JP2017200698A - Silicone rubber mold and production method of mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cool quickly and solidify liquid wax injected into a cavity.SOLUTION: A silicone rubber mold 10 has a cavity 14 formed inside and having a shape corresponding to an original mold having a prescribed shape, and also has first and second split molds 11, 12 half-split so that a wax pattern formed by solidifying liquid wax 16 injected into the cavity 14 can be taken out. The first and second split molds 11, 12 are provided with a heat radiation acceleration member 19 for accelerating radiation of heat of the liquid wax injected into the cavity 14.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a silicone rubber mold for producing a prototype wax model and a method for producing the silicone rubber mold.

  Conventionally, a rubber mold is produced based on a split mold having a shape obtained by dividing a hollow decorative part as a master model, and a wax is injected into the rubber mold to produce a split wax mold corresponding to the split mold. After the molds are combined to produce a hollow wax mold having a hollow shape, investment is injected into the container with the wax tree made using the hollow wax mold being placed in the container. A method for producing a hollow decorative part for spectacles, in which a mold is produced, and further, this raw mold is fired to produce a mold, a metal is poured into the mold and solidified, and then the mold is destroyed and the hollow decorative part is taken out and finished. Is disclosed (for example, see Patent Document 1).

  In this method of manufacturing a hollow decorative part for spectacles, first, silicone rubber is injected into the outer frame in a state where the split mold is disposed in the outer frame, and the split mold is slowly pressed by a pressing means from the vertical direction thereof. Then, the silicone rubber is heated and vulcanized. Next, after splitting the silicone rubber in half and taking out the split mold, a liquid wax (for example, animal secretions, resin, paraffin, Injection wax prepared by mixing plastic or the like, and the wax is cooled and solidified, then the silicone rubber mold is released and one split wax mold is taken out from the inside. The other split wax mold is produced in the same manner as described above. After these hollow wax molds are produced by butting the flange portions of the divided wax molds and heat-welded, a wax tree is produced using the hollow wax molds. Next, this wax-type tree is placed in a container, and a flowable gypsum is injected into the container to produce a raw mold. The raw mold is placed in a firing furnace and fired to burn the wax-type tree and solidify the gypsum to produce a mold having a hot water channel (cavity) in the shape of the wax-type tree. Furthermore, beryllium copper alloy is adopted as the cast metal material, the mold is heated to 650 ° C. to 750 ° C., and the cast metal material is heated to 1010 ° C. to 1120 ° C. to be melted. A metal material is poured into a mold runway (cavity). Then, after the cast metal material in the runner (cavity) is solidified, the mold is broken to take out the hollow decorative part and finish it. This completes the hollow decorative part.

  In the method for manufacturing a hollow decorative part for spectacles configured in this way, when producing a hollow decorative part having a certain length, the hollow part is removed from the mold when the precisely molded wax material is taken out. Since it can be taken out properly, there is almost no damage such as deformation or breakage of the wax material, the yield of the original pattern is extremely high, and an extremely dense decorative product can be produced. As a result, even a hollow decorative part for spectacles having a linear shape or a curved shape, or a hollow decorative part for spectacles with a variation in thickness can be easily formed.

  On the other hand, a wax pattern manufacturing method is disclosed in which a mold plate with a molding space formed on the upper surface is filled with molten wax, the mold plate is closed with a lid plate, and pressure is applied to the mold plate and the lid plate to cool and solidify. (For example, refer to Patent Document 2). In this method for producing a wax pattern, first, with the original shape of a leaf placed on the bottom of the mold, the mold is filled with liquid silicone rubber and cooled to solidify. By removing the original shape from the silicone rubber template, a recess which is a molding space on the upper surface of the original shape is formed on the surface of the template. The lid mold plate is also made of silicone rubber in the same manner as the above template plate. On the lower surface of the lid mold plate, a recess that is a molding space of the original lower surface is formed. Next, a slightly larger amount of the wax melted into the concave portion of the template whose upper part is opened is solidified. As the wax, paraffin mixed with beeswax or pine ani is used. Next, the mold plate is closed by the lid mold plate, and the mold plate and the lid mold plate are installed as a set between the hot plate of the hot press, and the movable platen is operated to heat by the heat of the hot plate and simultaneously compress. Then, the molten excess wax is discharged and the thickness of the wax is adjusted according to the original shape. Further, after the wax in the recess is cooled and solidified, the wax pattern that is a wax model is taken out. As a result, since the wax is surely filled up to a fine plane, a precise thin planar wax pattern can be produced. In addition, it casts by the lost wax casting method using this wax pattern. That is, in the state where a mold material such as gypsum is packed around a thin flat wax pattern which is a wax model, after heating and flowing out the wax, the molten metal is poured into the mold. As a result, it is possible to cast metal jewelry, crafts, industrial accessories and the like having the same shape as the leaves.

JP 2001-121244 A (Claim 1, paragraphs [0020] to [0034], [0044], FIGS. 3 to 6) JP-A-8-57871 (Claim 1, paragraphs [0001], [0009] to [0015], FIGS. 1 to 5)

  In the method for manufacturing a hollow decorative part for spectacles disclosed in the above-mentioned conventional patent document 1, liquid wax such as paraffin is injected into the interior (cavity) of a silicone rubber mold in which a pair of halves are bonded together. Although the thermal conductivity of silicone rubber is extremely low at about 0.2 W / (m · K), it is necessary to cool wax such as paraffin inside the silicone rubber mold (cavity). There was a problem that took a lot of time. Further, in the method for producing a wax pattern disclosed in the above-mentioned conventional patent document 2, a mold plate is formed by a silicone rubber lid mold plate in a state where a relatively large amount of wax such as paraffin is poured into the recesses of the silicone rubber mold plate. Is closed and heated and compressed in a state where the mold plate and the cover mold plate are placed between the hot press hot plates, so that excess molten wax flows out, and the thickness of the wax is reduced according to the original shape. After the adjustment, the wax in the recess is cooled and solidified, but the silicone rubber has a very low thermal conductivity of about 0.2 W / (m · K) as described above. There has been a problem that it takes a long time to cool wax such as paraffin in the recesses between the plate and the lid plate.

  An object of the present invention is to provide a silicone rubber mold that can quickly cool and solidify liquid wax injected into a cavity and a method of manufacturing the mold. Another object of the present invention is a silicone rubber mold that can quickly cool and solidify the liquid wax injected into the cavity with a slight increase in the number of manufacturing steps of mixing metal powder with the raw material of the liquid silicone rubber. It is in providing the manufacturing method of.

  The first aspect of the present invention is that, as shown in FIGS. 1 to 3, a cavity 14 having a shape corresponding to a prototype 13 having a predetermined shape is formed therein, and liquid wax 16 is injected into the cavity 14 and solidified. A silicone rubber mold 10 having first and second split molds 11 and 12 halved so that the wax model 17 can be taken out, and promoting heat dissipation to promote heat dissipation of the liquid wax 16 injected into the cavity 14 The member 19 is provided in the first and second split molds 11 and 12.

  The second aspect of the present invention is an invention based on the first aspect, and further, as shown in FIG. 1, the heat radiation promoting member 19 is dispersed in the first and second split molds 11 and 12. It has the metal powder 19a of conductivity 15-418W / (m * K), and the heat sink 19b, 19c closely_contact | adhered to the outer peripheral surface of the 1st and 2nd split molds 11 and 12.

  A third aspect of the present invention is an invention based on the first aspect, and further, as shown in FIG. 5, the heat radiation promoting member 59 is close to the cavity 54 in the first and second split molds 51 and 52. And the tubes 61 and 62 embedded therein and the cooling fluid pressurizing device 63 for circulating the cooling fluid in the tubes 61 and 62.

  As shown in FIGS. 1 and 2, the fourth aspect of the present invention is a step of installing a prototype 13 having a predetermined shape in a rubber mold 21, and a liquid silicone rubber material having a thermal conductivity of 15 to 418 W / (m · K) metal powder 19a is mixed to prepare a dispersion 23, the dispersion 23 is poured into a rubber mold 21 and solidified, and the solidified silicone rubber mold 10 is divided in half. In this way, the step of producing the first and second split molds 11 and 12 having the cavity 14 having a shape corresponding to the master mold 13 by removing the master mold 13 from the silicone rubber mold 10, and the first and second split molds 11 and 12 And a step of bringing the radiator plates 19b and 19c into close contact with the outer peripheral surface of the silicon rubber mold.

  As shown in FIGS. 5 and 6, the fifth aspect of the present invention is the step of installing a prototype 53 having a predetermined shape in the rubber mold 72 and the inside of the rubber mold 72 so as to be close to the prototype 53. The steps of disposing the tubes 61 and 62, the step of pouring the raw material of the liquid silicone rubber 77 into the rubber mold 72 and solidifying, the half of the solidified silicone rubber die 50 being divided into the original mold from the silicone rubber die 50 The step of producing the first and second split molds 61 and 62 having the cavity 54 having a shape corresponding to the original mold 53 by taking out the 53, and the cooling fluid is circulated in the tubes 61 and 62 at one end of the tubes 61 and 62. And a step of connecting a cooling fluid pressurizing device 63 to be manufactured.

  In the silicone rubber mold according to the first aspect of the present invention, since the heat radiation promoting member is provided in the first and second splits, the heat of the liquid wax injected into the cavity is quickly dissipated by the heat radiation promoting member. As a result, since the liquid wax in the cavity is cooled and solidified in a short time, it is possible to shorten the time until the wax model is taken out from the cavity after the liquid wax is injected into the cavity. Therefore, when a relatively large number of wax models are produced using a single silicone rubber mold, the production time can be shortened, which is suitable for mass production.

  In the silicone rubber mold according to the second aspect of the present invention, the heat radiation promoting member includes a metal powder having a thermal conductivity of 15 to 418 W / (m · K) dispersed in the first and second molds, Since it has a heat sink closely attached to the outer peripheral surface of the second split mold, the speed of transmitting the organosilicon polymer in the first and second split molds is slow, but the speed of transmitting the metal powder in the first and second split molds Is extremely fast. As a result, the heat of the liquid wax injected into the cavity is transferred to the outer peripheral surfaces of the first and second split molds relatively quickly through the organosilicon polymer and the metal powder in the first and second split molds, and the heat sink Will be released immediately. As a result, similarly to the above, the liquid wax in the cavity is cooled and solidified in a short time, so that the time from the injection of the liquid wax into the cavity until the removal of the wax model from the cavity can be shortened. Accordingly, as described above, when a relatively large number of wax models are manufactured using a single silicone rubber mold, the manufacturing time can be shortened, which is suitable for mass production.

  In the silicone rubber mold according to the third aspect of the present invention, the heat radiation promoting member includes a tube embedded in the first and second split molds in the vicinity of the cavity, and cooling fluid pressurization for circulating the cooling fluid in the tube. Therefore, the heat of the liquid wax injected into the cavity is transferred to the cooling fluid flowing through the tube and quickly dissipated out of the silicone rubber mold. As a result, similarly to the above, the liquid wax in the cavity is cooled and solidified in a short time, so that the time from the injection of the liquid wax into the cavity until the removal of the wax model from the cavity can be shortened. Accordingly, as described above, when a relatively large number of wax models are manufactured using a single silicone rubber mold, the manufacturing time can be shortened, which is suitable for mass production.

  In the method for producing a silicone rubber mold according to the fourth aspect of the present invention, an original mold having a predetermined shape is placed in a rubber mold, and a dispersion is prepared by mixing metal powder with a raw material of liquid silicone rubber. After the liquid is poured into a rubber mold and solidified, the solidified silicone rubber mold is divided in half, and the mold is taken out from the silicone rubber mold, thereby having first and second molds having cavities corresponding to the mold. In addition, since the heat radiation plate is closely attached to the outer peripheral surfaces of the first and second split molds, the speed of transmission through the organosilicon polymer in the first and second split molds is slow, but the first and second split molds As a result, the speed of the liquid wax injected into the cavities becomes extremely high, so that the heat of the liquid wax injected into the cavity is transferred relatively quickly through the organosilicon polymer and the metal powder in the first and second molds. 20% type Reaches the outer peripheral surface is dissipated rapidly from the heat radiating plate. As a result, similarly to the above, the liquid wax in the cavity is cooled and solidified in a short time, so that the time from the injection of the liquid wax into the cavity until the removal of the wax model from the cavity can be shortened. Accordingly, as described above, when a relatively large number of wax models are manufactured using a single silicone rubber mold, the manufacturing time can be shortened, which is suitable for mass production. Further, compared with the conventional method for producing a silicone rubber mold, the method for producing a silicone rubber mold of the present invention has a relatively simple process of preparing a dispersion by mixing a metal powder with a raw material of liquid silicone rubber. Since only addition is required, only a slight increase in manufacturing steps is required.

  In the method for producing a silicone rubber mold according to the fifth aspect of the present invention, an original mold having a predetermined shape is placed in a rubber mold, and a tube is arranged in the rubber mold so as to be close to the original mold. After the rubber raw material is poured into a rubber mold and solidified, the solidified silicone rubber mold is divided in half, and the original mold is taken out from the silicone rubber mold, whereby first and second cavities having shapes corresponding to the original mold are obtained. Since the split mold was made and a cooling fluid pressurizing device for circulating the cooling fluid in the tube was connected to one end of the tube, the heat of the liquid wax injected into the cavity was transferred to the cooling fluid circulating in the tube. It is quickly dissipated out of the silicone rubber mold. As a result, similarly to the above, the liquid wax in the cavity is cooled and solidified in a short time, so that the time from the injection of the liquid wax into the cavity until the removal of the wax model from the cavity can be shortened. Accordingly, as described above, when a relatively large number of wax models are manufactured using a single silicone rubber mold, the manufacturing time can be shortened, which is suitable for mass production.

It is a longitudinal cross-sectional block diagram of the silicone rubber type | mold of 1st Embodiment of this invention. It is a section lineblock diagram showing the manufacturing process of the silicone rubber type. It is a cross-sectional block diagram which shows the process after producing a wax model using this silicone rubber type | mold, and producing a gypsum type | mold using this wax model. FIG. 5 is a cross-sectional configuration diagram showing a process of forming a metal product by injecting a metal into a gypsum mold cavity after melting and discharging a wax model from the gypsum mold. It is a longitudinal cross-sectional block diagram of the silicone rubber type | mold of 2nd Embodiment of this invention. It is a section lineblock diagram showing the manufacturing process of the silicone rubber type.

  Next, an embodiment for carrying out the present invention will be described with reference to the drawings.

<First Embodiment>
As shown in FIGS. 1 and 3, the silicone rubber mold 10 has a cavity 14 having a shape corresponding to the original mold 13 having a predetermined shape, and a wax model 17 in which liquid wax 16 is injected into the cavity 14 and solidified. The first and second split molds 11 and 12 are divided in half so as to be removable. In this embodiment, since the prototype 13 is an article formed in a bowl shape, the cavity 14 is also formed in a bowl shape that is a shape corresponding to the prototype 13. The first split mold 11 is formed with an outer surface of a cavity 14 for producing a bowl-shaped wax model 17, and a runner 18 for pouring the liquid wax 16 into the cavity 14 is divided vertically. Is formed. The second split mold 12 is formed with the inner surface of the cavity 14 for producing the bowl-shaped wax model 17 and the other half of the runner 18 for vertically flowing the liquid wax 16 into the cavity 14. Is formed. Furthermore, the first and second split molds 11 and 12 are provided with a heat radiation promoting member 19 that promotes heat dissipation of the liquid wax 16 injected into the cavity 14. In this embodiment, an article formed in the shape of a bowl is used as the prototype. However, the prototype is an article having a spherical shape, a rectangular parallelepiped shape, a polygonal shape, or a shape that cannot be molded by a general resin or metal injection molding method. Or an article having a complicated shape formed by using a 3D printer. Here, the prototype may be an article having a shape that cannot be molded by a general resin or metal injection molding method, or may be an article having a complicated shape formed by using a 3D printer. Even if a cavity of a shape corresponding to the original shape of the shape is formed in the silicone rubber mold, the original shape can be taken out by elastically deforming the silicone rubber mold without damaging it, and liquid wax is put in the cavity. This is because the wax model solidified by pouring can be taken out by elastic deformation without damaging the silicone rubber mold.

  On the other hand, in this embodiment, the heat radiation promoting member 19 is in close contact with the metal powder 19a dispersed in the first and second split molds 11 and 12, and the outer peripheral surfaces of the first and second split molds 11 and 12, respectively. First and second heat radiating plates 19b, 19c. The metal powder 19a is preferably a metal powder having a thermal conductivity in the range of 15 to 418 W / (m · K). Examples of the metal powder 19a having a thermal conductivity in the range of 15 to 418 W / (m · K) include powders of aluminum, aluminum-bronze alloy, iron, stainless steel, copper, silver, tungsten, brass, magnesium, and the like. Can be mentioned. Moreover, the average particle diameter of the metal powder 19a is preferably 10 μm or less, and more preferably in the range of 3 to 10 μm. Furthermore, the mixing ratio of the metal powder and the silicone rubber, that is, the metal powder / silicone rubber is preferably in the range of 1/10 to 5/10 in volume ratio.

Here, the preferable thermal conductivity of the metal powder 19a is limited to the range of 15 to 418 W / (m · K) because, if it is less than 15 W / (m · K), the heat of the wax model in the cavity is rapidly increased. This is because no metal powder exceeding 418 W / (m · K) can be released. Moreover, the upper limit of the preferable range of the average particle diameter of the metal powder 19a is limited to 10 μm. When the average particle diameter exceeds 10 μm, the shape transferability of the silicone rubber mold 10 is deteriorated and the function as the silicone rubber mold 10 is lost. Because. Further, the lower limit of the more preferable range of the average particle diameter of the metal powder 19a is limited to 3 μm, the metal powder 19a is aggregated if less than 3 μm, it is difficult to uniformly disperse the metal powder 19a in the liquid silicone rubber, Moreover, it is because the handling of the metal powder 19a is hindered. Furthermore, the preferable range of the metal powder / silicone rubber is limited to the range of 1/10 to 5/10 in terms of mass ratio. The thermal conductivity of the first and second split molds 11 and 12 is less than 1/10. The time for the liquid wax 16 in the cavity 14 to solidify decreases and the elastic force of the silicone rubber mold 10 decreases and the elastic function as the silicone rubber mold 10 is lost when it exceeds 5/10. Because. The average particle size of the metal powder 19a was measured with a laser diffraction / scattering particle size distribution measuring device (LA-950, manufactured by Horiba, Ltd.), and the 50% average particle size (D ₅₀ ) calculated using the particle size standard as the number. Say. The number-based average particle diameter measured by the laser diffraction / scattering particle size distribution measuring apparatus is the value of any 50 particles in an image observed with a scanning electron microscope (S-4300SE and S-900 manufactured by Hitachi High-Technologies). It almost coincides with the average particle diameter when the particle diameter is actually measured.

  A method for manufacturing the silicone rubber mold 10 configured as described above will be described with reference to FIGS. First, the prototype 13 having a predetermined shape is installed in the rubber mold 21 (FIG. 2A). In this embodiment, the prototype 13 is formed in a bowl shape, and is placed on a rectangular block 22 made of silicone rubber in which the metal powder 19a is dispersed. At this time, it is preferable to temporarily fix the master 13 by bonding it to the rectangular parallelepiped block 22 with an adhesive. Next, a dispersion 23 is prepared by mixing a liquid silicone rubber material with a metal powder 19a having a thermal conductivity of 15 to 418 W / (m · K) at a predetermined mixing ratio. Here, as the liquid silicone rubber, a one-pack type silicone rubber in which a main agent and a curing agent are mixed in advance, or a two-pack type silicone rubber in which the main agent and a curing agent are packaged separately and cured by mixing them. However, it is preferable to use a two-component silicone rubber having good storage stability. Examples of the two-pack type silicone rubber include KE-1310T manufactured by Shin-Etsu Silicone, and HT45 TRANSPARENT manufactured by Zhermack, Italy. Further, the rectangular block 22 made of silicone rubber in which the metal powder 19 a is dispersed is produced using this dispersion liquid 23.

  Next, the dispersion liquid 23 is poured into the rubber mold 21 and solidified (FIG. 2B). Then, after the solidified silicone rubber mold 10 is taken out from the rubber mold 21 and divided in half (FIG. 2C), the prototype 13 is taken out from the silicone rubber mold 10 (FIG. 2D). Thus, the first and second split molds 11 and 12 having the cavity 14 having a shape corresponding to the original mold 13 are produced. Here, when the silicone rubber mold 10 is divided in half, it is preferable that the mating surfaces 11a and 12a of the first and second molds 11 and 12 are not formed in a flat shape but are formed in an uneven surface. This is to increase the frictional resistance by increasing the area of the mating surfaces 11a, 12a of the first and second split molds 11, 12 that are in close contact with each other, and also to match the mating surfaces of the first and second split molds 11, 12 11a and 12a are formed not by a plane parallel to the mating surface direction but by a plurality of surfaces having angles different from the mating surface, thereby moving the first and second split molds 11 and 12 in the mating surface direction. This is to increase the resistance to the deviation. The first and second split molds 11 and 12 are formed with a runner 18 for allowing the liquid wax 16 to flow into the cavity 14 in communication with the cavity 14. Further, the first and second radiator plates 19b and 19c are brought into close contact with the outer peripheral surfaces of the first and second split molds 11 and 12, respectively (FIG. 1). The first and second heat radiating plates 19b and 19c are preferably formed of a plate made of aluminum, copper, brass or the like. In addition, a plurality of fins (not shown) can be erected on the first and second heat radiating plates 19b and 19c in order to further improve the heat radiation performance. Furthermore, a circuit for flowing a cooling medium such as water or oil may be provided inside the first and second radiator plates 19b and 19c.

  A method for producing the wax model 17 using the silicone rubber mold 10 thus manufactured will be described with reference to FIGS. First, the silicone rubber mold 10 is installed so that the entrance of the runner 18, that is, the gate 18 a faces the upper surface (FIG. 3A). At this time, the silicone rubber mold 10 is clamped, that is, the first and second radiator plates 19b, 19c is pressed in the direction approaching each other. Next, the liquid wax 16 is poured from the gate 18a. Thereby, the liquid wax 16 flows into the cavity 14 through the runner 18 (FIG. 3B). If the liquid wax 16 is allowed to stand at room temperature in a state of being poured into the cavity 14 at a temperature about 15 ° C. higher than its melting point, the speed of traveling through the organosilicon polymer in the first and second split molds 11 and 12 is slow, Since the speed at which the metal powder 19a in the first and second split molds 11 and 12 is transmitted becomes extremely high, the heat of the liquid wax 16 injected into the cavity 14 is heated by the organosilicon in the first and second split molds 11 and 12. The polymer and the metal powder are transmitted to the outer peripheral surfaces of the first and second split molds 11 and 12 relatively quickly and are quickly dissipated from the first and second radiator plates 19b and 19c. As a result, since the liquid wax 16 in the cavity 14 is cooled and solidified in a short time, the time from the injection of the liquid wax 16 into the cavity 14 until the removal of the wax model 17 from the cavity 14 can be shortened. Accordingly, when a relatively large number of wax models 17 are produced using a single silicone rubber mold 10, the production time can be shortened, which is suitable for mass production. Further, in comparison with the conventional manufacturing method of the silicone rubber mold, in the manufacturing method of the silicone rubber mold 10 of this embodiment, the dispersion 23 is prepared by mixing the metal powder 19a with the raw material of the liquid silicone rubber. Since only a simple process is added, only a slight increase in manufacturing steps is required. The wax model 24 with sprue solidified in the cavity 14 is taken out from the silicone rubber mold 10 (FIG. 3C), and the sprue 26 is cut off from the wax model 24 with sprue to complete the wax model 17 ( FIG. 3 (d)). Here, the sprue 26 is formed in a shape corresponding to the runner 18 and formed integrally with the wax model 17 and is necessary when the wax model 17 is manufactured. Is unnecessary.

  3 (d) to (f) and FIGS. 4 (g) to (k) show a method for producing a cast product 27 having the same shape as that of the original mold 13 by the lost wax method using the wax model 17 thus manufactured. This will be explained based on. First, the wax model 17 on the water absorbent paper 29 is installed (FIG. 3D). At this time, the wax model 17 is bonded to the water absorbent paper 29 with an adhesive. Then, the water absorbent paper 29 to which the wax model 17 is bonded is bonded to the gypsum mold (FIG. 3 (e)). Next, the gypsum 31 having fluidity is poured into the gypsum mold 28 and dried to produce a gypsum raw mold 32 (FIG. 3 (f)). Next, when the raw mold 32 is placed in a baking furnace together with the gypsum mold 28 and fired, the wax model 17 in the raw mold 32 is melted and flows out through the gate 33a, and the water absorbing paper 29 is burned out (see FIG. 4 (g)). As a result, a gypsum mold 34 in which a gypsum cavity 36 communicating with the gypsum runner 33 is formed is produced (FIG. 4H). Further, molten metal 37 is injected from the entrance of the gypsum runner 33, that is, from the gypsum gate 33a. Thereby, the molten metal 37 flows into the gypsum cavity 36 through the gypsum runner 33 (FIG. 4 (i)). After the molten metal 37 in the gypsum cavity 36 is solidified, the gypsum mold 34 is crushed and the cast product 38 with metal sprue is taken out (FIG. 4 (j)), and the metal sprue 39 is removed from the cast product 38 with metal sprue. By cutting off, a cast product 27 faithfully imitating the prototype 53 is completed (FIG. 4 (k)). Examples of the molten metal include noble metals such as gold, silver, and platinum, and alloys based on iron, and various metals that can be handled by precision casting such as copper alloys, aluminum alloys, and titanium alloys.

<Second Embodiment>
5 and 6 show a second embodiment of the present invention. In this embodiment, the heat radiation promoting member 59 of the silicone rubber mold 50 includes first and second tubes 61 and 62 embedded in the first and second split molds 51 and 52 in the vicinity of the cavity 54, And a cooling fluid pressurizing device 63 for circulating the cooling fluid in the first and second tubes 61 and 62. The first split mold 51 is formed with an outer surface of a cavity 54 for producing a bowl-shaped wax model, as in the first split mold of the first embodiment. One half is formed by vertically dividing the runner 58 for pouring. The second split mold 52 is formed with an inner surface of a cavity 54 for producing a bowl-shaped wax model, as in the second split mold of the first embodiment. The other half is formed by vertically dividing the runner 58 for pouring 56. However, the metal powder is not dispersed in the first and second split molds 51 and 52.

  On the other hand, the first tube 61 is embedded in the inside of the first split mold 51 in order to allow the cooling fluid to flow in a portion adjacent to the inner surface of the bowl-shaped cavity 54, and the second tube 62 is embedded in the inside of the second split mold 52. It is buried in order to flow the cooling fluid in a portion close to the inner surface of the bowl-shaped cavity 54. Here, “close to the inner surface of the cavity 54” means being located within a range of 2 to 15 mm from the curved outer inner surface of the bowl-shaped cavity 54 or the curved inner inner surface of the bowl-shaped cavity 54. The first and second tubes 61 and 62 are formed of a vinyl tube, a silicone rubber tube, a steel pipe, or the like. In this embodiment, air is pressurized as a cooling fluid and flows through the first and second tubes 61 and 62. Note that a gas other than air or a liquid such as water may be pressurized and flow through the first and second tubes. However, in this case, drainage treatment is necessary. Further, when the silicone rubber mold 50 is clamped, that is, when the first and second split molds 51 and 52 are brought into close contact with each other, the portion embedded in the first split mold 51 of the first tube 61 and the second A portion embedded in the split mold 52 communicates with the first mold 61 so as to become one first tube 61.

  On the other hand, in this embodiment, the cooling fluid pressurizing device 63 is a single small aquarium air pump that operates with a power supply of 100 V and generates aeration in aquarium of ornamental fish such as goldfish and tropical fish. By this water tank air pump 63, the air is pressurized to become pressurized air, and this pressurized air is configured to circulate through the first and second tubes 61 and 62. Specifically, one end of an air tube 64 is connected to a pressurized air discharge port of the water tank air pump 63, and the other end of the air tube 64 is connected to a base portion of a T-shaped joint 66. Further, one branch portion of the T-shaped joint 66 is connected to one end of the first tube 61 via the intermediate tube 67 and the socket 68, and the other branch portion of the T-shaped joint 66 is connected via the intermediate tube 69 and the socket 71. Connected to one end of the second tube 62. Further, the other ends of the first and second tubes 61 and 62 are opened to the atmosphere. The configuration other than the above is the same as that of the first embodiment.

  A method for manufacturing the silicone rubber mold 50 configured as described above will be described with reference to FIGS. First, a prototype 53 having a predetermined shape is installed in the rubber mold 72 (FIG. 6A). In this embodiment, the prototype 53 is formed in a bowl shape, and is placed on a portal block 73 made of silicone rubber. At this time, it is preferable to temporarily fix the master 53 by adhering it to the portal block 73 with an adhesive. Next, the first and second tubes 61 and 62 are disposed in the rubber mold 72 so as to be close to the master 53. Here, the first tube 61 is disposed in the vicinity of the curved outer surface of the bowl-shaped master 53, and the longitudinal center of the first tube 61 is silicone rubber in a state where both ends are stretched over the upper edge of the rubber mold 72. It is placed on a rectangular parallelepiped block 74. At this time, it is preferable to temporarily fix the center of the first tube 61 in the longitudinal direction by adhering to the rectangular parallelepiped block 74 with an adhesive. The second tube 61 is disposed close to the curved inner surface of the bowl-shaped cavity 54, and both ends thereof are held by the holding members 76. The holding member 76 includes a pair of stays 76a and 76a installed on the upper end of the rubber mold 72, arm portions 76b fitted into the stays 76a and 76a, and first and second ends of the arm portions 76b. 2 has a pair of gripping portions 76c and 76c for gripping both ends of the tube 62, respectively.

  Next, the liquid silicone rubber 77 is poured into the rubber mold 72 and solidified (FIG. 6B). Then, after the solidified silicone rubber mold 50 is taken out from the rubber mold 72 and divided in half (FIG. 6C), the original mold 53 is taken out from the silicone rubber mold 50 (FIG. 6D). Thus, the first and second split molds 51 and 52 having the cavity 54 having a shape corresponding to the original mold 53 are manufactured. Here, when the silicone rubber mold 50 is halved, it is preferable to form the mating surfaces 51a and 52a of the first and second split molds 51 and 52 in a concavo-convex surface rather than in a planar shape. The first and second split molds 51, 52 are formed with a runner 58 communicating with the cavity 54 for pouring the liquid wax 56 into the cavity 54. Further, after removing the holding member 76 from the second tube 62, a water tank air pump 63 for circulating pressurized air into the tubes 61, 62 is connected to one end of the first and second tubes 61, 62 (see FIG. 5).

  In order to produce a wax model using the silicone rubber mold 50 manufactured in this way, when the liquid wax 56 is poured from the gate 58a and poured into the cavity 54, it is added to the first and second tubes 61 and 62. Except for circulating pressurized air, the method is substantially the same as the method for producing the wax model using the silicone rubber mold according to the first embodiment, and therefore, repeated description is omitted. When the liquid wax 56 is poured from the gate 58a and flows into the cavity 54, if pressurized air is circulated through the first and second tubes 61 and 62, the heat of the liquid wax 56 injected into the cavity 54 is increased. It is transmitted to the pressurized air flowing through the first and second tubes 61 and 62 and quickly dissipated out of the silicone rubber mold 50. As a result, as in the first embodiment, the liquid wax 56 in the cavity 54 is cooled and solidified in a short time, so that the liquid wax 56 is injected into the cavity 54 and the wax model is taken out from the cavity 54. Can be shortened. Therefore, as in the first embodiment, when a relatively large number of wax models are manufactured using a single silicone rubber mold 50, the manufacturing time can be shortened, which is suitable for mass production. In addition, the method for producing a cast product having the same shape as the original 53 by the lost wax method using the wax model manufactured in this way is the same as the original by the lost wax method using the wax model of the first embodiment. Since it is substantially the same as the method of producing a cast product having a shape, repeated description is omitted.

  Next, examples of the present invention will be described in detail together with comparative examples.

<Example 1>
A rectangular parallelepiped silicone rubber mold having length, width and height of 6 cm, 4 cm and 3 cm, respectively, was produced. The length, width and height of the cavity in this silicone rubber mold were 3 cm, 1.5 cm and 0.5 cm, respectively. As the silicone rubber, KE-1310T (two-part silicone rubber) manufactured by Shin-Etsu Silicone Co., Ltd. is used, and as the metal powder, the thermal conductivity is 16.3 W / (m · K) and the average particle size is SUS304 powder which is 10 μm was used. Moreover, the ratio of metal powder / silicone rubber was 1/10 in volume ratio. Furthermore, the thing made from aluminum whose vertical, horizontal, and height are 6 cm, 4 cm, and 0.5 cm, respectively was used as a heat sink.

<Comparative Example 1>
A silicone rubber mold was produced in the same manner as in Example 1 except that no metal powder was used.

<Comparative test 1 and evaluation>
Into the silicone rubber mold cavities of Example 1 and Comparative Example 1, liquid paraffin heated and melted at 80 ° C. was poured. And time until this liquid paraffin solidified was measured.

  As a result, the liquid paraffin injected into the cavity of the silicone rubber mold of Comparative Example 1 solidified in 60 seconds, whereas the liquid paraffin injected into the cavity of the silicone rubber mold of Example 1 was 20 seconds, 1 of Comparative Example 1. Solidified in a time of / 3.

10,50 Silicone rubber mold 11,51 1st mold 12,52 2nd mold 13,53 Prototype 14,54 Cavity 16,56 Liquid wax 17 Wax model 19,59 Heat radiation promoting member 19a Metal powder 19b, 19c Heat sink 21, 72 Rubber mold 23 Dispersion 61 First tube (tube)
62 Second tube (tube)
63 Water pump for water tank (cooling fluid pressurizing device)
77 Liquid silicone rubber

Claims (5)

A silicone rubber mold having a first and a second split mold in which a cavity having a shape corresponding to an original mold having a predetermined shape is formed, and liquid wax is injected into the cavity so that a solid wax model can be taken out. Because
A silicone rubber mold characterized in that a heat radiation accelerating member for promoting heat dissipation of the liquid wax injected into the cavity is provided in the first and second split molds.   The heat dissipation promoting member is in close contact with the metal powder having a thermal conductivity of 15 to 418 W / (m · K) dispersed in the first and second split molds, and the outer peripheral surfaces of the first and second split molds. The silicone rubber mold according to claim 1, further comprising a heat sink.   2. The heat dissipation promoting member according to claim 1, further comprising: a tube embedded in the first and second split molds in the vicinity of the cavity; and a cooling fluid pressurizing device for circulating a cooling fluid in the tube. Silicone rubber mold. Installing a prototype of a predetermined shape in a rubber mold,
A step of preparing a dispersion by mixing a metal powder having a thermal conductivity of 15 to 418 W / (m · K) with a raw material of liquid silicone rubber;
Pouring the dispersion into the rubber mold and solidifying;
Halving the solidified silicone rubber mold and taking out the original mold from the silicone rubber mold to produce first and second split molds having cavities corresponding to the original mold; and
A method of manufacturing a silicone rubber mold, comprising: attaching a heat sink to the outer peripheral surfaces of the first and second split molds. Installing a prototype of a predetermined shape in a rubber mold,
Disposing a tube in the rubber mold so as to be close to the prototype;
Pouring the raw material of the liquid silicone rubber into the rubber mold and solidifying it;
Halving the solidified silicone rubber mold and taking out the original mold from the silicone rubber mold to produce first and second split molds having cavities corresponding to the original mold; and
Connecting a cooling fluid pressurizing device for circulating a cooling fluid in the tube to one end of the tube.

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