JP3103272B2 - Equipment for manufacturing quartz glass articles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of a quartz glass article having a projection formed on at least one surface of a quartz glass body. A flange portion of a furnace core tube, a top plate or a bottom plate of a vertical wafer carrier, a side plate of a horizontal wafer carrier, a quartz glass jig such as a furnace core tube cap and a component thereof, etc. The present invention relates to an invention for efficiently manufacturing a quartz glass article having a flange portion and the like.

[0002]

2. Description of the Related Art Conventionally, when a quartz glass member having such a complicated shape is manufactured, a welding rod of quartz glass is heated and melted by a burner heating on a quartz glass flat plate, and successively cladding is performed. Has been manufactured by grinding and shaping into a predetermined shape, or by shaving from a quartz block body. However, the work time is extremely long in the case of overlaying with a welding rod, and if the welding speed and the heating temperature are not properly adjusted, bubbles may be chewed. The work time was bad because of the fire processing. In addition, there is a problem that the material unit consumption is large in the machining of the block material and that a long time is required for the grinding.

In order to solve such a drawback, a heat molding method for heating and softening the quartz glass body in a molding die to form the projections has been studied. In this type of molding, for example, as shown in JP-A-1-317132, after a quartz glass base material is heated to a high temperature of 1600 to 1800 ° C. in a molding container, a molding pressure is applied from both directions symmetrical to the base material. In addition, it is configured to perform pressure molding. In such a molding method, for example, the molding pressure is set to 100 kgf / cm.
^{When the} molding is performed at such a high pressure, graphite and quartz glass constituting the molding frame adhere to each other at high pressure under high temperature, so that CO and CO ₂ are further reacted by the reaction of graphite and quartz glass. In this case, vapors of SiO ₂ were generated, and these gases entered the softened quartz glass, and not only bubbles were generated, but also SiC generated by the reaction adhered to the quartz glass surface and was cooled to room temperature. At this time, cracks occur due to the difference in the coefficient of thermal expansion between the two.

For this reason, for example, Japanese Patent Publication No. 62-50414
It is devised to CO ₂ to escape from the fiber layer by lining the graphite fiber cloth to the inner surface of the forming frame in No..
This technique, according to the actual embodiment disclosed in the specification, is held at 1850 ± 5 ° C. for 30 minutes and the inert gas N ²
Pressure molding was successfully performed at 0.4 km / cm ² in an atmosphere. This is because the lining graphite fiber cloth is made of SiO ²
And so on, thereby improving the yield by preventing vapor gas from being released into the product as air bubbles.

[0005]

However, in the structure in which the fiber layer is lined, if the original ingot melts and comes into close contact with the cushioning material on the side wall, the exhaust gas passage is limited to the pores of the cushioning material on the side wall, and the exhaust gas passage is limited to the bottom side. In the mechanism having a projection on the bottom as in the article according to the present invention, not only the retention of gas at the bottom leads to a very serious defect, but also a female recess corresponding to the projection. It is virtually impossible to lay the cushioning material uniformly.

In order to prevent such a drawback, an apparatus in which the heating temperature is set to a low temperature of 1600 ° C. to 1700 ° C., a molding hole having a through hole having a diameter of about 3 mm, and molding without pressurization is disclosed in Japanese Patent Application Laid-Open No. HEI 9-163873. No. 5-17174.

However, in such a mechanism, the heating temperature is 1
Since the viscosity is as low as 600 ° C. to 1700 ° C. and the pressure is not applied, in the case of the article according to the present invention, the molten glass cannot be sufficiently wrapped around the flat protruding portion, so that accurate processing is also impossible. Will be possible.

The present invention has been made in view of the above-mentioned conventional drawbacks, and even in the case of processing a quartz glass article having a projection, it is possible to form a quartz glass article with no bubbles, no devitrification or cracks on the surface, and which can be formed with high precision. It is an object of the present invention to provide an invention for manufacturing a glass article.

[0009]

SUMMARY OF THE INVENTION The present invention provides a graph
Quartz glass body housed in molding space with aite frame
The female type corresponding to the protrusion on the lower surface side with the
A mold for molding comprising a cradle for the glass body is first formed.
Placed in the furnace space where the heating element is surrounded, and
And press forming the quartz glass body under high temperature heating
Applied to equipment for manufacturing quartz glass articles with projections
Shall in, and has as its first aspect, the cradle and the female graphite material, specifically a porous graphite material, whereas for molding to respectively form the graphite frame with dense graphite material While configuring as a formwork,
A support for fixedly supporting the pedestal on the upper surface side, a work table disposed on a lower position facing the support, on which the molding form is placed, and a work table for lowering the work table from a lower position outside the furnace. And a fluid pressure urging means connected to the lower side of the worktable. The invention according to claim 1, wherein the deforming completion position is accurately maintained by the liquid pressure urging means. It is characterized in that the moving speed is set to 2 to 10 mm / min while moving the female die in a pressing direction by a hydraulic cylinder constituting a fluid pressure urging means. In this case, preferably, after the upper surface of the pedestal is fixed to the support by raising the elevating means, the quartz glass body is pressed under a high temperature while applying a small pressing force to the quartz glass body via the female mold by the fluid pressure urging means. It is preferable to perform pressure molding.

In this case, the fluid pressure urging means is constituted by a hydraulic cylinder via a pressure detecting means, and the pressure detecting means reduces the minute pressing force applied to the softened quartz glass body via the female mold by 0.01. It is preferable to be configured to be controllable in the range of 0.5 kgf / cm ² to 0.5 kgf / cm ² . Further, the glass body housed in the mold is preferably configured to be capable of generating heat by induction heating means in order to enable quick temperature rise.

The invention according to claim 2 further comprises a detecting means for detecting the amount of movement of the fluid pressure urging means in order to make the molding process more accurate, and the furnace temperature is set at 17 ° C.
After reaching the temperature range of about 00 to 2000 ° C. and detecting the deformation completion position of the quartz glass body by the detection means, holding the molding completion position for a predetermined time, and then applying the female mold through the fluid pressure urging means. Is lowered in the return direction. Further, in order to facilitate continuous molding, the invention according to claim 6 is configured such that an opening is provided below a furnace space in which the heating element is surrounded, and the worktable can enter the furnace into the opening.
It is configured to be openable and closable via two shutters made of graphite material . Specifically, of the two shutters, the upper shutter facing the furnace space is located on the lower side by a single-layer graphite material. The lower shutter is formed of a laminated graphite material.

[0012]

[0013]

As described above, in order to perform accurate heating,
It is necessary to perform high-temperature heating of about 1700 to 2000 ° C. However, when high-temperature heating is performed, CO and C are generated by the reaction between graphite and quartz glass as described above.
Evaporation gas of O ₂ and further SiO ₂ is generated, generating bubbles of quartz glass, cracks and devitrification. Such measures are taken from both the molding frame and the molding pressure device.

First, the molding frame will be described. In a method of molding a quartz glass article by sandwiching a quartz glass body between a female mold having a graphite frame surrounding the periphery and a pedestal, FIG.
As shown in FIG. 4 to FIG. 4, a female mold and a pedestal are always in contact with the quartz glass body at the time of pressure molding (these are called push molds).
Therefore, the reaction with quartz glass causes CO and C
O ₂ and SiC vapor are generated only on the contact surface of the pressing die. Also, even if the SiO ₂ evaporating gas is generated around the glass body due to the heating of the glass body, the quartz glass body is not in contact with the surrounding graphite frame until immediately before the molding is completed. You don't have to worry about escape. Therefore, it is sufficient to provide a gas escape path only in the pair of pressing dies, but it is impossible to deform the graphite fiber cloth of the former technology in accordance with the shape of the female protrusion.

On the other hand, in a case where pores of about 3 mm are pierced as in the latter conventional technique, quartz glass having a high viscosity is used.
No problem occurs at 600 to 1700 ° C, but 1900 ° C
When the temperature is raised to such a level, the viscosity of the quartz glass is greatly reduced, and irregularities are formed on the surface of the molded quartz glass article.
Therefore, in the present invention, a stamping die is formed by using porous graphite in which the graphite material itself has air permeability, such as sintered graphite. That is, press this case preferably the gas permeability 0.1 cm ² value of /sec(P:1.5Kgf/cm ²⁾ or more, more preferably equipped with micro gas permeation hole group of 0.9 cm ² / sec longitudinal The mold is used.

A graphite material having a bulk density of 1.5 g / cm ³ or less may be used as the porous graphite material. However, if the bulk density is too low, breakage or deformation occurs during pressure molding. Therefore, it is preferably 1.2 ± 0.
It is good to set to 2 g / cm ³ . In order to mold with high precision without causing breakage or deformation during pressure molding, the compression strength is 100 kgf / cm ² or more, preferably 150 to 6 kgf / cm ^2.
It is necessary to set 00 Kgf / cm ² and the Shore hardness to 10 or more, preferably around 15 ± 2.

On the other hand, since the pressing die is always in contact with the quartz glass body at the time of pressure molding, when impurities are present on the graphite side due to the contact, the semiconductor poison is proportionally applied to the surface of the quartz glass body. And a cristobalite layer are formed, which again causes devitrification and cracks. Therefore, each of the metal elements that cause semiconductor poisons such as Na, K, Li, Ca, Mg, and Fe and the cristobalite layer is 0.1 to 0.1%.
It is preferable to set the concentration to 0.2 ppm or less.

On the other hand, in the vicinity of the completion of the molding of the quartz glass body, since the expansion force from the softened outer peripheral surface of the quartz glass body is urged against the inner wall surface of the graphite frame, the graphite frame is formed of a dense graphite material. It is necessary to make the bending strength several steps larger than the above-mentioned press die. Flexural strength towards the pressing mold in this case is 30kg / cm ² or more, preferably in the order may be set respectively for 50~300kg / cm ^2, bending strength of the graphite frame, more,
Specifically, it may be set to about 350 to 900 kg / cm ² . Therefore, the molding frame of the present invention is characterized in that the composition of the two types of graphite molds of the female mold, the cradle, and the graphite frame is different.

Next, examination will be made from the aspect of molding. This processing, as mentioned above, heating temperature around 1700-2000 ℃,
Preferably by setting to 1840 ~ 1980 ℃,
The viscosity is reduced and molding can be facilitated. In this case, in the case of natural quartz glass produced by an oxyhydrogen flame, the heating temperature is 18
The heating temperature is set to about 40 to 1900 ° C., and in the case of natural quartz glass produced by the electrofusion method, to the heating temperature of about 1900 to 1960 ° C. In this case, the molding may be performed without pressure. However, if the molding is performed without pressure, the pressing force changes due to the weight of the pressing die, which is not preferable. On the other hand, if the pressing force is set to a large value, even if the molding frame is used, the contact between the molding frame and the fused silica glass becomes too strong, and the generation of the reactive gas cannot be suppressed. Therefore, the present invention is set so as to minimize the contact time and contact area between the molding frame and the fused silica glass in the high-temperature heating region. It is also necessary to devise an apparatus that can facilitate continuous molding.

Therefore, the present invention provides a support for fixedly supporting the receiving table on the upper surface side, a work table which is disposed at a lower position facing the support and on which the molding form is placed, and The present invention proposes a molding apparatus including elevating means for elevating and lowering a table from a lower position outside the furnace into the furnace, and fluid pressure urging means continuously provided below the work table.

That is, according to the present invention, the upper surface of the pedestal is fixed to the support by the raising and lowering means, and then a small pressure is applied to the quartz glass body via the female mold by the fluid pressure urging means, specifically, By performing pressure molding under high-temperature heating while applying a small pressing force in the range of 0.01 to 0.5 kgf / cm ² , preferably 0.02 to 0.2 kgf / cm ² ,
The reaction can be suppressed by reducing the contact area between the quartz glass body and the graphite as much as possible while maintaining accurate molding at a constant molding pressure. In this case, it is preferable to use an incompressible hydraulic cylinder as the fluid pressure urging means. In particular, by configuring the hydraulic cylinder via a pressure detecting means, the pressurizing force can be accurately maintained. Further, the minute pressing force applied to the quartz glass body via the female mold by the fluid pressure urging means is pre-pressed to the female mold from a temperature range before the quartz glass body starts to be deformed, so that the degree of heat softening is increased. Since the molding process is performed gradually according to the above, the molding process can be performed with high accuracy, which is preferable.

Further, the present invention employs a structure in which pressure is applied from a work table disposed on the lower side through a female mold, and the female mold is configured to directly bite into the softened quartz glass body. Thus, accurate projection molding can be performed. Further, since the receiving table on the upper side of the molding frame has a fixed pressure, it is sufficient to open only the lower side in the furnace where the work table is raised and lowered without opening the upper side in the furnace. As a result, in the conventional configuration in which the inside of the furnace is opened, each time the furnace is opened, the furnace temperature drops to near room temperature, and the temperature rise time in the next molding process becomes extremely long. Since the atmosphere can be left in the furnace, it is very advantageous as an apparatus for performing continuous molding.

In this case, in order to facilitate continuous molding, an opening is provided below the furnace space in which the heating element is surrounded, and two shutters are provided in the opening. The upper shutter facing the space is made of a single-layer graphite material with good heat insulation, and the lower shutter located on the lower side is made of a laminated graphite material that is alternately laminated with, for example, a quartz glass plate, so that the heat resistance and heat insulation in the former are achieved. The sealability and strength can be maintained with the latter. The glass body is heated by the induction heating means so that the temperature can be quickly raised to the heating area, and the molding time, in other words, the contact time between the molding frame and the fused silica glass is minimized. On the other hand, if the heating rate is too fast, the temperature difference between the peripheral area and the central area of the glass body becomes large, and accurate molding cannot be performed. Therefore, in the present invention, the heating rate of the glass body after heat softening is set to 35 to 55 ° C./mi.
n, preferably 40 to 50 ° C./min.

It is to be noted that the moving speed of the elevating means is set so that molding can be performed accurately and without buckling even if the female projection has a complicated shape, and the molding time is unnecessarily delayed. The moving speed of the lifting / lowering means is set to
It is good to set to 10 mm / min, preferably 3 to 5 mm / min. In this case, a detecting means for detecting an amount of movement of the fluid pressure urging means is provided, and the furnace temperature is set to 1700.
After reaching a temperature range of about 2,000 ° C. and detecting the deformation completion position of the quartz glass body by the detection means, the molding completion position is determined for a predetermined period of time, specifically, depending on the shape of the projection.
Hold for about 15 minutes, preferably 5 to 10 minutes, and wait for the deformation of the quartz glass body to be completed. Immediately after the completion of the molding, the female mold is returned in the returning direction via the fluid pressure urging means. By lowering the pressure and releasing the pressure, it is possible to prevent the reaction between the molding frame and the fused silica glass and prevent the protrusion during molding.
In addition, a hydraulic cylinder is used as the fluid pressure urging means in order to accurately maintain the deformation completion position and to enable accurate elevation control.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not merely intended to limit the scope of the present invention, but are merely illustrative examples unless otherwise specified. Absent.

First, a molding frame used in the present apparatus will be described.
FIG. 2 is an embodiment diagram showing the shape of the molding frame, and FIG.
In which the side plates 51 of the lateral boat 50 shown has disclosed a structure of a forming frame to pressure molding in, the female die 13 corresponding recesses 13 a are top and the projection 51a of the side plate 51 in FIG. (B) It is open to the side. That is, this molding frame is shown in FIG.
As shown in the figure, a concave portion 13a corresponding to the projection portion 51a with the quartz glass body 8 interposed therebetween is formed in a rectangular graphite frame forming a molding space composed of a graphite frame 15 made of dense graphite and a bottom plate 12. Female mold 1 with
3 and the pedestal 10 are arranged, and the outer shape of the pedestal 10 and the female mold 13 is made slightly smaller than the inner shape of the rectangular graphite frame 15 so that the width between the pedestal 10 and the female mold 13 can be reduced. You have set.

An arm-shaped relief portion 10a is provided at a predetermined position of the receiving table 10 corresponding to the concave portion 13a of the female mold 13, and the relief portion 10a has a volume equal to or slightly larger than the concave portion 13a of the female mold 13. Set to. And the female mold 13
The pedestal 10 is formed to be thick so as to withstand the compressive stress at the time of press load, and the graphite frame 15 is formed to be a thin rectangular frame so as to absorb heat well.

FIG. 3 is an embodiment showing another shape of the molding frame.
Quartz glass article of the present embodiment is provided with a protruding portion 56a as shown in FIG. (C), for example, functions as a flange 56 of the vertical furnace tube 55, the female mold 13 in FIG. (A) The recess 13a corresponding to the ring-shaped protrusion 56a is opened. Then, as shown in (A), the molding frame sandwiches the quartz glass body 8 in a cylindrical graphite frame forming a molding space composed of a graphite cylinder 15 and a bottom plate 12 made of dense graphite. The protrusion 56
The female die 13 having the concave portion 13a corresponding to the a and the receiving base 10 are arranged, and the width between the receiving base 10 and the female die 13 can be reduced. And the outer diameter of the female mold 13 is set slightly smaller.

The center column 16 is implanted in the female mold 13 in order to provide a center hole ( not shown) in the flange 56. The center hole 56d may be cut after completion of molding, and is always required. Not something.

[0030] Then the graphite making up the embodiments also female 13 and support 10 in any case, the gas permeability is 0.1 cm ² value of /sec(P:1.5Kgf/cm ²⁾ or more, preferably 0 It has a group of small gas permeation holes of about 0.9 cm ² / sec, and a bulk density of 1.5 g / cm.
² or less, preferably 1.24 g / cm ² , and a compressive strength of 1
00 kgf / cm ² or more, preferably 160 kgf / c
m ² before and after, the Shore hardness is preferably 10 or more around 15,
Flexural strength is 30 kg / cm ² or more, preferably 69 kg
/ Cm ² and the specific resistance is set to 40 μΩ · cm.

The purity of the graphite is Na,
0.1 ppm each of K, Li, Mg, Ca, Cu and Al
Hereinafter, Fe is set to 0.15 ppm or less, and is manufactured at a higher purity than at least the purity of quartz glass to be molded. The graphite material of the cradle 10 and the female mold 13 is formed by sintering or the like. In this case, the average particle size of the graphite is 30 to 100 μm, preferably 40 to 100 μm.
It is good to set to 100 μm.

On the other hand, the dense graphite constituting the graphite frame 15 and the bottom plate 12 has a bulk density of 1.77 to less.
1.90 g / cm ² , compressive strength is 700 to 1050 kg
f / cm ² , Shore hardness around 50-90, flexural strength 370-900 kg / cm ² , specific resistance 0.9-1.
Set to 8 μΩ · cm.

It is preferable that the center column 16 to be implanted in the female mold 13 is also formed of the same material as the female mold 13, but it is not always in contact during molding and heating, and is not necessarily limited.

Next, the basic configuration of a molding apparatus using the molding frame will be described. FIG. 1 discloses a basic configuration diagram of a quartz glass article molding apparatus according to the present invention.
The lower part is opened, and a graphite heater 2 for heating by an electromagnetic induction action of an electromagnetic induction heating coil 2 </ b> A arranged around the housing 1 is provided in a graphite housing 1 having a gate-shaped cross section. Numeral 2 is configured so that the power of the induction heating coil 2A is controlled by the thermometer and other control devices shown in FIG. 6, and the room temperature is controlled to the set temperature. The movable press rod 3 provided with a work table 3a at the upper end is made of graphite, and the lower end is connected to the piston portion 5a of the hydraulic cylinder 5, and moves up and down by driving the piston portion 5a via the load cell 3c. It is configured to be possible.

The molding frame 7 is placed on the work table 3a. The molding frame 7 is pressed upward by the drive of the hydraulic cylinder 5, but the upper surface of the receiving table 10 located above the molding frame 7 When the fixed press rod 19 comes into contact, the molding frame 7 is pressed from above and below.
Note that the fixed press bar 19 is formed of graphite and is fixed to the housing 1 integrally.

The load cell 3c disposed between the piston portion 5a of the hydraulic cylinder 5 and the movable press rod 3 is configured to measure the pressure during the pressing. A scale 4 is provided vertically on the side surface of the hydraulic cylinder 5 so that the pointer 3b extending horizontally from the side surface of the press rod 3 allows a user to check the distance of movement of the movable press rod 3. As a result, the amount of displacement of the movable press rod 3 pressed against the molding frame 7 can be visually recognized by observing the pointer 3b on the scale 4, and the completion of molding can be visually confirmed by confirming the rising position of the pointer 3b. .

The completion of the molding is detected by converting the movement amount of the pointer 3b into an electric signal such as a resistance change or a capacitor.
It is also possible to signal with a lamp or a buzzer. The lower entrance of the housing 1 is configured to be able to be closed by a shutter 6, and the shutter 6 is made of heat-resistant carbon felt. It can be opened and closed. After the shutter 6 is closed, the inside of the housing 1 can be replaced with an inert gas such as N ² or Ar or He by a device (not shown). The movable press rod 3, the hydraulic cylinder 5, and the scale 4 are integrally movable up and down so as to be able to enter and exit the housing 1 by a ball screw or other elevating means 35 described later in detail. After the opening of the work table 3a, the work table 3a is pulled out of the housing 1 through the elevating means 35, whereby the molding frame 7 can be replaced.

Next, a hot press apparatus according to an embodiment of the present invention based on the basic structure will be described with reference to FIG.
In this figure, the same symbols as those in FIG. 1 represent the same members.
Numeral 30 denotes a stainless steel molding furnace main body installed in a gate-shaped machine frame 34, and a water cooling jacket (not shown) is wrapped around the outer peripheral side, while an opaque quartz tube 3 is provided on the inner wall side of the furnace main body 30.
9, an induction heating coil 2A is disposed surrounding the
On the inner peripheral side of the heating coil 2A, a furnace space 42 is formed in which the upper surface and the side wall are surrounded by a heat insulating material 37 made of graphite and the lower part is opened.

The graphite heater 2 is disposed on the inner peripheral side of the side wall heat insulator 37, and is induction-heated by high-frequency electromagnetic induction between the graphite heater 2 and the induction heating coil 2A. As described above, the heater 2 is configured such that the power of the induction heating coil 2A is controlled by a thermometer 33 or the like outside the furnace, and the room temperature is controlled to the set temperature. On the axis of the heat insulating material 37 on the upper surface side, a fixed press rod 19 made of graphite penetrates downward toward the furnace space 42, and the upper part of the press rod 19 is a heat insulating material 3.
7 protrudes upward. The press rod 19 is used for the machine frame 3.
The fixed press rod 19 is always fixed at a predetermined position even if it receives a hydraulic pressure via the receiving table 10 by raising the work table 3a.

On the other hand, the movable press rod 3 made of graphite, the water-cooled rod 5a corresponding to the piston of the hydraulic cylinder 5, and the water-cooled rod 5a Load cell 3
Hydraulic cylinders 5 are vertically connected to each other via c, and are connected to a nut portion 35a of a ball screw 35c via a holding frame 36.

The ball screw 35c is provided vertically along the vertical leg 34a of the machine frame 34 in parallel with the direction in which the hydraulic cylinder 5 moves forward and backward.
By rotating the hydraulic cylinder 5, the hydraulic cylinder 5 is vertically moved up and down via the screwed nut portion 35a and the holding frame 36.

A scale 4 is vertically attached to the side surface of the vertical leg 34a of the machine frame 34, and the holding frame 36 is raised in an L shape along the scale 4, and the scale 4 is attached to the rising portion 36a. There is provided a pointer 3b to be fitted to the.

The shutter 6 comprises an upper shutter 6A made of a graphite plate (single-layer graphite) and a lower shutter 6B formed by laminating a quartz glass plate and a graphite plate (laminated graphite). , So that it can move forward and backward along the horizontal direction. That is, the upper shutter 6A moves horizontally along the lower surface of the heat insulating material 38 so as to close the furnace space 50, while the lower shutter 6B moves horizontally along the lower surface of the furnace body 30 so as to close the furnace body 30. It is configured to be movable. Each of the shutters 6A and 6B is fitted around the axis of the movable press rod 3, so that the movable press rod 3 can be moved up and down even after the shutter is closed.

Next, a molding operation based on the above apparatus will be described. 6, the upper shutter 6A and the lower shutter 6b are opened by driving the air cylinder 32, and the motor 35
b, the movable press rod 3, the hydraulic cylinder 5, and the holding frame 36 are integrally lowered by rotating the ball screw 35c, and the work table 3a is lowered to a position outside the furnace.
As shown in FIGS. 2, 4A and 3A, the molding frame 7 on which the quartz glass body 8 is placed is placed on the work table 3a, and the work table 3 is rotated in the reverse direction by the ball screw 35c. 3 a is raised into the furnace space 50, and is raised to a position where the upper surface of the pedestal 10 is almost in contact with the fixed press rod 19. In this state, the hydraulic cylinder 5 applies 0.03 mm to the quartz glass body 8 via the bottom plate 12 and the female mold 13.
A pressing pressure of 0.04 Kgf / cm ² is applied. Then, after closing the upper shutter 6A and a lower shutter 6B by the driving of the air cylinder 32, the air-tight state is formed on the inside and outside of the furnace body 30 is set to approximately 1 atmosphere replaced with an inert gas N ^2.

Then, while heating the graphite heater 2 through the dielectric heating coil 2A and measuring the temperature rising time with the thermometer 33, the heating rate of the furnace space was increased to 35 to 55 ° C. /
min, preferably at a temperature of 45 to 50 ° C./min, heat deformation starts at about 1650 ° C., followed by a hydraulic cylinder for maintaining a press pressure of 0.03 to 0.04 kgf / cm ^2. Perform a rise of 5. The ascending speed in this case is 2 to 10 mm / min, preferably 3 to 5 mm / min while measuring with the pointer 3 b / scale 4.
It rises at a constant speed of min. The pointer 3b / scale 4 may be attached to the hydraulic cylinder 5 as shown in FIG.

Then, the needle 3b / scale 4 rises to the top dead center (maximum rising position) of the female mold 13 and the temperature rises to a molding temperature of 1850 ° C. to 1960 ° C. to complete predetermined molding. , 5 min to 10 mi at that position
The n position is held. Note that the amount of movement (movement stroke amount) up to the maximum ascending position is calculated in advance. In the molding state, as shown in FIG. 4, gases such as CO, CO ² , SiO ² , and SiC generated by the reaction between the quartz glass body 8 and the graphite molding frames 10 and 13 are indicated by arrows. As described above, the air escapes into the furnace space 50 through the ventilation part of the receiving stand 10 and the ventilation part of the female mold 13. At this time, female type 1
In order to make the escape from the ventilation section 3 more efficient, a large number of through holes 12a may be formed in the bottom plate 12, or the female mold 13 may be used as the bottom plate 12 without providing the bottom plate 12. .

Since the press pressure is applied even during the position holding time, the scale of the scale 4 indicated by the pointer 3b slightly rises. Therefore, by observing the rising speed of the pointer 3b, the scale is automatically measured. Thus, the completion of the deformation of the quartz glass body 8 can be detected. After the position is held, the pointer 3b indicating the scale of the scale 4 is watched, and when the completion of the displacement of the quartz glass is detected based on an algorithm made by calculating the displacement in advance, the hydraulic cylinder 5 is lowered to reduce the pressure. To release.

After releasing the pressure, the shutter 6 is opened,
The work table 3a is lowered by the elevating means 35 such as the ball screw 35c, the molding frame 7 is taken out of the table 3a in a heated state, the high-temperature mold is moved to a cooling table (not shown), and the quartz The lid is covered with a cap 23 to prevent oxidation of graphite. Thereafter, after performing deburring and predetermined cutting, the process proceeds to an annealing process, and after holding at 1150 ° C. for 30 minutes, gradually cooling and performing a predetermined annealing process to complete a molded product.

On the other hand, the next molding frame 7 is placed on the work table 3A after moving to the cooling table, and molding is performed in the same procedure as described above. After the second time, the temperature in the furnace is
Almost 1500 ° C to 1600 ° C already close to glass melting temperature
Since the preload starting temperature is maintained before and after,
The temperature is about 00 ° C. to 1600 ° C., but in any case, the heating softening start temperature of the quartz glass body 8 is preferably 1600 ° C. to 1650 ° C. or less.

By the way, as for the material of the quartz glass, experimental results slightly different from those of the oxyhydrogen-melted product and the electro-melted product have been found. The conditions for molding the quartz glass article, which are good in both cases, are as follows: the first heating rate is 46.5 ° C./m
in, the second time was almost the same as 129 to 183 ° C./min. However, regarding the other data, the oxyhydrogen molten product had a melting press temperature of 1860 ° C., a holding time of 5 min, a deformation speed of 4 mm / min, Press pressure: 0.03 kg / c
m ² , and the melting temperature of the electromelted product is 1950
° C, holding time: 10 min, deformation speed: 3 mm / mi
n, the pressing pressure was 0.04 kg / cm ² , whereby a good molded quartz glass article could be obtained.

According to this embodiment, a high-precision molding process is performed by applying a pressing pressure to the female mold 13 and setting the pressing pressure to a minute pressure in the range of 0.01 to 0.1 kgf / cm ^2. And the contact area between the quartz glass body 8 and the graphite can be reduced as much as possible.

The pressing pressure is preferably pre-pressed from a temperature range before the quartz glass body 8 softens and deforms, that is, from a temperature before 1600 ° C., and the deformation speed of the glass is determined by the pressing pressure and / or the glass melting temperature. Although different, as a result of experiments, it is preferably from 0.07 mm / min to 8 mm / min, more preferably from 0.07 mm / min to 5 mm / min.
The reason for such variation is that in the case of continuous operation, the deformation speed of the glass is increased by 10 times or more in the second and subsequent times where the preheating is present as compared with the first time when the temperature is raised from room temperature. This is because the temperature in the furnace is already maintained at around 1500 ° C. to 1600 ° C., which is close to the glass melting temperature, after the second time. In addition, the reason why the temperature in the furnace is maintained in this way is that high heat can be maintained in the molding space because the inlet side of the housing 1 is set to the lower side.

Further, since the female mold 13 and the pedestal 10 which are always in contact with the quartz glass body 8 at the time of pressure molding are made of a material having air permeability, the quartz glass and the graphite react with each other. CO, C generated by
Gases such as O ² and SiC can easily escape out of the molding space. In addition, the fact that gases such as CO, CO ² , and SiC can easily escape to the outside of the molding space prevents silicon carbide from being formed on the glass surface, and furthermore, cracks occur after cooling due to differences in thermal expansion. In addition to eliminating the drawback that the yield is deteriorated, it is possible to eliminate the disadvantage that the slip between the mold and the glass due to the adhesion of silicon carbide is deteriorated and the glass does not enter the details of the mold.

In a device for molding a quartz glass article having a projection 51a on one flat surface side, by applying a pressing pressure from the back side of the female mold 13, the softened quartz glass easily flows into the recess 13a. However, if such a configuration is adopted, the side facing the pedestal 10 located on the back side of the recess 13a, 13c is recessed by the flow, so that who is formed.

Therefore, a relief portion 10a is provided at a predetermined position of the receiving base 10 corresponding to the concave portion of the female mold 13, more specifically, a relief portion 10a set to have a volume equal to or slightly larger than the concave portion of the female mold 13. By forming and forming the soft quartz glass while collecting the softened quartz glass, the formation of the dent on the side facing the pedestal 10 can be prevented. In this case, the escape portion 1
0a becomes a convex after the completion of molding, but it may be cut later by cutting.

[0056]

As described above, according to the present invention, even when a quartz glass article having a projection is machined, a quartz glass article which can be molded with high precision can be manufactured, and continuous molding is easy. This is extremely practical because it can be performed in And so on.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for heat-forming a quartz glass body according to an embodiment of the present invention.

2A is a cross-sectional view of a molding frame, and FIG. 2B is a perspective view showing the molded product, and particularly relates to a side plate of a horizontal boat shown in FIG.

3A is a cross-sectional view of a molding frame, FIG. 3B is a perspective view showing the molded product, and particularly relates to a flange portion of a furnace core tube shown in FIG.

FIG. 4 shows a pressed state of the molding frame of FIG. 2;

FIG. 5 shows a state in which a quartz cap is attached to the molding frame of FIG. 2;

FIG. 6 is a detailed view of a hot press apparatus according to an embodiment of the present invention based on the basic configuration of FIG.

[Explanation of symbols]

 2, 2A Induction heating means 3a Work table 3C Pressure detection means 5 Fluid pressure urging means 6A Upper shutter 6B Lower shutter 7 Molding mold 8 Quartz glass body 13 Female mold 15 Graphite frame 19 Support (fixed press rod) 35 Elevation Means 35c to 35A Ball screw mechanism 50 Space in the furnace

Continuing from the front page (72) Inventor Hiroshi Kimura 2-13-60 Kitafu, Takefu-shi, Fukui Prefecture Inside the Takefu Plant, Shinetsu Quartz Co., Ltd. (72) Inventor Koichi Taniyama 3rd-1 Kadani-cho, Takefu-shi, Fukui Prefecture No. 4 Fukui Shin-Etsu Quartz Co., Ltd. (72) Inventor Nokazu Fujii No. 3 Kayaya-cho, Takefu-shi, Fukui Prefecture No. 4, No. 4 Shin-Etsu Quartz Fukui Co., Ltd. (56) References JP-A-5-17174 (JP, A) JP-A-57-92528 (JP, A) JP-A-5-193959 (JP, A) JP-A-5-221668 (JP, A) JP-A-5-345624 (JP, A) (58) (Int.Cl. ⁷ , DB name) C03B 23/049 C03B 11/00 C03B 20/00

Claims (6)

(57) [Claims] (1)Molding space with graphite frame around
The protrusions on the lower surface side with the quartz glass body housed in
And the corresponding female mold, and the pedestal of the glass body on the top side
Furnace space around the heating element
And place the quartz glass body at a high temperature through a mold
Quartz glass object which is molded under pressure under heating and has projections on the flat side
In an apparatus for manufacturing products, The female mold and the pedestal are not made of graphite material.
Molding formwork, A support that fixedly supports the cradle on the upper surface side, On the other hand, it is arranged at a lower position facing the support,
A work table on which the formwork is placed; The work table is raised and lowered into the furnace from a lower position outside the furnace
Lifting means, Fluid pressure biasing means continuously provided below the work table
When, The The above-mentioned menu is provided by a hydraulic cylinder constituting a fluid pressure urging means.
Speed while moving the die in the pressing direction.
m / min, made of quartz glass articles
Manufacturing equipment. (2)Molding space with graphite frame around
The protrusions on the lower surface side with the quartz glass body housed in
And the corresponding female mold, and the pedestal of the glass body on the top side
Furnace space around the heating element
And place the quartz glass body at a high temperature through a mold
Quartz glass object which is molded under pressure under heating and has projections on the flat side
In an apparatus for manufacturing products, The female mold and the pedestal are not made of graphite material.
Molding formwork, A support that fixedly supports the cradle on the upper surface side, On the other hand, it is arranged at a lower position facing the support,
A work table on which the formwork is placed; The work table is raised and lowered into the furnace from a lower position outside the furnace
Lifting means, Fluid pressure biasing means continuously provided below the work table
When, The Detecting means for detecting the amount of movement of the fluid pressure urging meansWhenSet
The temperature in the furnace reaches a temperature range of about 1700 to 2000 ° C.
And the completion of the deformation of the quartz glass body by the detecting means.
After detecting the position, the molding completion position was held for a predetermined time.
Thereafter, the female die is moved in the return direction via the fluid pressure urging means.
Quartz glass article manufacturing equipment characterized in that it is configured to be movable.
Place. 3. The upper surface of the pedestal is fixed to the support by the raising and lowering means, and then the fluid pressure urging means is applied under a high-temperature heating while applying a small pressing force to the quartz glass body via a female mold by a female mold. 3. The apparatus for manufacturing a quartz glass article according to claim 1, wherein the apparatus is formed by pressing. 4. The apparatus for manufacturing a quartz glass article according to claim 1, wherein the glass body housed in the mold is configured to be capable of generating heat by induction heating means. 5. The fluid pressure urging means is constituted by a hydraulic cylinder via a pressure detecting means, and the pressure detecting means reduces a small pressing force applied to the softened quartz glass body via the female die by 0.01. 4. The apparatus for manufacturing a quartz glass article according to claim 3, wherein the apparatus is configured to be controllable in a range of 0.5 kgf / cm ² to 0.5 kgf / cm ^2. 6.Molding space with graphite frame around
The protrusions on the lower surface side with the quartz glass body housed in
And the corresponding female mold, and the pedestal of the glass body on the top side
Furnace space around the heating element
Placed through the mold for moldingHigh temperature quartz glass body
Quartz glass object which is molded under pressure under heating and has projections on the flat side
In an apparatus for manufacturing products,Said The female mold and the cradle are made of porous graphite material,
Each of the graphite frames is made of dense graphite material
A support for fixing and supporting the cradle on the upper surface side; and
Work table on which a work form is placed, and the work table is raised and lowered into the furnace from a lower position outside the furnace
Elevating means, fluid pressure urging means continuously provided below the worktable
When, Said Open the lower part of the furnace space surrounded by the heating element,
In the mouth, the work table can enter the furnace,
Openable and closable via two shutters made of light-sensitive material
A quartz glass article manufacturing apparatus characterized by the following.