JP4184468B2 - Manufacturing method of quartz glass container - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  In the present invention, quartz glass is pressure-molded under high temperature heating to produce quartz glass.containerProducing quartz glasscontainerIn particular, quartz in which a quartz glass lump is placed between a male mold and a female mold, and the quartz glass lump is pressure-molded into a shape different from that before molding under high-temperature heating. GlasscontainerIt relates to the manufacturing method.
[0002]
[Prior art]
  Conventionally, when manufacturing a quartz glass member with a complex shape, a quartz glass welding rod is heated on a quartz glass flat plate by a burner, and after being melted, the cladding is ground and the predetermined shape is obtained by grinding In addition, it was manufactured by molding into a block or cutting out from a block material of quartz glass.
  However, in the process of overlaying with a welding rod, the work time is very long, and if the welding speed and heating temperature are not adjusted properly, bubbles will be trapped. However, it had a problem that workability was poor because it was fire processing. Further, in the cutting process of the block material, there are problems that the material basic unit is large and that the grinding process takes a long time.
[0003]
  In order to eliminate this drawback, a method of heat-molding a quartz glass plate material with a male mold and a female mold is known from Japanese Patent Application Laid-Open No. 8-295522.
  This technology places a quartz glass plate on a female mold, heats it to 1400-1600 ° C., which is the bending processing temperature, and press-molds the heated quartz glass plate with a male mold for about 30 minutes to 4 hours to form a dome-shaped quartz. A glass container is manufactured.
[0004]
  Then, assuming that the mouth outer diameter, which is the dome-shaped opening, is R, and the narrowing height is P, R1 / P1 = 375 mm / 120 mm = 3.12, R2 / P2 = 390 mm / 140 mm = 2. A quartz glass container having a squeezing height P of about 1/3 of the opening outer diameter R can be obtained.
[0005]
[Problems to be solved by the invention]
  However, while the softening point temperature at which the quartz glass becomes soft and stretches is about 1700 ° C., according to the prior art, the quartz glass plate material is press-molded at a bending temperature of 1400-1600 ° C., It is very difficult to mold a quartz glass container exceeding the narrowing height P of about 1/3 of the outer diameter R of the opening, or a quartz glass container having a shape whose curvature does not change monotonically from the dome-shaped side surface to the bottom surface. It is.
[0006]
  In particular, in the case of a quartz glass container having a shape in which the curvature does not change monotonously in the latter case, it is necessary to separately prepare the previous part from the curvature variation point and weld it by the split molding method, which increases the number of manufacturing steps. At the same time, accurate machining becomes difficult.
[0007]
  In view of the above-mentioned conventional drawbacks, the present invention is a quartz glass that can improve the flow of glass, has a high squeezing height, and can be molded with high accuracy.containerAn object of the present invention is to provide a method for producing the above.
[0008]
[Means for Solving the Problems]
  In the present invention, a quartz glass lump is sandwiched between a male mold and a female mold and pressure-molded under high temperature heating to produce quartz glass.containerProducing quartz glasscontainerIn the manufacturing method of
  The male and female molds have a gas permeability of 0.1 cm. ² / Sec (P: 1.5Kgf / cm ² Value)) is formed using porous graphite having air permeability above,
  The total surface area M of the quartz glass block which is placed between the male mold and the female mold and is pressure-molded, and the quartz glass to be moldedcontainerThe total surface area N of N / M = 2 or more, and
  The projected area S (cm) of the surface perpendicular to the pressing direction between the male mold and the female mold²) And wall thickness T (mm), T / S = 0.05 (mm / cm²) The quartz glass sandwiching the quartz glass block having the above relationshipcontainerAnd when the quartz glass block reaches a temperature range of 1700 ° C. to 2000 ° C., the quartz glass block is switched from pressing by the weight of the male mold and the female mold to forced pressing,
  Quartz glass formed by the male mold and female moldcontainerHowever, the relationship between the diameter D corresponding to the outer diameter of the opening on one side and the height H from the closed bottom on the other side to the front surface of the opening is D / H = 2.6 to 0.7. Quartz glass withcontainerIt is characterized by manufacturing.
[0009]
  Here, the quartz glass block is, for example, as shown in FIG. 2, the projected area S (cm on the surface orthogonal to the pressing direction).²) And thickness T (mm), T / S = 0.05 (mm / cm²) Say the above. And a quartz glass lump as a processing raw material (regardless of the shape of a prism (block etc.), a cylinder (rod etc.), a cylinder (cylinder etc.), a tube (tube etc.), a square plate (plate etc.), a disc etc. Ingot etc.).
[0010]
  The invention according to claim 1 is characterized in that the quartz glass block is placed between a male mold and a female mold, and is melted and pressed under high temperature heating. There is no need to re-melt or cut an ingot produced by a flame melting method, an electric melting method, a plasma melting method, a direct synthesis method or the like into a plate shape having a necessary thickness.
[0011]
  Further, a quartz glass body obtained by vitrifying a porous base material does not need to be remelted to form a plate having a required thickness, and the quartz glass body has a required volume. What is necessary is just to press-mold the quartz glass lump under high temperature heating.
  The quartz glass block may be one piece or plural pieces.
[0012]
[0013]
[0014]
  The present invention relates to the total surface area M of the quartz glass block that is placed between the male mold and the female mold as described above and is pressure-molded, and the quartz glass to be molded.containerSince the total surface area N is formed so as to have a relationship of N / M = 2 or more, a complicated shaped quartz glass container having a deep bottom can be easily formed.
[0015]
[0016]
  Since the quartz glass block is heated at 1700 ° C. to 2000 ° C. in this way, it melts to lower its viscosity and its fluidity increases, and the molten quartz glass is pressurized by its own weight between the male mold and the female mold. Since the pressure is from 5 to 100 kgf by hydraulic pressure, the quartz glass fluid can flow to the corner of the mold, and a quartz glass container having a complicated shape can be manufactured with high accuracy.
[0017]
[0018]
[0019]
[0020]
  Said inventionHowever, when the temperature at which the quartz glass block melts is reached, the contact area between the male mold and the fused quartz glass block fluid changes so that the pressure increases so that the male mold is pressurized. When the position is no longer displaced, the quartz glass fluid flows into the corners of both molds by further pressurizing and holding, and the molding process can be performed with higher accuracy.
[0021]
  The rate of temperature rise to the quartz glass block is 35 to 55 ° C./min (preferably 40 to 50 ° C./min), and the moving speed of the mold by the male mold or female mold is 2 to 10 mm / min (preferably 3 to 5 mm / min) is also an effective means of the present invention.
[0022]
  By setting the heating rate and the moving speed of the mold as described above, even if the shape of the mold is complex, the buckling does not occur accurately and the molding time is unnecessarily delayed. And can be molded without any problem.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Not too much.
[0024]
  First, the molding frame used in this embodiment will be described.
  FIG. 1 is a diagram showing an embodiment of the shape of a molding frame. A molding frame 7 for pressure-molding a quartz glass container 16 having a flange 16a at the opening of the dome-shaped portion 16b shown in FIG. The structure is disclosed.
  That is, this molding frame is a male frame made of porous carbon with a quartz glass block 15 sandwiched in a rectangular graphite frame that forms a molding space composed of a graphite frame 11 made of dense graphite and a bottom plate 12. The mold 13 and the female mold 14 are arranged so that the width between the male mold 13 and the female mold 14 can be reduced. The outer dimensions of the male mold 13 and the female mold 14 are slightly smaller than the inner dimension of the rectangular graphite frame 11. It is set to small.
[0025]
  The concave portion 14c of the female die 14 and the corresponding convex portion 13c of the male die 13 are formed with curved surfaces having the same curvature, and the lower surface 13a of the collar portion of the male die 13 and the upper surface 14a of the female die 14 are in contact with each other. In this case, between the lower surface 13a of the collar portion of the male mold 13 and the stepped portion 14b of the female mold 14, and between the curved surface 13d of the convex section 13c of the male mold 13 and the curved surface 14d of the concave section 14c of the female mold 14. Is formed such that a predetermined gap is formed.
  The male mold 13 and the female mold 14 are formed to be thick enough to withstand the compressive stress during the press load, and the graphite frame 11 is formed from a thin rectangular frame so as to absorb heat.
  Although the female mold 14 is disposed below and the male mold 13 is disposed above, it goes without saying that the female mold 14 may be disposed above and the male mold 13 may be disposed below.
[0026]
  In this way, quartz glass is sandwiched between a male mold and a female mold surrounded by a graphite frame.containerIn the method of molding, as shown in FIG. 1, the male mold and the female mold are always in contact with the quartz glass body at the time of pressure molding.₂SiC vapor is generated.
  When the temperature is raised to 1900 ° C., the viscosity of the quartz glass is greatly reduced, and the molded quartz glasscontainerThe surface of the surface will be uneven.
  Therefore, it is necessary to consider gas escape routes.
  Therefore, in the present embodiment, a male mold and a female mold are formed using porous graphite in which the graphite material itself has air permeability such as sintered graphite.
  In this case, the gas permeability is preferably 0.1 cm.²/ Sec (P: 1.5Kgf / cm²Value) or more, more preferably 0.9 cm²Both molds and bottom plate 12 having minute gas permeation hole groups of about / sec are used.
[0027]
  The bulk density of the porous graphite material is 1.5 g / cm.³The following graphite material may be used, but if the bulk density is too low, breakage or deformation occurs during pressure molding. Therefore, preferably 1.2 ± 0.2 g / cm³It is good to set to.
  In addition, the compressive strength is 100Kgf / cm for accurate molding without causing damage or deformation during pressure molding.²Or more, preferably 150 to 600 kgf / cm², Shore hardness is 10 or more, preferably around 15 ± 2, bending strength is 30 kgf / cm²Or more, preferably 69 kgf / cm²Before and after, it is necessary to set the specific resistance to 40 μΩ · cm.
[0028]
  On the other hand, since both molds are always in contact with the quartz glass block at the time of pressure molding, if there is an impurity on the graphite side due to contact, a semiconductor poison or cristobalite layer is proportionally formed on the surface of the quartz glass body. Is formed, which also causes devitrification and cracks.
  Therefore, it is preferable to set the metal elements which cause the semiconductor poison such as Na, K, Li, Ca, Mg and Fe and the cristobalite layer to 0.1 to 0.2 ppm or less, respectively.
[0029]
  FIG. 2 shows a quartz glass block used in the present embodiment. The glass block is not a plate material, and the relationship between the thickness T and the projected area S is T / S (mm / cm²) = 0.05 (mm / cm²2) The block 5A shown in FIG. 2A is a block in which the surface having the projection area S1 with respect to the thickness T1 has a flat surface or irregularities, or is formed in a wave pattern. FIG. 2B shows a block formed into a spherical or hemispherical shape having a projected area S2 with respect to the thickness T2 or a lump having a bulge.
  The mass is the T / S (mm / cm²) = 0.05 (mm / cm²), A cylinder, a prism, or any other appropriate shape may be used.
[0030]
  And the purity of the graphite is set to 0.1 ppm or less for Na, K, Li, Mg, Ca, Cu, and Al, respectively, and Fe is set to 0.15 ppm or less, which is at least higher than the purity of quartz glass to be molded. Manufactured by. The graphite material of the male mold 3 and the female mold 4 is formed by sintering or the like. In this case, the average particle diameter of the graphite is set to 30 to 100 μm, preferably 40 to 100 μm.
[0031]
  On the other hand, the dense graphite constituting the graphite frame 11 and the bottom plate 12 has a bulk density of 1.77 to 1.90 g / cm.²Compressive strength is 700-1050Kgf / cm², Shore hardness is around 50-90, bending strength is 370-900kg / cm²The specific resistance is set to 0.9 to 1.8 μΩ · cm.
[0032]
  As described above, in order to perform accurate molding, it is necessary to perform high-temperature heating at 1700 to 2000 ° C.
  However, when high-temperature heating is performed, as described above, the reaction between graphite and quartz glass causes CO and CO₂And even SiO₂Evaporating gas is generated, and quartz glass bubbles are generated, and cracks and devitrification occur.
  Such countermeasures are taken from both the molding frame and the molding pressure device.
[0033]
  Next, we will consider from the aspect of molding.
  In this process, as described above, by setting the heating temperature to 1700 to 2000 ° C., preferably 1840 to 1980 ° C., the viscosity becomes low and the molding can be facilitated.
  In this case, in the case of natural quartz glass produced with an oxyhydrogen flame, the heating temperature is set to 1840-1900 ° C., and in the case of natural quartz glass produced by the electric melting method, the heating temperature is set to 1900-1960 ° C.
[0034]
  In this case, the molding may be performed without applying pressure. However, if the pressing is performed without applying 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 reaction gas cannot be suppressed.
  Therefore, in the present embodiment, the contact time and the contact area between the forming frame and the fused silica glass in the high temperature heating region are set to be minimized.
  In addition, it is necessary to devise an apparatus capable of facilitating continuous molding.
[0035]
  Therefore, in the present embodiment, a support body that fixes and supports the male mold on the upper surface side, a work table that is disposed at a lower position facing the support body, and on which the molding frame is placed, and the work table The molding apparatus is composed of a lifting / lowering means for raising and lowering the inside of the furnace from the furnace preliminary chamber at a position outside the furnace and a fluid pressure urging means continuously provided below the work table.
[0036]
  Next, a basic configuration of a molding apparatus using the molding frame will be described.
  The molding frame is disposed in a molding apparatus described later, and the molding apparatus has a resistance heating type or induction heating type electric furnace, and the furnace is pressure-molded in an inert gas atmosphere in order to prevent oxidation of graphite. Processing is configured to be performed.
  Further, a furnace preliminary chamber for inserting a workpiece is provided, and the quartz glass block is configured to be able to be conveyed into the furnace through the preliminary chamber.
  Further, the press control is performed by measuring the temperature inside the furnace, the amount of displacement, which is the amount of contraction in the thickness direction of the ingot, and controlling the press load, the press time, and the like.
[0037]
  This will be specifically described below.
  FIG. 5 shows the quartz glass of this embodiment.containerA basic configuration diagram of a molding apparatus is disclosed, in which a lower part is opened, and an electromagnetic induction heating coil 2A arranged around the casing 1 is disposed in a graphite casing 1 having a gate-shaped cross section. A graphite heater 2 for heating by electromagnetic induction is provided, and the heater 2 is configured such that the induction heating coil 2A is power-controlled by a thermometer and other control devices shown in FIG. 6, and the room temperature is controlled to a set temperature. Has been.
  The movable press bar 3 provided with a work table 3a at the upper end is made of graphite, the lower end is connected to the piston part 5a of the hydraulic cylinder 5, and is moved up and down by driving the piston part 5a through the load cell 3c. It is configured to be possible.
[0038]
  The molding frame 7 is placed on the work table 3a, and the molding frame 7 is pressed upward by driving the hydraulic cylinder 5, but the upper surface 13b of the male mold 13 positioned above the molding frame 7 is fixed. When the press bar 19 comes into contact, the molding frame 7 is pressed from above.
  The fixed press bar 19 is made of graphite and is fixed integrally to the housing 1.
[0039]
  A load cell 3c disposed between the piston portion 5a of the hydraulic cylinder 5 and the movable press rod 3 is configured to be able to measure the pressure during the pressing.
  Further, a scale 4 is erected vertically on the side surface of the hydraulic cylinder 5 so that the ascending distance of the movable press rod 3 can be confirmed by a pointer 3b extending horizontally from the side surface of the press rod 3.
  As a result, the amount of pressing displacement of the movable press bar 3 to the molding frame 7 can be visually confirmed by observing the pointer 3b on the scale 4, and the ascending position of the pointer 3b can be confirmed to visually confirm the completion of molding. .
[0040]
  This molding completion detection can also be signaled by a lamp or buzzer by converting the amount of movement of the pointer 3b into an electrical signal such as a resistance change or a capacitor.
  The lower entrance of the housing 1 is configured to be closed by a shutter 6, and the shutter 6 is formed of a heat-resistant carbon felt, and extends along the lower surface of the housing 1 by an air cylinder (not shown). And can be opened and closed.
  The movable press bar 3, the hydraulic cylinder 5 and the scale 4 are configured so as to be integrally movable up and down so as to be able to enter and withdraw the interior of the housing 1 by a ball screw and other elevating means 35 described in detail later. After opening, the molding frame 7 can be exchanged by lowering them through the lifting means 35 and withdrawing the work table 3 a out of the housing 1.
[0041]
  Next, a quartz glass lump heat molding apparatus according to the present embodiment based on the basic configuration will be described with reference to FIG. In the figure, the same reference numerals as those in FIG. 5 denote the same members.
  30 is a stainless steel molding furnace main body installed in a gate-shaped machine casing 34, and a water cooling jacket (not shown) is provided on the outer peripheral side, while an opaque quartz cylinder 39 is provided on the inner wall side of the furnace main body 30. An induction heating coil 2A is disposed around the inner periphery of the heating coil 2A, and a furnace space 42 is formed on the inner peripheral side of the heating coil 2A. ing.
[0042]
  And the graphite heater 2 is arrange | positioned at the inner peripheral side of the said side wall heat insulating material 37, and is induction-heated by the high frequency electromagnetic induction between the said induction heating coils 2A. As described above, the heater 2 is configured such that the induction heating coil 2A is controlled in power by the thermometer 33 or the like outside the furnace, and the room temperature is controlled to the set temperature.
  A fixed press rod 19 made of graphite is penetrating and penetrating toward the furnace space 42 on the axis of the heat insulating material 37 on the upper surface side, and the upper portion of the press rod 19 projects above the heat insulating material 37. ing.
  The press bar 19 is fixed by a machine frame 34, and the fixed press bar 19 can always be held at a predetermined position even if the work table 3a is lifted to receive hydraulic pressure through the male mold 13.
[0043]
  On the other hand, on the lower side of the work table 3a facing the fixed press rod 19 through the furnace space 42, the above-mentioned graphite-made movable press rod 3, the water-cooled rod 5a corresponding to the piston portion of the hydraulic cylinder 5, and the load cell 3c are provided. The hydraulic cylinders 5 are vertically connected to each other, and these are connected to the nut portion 35 a of the ball screw 35 c via the holding frame 36.
[0044]
  The ball screw 35c is suspended along the vertical leg 34a of the machine frame 34 in parallel with the advancing and retreating direction of the hydraulic cylinder 5. The ball screw 35c is rotated by the motor 35b to be screwed into the nut portion 35a and The hydraulic cylinder 5 is raised and lowered vertically through the holding frame 36.
[0045]
  A scale 4 is vertically mounted on the side surface of the straight leg 34a of the machine frame 34. The holding frame 36 is raised in an L shape along the scale 4, and the scale 4 is fitted to the rising portion 36a. A pointer 3b is provided.
[0046]
  The shutter 6 includes 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), and these are integrally formed by an air cylinder 32 in the horizontal direction. It is configured to be able to advance and retreat along.
  That is, the upper shutter 6A moves in the horizontal direction along the lower surface of the heat insulating material 37 so that the furnace body 30 can be closed, whereas the lower shutter 6B moves in the horizontal direction along the lower surface of the frame 51 so as to close the furnace space 50. It is configured to be movable.
  The shutters 6A and 6B are both fitted around the axis of the movable press bar 3, and the movable press bar 3 can be moved up and down even after the shutter is closed.
  The work table 3a is provided with an open / close door (not shown) through which the quartz glass block 15 can be taken in and out at the lowering stop position. The work table 3a is airtightly provided outside when the open / close door is closed. It is configured to be located in a connected furnace preliminary chamber (not shown).
[0047]
  Next, the molding operation based on the above apparatus will be described.
  In FIG. 6, the upper shutter 6A and the lower shutter 6B are opened by driving the air cylinder 32, and the movable press rod 3, the hydraulic cylinder 5 and the holding frame 36 are lowered integrally by rotating the ball screw 35c by the motor 35b. After lowering the table 3a into the furnace preparatory chamber outside the furnace, the upper and lower shutters are closed, and the molding furnace 30 is preheated to 1500 ° C. in advance.
[0048]
  Next, as shown in FIG. 1, the molding frame 7 on which the quartz glass block 15 is placed is placed on the work table 3a, the open / close door is closed, and the preliminary chamber is evacuated by a vacuum pump, and the inert gas is removed. To the atmospheric pressure.
  Then, the shutter is opened, and the work table 3a is moved through the furnace space 50 into the furnace body 30 by the reverse operation of the ball screw 35c, and the upper surface 13b of the male mold 13 is substantially in contact with the fixed press rod 19. Until the shutter is closed.
[0049]
  In this state, heating is performed to a molding temperature of 1940 ° C. At this time, the heating rate to the quartz glass block is 35 to 55 ° C./min (preferably 40 to 50 ° C./min).
  At this time, since the tip of the male convex portion 13c comes into contact with the quartz glass block and its own weight is applied, as the temperature rises and the quartz glass block melts, it is pushed by the dead weight of the male mold 13 and is male. 13 drops, but when it exceeds 1800 ° C., the hydraulic cylinder 5 applies a molding load of 20 kgf.
[0050]
  While gradually increasing from this load, it is desirable that the moving speed of the mold by the male mold is set to 2 to 10 mm / min (preferably 3 to 5 mm / min).
  By pressurizing with a mold as described above, bubbles are not entrained, and even if the shape of the mold is complex, it does not cause buckling with high accuracy, and the molding time is unnecessarily delayed. It can be made possible without molding.
[0051]
  Heat deformation starts at around 1650 ° C., and the rising speed of the hydraulic cylinder 5 is increased at a constant speed of 2 to 10 mm / min, preferably 3 to 5 mm / min while measuring with the pointer 3b / scale 4.
  The pointer 3b / scale 4 may be attached to the hydraulic cylinder 5 as shown in FIG.
[0052]
  Then, the needle 3b / scale 4 moves up to the top dead center (maximum ascending position) of the female die 13, and the male collar lower surface 13a and the female upper surface 14a come into contact with each other, and the amount of displacement of the glass fluid Finally, when a load of 80 kgf is applied and held for about 10 minutes, the glass fluid is made to flow to the details, and the process ends. Total press time is about 120 minutes.
  The amount of movement up to the maximum ascending position (movement stroke amount) is obtained in advance by calculation.
  In the molding processing state, the quartz glass block 15 reacts with the male mold 13 and the female mold 14 which are graphite molding frames to generate CO, CO₂, SiC₂The gas such as SiC escapes into the vent portion furnace body 30 of the male mold 13.
  At this time, in order to escape from the vent portion of the female 14, a large number of through holes may be drilled in the bottom plate 12, and the female die 14 may be used as the bottom plate 12 without providing the bottom plate 12. That is.
[0053]
  Thereafter, after holding at 1100 ° C. for 30 minutes, after slow cooling, performing deburring and predetermined cutting, an annealing process is performed, and the molded product shown in FIGS. 3B and 3D is completed. To do.
[0054]
  On the other hand, the next molding frame 7 is placed on the work table 3a after moving to the furnace preliminary chamber, and molding is performed in the same procedure as described above.
[0055]
  As described above in detail, in the present embodiment, the male mold 13 and the female mold 14 that are always in contact with the quartz glass block 15 at the time of pressure molding are formed by using a material in which the graphite material itself has air permeability. CO, CO produced by reaction of quartz glass and graphite₂, SiC and other gases can be easily released out of the molding space.
  CO, CO₂The ability to easily release gases such as SiC to the outside of the molding space prevents the formation of silicon carbide on the glass surface, and further cracks occur after cooling due to the difference in thermal expansion, resulting in poor yield. In addition to eliminating the drawbacks of the glass mold, the slippage between the mold and the glass due to the adhesion of silicon carbide is deteriorated, and the disadvantage that the glass does not enter the details of the mold can be solved.
[0056]
  That is, according to the present embodiment, after the male mold comes into contact with the support body by the raising and lowering means, the fluid pressure urging means urges the quartz glass lump through the male mold while energizing the quartz glass block. By performing pressure molding under heating, accurate molding can be performed.
  In this case, it is preferable to use an incompressible hydraulic cylinder as the fluid pressure urging means. In particular, by forming the hydraulic cylinder via the pressure detecting means, the applied pressure can be accurately maintained.
[0057]
  The pressure applied to the quartz glass block by the fluid pressure urging means through the male die is preloaded by the weight of the male die before the quartz glass block begins to deform, and at a predetermined pressure near the melting temperature. By giving, since it shape | molds gradually according to the degree of heat softening, a shaping | molding process can be performed accurately and without bubble entrainment, and it is preferable.
[0058]
  In addition, the present embodiment has a structure in which the upper male mold is in contact with the support and the quartz glass block is pressed by raising the work table disposed on the lower side, and the female mold is directly softened quartz. Since the glass lump is configured to be pushed out to the outer peripheral portion of the female mold, accurate molding is possible.
  Further, since the male mold on the upper surface side of the molding frame is in contact with the support, it is only necessary to open the lower side in the furnace where the work table is raised and lowered without opening the upper surface side in the furnace.
  As a result, in the configuration in which the upper part in the conventional furnace is opened, the furnace temperature decreases to near room temperature each time the furnace is opened, and the temperature rise time in the next molding process becomes extremely large. Since the atmosphere can be left in the furnace, it is extremely advantageous as an apparatus for performing continuous molding.
[0059]
  In this case, in order to facilitate continuous molding, an opening is provided below the furnace space in which the heating element is enclosed, two shutters are provided in the opening, and the two shutters face the furnace space. The upper shutter 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 alternately laminated with, for example, a quartz glass plate, thereby providing heat resistance and heat insulation in the former. The latter can maintain sealing performance and strength.
[0060]
  Further, the glass body is heated by induction heating means so that the temperature can be quickly raised to the heating region, 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 rate of temperature rise is too fast, the temperature difference between the peripheral area and the center of the glass body becomes large, and accurate molding cannot be performed.
  Therefore, in the present embodiment, the heating rate of the glass body after heat softening is set to 35 to 55 ° C./min, preferably 40 to 50 ° C./min.
[0061]
  Note that the moving speed of the elevating means is such that the shape of the female mold is complex and can be accurately molded without buckling, and the molding time is not unnecessarily delayed. The moving speed of the elevating means may be set at a slow speed of 2 to 10 mm / min, preferably 3 to 5 mm / min.
  In this case, a detecting means for detecting the movement amount of the fluid pressure urging means is provided, and the furnace temperature reaches a temperature range of about 1700 to 2000 ° C., and the detecting means detects the deformation completion position of the quartz glass block. After that, it is better to hold the molding completion position for a predetermined time, specifically 3 to 15 minutes, preferably 5 to 10 minutes, and wait for the deformation of the quartz glass block to be completed. Immediately through the fluid pressure biasing means, the female mold is lowered in the return direction to release the pressure, thereby preventing the reaction between the molding frame and the fused silica glass and preventing the protrusion during molding.
  Note that a hydraulic cylinder is used as the fluid pressure urging means in order to hold the deformation completion position with high accuracy and to enable accurate elevation control.
  Further, in this embodiment, the pressure molding is performed from the lower part, but it goes without saying that the pressure molding may be performed from the upper part.
[0062]
【Example】
(1) Using the molding method described above, a quartz glass container A as shown in FIG. 4A was manufactured under the following conditions.
  Quartz glass block: φ240 × 70 mm (total surface area (M): 1432 cm²)
  Female caliber (D): φ320mm
  Female recess depth (H): 200 mm
  Ratio (D / H): 370/200 = 1.85
  Maximum molding temperature: 1940 ° C
  Molding load: 20-80kgf
  Molding time: 120min
  Molded product size: D = φ370 mm, H = 200 mm, G = 25 mm,
                T = 5mm, E = 135mm, V = 60mm
  Total surface area of molded product (N): 3870cm²
  Area ratio (N / M): 3870/1432 = 2.70
[0063]
(2) Using the molding method described above, a quartz glass container B as shown in FIG. 4B was manufactured under the following conditions.
  Quartz glass block: φ140 × 47mm (total surface area (M): 514 cm²)
  Female caliber (D): φ240mm
  Female recess depth (H): 130 mm
  Ratio (D / H): 240/130 = 1.85
  Maximum molding temperature: 1920 ° C
  Molding load: 20-80kgf
  Molding time: 90min
  Molded product size: D = φ240 mm, H = 130 mm, G = 10 mm,
                T = 10mm, E = 20mm, V = 100mm
  Total surface area (N) of molded product: 1426cm²
  Area ratio (N / M): 1426/514 = 2.77
[0064]
  From the above data, the projected area S (cm²) And thickness T (mm / cm²) Ratio T / S (mm / cm)²), T / S = 0.05 (mm / cm²) The above quartz glass block is placed between the male mold and the female mold, and melted under high temperature heating and press-formed to form an aperture D corresponding to the outer diameter of the female mold opening, It can be seen that a good quartz glass container can be manufactured by forming a mold so that the depth H of the recess has a relationship of D / H = 1.85 (that is, 2.0 to 1.3). .
[0065]
  Further, the total surface area M of the quartz glass block that is placed between the male mold and the female mold and is pressure-molded, and the quartz glass to be moldedcontainerA good quartz glass container can be manufactured by forming a mold so that the total surface area N of N / M is 2.77 (that is, 2.0) or more.
[0066]
【The invention's effect】
  As explained above,BookIn the invention, the ratio T / S between the projected area S and the thickness T between the male mold and the female mold is T / S = 0.05 (mm / cm²) Since the above quartz glass block (ingot, block, etc.) is placed, melted under high temperature heating, and pressure-molded, a plate having the necessary thickness by remelting or cutting the quartz glass block again The quartz glass lump need only be a lump having a necessary volume, and the quartz glass lump may be pressure-molded under high temperature heating, so that the manufacturing process can be reduced.
[0067]
  The present invention also provides a quartz glass formed by a male mold and a female mold at the time of pressure molding.containerThe aperture diameter D corresponding to the outer diameter of the opening on one side of the lens and the height H from the closed bottom on the other side to the front surface of the opening are D / H = 1.85 (that is, 2.0 to 1.. 3) mold to have the relationship
  The present invention also provides a total surface area M of a quartz glass lump that is placed between a male mold and a female mold and is pressure-molded, and a quartz glass that is molded.containerAnd forming a mold so that the total surface area N of N / M = 2.77 (ie, 2) or more
  Since the quartz glass block placed between the molds is gradually cooled from the molten state, a complicated shaped quartz glass container having a deep bottom can be easily formed.
[0068]
  In addition, the male mold and the female mold can press a quartz glass lump in a range of 5 to 100 (preferably 10 to 80, more preferably 20 to 40) Kgf in a molding space having a graphite frame on the periphery. And is set to be heated in the range of 1700 ° C. to 2000 ° C. (desirably 1800 ° C. to 2000 ° C., more preferably 1840 ° C. to 1960 ° C.). Since the quartz glass fluid can flow to the corner of the mold by pressing in the range of ˜100 Kgf, a quartz glass container having a complicated shape can be manufactured with high accuracy.
[0069]
  In the present invention, the pre-load on the quartz glass block by the male mold and the female mold is once maintained, and further pressure is applied according to the softening of the quartz glass block. The quartz glass fluid can be placed at the optimum position of the center part of the bottom of the female mold, and is initially held at a pre-load and gradually pressurized according to the degree of heat softening of the quartz glass mass. Flows from the central portion toward the peripheral portion, which is preferable because it can be molded accurately and without entrainment of bubbles.
[0070]
  Further, according to the present invention, when the quartz glass block reaches a temperature range of 1700 ° C. to 2000 ° C., the quartz glass block is switched from pressurization by the weight of the male and female dies to forced pressurization by hydraulic pressure. The pressure is applied to the quartz glass block, and after the deformation of the quartz glass block is completed, the pressure is further increased. As the contact area of the mold changes, the pressure is applied to follow it, and if the male mold does not displace even if pressurized, the quartz glass fluid is moved to the corners of both molds by further pressing and holding. Inflowing can be performed with higher accuracy.
[0071]
  In the present invention, the rate of temperature increase to the quartz glass block is 35 to 55 ° C./min (preferably 40 to 50 ° C./min), and the moving speed of the mold by the male mold or the female mold is 2 to 10 mm. / Min (preferably 3 to 5 mm / min), so that even if the shape of the mold is complex, the molding can be performed accurately and without buckling, and the molding time is not delayed unnecessarily. Can be possible.
[Brief description of the drawings]
FIG. 1 is a schematic view of a quartz glass lump thermoforming frame according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram for explaining the concept of a quartz glass block.
FIG. 3 is an explanatory diagram for explaining a molding state of a quartz glass container.
FIG. 4 is an explanatory diagram for explaining the shape of a molded quartz glass container.
FIG. 5 is a schematic view of a quartz glass lump heat molding apparatus according to an embodiment of the present invention.
6 is a detailed view of a quartz glass lump heat molding apparatus according to an embodiment of the present invention based on the basic configuration of FIG.
[Explanation of symbols]
  13 Male
  14 Female
  15 Quartz glass block

Claims (1)

The quartz glass body in the manufacturing method of the quartz glass container to produce a quartz glass vessel was pressure-molded under a high-temperature heating is sandwiched between the male and female,
The male and female are formed by using a porous graphite gas permeability has a 0.1 cm ² values of /sec(P:1.5Kgf/cm ²⁾ or more breathable,
The total surface area M of the quartz glass block that is placed between the male mold and the female mold and is pressure-molded and the total surface area N of the quartz glass container to be molded have a relationship that N / M = 2 or more. And
The projected area S (cm ² ) and the wall thickness T (mm) of the surface perpendicular to the pressing direction between the male mold and the female mold are T / S = 0.05 (mm / cm ² ) or more. The quartz glass container is molded with a quartz glass lump having the following relationship, and when the quartz glass lump reaches a temperature range of 1700 ° C. to 2000 ° C., the male and female dies are placed on the quartz glass lump. Switch from pressurization due to its own weight to forced pressurization,
The quartz glass container formed by the male mold and the female mold has a diameter D corresponding to the outer diameter of the opening on one side, and a height H from the closed bottom on the other side to the front of the opening. method for producing a quartz glass container, characterized in that to produce the quartz glass container having a relation of D / H = 2.6~0.7.

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