JP7359734B2 - Molded plate, quartz glass crucible manufacturing device, and quartz glass crucible manufacturing method - Google Patents

Description

The present invention relates to a molded plate used in a quartz glass crucible manufacturing apparatus, a quartz glass crucible manufacturing apparatus, and a quartz glass crucible manufacturing method.

BACKGROUND ART Conventionally, a method called the so-called Czochralski method (CZ method) has been widely adopted for manufacturing single crystal substances such as single crystal semiconductor materials. In this method, when producing a single-crystal silicon ingot, polycrystalline silicon is melted in a container, the end of a seed crystal is immersed in the molten bath (melt), and the seed crystal is pulled up while being rotated. In this method, a single crystal with the same crystal orientation grows under a seed crystal. When pulling single crystal silicon, a quartz glass crucible is generally used as the single crystal pulling container. A quartz glass crucible for carrying out such a CZ method generally has an outer layer made of opaque quartz glass containing bubbles and an inner layer made of transparent quartz glass that does not substantially contain bubbles. used.

The manufacturing method for such a quartz glass crucible involves forming a molded body (raw material powder molded body) of silica powder (raw material powder) in a mold (form) by the action of centrifugal force, and then using a heat source such as an arc to form a molded body (raw material powder molded body). A method of melting is known. Also known is a manufacturing method in which silica powder is further supplied into the mold during melting, and the silica powder is sprayed onto the inner surface of the outer layer while being melted by an arc. As methods for manufacturing these quartz glass crucibles, there are techniques disclosed in Patent Documents 1 to 7, for example.

Patent Document 1 describes a structure in which a cylindrical rim piece is hooked and supported inside the upper opening of a mold via a hook. Furthermore, Patent Document 2 discloses that a core is inserted into the inside of a rotating mold, quartz powder is filled between the core and the inner surface of the mold, and that the core is inserted after being filled with the quartz powder. It is described that the material is pulled up and then subjected to heat treatment. Patent Document 3 describes that an inner frame is used when supplying the quartz glass raw material powder, and the quartz glass raw material powder is supplied between the outer frame and the inner frame. Patent Document 4 describes a method for manufacturing a silica glass container including a flat molding plate for molding raw material powder supplied into a mold. Patent Document 5 describes that a quartz glass molded body is formed by spraying quartz glass raw material powder into a rotating crucible mold in a non-heated and non-melting environment.

Patent Document 6 discloses that a ring-shaped heat insulating barrier material (quartz, carbon , silicon carbide or silicon nitride) is described. Patent Document 6 describes the effect that this makes it possible to reduce the portion to be cut and removed by reducing the diameter and thinning of the crucible, and as a result, it is possible to reduce raw material costs and ultimately product costs.

Patent Document 7 describes that when molding silica particles supplied into a mold into the shape of a crucible, a "spatula" (one that molds the particles into a desired shape) may be pressed against the silica particles. Are listed.

Japanese Patent Application Publication No. 2010-163312 Japanese Patent Application Publication No. 06-279167 Japanese Patent Application Publication No. 2000-169164 Japanese Patent Application Publication No. 2005-289710 JP 2017-149603 Publication Japanese Patent Application Publication No. 2010-105890 JP2009-040680A

In the production of quartz glass crucibles by heating and melting raw quartz powder as described above, in recent years the introduction of manufacturing equipment for large crucibles to accommodate the production of large diameter wafers has become expensive, and various crucible sizes and sizes have been developed to accommodate various wafer qualities. From the perspective of differentiating structures, it has become essential to improve productivity, typified by faster changeovers of production equipment. At the same time, basic demands on the manufacturing industry, such as saving raw materials, which are natural resources, and reducing waste, are becoming increasingly important.

The present invention was developed in view of these circumstances, and aims to flexibly mold raw material powder in a mold in order to improve productivity, save raw materials, and reduce waste while meeting various customer demands. The purpose is to provide a molded plate that can change the body shape. Another object of the present invention is to provide a method for manufacturing a quartz glass crucible that allows the shape of the upper part of the molded body to be freely changed when heating and melting the raw material powder molded body supplied into the mold.

The present invention has been made to solve the above problems, and includes a rotatable mold and a raw material powder supply means for supplying raw material powder to the mold, and the raw material powder supply means is provided inside the mold. In an apparatus that molds the supplied raw material powder into a crucible-shaped raw material powder molded body and melts the raw material powder molded body to produce a quartz glass crucible, a molding used for molding the raw material powder molded body. The molding plate is a plate, and the molding plate has a shape corresponding to the shape of the inner surface of the raw material powder molding, and is arranged inside the mold so that the mold is positioned relative to the molding plate. The raw material powder supplied into the mold is molded into the crucible shape by rotation, and the molding plate includes a molding plate main body and an edge plate that is removably attached to the molding plate main body, The edge plate has a shape corresponding to the shape of the surface at the upper end of the raw material powder molded body at a position facing the upper end of the raw material powder molded body when the molding plate is placed inside the mold. To provide a molded plate characterized by:

Forming plates with such edge plates can accommodate a variety of dimensional specifications while reducing the amount of changeover time and raw material powder.In order to achieve both reduction in changeover time and reduction in raw material powder, the forming plate has raw material powder added to it in advance when molding the raw material powder molded body. It can be molded.

In this case, it is preferable that the edge plate has a notch oblique to the thickness direction of the raw material powder molded body.

In this way, since the edge plate has the diagonal notch, the upper part of the raw material powder molded body can be molded with a more stable shape.

Further, it is preferable that at least a portion of the molded plate main body and the edge plate in contact with the raw material powder molded body is made of quartz glass.

In this way, the molding plate whose portion in contact with the raw material powder molded body is made of quartz glass can more effectively suppress the contamination of impurities into the raw material powder molded body.

In addition to the edge plate, the molded plate of the present invention further includes an additional plate that is detachable from the molded plate body, and the additional plate changes the shape of the inner surface of the raw material powder molded body. It can be made possible.

By providing the molding plate with such an additional plate, the shape of the raw material powder molded body can be finely changed according to specifications.

In this case, it is preferable that when the molding plate is placed inside the mold, the additional plate is located in a crucible-shaped straight body portion of the raw material powder molded body.

By positioning the additional plate in this manner, the shape of the raw material powder molded body can be changed in the crucible-shaped straight body portion of the raw material powder molded body.

Furthermore, the present invention provides a quartz glass crucible manufacturing apparatus comprising the mold, the raw material powder supply means, and the molding plate.

This kind of quartz glass crucible manufacturing equipment uses a molding plate equipped with an edge plate so that the heat distribution inside the mold can be controlled when heating and melting the raw material powder molded body in the mold. , the raw material powder can be molded in advance.

In this case, the quartz glass crucible manufacturing apparatus of the present invention changes the shape at the upper end of the raw material powder molded body by replacing the edge plate or changing the attachment position of the edge plate. It can be made possible.

In this way, the quartz glass crucible manufacturing equipment, which can change the shape of the upper end of the raw material powder molded body by replacing or changing the position of the edge plate, can adjust the raw material powder according to the specifications of the quartz glass crucible to be manufactured. The shape of the molded body can be easily and finely adjusted.

Furthermore, in this case, the shape of the upper end of the raw material powder molded body is changed by replacing the edge plate or changing the attachment position of the edge plate, thereby producing a quartz glass crucible by melting the raw material powder molded body. It may be possible to change the height of the

With such a quartz glass crucible manufacturing apparatus, the height of the quartz glass crucible can be changed easily and at low cost according to specifications.

Further, the present invention provides the raw material powder by supplying the raw material powder inside a rotatable mold, arranging a molding plate inside the mold, and rotating the mold relatively to the molding plate. A quartz glass crucible for manufacturing a quartz glass crucible, comprising a step of molding powder into a raw material powder molded body in a crucible shape corresponding to the shape of the mold plate and the mold, and a step of melting the raw material powder molded body. In the manufacturing method, the molding plate has a surface shape at the upper end of the raw material powder molding at a position facing the upper end of the raw material powder molding when the molding plate is placed inside the mold. Provided is a method for producing a quartz glass crucible, characterized in that a raw material powder molded body is molded using an edge plate having a corresponding shape installed on a molding plate body.

This method of manufacturing a quartz glass crucible by molding a raw material powder molded body using a molding plate equipped with such an edge plate and heating and melting it allows the shape of the upper part of the raw material powder molded body to be flexibly controlled. This makes it possible to reduce set-up time and raw material powder while accommodating a variety of dimensional specifications.

In this case, it is preferable to use, as the edge plate, one having a notch oblique to the thickness direction of the raw material powder molded body.

In this way, by using the edge plate having the diagonal notch, the upper part of the raw material powder molded body can be molded with a more stable shape.

Moreover, it is preferable to use as the molded plate main body and the edge plate at least a portion of which is in contact with the raw material powder molded body made of quartz glass.

By using such a molding plate whose portion in contact with the raw material powder molded body is made of quartz glass, it is possible to more effectively suppress contamination of impurities into the raw material powder molded body.

Furthermore, an additional plate may be installed on the molding plate in addition to the edge plate, and the shape of the inner surface of the raw material powder molded body can be changed by the additional plate.

By using a molding plate having an additional plate in this way, the shape of the raw material powder molded body can be finely changed according to specifications.

In this case, when the molding plate is arranged inside the mold, the additional plate can be positioned in the crucible-shaped straight body part of the raw material powder molded body.

By positioning the additional plate in this manner, the shape of the raw material powder molded body can be changed in the crucible-shaped straight body portion of the raw material powder molded body.

Further, in the method for manufacturing a quartz glass crucible of the present invention, the shape at the upper end of the raw material powder molded body is changed by replacing the edge plate or by changing the attachment position of the edge plate. I can do it.

In this method of manufacturing a quartz glass crucible, the shape of the upper end of the raw material powder molded body can be changed by replacing or changing the position of the edge plate, the raw material powder is changed according to the specifications of the quartz glass crucible to be manufactured. The shape of the molded body can be easily and finely adjusted.

In this case, by changing the shape of the upper end of the raw material powder molded body by replacing the edge plate or changing the attachment position of the edge plate, the quartz glass crucible manufactured by melting the raw material powder molded body is Height can be changed.

This method of manufacturing a quartz glass crucible allows the height of the quartz glass crucible to be easily changed at low cost according to specifications.

Since the present invention uses a molding plate that includes a molding plate main body and an edge plate that can be detached from the molding plate body, the shape of the upper end of the raw material powder molded body can be changed by replacing or changing the position of the edge plate rather than the entire molding plate. Therefore, the shape of the raw material powder molded body can be finely adjusted according to the specifications of the quartz glass crucible to be manufactured. Furthermore, the shape specifications of the quartz glass crucible can be met by replacing or changing the position of the edge plate, leading to improved productivity and reduced manufacturing costs of the quartz glass crucible. Furthermore, the presence of the edge plate can prevent the raw material powder from flying out of the mold during molding of the raw material powder molded body in the upper part of the mold, so that wasted raw material powder can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of a quartz glass crucible manufacturing apparatus equipped with a molded plate of the present invention. FIG. 2 is a schematic diagram of the positional relationship between the molded plate and the raw material powder molded body of the present invention, viewed from above in the vertical direction. FIG. 2 is a schematic diagram showing an example of a manufacturing apparatus for a quartz glass crucible equipped with a molded plate of the present invention, in which the position of an edge plate is changed from that in FIG. 1 . FIG. 2 is a schematic diagram showing another example of a quartz glass crucible manufacturing apparatus equipped with a molded plate of the present invention. FIG. 1 is a schematic diagram showing an example of a quartz glass crucible manufacturing apparatus equipped with a conventional molded plate.

As mentioned above, in the conventional manufacturing of quartz glass crucibles, the height of the quartz glass crucibles differs depending on the specifications required by each customer. In order to meet the specifications with one mold, it was necessary to cut the upper end of the quartz glass crucible for each specification, and it was necessary to change the amount of the cut section. As a result, when the amount of cut portions is large, it becomes a factor that lowers the yield. For this reason, each company had to own a mold for forming raw material powder moldings that met each customer's specifications. Furthermore, man-hours are required to replace the mold, which is a factor that deteriorates productivity.

In addition to the method of preparing a plurality of molds, a lower-cost method of preparing a plurality of molded plates was also being adopted. However, the time required to replace, adjust, and test melt large molded plates still had a significant impact on productivity. In addition, for one-off prototype production, such as the prototyping of crucibles for testing by customers, which has been increasing in recent years, further ideas are required in terms of lead time and cost for preparing large molded plates. was.

In view of this, the present inventor came up with the idea of using a molding plate having an edge plate that is removable from the molding plate main body, which allows the shape of the molding plate at the upper part of the mold to be changed, and completed the present invention. Ta.

The molding plate of the present invention includes a rotatable mold and a raw material powder supplying means for supplying raw material powder to the mold, and the raw material powder supplied by the raw material powder supplying means to the inside of the mold is placed in a crucible. In an apparatus for manufacturing a quartz glass crucible by molding raw material powder into a shaped raw material powder molded body and melting the raw material powder molded body, the molding plate is used for molding the raw material powder molded body, the molding plate is , has a shape corresponding to the shape of the inner surface of the raw material powder molded body, is placed inside the mold, and is supplied into the mold by rotating the mold relative to the molding plate. The raw material powder is molded into the crucible shape, and the molding plate includes a molding plate main body and an edge plate that is removable from the molding plate main body, and the edge plate includes a molding plate that is A molding having a shape corresponding to the shape of the surface at the upper end of the raw material powder molded body at a position facing the upper end of the raw material powder molded body when placed inside the mold. It is a board.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows a quartz glass crucible manufacturing apparatus 50 equipped with a molded plate 10 of the present invention. Moreover, FIG. 2 shows a schematic diagram of the positional relationship of the molded plate of the present invention with respect to the raw material powder molded body, viewed from above in the vertical direction. In FIG. 2, illustration of the mold is omitted for ease of viewing. As shown in FIGS. 1 and 2, the quartz glass crucible manufacturing apparatus 50 includes a rotatable mold 20 and a raw material powder supply means 30 that supplies raw material powder to the mold 20. The quartz glass crucible manufacturing apparatus 50 molds the raw material powder supplied by the raw material powder supply means 30 inside the mold 20 into a crucible-shaped raw material powder molded body 44, and melts the raw material powder molded body 44 to form quartz. This is a device for manufacturing glass crucibles. 1 and 2 show how the raw material powder 42 is supplied from the raw material powder supply means 30.

The molding plate 10 of the present invention is a molding plate used for molding a raw material powder molded body in this quartz glass crucible manufacturing apparatus 50. This molding plate 10 has a shape corresponding to the shape of the inner surface of the raw material powder molded body 44, and is arranged inside the mold 20 so that the mold 20 rotates relative to the molding plate 10. The raw material powder 42 supplied into the mold 20 is molded into a crucible shape. The molded plate 10 of the present invention includes a molded plate main body 12 and an edge plate 14 that is detachable from the molded plate main body. This edge plate 14 has a shape corresponding to the shape of the surface at the upper end of the raw material powder molded body 44 at a position facing the upper end of the raw material powder molded body 44 when the molding plate 10 is placed inside the mold 20. It has the following.

Furthermore, the quartz glass crucible manufacturing apparatus 50 of the present invention is characterized by comprising a mold 20, a raw material powder supply means 30, and a molding plate 10.

By using the molding plate 10 having such an edge plate 14, a desired raw material powder shape can be prepared when heating and melting the raw material powder molded body 44 in the mold 20 of the quartz glass crucible manufacturing apparatus 50. I can do it. The method of installing the edge plate 14 on the molded plate main body 12 is not particularly limited, and may be screwed or the like.

In the quartz glass crucible manufacturing apparatus 50 of the present invention, the shape of the upper end of the raw material powder molded body 44 can be changed by replacing the edge plate 14 or by changing the attachment position of the edge plate 14. It can be made possible. Thereby, the shape of the raw material powder molded body 44 can be easily and finely adjusted depending on the quartz glass crucible to be manufactured.

In particular, the quartz glass crucible manufacturing apparatus 50 of the present invention can produce a raw material powder molded body by changing the shape of the upper end of the raw material powder molded body 44 by replacing the edge plate 14 or changing the attachment position of the edge plate 14. The height of the quartz glass crucible manufactured by melting 44 can be changed. Such a quartz glass crucible manufacturing apparatus 50 can easily change the height of the quartz glass crucible according to specifications.

FIG. 3 shows an example in which the position of the edge plate 14 is changed from FIG. 1. By changing the position of the edge plate 14 in this manner, the shape of the upper end portion of the raw material powder molded body 44 can be changed. Moreover, in particular, the height of the raw material powder molded body 44 can be changed. Moreover, such changes in shape and height can also be performed by replacing the edge plate 14. That is, by preparing a plurality of edge plates 14 having different shapes, the edge plates 14 can be replaced as needed.

Further, as shown in FIGS. 1 and 3, in the molded plate 10 of the present invention, it is preferable that the edge plate 14 has a notch oblique to the thickness direction of the raw material powder molded body 44. In this way, since the edge plate has the diagonal notch, the raw material powder molded body can be molded with a stable upper part shape.

Since the shape of the upper part of the raw material powder molded body 44 can be controlled by the molding plate 10 and the quartz glass crucible manufacturing apparatus 50 equipped with the edge plate 14 of the present invention, this shape can be made into a regular shape. be able to. Moreover, according to the present invention, a silica glass crucible of a desired height can be obtained by simply changing the height of the edge plate 14 for each specification. That is, there is no need to replace the mold 20 for each customer's specifications for the quartz glass crucible, improving productivity. Therefore, there is no need to keep a plurality of molds in stock. Further, when the raw material powder molded body 44 is molded on the inner surface of the mold 20, the amount of the raw material powder 42 that flies out of the mold 20 at the upper part of the mold 20 can be reduced. Therefore, it also leads to a reduction in the manufacturing cost of the quartz glass crucible. The amount of raw material powder saved depends on the customer's specifications (diameter and height of the quartz glass crucible), but it is approximately 3% for a 22 inch (approx. 56 cm) diameter crucible, and approximately 3% for a 32 inch (approximately 81 cm) diameter crucible. With a crucible, it can be reduced by about 5%.

Further, in the molded plate 10 of the present invention, it is preferable that at least the portion of the molded plate main body 12 and the edge plate 14 in contact with the raw material powder molded body 44 be made of quartz glass. The molding plate 10 whose portion in contact with the raw material powder molded body 44 is made of quartz glass can suppress the mixing of impurities into the raw material powder molded body 44 . The parts of the molded plate main body 12 and the edge plate 14 that are not in contact with the raw material powder molded body 44 may be made of other materials, such as stainless steel. This improves shape accuracy and strength, and allows for inexpensive construction.

Further, as shown in FIG. 4, in addition to the edge plate 14, the molded plate 10 of the present invention may further include an additional plate 16 that is detachable from the molded plate main body 12. In this case, the additional plate 16 can change the shape of the inner surface of the raw material powder molded body 44. By providing the molding plate 10 with such an additional plate 16, the shape of the raw material powder molded body 44 can be finely changed according to specifications. Similarly to the molded plate main body 12 and the edge plate 14, the additional plate 16 is preferably made of quartz glass at least at the portion that contacts the raw material powder molded body 44.

Further, as shown in FIG. 4, when the molding plate 10 is placed inside the mold 20, it is preferable that the additional plate 16 be located in the crucible-shaped straight body part of the raw material powder molded body 44. . Thereby, the shape of the raw material powder molded body 44 can be changed in the crucible-shaped straight body portion of the raw material powder molded body 44. In particular, when the manufactured quartz glass crucible is used for manufacturing silicon single crystals by the Czochralski method, the thickness of the layer at a specific location in the body of the quartz glass crucible can be changed. For example, if grooves 46 are formed in the raw material powder molded body 44 using the additional plate 16, the opaque silica glass layer can be thinned only near the melt surface of the silicon melt before the silicon single crystal starts to be pulled, and the transparent silica glass layer in the inner layer can be thinned. It becomes possible to form a thick glass layer.

The present invention also provides a method for manufacturing a quartz glass crucible. This method can be performed using a quartz glass crucible manufacturing apparatus 50 as shown in FIGS. 1 to 4, and will therefore be described with reference to FIGS. 1 to 4. The method of the present invention includes supplying raw material powder 42 inside a rotatable mold 20, arranging a molding plate 10 inside the mold 20, and rotating the mold 20 relative to the molding plate 10. , a step of molding the raw material powder 42 into a crucible-shaped raw material powder molded body 44 corresponding to the shape of the molding plate 10 and the mold 20 (step a), and a step of melting the raw material powder molded body 44 (step b). and manufactures quartz glass crucibles. In the method of the present invention, furthermore, in the step a, the molded raw material powder is placed at a position facing the upper end of the molded raw material powder 44 as the molded plate 10 when the molded plate 10 is placed inside the mold. The raw material powder molded body 44 is molded using an edge plate 14 having a shape corresponding to the shape of the surface at the upper end of the raw material powder molded body 44 installed on the molding plate main body 12.

In the method for manufacturing a quartz glass crucible of the present invention, the shape of the raw material powder molded body 44 at the upper end can be changed by replacing the edge plate 14 or by changing the attachment position of the edge plate 14. . In particular, by changing the shape of the upper end of the raw material powder molded body 44 by replacing the edge plate 14 or changing the attachment position of the edge plate 14, quartz glass manufactured by melting the raw material powder molded body 44 can be manufactured. The height of the crucible can be changed.

Furthermore, as described above, in order to suppress the contamination of impurities into the raw material powder molded body, the molding plate main body 12 and the edge plate 14 should be made of quartz glass at least at the portion that contacts the raw material powder molded body 44. is preferred.

Furthermore, by using an edge plate 14 having a notch diagonal to the thickness direction of the raw material powder molded body 44, the upper part of the raw material powder molded body 44 can be molded in a stable shape. .

The melting method in step b above is not particularly limited, and any known method can be used. Specifically, after removing the molding plate 10 and the raw material powder supply means 30 from the inside of the mold 20, a carbon electrode is inserted into the mold 20 and arc discharge is performed to heat and melt the raw material powder molded body 44. be able to. By using a mold that can be sucked outward as the mold 20, heating and melting can be performed while sucking. In addition, an inner layer made of transparent silica glass may be formed by supplying synthetic quartz powder to the inside of the mold 20 at the same time when these are heated and melted.

Further, as shown in FIG. 4, in the method for manufacturing a quartz glass crucible of the present invention, in addition to the edge plate 14, an additional plate 16 is installed on the molding plate 10, and the raw material powder molded body 44 is molded. It can be carried out. This additional plate 16 allows the shape of the inner surface of the raw material powder molded body 44 to be changed. In particular, when the molding plate 10 is placed inside the mold 20, the additional plate 16 can be positioned in the crucible-shaped straight body portion of the raw material powder molded body 44.

As described above, in the method for manufacturing a quartz glass crucible of the present invention, when heating and melting the raw material powder molded body 44 in the mold 20, the raw material powder is prepared in advance in the upper part of the mold 20 so that a desired shape is obtained after melting. Powder can be molded.

In order to obtain the same effect as the present invention, if the molding plate itself is replaced, it is necessary to set the molding thickness according to customer specifications (thickness) on the molding plate itself. When such an integral molded plate is replaced, it is necessary to adjust the molding thickness in addition to the installation time, and the productivity is correspondingly worse than that of the present invention. According to the present invention, only the edge plate 14 needs to be replaced, and can be replaced in a short time. The reason why it takes time to use an integrated molded plate is that there are a large number of jigs to fix the plate, and it is necessary to position the mold and the molded plate to optimize the gap between them. Furthermore, it is necessary to manufacture a plurality of integrated molded plates according to customer specifications (especially height), and the manufacturing cost is estimated to be several times that of the case of only edge plates.

In addition, when using an integrally molded plate and using the same mold, the barrier material described in Patent Document 6 must be manufactured in multiple pieces according to customer specifications (height), and the material and size may vary. However, it is likely to be extremely expensive. Further, Patent Document 6 states that the barrier material is consumed by being used multiple times, and costs are incurred each time it is replaced. This is because the barrier material is heated while it is placed in the mold. There is also a concern that the way heat is applied to the raw material powder molded body will change due to the wear and tear of the barrier material. On the other hand, the edge plate 14 of the present invention is used only when molding the raw material powder molded body 44, and although it is subject to wear and tear with the raw material powder, by adjusting the position and setting the molding thickness each time, the edge plate 14 is used only when molding the raw material powder molded body 44. The shape can be made constant, and the heat applied during melting of the raw material powder molded body 44 can be made uniform.

EXAMPLES Below, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples.

[Example 1]
A raw material powder molded body 44 is molded using a quartz glass crucible manufacturing apparatus 50 equipped with a molded plate 10 having an edge plate 14 as shown in FIGS. A quartz glass crucible with a diameter of 81 cm) was manufactured.

Regarding the 32-inch diameter crucible, there are at least three different specifications of the crucible with different heights. Compared to crucible specification A, which is the tallest, specification B is 50 mm lower in height than A, and specification C is 80 mm lower in height than A. When manufacturing specification A, molded plate A without an edge plate is used, and when manufacturing specifications B and C, edge plates B and C corresponding to the respective heights are attached to the above-mentioned molded plate A, and dozens of each are manufactured. The process of melting the crucible was repeated three times. Table 1 summarizes the difference in the weight of molding raw materials, the time required for changeover between specifications, and the number of pieces melted in a crucible test to determine the dimensions after changeover. The setup change time refers to the time from the end of production and melting of A to the start of production and melting of B, and the time from the end of production and melting of B to the start of production and melting of C.

[Comparative example 1]
A raw material powder molded body 144 was molded using a quartz glass crucible manufacturing apparatus 150 equipped with a conventional molding plate 110 as shown in FIG. 5, and this was heated and melted to manufacture a quartz glass crucible. A conventional molding plate 110 without an edge plate was used. The mold 120 and the raw material powder supply means 130 for supplying the raw material powder 142 are similar to those in the quartz glass manufacturing apparatus 50 shown in FIGS. 1 to 4.

Similarly to Example 1, when manufacturing crucibles of three specifications A to C by repeating the flow of melting several dozen crucibles three times, molded plate A without an edge plate corresponding to specification A Using only a chisel, the production of specifications A to C was handled by changing the end cutting position. This is a conventional manufacturing method. In addition, in accordance with specifications B and C, molded plates B and C were used in which only the upper part of the molded plates protruded toward the outer circumference of the crucible. Tables 2 and 3 show the difference in the weight of molding raw materials for each molding plate, the changeover time, and the number of melted crucibles for dimensioning during this period.

[Result 1]
As can be seen from Example 1 (Table 1) and Comparative Example 1 (Tables 2 and 3), when using the melting device and manufacturing method using an edge plate, the setup change time and the test melting of the crucible after setup change It was possible to reduce the amount of molding raw material without significantly deteriorating the number of molding materials. Since tens of kilograms or more of raw materials are used to manufacture a 32-inch crucible, it is important to reduce raw materials by 3% per crucible.

[Example 2]
Regarding the crucible of specification B in Example 1, the molded layer was moved back 3 mm in the outer circumferential direction at a position of 30 mm to 60 mm from the upper end to form a recessed part in the powder molded layer, and then melted in the crucible using the so-called scattering method. We were asked to create a prototype with a thicker transparent layer inside. Therefore, a trial production was carried out by attaching the edge plate B and the prototypical convex edge plate for forming the above-mentioned recesses to the molded plate A described in Example 1. At that time, Table 4 shows the lead time (number of days) from receiving a request for trial production until preparation for the experiment, the time for changeover from normal production, and the number of melted crucibles for dimensioning.

[Comparative example 2]
Lead time (number of days) from receiving a request for trial production to preparation for experiment, time for changeover from normal production, and dimensions when trial production of the vase in Example 2 was made using a molded plate without an edge plate. The number of melted pieces in the crucible is shown in Table 5.

[Result 2]
As can be seen from Example 2 (Table 4) and Comparative Example 2 (Table 5), when edge plates are used, it is possible to prepare prototypes in a short period of time, and the burden of setup changes is lower than that of replacing the entire molding plate. The result was also small. As for the cost of preparing the prototype, if we used the edge plate in Example 2, the total cost would have been tens of thousands of yen, including the cost of drilling fixing holes in molded plate A and fixing bolts, as well as the material and processing costs for the edge plate. In comparison, in the case of preparing the molded plate in Comparative Example 2, it cost more than 200,000 yen to prepare and process the metal material and quartz glass plate.

Note that the present invention is not limited to the above embodiments. The above-mentioned embodiments are merely illustrative, and any embodiment that has substantially the same configuration as the technical idea stated in the claims of the present invention and has similar effects is the present invention. within the technical scope of the invention.

10... Molded plate, 12... Molded plate main body, 14... Edge plate, 16... Additional plate,
20...mold,
30... Raw material powder supply means,
42...Raw material powder, 44...Raw material powder molded body, 46...Groove,
50...Quartz glass crucible manufacturing device.

Claims (15)

It comprises a rotatable mold and a raw material powder supply means for supplying raw material powder to the mold, and the raw material powder supplied by the raw material powder supply means to the inside of the mold is formed into a crucible-shaped raw material powder molded body. In an apparatus for manufacturing a quartz glass crucible by molding and melting the raw material powder molded body, a molding plate used for molding the raw material powder molded body,
The molding plate has a shape corresponding to the shape of the inner surface of the raw material powder molded body, and is disposed inside the mold so that the mold rotates relative to the molding plate. The raw material powder supplied into the mold is molded into the crucible shape,
The molded plate includes a molded plate main body and an edge plate that is detachable from the molded plate main body,
The edge plate has a shape corresponding to the shape of the surface at the upper end of the raw material powder molded body at a position facing the upper end of the raw material powder molded body when the molding plate is placed inside the mold. A molded plate characterized by having: 2. The molded plate according to claim 1, wherein the edge plate has a notch oblique to the thickness direction of the raw material powder molded body. 3. The molded plate according to claim 1, wherein at least a portion of the molded plate main body and the edge plate in contact with the raw material powder molded body is made of quartz glass. In addition to the edge plate, further includes an additional plate that is detachable from the molded plate main body,
The molded plate according to any one of claims 1 to 3, wherein the additional plate is capable of changing the shape of the inner surface of the raw material powder molded body. The molding plate according to claim 4, wherein when the molding plate is placed inside the mold, the additional plate is located in a crucible-shaped straight body portion of the raw material powder molded body. . The mold;
The raw material powder supply means;
A quartz glass crucible manufacturing apparatus comprising: the molded plate according to any one of claims 1 to 5; Claim characterized in that the shape at the upper end of the raw material powder molded body can be changed by replacing the edge plate or by changing the attachment position of the edge plate. 6. The quartz glass crucible manufacturing apparatus according to 6. By changing the shape of the upper end of the raw material powder molded body by replacing the edge plate or changing the attachment position of the edge plate, the height of the quartz glass crucible manufactured by melting the raw material powder molded body can be increased. 8. The quartz glass crucible manufacturing apparatus according to claim 7, wherein the quartz glass crucible manufacturing apparatus is capable of being changed. In addition to supplying raw material powder to the inside of a rotatable mold, a molding plate is arranged inside the mold, and the mold rotates relative to the molding plate, thereby transferring the raw material powder to the molding plate. a step of molding the raw material powder into a crucible-shaped raw material powder molded body corresponding to the shape of the mold;
and a step of melting the raw material powder molded body, in a method for manufacturing a quartz glass crucible,
The molding plate has a shape corresponding to the shape of the surface at the upper end of the raw material powder molding at a position facing the upper end of the raw material powder molding when the molding plate is placed inside the mold. 1. A method for manufacturing a quartz glass crucible, comprising molding a raw material powder molded body using an edge plate having an edge plate installed on a molding plate body. 10. The method for manufacturing a quartz glass crucible according to claim 9, wherein the edge plate has a notch oblique to the thickness direction of the raw material powder molded body. 11. The method for manufacturing a quartz glass crucible according to claim 9 or 10, wherein at least a portion of the molded plate main body and the edge plate in contact with the raw material powder molded body is made of quartz glass. In addition to the edge plate, an additional plate is further installed on the molded plate,
The method for manufacturing a quartz glass crucible according to any one of claims 9 to 11, characterized in that the shape of the inner surface of the raw material powder molded body is changed by the additional plate. The method for manufacturing a quartz glass crucible according to claim 12, characterized in that, when the molding plate is placed inside the mold, the additional plate is located in a crucible-shaped straight body portion of the raw material powder molded body. . Any one of claims 9 to 13, characterized in that the shape at the upper end of the raw material powder molded body is changed by replacing the edge plate or by changing the attachment position of the edge plate. The method for manufacturing a quartz glass crucible according to item 1. By changing the shape of the upper end of the raw material powder molded body by replacing the edge plate or changing the attachment position of the edge plate, the height of the quartz glass crucible manufactured by melting the raw material powder molded body can be increased. 15. The method for manufacturing a quartz glass crucible according to claim 14.

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