JP2007001812A - Method and apparatus for manufacturing quartz glass rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing a quartz glass rod having remarkably excellent dimensional precision of the outer diameter at high yield. <P>SOLUTION: The method of manufacturing the quartz glass rod is carried out by heating and softening a rod like quartz glass base material 11 successively from one side while rotating and moving along the axial direction while controlling the moving rate to control the outer diameter of the quartz glass rod. The apparatus for manufacturing the quartz glass rod comprises a chuck 15 for grasping the rod like quartz glass base material to be rotatable and moving in the axial direction, a heating means 17 for heating the rod like quartz glass base material, a forming and drawing die 20 for forming the heated and softened part of the rod like quartz glass base material into a prescribed shape by injecting into the die, and a chuck 16 for grasping the formed quartz glass rod to be rotatable and moving the quartz glass rod in the axial direction. The cross-sectional shape of the inner wall of the forming and drawing die comprising an inlet side opening part, a drawing part and a hole part is curved at the drawing part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for manufacturing a quartz glass rod with high dimensional accuracy and high yield.

  In recent years, with the progress of optical communication technology, the use of optical fibers has increased. The optical fiber is usually manufactured by drawing an optical fiber preform called an optical fiber preform.

  Common optical fiber preforms (base materials before drawing) are mainly VAD method (Vapor phase Axial Deposition Method), OVD method (Outside Vapor Phase Deposition Method), MCVD Manufactured by the method (Modified Chemical Vapor Deposition Method). Then, by drawing this optical fiber preform at a high speed, an optical fiber having a target outer diameter can be obtained.

  For example, in the case of the VAD method, a core glass rod through which light actually passes is used as a starting glass rod, and a composite of core rod / glass fine particles is synthesized by depositing glass particles on the outer periphery of the starting glass rod. After the glass body is sintered in a heating furnace to form a glass body, the glass body is subjected to a drawing process to form a fiber preform, and then the preform is drawn in a drawing furnace to produce an optical fiber. In this method, a quartz glass rod called a cylindrical dummy rod is welded and connected to both ends of a starting glass rod. The quartz glass rod is also used as a shaft for suspending the composite when synthesizing the core rod / glass fine particle composite. And the quartz glass rod used in this way is required to have very strict dimensional accuracy such as no difference in outer diameter from the starting glass rod and less bending because it is used in a rotated state. . On the other hand, from the viewpoint of reducing optical communication costs, it is required that the dummy rod, which is a consumable item, be inexpensive.

  Patent Document 1 discloses a method for producing a quartz glass rod. This method is a method in which a quartz glass ingot serving as a base material is softened in a heating furnace and is stretched in the vertical direction by a stretching drive roller installed in the lower part of the heating furnace. And it is going to manufacture the quartz glass stick | rod which raised the outer diameter precision by controlling the torque of an extending | stretching drive part to a fixed range.

  Patent Document 2 discloses another method for producing a quartz glass rod. In this method, both ends of the quartz glass ingot are held by a fixed chuck and a moving chuck, respectively, softened locally in a heating furnace, and then stretched by moving the position of the moving chuck. Here, the outer diameter of the quartz glass rod that is actually stretched is monitored, and the outer diameter is controlled by adjusting the moving speed of the moving side chuck.

  Furthermore, Patent Document 3 discloses a method of forming a quartz glass ingot by press-fitting a heated quartz glass material into a forming die while rotating it. Since the quartz glass material is passed through the heating device while being rotated, the quartz glass material can be heated uniformly in the radial direction, and deformation of the heated quartz glass material can be prevented.

JP-A-3-115131 JP-A-2-275723 JP 2000-67411 A

  In the case of the vertical stretching method described in Patent Document 1, the outer diameter of the quartz glass rod that is actually stretched is monitored, and the outer diameter is within a certain range in order to adjust the rotation speed of the stretching drive roller. However, the outer diameter fluctuates within that range. In addition, since the quartz glass ingot as a base material moves only in the vertical direction, it is necessary to match the central axes of the quartz glass ingot and the stretching drive roller with higher accuracy. Otherwise, since it is affected by the temperature distribution in the cross section of the heating furnace, a viscosity difference is generated in the cross section of the quartz glass ingot, and a bent or non-circular portion is generated in the quartz glass rod being drawn.

  In the case of the method described in Patent Document 2, the outer diameter of the quartz glass rod that is actually stretched is monitored, and the outer diameter is within a certain range in order to adjust the moving speed of the moving side chuck. However, the outer diameter fluctuates within that range. In addition, since the quartz glass ingot is rotated for the bent part and the non-circular part, it is possible to suppress the viscosity difference in the cross section of the quartz glass ingot. Although generation | occurrence | production can be suppressed, since adjustment of the moving speed of the movement side chuck | zipper with respect to ductility is very difficult, dripping arises during extending | stretching and bending may be generated as a result.

  Therefore, it is difficult to obtain a quartz glass rod having excellent dimensional accuracy with little fluctuation in outer diameter and little bending in any of the manufacturing methods. In addition, in order to control the outer diameter by monitoring the outer diameter at the start of stretching, the portion that has been stretched from the start of stretching until reaching the target outer diameter, Since it is not a quartz glass rod, the yield is reduced by this amount.

  Furthermore, since the method described in Patent Document 3 uniformly heats the quartz glass material in the radial direction, the quartz glass material can be prevented from being deformed. There is no mention of accuracy or yield.

  An object of the present invention is to solve such problems and to provide a method and a manufacturing apparatus for manufacturing a quartz glass rod with high dimensional accuracy and high yield.

  The method for producing a quartz glass rod according to the present invention is any of the following (1) to (4), and the apparatus for producing a quartz glass rod according to the present invention is the following (5). Hereinafter, these may be collectively referred to as the present invention.

  (1) A method for producing a quartz glass rod by rotating a rod-like quartz glass material while heating and softening sequentially from one end and moving it in the axial direction, and feeding the heated and softened portion into a forming and drawing die, A method for producing a quartz glass rod, wherein the outer diameter of the quartz glass rod is controlled by adjusting a feed rate of the material.

  (2) The method for producing a quartz glass rod according to (1), wherein the feeding speed of the quartz glass material is adjusted using the observation result of the molding state of the rod-like quartz glass material.

  (3) When the heat-softened portion of the rod-shaped quartz glass material is fed into the forming and drawing die, the outer diameter of the heat-softening portion is once increased at the opening on the inlet side of the forming and drawing die, and then the extending portion of the forming and drawing die is The method for producing a quartz glass rod according to the above (1) or (2), wherein the quartz glass rod is fed into the hole.

  (4) The quartz according to any one of (1) to (3) above, wherein the shape-drawing die is such that the cross-sectional shape in the axial direction of the inner wall of the shape-drawing die is a curve in the drawing portion of the shape-drawing die. A method of manufacturing a glass rod.

  (5) Gripping the rod-shaped quartz glass material in a rotatable state and moving it in the axial direction, heating means for heating the rod-shaped quartz glass material, and heat-softening part of the rod-shaped quartz glass material are press-fitted A quartz glass rod manufacturing apparatus having a molding drawing die for molding into a predetermined shape and a chuck for holding the molded quartz glass rod in a rotatable state and moving it in the axial direction. An apparatus for producing a quartz glass rod, characterized in that the cross-sectional shape in the axial direction of the inner wall of a forming and drawing die comprising a part, an extending part and a hole is a curve from the opening on the inlet side to the hole.

  According to the present invention, it is possible to manufacture a quartz glass rod having a very good outer diameter dimensional accuracy with a high yield.

  The method for producing a quartz glass rod according to the present invention is to heat and soften sequentially from one end while rotating a rod-like quartz glass material and move it along the axial direction, and press-fit the heat-softened part into a forming and drawing die. This adjusts the feeding speed of the quartz glass material.

  The present invention will be described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of an apparatus for producing a quartz glass rod used in the present invention.

  In this apparatus, first, a rod-shaped quartz glass material 11 is gripped by an entrance side chuck 15 and an exit side chuck 16 via an entrance side dummy material 13 and an exit side dummy material 14, respectively. As the dummy material, for example, a quartz glass rod or a pipe can be used, and this is attached to both ends of a rod-like quartz glass material by welding or the like. The rod-shaped quartz glass material 11 gripped by the inlet side chuck 15 and the outlet side chuck 16 is sent out in the direction of the forming and drawing die 20 while rotating (from left to right in FIG. 1).

  The ratio of the traveling speed of the entrance side chuck 15 and the traveling speed of the exit side chuck 16 is the ratio of the transverse area of the rod-shaped quartz glass material 11 and the transverse area of the quartz glass rod 12 after molding having a predetermined outer diameter. Set to the reciprocal. Here, it is preferable that the rotational speed of the entrance side chuck 15 and the rotational speed of the exit side chuck 16 are the same. This is because a twisted pattern is likely to occur on the outer surface of the quartz glass rod 12 after forming if a rotational speed difference is provided.

  A heater 17 is installed between the entrance side chuck 15 and the exit side chuck 16, and a part of the rod-like quartz glass material 11 is sequentially heated above the softening point by the heater 17 to become a heat-softening part, and a mold drawing die. 20 is sent. The inner diameters of the inlet-side opening 21 and the hole 23 of the forming and drawing die 20 are set in accordance with the outer diameter of the rod-shaped quartz glass material 11 to be used and the outer diameter of the target quartz glass rod 12.

  The heat-softened portion of the rod-shaped quartz glass material is molded and stretched by passing the molding and drawing die 20 to obtain a quartz glass rod 12 having a target outer diameter.

  FIG. 2 is a longitudinal sectional view showing a process in which the heat-softened portion of the rod-shaped quartz glass material 11 is formed and stretched in the present invention to manufacture the quartz glass rod 12.

  The heat-softened quartz glass material 11 is fed into the forming and drawing die 20 while rotating. The inner wall of the forming and extending die 20 includes an inlet opening 21, an extending portion 22, and a hole 23. The heat-softened quartz glass material 11 that has been sent hits the opening 21 on the inlet side of the forming and drawing die 20, and once formed here, it is drawn in the drawing portion 22, and then pulled out from the outlet of the hole portion 23. A quartz glass rod 12 having a desired outer diameter is formed.

  At this time, once the drawing speed is set to a predetermined value, there is no need for adjustment thereafter. That is, the drawing speed of the quartz glass rod 12 formed by drawing is the outer diameter when the heat-softened quartz glass material 11 fed into the forming and drawing die hits the inlet-side opening 21 of the forming and drawing die 20. Is determined by adjusting. The outer diameter of the quartz glass material 11 that has been softened by heating can be adjusted by adjusting the feeding speed of the quartz glass material 11 when the quartz glass material 11 is molded by hitting the inlet-side opening 21 of the forming and drawing die 20.

  The method for adjusting the feeding speed of the rod-shaped quartz glass material 11 is not particularly limited, but it is preferable to use the observation result of the molding state such as the outer diameter of the rod-shaped quartz glass material 11. The molding state such as the outer diameter of the quartz glass material 11 may be observed using, for example, a CCD camera.

  Thus, by adjusting the feeding speed without adjusting the drawing speed, that is, by controlling the supply side of the quartz glass material in the forming and drawing die, the quartz glass rod 12 having the target outer diameter is made uniform and continuous. The quartz glass rod 12 with excellent outer diameter accuracy can be manufactured. Further, in the case of the present invention, since it is molded and stretched to the quartz glass rod 12 having a desired outer diameter through the molding and stretching die 20, the entire area from the front end to the rear end of the quartz glass material 11 can be used without waste. Therefore, the yield can be greatly improved as compared with the conventional method.

  Note that the outer diameter of the heat-softened quartz glass material 11 that is fed into the inlet-side opening 21 of the forming and drawing die 20 is formed from the outer diameter of the rod-shaped quartz glass material 11 as shown in FIG. If it is a little larger, it can be confirmed that the heat-softened quartz glass material 11 is sufficiently supplied along the inner wall of the forming and drawing die 20, so whether or not the drawing portion 22 is sufficiently drawn indirectly. Can be confirmed.

  Therefore, it is preferable to increase the outer diameter of the heat-softened portion at the inlet-side opening 21 of the forming and drawing die 20 and then feed it into the hole 23 through the extending portion 22. It is preferable to make the diameter about 10 to 20 mm larger than the outer diameter of the rod-shaped quartz glass material.

  The quartz glass material constituting the rod-shaped quartz glass material is not limited to synthetic quartz glass manufactured by the VAD method or the like, and other quartz glass such as natural quartz glass made from quartz powder or the like can be used. it can.

  Since the softening point of the heat-softening temperature of the rod-shaped quartz glass material varies greatly depending on the OH group concentration, Cl concentration, etc. of the quartz glass material, the heater may be set to an appropriate temperature condition accordingly. Although it is difficult to measure the temperature of the quartz glass material during forming and stretching, the set temperature of the heater is about 2000 to 2500 ° C.

  Moreover, it is preferable that the temperature of the heat-softened quartz glass material fed into the forming and drawing die is slightly lower than the maximum temperature of the quartz glass material heated by the heater. In other words, the temperature of the quartz glass material gradually increases from the chuck side by the heater, reaches the highest temperature immediately before being fed into the forming and drawing die, and contacts the forming and drawing die when the temperature drops slightly. It is preferred that Thus, if the temperature of the quartz glass material is once increased and then formed and stretched at a temperature slightly lower than that, further deformation of the quartz glass rod can be prevented. At this time, it becomes possible to manufacture a quartz glass rod particularly excellent in terms of dimensional accuracy.

When the set temperature of the heater is about 2000 to 2500 ° C. as described above, materials that can be applied to jigs and tools such as forming and drawing dies are limited. Specifically, Al ₂ O ₃ , MgO, ZrO ₂ -based oxides, graphite, W, Mo and the like can be used. Among them, graphite is the most in view of strength and purity in a high temperature range. preferable. In addition, since the forming and drawing die is in direct contact with the quartz glass material, when there is a concern about impurity contamination of the manufactured quartz glass rod, it is preferable to use a purified graphite material with few impurities. In addition, the stretching is preferably performed in an inert atmosphere to prevent oxidation.

  Next, the preferable shape of the shaping | molding extending | stretching die used for this invention is demonstrated based on the Example of FIG.

  FIG. 3 shows an axial sectional view of the inner wall of the forming and drawing die.

  The forming and extending die 20 includes an inlet opening 21, an extending portion 22, and a hole portion 23. As shown in FIG. 3, the heat-softened quartz glass material 11 that has been fed hits the inlet-side opening 21 of the molding and drawing die 20 as described above, and once formed here, it is stretched at the stretching portion 22. Thereafter, the quartz glass rod 12 having the desired outer diameter is formed by being pulled out from the outlet of the hole 23. Thus, in the extending | stretching part 22, the heat-softened quartz glass raw material 11 receives a deformation process.

  Therefore, it is preferable that the quartz glass material 11 heated and softened along the inner wall surface moves without breaking at this time, and for this purpose, the axial cross-sectional shape of the inner wall of the forming and drawing die 20 is set at the extending portion 22. A curve is preferred.

  The inner diameter A of the inlet opening 21 of the forming and drawing die 20 needs to be larger than the outer diameter of the rod-shaped quartz glass material 11, and the inner diameter B of the hole is the outer diameter of the target quartz glass rod 12. It is necessary to match with the dimensions.

  As described above, adjustment of the outer diameter when the heat-softened quartz glass material 11 strikes the inlet-side opening 21 of the forming and drawing die 20 is possible by adjusting the feeding speed of the quartz glass material 11. In order to ensure an appropriate adjustment range, the inner diameter A of the inlet opening 21 is desirably about 30 to 50 mm larger than the outer diameter of the rod-shaped quartz glass material 11.

  Further, the length C of the hole 23 of the forming and drawing die 20 is set to an appropriate length according to the temperature at which the heat-softened quartz glass material 11 is in contact with the forming and drawing die 20, the drawing speed of the target quartz glass rod, and the like. do it. However, if the length C of the hole 23 is too short and the extending portion 22 is extremely close to the outlet of the heater 17, the temperature of the heat-softened quartz glass material 11 may be lowered below the softening point. In such a case, the quartz glass rod 12 may be broken in the forming and drawing die 20. Conversely, if the length C of the hole is too long, the stretched portion 22 and the front half of the hole 23 come closer to the center of the heater 17 and the viscosity of the quartz glass material decreases, so that the deformation further proceeds after forming and stretching. Therefore, the target outer diameter may not be ensured.

  Furthermore, as shown in FIG. 3, it is preferable to provide, for example, an inert gas introduction hole 30 such as nitrogen gas on the inner surface of the forming and drawing die 20, and the quartz glass rod 12 is introduced by introducing the inert gas. It is possible to enhance the cooling effect immediately before and / or immediately after the film is stretched. Thereby, the further deformation | transformation after shaping | molding extending | stretching can be prevented. As for the inert gas introduction hole for cooling, the hole diameter, the number, the position and the like are not particularly limited, and may be set appropriately depending on the processing temperature, the drawing speed and the like. In addition, when installing the inert gas introduction hole for cooling, it is preferable to install so that each surface may be cooled equally.

  Next, the example of the curve of the inner wall of the shaping | molding extending | stretching die | dye used for this invention is demonstrated.

  FIG. 4 is an axial sectional view showing an example of the inner wall of the forming and drawing die used in the present invention. The curve of the inner wall of the forming and drawing die (a) is obtained by rounding a corner formed by a straight line that forms the inlet opening and a straight line that forms the hole. The curve of the inner wall of the forming and drawing die (b) is formed by forming three straight lines between the inlet opening and the hole, and rounding each corner. The number of straight lines that form between the inlet opening and the hole is not limited to three, but may be four or more, but at least the corner that forms the extension is rounded off. The curve of the inner wall of the forming and drawing die (c) is formed by combining elliptical arcs. The curve of the inner wall of the forming and drawing die (d) is formed by a combination of an arc and an elliptical arc. In any case of (a) to (d), the length of the straight line constituting each curve, the length of the arc and the elliptical arc depends on the outer diameter of the quartz glass material and the outer diameter of the manufactured quartz glass rod. Just design. Moreover, although the magnitude | size of a rounded corner is based also on the outer diameter of the manufactured quartz glass rod, it is about 2 to 20 times the radius of the manufactured quartz glass rod, and about 8 to 12 times is preferable.

  As shown in FIG. 4, the curved shape of the inner wall of the formed drawing die can be variously varied. However, if the curve is too complicated, the manufacturing cost becomes high. Therefore, it is preferable to round the corner portion formed by the straight line forming the inlet opening and the straight line forming the hole shown in FIG.

(Example of the present invention)
A high-purity quartz powder (silica powder) was deposited in the vertical direction while melting in an oxyhydrogen flame to produce a natural quartz glass ingot. And the outer periphery was ground and the rod-shaped quartz glass raw material was obtained.

  From this quartz glass material (outer diameter 140 mm, length 750 mm), a quartz glass rod was manufactured by using the manufacturing apparatus of FIG. 1 and targeting an outer diameter of 50.15 mm according to the method of the present invention. The set temperature of the heater is 2300 ° C., the rotation speed is 10 rpm, the feeding speed of the rod-shaped quartz glass material is set to 14.76 mm / min, the drawing speed of the generated quartz glass rod is set to 115.06 mm / min, went. In addition, the thing of FIG. 3 was used for the forming and drawing die. The inner diameter A of the inlet opening of the forming and drawing die was 170 mm, the inner diameter B of the hole was 50.15 mm, and the length C of the hole 23 was 120 mm. Moreover, the curve of the extending part was obtained by rounding a corner part formed by the straight line forming the inlet opening and the straight line forming the hole shown in FIG.

  The outer diameter of the quartz glass rod being produced was monitored from the beginning to the end of molding, but the drawing speed was not adjusted at all, and the heating softening part of the quartz glass material was molded from the feed side of the rod-shaped quartz glass material. While observing the state, the feeding speed of the rod-shaped quartz glass material was finely adjusted between 14.30 and 15.00 mm / min.

  In FIG. 5, the fluctuation | variation state of the outer diameter of the quartz glass rod manufactured in the example of this invention is shown. As a result, the average outer diameter was 50.15 mm, the maximum outer diameter was 50.21 mm, the minimum outer diameter was 50.06 mm, and the standard deviation was 0.02 mm. Thus, only by finely adjusting the feeding speed of the rod-shaped quartz glass material, a quartz glass rod having a target outer diameter was stably obtained from the start to the end of stretching.

  Next, in order to measure the bending of the manufactured quartz glass rod, the manufactured quartz glass rod is cut into 1000 mm, both ends are fixed with V blocks, and the displacement of the central portion of the quartz glass rod is measured with a dial gauge. When calculated by the following equation (1), the bending was 0.04 mm.

Bend (mm) = (Displacement at the center of quartz glass rod) / 2
In the above description, when the normal outer diameter tolerance is ± 0.5 mm, the yield of the non-defective part with respect to the total stretched length was 100%.

(Comparative example)
With respect to the method for producing a quartz glass rod according to the present invention example, a quartz glass rod was processed according to the vertical centrifugal method described in Patent Document 1 with an outer diameter of 50.15 mm as a target.

  As for the quartz glass material, a natural quartz glass ingot was prepared by depositing high-purity quartz powder (silica powder) in the vertical direction while melting with an oxyhydrogen flame, as in the present invention example. And the rod-shaped quartz glass raw material (outer diameter 140mm, length 750mm) obtained by grinding the outer periphery was used.

  The heating temperature is set to 2300 ° C., the feeding speed of the rod-shaped quartz glass material is set to 14.76 mm / min, and the drawing speed of the generated quartz glass bar is set to 115.06 mm / min (the stretching drive roller speed is 0.30 rpm), Stretching was performed. In order to approach the target outer diameter while monitoring the outer diameter of the generated quartz glass rod from the start to the end of stretching, the pulling speed of the quartz glass rod is 95 to 140 mm / min (0 at the rotation speed of the stretching drive roller). .25 to 0.37 rpm).

  In FIG. 6, the fluctuation | variation state of the outer diameter of the quartz glass rod manufactured in the comparative example is shown. As a result, the average outer diameter was 50.71 mm, the maximum outer diameter was 58.19 mm, the minimum outer diameter was 49/53 mm, and the standard deviation was 1.08 mm. In this way, the drawing speed was adjusted while monitoring the outer diameter of the quartz glass, but not only did it take a considerable amount of time to reach the target outer diameter, but the outer diameter constantly increased after approaching the target outer diameter. It fluctuated.

  Next, in order to measure the bending of the drawn quartz glass rod, the drawn quartz glass rod is cut into 1000 mm, both ends are fixed with V blocks, and the displacement amount at the center of the quartz glass rod is measured with a dial gauge. The bending was 0.38 mm as calculated by the following formula (1).

Bend (mm) = (Displacement at the center of quartz glass rod) / 2
In the above, when the normal outer diameter tolerance is ± 0.5 mm, the yield of the non-defective part with respect to the total stretched length was 68%.

  FIG. 6 shows, on the same scale, both fluctuations in the outer diameter of the quartz glass rods produced in the present invention example and the comparative example. According to the example of the present invention, it has been confirmed that a quartz glass rod with extremely good outer diameter dimensional accuracy can be manufactured with high yield.

  According to the present invention, it is possible to manufacture a quartz glass rod having a very good outer diameter dimensional accuracy with a high yield.

It is a longitudinal cross-sectional view of the manufacturing apparatus of the quartz glass rod which concerns on this invention. It is a longitudinal cross-sectional view which shows the process in which a quartz glass raw material is shape | molded and extended | stretched in this invention, and a quartz glass rod is manufactured. It is an axial sectional view showing the inner wall of the forming and drawing die used in the present invention. It is an axial direction sectional view showing an example of an inner wall of a forming extension die used for the present invention. The fluctuation | variation state of the outer diameter of the quartz glass rod manufactured in the example of this invention is shown. The fluctuation | variation state of the outer diameter of the quartz glass rod manufactured in the comparative example is shown. Both the fluctuation | variation conditions of the outer diameter of the quartz glass rod manufactured in this invention example and the comparative example are shown by the same scale.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Quartz glass raw material 12 Quartz glass rod 13 Inlet side dummy material 14 Outlet side dummy material 15 Inlet side chuck 16 Outlet side chuck 17 Heater 20 Molding extending | stretching die 21 Inlet opening part 22 Extending part 23 Hole part 30 Inert gas introduction hole A Inner diameter of inlet opening B Inner diameter of hole C Length of hole

Claims (5)

  A method for producing a quartz glass rod by rotating a rod-like quartz glass material from one end while rotating and softening the rod-shaped quartz glass material in the axial direction, and feeding the heated and softened portion to a forming and drawing die. A method for producing a quartz glass rod, wherein the outer diameter of the quartz glass rod is controlled by adjusting the speed.   The method for producing a quartz glass rod according to claim 1, wherein the feeding speed of the quartz glass material is adjusted using an observation result of a molding state of the rod-like quartz glass material.   When the heat-softened portion of the rod-shaped quartz glass material is fed into the forming and drawing die, the outer diameter of the heat-softening portion is once increased at the inlet side opening of the forming and drawing die, and then the hole is passed through the extending portion of the forming and drawing die. The method for producing a quartz glass rod according to claim 1, wherein the quartz glass rod is fed to the quartz glass rod.   The quartz glass rod according to any one of claims 1 to 3, wherein a shape-drawing die having a cross-sectional shape in an axial direction of an inner wall of the shape-drawing die is a curve at a drawing portion of the shape-drawing die. Production method. A chuck for holding the rod-shaped quartz glass material in a rotatable state and moving it in the axial direction, a heating means for heating the rod-shaped quartz glass material, and a heating softening portion of the rod-shaped quartz glass material are press-fitted into a predetermined A quartz glass rod manufacturing apparatus having a forming and drawing die for forming into a shape and a chuck that holds the formed quartz glass rod in a rotatable state and moves it in the axial direction. An apparatus for producing a quartz glass rod, wherein an axial cross-sectional shape of an inner wall of a forming and drawing die comprising a portion and a hole is a curve in the extending portion.

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