JP2007091494A - Glass forming dies and glass forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide glass forming dies capable of manufacturing glass rods having various sizes and shapes in a short time by partially replacing components of the dies. <P>SOLUTION: The glass forming dies 30 are composed of a flowing inlet 31, a cartridge 37 having a drawing outlet and a penetrating through-hole, and a body of dies 35 set around the cartridge 37. The cartridge 37 is cylindrically installed in the glass forming dies 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a glass forming die and a rod-shaped glass forming apparatus for forming molten glass into a rod-shaped glass, for example, in an optical element manufacturing process.

  In recent years, substrates made of glass or glass ceramics have been actively used as substrates for information recording media used in hard disk drives. As such a glass substrate for a hard disk drive, a disk-shaped glass having a hole in the center is used. This disk-shaped glass is manufactured by slicing a glass formed into a round bar shape to a predetermined thickness, forming a hole in the center of the sliced glass, and further performing grinding and polishing.

  Conventionally, the following round bar glass forming apparatus is known as an apparatus for molding such round bar glass. The round bar glass forming apparatus includes, for example, an outflow pipe having an outflow port through which molten glass flows out, and a forming die having a through hole penetrating substantially linearly from the inflow port to the extraction port. In addition, an inlet of the forming die is disposed below the outlet of the outlet pipe.

  According to this round bar glass forming apparatus, first, molten glass flows from the outlet of the outflow pipe to the inlet of the forming die. The molten glass that has flowed in flows into the drawing port by its own weight while dissipating heat in contact with the inner wall forming the through hole of the forming die. The molten glass whose temperature has decreased due to heat dissipation increases in viscosity and is lowered from the outlet while being formed into a round bar glass having a cross-sectional dimension corresponding to the inner diameter of the through hole. As described above, the conventional round bar glass forming apparatus operates to form round bar glass.

For such a conventional round bar glass forming apparatus, for example, in Patent Document 1, the molten glass is allowed to flow down in contact with a cylindrical surface of a refractory material that does not wet the heated glass. The manufacturing apparatus which manufactures rod-shaped glass continuously by making it cool and solidify is disclosed. As the shape of the cylindrical mold used for the cylindrical surface of the refractory material, a circular shape and an isosceles triangular shape are disclosed. Any cross-sectional shape can be selected for these shapes, and since there is no restriction on the cross-sectional shape of the rod-shaped glass due to the presence of a free surface, round rods for lenses, triangular rods for prisms, and pentaprisms Can be continuously manufactured easily.
Japanese Patent Publication No.49-10806

  However, in the rod-shaped glass forming apparatus disclosed in Patent Document 1, in order to manufacture a bar-shaped glass having a different shape, a forming die including a cylindrical mold has to be replaced after the manufacturing. Therefore, every time the forming die is replaced, the inner hole and the outflow pipe of the cylindrical mold must be set on the same center line, which may cause a reduction in production efficiency.

  The present invention has been made in view of the problems as described above, and when changing the molding size and shape of the rod-shaped glass, it is possible to produce a variety of shapes of rod-shaped glass in a short time by exchanging only by partial replacement. A glass forming die and a glass forming apparatus can be provided.

  As a result of intensive research to solve the above problems, the present inventors have found that the above problems can be solved by arranging a replaceable cartridge part in a glass forming die and exchanging the cartridge part. The present invention has been completed. More specifically, the present invention provides the following.

  (1) A glass molding die comprising an inflow port, a draw-out port and a cartridge part having a through-hole penetrating them, and a die body part loaded around the cartridge part, wherein the cartridge part is A glass forming die arranged in a cylindrical shape in a glass forming die.

  According to the glass forming die of the present invention, since the cartridge part having the through hole arranged in the glass forming die can be replaced, the size and / or shape of the through hole can be changed by replacing only the cartridge part. Bar glass with different sizes and / or shapes can be produced. In addition, since the glass forming die is fixed, the center of the through hole and the center of the outflow port do not deviate when replacing the cartridge part. Therefore, it is not necessary to align the center of the through hole and the outlet again (centering), so that productivity can be improved. In particular, in the production of a small lot, when frequent replacement must be performed, the production can be performed without reducing productivity.

  (2) It has a heating means provided in the vicinity of the inflow port and a cooling means provided in the vicinity of the outlet if necessary, and the heating means and the cooling means are provided on the die body portion. The glass forming die according to (1), which is provided.

  According to this aspect, since the heating means and the cooling means are provided in the die body portion, the cartridge portion can be configured with only the through hole, and the configuration of the cartridge portion can be simplified. The replacement can be easily performed.

  (3) The glass forming die according to (1) or (2), wherein the cartridge portion is replaceable with a different type in cross-sectional shape and / or cross-sectional diameter of the through hole.

  According to this aspect, the rod-shaped glass corresponding to the cross-sectional shape and / or cross-sectional diameter of the through hole can be easily formed by exchanging the cartridge part.

  (4) In the cartridge portion, the cross-sectional shape of the through hole is a circle or a substantially circular shape, and the diameter of the through hole when converted into a circle is in a range from 0.5 inch to 4.0 inch. The glass forming die according to (3), wherein the die can be replaced with a plurality of types of cartridge parts.

  According to this aspect, since a rod-like glass having a diameter in the range of 0.5 inch to 4.0 inch can be formed in a circular or substantially circular shape, the glass for lenses, information recording disks, and glass substrates can be formed. It can be suitably used as a molding die. The ratio between the radius and the length of the cross section of the through hole is preferably in the range of 1: 1 to 1: 100, more preferably 1: 2 to 1:90, and most preferably 1: 3 to 1:80. It becomes.

  (5) The glass forming die according to (3), wherein a cross-sectional shape of the through hole of the cartridge portion is a polygonal shape.

  According to this aspect, a polygonal rod-shaped glass corresponding to the cross-sectional shape of the through hole can be formed. Since glass has viscosity, it has the property of rounding, but the through hole has a polygonal shape and is pulled out at a predetermined drawing speed with a driving roller provided below the drawing port of the glass forming die. Thus, a rod-shaped glass having a through-hole shape can be easily manufactured. Among polygons, triangles can be used as prisms, and pentagons can be used as pentaprisms.

  (6) The glass forming die according to any one of (1) to (5), and an outflow pipe having an outflow port for flowing out the molten glass, wherein the inflow port is provided below the outflow port of the outflow pipe. Arranged rod-shaped glass forming device.

  According to this aspect, the molten glass is caused to flow from the outlet of the outlet pipe to the inlet of the glass forming die. The molten glass that has flowed in is brought into contact with the inner wall of the through-hole of the glass forming die and radiates heat while flowing into the drawing port by its own weight. At that time, the molten glass descends from the outlet while being formed into a rod-shaped glass having a cross-section corresponding to the cross-sectional shape of the through hole. Here, since the said rod-shaped glass shaping | molding apparatus is equipped with the glass shaping | molding die described in (1) to (5), there can exist an effect similar to the effect described by the glass shaping | molding die mentioned above. .

  (7) The rod-shaped glass forming apparatus according to (6), wherein the outflow pipe is provided at a substantially central portion of a cross section of the glass forming die, and includes a nozzle capable of ejecting gas from a tip portion of the outflow pipe.

  According to this aspect, a predetermined amount of gas per unit time is continuously ejected from the nozzle provided in the outflow pipe to the substantially central portion of the molten glass. As described above, since the gas is ejected from the nozzle and the hole is formed while the molten glass is allowed to flow through the through-hole, the hollow rod-shaped glass with little breakage and striae can be stably formed.

  According to the glass forming die and the rod-shaped glass forming apparatus of the present invention, the molten glass is caused to flow from the outlet of the outflow pipe to the inlet of the glass forming die. The molten glass that has flowed in flows into the drawing port by its own weight while dissipating heat while contacting the inner wall of the through hole of the cartridge portion provided in the glass forming die. At that time, the molten glass is lowered from the outlet while being formed into a rod-like glass having a cross section corresponding to the cross-sectional shape of the through hole. Here, since the cartridge part is replaceable, the size and / or shape of the through hole can be changed by replacing only the cartridge part. Therefore, rod-shaped glasses having different sizes and / or shapes can be produced, and various types of molding can be performed in a short time.

<Overall configuration>
FIG. 1 is a sectional view of a rod-shaped glass forming apparatus 1 of the present invention. The rod-shaped glass forming apparatus 1 has a melting furnace 10, a flow rate control pipe 20 as an outflow pipe, a glass forming die 30, and a plurality of drive rollers 40 as a drawing speed control means.

  The melting furnace 10 is provided at a position higher than the glass forming die 30, and a flow rate control pipe 20 extending downward is connected to the bottom of the melting furnace 10. Further, the melting furnace 10 is maintained at a high temperature, and molten glass that is uniformly melted is accommodated in the furnace. When the molten glass flows out from the melting furnace, the height of the melting furnace can be set at an arbitrary position in the case of using a method in which the molten glass is discharged under pressure.

  One end of the flow rate control pipe 20 is connected to the melting furnace 10, and the other end is arranged as an outlet 21 vertically downward. Below the outlet 21, an inlet 31 of a glass forming die 30 described later is installed. In addition, the flow rate control pipe 20 includes platinum and / or gold as its material, and is configured such that a current flows through the pipe itself.

  The driving roller 40 includes a roller and a driving unit that rotationally drives the roller. Each drive roller 40 is provided below a drawer port 32 of a glass forming die 30 to be described later, and each part on an axis extending vertically downward from the center of the drawer port 32 is sandwiched between two drive rollers 40. Is provided. Further, as the material of each roller, a material that has poor thermal conductivity and does not slide due to engagement with glass formed in a round bar of 200 to 600 ° C. is used. In the rod-shaped glass forming apparatus 1 of the present invention, for example, a material made of ductile cast iron and carbon is used.

<Die for glass molding>
FIG. 2 is an enlarged cross-sectional view of the glass forming die 30 and the outlet 21 of the flow rate control pipe 20, and FIG. 3 is an exploded perspective view of the glass forming die 30.

  The glass forming die 30 includes a cartridge portion 37 that includes a through hole 36 and is disposed in a cylindrical shape at a substantially central portion of the glass forming die, and a die that is disposed in close contact with the cartridge portion 37 around the cartridge portion 37. A cylindrical die composed of a main body portion 35. The cartridge portion 37 is formed with a through hole 36 having a substantially circular cross-sectional shape along the central axis. Both ends of the through hole 36 are an inlet 31 and a drawer 32. That is, the glass forming die 30 is formed with a through-hole 36 that extends substantially linearly from the inlet 31 to the outlet 32. Here, the inner diameter of the inflow port 31 is formed larger than the inner diameter of the outflow port 21 of the flow rate control pipe 20. Further, the inner diameter of the through hole 36 is narrowed from the inflow port 31 to a predetermined inner diameter, and is expanded toward the extraction port 32. The glass forming die 30 is arranged so that the central axis of the through hole 36 is in the vertical direction, and the inlet 31 is located below the outlet 21 of the flow rate control pipe 20.

  In the glass molding die of the present invention, it is preferable that the through-hole provided in the cartridge portion penetrates the inlet and the outlet substantially linearly. It does not exclude that the diameter changes discontinuously or is bent.

  Further, it is preferable that the cartridge portion is mounted in close contact with the substantially central portion of the die body in order to improve heat conduction from the die body. However, the cartridge portion and the die main body portion do not necessarily need to be in close contact with each other, and a partial space may be formed between them depending on circumstances. Further, the loading position of the cartridge part is preferably substantially the center part of the die body part, but other aspects are not excluded.

  In the rod-shaped glass forming apparatus 1 of the present invention, ductile cast iron is used as the material of the glass forming die 30. However, as long as the heat conductivity is high and the material is heat resistant, other than ductile cast iron, for example, a carbon-based material may be used. Good.

  When the cartridge part 37 is brought into close contact with the die body part 35, the inner diameter of the mounting part 39 of the cartridge part 37 of the die body part 35 is preferably slightly larger than the outer diameter of the cartridge part 37. Thereby, the cartridge part 37 can be thermally expanded by the heating at the time of shaping | molding, and can be closely_contact | adhered with the die body part 35. FIG. Further, even after molding, the cartridge portion 37 contracts due to cooling, so that it can be easily detached from the die body portion 35.

  The thickness of the cartridge part 37, that is, the dimension from the wall surface of the through hole 36 to the wall surface of the outer diameter of the cartridge part 37 is not particularly limited, and the wall surface of the through hole 36 of the cartridge part 37 expands due to heat during manufacture, It may be in a range where the glass to be manufactured does not deform. Although the coefficient of thermal expansion depends on the material of the cartridge part 37 and the glass composition to be manufactured, when the through hole is circular or substantially circular, the thickness is preferably 10 mm or more.

  The inner diameter of the through-hole 36 is preferably used as an information recording disk and a glass substrate, so that it can be exchanged for a plurality of types of cartridge parts within a range of 0.5 inch to 4.0 inch. Within this range, 0.85 inch, 1.0 inch, 1.8 inch, 2.5 inch, 3.0 inch or 3.5 inch is preferable and preferably 1 inch. Most preferred.

  The cross-sectional shape of the through-hole 36 is not particularly limited and can be changed according to the glass to be manufactured, but is preferably a substantially circular or polygonal cross-sectional shape. Examples of the cross-sectional shape on the polygon include a triangle, a quadrangle, and a pentagon. In addition, when it is desired to form a rod-shaped glass having a cross-sectional shape other than a substantially circular shape or a polygonal shape, it may be replaced with a cartridge portion having a desired cross-sectional shape. For example, the cross-sectional shape may be a shape in which the distance from the center of the cross-section to the outer edge is not constant. As another example of the cartridge portion, FIG. 4 shows a cartridge portion 37 ′ in which the through hole has a triangular cross-sectional shape. The triangular bar graph can be used as glass for a prism. Circular glass can be used for lenses.

  The die body 35 can be provided with a cartridge heater 33 as a heating means and a cooling device 34. As shown in FIG. 3, a plurality of holes extending so as to be parallel to the through holes 36 are provided on the end surface on the inlet 31 side of the glass forming die 30. The plurality of holes are provided with a predetermined dimension away from the inner wall surface forming the through hole 36, and the rod-shaped cartridge heater 33 can be inserted therein.

  On the other hand, an annular recess is formed on the drawing port 32 side of the glass forming die 30, thereby forming a protruding wall 38. An annular cooling device 34 as a cooling means is detachably provided in the recess. The cooling device 34 uses a liquid as a refrigerant, and a water passage extending in an annular shape is formed therein, and a refrigerant inlet (not shown) for injecting the refrigerant into the water passage is formed on the outer surface thereof. A refrigerant discharge port (not shown) through which the refrigerant passing through the water passage is discharged is provided. In addition, in the rod-shaped glass forming apparatus 1 of the present invention, water is used as the coolant, but the present invention is not limited to this, and a gas such as air can also be used. The above cooling device 34 can cool the inner wall surface of the wall portion 38 of the glass forming die 30 by injecting cooling water into the water passage.

<Action>
The rod-shaped glass forming apparatus 1 of the present embodiment operates as follows, for example. First, molten glass melted in the furnace of the melting furnace 10 flows down from the melting furnace 10 to the flow rate control pipe 20 at a predetermined flow rate. The molten glass that has flowed down flows through the flow rate control pipe 20 and flows out from the outlet 21 to the inlet 31 of the glass forming die 30 disposed below. Further, when molten glass flows through the flow control pipe 20, a predetermined amount of current flows through the flow control pipe 20, and the flow control pipe 20 itself can generate heat according to the amount of current. Then, the temperature of the molten glass flowing through the flow rate control pipe 20 changes, the viscosity of the molten glass changes accordingly, and the speed at which the molten glass flows also changes. In this manner, the amount of molten glass flowing out per unit time from the outlet 21 of the flow rate control pipe 20 is controlled.

  Next, the molten glass flowing into the inlet 31 of the glass forming die 30 is heated by a plurality of cartridge heaters 33 provided close to the inlet 31. The heated molten glass flows downward from the inlet 31 through the through hole 36 due to its own weight. At this time, the molten glass dissipates heat in contact with the inner wall forming the through hole 36. The molten glass whose temperature has decreased due to heat dissipation increases in viscosity and reaches the outlet 32 while being formed into a rod-like glass having a cross section corresponding to the cross-sectional shape of the through hole 36. In the vicinity of the drawing port 32, the molten glass is further cooled by a cooling device 34 provided close to the drawing port 32, and is lowered from the drawing port 32 as shaped glass.

  Next, the molded glass lowered from the drawing port 32 of the glass forming die 30 is sandwiched by a driving roller 40 that rotates downward, and is drawn downward at a drawing speed corresponding to the rotational speed of the driving roller 40. .

  When molding glass rods of different sizes and / or shapes after molding, the glass rods of different sizes and / or shapes can be molded by exchanging only the cartridge portion 37. By exchanging only the cartridge portion 37, it is not necessary to align the center of the inlet and the through hole every molding, so that productivity can be improved. In particular, if the center of the inlet and the through hole is off, the temperature distribution of the molten glass passing through the through hole will not be uniform, causing wrinkles on the surface of the formed rod-shaped glass or devitrification of the glass. It becomes.

  Further, it is preferable that the outer diameter of the cartridge portion 37 is constant. Since the thickness of the cartridge portion 37 differs depending on the size of the inner diameter of the through hole 36, when the inner diameter of the through hole 36 is increased, the thickness of the cartridge portion 37 is reduced, so that a sufficient cooling effect can be obtained. Conversely, when the inner diameter of the through-hole 36 is reduced, the thickness of the cartridge portion 37 is increased, but the amount of molten glass passing therethrough is reduced, so that there is almost no difference in the cooling effect. Further, the cartridge heater 33 and the cooling device 34 are provided in the die body 35. Therefore, the cartridge portion 37 can be configured only by the through hole 36, the configuration of the cartridge portion 37 can be simplified, and replacement can be easily performed.

  It should be noted that the present invention is not limited to the above-described apparatus, and modifications and improvements as long as the object of the present invention can be achieved are included in the present invention. For example, as shown in JP-A-2005-89275, the central axis of the through hole of the glass forming die may be inclined.

Sectional drawing of the rod-shaped glass shaping | molding apparatus of this invention. The expanded sectional view of the glass forming die of the said rod-shaped glass forming apparatus, and the outflow port of a flow control pipe. The disassembled perspective view of the glass shaping | molding die of the said rod-shaped glass shaping | molding apparatus. The perspective view of the cartridge part which shows the other shape of a through-hole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bar-shaped glass forming apparatus 20 Flow control pipe 21 Outlet 30 Glass forming die 31, 31 'Inlet 32 Drawer port 33 Cartridge heater 34 Cooling device 35 Die body part 36 Through-hole 37, 37' Cartridge part 38 Wall part 39 Installation Part 40 Drive roller

Claims (7)

A glass molding die comprising an inflow port, a drawer port and a cartridge part having a through-hole penetrating them, and a die main body part loaded around the cartridge part,
The cartridge part is a glass forming die arranged in a cylindrical shape in the glass forming die. A heating means provided in the vicinity of the inlet, and a cooling means provided in the vicinity of the outlet if necessary,
The glass forming die according to claim 1, wherein the heating means and the cooling means are provided in the die body.   The glass forming die according to claim 1 or 2, wherein the cartridge part is replaceable with a different type of cross-sectional shape and / or cross-sectional diameter of the through hole.   In the cartridge portion, the cross-sectional shape of the through hole is a circle or a substantially circular shape, and the diameter of the through hole when converted into a circle is in a range from 0.5 inch to 4.0 inch, The glass forming die according to claim 3, wherein the die can be exchanged for a plurality of types of cartridge parts.   The glass forming die according to claim 3, wherein a cross-sectional shape of the through hole of the cartridge portion is a polygonal shape. A glass forming die according to any one of claims 1 to 5,
An outflow pipe having an outlet for flowing out the molten glass,
A rod-shaped glass forming apparatus in which the inlet is arranged below the outlet of the outlet pipe.   The rod-shaped glass forming apparatus according to claim 6, wherein the outflow pipe includes a nozzle that is arranged at a substantially central portion of a cross section of the glass forming die and is capable of ejecting a gas from a front end portion of the outflow pipe.

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