Method for manufacturing a melt molding apparatus and a vibrator

Abstract

To provide a melt molding apparatus for manufacturing an oscillator.SOLUTION: A melt molding apparatus includes: a melt molding die including a hole having a flat upper surface, a shape cylindrically hollowed around a first axis perpendicular to the upper surface and a hole bottom surface and a pillar extending upward from the hole bottom surface around the first axis; and a burner having a second axis having the same axis as the first axis, arranged above the melt molding die and capable of generating a flame toward the hole from the tip part. The tip part includes a first opening constituted so as to eject fuel gas and arranged in rotational symmetry around the second axis, and when viewed from the second axis direction, the first opening surrounds the pillar and the first opening does not overlap the pillar.SELECTED DRAWING: Figure 1

Description

Technical Field

[0004]

[0001] This specification relates to a melt molding apparatus for a vibrator and a manufacturing method thereof.

Background Art

[0002] Patent Document 1 discloses a Bird-bath Resonator Gyroscope (BRG) that uses fused silica as a vibrator as a gyroscope capable of achieving high precision. A specific manufacturing method will be described. Prepare a melt molding die in which a hole is formed in a part of the upper surface. The hole is formed in a part of the upper surface around a central axis perpendicular to the upper surface of the molding die. Place a workpiece (e.g., a quartz plate) so as to close the hole, reduce the pressure on the lower surface of the workpiece, and heat the upper surface of the workpiece with a burner. By melting and deforming the workpiece so as to enter the inside of the hole, a hemispherical vibrator can be produced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] According to the above configuration, the center of the flame can be positioned rotationally symmetrically around the support column. This allows for two directions of heat conduction: one from the flame center towards the inner circumference (support column) and another from the flame center towards the outer circumference. As a result, the temperature difference between the support column and the edge of the hole can be reduced. This reduces the localized difference in the deformability of the workpiece, making it possible to manufacture an oscillator with good shape symmetry. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view of the melt molding apparatus 1 of Example 1. [Figure 2] This is a top view of the melt molding apparatus 1 of Example 1. [Figure 3] This diagram shows the configuration of Burner 50. [Figure 4] This is a flowchart illustrating the manufacturing process of oscillators. [Figure 5] This is a cross-sectional side view of a conventional melt molding apparatus 1001. [Figure 6] This is a cross-sectional side view of the melting molding apparatus 1. [Figure 7] This figure shows a modified example of the outer peripheral opening OT1. [Figure 8] This is a plan view of the burner tip 250s of Example 2. [Figure 9]This figure shows the burner tip 250s in a modified example of Example 2. [Figure 10] This is a plan view of the burner tip 350s of Example 3. [Figure 11] This is a cross-sectional side view of the melt molding apparatus 401 of Example 4. [Modes for carrying out the invention] [Examples]

[0008] (Configuration of the melt molding apparatus 1) Figure 1 shows a schematic cross-sectional view of the melt molding apparatus 1. Figure 2 shows a top view of the melt molding apparatus 1. Figure 1 corresponds to the cross-sectional view along line II in Figure 2. Note that in Figure 2, the burner 50, radiation thermometer 60, movable mechanism 53, and stage 45 are omitted from the description.

[0009] The stage 45 is configured to be movable in the x and y directions (horizontal direction). The stage 45 has a flat mounting surface 45s. The mold 20 is mounted on the mounting surface 45s via a heat sink 40 and a plate 10.

[0010] The heat sink 40 is positioned between the stage 45 and the mold 20. The heat sink 40 is in contact with the lower surface 10r of the plate 10. A circulation pipe 41 is located inside the heat sink 40. The circulation pipe 41 is connected to a chiller system 42. A heat transfer medium, kept at a constant temperature (e.g., 35°C) by the chiller system 42, circulates through the circulation pipe 41. This allows the heat sink 40 to maintain a constant temperature throughout the process.

[0011] The plate 10 is placed on the heat sink 40. The plate 10 is a stainless steel stand for mounting the mold 20. The plate 10 has the function of cooling the mold 20. A first connecting hole 10c1 is formed on the surface 10s of the plate 10. The first connecting hole 10c1 is positioned corresponding to the through hole 20e and is connected to the through hole 20e. The first connecting hole 10c1 is connected to a negative pressure generating means 81 via a first connecting passage 10p1. The negative pressure generating means 81 is a means capable of generating negative pressure in the hole 20h. The negative pressure generating means 81 may be, for example, a vacuum pump.

[0012] The mold 20 is placed on the surface 10s of the plate 10. The mold 20 is a mold for forming a hemispherical vibrator by melting and deforming the quartz plate 30. The material of the mold 20 is graphite. In this embodiment, the mold 20 is cylindrical with a central axis CA. The mold 20 comprises a lower surface 20r, an upper surface 20s, a hole 20h, a support column 20p, and a through hole 20e. The lower surface 20r and the upper surface 20s are flat surfaces perpendicular to the central axis CA. A hole 20h is formed in a part of the upper surface 20s. The hole 20h is a deformation space for the quartz plate 30 to melt and deform. In this embodiment, the hole 20h has a cylindrical shape hollowed out with the central axis CA as the center. The hole 20h has a bottom surface 20b. A support column 20p is positioned in the center of the hole 20h, extending vertically upward from the bottom surface 20b. The support column 20p is a cylinder with central axis CA as its central axis. The bottom surface 20b has multiple through holes 20e that penetrate through to the bottom surface 20r. The through holes 20e are in communication with the first connecting hole 10c1.

[0013] A quartz plate 30 is positioned on the upper surface 20s of the mold 20 so as to cover the hole 20h. The quartz plate 30 is the material to be processed for forming the oscillator. The quartz plate 30 is made of fused silica. The thickness of the quartz plate 30 is, for example, 100 μm. In this embodiment, the quartz plate 30 is square, but it may also be circular or a regular hexagon.

[0014] The upper end surface of the support column 20p is located at a position lower than the upper surface 20s of the mold 20. Thereby, a gap GA1 is formed between the lower surface of the quartz plate 30 and the upper end surface of the support column 20p. The gap GA1 may be an arbitrary value, for example, 100 to 500 μm. By forming the gap GA1, a heat conduction path to the support column 20p is not formed in the heating process (step S50) described later. Thereby, the heat damage given to the support column 20p can be suppressed. Also, in step S100 described later, when cutting unnecessary flat portions by CMP or the like, the support column 20p can be prevented from being removed.

[0015] The burner 50 is disposed above the central axis CA. The burner 50 includes a premixing chamber 50c, a tube 50t, and a burner tip 50s. The fuel gas G1 (e.g., propane) and the oxygen gas G2 are supplied from the gas flow regulator 52 to the premixing chamber 50c. The gas flow regulator 52 includes a mass flow controller (not shown) and can control and monitor the flow rates of the fuel gas G1 and the oxygen gas G2. The tube 50t extends downward from the premixing chamber 50c. The tube 50t is a cylindrical member having a burner central axis BA extending in the vertical direction. A burner tip 50s facing the hole 20h is disposed at the lower end of the tube 50t. By generating a flame from the burner tip 50s toward the hole 20h, the quartz plate 30 can be heated.

[0016] The burner 50 is fixed to the movable mechanism 53. The movable mechanism 53 is a mechanism movable in the vertical direction (±z direction). The movable mechanism 53 can move the burner tip 50s up and down along the central axis CA.

[0017] By applying the focus of the radiation thermometer 60 to the support column 20p, the radiation thermometer 60 can measure the temperature of the support column 20p non-contact. The temperature of the support column 20p indicates a temperature corresponding to the temperature of the quartz plate 30 during processing. Since it is very difficult to align the focus, which is the measurement point of the radiation thermometer 60, with the transparent quartz plate 30, it is possible to indirectly measure the temperature of the quartz plate 3 by measuring the temperature of the support column 20p.

[0018] The control unit 70 is connected to the stage 45, the movable mechanism 53, the gas flow regulator 52, the radiation thermometer 60, and the negative pressure generating means 81. The control unit 70 acquires various information from these devices and controls these devices. The control unit 70 may be, for example, a PC.

[0019] (Configuration of Burner 50) Fig. 3(A) shows a plan view of the burner tip 50s. Fig. 3(B) shows a cross-sectional view taken along line B-B of Fig. 3(A). An outer peripheral opening OT1 configured to eject fuel gas is arranged at the burner tip 50s. The outer peripheral opening OT1 has an annular shape centered on the burner central axis BA. That is, the outer peripheral opening OT1 is arranged rotationally symmetrically about the burner central axis BA.

[0020] As shown in Fig. 3(B), the upper part of the outer peripheral opening OT1 is connected to the pipe GP. The upper part of the pipe GP is connected to the premixing chamber 50c. Thereby, the mixed gas generated in the premixing chamber 50c can be ejected from the outer peripheral opening OT1 through the pipe GP.

[0021] Also, Fig. 2 shows the position of the outer peripheral opening OT1 when viewed from the direction of the burner central axis BA (+z direction) by a dashed-dotted line. The outer peripheral opening OT1 is located near the outer periphery of the hole 20h. The outer peripheral opening OT1 and the outer periphery of the hole 20h form concentric circles centered on the central axis CA. The diameter of the outer peripheral opening OT1 may be smaller than, larger than, or equal to the diameter of the hole 20h. In this embodiment, the case where the diameter of the outer peripheral opening OT1 is larger than the diameter of the hole 20h is described. The outer peripheral opening OT1 surrounds the support column 20p and the hole 20h. Also, the outer peripheral opening OT1 does not overlap with the support column 20p and the hole 20h.

[0022] (Manufacturing Process of the Vibrator) The manufacturing process of the oscillator will be explained using the flowchart in Figure 4. In step S10, the heat sink 40 is kept at a constant temperature by continuously circulating the heat transfer medium from the chiller equipment 42 to the circulation piping 41. A molding die 20 is also placed on the surface 10s of the plate 10.

[0023] In step S20, the quartz plate 30 is placed on the upper surface 20s of the mold 20. At this time, it is positioned so that the center axis CA and the center of the quartz plate 30 coincide. Based on a signal from the control unit 70, the negative pressure generating means 81 performs vacuuming of the first connecting hole 10c1. As a result, the hole portion 20h is also vacuumed through the through hole 20e, and the quartz plate 30 is adsorbed and fixed to the upper surface 20s of the mold 20. This results in the state shown in Figures 1 and 2.

[0024] In step S30, the control unit 70 starts measuring the temperature of the support column 20p using the radiation thermometer 60. In step S40, the control unit 70 ignites the burner 50. Ignition is performed in a retracted position where the burner tip 50s is sufficiently far from the surface of the quartz plate 30.

[0025] In step S50, the control unit 70 lowers the burner 50 by controlling the movable mechanism 53, thereby reducing the distance between the burner tip 50s and the quartz plate 30. This initiates the heating process of the quartz plate 30 by the flame.

[0026] The timing of when the descent begins, and the distance between the burner tip 50s and the quartz plate 30, can be controlled in various ways. For example, the descent may begin after a predetermined time has elapsed since the burner 50 was ignited in step S40, and stop when the burner tip 50s and the quartz plate 30 approach a predetermined distance. Alternatively, for example, the temperature of the support column 20p may be measured with a radiation thermometer 60, and the descent timing and the distance between the burner tip 50s and the quartz plate 30 may be determined by temperature feedback control.

[0027] A distributed load is applied to the quartz plate 30 due to the pressure difference between atmospheric pressure and the negative pressure inside the hole 20h. Therefore, as the quartz plate 30 is heated to its softening temperature (approximately 1600°C), it can be melted and deformed so that it fits into the hole 20h. If it is determined in step S60 that the melting and deformation of the quartz plate 30 is complete (S60:YES), the process proceeds to step S70. There are various methods for detecting the end of the processing. For example, it may be detected when the temperature of the support column 20p has risen to a temperature indicating the end of the processing. Alternatively, for example, it may be detected when a predetermined time has elapsed.

[0028] In step S70, the control unit 70 controls the movable mechanism 53 to raise the burner 50. In step S80, the control unit 70 stops the burning of the burner 50 by controlling the movable mechanism 53 and extinguishes the flame.

[0029] In step S90, the control unit 70 waits for the cooling to be completed. Once cooling is complete, the control unit 70 stops the negative pressure generating means 81. This opens the hole 20h to the atmosphere. In step S100, the molten quartz plate 30 is removed from the mold 20. The oscillator is completed by removing the unformed area on the outer circumference of the quartz plate 30 using methods such as CMP or laser cutting.

[0030] (assignment) The problem will be explained using a conventional melt molding apparatus 1001. Figure 5 shows a cross-sectional side view of the melt molding apparatus 1001. Figure 5(A) shows the state in which the flame FL0 is applied to the quartz plate 30. In Figure 5(A), the flame FL0 is shown as a dotted line. The heat input profile IP0 is shown as a solid line. The heat input profile IP0 shows the two-dimensional distribution of the amount of heat input to the quartz plate 30 by the flame FL0. The higher the heat input profile IP0 is located on the plane of the paper, the greater the amount of heat input. Figure 5(B) shows the two-dimensional temperature distribution TP0 of the quartz plate 30. The higher the temperature distribution TP0 is located on the plane of the paper, the higher the temperature. The heat input profile IP0 and temperature distribution TP0 can be measured, for example, by an infrared camera. In the conventional melt molding apparatus 1001, the center FC0 of the flame FL0 is located at the center of the hole 20h (support column 20p). Therefore, at support column 20p, the heat input has a peak PP0.

[0031] A heat conduction path is formed in the mold 20 to dissipate the heat input to the quartz plate 30. Specifically, a heat conduction path HP1 is formed in the contact area between the outer circumference of the hole 20h and the lower surface of the quartz plate 30. On the other hand, no heat conduction path is formed in the support column 20p. This is because a gap GA1 is formed between the upper surface of the support column 20p and the lower surface of the quartz plate 30, and they are not in contact. Therefore, until the center of the quartz plate 30 deforms and comes into contact with the support column 20p, the direction of heat conduction is unidirectional, from the center FC0 (support column 20p) toward the outer circumference (see arrow Y0). Consequently, the temperature distribution TP0 of the quartz plate 30 is highest at the center, the support column 20p, and decreases as you move away from the support column 20p toward the outer circumference (see Figure 5(B)). As a result, the temperature difference TD0 between the support column 20p and the edge 20m of the hole 20h was large.

[0032] The viscosity (ease of deformation) of the quartz plate 30 above its softening point correlates with the temperature distribution. Therefore, even when a uniform differential pressure is applied by the negative pressure generating means 81, the deformation increases in areas heated to higher temperatures. As a result, the presence of a temperature difference TD0 causes the shape symmetry of the glass oscillator to break down, which is a problem.

[0033] (effect) The effects of the melt molding apparatus 1 of this embodiment will be explained. Figure 6 shows a cross-sectional side view of the melt molding apparatus 1 of this embodiment. The contents of Figures 6(A) and (B) are the same as those of Figures 5(A) and (B) described above. According to the melt molding apparatus 1 of this embodiment, the central part FC1 of the flame FL1 can be arranged rotationally symmetrically around the support column 20p. A heat input profile IP1 can be realized such that a peak PP1 exists on the outer circumference of the support column 20p. This makes it possible to have two directions for heat conduction: one from the central part FC1 towards the support column 20p (see arrow Y1) and one from the central part FC1 towards the outer circumference (see arrow Y2). Since the distance from the central part FC1 to the heat conduction path HP1 can be reduced, the effect of heat escaping to the outer circumference can be suppressed. In addition, heating can be performed so that heat accumulates from the central part FC1 towards the support column 20p. As a result, the temperature difference TD1 between the support column 20p and the edge 20m of the hole 20h in the temperature distribution TP1 of the quartz plate 30 can be made smaller than the conventional temperature difference TD0 (see Figure 6(B)). Having a smaller temperature difference TD1 reduces the localized difference in ease of melting and deformation, making it possible to manufacture a glass oscillator with good shape symmetry. Furthermore, even if an axial misalignment occurs between the burner central axis BA (i.e., the center FC1 of the flame FL1) and the molding die 20 central axis CA, it is possible to suppress the occurrence of asymmetry in the shape of the glass oscillator.

[0034] By simply replacing the burner nozzles of the 50 burner and 50t tube, the central part FC1 of the flame FL1 can be positioned around the support column 20p. This simple operation makes it possible to improve the shape symmetry of the glass oscillator.

[0035] Since the peak heat input PP1 can be positioned on the outer circumference of the support column 20p, the temperature rise of the support column 20p can be suppressed. This suppresses deterioration and shrinkage of the support column 20p, thereby increasing the durability of the mold 20.

[0036] (Modified version of Example 1) The edges of the annular outer opening OT1 are not limited to a straight shape as shown in Figure 3(A), but can have various shapes. For example, as shown in Figure 7, it may have a wavy inner edge 50i. The wavy shape of the edge 50e may be an acute angle shape formed by combining straight lines, as shown in Figure 7, or a gentle shape formed by combining curves. Furthermore, the wavy shape may be formed on either the inner edge 50i or the outer edge 50o, or on both.

[0037] Let me explain the effect. By making the annular edge wavy, the opening width can be periodically increased or decreased in the circumferential direction. Since the region with a narrow opening width can function as a flow straightening plate, it is possible to keep the gas ejection state from the outer opening OT1 constant. [Examples]

[0038] Figure 8 shows a plan view of the burner tip 250s of Example 2. Example 2 differs from Example 1 in the shape and arrangement of the outer peripheral opening. Parts common to the melt molding apparatus 1 of Example 1 are given the same reference numerals, and their explanation is omitted.

[0039] The burner tip 250s has four outer peripheral openings OT201 arranged rotationally symmetrically around the burner central axis BA. When viewed from the direction of the burner central axis BA (+z direction), the outer peripheral openings OT201 surround the support column 20p and the hole 20h, and do not overlap with the support column 20p and the hole 20h. By providing such outer peripheral openings OT201, the center of the flame can be arranged rotationally symmetrically around the support column 20p. Thus, it becomes possible to manufacture a glass oscillator with good shape symmetry.

[0040] (Modified version of Example 2) The number of outer peripheral openings is not limited to four and may vary. Also, the number of rows of outer peripheral openings surrounding the burner central axis BA is not limited to one row, but may be two or more rows. Furthermore, the opening area of ​​the multiple outer peripheral openings is not limited to a constant and may vary. Figure 9 shows a modified example of Embodiment 2. Six outer peripheral openings OT202, OT203, and OT204 are arranged at the burner tip 250s. The outer peripheral openings OT202 are arranged rotationally symmetrically on the first row L1, which is the circumference of a circle with radius R1. The outer peripheral openings OT203 are arranged rotationally symmetrically on the second row L2, which is the circumference of a circle with radius R2. The outer peripheral openings OT204 are arranged rotationally symmetrically on the third row L3, which is the circumference of a circle with radius R3. Radius R1 is the minimum, radius R3 is the maximum, and radius R2 is in between. The opening area is smallest for outer peripheral opening OT202, largest for outer peripheral opening OT204, and in between for outer peripheral opening OT203. In other words, the opening area of ​​each of the multiple outer peripheral openings increases as the radial distance from the burner central axis BA increases. Let's explain the effect. As the radial distance increases, the circumference also increases, so if the number of outer peripheral openings arranged on the circumference remains constant, the density of outer peripheral openings on the circumference decreases. Therefore, by increasing the opening area in accordance with the decrease in density, the gas ejection rate can be increased. This makes it possible to suppress the situation in which differences in heat generation occur due to differences in density.

[0041] The shape of the outer opening is not limited to a circle; it can be various. For example, polygonal shapes, elliptical shapes, etc., can be used. [Examples]

[0042] Figure 10 shows a plan view of the burner tip 350s of Example 3. Example 3 differs from Example 1 in that it further includes a central opening. Parts common to the melt molding apparatus 1 of Example 1 are given the same reference numerals, and their explanation is omitted.

[0043] In addition to the outer peripheral opening OT1, a central opening CT2 is located at the burner tip 50s. The central opening CT2 is positioned to include the burner's central axis BA. The opening area of ​​the central opening CT2 is smaller than the opening area of ​​the outer peripheral opening OT1. Furthermore, when viewed from the direction of the burner's central axis BA (+z direction), the outer peripheral opening OT201 overlaps with the support column 20p.

[0044] As shown in Figure 10(B), the upper part of the central opening CT2 is connected to the gas supply path to the outer opening OT1 (see region AR1). This allows a portion of the gas supplied to the outer opening OT1 to be branched and ejected from the central opening CT2. A stable pilot flame can be formed in the central opening CT2. The effect of pilot flame retention makes it possible to improve the extinction limit performance.

[0045] In this embodiment, the opening area of ​​the central opening CT2 is made smaller than the opening area of ​​the outer periphery opening OT1. This makes it possible to form a flame with a peak in heat input on the outer periphery of the support column 20p.

[0046] (Modified version of Example 3) There are various ways in which the opening area of ​​the central opening can be made smaller than the opening area of ​​the outer periphery opening. For example, the diameter of the central opening may be smaller than the diameter of the outer periphery opening. The number of central openings may be less than the number of outer periphery openings. The arrangement density of central openings may be less than the arrangement density of outer periphery openings. Alternatively, a combination of these configurations may be used. [Examples]

[0047] Example 4 differs from Example 1 in that the position of the flame in the planar direction is moved. Parts common to the melting molding apparatus 1 of Example 1 are given the same reference numerals, and their explanation is omitted. Figure 11 shows a cross-sectional side view of the melting molding apparatus 401 of Example 4. The contents of Figure 11 are the same as those of Figure 6 of Example 1.

[0048] The melt molding apparatus 401 is equipped with a burner 450. The burner 450 is a conventional burner having an opening at the burner central axis BA. The movable mechanism 53 of Embodiment 4 has the function of moving the position of the burner tip 450s in a two-dimensional xy plane while maintaining a substantially constant distance between the burner tip 450s and the upper surface 20s of the mold 20.

[0049] In the heating process of step S50, the control unit 70 moves the position of the burner tip 450s in a two-dimensional xy plane. The movement trajectory of the flame FL1 at this time is a rotationally symmetric trajectory about the central axis CA and is a single-stroke trajectory. Also, when viewed from the direction of the central axis CA (+z direction), the movement trajectory of the flame FL1 does not intersect with the support column 20p. In this embodiment, as shown in Figure 10, the movement trajectory TR1 is a circular trajectory about the central axis CA. This makes it possible to realize a heat input profile IP1 having a concentric peak PP1 with respect to the central axis CA. As a result, it is possible to make the temperature difference TD1 in the temperature distribution TP1 of the quartz plate 30 smaller than the conventional temperature difference TD0.

[0050] (Modification of Example 4) The method of moving the flame is not limited to moving the burner, but can be various. For example, the mold 20 may be rotated around the central axis CA with the central axis CA of the mold 20 and the central axis BA of the burner eccentrically aligned. This also makes the flame's trajectory a circular trajectory centered on the central axis CA. Alternatively, for example, multiple electrodes may be arranged to surround the area where the flame is generated. Since the flame contains positive ions, it has the property of being attracted to electrodes to which a negative voltage is applied. Therefore, by applying a negative voltage to an electrode located in the direction to which the flame is to be moved, it is possible to move the flame in the xy plane.

[0051] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. Furthermore, the technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness.

[0052] (modified version) The material of the mold 20 is not limited to graphite. Various materials, such as boron nitride, can be used as long as they possess the required thermal shock resistance and thermal conductivity. Furthermore, the material of the oscillator is not limited to fused silica. Any dielectric material that undergoes melt deformation may be used.

[0053] The following are embodiments of this technology. [Aspect 1] A melt molding die comprising a flat top surface, a hole having a cylindrical shape hollowed out around a first axis perpendicular to the top surface and having a bottom surface, and a support column extending upward from the bottom surface of the hole around the first axis, A burner having a second axis coaxial with the first axis, positioned above the melting mold, and configured to generate a flame from its tip toward the hole, A melt molding apparatus comprising, The tip portion has a first opening configured to eject fuel gas, which is arranged rotationally symmetrically around the second axis. When viewed from the direction of the second axis, the first opening surrounds the support column and the first opening does not overlap with the support column. Melt molding apparatus. [Aspect 2] The melt molding apparatus according to embodiment 1, wherein the first opening is an annular shape centered on the second axis. [Aspect 3] The melt molding apparatus according to embodiment 2, wherein the annular first opening has a wavy edge. [Aspect 4] Multiple first openings are provided, The melt molding apparatus according to embodiment 1, wherein a plurality of the first openings are arranged rotationally symmetrically with respect to the second axis. [Aspect 5] The melt molding apparatus according to embodiment 4, wherein the opening area of ​​each of the plurality of first openings increases with increasing distance from the second axis. [Aspect 6] It further comprises a second opening positioned at the tip portion so as to include the second axis, The first opening is arranged around the second opening, The melt molding apparatus according to any one of embodiments 1-5, wherein the opening area of ​​the second opening is smaller than the opening area of ​​the first opening. [Aspect 7] A melting molding apparatus according to any one of embodiments 1-6, wherein, when viewed from the direction of the second axis, the first opening surrounds the outer circumference of the hole and the first opening does not overlap the hole. [Aspect 8] A melt molding die comprising a flat top surface, a hole having a cylindrical shape hollowed out around a first axis perpendicular to the top surface and having a bottom surface, and a support column extending upward from the bottom surface of the hole around the first axis, A burner having a second axis coaxial with the first axis, positioned above the melting mold, and configured to generate a flame from its tip toward the hole, A melt molding apparatus comprising, The temperature distribution of the flame on the plane including the upper surface has a distribution where the temperature around the second axis is higher than the temperature of the second axis. Melt molding apparatus. [Aspect 9] A melt molding die comprising a flat top surface, a hole having a cylindrical shape hollowed out around a first axis perpendicular to the top surface and having a bottom surface, and a support column extending upward from the bottom surface of the hole around the first axis, A burner is positioned above the melting mold and has a tip that is positioned opposite the hole, and is configured to generate a flame from the tip toward the hole. A flame position control unit controls the position of the flame so that it can move in a planar direction parallel to the upper surface, A method for manufacturing a vibrator using a melt molding apparatus equipped with the following: The arrangement step involves placing a plate-shaped workpiece on the upper surface so as to cover the hole, The process of generating a flame from the tip, A heating step in which the flame position control unit moves the position of the flame in the planar direction along a rotationally symmetrical trajectory about the first axis, Equipped with, When viewed from the direction of the first axis, the trajectory does not intersect with the support column. A method for manufacturing an oscillator. [Explanation of symbols]

[0054] 1: Melt molding apparatus 20: Molding mold 20h: Hole 20p: Support column 20s Top surface 30: Quartz plate 50: Burner 50s: Burner tip BA: Burner central axis CA: Central axis OT1: Outer circumference opening

Claims

1. A melting mold comprising a flat top surface, a hole having a cylindrical shape hollowed out around a first axis perpendicular to the top surface and having a bottom surface, and a support column extending upward from the bottom surface of the hole around the first axis, A burner having a second axis coaxial with the first axis, positioned above the melting mold, and configured to generate a flame from its tip toward the hole, A melt molding apparatus comprising, The tip portion has a first opening configured to eject fuel gas, which is arranged rotationally symmetrically around the second axis. When viewed from the direction of the second axis, the first opening surrounds the support column and the first opening does not overlap with the support column. Melt molding apparatus.

2. The melt molding apparatus according to claim 1, wherein the first opening is an annular shape centered on the second axis.

3. The melt molding apparatus according to claim 2, wherein the annular first opening has a wavy edge.

4. Multiple first openings are provided, The melt molding apparatus according to claim 1, wherein a plurality of the first openings are arranged rotationally symmetrically with respect to the second axis.

5. The melt molding apparatus according to claim 4, wherein the opening area of ​​each of the plurality of first openings increases as the distance from the second axis increases.

6. It further comprises a second opening positioned at the tip portion so as to include the second axis, The first opening is arranged around the second opening. The melt molding apparatus according to claim 1, wherein the opening area of ​​the second opening is smaller than the opening area of ​​the first opening.

7. The melt molding apparatus according to claim 1, wherein, when viewed from the direction of the second axis, the first opening surrounds the outer circumference of the hole and the first opening does not overlap the hole.

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