Flattening evaluation method of cloth material

Abstract

To provide a method for evaluating a degree of unevenness of a mold cloth for evaluating an influence of a mold cloth on the quality of a glass plate.SOLUTION: A method for evaluating a degree of unevenness of the surface of a cloth material superposes a resin sheet onto the surface of the cloth material, brings the cloth material into contact with the resin sheet, and obtains a laminate, performs one method of (1) a reflection image evaluation method for projecting the surface of the resin sheet onto a screen by a projector, photographing the obtained reflection image by a camera and obtaining a monitor image, and image processing the monitor image, and (2) a stereoscopic optical image evaluation method for obtaining a stereoscopic optical image of the cloth material in the laminate, using a one-shot 3D measurement device, and thereby evaluates a degree of unevenness of the surface of the cloth material.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for evaluating the flattening of a cross member, and more particularly, to a method for evaluating the degree of unevenness on the surface of a mold cross used when bending a glass plate.

Background Art

[0002] In recent years, window glasses for automobiles and window glasses for buildings with curvature have been used to enhance aesthetic appearance, light transmittance efficiency, etc. A glass having a curved shape (bent glass) is manufactured, for example, by heating a glass plate to a temperature above the softening point in a heating furnace and pressing it with a mold having a predetermined shape.

[0003] In a bending apparatus used for press-bending a glass plate, in order to prevent the glass plate from being adsorbed to the mold, the surface of the mold is covered with a protective material called a mold cross. Since a woven fabric in which yarns (spun yarns) made of refractory fibers are generally woven is used for the mold cross, there are fine irregularities on its surface, and when the glass plate is pressed, the irregularities on the surface of the mold cross may be transferred to the surface of the glass plate. As a result, fine irregularities are generated on the surface of the glass plate, and a phenomenon called undulation (perspective distortion) may occur, such as the surface of the glass plate appearing wavy or the object appearing distorted depending on the viewing angle.

[0004] If the distortion that occurs when observing an object through a glass plate is too large, it will damage the appearance and also obstruct the view. Therefore, several methods have been proposed as methods for evaluating whether the perspective distortion of the glass plate is within an allowable range.

[0005] For example, a method has been proposed in which a photographed image by transmitted light passing through a glass plate is generated and the degree of perspective distortion of the glass plate is confirmed by evaluating this image (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0006] "[Patent Document 1]" Japanese Patent Application Laid-Open No. 11-142344 "[Patent Document 2]" Japanese Patent Application Laid-Open No. 11-211425 "[Summary of the Invention]" "[Problems to be Solved by the Invention]"

[0007] Conventionally, the glass plate has been directly evaluated, and a method for evaluating the superiority or inferiority of the mold cloth that affects the perspective distortion of the glass plate has not been established.

[0008] Therefore, an object of the present invention is to provide a method for evaluating the degree of unevenness of a mold cloth for evaluating the influence of the mold cloth on the quality of a glass plate. "[Means for Solving the Problems]"

[0009] The inventors of the present invention obtained a laminate by laying a resin sheet along the surface of the cross member, and confirmed the reflection image on the surface of the resin sheet, or confirmed the three-dimensional optical image of the cross member in the laminate with an optical microscope to evaluate the degree of unevenness on the surface of the cross member. As a result, it was found that the degree of perspective distortion of a glass plate produced using this cross member can be predicted and evaluated, and the present invention has been completed.

[0010] An aspect of the present invention is a method for evaluating the degree of unevenness on the surface of a cross member, which comprises overlaying a resin sheet on the surface of the cross member, bringing the cross member and the resin sheet into close contact with each other by vacuum to obtain a laminate, and evaluating the degree of unevenness on the surface of the cross member by performing any one of the following methods (1) and (2). The present invention relates to a method for evaluating the flatness of a cross member. (1) A reflection image evaluation method in which the surface of the resin sheet is projected onto a screen by a projector, the obtained reflection image is photographed by a camera to obtain a monitor image, and the monitor image is subjected to image processing (2) Using a one-shot 3D measuring instrument, obtain a three-dimensional optical image of the cross material in the laminate, a three-dimensional optical image evaluation method

Effect of the Invention

[0011] According to the method for evaluating the flattening of the cross material of the present invention, since the degree of unevenness on the surface of the cross material can be evaluated, the degree of perspective distortion of the glass plate when the glass plate is formed using the evaluated cross material can be predicted and evaluated. In addition, since a flattened cross material can be selected, the perspective distortion of the bent and formed glass plate can be reduced, and the formation of a glass plate that deviates from the standard can be avoided.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described, but the present invention is not limited by the examples in the following description. In this specification, "~" indicating a numerical range means including the numerical values described before and after it as the lower limit value and the upper limit value.

[0014] The method for evaluating the flattening of the cross material of the present invention is a method for evaluating the degree of unevenness on the surface of the cross material. A resin sheet is overlaid on the surface of the cross material, and the cross material and the resin sheet are adhered by vacuum to obtain a laminate. The degree of unevenness on the surface of the cross material is evaluated by performing any one of the following methods (1) and (2). (1) Project the surface of the resin sheet onto a screen using a projector, capture the resulting reflected image with a camera to obtain a monitor image, and perform image processing on the monitor image. A method for evaluating a reflected image (2) A method for evaluating a three-dimensional optical image, which uses a one-shot 3D measuring instrument to obtain a three-dimensional optical image of a cross member in a laminate

[0015] Examples of the uses of the cross member include a protective material (mold cross) used when bending a glass plate and a protective material (setter cross) used when placing a glass plate on top of a ceramic plate or the like and heating it. The method for evaluating the flatness of the cross member of the present invention is suitable for evaluating the mold cross in that it can predict and evaluate the surface characteristics of an object in contact with the cross member.

[0016] The mold cross is a woven fabric knitted from yarns (spun yarns) made of refractory fibers. Examples of the fibers forming the mold cross include fibers made of metals, ceramics (glass fibers), heat-resistant resins (such as polyparaphenylene terephthalamide and polybenzoxazole (PBO)), etc., and are produced by combining one or more of these. The surface of the mold cross has fine irregularities, and when the glass plate is pressed, the irregularities on the surface of the mold cross can be transferred to the surface of the glass plate. By evaluating the degree of irregularities on the surface of the mold cross by the evaluation method of the present invention, the degree of perspective distortion on the surface of the glass plate can be predicted and evaluated, and a more preferable mold cross can be selected.

[0017] In the method for evaluating the flatness of the cross member of the present invention, first, a resin sheet is overlaid on the surface of the cross member, and the cross member and the resin sheet are adhered to each other by a vacuum to obtain a laminate.

[0018] For example, when obtaining a laminate by vacuum using a glass plate or a metal plate, the irregularities on the surface of the cross member are compressed and correct evaluation cannot be performed. However, by using a resin sheet, the cross member and the resin sheet are adhered to each other by a vacuum, and irregularities are formed on the surface of the resin sheet along the irregularities on the surface of the cross member.

[0019] Examples of the material of the resin sheet include, for example, polyvinyl chloride (PVC), acrylic, polyethylene terephthalate (PET), polycarbonate, etc. The resin sheet is preferably made of at least one resin selected from the group consisting of these. Among them, polyvinyl chloride (PVC) and polyethylene terephthalate (PET) are preferred, and polyvinyl chloride (PVC), which is low-cost and soft and easy to conform to the unevenness on the surface of the cross material, is more preferred.

[0020] It is preferable to use a resin sheet having a film thickness in the range of 0.5 to 6 mm. When the film thickness is 0.5 mm or more, it has excellent handleability without breaking during vacuuming, and when it is 6 mm or less, the reproducibility of the unevenness on the surface of the cross material is good. The film thickness of the resin sheet is more preferably 2 mm or more, further preferably 2.5 mm or more, particularly preferably 3 mm or more, and more preferably 5 mm or less, further preferably 4 mm or less, and particularly preferably 3.5 mm or less.

[0021] The vacuum when adhering the cross material and the resin sheet can be performed by a known method. For example, vacuuming using a vacuum generating device can be mentioned. As the vacuum generating device, general known vacuum generating devices such as a vacuum cleaner, a vacuum pump, and a suction machine are used.

[0022] In this embodiment, for example, it is preferable to produce the following vacuum mold and use it to obtain a laminate. As shown in FIG. 1, with respect to a sample glass 41 formed into a 4000R spherical surface with a size of 50 cm × 50 cm, an iron plate 42 with a length of 50 cm, a width of 50 cm, and a thickness of 1 cm having a plurality of air suction holes around the outer peripheral portion and the in-plane central portion (20 cm × 20 cm) is installed in a vacuum generating device 43 so that the inclination angle is 25° to produce a small vacuum mold 40. A cross is pasted on the iron plate 42, a resin sheet is covered thereon, and suction is performed with a vacuum generating device 43 to obtain a laminate having a curved surface.

[0023] When the laminate is used by the method (1) described below, the laminate having the curved surface prepared above is used. When it is used by the method (2) described below, a flat laminate is prepared by closely adhering the cross material and the resin sheet without using the sample glass 41.

[0024] During vacuuming, there is no particular limitation as long as the resin sheet can be closely adhered along the surface of the cross material, but it is preferable to perform vacuuming at a vacuum pressure of -50 to -5 kPa. When the vacuum pressure is -5 kPa or less, the resin sheet can follow the unevenness on the surface of the cross material. The vacuum pressure is more preferably -10 kPa or less, further preferably -15 kPa or less, particularly preferably -25 kPa or less. Also, it is more preferably -45 kPa or more, further preferably -40 kPa or more, particularly preferably -35 kPa or more.

[0025] The laminate obtained by vacuuming is evaluated by any one of the following methods (1) and (2). (1) Reflection image evaluation method: Project the surface of the resin sheet onto a screen by a projector, photograph the obtained reflection image with a camera to obtain a monitor image, and perform image processing on the monitor image. (2) Stereo optical image evaluation method: Use a one-shot 3D measuring instrument to obtain a stereo optical image of the cross material in the laminate.

[0026] <(1) Reflection image evaluation method> In the method (1) above, for example, a method using "SCREENSCAN-Reflected Distortion" manufactured by ISRA VISION, which is a 3D measurement system capable of non-contact measurement of the curvature of the reflection surface of the cross material, can be mentioned. In the method (1) above, the maximum height difference Rz on the surface of the cross material can be measured.

[0027] The measurement of the maximum height difference Rz is performed as follows. First, using "SCREENSCAN - Reflected Distortion" manufactured by ISRA VISION, obtain a reflected image of the resin sheet surface of the laminate obtained above. Photograph the obtained reflected image with a camera to obtain a distribution image of 1 / R representing the strength of distortion. Decompose this distribution image into 256 color difference gradations, and from the light and shade distribution in the central part of 400 cm 2 (20 cm × 20 cm) region A, confirm the height difference between light and shade, and obtain the maximum value (maximum light and shade difference) of the height difference between light and shade as the maximum height difference Rz of the unevenness on the cross surface. Hereinafter, the method for evaluating the unevenness on the cross surface by this method is referred to as the "screen scan evaluation method".

[0028] More specifically, in the screen scan evaluation method, the laminate is set in the measurement mold "SCREENSCAN - Reflected Distortion" manufactured by ISRA VISION, a zebra image is projected onto the screen by a projector, and the reflected image is photographed with a camera installed above. When the projected reflected image is displaced from its original position, it represents "distortion". In this system, the value of the reciprocal 1 / R of the displaced distance is measured and made into a distribution image so that the strength of the distortion can be recognized. Then, the obtained distribution image is decomposed into 256 color difference gradations, and from the light and shade distribution in the central part of 400 cm 2 (20 cm × 20 cm) region A, confirm the height difference between light and shade, and obtain the maximum value of the height difference between light and shade (maximum light and shade difference).

[0029] Since the resin sheet follows the surface shape of the cross material, the maximum height difference Rz measured by the screen scan evaluation method is approximately equal to the maximum height difference Rz on the cross material surface. The maximum height difference Rz on the cross material surface measured by the screen scan evaluation method is preferably 0.30 (1 / m) or less. When the maximum height difference Rz is 0.30 (1 / m) or less, it can be evaluated that the surface of the cross material is flattened. The maximum height difference Rz on the cross material surface is more preferably 0.26 (1 / m) or less, and even more preferably 0.24 (1 / m) or less. Since the smaller the maximum height difference Rz, the smaller the roughness of the cross material surface, the lower limit value is not particularly limited.

[0030] <(2) Stereoscopic optical image evaluation method> In the method of (2) above, as a one-shot 3D measuring instrument that is an optical microscope, for example, the average roughness Ra of the surface of the cross material in the set area can be measured using the one-shot 3D measuring instrument "VR6000" manufactured by KEYENCE Corporation, which is commercially available. In the one-shot 3D measuring instrument, when a striped light pattern is irradiated on the sample surface, the thickness and shape of the striped pattern change depending on the shape of the material, and the change is detected to measure the surface average roughness Ra of the cross material. Hereinafter, the method for evaluating the unevenness of the cross surface using "VR6000" manufactured by KEYENCE Corporation is referred to as the "pattern light projection evaluation method".

[0031] The average roughness Ra of the cross material surface is preferably 80 μm or less. When the average roughness Ra is 80 μm or less, it can be evaluated that the surface of the cross material is flattened. The average roughness Ra of the cross material surface is more preferably 70 μm or less, further preferably 60 μm or less, and particularly preferably 50 μm or less. Since the smaller the average roughness Ra, the smaller the roughness of the cross surface, the lower limit value is not particularly limited.

[0032] By measuring the laminate in which the cross material and the resin sheet are adhered together by the method of (1) or (2) above, the degree of unevenness of the surface of the cross material can be confirmed and the degree of flattening can be evaluated. And, for example, when the cross material is a mold cross used when bending a glass plate, the degree of perspective distortion of the glass plate produced using the cross material can be predicted and evaluated, so that a more preferable mold cross can be selected.

Examples

[0033] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto. In the following description, the same components are used. Also, unless otherwise specified, "parts" and "%" represent "parts by mass" and "mass%". Examples 1 to 8 are examples.

[0034] (Maximum height difference Rz of the mold cross surface) The maximum height difference Rz of the mold cloth surface was measured by the screen scan evaluation method. As shown in Fig. 3, for a sample glass 41 formed on a 4000R spherical surface with a size of 50 cm × 50 cm, an iron plate 42 with a length of 50 cm, a width of 50 cm, and a thickness of 1 cm, having a plurality of air suction holes around the outer peripheral portion and the central portion (20 cm × 20 cm) in the plane, was installed on a vacuum cleaner (vacuum generator 43) at an inclination angle of 25° to fabricate a small vacuum mold 40. A mold cloth was pasted on the iron plate 42, and a vinyl sheet (polyvinyl chloride (PVC)) with a thickness of 3 mm was covered thereon, and suction was performed with a vacuum cleaner at a pressure of about -35 kPa to obtain a laminate having a curved surface. It was set in the measurement mold "SCREENSCAN - Reflected Distortion" manufactured by ISRA VISION. A zebra image was projected onto the screen by a projector, and the reflected image was photographed by a camera installed above to obtain a distribution image of 1 / R representing the strength of distortion. The obtained distribution image was decomposed into 256 color difference gradations, and the height difference of light and shade was confirmed from the light and shade distribution in the central portion of 400 cm 2 (20 cm × 20 cm) region A of the image, and the maximum value (maximum light and shade difference) of the height difference of light and shade was obtained.

[0035] (Average roughness Ra of the mold cloth surface) The average roughness Ra of the mold cloth surface was measured by the pattern light projection evaluation method. The small vacuum mold 40 having the configuration shown in Fig. 1 was used. Without using the sample glass 41, a flat laminate in which the cloth and the vinyl sheet were adhered was used to measure the average roughness Ra of the cloth surface using a one-shot 3D measuring instrument "VR6000" manufactured by Keyence Corporation.

[0036] (Maximum value MAX of perspective distortion of glass molded product) Using "LABSCAN" manufactured by ISRA - VISION, an image was obtained by imaging under the condition of Filter 4.5.0 and an attachment angle of 30 degrees, and the maximum value of perspective distortion in the central portion of the image was measured.

[0037] <Test Example 1: Examples 1 to 4> (Example 1) Commercially available mold cloth A was used. The maximum height difference Rz on the surface of mold cloth A was 0.502 (1 / m). A glass molded product was produced using a press device equipped with a female mold (lower mold) and a male mold (upper mold) for press-molding a glass plate. Mold cloth A was attached to the lower surface of the male mold, and the glass plate (soda lime glass) was heated to 640 to 660 °C for bending, and a spherical glass with a radius of curvature of 4000 mm was obtained.

[0038] (Example 2) The mold cloth A of Example 1 was installed in a roller press, a pressure-resistant auxiliary plate (SUS304, plate thickness 4 mm) was placed on the cloth, and a pressure of 0.6 MPa was applied from above the pressure-resistant auxiliary plate, and the roller was reciprocated 3 times for pressing to obtain a flattened mold cloth. The maximum height difference Rz on the surface of the flattened mold cloth was 0.325 (1 / m). Using the obtained flattened mold cloth, a glass molded product was produced in the same manner as in Example 1.

[0039] (Example 3) Commercially available mold cloth B was used. The maximum height difference Rz on the surface of mold cloth B was 0.439 (1 / m). Using mold cloth B, a glass molded product was produced in the same manner as in Example 1.

[0040] (Example 4) The mold cloth B of Example 3 was subjected to a pressing treatment in the same manner as in Example 2 to obtain a flattened mold cloth. The maximum height difference Rz on the surface of the flattened mold cloth was 0.298 (1 / m). Using the obtained flattened mold cloth, a glass molded product was produced in the same manner as in Example 1.

[0041] The glass molded products of Examples 1 to 4 were laminated into a laminated glass, and the maximum value MAX of the perspective distortion was measured. The results are shown in Table 1 and Figures 2 to 3.

[0042]

Table 1

[0043] Example 2 evaluated Mold Cross A that was pressed and flattened from the Mold Cross A used in Example 1. Comparing Example 1 and Example 2, the maximum height difference Rz of Example 2 was smaller. Similarly, comparing Example 3 and Example 4, the maximum height difference Rz of Example 4, which evaluated the flattened Mold Cross B, was smaller. From these results, it was found that the degree of surface unevenness of the cross material can be evaluated by the screen scan evaluation method.

[0044] <Test Example 2: Examples 5 to 8> (Example 5) Commercially available Mold Cross A was used. The maximum height difference Rz of the surface of Mold Cross A was 0.502 (1 / m). Also, the average roughness Ra of the surface of Mold Cross A was 92.3 (μm). A glass molded product was produced using a press device equipped with a female mold (lower mold) and a male mold (upper mold) for press-molding a glass plate. Mold Cross A was attached to the lower surface of the male mold, and a glass plate (soda lime glass) was heated to 640 to 660 °C and bent to obtain a spherical glass with a radius of curvature of 4000 mm. Note that Example 5 is the same as Example 1.

[0045] (Example 6) The Mold Cross A of Example 1 was installed in a cylinder press machine, a pressure-resistant auxiliary plate (SUS304, thickness 4 mm) was placed on the cross, and a pressure of 2.5 MPa was applied from above the pressure-resistant auxiliary plate and pressed to obtain a flattened mold cross. The maximum height difference Rz of the surface of the flattened mold cross was 0.286 (1 / m), and the average roughness Ra was 72.6 (μm). Using the obtained flattened mold cross, a glass molded product was produced in the same manner as in Example 5.

[0046] (Example 7) It was carried out in the same manner as in Example 6 except that a pressure of 4.75 MPa was applied and pressed. The maximum height difference Rz of the surface of the planarized mold cross produced in Example 7 was 0.243 (1 / m), and the average roughness Ra was 69.0 (μm). Using the obtained planarized mold cross, a glass molded article was produced in the same manner as in Example 5.

[0047] (Example 8) It was carried out in the same manner as in Example 6 except that pressing was performed under a pressure of 7 MPa. The maximum height difference Rz of the surface of the planarized mold cross produced in Example 8 was 0.231 (1 / m), and the average roughness Ra was 58.8 (μm). Using the obtained planarized mold cross, a glass molded article was produced in the same manner as in Example 5.

[0048] The glass molded articles of Examples 5 to 8 were laminated to form a laminated glass, and the maximum value MAX of the perspective distortion was measured. The results are shown in Table 2 and FIGS. 4 to 5.

[0049]

Table 2

[0050] Comparing Example 5 with Examples 6 to 8, in Examples 6 to 8 where the mold cross was planarized, the maximum height difference Rz was smaller and the surface average roughness Ra was also smaller than in Example 5, showing a similar tendency. From this result, it was found that both the screen scan evaluation method and the pattern light projection evaluation method can evaluate the degree of unevenness on the surface of the cross material.

[0051] As described above, the following matters are disclosed in this specification. <1>A method for evaluating the degree of unevenness on the surface of a cross material, A method for evaluating the planarization of a cross material, which comprises laminating a resin sheet on the surface of the cross material, obtaining a laminate by closely adhering the cross material and the resin sheet by vacuum, and evaluating the degree of unevenness on the surface of the cross material by performing any one of the following methods (1) and (2). (1) Project the surface of the resin sheet onto a screen using a projector, capture the resulting reflected image with a camera to obtain a monitor image, and perform image processing on the monitor image. A method for evaluating a reflected image (2) Use a one-shot 3D measuring instrument to obtain a three-dimensional optical image of the cross material in the laminate. A method for evaluating a three-dimensional optical image <2> The method for evaluating the flattening of the cross material according to <1>, wherein the resin sheet is a sheet made of at least one resin selected from the group consisting of polyvinyl chloride, acrylic, polyethylene terephthalate, and polycarbonate. <3> The method for evaluating the flattening of the cross material according to <2>, wherein the resin sheet is a sheet made of polyvinyl chloride. <4> The method for evaluating the flattening of the cross material according to any one of <1> to <3>, wherein the film thickness of the resin sheet is 0.5 to 6 mm. <5> Perform the vacuuming at a vacuum pressure of -50 to -5 kPa. The method for evaluating the flattening of the cross material according to any one of <1> to <4>. <6> Measure the maximum height difference Rz of the surface of the cross material by the method of (1), and measure the surface average roughness Ra of the cross material by the method of (2). The method for evaluating the flattening of the cross material according to any one of <1> to <5>.

Explanation of symbols

[0052] 40 Vacuum mold 41 Sample glass 42 Iron plate 43 Vacuum generator

Claims

1. A method for evaluating the degree of unevenness on the surface of a cross member, comprising: laying a resin sheet on the surface of the cross member, and using a vacuum to closely adhere the cross member and the resin sheet to obtain a laminate, and evaluating the degree of unevenness on the surface of the cross member by performing any one of the following methods (1) and (2). A method for evaluating the flatness of a cross member. (1) Projecting the surface of the resin sheet onto a screen by a projector, photographing the obtained reflected image with a camera to obtain a monitor image, and performing image processing on the monitor image. A reflected image evaluation method (2) Using a one-shot 3D measuring instrument to obtain a three-dimensional optical image of the cross member in the laminate. A three-dimensional optical image evaluation method

2. The method for evaluating the flatness of a cross member according to Claim 1, wherein the resin sheet is made of at least one resin selected from the group consisting of polyvinyl chloride, acrylic, polyethylene terephthalate, and polycarbonate.

3. The method for evaluating the flatness of a cross member according to Claim 2, wherein the resin sheet is a sheet made of polyvinyl chloride.

4. The method for evaluating the flatness of a cross member according to Claim 1 or 2, wherein the film thickness of the resin sheet is 0.5 to 6 mm.

5. The method for evaluating the flatness of a cross member according to Claim 1 or 2, wherein the vacuum is performed at a vacuum pressure of -50 to -5 kPa.

6. The method for evaluating the flatness of a cross member according to Claim 1 or 2, wherein the maximum height difference Rz on the surface of the cross member is measured by the method of (1), and the surface average roughness Ra of the cross member is measured by the method of (2).

Images