JP2005053754A - Method of forming glass material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming a glass material by which the glass material is formed to have a small cross section similar to that of the glass material while keeping the surface state of the glass material. <P>SOLUTION: A preform before re-draw forming is shown by 10 in the figure, the cross section of the preform 10 has a cross sectional shape similar to a desired shape and the one end part of the preform 10 is fixed to a preform folder 20. The preform 10 is heated to have the viscosity ranging 10<SP>6</SP>-10<SP>8</SP>poise by a heater 30 arranged in a path of the preform 10 with the downward movement of the preform folder 20 in the vertical direction and further is pulled by a pulling roller 40 provided at a lower position to be formed into a small material 11 having cross section similar to that of the preform 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a glass material molding method, and more specifically to a glass material molding method for molding a glass material into a small cross section.

  In recent years, there has been a remarkable spread of liquid crystal display devices, but as one means for improving luminance (brightness), which is an important quality of liquid crystal display devices, high efficiency of the backlight can be mentioned. In the backlight, a discharge gas containing Xe or the like is enclosed in a glass tube coated with a phosphor material. A discharge is generated in the glass tube, and this discharge collides with Xe in the discharge gas and emits ultraviolet rays. The emitted ultraviolet light is an illuminating device that emits light when excited by visible light by a phosphor material. As the glass tube for the backlight, a glass tube having a small outer diameter is used in order to make the backlight thin.

  There is also known a display device that displays an image by arranging a plurality of gas discharge tubes in parallel. As the gas discharge tube for the display device, a glass tube having a diameter of about 0.5 to 5.0 mm is used (for example, see Patent Document 1).

By the way, there is a redraw molding method as one method of forming a glass tube, and it is widely known as a method of forming a glass tube (base material) having a large cross section into a small glass tube (for example, see Patent Document 2). . The redraw molding method uses a standard tube or a processed standard tube as a base material, and fixes one end of the base material to a base material holder and heats it sequentially from the other end with a heater. The glass tube is stretched in the long axis direction of the base material by using a pulling roller and formed into a glass tube having a smaller cross section.
JP 2003-86141 A JP 2003-92059 A

  However, in the conventional redraw molding method, if the heating temperature is too low, the glass becomes highly viscous, making continuous uniform molding difficult, and in some cases, the glass tube is torn, and conversely if the heating temperature is too high, the viscosity becomes low, There is a problem that irregular deformation of the glass tube occurs in the heated region, the surface state and shape of the base material cannot be maintained, and a glass tube having a similar shape cannot be obtained.

  Moreover, the brightness of the backlight can be further improved by forming the cross-sectional shape of the glass tube into a quadrangle, ellipse, etc. instead of the conventional circular shape. However, in the conventional redraw molding method, the cross-sectional shape is square. It has been difficult to form an elliptical glass tube with high accuracy and low cost.

As a result of redraw molding a glass tube under various temperature conditions and examining the shape of the molded glass tube, the inventors have found that irregular deformation occurs in a region where the viscosity of the glass tube is lower than 10 ⁶ poise. In a region where the glass tube cannot be formed into a completely similar shape and the viscosity of the glass tube is higher than 10 ⁸ poise, the glass tube is too hard to be stretched, but the viscosity of the glass tube is 10 ⁶ to It was found that by heating to a region exhibiting 10 ⁸ poise and controlling the pulling speed, a glass tube having a completely similar shape can be formed while maintaining the surface state.

The present invention has been made in view of such circumstances, and while maintaining the surface state of the glass material by heating the glass material and performing redraw molding in a region where the viscosity is 10 ⁶ to 10 ⁸ poise, An object of the present invention is to provide a method for forming a glass material that can be formed into a small cross section having a shape similar to that of a glass material.

In addition, the present invention is not limited to a circular cross section, and a glass material is previously formed into a shape similar to a desired shape, and the formed glass material is heated to redraw in a region where the viscosity is 10 ⁶ to 10 ⁸ poise. Thus, an object of the present invention is to provide a method for forming a glass material that can be formed into a desired shape while maintaining the surface state of the glass material.

Another object of the present invention is to provide a glass material molding method capable of spiraling a crow material by redrawing it in a region where the viscosity is 10 ⁶ to 10 ⁸ poise while rotating the glass material. And

The glass material molding method according to the first aspect of the present invention is a method of heating a glass material by a redraw molding method, heating the glass material to a predetermined viscosity, and controlling the pulling speed of the glass material, In the method for forming a glass material, the predetermined viscosity is 10 ⁶ to 10 ⁸ poise.

In the method for molding a glass material according to the first invention, the glass material is heated to a region where the viscosity exhibits 10 ⁶ to 10 ⁸ poise, and the glass material is stretched in the region. By stretching the glass material in this region, a glass material having a small cross section with excellent uniformity is formed with high accuracy and low cost.

  A glass material molding method according to a second invention is the glass material according to the first invention, wherein the glass material is previously molded into a cross-sectional shape similar to a desired shape, and the molded glass material is molded into a desired shape by a redraw molding method. It is characterized by.

In the method for molding a glass material according to the second invention, first, the glass material is previously molded into a cross-sectional shape similar to the desired shape, and then the viscosity of the molded glass material is 10 ⁶ to 10 ^8. It heats to the area | region used as a poise, stretches a glass material in this area | region, and shape | molds it in the similar shape which inherits a surface state. Thereby, since the glass material before redraw molding has a large cross section, it is easy to form (process). Therefore, the glass material may be processed into a shape similar to a desired shape before redraw molding.

  The glass material molding method according to a third aspect of the present invention is the glass material according to the second aspect, wherein the glass material is a tubular glass tube, the step of heating the both ends of the glass tube to enclose the gas, and enclosing the gas A step of disposing the glass tube in a mold whose inner surface is processed into a desired shape; and a step of heating to a glass softening point under a pressure lower than the internal pressure of the glass tube, the glass tube being a mold It shape | molds previously in the shape of the inner surface of this.

  In the glass material molding method according to the third aspect of the invention, when the glass material is a tubular glass tube, both ends of the glass tube are heated to enclose the gas therein, Is placed in a mold processed into a desired shape and heated to the softening point of the glass under a pressure lower than the internal pressure of the glass tube. As a result, the glass tube wall constituting the glass tube softens as the temperature of the glass tube rises, and the glass wall expands toward the inner surface of the mold due to the pressure difference between the inside and outside of the glass tube. It is formed into a shape.

  According to a fourth aspect of the present invention, there is provided a glass material forming method according to the second aspect, wherein the glass material is a tubular glass tube, and a mandrel whose outer surface is processed into a desired shape is disposed inside the glass tube. A step of heating and sealing both ends of the glass tube on which the mandrel is disposed, and a step of heating to a glass softening point under a pressure higher than the internal pressure of the sealed glass tube, It is characterized in that it is molded in advance into the shape of the outer surface of the mandrel.

  In the glass material molding method according to the fourth aspect of the invention, when the glass material is a tubular glass tube, a mandrel whose outer surface is processed into a desired shape is disposed inside the glass tube, and the mandrel is disposed. Both ends of the glass tube are heated and sealed, and heated to a softening point of the glass under a pressure higher than the internal pressure of the sealed glass tube. As a result, the glass tube wall constituting the glass tube softens as the temperature of the glass tube rises, and due to the pressure difference between the inside and outside of the glass tube, the tube wall shrinks in the direction of the outer surface of the mandrel, and the glass tube becomes the outer surface of the mandrel. It is formed into a shape.

  A glass material forming method according to a fifth invention is characterized in that, in the first invention, the glass material is spirally processed by rotating the glass material.

In the glass material molding method according to the fifth aspect of the invention, while rotating the glass material, the glass material is heated to a region where the viscosity is 10 ⁶ to 10 ⁸ poises, and the glass material is stretched in the region. A uniform spiral process is applied. In this region, continuous uniform molding is easy, and a spiral-processed glass material is molded with high accuracy and at low cost.

According to the method for molding a glass material of the present invention, the glass material is heated to a region exhibiting a viscosity of 10 ⁶ to 10 ⁸ poise, and the glass material is stretched in the region, whereby a small cross section excellent in uniformity. It is possible to manufacture a glass material having a high accuracy and at a low cost. In addition, since the glass material before redrawing has a large cross section, it is easy to form (process). Therefore, before redraw molding, the glass material is pre-processed into a shape similar to the desired shape, and the processed glass material is redrawn. A glass material having a desired shape can be produced by hot rolling by a forming method. Alternatively, if the glass material is hot-rolled by the redraw forming method while rotating, the glass material processed in a spiral manner can be produced, and thus excellent effects can be obtained.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.

(Embodiment 1)
FIG. 1 is an explanatory diagram for explaining a glass material forming method according to Embodiment 1 of the present invention. In the figure, reference numeral 10 denotes a glass material before redraw molding (hereinafter referred to as a base material), and the cross section (base material diameter φ1) of the base material 10 has a cross-sectional shape similar to the shape to be formed. Although details of the processing method of the base material 10 will be described later, since the base material diameter φ1 is large, processing is easy, and it is difficult to process after redraw molding, such as a rectangular shape, an elliptical shape, a semicircular shape, and the like. Pre-processed into shape.

  One end of the base material 10 is fixed to the base material folder 20, and the base material folder 20 is set to descend in the vertical direction at the descending speed V1. That is, the base material 10 is lowered at the lowering speed V <b> 1 by the base material folder 20. In addition, although the vertical installation type was shown in this embodiment, it cannot be overemphasized that a horizontal installation type may be sufficient.

  The base material 10 is heated by the heater 30 disposed in the path when the base material 10 is lowered. The heater 30 includes a plurality of burners 31, 31,..., And each burner 31 is provided with a temperature sensor (not shown). The temperature sensor detects the temperature at the position of the base material 10 heated by the burner 31. Further, a controller (not shown) is connected to the heater 30, and the controller outputs the output of each burner 31 so as to have a viscosity (FIG. 3) described later based on the temperature detected by the temperature sensor described above. Adjust as appropriate. More specifically, by controlling the amount of combustion gas and the proportion of oxygen mixed with the combustion gas, the size and temperature of the flame generated from the burner 31 can be adjusted. For example, the proportion of oxygen is increased. By using the burned gas, the temperature of the base material 10 at the position can be increased.

In this way, the base material 10 is heated so that the base material temperature exceeds the softening point, and is further pulled by the pulling roller 40 provided below, so that the glass material (hereinafter referred to as a fine material) whose cross section is smaller than that of the base material 10. 11). The pulling roller 40 is composed of a pair of rollers 40a and 40b having a radius R. Further, a control unit (not shown) is connected to the pulling roller 40, and the control unit uses the base material diameter φ1, the fine material diameter φ2, and the descending speed V1 to calculate the pulling speed V2 per se. (V2 = V1 × (φ1 / φ2) ² (Equation 1)) is calculated, and the operation of the pulling roller 40 is controlled. More specifically, the rollers 40a and 40b are appropriately adjusted by the control unit so that the rotation speed V3 is V3 = V2 / (2πR).

  By the way, there are innumerable fine cracks called Griffith Flow in the glass, and when the force concentrates on one of the cracks, the crack extends and the glass is broken, so that each of the rollers 40a and 40b. It is desirable to disperse the force exerted on the fine material 11 by the pulling roller 40 using a material whose contact surface with the fine material 11 matches the shape of the fine material 11.

  FIG. 2 is a top view of the pulling roller. When the cross-sectional shape of the fine material 11 is a circular shape (FIG. 2A), the rollers 40a and 40b are both concave shapes having a semicircular shape, and the cross-sectional shape of the fine material 11 is a semicircular shape. In FIG. 2 (b), if the roller 40a is formed in a concave shape having a semicircular shape and the roller 40a is formed in a convex shape having a semicircular shape, the force exerted on the fine material 11 by the pulling roller 40 can be dispersed. it can. Of course, when the cross-sectional shape of the thin material 11 is a quadrangle, an ellipse or the like, rollers 40a and 40b matching the outer shape may be used.

FIG. 3 is a graph showing an example of a change in viscosity of the glass material according to the present invention. In the figure, the horizontal axis indicates the position of the glass material when the entrance side of the heater 30 is defined as the origin and the traveling direction of the base material (downward in this example) is defined as the positive direction, and the vertical axis indicates the viscosity of the glass material at the position. Indicates. As shown in the graph of FIG. 4, the relationship between the temperature and the viscosity of the glass material is unique (the viscosity of the glass material decreases as the temperature increases). Viscosity was shown. For example, when the borosilicate glass (SiO ₂ —B ₂ O ₃ —Na ₂ O system) has a temperature range of about 800 to 950 ° C. and soda lime glass has a temperature range of about 700 to 850 ° C., the viscosity of the glass material is 10. ^It exhibits ⁶ to 10 ⁸ poise.

The illustrated graph is an example when the furnace length of the heater 30 is 300 mm, and the glass material according to the present invention is heated by the heater 30 in the region of 110 mm to 250 mm from the entrance side of the heater 30. The temperature range is 10 ⁶ to 10 ⁸ poise.

  In addition, if the glass material is heated or cooled rapidly, the glass material may be destroyed due to thermal shock, and therefore, a preheating region that heats gently in the region of 0 mm to 100 mm from the entrance side of the heater 30, and heating A slow cooling region for gently cooling in the region of 250 mm to 300 mm from the entrance side of the heater 30 is provided.

  Furthermore, it is important to create a steep temperature distribution so as to make the keep temperature region T of the highest temperature (corresponding to the lowest viscosity) that actually softens the glass as narrow as possible. In this example, the width of the keep temperature region T Is localized to 50 mm.

In a region where the viscosity of the glass material exhibits 10 ⁶ to 10 ⁸ poises by heating the glass material so as to achieve such a viscosity change and controlling the descent speed V1 and the pulling speed V2 so as to satisfy Equation 1. It was confirmed that it was possible to form a glass material having a completely similar shape to the base material 10 in which the fine material diameter φ2 was φ1 / 10 to φ1 (that is, the similarity ratio was 1/10 to 1). For example, in the case of a borosilicate glass tube (pyrex tube), the base material 10 is lowered at a lowering speed V1 of 35 to 45 mm / min, and the fine material 11 is pulled at a pulling speed V2 of 3500 to 4500 mm / min, approximately 800 to 950. When heated at a heating temperature of 0 ° C., the viscosity will be 10 ⁶ to 10 ⁸ poise, and can be molded into an arbitrary shape having a diameter of about 1/10 of the base material diameter φ1, and the temperature and tension By controlling the speed by the control unit, redraw molding can be performed with extremely high accuracy. In other words, when the viscosity of the glass material is lower than 10 ⁶ poise, irregular deformation of the glass material occurs, and the redraw molded fine material cannot maintain the surface state and shape and does not have a similar shape, When the viscosity of the glass material is higher than 10 ⁸ poise, the glass material is too hard and stretching becomes difficult.

  Next, a method for processing the base material 10 will be described. FIG. 5 is an explanatory diagram for explaining a method of processing a base material according to the present invention. Here, as an example, a case where the cross section of a Pyrex tube (glass standard tube) is processed from a circle to a quadrangle will be described.

  FIG. 5A shows a method of forming a base material having a square cross-sectional shape using a mold. First, both ends of the glass standard tube 50 are heated with a burner in the atmosphere to seal both ends and make the internal space completely airtight. Then, a glass standard tube 50 sealed at both ends is placed in a mold 51 made of carbon, SiC or the like whose inner surface is processed into a desired shape (quadrature in this example), and the glass is softened in a vacuum furnace. It heats to 650-750 degreeC which is (softening point). Since the inside of the glass standard tube 50 is filled with air and the outside of the tube is in a vacuum state, the pressure in the tube increases as the temperature rises, and the glass tube wall constituting the glass standard tube 50 softens. Due to the pressure difference between the inside and outside of the glass standard tube 50, the tube wall expands toward the inner surface of the mold 51 (arrow in the figure). The glass standard tube 50 is formed into the shape of the inner surface of the mold 51.

  FIG. 5B shows a method of forming a base material having a quadrangular cross-section using a mandrel. First, a mandrel 53 such as carbon, SiC or the like whose outer surface is processed into a desired shape (quadrature in this example) is placed in the tube of the glass standard tube 52, and both ends of the glass standard tube 52 are placed in a completely vacuum state in the inner space. Seal. And the glass standard tube 52 made into the vacuum state is heated to 650-750 degreeC which is the temperature (softening point) at which glass softens in an atmospheric furnace. Since the inside of the glass standard tube 52 is in a vacuum state and the atmosphere is filled outside the tube, the pressure outside the tube rises as the temperature rises, and the glass tube wall constituting the glass standard tube 52 Is softened, and the tube wall contracts in the direction of the outer surface of the mandrel 53 (arrow in the figure) due to the pressure difference between the inside and outside of the glass standard tube 52. Then, the glass standard tube 52 is formed into the shape of the outer surface of the mandrel 53.

  Thus, since the base material 10 is larger than the fine material 11, it is easy to process using the molding mold 51 or the mandrel 53. By using the mold 51 or the mandrel 53 having a desired shape, the fine material can be obtained. It can be processed into an arbitrary shape such as a rectangular shape, an elliptical shape, or a semicircular shape, which is difficult to process in a state. Therefore, if the base material 10 processed into an arbitrary shape in this way is stretched by the above-described redraw forming method, the fine material 11 having the target shape can be manufactured with high accuracy and at low cost.

(Embodiment 2)
FIG. 6 is an explanatory diagram for explaining a glass material forming method according to Embodiment 2 of the present invention. In the figure, reference numeral 60 denotes a bar-shaped base material. One end of the base material 60 is fixed to a base material folder 70, and the base material folder 70 is set to descend in the vertical direction at a descending speed V1. Further, the base material folder 70 is set to rotate at a predetermined rotational speed with the vertical direction as an axis.

The base material 60 is heated by the heater 30 disposed in the path when descending, the temperature of the base material 60 exceeds the softening point, and is further pulled by the pulling roller 40 provided below, so that the thin material is obtained. 61 is formed. When heating by the heater 30, as in the first embodiment, the output of each burner 31 is appropriately adjusted so that the viscosity becomes a temperature region exhibiting 10 ⁶ to 10 ⁸ poise. Since other configurations are the same as those in FIG. 1, the corresponding parts are denoted by the same reference numerals, and detailed description thereof is omitted.

As described above, the base material 60 is brought to a temperature range of 10 ⁶ to 10 ⁸ poises, and the base material folder 70 is rotated, whereby the thin material 61 can be subjected to uniform spiral processing. In particular, in this temperature range, continuous uniform molding is easy, and a spiral processed fine material can be manufactured with high accuracy and at low cost.

  In each embodiment, the base material holder 20 descends in the vertical direction at the lowering speed V1 and the base material 10 (60) is sequentially heated by the heater 30. However, the base material holder is fixed. Needless to say, the heater may rise in the vertical direction to sequentially heat the base material from the lower end.

Further, the glass material is not limited to the borosilicate glass and soda lime glass shown in the embodiment, and in general glass materials such as lead glass and quartz glass, the viscosity is 10 ⁶ to 10 ⁸ poise. By making the temperature range to be, a desired shape can be manufactured with high accuracy and at low cost.

  In recent years, microchips that form fine flow paths in a glass chip by micromachine technology, perform DNA analysis and blood analysis using the flow of reagents in the flow paths, and perform reactions and synthesis of various substances have been developed. It has been actively researched, and there is a strong demand for the realization of a constant-rate injection mechanism for the chip. According to the forming method according to the present invention, since the surface of the fine material 61 (glass rod) having an arbitrary diameter can be subjected to uniform spiral processing, as shown in FIG. By fitting the tube 81 with high accuracy, the cross section of the spiral hole 82 generated from the thin material 61 and the tube 81 can be made uniform, and the injection pump 80 capable of flowing the reagent at a uniform speed is manufactured. be able to.

It is explanatory drawing for demonstrating the shaping | molding method of the glass material which concerns on Embodiment 1 of this invention. It is a top view of a pulling roller. It is a graph which shows an example of the viscosity change of the glass material which concerns on this invention. It is a graph which shows the viscosity characteristic of a glass material. It is explanatory drawing for demonstrating the processing method of the base material which concerns on this invention. It is explanatory drawing for demonstrating the shaping | molding method of the glass material which concerns on Embodiment 2 of this invention. It is sectional drawing of the liquid injection pump using the fine material (glass rod) shape | molded by the shaping | molding method of the glass material which concerns on Embodiment 2 of this invention.

Explanation of symbols

10, 60 Base material 11, 61 Fine material 20, 70 Base material folder 30 Heater 31 Burner 40 Pulling roller 40a, 40b Roller 51 Mold 53 Mandrel

Claims (5)

In hot-rolling a glass material by a redraw molding method, the glass material is heated to a predetermined viscosity, and the glass material is molded by controlling the pulling speed of the glass material.
The method for molding a glass material, wherein the predetermined viscosity is 10 ⁶ to 10 ⁸ poise. Pre-form a glass material into a cross-sectional shape similar to the desired shape,
The method for molding a glass material according to claim 1, wherein the molded glass material is formed into a desired shape by a redraw molding method. The glass material is a tubular glass tube,
Heating both ends of the glass tube and enclosing a gas inside;
Placing the glass tube enclosing the gas in a mold whose inner surface is processed into a desired shape; and
Heating to the softening point of the glass under a pressure lower than the internal pressure of the glass tube,
3. The method for molding a glass material according to claim 2, wherein the glass tube is previously molded into the shape of the inner surface of the mold. The glass material is a tubular glass tube,
Placing a mandrel whose outer surface is processed into a desired shape inside the glass tube;
Heating and sealing both ends of the glass tube on which the mandrel is disposed;
A step of heating to a softening point of the glass under a pressure higher than the internal pressure of the sealed glass tube,
The method for molding a glass material according to claim 2, wherein the glass tube is previously molded into a shape of an outer surface of a mandrel.   The glass material forming method according to claim 1, wherein the glass material is spirally processed by rotating the glass material.

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