by a molding die, wherein a glass material used as a starting material is produced by the method according to any one of claims 1 to 4. A method for producing a preform. 6. A sheet glass preform cutting device for cutting a sheet glass preform having a plurality of grooves pre-scribed on one main surface, wherein the main surface having the grooves is directed inward. A mounting table on which the plate-shaped glass base material is mounted in a state where the plate-shaped glass base material is placed, a pressing indenter having an elongated shape for pressing the mounted plate-shaped glass preform from outside, and holding the pressing indenter. An indenter stand, a cushioning member attached to the indenter stand and pressing the plate-like glass base material from the outside at the time of cutting, and the indenter stand to press a portion facing each groove of the plate-like glass base material, and An indenter moving mechanism for moving the pressing indenter; and driving the indenter moving mechanism to move the pressing indenter relative to the sheet glass base material, thereby forming each groove of the sheet glass member. Pressurizing the part facing the And a pressure cutting control means. 7. The apparatus according to claim 6, wherein the pressing indenter has a curved surface and protrudes from a surface of the buffer member.