JP2011156569A - Method for producing gypsum mold, gypsum mold, and method for producing precision parts by the gypsum mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, in a cast product according to a gypsum casting method, by the slight shift in the fitting of the gypsum mold and a difference in the height of feeder heads upon casting, variation occurs in the machining origins to form into post-machining to cause variation in the product dimensions. <P>SOLUTION: A working margin is further added to a master model to which a shrinkage is imparted to product dimensions, and a gypsum mold 3 is prepared based on a master model 1 in which working standard members 15a to 15d with a cooling promotion action into the working margin. In the case a cast product 4 is produced using the gypsum mold, the working standard members are made into points and points grasping the shrunk conditions of the casting after the casting so as to be a series of working standards, and the product with a dense structure is produced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gypsum mold manufacturing method used for manufacturing precision parts by a gypsum casting method, a gypsum mold and a gypsum mold manufactured by a gypsum mold manufacturing method, and manufacturing a precision part using a gypsum mold. It is about the method.

Conventionally, the gypsum casting method has a problem that the gypsum mold used for casting is easily damaged. In order to improve this point, a reinforcing member formed by knitting a linear material in a predetermined shape is arranged in a portion where the loss of the rubber-type gypsum is likely to occur. A method has been proposed. (For example, see Patent Document 1)
This method suppresses the loss of the gypsum mold when the gypsum mold is released from the rubber mold into which the gypsum is poured, and the loss of the gypsum mold when producing a cast product such as a precision part using the gypsum mold. It becomes possible to suppress cracking.

In addition, since the gypsum casting method requires the same number of gypsum molds as the product, the shape and dimensions of the product depend on its individuality, such as the mold assembly state, and the casting filling density is improved during the casting. For this reason, there is a problem that nests, shrinkage, etc. (casting defects) occur in the casting depending on the height of the molten metal used for the purpose, and the quality is difficult to stabilize. In this regard, it has been proposed to apply a suction casting method to the manufacture of impellers as a method of manufacturing structural members with high quality and high reliability that prevent the occurrence of casting defects. (For example, see Patent Document 2)
In this suction casting method, a cavity having a space shape corresponding to the shape of an impeller is defined by a plaster member having air permeability and a cooling metal, and a plaster mold having a gate portion at a position facing the cooling metal The outer periphery of the part defining the impeller-shaped blade part of the mold is introduced into a chamber where the decompression space becomes a decompression space, the decompression space is decompressed, the cavity is decompressed via the plaster mold, and the molten metal is sucked from the sprue part. And cast into a cavity.

JP 2007-275923 A JP 2008-264846 A

  However, although the tolerance satisfied by the gypsum casting method can reach that of the die casting method, unlike the die casting method, the gypsum mold depends on the individuality of each product, so many products with dimensional tolerances on the order of tens of microns are manufactured. In this case, it is necessary to set a stable point in the product without depending on the shrinking direction in order to easily specify the machining origin. In this respect, the cast using a gypsum mold has a problem that it is difficult to obtain a processing origin and it is difficult to stably manufacture a product with strict dimensional accuracy.

  The gypsum casting method requires one master model and the same number of gypsum molds as the product from one master model because of its construction method. Therefore, in the molded product of the structural part by the plaster mold, due to the slight misalignment of the plaster mold and the difference in the height of the feeder during casting, the machining origin of the post-processing will vary, resulting in product dimensions. There was a problem of variation.

Furthermore, the gypsum material used for gypsum casting has a problem that hardness is not secured when the thickness is small, and it cannot be applied without machining to manufacture a structural part having a precise and complicated internal shape. It was.

  The present invention has been made to solve the above-described problems. By embedding a member in a gypsum mold for the purpose of setting a processing reference point in a cast itself manufactured by a gypsum casting method, It is an object of the present invention to provide a method for manufacturing a gypsum mold that makes it easy to set the processing origin during processing.

  In addition, the present invention produces a casting using a gypsum mold embedded with a member serving as a processing standard, and performs machining based on the individuality of the product based on the processing origin formed on the casting itself. It is an object of the present invention to provide a method for producing a precision part using a gypsum mold capable of producing a precision part product with excellent dimensional accuracy.

  The method for producing a gypsum mold of the present invention is a process for producing a master model in a size obtained by adding a shrinkage rate and a machining allowance of a casting material to a cast product as a final product, and setting the master model in a box with an outer frame. Pour the silicone resin into the box to cure the silicone resin, cut the cured silicone resin to create multiple rubber molds corresponding to the shape of the master model, cast the gypsum into the rubber mold and cure In any step from the step of producing a gypsum mold having a cavity according to the shape of the master model by releasing the cured gypsum from the rubber mold, the step of producing the master model to the step of producing the gypsum mold, It is provided with a step of providing a plurality of members that serve as processing standards for setting the machining origin according to the cast product at a location corresponding to the machining allowance.

  The gypsum mold of the present invention is a gypsum mold used in a gypsum casting method in which a molten metal is enclosed in a gypsum mold to produce a cast product, and the gypsum mold is larger in size than the final cast product. It is characterized in that a plurality of members are provided as processing standards for setting the machining origin of the cast product at a location corresponding to the processing cost of the gypsum mold.

  Furthermore, the manufacturing method of the precision part by the gypsum mold of the present invention includes a process for producing a cast product by enclosing a molten metal for casting from a gypsum mold gate, a process for taking out the cast product from the gypsum mold, and a processing standard for the cast product. And a step of machining the cast product based on the points formed by the members.

  In the gypsum mold manufactured by the manufacturing method of the present invention, the member that is the processing standard of the cast product inserted into the gypsum mold is a series of processing standards that make a point of grasping the contraction state of the cast product after casting. Thus, it becomes possible to manufacture a precise part by machining based on this.

  In addition, only parts where the plaster is thin and prone to breakage are replaced with gypsum, and members that satisfy dimensional accuracy and are not integrated with the molten metal are inserted in advance. This makes it possible to manufacture more precise parts.

  Also, a part of the gypsum mold is composed of a metal member having the same or lower melting point compared to the molten metal for casting, and the vicinity of the interface between the molten metal poured into the casting metal and the molten metal injected or in a wide range. It is possible to manufacture precision products that satisfy the required accuracy by forming a melted and fused shape and integrating it with the molten metal for casting, so that parts that have a precision structure remain in advance. It becomes possible.

The figure which shows the processing flow of the manufacturing method of the gypsum mold in Embodiment 1 of this invention, and the manufacturing method of precision components. The figure which shows the creation state of the master model of 1 process of the manufacturing method in Embodiment 1 of this invention. The figure which inserted the process reference member in the master model in Embodiment 1 of this invention. The figure which shows the creation state of the primary rubber type | mold of 1 process of the manufacturing method in Embodiment 1 of this invention. The perspective view which shows the primary rubber mold | type in Embodiment 1 of this invention. The figure which shows the creation state of the secondary rubber type | mold of 1 process of the manufacturing method in Embodiment 1 of this invention. The figure which shows the manufacture state of the gypsum mold of 1 process of the manufacturing method in Embodiment 1 of this invention. The assembly drawing of the gypsum mold in Embodiment 1 of this invention. The figure which shows the manufacture state of the cast product of 1 process of the manufacturing method in Embodiment 1 of this invention. The figure which shows the cast product in Embodiment 1 of this invention. The figure which shows an example of the machining state of the casting product of one process of the manufacturing method in Embodiment 1 of this invention. The figure which shows the other example of the machining state of the casting product of 1 process of the manufacturing method in Embodiment 1 of this invention. The figure which shows the processing flow of the manufacturing method of the gypsum mold in Embodiment 2 of this invention, and the manufacturing method of precision components. The figure which shows the creation state of the master model of the manufacturing method in Embodiment 3 of this invention. The figure which shows the example of the gypsum mold of 1 process of the manufacturing method in Embodiment 3 of this invention. The figure which shows the creation state of the master model of 1 process of the manufacturing method in Embodiment 3 of this invention. The figure which shows the manufacture state of the casting product of 1 process of the manufacturing method in Embodiment 3 of this invention. The figure which shows the creation state of the master model of 1 process of the manufacturing method in Embodiment 4 of this invention. The figure which shows the manufacture state of the casting product of 1 process of the manufacturing method in Embodiment 4 of this invention. It is a perspective view of the gypsum mold in Embodiment 5 of this invention.

Embodiment 1 FIG.
Hereinafter, the manufacturing method of the gypsum mold in Embodiment 1 of this invention, and the manufacturing method of the precision component by the gypsum mold which manufactures a precision component using the gypsum mold manufactured by the manufacturing method of a gypsum mold are shown in FIGS. 12 will be described.
In the following description, an aluminum horn antenna is described as a precision part, but the present invention is not limited to this.

The overall flow of the gypsum mold manufacturing method and the precision component manufacturing method using the gypsum mold according to Embodiment 1 of the present invention is performed based on the processing flow shown in FIG.
In FIG. 1, first, step S1 is a process of manufacturing a master model by cutting ABS resin or the like based on a manufacturing drawing of precision parts. This step S1 consists of two steps S11 and S12. In step S11, the master model adjusts the shrinkage rate of the casting material (for example, aluminum) and the machining of the casting to the size of the precision part as the final product. Produced in a size that adds the machining allowance. The shrinkage ratio of the casting material varies depending on the casting material and the shape and size of the product, but approximately 1/100 ± 2/1000 is added.
In step S12, a member serving as a machining reference for setting a machining origin corresponding to the cast product is provided at a location corresponding to the machining allowance of the master model manufactured in step S11. The insertion position of the member serving as the processing standard is set to a portion where the thickness of the plaster is sufficiently large because there is a risk of damaging the mold portion where the thickness of the plaster is thin.

FIG. 2 shows a diagram of the master model manufactured in step S11. FIG. 2 (a) is a front view, FIG. 2 (b) is a side view, FIG. 2 (c) is a top view, and FIG. A perspective view is shown.
The master model 1 shows an example of a horn antenna. The horn antenna includes a trumpet-shaped horn portion 11 and a power feeding portion 12. In addition, the master model 1 has a size obtained by adding machining allowances 13a and 13b for machining a portion where a dimensional tolerance of the precision component is required and a shrinkage rate of the casting material to the size of the precision component as the final product. It is made with. Furthermore, holes 14a to 14d for embedding the members serving as the machining reference provided in step S12 are provided at locations corresponding to the machining allowances 13a and 13.

FIG. 3 shows a view of the master model 1 provided with members (hereinafter referred to as reference bars) 15a to 15d, which are processing standards manufactured in step S12. FIG. 3 (a) is a front view, and FIG. ) Is a side view, and FIG. 3C is a top view.
The reference rods 15a to 15d are inserted into the holes 14a to 14d and embedded therein, and when the reference rods 15a to 15d are expected to serve as a cooling metal during casting, a copper alloy having a melting point higher than that of the cast metal, steel, It is composed of SUS or the like. In the case where the reference rods 15a to 15d are not expected to serve as a cooling metal and the structure is prioritized, it is possible to use a non-metallic material such as a ceramic which is heat resistant and hardly distorts. Further, the shape of the rod is a square rod, but a cylindrical rod may be used. In addition, the number is shown as four in the figure, but depending on the product, a large number such as six to ten is provided.

The reference rods 15a to 15d are necessary when casting a cast product using a gypsum mold manufactured in a later process, and finally need to be provided in the gypsum mold. May be. Therefore, the reference rods 15a to 15d have a shape that is less likely to be fused and integrated with the rubber mold and the cast material for producing the gypsum mold, have a high strength, and are easily pulled out from the holes 14a to 14d. If the reference rods 15a to 15d have a shape that is weak and difficult to pull out, the releasability is ensured by a release agent or the like.
Further, the positions where the reference rods 15a to 15d are provided are set so as to have a machining allowance with a sufficient gypsum thickness because there is a risk of damaging a mold portion having a thin strain gypsum thickness at a high temperature.

  Next, step S2 in FIG. 1 is a process of creating a silicon mold (rubber mold) for producing a gypsum mold based on the master model 1. This step S2 includes three steps S21, S22, and S23. In step S21, a primary mold of a silicon mold (rubber mold) is created. As shown in FIG. 4, the primary model is created by fixing the master model 1 having the reference rods 15 a to 15 d in a box 21 with an outer frame, and flowing a liquid silicon resin into the box 21. Harden.

  In step S22, after the silicon is cured, the reference rods 15a to 15d are extracted and removed, and the silicon resin is cut and divided along a parting line 22 (shown by a solid line) with a cutter as shown in FIG. As shown in FIG. 5, the master model 1 is taken out from the divided and divided silicon resin, and primary molds 2a to 2d of a silicon mold (rubber mold) divided into four are created. The primary molds 2a to 2d of the rubber mold have holes after extracting the reference rods 15a to 15d, respectively.

  In step S23, as shown in FIG. 6, the silicon mold (rubber mold) secondary mold 2aa to the primary mold 2a to 2d transferred from the quadrant silicon mold (rubber mold) primary mold 2a to 2d. This is a process of creating 2dd. The secondary mold is created by inserting the reference rods 15a to 15d again into the holes of the primary molds 2a to 2d of the silicon mold (rubber mold) and placing the silicon mold (rubber mold) in the box 23 with the outer frame assembled. ) Primary molds 2a to 2d are fixed, and a liquid silicon resin is poured into the box 23 and hardened to produce silicon (rubber mold) secondary molds 2aa to 2dd.

  Next, step S3 in FIG. 1 is a process for manufacturing a gypsum mold from the silicon mold (rubber mold) secondary molds 2aa to 2dd. This step S3 consists of two steps S31 and S32. In step S31, as shown in FIG. 7, each of the silicon type (rubber type) secondary molds 2aa to 2dd having the reference rods 15a to 15d is provided. Liquid gypsum is allowed to flow into and hardened, and the cured gypsum is released from the rubber-type secondary molds 2aa to 2dd to produce gypsum molds 3a to 3d (reference numeral 3 in the collective name). The gypsum molds 3a to 3d have the same shape as the silicon mold (rubber mold) primary molds 2a to 2d shown in FIG. 5, but the gypsum molds 3a to 3d are provided with reference bars 15a to 15d. When manufacturing the gypsum molds 3a to 3d, a column hole 31 is inserted to add a hole for a gate that encloses a casting material. Further, the gypsum mold 3 is manufactured from the rubber-type secondary molds 2aa to 2dd for the required number of cast products, and quenched to completely remove moisture.

In step S <b> 32, as shown in FIG. 8, the gypsum molds 3 a to 3 d divided into four are assembled into a gypsum mold 3 having a cavity 31 having the same shape as the master model 1. The gypsum mold 3 is also provided with a gate 32 for enclosing a casting material.
8 (a) is a front view, FIG. 8 (b) is a side view, and FIG. 8 (c) is a top view. In order to make the structure easy to understand, some gypsum molds 3a to 3d are shown. The illustration is omitted.
The reference bars 15a to 15d are fixed to each other by a plate material 33 of the same type as the member or more stable against heat, which is provided outside the gypsum mold 3 in order to maintain the positional relationship of the reference members (reference bars). ing. Needless to say, holes for penetrating the reference rods 15a to 15d are formed in the plate member 33 in advance.

Next, step S4 in FIG. 1 is a process for manufacturing a cast product which is a precision part from the gypsum mold 3. In this step S4, as shown in the side view of FIG. 9A and the top view of FIG. The cavity 31 is filled and cured. At this time, since the reference rods 15a to 15d serving as a processing reference that also serves as cooling metal are inserted into the processing allowance giving portion, cooling of the cast metal is promoted, and the contraction direction and parallel between the reference rods 15 are parallel.・ It is possible to define the vertical direction and set the machining origin.
Note that any method of injecting the molten metal may be used, and a suction casting method may be used. After the casting material is cured, the plate material 33 is removed, the gypsum mold 3 is crushed and removed, and the cast product 4 is manufactured by washing.

Next, step S5 in FIG. 1 is a process of manufacturing a precision product by machining the cast product 4 on the basis of the points formed on the cast product 4 by the reference rods 15a to 15d serving as processing standards.
FIG. 10 shows the cast product 4 manufactured in step S5, FIG. 10 (a) is a front view of the cast product 4, and FIG. 10 (b) is a side view. FIG. 10 shows a state in which reference bars 15a to 15d (15 in general terms) serving as a processing reference are still attached to the machining allowances 41a and 41b, but the reference bars 15a to 15d are pulled out in this state. Good. When the reference rods 15a to 15d are pulled out, the trace hole becomes the reference point.

There are various ways of machining the casting 4, and an example will be described with reference to FIGS. 10 to 11. First, as shown by the upper arrow in FIG. 10 (b), the positional relationship between a specific portion (place as a measurable reference) A inside the cast product 4 and the reference rods 15a and 15c is measured, and this distance is the original. The positional relationship set at the time of the master model 1 and the degree of deviation are measured. By clarifying this relationship, in addition to this example, if the part has an internal structure, it becomes clear how much the internal structure is contracted and in which method, and the shape balance of the cast product 4 becomes clear. .
Further, by measuring the positional relationship between the positions of the trace holes after removing the reference rod 15 used for confirming the positional relationship, it is possible to confirm whether the reference rod 15 itself is moving or not. And the presence or absence of shrinkage can be clarified.

After clarifying the contraction state of the casting product 4 in this way, as shown in FIG. 11A, the machining allowance 41b on the power feeding portion side of the horn antenna, which is a precision product, can be machined and measured. The distance from the reference location A to the end of the power feeding unit is made accurate.
Next, as shown in FIG. 11B, the machining margin 41a on the horn portion side of the horn antenna is machined so that the distance from the feeding portion end to the horn end after machining is accurate.

  Another example of machining will be described with reference to FIGS. First, as indicated by the arrow on the lower side of FIG. 10B, the reference bar 15 serving as a processing reference is fixed. Therefore, the reference bar 15c is set as the initial processing position (origin), and then FIG. As shown in a), the machining allowance 41b on the feeding portion side of the horn antenna, which is a precision product, is machined. Next, as shown in FIG. 12B, the machining allowance 41a on the horn part side of the horn antenna is machined so that the distance from the feeding part end to the horn part end becomes accurate.

  As described above, according to the first embodiment, the gypsum mold for casting a precision product is provided with a machining allowance at a location where a dimensional tolerance of the precision product is required, and a machining origin is set at a location corresponding to the machining allowance. By inserting a processing reference member for the purpose, it is possible to manufacture a precise part by forming a series of processing standards by making a point with respect to the contraction state of the cast product.

Embodiment 2. FIG.
Next, FIG. 13 shows a method for manufacturing a precision part using a gypsum mold that manufactures a precision part using the gypsum mold manufactured by the method for manufacturing a gypsum mold and the method for manufacturing a gypsum mold according to Embodiment 2 of the present invention. This will be explained based on this.
In the method for manufacturing a gypsum mold in the first embodiment, the member (reference bar) 15 serving as a processing reference for setting the machining origin according to the cast product is provided from the stage of manufacturing the master model 1. The invention of Form 2 is provided for the first time in the production stage of the gypsum mold.

The entire flow of the gypsum mold manufacturing method and the precision component manufacturing method using the gypsum mold according to the second embodiment of the present invention is performed based on the processing flow shown in FIG.
In FIG. 13, first, step S10 is a process of manufacturing a master model by cutting ABS resin or the like based on a manufacturing drawing of precision parts. In this case, the master model can be made into a cast product simply by adding the size of the precision part, which is the final product, to the size of the casting material (for example, aluminum) and the machining allowance for machining the cast. A member (reference bar) 15 serving as a processing reference for setting a corresponding machining origin is not provided.

Next, step S20 in FIG. 13 is a step of creating a silicon mold (rubber mold) for producing a gypsum mold based on the master model 1. This step S20 comprises the same three steps S21, S22, and S23 as in the first embodiment, except that there is no member (reference bar) 15 that is a machining reference for setting the machining origin according to the cast product. . Accordingly, the steps S21, S22, and S23 are the same as those in the first embodiment, and the description thereof is omitted.

Next, step S30 in FIG. 13 is a process for producing a gypsum mold from a silicon mold (rubber mold) secondary mold. This step S30 is composed of two steps S33 and S34. In step S33, a machining origin corresponding to the cast product is set at a position corresponding to the machining allowance of the secondary mold of the silicon mold (rubber mold). A gypsum mold 3 is manufactured by providing a member (reference bar) 15 serving as a processing standard.
The process of realizing the processing standard member (reference bar) 15 corresponds to each stage of the process of manufacturing the gypsum mold, the stage of pouring gypsum into the secondary mold of the rubber mold, the stage of semi-curing or curing the gypsum, There are four stages: a stage after complete curing of gypsum and before drying and a stage after drying and curing.
In short, the member serving as the processing standard may be embedded at any time of the process from the pouring of gypsum into the rubber mold to the post-drying and before casting in the process of manufacturing the gypsum mold 3.

In step S34, the divided gypsum mold is assembled into the gypsum mold 3 having the cavity 31 having the same shape as the master model 1, and is the same as in the first embodiment.
Next, step S40 in FIG. 13 is a process for producing a cast product 4 which is a precision part from the gypsum mold 3, and step S50 is based on a point formed on the cast product 4 by a reference bar which is a processing standard. In this process, the casting product 4 is machined to produce a precision product. These steps are also the same as those in the first embodiment, and a description thereof will be omitted.

As described above, the invention of the second embodiment is similar to that of the first embodiment by inserting the processing reference member for setting the machining origin during the manufacturing process of the gypsum mold for casting the precision product. It is possible to manufacture precise parts by making a series of processing standards by making the point of grasping the contraction state of the product.
In addition, as the step of inserting the machining reference member for setting the machining origin, the step of producing the master model 1 in the first embodiment and the step of producing the gypsum mold 3 in the second embodiment have been described. You may insert in the step which produces a silicon type | mold (rubber type | mold). In short, the methodologies in the embodiments may employ any one of the above steps, or may use a combination of several steps.

Embodiment 3 FIG.
Next, a method for manufacturing a precision part using a gypsum mold that manufactures a precision part using the gypsum mold manufactured by the method for manufacturing a gypsum mold and the method for manufacturing a gypsum mold according to Embodiment 3 of the present invention will be described with reference to FIGS. This will be described with reference to FIG.
In the first embodiment, the basic method for manufacturing an aluminum horn antenna as a precision component has been described. However, in an actual product, a member for adjusting electrical characteristics is often provided inside the horn portion of the horn antenna. . The invention of the third embodiment will explain a method for manufacturing such a precision part.

The overall flow of the gypsum mold manufacturing method and the precision part manufacturing method using the gypsum mold according to Embodiment 3 of the present invention may be either the processing flow shown in FIG. 1 or the processing flow shown in FIG.
First, a master model is manufactured by cutting ABS resin or the like based on a manufacturing drawing of precision parts. In this case, the master model is manufactured in a size obtained by adding the shrinkage rate of the casting material (for example, aluminum) and the machining allowance for machining the casting to the size of the precision part as the final product.

  FIG. 14 shows a diagram of the master model, FIG. 14 (a) is a side view, FIG. 14 (b) is a top view, FIG. 14 (c) is a front view, and FIG. 14 (d) is a front perspective view. Represents. The master model 1 includes a trumpet-shaped horn portion 11 and a power feeding portion 12, and a new moon-shaped projection portion 13 that is an adjustment portion for electric characteristics is provided inside the horn portion 11 so as to be opposed thereto. The protruding portion 13 faces the feeding portion 12 side with a narrow dimension such that the interval is about 0.6 mm. Further, the master model 1 is manufactured in a size in which machining allowances 13a and 13b for machining are added to a portion where a dimensional tolerance of a precision part is required.

  When a silicon mold (rubber mold) for producing a gypsum mold is created based on the master model 1 shown in FIG. 14, and then a gypsum mold is fabricated from the silicon mold (rubber mold), the gypsum mold 3 is shown in FIG. The gypsum molds 3a to 3d divided into four as shown in FIG. In the gypsum molds 3a to 3c, there is no particular problem, but in the gypsum mold 3d, the portion 34 corresponding to the opposing portion of the protrusion 13 has a thin gypsum thickness and cannot maintain strength. Defects are likely to occur.

Therefore, the invention of the third embodiment is changed from the manufacturing stage of the master model 1 to a portion where the thickness of the gypsum becomes thin and the strength cannot be maintained as shown in FIG. The member 35 for reproducing the part is inserted, and the subsequent steps are manufactured in the same manner as in the first embodiment, and the gypsum mold 3 in which the member 35 for reproducing the precise part is integrally formed is manufactured. The member 35 that satisfies this dimensional accuracy is preferably a member that is not integrated with the molten metal and that also serves as a cooling metal.
Further, the shape of the member 35 satisfying the dimensional accuracy may be a plate material or formed along the internal shape, and the length may be cut off at a part of the gypsum mold or across the end face. Good.

FIG. 17 is an assembly view of the gypsum mold 3 in the invention of Embodiment 3, FIG. 17 (a) is a front view, FIG. 17 (b) is a side view, and FIG. 17 (c) is a top view. For ease of illustration, some of the gypsum molds 3a to 3d are omitted.
The process of manufacturing a cast product using such a gypsum mold 3 and the process of machining the cast product are the same as in the first embodiment.
The member 35 that satisfies the dimensional accuracy is provided by being inserted in advance in a portion corresponding to a portion where the protruding portion 13 that is an adjustment portion of the electrical property faces, that is, a portion that is likely to be damaged when originally manufactured with gypsum. . Therefore, the member 35 that satisfies the dimensional accuracy serves to form a shape by substituting the thin and thin portion of the gypsum mold 3, and the fine gypsum that is easily distorted when flowing the molten metal into the gypsum mold 3. It also serves to reinforce the part and prevent distortion. Further, since the cast product at this location is manufactured with high accuracy, the number of machining locations can be reduced, and parts with a precise structure can be manufactured.

Embodiment 4 FIG.
Next, a method for manufacturing a precision part using a gypsum mold in which a precision part is manufactured using the gypsum mold manufactured by the method for manufacturing a gypsum mold and the method for manufacturing a gypsum mold according to Embodiment 4 of the present invention will be described with reference to FIGS. This will be described with reference to FIG.
In the invention of the fourth embodiment, the shape of the member 35 that satisfies the dimensional accuracy used in the invention of the third embodiment is changed.

  18 shows a diagram of the master model 1 corresponding to FIG. 16, where FIG. 18 (a) is a front view, FIG. 18 (b) is a side view, and FIG. 18 (c) is a top view. The master model 1 includes a trumpet-shaped horn portion 11 and a power feeding portion 12, and a square-shaped protruding portion 13 serving as an adjustment portion for electric characteristics is provided inside the horn portion 11 so as to be opposed to the master model 1. In the third embodiment, the new moon-shaped protrusion 13 is shown, but the shape of the protrusion 13 is not particularly limited. The master model 1 is manufactured in such a size that a machining allowance for machining is added to a portion where a dimensional tolerance of a precision part is required.

  As shown in FIG. 18, from the production stage of the master model 1, the thickness of the gypsum becomes thin and the strength cannot be maintained, and the shape along the internal shape of the projection 13 of the horn portion satisfies the dimensional accuracy in advance. And a member 36 for reproducing a precise part is inserted, and can be integrally formed with the gypsum mold 3. The member 36 that satisfies this dimensional accuracy is preferably a member that is not integrated with the molten metal and that also serves as a cooling metal.

19 is an assembly view of the gypsum mold 3 in the invention of Embodiment 4, FIG. 19 (a) is a front view, FIG. 19 (b) is a side view, and FIG. 19 (c) is a top view. For ease of illustration, some of the gypsum molds 3a to 3d are omitted.
The member 36 that satisfies the dimensional accuracy is provided along the internal shape of the protrusion 13 serving as an adjustment portion for electrical characteristics. As described above, the member 36 serves to form a shape by replacing the thin and thin portion of the gypsum mold 3 and reinforces the fine portion of the gypsum that is easily distorted when flowing the molten metal into the gypsum mold 3. It also has the role of preventing distortion.

  As in the fourth embodiment, not only as a machining origin but also a member 36 satisfying dimensional accuracy can be installed only in a structurally important part, and the shape can be stably formed. As a result, the portion where the member 36 is buried as a cooling metal has an interface with the casting metal, so that the cooling of the casting metal is promoted to reduce the size of the metal grains, and the gypsum mold 3 is manufactured as a single unit. Compared to the case, the strength of the crystallized metal is increased.

Embodiment 5 FIG.
Next, FIG. 20 shows a method for manufacturing a precision part using a gypsum mold that manufactures a precision part using the gypsum mold manufactured by the method for manufacturing a gypsum mold and the method for manufacturing a gypsum mold according to Embodiment 5 of the present invention. This will be explained based on this.
In the inventions of the third and fourth embodiments, the members 35 and 36 that satisfy the dimensional accuracy are inserted in place of the thin and thin portions of the gypsum mold 3, but the invention of the fifth embodiment is a part of the gypsum mold. In particular, the thin and thin portion of the gypsum mold 3 is constructed by attaching a metal having a melting point equal to or lower than that of the molten metal for casting, and integrated with the molten metal for casting. .

  FIG. 20 shows a perspective view of the gypsum mold 3. First, when creating a primary rubber mold from the master model 1, a member (internal structure reproduction member) corresponding to the protrusion 13 serving as an electric characteristic adjusting portion provided inside the horn portion 11 of the horn antenna is used as a molten metal for casting. It is composed of a metal 37 having the same or lower melting point than that of metal, and is fixed to the master model 1 and molded. Next, when the gypsum mold is manufactured from the secondary rubber mold to which the primary rubber mold is transferred, a groove into which the internal structure reproducing member is inserted is formed in the gypsum mold. Next, a metal 37 having a low melting point is inserted into the groove to produce a gypsum mold, and molten metal is injected from the gypsum mold gate to produce a cast product. Due to the molten metal injected from the gypsum mold mouth during this casting, the metal 37 having a low melting point is melted, and the vicinity of the interface with the injected molten metal or a wide area is melted and fused to form a molten metal for casting. As a result of the integration, a part that has been processed in advance remains in a part having a precision structure, and a precision product that satisfies the required accuracy can be manufactured.

In the invention of the fifth embodiment, only a part having a severe product dimension is manufactured in advance by machining with a metal, and is structured by being integrated with a cast metal. When embedding the metal 37 in this way, a difference is made in whether or not the cast metal and the metal 37 are integrated as components.
If the metal to be buried has the same or higher melting point than the metal for casting, it will not be joined and integrated by melting. In addition, it is necessary to prevent decomposition and peeling between these metals.

  If the metal to be buried has a low melting point compared to the metal for casting, it is possible to join and integrate by melting, so do not make a hook structure etc. on the buried member side and use it with the product Is possible. However, also in this case, it is necessary to make a hooking structure or the like on the member side to be buried so that there is no decomposition / peeling between these metals. Further, the cast metal is cooled at the time of casting, and heat is taken away at the time of contact with the member. For this reason, since the case where the said member cannot be melt | dissolved enough even if it is a low melting point is considered, it is desirable to employ | adopt an uneven structure so that a contact surface may become large. At this time, it is important to take care not to disturb the flow of the molten metal.

  Parts obtained by the manufacturing method of the present invention can reduce the individuality of castings as much as possible, and even for those with strict dimensional accuracy, the processing origin can be clearly determined according to the individuality of the product, and precision parts can be manufactured by machining. It becomes possible. This makes it possible to apply gypsum casting even to electrical parts and the like that require dimensional accuracy and parts that do not vary in individuality. In addition, since the precision part can be formed by a member charged in advance, the number of processing steps can be reduced and the part can be reproduced more faithfully even if the dimensional accuracy of the part is severe.

1: Master model 2a-2d: Rubber mold primary mold 2aa-2dd: Rubber mold secondary mold 3, 3a-3d: Plaster mold 4: Cast product 11: Master model horn part 12: Master model power supply part 13a , 13b: Processing cost of the master model 14a-14d: Hole 15, 15a-15d: Processing reference member (reference bar)
16: Protrusions for adjusting the electrical characteristics of the master model 21: Box for creating a primary rubber mold 22: Parting line (cut surface)
23: Box for creating secondary rubber mold 31: Cylindrical part for creating gate 32: Cup gate 33: Fixing bracket 34: Cavity 35: Member satisfying dimensional accuracy 36: Member satisfying dimensional accuracy 37: Member for reproducing internal structure ( Metal with low melting point)
41a, 41b: Processing cost of casting products

Claims (14)

  A process for producing a master model in a size obtained by adding the shrinkage rate of the casting material and the machining allowance to the cast product which is the final product, setting the master model in a box with an outer frame, and silicon resin in the box The step of creating a plurality of rubber molds corresponding to the shape of the master model by cutting the cured silicone resin, curing the silicone resin, pouring gypsum into the rubber mold and curing the cured gypsum In one of the steps of producing a gypsum mold having a cavity corresponding to the shape of the master model by releasing from the rubber mold, from the step of producing the master model to the step of producing the gypsum mold, A step of providing a plurality of members serving as processing standards for setting a machining origin according to a cast product at a location corresponding to the machining allowance. Method for producing a plaster mold.   2. The method for manufacturing a gypsum mold according to claim 1, wherein the member serving as the processing standard is provided during a process of manufacturing the master model.   2. The method for manufacturing a gypsum mold according to claim 1, wherein the member serving as the processing standard is provided during the step of creating the rubber mold.   2. The method for producing a gypsum mold according to claim 1, wherein the member serving as a processing standard is any one of the steps from pouring the gypsum into a rubber mold to dry casting and before casting in the step of producing the gypsum mold. A method for producing a gypsum mold, which is provided during the process.   5. The gypsum mold manufacturing method according to claim 1, wherein the member serving as the processing standard is a member that is higher than the melting point of the molten metal for casting and that is not integrated with the molten metal. A method for manufacturing a plaster mold.   6. The method for producing a gypsum mold according to claim 5, wherein the member serving as the processing standard uses a metal rod that functions as a cooling metal that promotes cooling of the molten metal for casting.   6. The method of manufacturing a gypsum mold according to claim 5, wherein the member serving as the processing standard is a non-metallic material that is heat resistant and hardly distorted.   8. The method for manufacturing a gypsum mold according to claim 1, wherein only a portion where the gypsum is thin and easily breaks is replaced with gypsum, satisfying dimensional accuracy and not integrated with the molten metal. A method for producing a gypsum mold in which a gypsum mold is formed.   5. The method for producing a gypsum mold according to claim 1, wherein a part of the gypsum mold is configured by attaching a metal having a melting point equal to or lower than that of a molten metal for casting. A method for manufacturing a gypsum mold that is integrated with a molten metal for casting.   In the gypsum mold used in the gypsum casting method in which the molten metal is enclosed in the gypsum mold to produce a cast product, the gypsum mold is created in a shape with a size that adds a processing allowance to the cast product that is the final product, A gypsum mold characterized in that a plurality of members serving as processing standards for setting a machining origin of the cast product are provided at a location corresponding to a machining allowance of the gypsum mold.   A step of producing a cast product by enclosing a molten metal for casting from a spout of a gypsum mold manufactured by the method for manufacturing a gypsum mold according to any one of claims 1 to 9, wherein the cast product is A method for producing a precision part using a gypsum mold, comprising a step of removing from a gypsum mold, and a step of machining the cast product based on a point formed on the cast product by a member serving as a processing reference.   12. The method for producing a precision product using a gypsum mold according to claim 11, wherein the member serving as the processing standard is removed from the member before being machined after casting.   12. The method for producing a precision product using a gypsum mold according to claim 11, wherein the member serving as a processing standard is a gypsum mold in which the member is buried in the cast product and machined after casting. Manufacturing method of precision parts.   The method for producing a precision product using a gypsum mold according to any one of claims 11 to 13, wherein a part of the gypsum mold is attached with a metal having the same or lower melting point than a molten metal for casting. A precision part manufacturing method using a gypsum mold that is constructed by joining and integrating with molten metal for casting by the heat of molten metal during casting.

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