JPH0442105B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a wax pattern mold for casting lost wax, a method for manufacturing the same, and a pin used therefor, for example, for manufacturing jewelry by casting. Regarding the body.

[Prior Art] Conventionally, accessories such as rings and brooches, ornaments, Buddhist statues, etc. have been manufactured by casting molten platinum, gold, silver, copper alloy, etc. using the lost wax method using plaster molds.

The production of jewelry etc. using the lost-wack casting method is
The process consists of creating a master pattern, creating a wax pattern mold, creating a wax pattern, creating a mold, and casting.

Therefore, an outline of an example of manufacturing a ring using the conventional lost wax casting method will be explained with reference to FIG.

First, create a master pattern (main prototype) (A in Figure 10). This main model 1 is made of silver, brass, copper, etc. using metal forging and metal engraving techniques.

Next, create a wax pattern mold. Prepare two sheets 2, 2 of natural raw rubber or silicone rubber that are large enough to fit into the mold (not shown), clean the surfaces of the rubber sheets 2, 2 with carbon tetrachloride, and in between, Insert the sprue forming metal fitting 1a and place it in the formwork (B in Fig. 10). Then, place plates such as aluminum on the top and bottom of the formwork, set it in a vulcanization press, heat it to 120°C to 150°C, and gradually apply pressure until it is sufficiently tightened. Further, the rubber is left as it is for a certain period of time to proceed with vulcanization of the rubber. Once the rubber is vulcanized in this way, it is removed from the press, the rubber mold 3' is taken out from the mold frame, and the upper mold 3a and lower mold 3b are cut with a scalpel 4 to create a wax pattern mold 3 (No. C in Figure 10). in this case,
In order to easily and accurately align the upper mold 3a and the lower mold 3b after separation, the upper mold 3a and the lower mold 3b are not simply cut straight so that the cut surfaces are flat, but are cut in a wave shape. The cut surface is made to have an uneven surface, and the wax pattern is easily removed near the main mold embedded in the rubber mold (or in other words, the cavity formed by the main mold). Cut while adjusting the position appropriately. Cutting this rubber requires considerable skill and experience, and how well you do it will affect the difficulty and quality of cutting out the wax pattern.

Next, create a wax pattern using the completed wax pattern mold. A mold release agent is applied to the inner surface, the upper and lower molds 3a and 3b are aligned, and press plates (not shown) are placed on both sides to clamp them so that they do not move. and wax injector (not shown)
The melted wax is injected into the rubber-shaped cavity at a predetermined pressure (D in Fig. 10). Wait for the wax to harden, then flip the mold (Fig. 10E) and take out wax pattern 5 (Fig. 10F). Then, burrs etc. are removed and shaped to complete wax pattern 5 (FIG. 10G). Then, several wax patterns 5 are planted in the sprue 6 made of wax (Fig. 10H). Next, water is added to the embedding agent 7 whose main raw material is gypsum to form a mold, and the mixture is stirred and degassed. On the other hand, over the wax pattern, the casting flask 8 is covered with a lid to prevent the embedding agent from flowing out from below, and the embedding material is poured into the flask until the wax pattern is filled (FIG. 10I). During the process, deaerate the flask (Fig. 10 J) and pour in the remaining embedding agent, filling the flask to the top edge.

The plaster mold is then dried and then dewaxed. Then, the mold is fired.

And finally, it is cast. A centrifugal casting method or the like is used for this purpose.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional wax pattern mold for casting lost wax, it is difficult to accurately align the upper mold and the lower mold. If this mold matching is not accurate, the adhesion will be poor and the shape of the cavity will not be accurate. In other words, with conventional wax pattern molds, it is difficult to accurately align and closely fit the upper and lower cut molds, and the upper and lower molds fit together in a misaligned manner, making it difficult to accurately shape the cavity. There is a problem that there is no In addition, when injecting wax into a wax pattern forming mold made by matching the upper and lower molds, press plates are placed on the upper and lower molds to prevent the mold from moving, and the upper and lower molds are clamped with pressure. The mold made of the material deforms, and the cavity also deforms. If the shape of the cavity is not accurate as described above, the shape of the wax pattern, in other words, the volume thereof, will vary, and as a result, the volume and weight of the cast product will also be affected. Particularly when it comes to jewelry that uses precious metals, it is a big problem that variations in weight occur during manufacture.

Furthermore, conventional wax pattern molds do not have a means for connecting the upper mold and the lower mold, which often causes inconvenience in terms of work and storage.

Furthermore, the conventional method for manufacturing a wax pattern mold for lost wax casting has the drawback that the cutting operation is time-consuming, such as the rubber mold having to be cut in a zigzag pattern.

In addition, the main mold generally has upper and lower parts, each corresponding to an upper mold and a lower mold, and when the mold is opened after molding, when the upper mold is turned over, a wax pattern remains on the lower mold, and a wax pattern is left on the lower mold. This is also taken into account during cutting work when cutting into upper and lower parts. Therefore, it is necessary to attach appropriate marks to the rubber mold before cutting to distinguish between the upper and lower parts, but in the past, there was no identification mark that could be seen at a glance from the appearance of the rubber mold, which was inconvenient during the cutting process. It was hot.

The present invention solves these drawbacks of the prior art, and aims to provide a wax pattern mold that can obtain a wax pattern with an accurate shape and uniform volume and is convenient to handle. do.

Another object of the present invention is to provide a method for easily manufacturing the wax pattern mold, and further aims to provide a wax pattern mold and a pin body suitable for manufacturing the wax pattern mold.

[Means for Solving the Problems] The wax pattern mold for lost wax casting of the present invention, which has been made to achieve the above object, has an upper half of a conical body having a small trapezoidal head; A plurality of pin bodies whose lower half is a cylindrical body,
a lower mold having a plurality of through holes through which the cylindrical bodies of the plurality of pin bodies penetrate in the upper surface direction; and a bottomed hole corresponding to the plurality of through holes of the lower mold and into which the conical body is inserted. and an upper mold having.

Further, in the above-mentioned mold, the rubber material of the upper mold is inserted into the annular engagement recess formed at the lower peripheral edge of the platform head of the pin body from above the outside of the bottomed hole of the upper mold. The rubber material of the lower die is inserted into the annular engagement recess formed on the upper periphery of the flange provided at the lower end of the pin body from the external lower side of the through hole of the lower die. It is preferable that each of them has an engaging convex portion that bites into engagement.

Next, the manufacturing method of a wax pattern mold for lost wax casting involves embedding a main model and a sprue forming metal fitting between two pieces of rubber material, and embedding the main model in the thickness direction of the rubber material around the main model. Embed multiple pin bodies shorter than the thickness so that their lower ends are exposed from the rubber material, then fit them into the formwork, and press the top and bottom of the formwork with presser plates to press the pin bodies inside the formwork. The rubber material is vulcanized under heat and pressure to form a rubber mold, then the plurality of pin bodies are extracted from the rubber mold, and the rubber mold is cut with a cutter along the central horizontal axis of the main mold. By doing so, the rubber mold is separated into an upper mold and a lower mold, and the main mold and the sprue forming metal fitting are taken out from between the separated upper mold and the lower mold, and then the plurality of pin bodies are removed. The lower end of the cylindrical body is aligned with the bottom surface of the lower mold, and the conical bodies of the plurality of pin bodies 13 are projected onto the mating surface with the upper mold, and the plurality of pin bodies are inserted into the through holes of the lower mold. The upper mold and the lower mold are integrated by fitting the plurality of protruding conical bodies into the plurality of bottomed holes of the upper mold.

Further, in the above manufacturing method, it is preferable that the conical body and the cylindrical body of the pin body each have an engagement recess formed into which the rubber material bites.

In addition, in the above manufacturing method, a plurality of pin bodies with locking holes extending upward from the lower end face are fitted into a plurality of support shaft bodies implanted at predetermined positions at the bottom of the formwork, and the pin bodies are installed vertically. It's good to do that.

Next, the pin body used in the wax pattern mold for lost wax casting has a cylindrical lower part that fits into the through hole of the lower mold, and a small trapezoidal head that fits into the bottomed hole of the upper mold. The present invention is characterized in that the conical body and the cylindrical body have engaging recesses into which the rubber members of the upper mold and the lower mold bite, respectively, on the outer peripheries of the conical body and the cylindrical body.

Further, it is also preferable that a locking hole is formed from the lower end of the pin body toward the inside of the pin body.

[Function] a The wax pattern mold has a plurality of cylindrical pin bodies fixed to the through holes of the lower mold, and the conical bodies of the pin bodies are fitted into the bottomed holes of the upper mold. The combination of the upper mold and the lower mold can be performed accurately.

b. In the wax pattern mold, the engagement protrusion of the rubber material of the upper mold is inserted into the annular engagement recess formed from the outside of the bottomed hole of the upper mold to the lower peripheral edge of the platform head of the pin body. The ring-shaped engagement recess formed at the upper periphery of the flange provided at the lower end of the pin body is inserted into the ring-shaped engagement recess formed at the upper periphery of the flange provided at the lower end of the pin body from the outside lower part of the through hole of the lower die.
Since the engaging convex portion of the rubber material of the lower mold bites and engages, the combination of the upper mold and the lower mold is not only accurate, but also there is no wobbling of the mating surfaces of the upper mold and the lower mold. Accurately hold the cavity formed by the main model.

c. When manufacturing wax pattern molds, the mating surfaces of the upper mold and lower mold are held accurately by engagement with the pin body, so 2.
The main mold and multiple pin bodies were embedded between sheets of rubber material, heated and vulcanized under pressure in a mold to form a rubber mold, and then the multiple pin bodies were extracted from the rubber mold. The rubber mold can be cut with a cutter along the central horizontal axis of the main mold, and the zigzag cutting of the prior art is not necessary, making the cutting extremely simple and efficient. Then, a wax pattern mold is obtained by combining the pin body with the upper mold and lower mold thus formed. Note that almost the same effect can be obtained even if a pin body without an engaging recess is used.

d When using a natural rubber sheet, the pin body with a locking hole formed from the lower end of the pin body toward the inside of the pin body can be fitted and erected onto the support shaft implanted in the formwork. Can be used to form wax patterns.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of an upper mold and a lower mold of a wax pattern mold according to an embodiment of the present invention, FIG. 2 is a sectional view of the upper mold and lower mold combined, and FIG.
The figure is a partially enlarged view of FIG. 2, and FIG. 4 is an enlarged front view of the pin.

An upper mold 11 and a lower mold 1 of a wax pattern mold (rubber mold) for casting lost wax made of silicone rubber material shown by symbol 10 in FIGS. 1 and 2.
2, and 13 is a plurality of pin bodies disposed between the upper mold 11 and the lower mold 12. Concave groove-shaped mold parts 15 and 16 that form a cavity 14 corresponding to the main mold are formed on the mating surfaces 11a and 12a of the upper mold 11 and the lower mold 12 (see FIG. 2), and the mold parts of the lower mold 12 Around the pin body 16, there are a plurality of through holes 17 for arranging the pin bodies 13, each having a shape closely corresponding to the outer shape of the lower half of the pin body 13.
is open. The upper mold 11 also has a plurality of pin bodies 13 arranged in a shape that corresponds to the through hole 17 of the lower mold 12 and closely corresponds to the outer shape of the upper half of the pin body 13 when the upper mold 11 and the lower mold 12 are matched. A bottomed hole 18 for installation is formed.

The pin body 13 is made of metal, and as shown in FIG. 3, the lower half is formed into a cylindrical body 13a, the upper half is formed into a conical body 13b having a small trapezoidal head 13d, and the lower end A flange portion 24 is provided at 13c. At the lower peripheral edge of the platform head 13d, there is an upper mold 1
An annular engagement recess 2 into which the rubber material of 1 bites and engages.
5, an annular engagement recess 23 into which the rubber material of the lower die 12 bites and engages is provided on the upper peripheral edge of the flange 24 of the lower end surface 13c.

In this way, the upper mold 11 has the above-mentioned bottomed hole 1.
From the outside of 8, the engagement convex portion 21 in which a rubber material bites into and engages the engagement concave portion 25 of the pin body 13, and the lower mold 12
From below the outside of the through hole 17, insert the pin body 1.
Engagement protrusions 20 into which a rubber material bites and engages are formed in the engagement recesses 23 of No. 3, respectively.

The pin body 13 has its lower end 13c aligned with the bottom surface 12b of the lower mold 12, and its cylindrical body 13a is attached to the lower mold 12.
while fitting into the through hole 17 of the cone 1
3b is made to protrude above the mating surface 12a of the lower die 12. In this way, the engagement recess 23 of the cylindrical body 13a
The engagement convex portion 20 of the lower mold bites into the pin body 13, and the conical body 13b of the pin body 13 is fixed to the lower mold 12. and,
When the upper mold 11 is placed over the lower mold 12, the cone 13b of the pin body 13 fits into the bottomed hole 18 of the upper mold 11, and the upper mold 11 is engaged with the engagement recess 25 of the cone 13b. The mating convex portion 21 bites in, and the upper mold 11 and the lower mold 12 are joined together.

Note that 26 in FIG. 4 is a locking hole provided inside the cylindrical body 13a, which is not normally provided.
The case where it is provided will be described in detail in the description of other embodiments in FIG.

Next, a method for manufacturing the wax pattern mold 10 will be described.

As shown in FIG. 5, two silicone rubber sheets 31, 31 are prepared, and the main mold 1 is embedded between these silicone rubber sheets 31, 31,
A conical sprue forming metal fitting 35 is embedded, and a plurality of pin bodies 13 are further embedded. The silicone rubber sheets 31, 31 used here are clay-like and can be easily plastically deformed with fingers at room temperature.
Then, use your hands and fingers to shape it so that it fits into the mold 30 shown in FIG.

Incidentally, when embedding the main mold 1 between the two silicone rubber sheets 31, 31, the outer surface of the main mold 1 may be wrapped with a separate small silicone rubber. In this case, the silicone rubber that directly wraps the main model 1 and the silicone rubber sheets 31, 31 may be of different types.

Then, as shown in FIG. 6, the rubber sheets 31, 31 shown in FIG.
The upper and lower sides of the formwork 30 are held down by presser plates 34, 34 made of metal such as aluminum, and the two presser plates 34, 34 are pressurized and heated to form the formwork 30.
The rubber sheets 31, 31 in 0 are vulcanized under heat and pressure. FIG. 7 shows the holding plates 34, 34 and the formwork 3.
0 is removed and the completed rubber mold 10' is shown.
The main mold 1 is embedded inside the main mold 1, and the lower ends 13c of the plurality of pin bodies 13 are exposed on the bottom surface of the rubber mold 10', and the tips 13d of the pin bodies 13 are connected to the main mold 1.
It is recessed to be higher. Next, as shown in FIG. 8, a plurality of pin bodies 13 are extracted from the rubber mold 10', and the pin bodies 13 are traversed from the side position A of the rubber mold 10' through the holes 32 of the plurality of pin bodies 13, and the main prototype is By cutting the central horizontal axis of 1, the rubber mold 10' is separated into an upper mold 11 and a lower mold 12. At this time, since the lower end 13c of the pin 13 is exposed on the bottom surface of the rubber mold 10', the upper mold 11 and the lower mold 12 are cut using this as a guide, that is, with the exposed side of the pin as the lower mold side. Then, the main mold 1 and the sprue forming metal fittings 35 are taken out from between the upper mold 11 and the lower mold 12, and the upper mold 11 and the lower mold 12 are completed.

In this way, the plurality of pin bodies 13 are inserted into the lower mold 12 and the upper mold 11 from the bottom surface 12b of the lower mold 12, following the loopholes 32 of the plurality of pin bodies 13 consecutively arranged in the upper mold 11. , the aforementioned wax pattern mold 10 shown in FIG. 2 is completed.

FIG. 9 shows another method of manufacturing a wax pattern mold, in which a plurality of pin bodies 13 are set in advance on the mold side. That is, in this manufacturing method, the rubber sheets 31, 31
is particularly effective in the case of natural raw rubber. This is because the silicone rubber sheet is clay-like and can be pierced with the pin body 13, but this is difficult to do with natural raw rubber.

In order to support the pin body 13 at a predetermined position on the presser plate 34 at the bottom of the formwork 30, a plurality of hollow pin bodies 13 are fitted and erected onto the plurality of implanted support shaft bodies 34a. , sandwiched between two silicone rubber sheets 31, 31 in the formwork 30, and a plurality of pin bodies 1
Position the main model 1 between the areas surrounded by 3. The rubber is then vulcanized under pressure and heat. The following steps are carried out in the same manner as in the above-mentioned manufacturing method.

In addition, regarding the cutting of the completed main mold 1 described above, the pin body 13 and its pin body 13
The mating surface between the upper mold 11 and the lower mold 12 is secured by biting the rubber material against the upper mold 1.
When cutting and separating the mold 1 and the lower mold 12, there is no need for zigzag cutting to ensure a mating surface between the upper mold 11 and the lower mold 12 as in the conventional manufacturing method, and it is necessary to cut in a straight line. good. However, once you reach the vicinity of the cavity where the main model 1 is embedded, you will need to make some digging and swing the scalpel as appropriate while considering the ease of removing the wax pattern, so in reality there may be some unevenness in that area. This will be the cut surface. However, unlike the conventional method, it is not necessary to form the entire inner surface of the mold into an uneven surface for mold matching.

[Effects of the Invention] The present invention has the following effects.

a. When using a wax pattern mold, there is no need to tighten the upper and lower molds using a special method. Therefore, the assembly operation is extremely simple and efficient.

b When cutting the upper mold and lower mold in the production of wax pattern molds, the alignment of the joining surfaces of both is ensured by connecting the pin body to the upper mold and lower mold, so the central horizontal axis of the main mold Just cut according to the instructions, and do not require the skill and experience required in the past.

c Because the joint surfaces of the upper and lower molds always match,
There is no wobbling in the cavity formed by the main mold, and there is no loss in the cast product.

d The upper mold, lower mold, and pin body are integrated, so they can be easily organized and stored.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an upper mold and a lower mold of a wax pattern mold according to an embodiment of the present invention, FIG. 2 is a sectional view of the upper mold and lower mold combined, and FIG.
The figure is a partially enlarged view of Fig. 2, Fig. 4 is an enlarged front view of the pin, Figs. FIGS. 10A to 10J are explanatory views of a conventional method of manufacturing a wax pattern mold for lost wax casting. 1 ~ Main model, 10 ~ Wax pattern mold,
11-upper mold, 12-lower mold, 13-pin body, 13a
~ Cylindrical body, 13b ~ Conical body, 13c ~ Lower end, 13
d~Platelet head, 17~Through hole, 18~Bottomed hole, 2
0~Engagement convex part, 21~Engagement convex part, 23~Engagement concave part, 24~Flange, 25~Engagement concave part, 26~Latching hole, 30~Mold part, 34~Press plate, 34a~Support shaft Body, 35~ sprue forming metal fittings.

Claims (1)

[Scope of Claims] 1. A plurality of pin bodies 13 whose upper half is a conical body 13b having a small trapezoidal head 13d and whose lower half is a cylindrical body 13a, and the plurality of pin bodies 13
a lower mold 12 having a plurality of through holes 17 through which the cylindrical body 13a passes in the upper surface direction;
2, corresponding to the plurality of through holes 17 of the conical body 1.
an upper mold 11 having a bottomed hole 18 into which the mold 3b is inserted;
A wax pattern mold for lost wax casting, characterized by comprising: 2 From above the outside of the bottomed hole 18 of the upper mold 11,
The engagement convex portion 21 of the upper die 11 is inserted into the annular engagement recess 25 formed on the lower peripheral edge of the platform head 13d of the pin body 13, and the engagement convex portion 21 is engaged with the rubber material of the upper die 11. An engagement in which the rubber material of the lower die 12 bites into and engages an annular engagement recess 23 formed at the upper peripheral edge of a flange 24 provided at the lower end 13c of the pin body 13 from the outside of the through hole 17 from below. Convex portion 20
A wax pattern mold for lost wax casting according to claim 1, each comprising: 3. Embed the main mold 1 and the sprue forming metal fitting 35 between two pieces of rubber material, and insert a plurality of pin bodies 13 shorter than the thickness of the rubber material around the main mold 1 in the thickness direction of the rubber material at its lower end. 13c is embedded so as to be exposed from the rubber material, and then placed in the formwork 30, and the top and bottom of the formwork 30 are pressed with the press plates 34 to heat and heat the rubber material in the formwork 30. A rubber mold is formed by vulcanization under pressure, and then the plurality of pin bodies 13 are extracted from the rubber mold, and the rubber mold is cut along the central horizontal axis of the main mold 1 with a cutter. is separated into an upper mold 11 and a lower mold 12, and the separated upper mold 11 and lower mold 12 are separated.
From between the main mold 1 and the sprue forming metal fitting 35
and then remove the plurality of pin bodies 13.
The lower end 13c of the cylindrical body 13a is aligned with the bottom surface of the lower mold 12, and the conical body 1 of the plurality of pin bodies 13 is
3b protrudes onto the mating surface with the upper mold 11, and the plurality of pin bodies 13 are fitted into the through holes 17 of the lower mold 12, and the plurality of protruding conical bodies 13b are fitted into the through holes 17 of the lower mold 12. Multiple bottomed holes 1 of mold 11
8, and the upper mold 11 and the lower mold 12 are integrated. 4 Conical body 13b and cylindrical body 1 of the pin body 13
4. The method of manufacturing a wax pattern mold for lost wax casting according to claim 3, wherein a pin body is used in which engaging recesses 25 and 23 into which the rubber material bites are formed in the pin body. 5. A claim in which a plurality of pin bodies 13 having locking holes 26 extending above the lower end 13c are fitted and erected on a plurality of support shaft bodies 34a implanted at predetermined positions at the bottom of the formwork. 5. The method for manufacturing a wax pattern mold for lost wax casting according to 3 or 4. 6 A lower part that fits into the through hole 17 of the lower mold 12 is a cylindrical body 13a, a conical body 13b having a small trapezoidal head 13d that fits into the bottomed hole 18 of the upper mold 11, and the mold conical body 13b and a wax pattern molding mold for lost wax casting, characterized in that engagement recesses 25 and 23 into which the rubber materials of the upper mold 11 and the lower mold 12 bite are formed on the outer periphery of the cylindrical body 13a, respectively, and the same. Pin bodies used in manufacturing. 7 From the lower end 13c of the pin body 13 to the pin body 13
Claim 6: A locking hole 26 is formed toward the inside.
A wax pattern mold for casting lost wax as described in , and a pin body used for manufacturing the same.