JP6468385B2 - Sheet glass cutting apparatus and method - Google Patents

Description

  The present invention relates to a sheet glass cutting device and method for cutting a full body (full thickness) in a non-contact manner with a glass plate without damaging the surface of the cut glass on the planned cutting line.

  The method of dividing a large plate glass into small parts is to insert a scribe line (scratch) on the surface of the planned cutting line with a carbide tool blade such as tungsten carbide or polycrystalline diamond, and apply bending stress in the direction perpendicular to the scribe line. Fracturing with a mechanical technique is a common technique that has been performed over the past century.

  However, with such a mechanical cutting method, small pieces called “chirico” are generated when the material is folded, and the surface and cut surface of the cut glass are contaminated. In addition, due to the folding, innumerable minute scratches called “microcracks” are generated on the cut surface, and the mechanical strength of the cut glass is lowered.

  In addition, with thick glass (for example, with a plate thickness exceeding 15 mm) that is mainly used for buildings, it is difficult to apply a uniform shearing force on the planned cutting line when it is folded. There is a problem that cut defects as described in JIS R3202 such as “corner”, “cutting edge”, “scratch”, and “escape” are likely to occur.

  On the other hand, instead of the mechanical cutting method, in recent years, a thermal stress cutting method using laser light irradiation has come to be used. According to this method, the disadvantages inherent in the conventional mechanical cutting method, contamination of the cut glass due to the occurrence of “chiriko” at the time of cutting, and reduction in glass strength due to the occurrence of “microcracks” can be avoided, and mechanical It is said that a high-strength cut surface can be obtained compared to a simple cutting method.

  As such a laser cutting method for plate glass, a patent application of Patent Document 1 has been made. Patent Document 1 discloses a method of cutting a thin glass (for example, a thickness of 0.7 mm) for a flat panel display.

  In this method, an initial crack for starting cutting on the glass end surface is generated by a mechanical method, and then the glass surface is heated by irradiating a laser beam for heating along a planned cutting line from the glass end surface. A large tensile stress is generated on the glass surface by rapidly cooling the glass surface with the cooling fluid. The tensile stress concentrates on the initial crack or the tip of the scribe line that has continued from the initial crack, so that the crack progresses in the vertical direction from the glass surface, and a scribe line is formed along the planned glass cutting line. Finally, the glass on which the scribe line is formed is subjected to a bending stress by a mechanical method along the scribe line to complete the breaking of the glass. Sometimes called).

  On the other hand, patent applications of Patent Documents 2 and 3 have been made as laser cutting methods for thick glass.

  Patent Document 2 uses a wavelength tunable laser to absorb laser light at the entire plate thickness from the front surface to the back surface of the object to be cut according to the absorption characteristics of the object to be cut with respect to the laser light wavelength. The present invention relates to full body cutting of a brittle material in which the scribing depth extends in the entire thickness direction of the object to be cut by selecting a suitable wavelength of the laser beam, and a break process is not required.

  Further, Patent Document 3 preliminarily heats a pre-cleaving position by preheating it with a surface heat source, applying a tensile stress due to thermal stress to the cleaving position of the glass and holding it in a state immediately before cleaving. A method of increasing the tensile stress by scanning a local heat source at a planned cutting position and cutting the full body along the planned cutting position is disclosed. This method makes it possible to perform full-body cutting of the glass sheet while preliminarily heating the sheet glass and then irradiating a laser in the thickness direction of the glass sheet to adjust the cutting speed.

  In addition to the cutting using the laser as described above, in Patent Document 4, the near-infrared light is condensed to preheat the laminated glass, and after reducing the strength of the glass plate of the laminated glass, the shear force Discloses a method of breaking the laminated glass by adding. Patent document 4 reduces the glass strength of the said heating part (cutting pre-area | region) by carrying out the linear condensing of the near infrared rays to a laminated glass, and finally adds bending stress to the said cutting | disconnection scheduled area | region. Instead of putting a scribe line on the surface on the planned cutting line with a conventional carbide tool blade, it is merely a scribe line put by heating with near infrared light. This mechanical folding process causes the glass to come into contact with each other at the planned cutting line portion, so that small fragments called “chirico” are generated, and it is considered that the surface and cut surface of the cut glass are contaminated. In addition, innumerable minute scratches called “microcracks” are generated on the cut surface, and the mechanical strength of the cut glass may be lowered.

JP 2005-314198 A Japanese Patent No. 4179314 JP 2009-84133 A JP-A-2005-112683

  As mentioned above, mechanical cutting methods generate small fragments called `` Kirico '' when breaking, or microcracks, `` sedges '', `` corners '', `` cut edges '', `` There are cases where cut defects such as “scratch” and “escape” as described in JIS R3202 may occur, and the mechanical strength of the cut material is reduced.

  Moreover, in the case of the cutting method using the laser described above, according to Patent Document 2, the laser output required for cutting the 2.8 mm non-alkali glass is 200 W, but when the thickness of the plate glass is increased, it is higher than 200 W. An output laser is required, and it is technically difficult to prepare such a laser.

  Therefore, in view of the above problems, the present invention provides an apparatus and method that can cut a full body of a glass sheet from a thin plate to a thick plate in a non-contact manner with the glass plate without damaging the surface on the planned cutting line. Objective.

  In the process of studying heat treatment of a plate glass by a near-infrared line heater that emits light in a wavelength band that passes through the plate glass to some extent and is easy to increase the output compared to a laser, the light of the near-infrared line heater is We have found a method that has never been reported so far that a glass plate can be cut without a break by condensing it in a line shape on the planned cutting line from edge to edge.

  When the near-infrared light condensed as described above is irradiated in a line shape on the planned cutting line from edge to edge of the plate glass, the plate glass absorbs the infrared light in a line shape on the glass surface on the planned cutting line of the plate glass. At the same time, heat radiation from the glass surface causes a temperature gradient on the glass surface. Moreover, by condensing infrared light and increasing the energy of obliquely incident light, the temperature at a predetermined distance from the cutting line on the back surface of the glass rises, and a temperature gradient is generated on the back surface of the glass. Due to these temperature gradients, tensile stress is generated on the glass edge on the surface of the plate glass and the back side of the plate glass on the planned cutting line, and even for thick plate glass used in construction applications, the plate glass is divided by full body cutting. Obtaining the knowledge that this is possible, the present invention has been achieved.

  That is, the present invention is an apparatus for cutting a sheet glass, an infrared light source, a light collecting apparatus that condenses the infrared light emitted from the infrared light source in a line shape along a planned cutting line from the edge of the plate glass to the edge, A plate glass cutting device comprising: a mounting table for mounting the plate glass; and a lifting device capable of adjusting a distance between the infrared light source and the plate glass, and cutting the plate glass by irradiation with the infrared light. is there.

  The plate glass cutting device according to the present invention irradiates condensed infrared light in a line shape on the planned cutting line of the plate glass, and then the plate glass is cut without breaking if the irradiation is continued until the plate glass is cut. . When the cutting device of the present invention is used, a surface parallel to the thickness direction of the plate glass among the surfaces having the planned cutting line becomes a cut surface after cutting.

  Cutting is performed along the planned cutting line from edge to edge described above. In the present specification, the planned cutting line refers to a line for cutting the glass surface. However, “on the planned cutting line” means that the surface having the planned cutting line exists in a plane parallel to the thickness direction of the plate glass, and does not indicate the above-mentioned “up” or “down” direction. . Further, the “surface parallel to the thickness direction of the plate glass” becomes a cut surface after cutting.

  In the present invention, “cutting the glass sheet in a non-contact manner with the glass plate” means, for example, an external force excluding heating, such as a break, in which an apparatus or a human hand is brought into contact with the plate glass to cut it. It means not to cut by artificial addition. As described above, the cutting apparatus of the present invention can divide a plate glass by full body cutting only by irradiation with infrared light collected in a line shape.

  The “full body cutting” of the present invention refers to dividing an object into two parts. In addition, “two divisions” refers to dividing a single scheduled cutting line into two.

  The said condensing device installs an infrared light source in the position which can condense in a line form. For example, when the infrared light source is an infrared lamp and the light is condensed using a concave mirror, the infrared light source is installed so that a desired position can be focused. At this time, an infrared lamp is installed above the plate glass so that the glass surface of the plate glass can be irradiated with infrared light, and the concave mirror is placed above the infrared lamp so that the infrared lamp can be condensed. Install.

The lifting device can lift and lower the infrared light source, or lift and lower the plate glass,
You may raise and lower both. Further, the elevating device may be provided along with the light collecting device.

  The sheet glass cutting device of the present invention can be used for a sheet glass having a thickness of 2 mm or more and 25 mm or less used as a general architectural sheet glass (for example, a sheet glass described in JIS R3202), but is limited in principle to the above thickness. It is not a thing.

  Infrared light sources are more effective especially for building glass plates (transmittance at 780-2500 nm is about 30-85%) by setting the peak wavelength of infrared light in the near infrared (780-2500 nm) region. It is possible to cut in a short time. That is, the infrared light source preferably has a peak wavelength of the infrared light in the near infrared region.

  Although the principle of full-body cutting of sheet glass in a non-contact manner by the sheet glass cutting apparatus of the present invention has not been fully clarified, a temperature gradient is generated in the sheet glass by collecting and irradiating infrared light, and tensile stress is caused by the temperature gradient. It is presumed that full body cutting occurs. The principle will be described below with reference to FIG.

  FIG. 1 (a) shows a schematic diagram showing a state of condensing and irradiating infrared light onto the surface of the plate glass 1 before cutting, and FIG. 1 (b) shows a schematic diagram showing a state of heat radiation from the surface of the plate glass 1 before cutting. It was. First, when the infrared light source is condensed and irradiated in a line shape on the II ′ plane along the planned cutting line 3, the infrared light 9 is absorbed on the planned cutting line 3. Next, since the surface of the plate glass 1 on the planned cutting line 3 comes into contact with the atmosphere, the heat once absorbed is partially dissipated into the atmosphere. In addition, when the light is condensed and irradiated in a line shape, the temperature distribution on the irradiated surface is highest at the center of the line, and gradually decreases at both ends of the line, and heat is also generated from the side surface from the glass edge 7 of the plate glass 1, Furthermore, the temperature decreases.

  Next, infrared light that has not been absorbed or reflected by the surface of the plate glass 1 penetrates into the glass as transmitted light, and the penetrated infrared light travels in the thickness direction of the plate glass 1 around the planned cutting line 3. . A part of the infrared light is absorbed by the glass sheet 1, and the temperature rises when absorption occurs. On the other hand, infrared light that is not absorbed continues to travel through the glass sheet. The infrared light is absorbed by the glass as it goes away from the focal point, and the amount of energy per unit area becomes smaller. Therefore, the temperature rise of the plate glass becomes smaller as it goes away from the focal point. In addition, the light incident obliquely into the glass is infrared light collected by a condensing device, and the amount of energy is larger than that of light traveling straight into the glass. Therefore, the temperature of the traveling direction of the oblique incident light is likely to increase. It becomes higher than the temperature near the back surface of the plate glass on the planned cutting line.

  Infrared light travels through the plate glass and raises the temperature in the plate glass, so that a temperature gradient occurs on the plate glass surface and inside the plate glass. A temperature gradient on the surface of the plate glass 1 will be described with reference to a schematic cross-sectional view showing a temperature gradient on the II ′ plane immediately before cutting shown in FIG. As described above, the surface of the plate glass 1 has the highest central portion of the condensed line, and gradually becomes lower at both ends of the line, and heat is also emitted from the side of the glass edge 7 of the plate glass 1. The temperature of the edge 7 is lowest.

  Further, the temperature gradient inside the plate glass will be described with reference to a schematic cross-sectional view showing the temperature gradient of the II-II ′ plane immediately before cutting shown in FIG. Since the temperature in the vicinity of the surface of the plate glass 1 is lowered by heat radiation to the air, the temperature at a position slightly separated from the surface on the planned cutting line to the inside of the plate glass is the highest. Further, since the oblique incident light obliquely incident on the plate glass has a large amount of energy, the temperature in the traveling direction of the oblique incident light is remarkably increased. On the other hand, since the temperature rise in the vicinity of the back surface on the planned cutting line is small, the temperature gradient in the vicinity of the back surface of the plate glass is such that the temperature at a position spaced apart by a predetermined distance is high, centering on the low temperature portion.

  Moreover, when the above temperature gradient arises, it will be in the state in which the tensile stress and the compressive stress were produced on the plate glass surface and plate glass inside. Generally, the stress generated in the plate glass includes a tensile stress and a compressive stress. Usually, the glass is broken by the generation of the tensile stress. Compressive stress is generated in the high temperature portion where the glass temperature is high, and the periphery of the high temperature portion is pulled, and particularly strong tensile stress is generated in the low temperature portion where the glass temperature is low. On the surface of the plate glass, the glass edge is pulled toward the center of the line, and a strong tensile stress is generated on the glass edge. Further, inside the glass, as shown in FIG. 1 (d), a tensile stress is generated near the back surface on the planned cutting line 3 in a direction away from the vertical line with the vertical line of the planned cutting line 3 as the center. It becomes a state.

  Next, a crack occurs in the glass edge of the plate glass in a state where tensile stress is generated, and the crack propagates to the back surface on the planned cutting line where the tensile stress is generated, and proceeds on the planned cutting line, It leads to full body cutting. In general, when the mechanical strength between the in-plane and the edge portion of the plate glass is compared, the glass edge is weaker, so that the glass edge of the planned cutting line is the starting point and cracks are generated in the plate glass. In addition, although there are two glass edges on the planned cutting line, of the two points, the one with the lower mechanical strength is the starting point.

  It is considered that the full body can be cut without contact with the glass plate by the above-described action.

  According to the present invention, it is possible to divide a plate glass, particularly a thick plate glass, by full body cutting without contact with the plate glass without damaging the surface on the cutting line. The cutting device of the present invention can perform accurate cutting in a short time with a simple operation by adjusting the output and position of the infrared light source. Further, according to the present invention, there is no occurrence of “microcracks” on the glass edge because the glass does not touch each other when cutting the glass without forming a scribe on the planned cutting line. It became possible to suppress a decrease in strength. In addition, according to the present invention, since no cullet is generated by cutting, it is possible to eliminate the adhesion of “silico” to the cut surface and the glass surface. In addition, according to the present invention, it is possible to obtain a cut surface having no cut defect (“bending”, “corner”, “cutting edge”, “scratch”, “escape”, etc.).

(A) Schematic diagram showing the state of condensing and irradiating infrared light onto the surface of the plate glass before cutting, (b) Schematic diagram showing the state of heat dissipation from the surface of the plate glass before cutting, (c) I- just before cutting It is a cross-sectional schematic diagram showing the temperature gradient of I 'surface, (d) The cross-sectional schematic diagram showing the temperature gradient of II-II' surface just before cut | disconnecting. It is a schematic diagram when the cutting apparatus of the plate glass of this invention is seen from the angle orthogonal to the surface which has a cutting projected line. It is a schematic diagram when the plate glass cutting device of the present invention is viewed from an extension line of a planned cutting line. It is the schematic diagram which showed an example of the temperature distribution of the line width direction (X direction) and the line length direction (Y direction) in the focus of the infrared light at the time of heating a board | substrate with an infrared line heater. It is a drawing substitute optical photograph of the plate glass cut | disconnected in the Example. It is a drawing substitute optical photograph of the cut surface of the plate glass cut | disconnected in the Example. It is a drawing-substituting optical photograph of the plate glass (left) which was folded by a conventional break and the plate glass (right) cut in the examples. It is a drawing substitute optical photograph at the time of observing the plate glass (left) which carried out the break by the conventional break, and the plate glass (right) cut | disconnected in the Example using an optical microscope.

  The present invention is an apparatus for cutting a plate glass, and includes an infrared light source, a light collecting device for collecting infrared light emitted from the infrared light source in a line shape along a planned cutting line from the edge of the plate glass to the edge, and the plate glass A plate glass cutting device comprising: a mounting table on which a glass plate is mounted; and a lifting device capable of adjusting a distance between the infrared light source and the plate glass, and cutting the plate glass by irradiation with the infrared light.

1. Hereinafter, the cutting device of the present invention will be described in more detail.

  Examples of the infrared light source used in the cutting apparatus of the present invention include a near-infrared line heater, a mid-infrared line heater, and a far-infrared line heater. In particular, soda-lime silicate glass, which is a plate glass used in construction, has high infrared transmission and absorption in the near-infrared line heater wavelength band, and absorbs infrared light in the thickness direction of the plate glass, as described above. Therefore, it can be preferably used. When using a near infrared line heater for cutting soda lime silicate glass as described above, it becomes possible to form a suitable temperature distribution in the range of the plate width in the whole plate thickness direction, and good cutting without cut defects You can get a plane.

  The various line heaters described above generally have lamp portions that emit light of each wavelength, and the lamp portions are preferably installed so as to be parallel to the planned cutting line.

  In addition, the length of the above line heater can be cut without any problem if it is longer than the length from the edge of the plate glass to the edge, but the length of the line heater may be slightly shorter than the length from the edge of the plate glass to the edge. It was found that it was cuttable. That is, in the present invention, the infrared lamp is an infrared line heater, and the length of the infrared line heater is preferably 90% or more with respect to the length from the edge of the plate glass to the edge.

  Moreover, when the length of a cutting planned line is longer than the said line heater, it is also possible to cut | disconnect a some line heater side by side. At this time, if the distance between the line heater and the line heater is wide, a good cut surface may not be obtained. Therefore, it is desirable to make the distance as narrow as possible. That is, it is preferable to install two or more infrared light sources and two or more condensing devices so that two or more infrared lights condensed in a line overlap or contact each other.

  The condensing device used in the cutting device of the present invention is preferably a concave mirror because it can condense infrared light efficiently. That is, in the cutting device of the present invention, the light collecting device is formed of a concave mirror, has an infrared light source in a direction perpendicular to the glass surface of the plate glass so as to be parallel to the planned cutting line, and has a line shape on the infrared light source. It is preferable to have the concave mirror capable of condensing light.

  In addition, various lenses such as a cylindrical lens may be used as the light collecting device. When using a cylindrical lens, it is installed between the infrared light source and the plate glass.

  When condensing the infrared light source using the above-described condensing device, it is preferable to narrow the condensing width at the focal point in order to increase the accuracy of full body cutting. The light collection width depends on the light collecting device. In the examples of the present specification, cutting was performed with a light collection width of 3 mm.

  Moreover, in order to raise the efficiency of condensing, you may form an infrared rays absorption layer on the cutting projected line of the plate glass surface. The infrared absorbing layer is preferably less than or equal to the width of the light collection width. For example, it is easy to draw a line with a black pen or the like.

  In the cutting apparatus of the present invention, the mounting table is not particularly limited as long as a plate glass can be installed. Further, since the mounting table is exposed to infrared light, it is preferable to use a heat-resistant member. Further, a heat insulating material such as glass wool may be provided on the surface in contact with the plate glass, and the plate glass may be contacted via the heat insulating material. By installing the heat insulating material, direct heating of the mounting table by infrared rays can be prevented, which helps protect the mounting table. Further, the mounting table may be a lifting table having a lifting device.

  In addition, in this specification, the mounting table side of plate glass is described as lower and the plate glass side is described as upper. Since it is easy to protect the infrared light source from dust or the like, the infrared light source is preferably installed on the upper side of the plate glass. It is also possible to provide an infrared light source under the mounting table. As one plan of the embodiment, an infrared light source and a light collecting device are provided on the lower side of the mounting table, and a linear slit or the like is provided on the mounting table so that the collected infrared rays reach the surface of the plate glass. Can be considered. Since the surface of the placed plate glass is exposed at the slit portion, the plate glass can be cut by aligning the planned cutting line with the slit portion.

  Further, as described above, the cutting device of the present invention enables the division of the plate glass only by the irradiation of the condensed infrared light. Since this division is due to a strong tensile stress generated on the planned cutting line, in some cases, the divided plate glass may slide on the mounting table so as to separate the cut surfaces. In such a case, depending on the size of the mounting table, the divided plate glass may fall below the mounting table. Therefore, an auxiliary member for preventing the fall may be installed in advance. The auxiliary member may be installed on the mounting table or may be installed separately from the mounting table as long as it can prevent the plate glass from falling. Moreover, even if this auxiliary member is contacting the plate glass before cutting | disconnection, it may install so that it may contact when the divided plate glass slides the mounting base.

2. Next, a method for cutting plate glass using the cutting apparatus of the present invention will be described in more detail.

  In the sheet glass cutting device of the present invention, after irradiating the condensed infrared light onto the planned cutting line of the sheet glass, if the irradiation is continued until the sheet glass is cut, the sheet glass is cut without breaking.

  As described above, since the cutting apparatus of the present invention performs full body cutting using tensile stress, the planned cutting line is preferably not complicated, and more preferably, for example, a straight line.

  The above-mentioned "until the plate glass is cut" refers to until the plate glass is divided. However, even if irradiation continues after the plate glass is divided, it does not cause a defect on the cut surface of the plate glass.

  The plate glass to be cut is not particularly limited as long as it is a glass that absorbs infrared light, and examples thereof include soda lime glass, quartz glass, borosilicate glass, and aluminosilicate glass.

  Irradiation with infrared light is performed so that the heated portion has a temperature lower than the softening point of the plate glass. When the glass reaches the softening point, the glass may flow, and the glass surface may become rough or warp after cutting. For example, in the case of soda lime glass used for general architectural glass, the softening point is about 720 to 730 ° C.

  In addition, it is desirable to use a line heater as the infrared light source, and it is desirable that the length of the infrared light source can be heated at least on the planned cutting line excluding the glass edge. If the infrared light source is too short, cracks may bend at portions where heating is insufficient, and cut-off defects may occur. In order to reduce the possibility of occurrence of such a defect, the length is preferably equal to or longer than the length of the planned cutting line from edge to edge. Also, since the length of the line heater can be heated without a shortage even if it is slightly shorter than the length from the edge of the glass sheet, the length of the infrared line heater is from the edge of the glass sheet to the edge. It is preferably 90% or more with respect to the length.

  The output during heating of the above line heater may be appropriately selected so that it can be cut. For example, in the examples of the present specification, heating was performed using a near-infrared line heater so that the value represented by line heater output (W) / line heater length (cm) was 100 W / cm. . Moreover, in the said Example which condensed the said near-infrared line heater with the concave mirror, when three types of glass of 100 mm x 100 mm and thickness 8mm, 12mm, and 25mm was cut | disconnected, although it changes with thickness, it is 10 from the start of irradiation. The division of the plate glass was completed in ˜20 seconds.

  In the present invention, a glass edge on the cutting line of the plate glass is scratched only by the irradiation of the condensed infrared light, and starting from this, the scratch propagates to the surface of the plate glass and the inside of the plate glass, so that the plate glass is full body. Disconnected. At this time, since scratches are generated at the same time as the glass edges are scratched, the cutting of the glass sheet is started as soon as the scratches are generated. Although the division of the plate glass is completed by the completion of the cutting, the time taken from the generation of the glass edge to the completion of the division is a short time. For example, the plate glass having a size of 100 mm × 100 mm and a thickness of 25 mm according to the embodiment of the present specification. In this case, the cutting was completed almost instantaneously after the occurrence of the scratch, and it was less than 1 second.

  Further, in the present invention, the former is longer in the time from the start of irradiation of the condensed infrared light until the glass edge is damaged and the time from the generation of the glass edge scratch to the completion of the division. Become.

  Note that the above-mentioned “completion of division” can be confirmed visually, for example, because a cut surface is formed on the planned cutting line after the division.

  In the present invention, it is possible to shorten the time required for cutting the full body of the plate glass by efficiently scratching the glass edge. As a method of causing scratches on the glass edge in this manner, for example, in order to increase the temperature difference between the glass edge and the periphery of the glass edge, the temperature of the glass edge is lowered, or heating to the glass edge is reduced. Can be mentioned.

  In order to lower the temperature of the glass edge, a cooling device may be used. By cooling the heating part on the planned cutting line with the cooling device, the heated part of the glass surface of the planned cutting line is rapidly cooled, so the temperature difference from the inside of the planned cutting line in the plate thickness direction becomes large, and the cutting planned It is considered that a large tensile stress can be generated by the wire. For example, the occurrence of scratches on the glass edge can be promoted by spraying air or the like on the glass edge.

  In order to reduce the heating to the glass edge, it is conceivable to reduce the infrared light irradiated to the glass edge, and the length of the line heater is changed from the edge to the edge so that the infrared light does not hit the glass edge. The length of the cutting line is slightly shorter than the length of the cutting line, or the length of the light collecting device is slightly shorter than the length of the cutting line. By doing as mentioned above, since the heating to a glass edge decreases, it becomes possible to suppress the temperature rise of a glass edge.

  In addition to the above, a mask material that shields infrared light from the line heater may be installed in advance on the glass edge portion.

  2 and 3 are schematic views showing an embodiment of a sheet glass cutting device using infrared light according to the present invention.

  In the sheet glass cutting device according to the present embodiment, the heat insulating material 4 is stacked on the lifting platform 5, the plate glass 1 is further stacked on the heat insulating material 4, and the line glass 1 is directly above the planned cutting line 3. A concave mirror 6 is arranged on the heater-type infrared lamp 2 and the infrared lamp 2.

  In FIG. 2, the infrared lamp 2 having a lamp length longer than the planned cutting line 3 is used. By using such an infrared lamp, it is possible to heat the cutting line without shortage, and therefore it is possible to prevent the occurrence of a cut edge defect due to insufficient heating.

  Further, when cutting a sheet glass having a long width, the lamp length of the infrared lamp 2 may be a long one corresponding to the length of the planned cutting line, or a plurality of infrared lamps 2 are prepared and cut. Irradiation may be performed in series so as to correspond to the length of the planned line.

  The concave mirror 6 is processed into a shape that can be condensed into a line shape. In FIG. 2, the concave mirror 6 is longer than the infrared lamp 2. By using the concave mirror as described above, infrared light emitted from the infrared lamp can be condensed without waste.

  It is preferable to arrange the infrared lamp 2 and the concave mirror 6 so that the condensing line of the infrared lamp 2 and the planned cutting line 3 are parallel to each other. Further, the focal position of the condensing line is not particularly limited as long as the glass sheet 1 can be cut appropriately. However, in order to generate the cutting start point near the planned cutting line, the glass plate absorbs infrared rays, a temperature gradient, and the like. Considering this, it is more preferable to collect light on the front surface or the back surface of the glass plate.

  The focal point of the condensing line of the infrared lamp 2 may be adjusted by the elevator 5. In addition, an elevating mechanism may be provided on the infrared lamp 2 side to adjust the focus.

  In FIG. 3, a cover glass 8 that protects the infrared lamp 2 and the concave mirror 6 is provided on the surface of the infrared lamp 2. As described above, since the cutting of the plate glass 1 is performed by a strong tensile stress, the plate glass may slide on the mounting table when the plate glass is divided. At this time, if there is dust or glass waste on the mounting table, it may be struck by the plate glass and hit the infrared lamp 2 or the concave mirror 6 and be damaged. It is preferable to prevent such breakage by the cover glass 8. The material of the cover glass is not particularly limited as long as the infrared transmittance is high.

  FIG. 4 shows an example of temperature distribution in the line width direction (X direction) and the line length direction (Y direction) at the focal point of infrared light when the substrate is heated using an infrared line heater as shown in FIGS. Show. The X direction in the figure indicates the width direction of the line-shaped focal point (direction perpendicular to the line-shaped focal point), and the Y direction indicates the length direction of the line-shaped focal point (direction parallel to the line-shaped focal point). Show. The data is a value obtained using a black body that does not reflect light. The line heater has the highest temperature in the central part of the focal line in both the X and Y directions, the peak temperature reaches about 1200 ° C, and the temperature gradually decreases as it spreads to both ends of the line, showing a large temperature gradient. It can be seen that the substrate can be heated.

  When the glass plate is heated by the line heater as described above, it is presumed that the temperature gradient generated in the plate glass 1 immediately before cutting becomes as shown in (c) and (d) of FIG. FIG. 1C shows a II-II ′ cut surface of the plate glass 1, and FIG. 1D shows a II-II ′ cut surface of the plate glass 1. FIGS. 1C and 1D are both expected diagrams, and the generated temperature gradient is not limited to this.

  The place where the maximum temperature is reached in the glass sheet 1 is a place where it enters a little from the surface of the glass sheet 1, and a gentle temperature is formed in the depth direction of the glass sheet 1 on the II ′ plane shown in FIG. A gradient is expected to form. On the other hand, in the II-II ′ plane shown in FIG. 1 (d), the temperature of the portion slightly inside from the surface of the plate glass 1 becomes the highest as in the II ′ plane. Further, the oblique incident light traveling inside the glass with the focal point of the infrared light 9 as the apex moves away from the line to be cut, but the temperature of the glass rises with the progress of the shielding incident light, as shown in FIG. As shown, the temperature on the planned cutting line 3 is lowest on the back surface of the plate glass 1.

  When the temperature gradient as described above occurs, a tensile stress layer in which a tensile stress is generated is generated on the glass edge 7 and the back surface of the glass sheet, and a compressive stress is applied to a high temperature portion in the glass sheet so as to balance the tensile stress. The generated compressive stress layer is generated. The tensile stress layer on the glass edge 7 or the back side of the plate glass is local, while the compressive stress layer inside the plate glass is wider than the above-described tensile stress layer. Corresponding tensile stress layers and compressive stress layers tend to increase in stress as the range is local. As a result, it is considered that tensile stress is greater than compressive stress.

  Examples of the present invention are shown below.

Example 1
First, a near-infrared type line heater (manufactured by Highbeck Co., Ltd., line heater HYL25-12) in which an infrared lamp and a concave mirror are arranged in advance was installed so as to be parallel to the glass mounting surface of the lifting platform. The length of the line heater used was 12 cm.

  The plate glass used for cutting was 100 mm × 100 mm, and had three types of thicknesses of 8 mm, 12 mm, and 25 mm.

  Next, a plate glass (soda lime glass) was placed on the lifting platform, and the lifting platform was operated to focus on the surface of the plate glass. In this example, the distance between the cover glass surface of the infrared lamp and the plate glass surface was 25 mm.

  Next, when a near-infrared type line heater was irradiated at 1200 W for 20 seconds on a cutting planned line having a central length of 100 mm for dividing the plate glass into 20 seconds, the thickness was 8 mm for 12 seconds, the thickness was 12 mm for 19 seconds, and the thickness was 25 mm. When 15 seconds passed, the plate glass was divided. Further, at this time, after the glass edge was scratched, the full body was instantaneously cut, and the plate glass of any thickness was less than 1 second.

  Also, a photograph of a 25 mm plate glass cut into two parts is shown in FIG. 5, a photograph of the cut surface is shown in FIG. 6, a conventional plate glass (left) that has been folded by a conventional break, and a plate glass obtained in this example. A photograph of the (right) corner is shown in FIG. As shown in FIG. 5 to FIG. 7, a clean cut surface obtained by cutting with a sharp blade that does not cause micro cracks or cut defects on the cut surface was obtained. Moreover, the same cut surface was obtained also for the other plate glass.

  Moreover, although the ridgeline of the cut surface by this method was sharp, even if the ridgeline was traced with a finger, the finger was not cut. This is because there is no generation of microcracks on the cut surface, and no fine irregularities of glass are formed on the ridgeline.

  In addition, the white line of the left-right direction which can be seen on the cut surface of FIG.

Example 2
Near infrared line heater (line heater HYL25-28, manufactured by Highbeck Co., Ltd.) whose length of the line heater is 28 cm, and 250 mm × 300 mm (the length to be cut is 300 mm) as a plate glass for cutting, Three types of thicknesses of 8 mm, 15 mm, and 25 mm were prepared. The plate glass was cut in the same manner as in Example 1 except that the cutting target line having a central length of 300 mm for dividing the plate glass was irradiated with a near infrared line heater at 1960 W until the cutting was completed. . In this example, since the length of the planned cutting line on the plate glass is longer than the length of the line heater, the distance from the glass edge on the planned cutting line to the end of the line heater is the same on the left and right.

  When the time required for cutting was 23 seconds at a thickness of 8 mm, 19 seconds at a thickness of 15 mm, and 38 seconds at a thickness of 25 mm, the plate glass was divided. Further, at this time, after the glass edge was scratched, the full body was instantaneously cut, and the plate glass of any thickness was less than 1 second.

  The cut surface of 25 mm plate glass was observed with the optical microscope among the obtained plate glasses. FIG. 8 shows photographs of the plate glass surfaces of the conventional plate glass (left) and the plate glass (right) obtained in this example, which were folded by a conventional break. As shown in FIG. 8, the conventional product shows microcracks due to cutter scratches on the glass surface, but this method product does not produce microcracks or cut-off defects, and has a clean cut surface as if cut with a sharp blade. It was. The same applies to other glass plates.

Example 3
Two infrared line heaters (line heater HYL25-28N, manufactured by Highbeck Co., Ltd.) having a line heater length of 28 cm were connected in series, and the distance between the line heaters was set to 20 mm. Three types of plate glass having a thickness of 8 mm, 15 mm, and 25 mm were prepared as a plate glass for cutting at 400 mm × 600 mm (length to be cut is 600 mm). The plate glass is cut in the same manner as in Example 1 except that the center cutting line of 600 mm length for dividing the plate glass is irradiated with an infrared line heater at 1960 W until the cutting is completed. It was. The two infrared lights collected at this time seemed to have no gap between the two infrared lights.

  The time required for cutting was 30 seconds at a thickness of 8 mm, 40 seconds at a thickness of 15 mm, and 60 seconds at a thickness of 25 mm, and the plate glass was divided, and the influence of the connecting portion connecting two infrared line heaters was not observed. Further, at this time, after the glass edge was scratched, the full body was instantaneously cut, and the plate glass of any thickness was less than 1 second.

  From the above, the glass glass cutting device and the cutting method of the present invention do not form scribes on the planned cutting line, and the glass does not touch each other when cutting the glass. It is possible to suppress a decrease in edge strength.

  In addition, in the cutting method using the cutting device of the present invention, no cullet is generated, and thus it is possible to eliminate the adhesion of “silico” to the cut surface and the glass surface.

  In addition, the cutting device of the present invention makes it possible to obtain a cut surface having no cut defects (such as “bald”, “corner”, “cut edge”, “scratch”, “escape”).

DESCRIPTION OF SYMBOLS 1 Sheet glass 2 Infrared lamp 3 Planned cutting line 4 Heat insulating material 5 Lifting stand 6 Concave mirror 7 Glass edge 8 Cover glass 9 Condensed infrared light

Claims (6)

An apparatus for cutting a plate glass having a thickness of 2 mm or more and 25 mm or less,
Infrared light source, condensing device that irradiates the glass surface with the infrared light emitted from the infrared light source, condensing in a line along the planned cutting line from the edge of the plate glass to the edge,
A mounting table on which the plate glass is mounted, and an infrared light source capable of adjusting a distance between the infrared light source and the plate glass or a lifting device for the plate glass,
The infrared light source is an infrared line heater, and the length of the infrared line heater is shorter than the length from the edge of the plate glass to the edge;
In order not to directly irradiate the glass edge on the planned cutting line with the infrared light, by irradiating the infrared light on the planned cutting line, a scratch as a starting point is generated on the glass edge without breaking or cleaving. An apparatus for cutting a plate glass, wherein the plate glass is cut in a full body. The plate glass cutting device according to claim 1, wherein the light collecting device is a concave mirror. The length of the said infrared line heater is 90% or more with respect to the length from the edge of a plate glass to an edge, The cutting device of the plate glass of Claim 1 or 2 characterized by the above-mentioned. The plate glass cutting device according to any one of claims 1 to 3, wherein a peak wavelength of the infrared light is in a near infrared region. 5. The infrared light source and the two or more condensing devices are installed so that two or more infrared lights condensed in a line overlap or contact each other on one straight line. The flat glass cutting device of description. 6. A method for cutting a glass sheet, comprising cutting the glass sheet in full body in less than 1 second after the scratch at the glass edge using the cutting device according to claim 1 occurs.