JP5646247B2 - Casting product manufacturing method and mold - Google Patents

Description

The present invention relates to a mold to be applied when carrying out the manufacturing method and the manufacturing method of the Note form article using the thermosetting material.

  Epoxy resin castings are used as structural insulators installed in high-voltage substations such as gas-insulated switchgears because they have excellent electrical insulation and mechanical properties as solid insulators. Has been. In recent years, cast products made of epoxy resin have been required to be applied to higher-voltage power facilities and the like while ensuring long-term reliability as a solid insulator.

  As a method for producing an epoxy resin cast product, a pressure gelation method or the like is used. In the pressure gelation method, resin injection is started in a state where the inside of the mold is heated above the thermosetting temperature of the resin injected into the mold until filling of the resin into the mold cavity is completed. This is a production method in which the resin corresponding to the volume shrinkage at the time of resin curing is continuously supplied under pressure. By adopting such a pressure gelation method, it becomes possible to mass-produce cast products with high quality and high reliability in a short time (see, for example, Patent Document 1).

By the way, in a gas insulated switchgear having a specification with a rated voltage exceeding 500 kV, for example, many cast products having a total epoxy resin volume exceeding 7000 cc (cm ³ ) are used as insulating spacers. For cast products with large product sizes, the entire resin does not fully heat cure at the stage of primary curing in the mold cavity. It is cast over. Here, when the productivity of the insulating spacer is taken into account, since the production capacity is limited in a general casting method, casting by the pressure gelation method described above is desired.

JP 2005-53165 A

  However, the pressure gelation method has an advantage that a cast product having a relatively small product size can be produced in a short time, but it is difficult to apply to a cast product having a large epoxy resin volume exceeding 4000 cc, for example. It is said to be a thing. That is, when casting a cast product with a large product size by the pressure gelation method, while a large amount of resin injected into the mold cavity is gradually heat-cured from the outer periphery toward the center, In this heat curing process, it is necessary not to first heat cure (clog) the vicinity of the resin inlet in the mold. For this reason, temperature control that is extremely difficult with the current casting technique is required for the mold.

  Furthermore, the pressure gelation method is a manufacturing method in which a resin for making up for the volume shrinkage when the resin is cured is replenished while pressurizing the mold, but the outer peripheral portion of the resin in the mold is completely cured. Later, if the resin is excessively replenished and pressed too much, cracks may occur in the cast product, and a thin skin (double skin) may be formed from the replenished resin on the outer periphery of the cast product. is there.

  In addition, in order to produce a large-sized cast product made of epoxy resin, the cast product in the mold is used regardless of which of the general casting method and pressure gelation method is applied. The cast product is removed from the mold when the outer periphery of the mold has been cured to a certain level of hardness, and then the cast product is removed from the heating furnace in order to provide final physical properties such as high heat resistance. And then secondarily cured. However, the secondary curing in this case is realized by heating the cast product that has been taken out from its outer peripheral side, so that sufficient heat is transferred to the center of the cast product and the entire cast product is completely removed. For example, a curing time of as much as several tens of hours is required to cure.

The present invention has been made to solve the above problems, the thermosetting Note form article material with productivity can increase a note molded products manufacturing how and mold For the purpose of provision.

In order to achieve the above object, a method for producing a cast product according to an aspect of the present invention is characterized in that a thermosetting casting material is poured into a heated mold while being poured into the mold. When the outer peripheral portion of the molding material is thermally cured to obtain a semi-cured product, and when the thermosetting of the semi-cured material obtained in the mold while continuing the pressure supply proceeds to the center side The semi-cured product is internally heated from the center by reaction heat generated in the process, and the replenishment of the casting material is performed according to the occurrence of thermal expansion of the semi-cured product that has internally generated heat in the mold. A step of stopping, a step of supplementing the volume shrinkage at the time of curing by repeating thermal expansion from the center side of the semi-cured material in the mold after stopping the pressurizing supply, wherein from within the mold after a predetermined time elapses after the圧補supply is stopped Characterized by comprising the steps of: to eject the cured product, a step of thermally curing the entire semi-cured product comprising the central portion by continuing the internal heating the semi-cured product of a predetermined time allowed to taken out, the And

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the cast article which can improve the productivity of the cast article using a thermosetting material, a metal mold | die, and the gas insulated switchgear provided with this cast article are provided. be able to.

The figure which shows the structure of the gas insulated switchgear which concerns on embodiment of this invention. Sectional drawing which shows the structure of the connection bus line with which the gas insulated switchgear of FIG. 1 is provided. Sectional drawing which shows the structure of the post-shaped insulation spacer provided in the connection bus-line of FIG. Sectional drawing which shows the structure of the metal mold | die (in the state where the nest | insert and the embedding metal mold were set) used for manufacture of the insulation spacer of FIG. FIG. 5 is a detailed view of part A of the mold shown in FIG. 4. Sectional drawing which shows the structure of the other metal mold | die for comparing a structure with the metal mold | die shown in FIG. 4, FIG. FIG. 5 is a detailed view of part B of the mold shown in FIG. 4. The figure for demonstrating the function of the inclination part shown by the B section detailed drawing of FIG. The figure which shows the state at the time of setting a nest | insert or an embedded metal mold in the metal mold | die of FIG. Sectional drawing which shows the state by which the casting material was inject | poured in the metal mold | die in which the nest | insert and the embedded metal fitting of FIG. 9 were set. Sectional drawing which shows the state which the further thermosetting of the semi-hardened | cured material which the outer peripheral part heat-cured in the metal mold | die of FIG. 10 is progressing toward the center part. Sectional drawing which shows the state which the semi-hardened | cured material of FIG. 11A is self-expanding by internal heat_generation | fever. Sectional drawing which shows the state which took out the semi-hardened | cured material of the state of FIG. 11C is a cross-sectional view showing a state in which further thermosetting of the semi-cured product taken out from the mold of FIG. 11C is continuously progressing toward the central portion. FIG. FIG. 11D is a cross-sectional view illustrating a state where the entire semi-cured product of FIG. 11D is thermally cured to obtain a post-type insulating spacer.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
As shown in FIG. 1, a gas insulated switchgear (GIS: Gas Insulated Switchgear) 1 of this embodiment includes main busbars 12 and 14 and a bushing 21 and is filled with sulfur hexafluoride (SF ₆ ) gas. The open / close facility accommodates the disconnectors 15 and 16, the circuit breaker 17, the current transformer 18, the connection bus 19, and the like in the grounded container. For example, when breaking the current, the breaker 17 described above extinguishes the discharge by blowing the sulfur hexafluoride gas having high insulation between the arc-discharged electrodes of the switch.

  As shown in FIG. 2, the connection bus 19 is configured in such a manner that a high-voltage conductor 22 for energizing current is housed inside a connection container 20 having a ground potential. The high voltage conductor 22 is supported in the connection container 20 via the cone-shaped (conical) insulating spacers 23 and 24 and the post-shaped insulating spacer 3. The cone-shaped insulating spacers 23 and 24 support the high voltage conductor 22 while isolating the sulfur hexafluoride gas inside the connection container 20.

  Here, the structure of the post-shaped insulating spacer 3 will be described. As shown in FIGS. 2 and 3, the post-shaped insulating spacer 3 is formed by integrally molding a spacer main body 5 made of epoxy resin and a set of embedded fittings 7 and 8 which are metallic embedded members. It consists of cast products. The spacer main body 5 having electrical insulation is formed in a barrel shape in which a central portion of a cylinder is expanded.

  As shown in FIGS. 2 and 3, a set of embedded metal fixtures 7 and 8 is provided at each end of the spacer body 5. As shown in FIG. 2, one embedded metal 7 is mechanically connected to the high voltage conductor 22, and the other embedded metal 8 is mechanically connected to the inner portion of the connection container 20. Thus, the insulating spacer 3 supports the high voltage conductor 22 on the inner wall surface of the connection container 20 from the bottom side in a posture in which the axial direction of the insulating spacer 3 is raised.

  An epoxy resin, which is a thermosetting casting material, is applied to the material of the spacer body 5. More specifically, as this epoxy resin, an acid anhydride curing agent and alumina as an inorganic filler blended in a liquid bisphenol A epoxy resin are used. Instead of such an epoxy resin, a silicone resin containing a predetermined curing agent and filler can be applied as a thermosetting casting material for casting the spacer body 5. .

  Further, as shown in FIG. 3, the spacer body 5 is provided with a peripheral cover portion 9 having a thickness of 3 mm to 10 mm that covers the peripheral edges of the embedded metal objects 7 and 8. More specifically, the peripheral edge covering portion 9 is formed so as to cover the edges of the embedded metal objects 7 and 8 located at both ends of the insulating spacer 3. By virtue of this peripheral covering portion 9 being provided, it is possible to suppress the occurrence of burrs at the peripheral edges of the embedded metal pieces 7 and 8 after casting for reasons that will be described later.

  Further, as shown in FIG. 3, a plurality of steps are formed on the bulging peripheral surface of the spacer body 5 in a stepped manner from the central portion toward each end in the axial direction of the insulating spacer 3. An uneven portion 6 is formed. The concavo-convex portion 6 is formed to roughen the surface of the spacer main body 5 on the order of several microns, for example. Thereby, the uneven portion 6 functions so as to inhibit the movement of electrons, and suppresses the charging of the spacer body 5 itself.

  Next, the structure of the mold 25 for manufacturing (casting) the post-shaped insulating spacer 3 will be described. As shown in FIG. 4, the mold 25 includes a mold body 26 having a movable mold part 29 and a fixed mold part 30, and a movable mold part 29 and a fixed mold part 30 fixed to each other. Mold fixing plates 37 and 38, and nestings 27 and 28 mounted inside the movable mold part 29 and the fixed mold part 30, respectively.

In the mold body part 26 constituted by the movable mold part 29 and the fixed mold part 30, a cavity (mold cavity) 31 filled with a casting material and the outside of the mold 25 (mold) A material injection port 32 communicating from the bottom of the mold body 26 to the cavity 31 is formed. The cavity 31 is obtained by heat-curing the casting material filled in the cavity 31 to obtain the spacer body 5 having a volume exceeding 7000 cc (cm ³ ) and a maximum wall thickness exceeding 170 mm as a cast product. It is configured in a shape that can.

  For example, a hydraulic cylinder 39 is coupled to a mold fixing plate 37 that fixes the movable mold part 29. The cylinder 39 opens and closes the mold 25 by advancing and retracting the movable mold part 29 together with the mold fixing plate 37 with respect to the fixed mold part 30. Further, the casting material transferred through the material transfer pipe 34 is transferred to the bottom of the mold body 26 in the mold 25 into the cavity 31 of the mold body 26 through the material injection port 32. A material injection nozzle 33 for injection (filling) is arranged.

  On the base end side of the material transfer pipe 34, a material injection nozzle 33 and a material injection port 32 are provided with a liquid epoxy resin, which is a thermosetting casting material, in the cavity 31 of the mold body 26. For example, a cylinder mechanism having a piston for replenishing pressure is connected.

  In addition, the mold main body portion 26 including the movable side mold portion 29 and the fixed side mold portion 30 incorporates a plurality of rod-shaped heaters that can be controlled in temperature, for example. Here, when the insulating spacer 3 is cast, the vicinity of the material injection port 32 below the cavity 31 in the mold main body 26 shown in FIG. On the other hand, the part above the cavity 31 in the mold body 26 shown in FIG. 4 is heated to about 130 ° C. to 140 ° C., for example.

  Thus, when the insulating spacer 3 is cast, in order to prevent the casting material in the vicinity of the material inlet 32 from being first thermally cured during the casting transition period, The temperature inside the mold main body 26 is controlled with a temperature gradient such that the temperature near the material injection port 32 is lower, for example, by about 10 ° C. to 20 ° C. compared to the upper part of the cavity 31 of FIG. The

  Also, as shown in FIGS. 4 and 5 (and FIG. 9 to be referred to later), the mold body portion 26 has nests 27 and 28 in which embedded metal fittings 7 and 8 are mounted via O-rings 35 and 36, respectively. The cavity 31 described above is formed between the inserts 27 and 28 so as to surround the entire outer peripheral surfaces of the embedded metal fixtures 7 and 8 respectively.

  That is, as shown in FIGS. 4 and 5, the cavity 31 has peripheral covering portion forming grooves 29 a and 30 a for forming the peripheral covering portion 9 of the spacer main body portion 5 shown in FIG. 3. By providing the peripheral covering portion forming grooves 29a and 30a, the peripheral covering portion 9 on the spacer main body 5 is allowed to have a peripheral edge (embedded metallic portion 7) as shown in FIGS. , 8 is formed at a position covering the rims 27 and 28 on the side facing the inserts 27 and 28.

  Providing such a peripheral edge covering portion 9 on the spacer main body 5 eliminates a minute gap between the embedded metal articles 7 and 8 and the mold main body 26 on the mold structure, and the embedded metal articles 7 and 8. It is possible to substantially prevent the occurrence of thin-walled burrs around the periphery of the mold after casting.

  Here, in the mold having the other structure shown in FIG. 6 illustrated for comparing the structure with the mold 25 of the present embodiment, the gap between the embedded mold 42 attached to the insert 43 and the mold main body 40 is between. When the casting material enters into the minute gap 45, the burrs are generated at the peripheral edge of the embedded metal 42. When a burr occurs, for example, an artificial deburring operation using a processing jig having a needle-like tip is required, and a long work time of, for example, about 10 minutes per insulating spacer is required. become. Moreover, when performing such a deburring operation, a defective product of about 1 to 2% per total production number of cast products is caused by an operation error.

  On the other hand, in the mold 25 of the present embodiment, in addition to providing the peripheral edge covering portion forming grooves 29a and 30a, as shown in FIG. 5, the O-rings 35 and 36 described above are provided with the peripheral edge covering portion forming grooves 29a. , 30a is interposed between the embedded metal fixtures 7 and 8 and the inserts 27 and 28, and is installed so as to span the gap between the embedded metal fixtures 7 and 8 and the mold body 26. It is. Therefore, as shown in FIGS. 4 and 5, in the mold 25, the gap between the embedded metal fixtures 7 and 8 and the inserts 27 and 28 and the gap between the embedded metal fixtures 7 and 8 and the mold body 26 are included. The casting material can be prevented more reliably. Thereby, since the time spent for deburring work etc. can be reduced, the productivity of the insulating spacer 3 can be improved.

  Further, as shown in FIG. 7, in order to cast the concavo-convex portion 6 on the peripheral surface of the spacer main body 5 shown in FIG. 3 on the inner wall surface constituting the cavity 31 in the mold main body 26, Concave and convex portions 29 b and 30 b corresponding to the shape of the concave and convex portion 6 are formed. That is, the concavo-convex portions 29 b and 30 b form a plurality of steps in a stepped manner from the central portion (partition side) of the cavity 31 toward each end portion in the opening and closing direction of the mold 25.

  Here, as shown in FIGS. 7 and 8, the uneven portions 29 b and 30 b on the cavity 31 are the uneven portions 29 b and 30 b of the casting material 51 injected into the cavity 31 from the material injection port 32. An inclined portion 50 is provided to assist (support) the flow of the liquid. When the opening and closing direction of the mold 25 is set to a reference angle of 0 °, the inclined portion 50 is a taper that rises at an inclination angle k of, for example, 5 ° from the central portion of the cavity 31 toward each end. It is configured.

  That is, the inclined portion 50 is not a so-called punching taper for improving die cutting, but smoothly casts the casting material 51 injected from the material injection port 32 as shown in FIG. By making it flow above, it is for improving air bleedability and preventing air bubbles from remaining during casting. Thereby, in a cast product, since generation | occurrence | production of the void (hole) used as the factor of the electrical insulation performance fall can be suppressed, the insulation spacer 3 with favorable electrical insulation performance can be cast.

  On the other hand, in the mold in which the inclined portion 50 is not provided in the uneven portion (the above-described inclination angle is 0 °), about 5% of the total number of cast products will cause voids. Become. That is, convection of the casting material may occur in the uneven portion where the inclined portion 50 is not provided, and air may be trapped in the uneven portion. At this time, the flow of the casting material is hindered by the air trapped in the concavo-convex portion, and there is a possibility that a desired shape cannot be obtained as a cast product. On the other hand, in the mold 25 of the present embodiment in which the inclined portions 50 are provided in the uneven portions 29b and 30b (the above-described inclination angle is 5 °), the fluidity of the casting material on the uneven portions 29b and 30b. Is good, and it becomes possible to bring the generation rate of voids close to 0%.

  Next, in addition to FIGS. 3 and 4 described above, a method for manufacturing a cast product according to the present embodiment, which is useful when manufacturing the insulating spacer 3 having such a structure, is shown in FIGS. This will be described with reference to FIG. 11E. Here, the manufacturing method of the cast product of this embodiment is a casting method obtained by further improving the so-called pressure gelation method.

  First, as shown in FIG. 9 (illustration is omitted for the fixing side of the mold 25), each of the embedded metal fixtures 7 and 8 is placed on the corresponding side while sandwiching the O-rings 35 and 36 inside. Mount on the nestings 27 and 28. Next, the inserts 27 and 28 to which the O-rings 35 and 36 and the embedded metal fixtures 7 and 8 are attached are respectively set (attached) to the movable mold part 29 and the fixed mold part 30 of the mold body 26. To do.

  Subsequently, as shown in FIG. 4, the mold 25 in which the inserts 27 and 28 are set is closed via the cylinder 39, and then the inside of the mold main body 26 in the mold 25 is heated. At this time, the portion excluding the vicinity (periphery) of the material injection port 32 in the mold main body 26 shown in FIG. 4 is heated to 140 ° C., and the vicinity of the material injection port 32 is heated to 130 ° C., which is 10 ° C. lower. As described above, the temperature adjustment is performed by controlling the heater in the mold body 26. Such temperature adjustment is performed in order to suppress thermosetting of the casting material 51 at the material injection port 32.

Next, after the inside of the mold main body 26 is adjusted to the above temperature, as shown in FIG. 10, the injection speed 50 cc (into the cavity 31 of the mold main body 26 through the material injection nozzle 33 and the material injection port 32. A liquid epoxy resin which is a thermosetting casting material 51 is injected at cm ³ ) / sec. In this case, by controlling a cylinder mechanism including a piston on the base end side of the material transfer pipe 34, the resin is cured by a crosslinking reaction into the cavity 31 of the heated mold body 26 (mold 25). The casting material 51 is replenished with pressure so as to compensate for the volume shrinkage at the time.

  As shown in FIG. 11A, the outer peripheral portion 52 of the casting material 51 in the cavity 31 of the mold body 26 (mold 25) by such pressurization of the casting material 51 (replenishment while applying pressure). Is thermally cured to obtain a semi-cured product 53. Furthermore, by continuing this pressurization of the casting material 51, a crosslinking reaction occurs when the thermosetting of the semi-cured product 53 obtained in the mold main body portion 26 proceeds toward the center portion 54 side. With this reaction heat, the semi-cured product 53 is internally heated from the central portion 54.

Here, in the case of the present embodiment, in order to obtain a large spacer main body 5 having a volume exceeding 7000 cc (cm ³ ) and having a maximum thickness exceeding 170 mm, a large amount is contained in the cavity 31 corresponding to this size. Casting material 51 is injected. For this reason, the reaction heat at the time of curing the material on the central portion 54 side of the semi-cured product 53 is enclosed by the outer peripheral portion 52 that has been thermally cured first, and internal heat generation from the central portion 54 of the semi-cured product 53 occurs.

  Next, as shown in FIG. 11B, according to the occurrence of thermal expansion of the semi-cured product 53 that has internally generated heat in the mold main body 26 (mold 25), for example, a casting material 51 that has been applied at a pressure of 2 bar. Stop the pressurization supply. At this time, the central portion 54 of the semi-cured product 53 in the cavity 31 is farther from the inner wall surface of the mold body 26 (cavity 31) and gradually heat cures. For this reason, the semi-cured product 53 repeats thermal expansion (self-expansion) from the central portion 54 side, and the volume shrinkage at the time of material curing in the cavity 31 is compensated by this self-expansion.

  Further, since the air is spontaneously pushed out from the cavity 31 by the self-expansion of the semi-cured product 53 due to such internal heat generation, it is not necessary to pressurize the casting material 51 for air venting. For this reason, when casting is performed with continuous replenishment of pressure, about 1% to 2% of the total number of cast products produced, causing cracks in the cast products, but semi-curing After the occurrence of self-expansion of the object 53, it becomes possible to make the rate of occurrence of cracks as close to 0% as possible by eliminating the need to pressurize the casting material 51. Note that the timing for stopping such pressurization is based on the start of injection of the casting material 51 into the cavity 31 based on the experimental data of the casting to which the mold 25 of the present embodiment is applied. Examples include stopping the pressurization after a predetermined time has elapsed.

  Next, after a predetermined time has passed since the pressurization of the casting material 51 was stopped, as shown in FIG. 11C (the illustration of the fixing side of the mold 25 is omitted), from the cavity 31 of the mold 25. Then, the semi-cured product 53 is taken out (released), and the O-rings 35 and 36 and the inserts 27 and 28 are removed from the semi-cured product 53.

  Next, as shown in FIG. 11D, the semi-cured product 53 taken out from the mold 25 is left for about 30 minutes and the internal heat generation of the semi-cured product 53 is continued. As a result, the post-shaped insulating spacer (casting product) 3 having final physical properties as a solid insulating material such as high heat resistance is obtained as shown in FIGS. 11E and 3. .

  Here, in the manufacturing method of the present embodiment, the inner heat generation at the central portion 54 side can be contained in the outer peripheral portion 52 of the semi-cured product 53 that has been previously heat-cured. The step of placing the cast product taken out from the above in a heating furnace for about 12 hours and performing secondary curing can be substantially eliminated. Therefore, in the manufacturing method of this embodiment, the production cycle of the insulating spacer 3 can be significantly shortened, and the production efficiency can be remarkably improved.

  As described above, according to the method for manufacturing a cast product according to the present embodiment, the semi-cured product 53 obtained by thermosetting the outer peripheral portion 52 in the mold 25 can be internally heated to self-expand. After this self-expansion, it is unnecessary to apply pressure to the casting material 51. This makes it possible to avoid the occurrence of cracks due to excessive replenishment (pressurization) of the casting material 51, the occurrence of thin skin (double skin) on the surface of the casting, and the occurrence of sink marks, respectively. A high quality insulating spacer 3 can be obtained.

  Furthermore, according to the method for manufacturing a cast product according to the present embodiment, after the semi-cured product 53 that has been internally heated is taken out from the mold 25, the outer peripheral portion 52 that has been cured first is used to the outside. Since this internal heat generation can be continued while preventing heat dissipation, complicated temperature control to prevent the vicinity of the material injection port 32 in the mold 25 from being blocked (thermosetting first), or completely It is not necessary to separately cure the cast product that has not been cured in a heating furnace, and the productivity of the insulating spacer 3 can be increased.

  In addition, according to the casting manufacturing method to which the mold 25 of the present embodiment is applied, as described above, the peripheral covering portion forming grooves 29a and 30a shown in FIGS. 4 and 5 and FIGS. By providing the illustrated inclined portion 50 in the cavity 31 of the mold main body portion 26, it is possible to suppress the generation of burrs and voids in the insulating spacer 3 which is a cast product. Further, the post-shaped insulating spacer 3 with improved quality as a solid insulator is applied to the supporting portion of the high voltage conductor 22 as shown in FIGS. The reliability of the grounding portion of the switchgear 1 can be ensured.

  Although the present invention has been specifically described above with reference to the embodiment, the present invention is not limited to this embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the form in which the embedded metal piece is cast integrally has been illustrated, but instead of this, a cast product without the embedded metal mold is cast by the manufacturing method of the present invention. Also good.

  DESCRIPTION OF SYMBOLS 1 ... Gas insulation switchgear, 3 ... Post-shaped insulating spacer, 5 ... Insulating spacer main body, 6 ... Uneven part of insulating spacer main body, 7, 8 ... Embedded metal, 9 ... Perimeter covering part, 25 ... Mold, 26 ... Die body part, 27, 28 ... Nest, 29a, 30a ... Periphery covering part forming groove, 29b, 30b ... Irregular part of cavity, 31 ... Cavity, 32 ... Material injection port, 35, 36 ... O-ring, 35 ... Cylinder, 50 ... inclined part, 51 ... casting material, 52 ... outer peripheral part, 53 ... semi-cured product, 54 ... center part.

Claims (4)

A step of heat-curing the outer peripheral portion of the casting material in the mold while pressurizing the thermosetting casting material in the heated mold to obtain a semi-cured product;
A step of causing the semi-cured product to generate heat internally from the central portion by reaction heat generated when heat curing of the semi-cured product obtained in the mold proceeds to the central portion side while continuing the pressurization. When,
In response to the occurrence of thermal expansion of the semi-cured product that has internally generated heat in the mold, stopping the pressurization of the casting material;
After stopping the pressurization and replenishing the volume shrinkage during curing by repeating thermal expansion from the center side of the semi-cured product in the mold, and
A step to eject the said semi-cured material from within the mold after a predetermined time has elapsed after stopping the pressurizing圧補supply,
The step of thermally curing the entire semi-cured product including the central portion by allowing the semi-cured product that has been taken out to stand for a predetermined time to continue internal heat generation;
A method for producing a cast product, comprising: The method for producing a cast product according to claim 1, wherein a cast product having a volume exceeding 7000 cm ³ and a maximum wall thickness exceeding 170 mm is cast. A mold for use in the method of manufacturing a cast product according to claim 1 or 2,
A nesting in which a metallic embedding member integrally formed with a cast product to be manufactured is attached via an O-ring ,
In the state set with nested the embedded member is mounted within, Rutotomoni a cavity which surrounds the entire outer peripheral surface of said embedded members between the nesting, this cavity, the leading therein In order to assist the flow of the casting material injected into the cavity from the injection port by providing an injection port of the casting material, the inner wall surface of the cavity is previously provided from the central portion toward the end side. A mold main body portion having a plurality of stepped steps formed of inclined portions having a determined angle ;
The metal mold | die characterized by comprising. While the mold is provided with a heater, when the thermosetting casting material is pressurized and refilled in the mold, the heater sets the temperature of the cavity higher than the temperature of the casting material inlet. The mold according to claim 3, wherein

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