WO2021144947A1 - Injection molding device and method - Google Patents

Abstract

Disclosed is an injection molding device 10 that includes: a wax tank 21 that stores wax; an injection part 24 connected to the wax tank; a suction part 42 capable of suctioning air; and a rubber mold 50 including an injection port 52 capable of contacting the injection part 24, a suction port 53 capable of contacting the suction part 42, and a cavity 51 connected to the injection port 52 and the suction port 53. The wax in the wax tank 21 is injected into the rubber mold 50 from the injection part 24 by the pressure in the wax tank 21. The cavity 51 and the suction port 53 allow the passage of air, and are connected via a wax blocking part 54 that blocks the passage of the wax.　

Description

Injection molding equipment and method

The present application relates to an injection molding apparatus and an injection molding method for wax used for lost wax casting.

Ornaments, accessories, jewelry, etc. that mainly use precious metals are small, complicated, and have more precise shapes. There is a desire to mass-produce such products, and the lost wax precision casting method has been developed in this industry. Of course, it can also be applied to the manufacture of precision industrial parts other than the above.

Lost wax precision casting in the jewelry manufacturing industry has the following steps.
The first process is the process of manufacturing the prototype.
The second process is the process of manufacturing a rubber mold that has a cavity with the same shape as the prototype.
The third process is the process of injecting wax dissolved in a rubber mold and taking it out to manufacture a wax mold with the same shape as the prototype. Generally, a large number of wax molds are manufactured by repeating the third step.
In the fourth step, a large number of wax molds manufactured in the third step are attached in a tree shape while melting the end of the wax mold around the wax rod, and this is mounted in a tubular heat-resistant container and plaster is poured. The process of making a plaster mold.
In the fifth step, an electric furnace, a gas furnace, or the like is used to dissolve and wash away the wax inside the gypsum mold at low temperature, completely burn the wax adhering to the inside of the cavity at medium temperature, and raise the temperature further to make the gypsum mold. A firing process in which gypsum is strong enough to withstand the impact of pouring noble metal, and then the temperature is lowered to a level suitable for pouring noble metal.
The sixth process is a casting process in which precious metal is poured into a plaster mold that has many cavities similar to the prototype.
In the seventh step, when the precious metal is solidified, the plaster mold is rapidly cooled with water to break the plaster into pieces, take out the dendritic precious metal, cut off the excess part, and polish the precious metal with the same shape as the prototype. Process.

The method for manufacturing the rubber mold in the second step will be described with reference to FIG. In the second step, a mold (not shown) having a size corresponding to the size of the rubber mold 50 to be created, the prototype 1, and the parts 2 (runner 2a and sprue 2b) are used. Close the bottom of the mold with a plate, put the material before vulcanization of silicone rubber in the lower half, place the part 2 bonded to the prototype 1 on it, and then put the material before vulcanization in the upper half. Put it in, cover the upper part of the frame with a plate, raise the temperature while pressing, and vulcanize. A two-component solidified silicone rubber may be used instead of the vulcanizable rubber.

When the silicone rubber has hardened and has the original elasticity of the rubber, the rubber mold 50 is taken out from the frame to form a notch 56, and the prototype 1 and the part 2 adhered to the prototype 1 are taken out, and the upper rubber mold 50a is taken out. And the lower rubber mold 50b. As a result, a rubber mold 50 having a cavity 51 and an injection port 52 having the same shape as the prototype 1 and the component 2 inside can be obtained. By making such a notch 56 in the entire separation surface, when the upper and lower rubber molds 50a and 50b are combined, they can be accurately aligned and the internal cavity shape can be accurately reproduced.

Such a notch 56 also has an effect of facilitating evacuation and sealing of the pressurized wax when injecting wax into the rubber mold 50 to create a wax mold. When the wax mold is taken out from the rubber mold 50, if the upper rubber mold 50a is separated from the mating surface (cut) 3c and then taken out while deforming the lower rubber mold 50b, even if the wax mold has a complicated shape, it is taken out. , Can be easily taken out without breaking. In some cases, the inside of the rubber mold may be divided into several parts or a core may be inserted.

Since the prototype has various sizes, the size and thickness of the rubber mold will change accordingly. In addition, the hardness of the rubber is often changed according to the durability of the rubber mold and the difficulty of removing the wax mold from the inside of the rubber mold.

FIG. 2 shows a conceptual diagram of the injection molding apparatus 10 used in the third step. The injection molding device 10 has a main body device 20, a clamp unit 30, and a rubber mold 50. The main body device 20 has a wax tank 21 for storing wax in a pressurized state, a vacuum tank 22 connected to a vacuum pump, and an injection unit 24.

The clamp unit 30 is for clamping the rubber mold 50, and some have a function of pressing the injection port 52 of the rubber mold 50 against the injection portion 24.

The injection unit 24 can be selectively connected to the wax tank 21 and the vacuum tank 22 by the switch 25, and has an air suction function for sucking (evacuating) the air in the cavity 51 and a wax for injecting wax into the cavity 51. It has two functions, an injection function.

The injection molding device 10 clamps the rubber mold 50 with the clamp unit 30, presses the rubber mold 50 against the injection portion 24, sucks the air in the cavity 51 from the injection portion 24, and injects wax from the injection portion 24 into the cavity 51. ..

Normally, the ultimate vacuum of a vacuum pump that performs suction is about -100 kpa to -95 kpa. The perfect vacuum is theoretically -101.325 kpa. Therefore, even if the air in the cavity 51 is sucked, a few percent of the air always remains in the cavity as residual air.

Compared to a resin injection molding device that injects molten resin into a mold at high pressure, an injection molding device that injects wax into a rubber mold, such as in jewelry manufacturing, has a much lower injection pressure, so this residual air is completely removed. Can't be crushed. Further, in injection molding using a mold, since a certain amount of resin can be injected with a screw or a plunger, it is possible to provide an air bleeding mechanism in the mold. On the other hand, in injection molding using a rubber mold, since wax is injected under constant pressure conditions, an air bleeding mechanism cannot be provided. (If an air bleeding mechanism is provided, wax will enter the air bleeding mechanism and clog it.)

This causes various problems in the wax mold making in the third process. The rubber mold shown in FIG. 1 has the simplest design, but if the wax is immediately injected after vacuuming the inside of the cavity, the wax will flow from the sprue through the sprue to both ends of the ring, and the hot water will flow. At the farthest point from the road, the waxes rejoin. Then, the above-mentioned several percent of the air is collected at this confluence and condensed to a pressure that is in equilibrium with the injection pressure.

The condensed air causes bubbles or wrinkles, and the wax mold becomes defective. In particular, in the case of a ring-shaped object as shown in FIG. 1, for example, a ring, there is often a finely designed decoration at this confluence. For example, if there is a protrusion at the confluence, the protrusion will curl up or wax will not enter to the tip.

It is theoretically impossible to manufacture a wax mold that completely adheres to the hollow wall, whether it is a simple design or a complicated design.

Currently, the most popular way to deal with this problem is to apply baby powder or something similar to the rubber mold. By doing so, since a very small gap is generated in the notch 56 of the rubber mold, it can be expected that the residual air in the cavity is discharged at the time of wax injection.

However, if the amount of powder applied is increased, the effect of discharging residual air is enhanced, but if it adheres to the surface of the wax mold, the surface becomes rough, and conversely, if the amount of powder applied is suppressed, the effect of discharging residual air is small. Become. Further, since the degree of vacuum of the rubber mold 50 is lowered due to the leakage from the slight gap of the notch 56 formed by the powder, it does not solve the essential problem.

As mentioned above, the problem of residual air cannot be sufficiently solved only by the method using powder. Especially as the design becomes more complex, the problem of residual air becomes even greater. Therefore, I managed to make a wax mold while shifting the position of action of the clamping force, changing the injection pressure, changing the temperature of the wax, etc., and the person in charge every time a new design is made. The current situation is that the hardships are constant.

International Publication No. 2017/06870

As the wax is injected, the residual air in the cavity is condensed and the pressure gradually increases. If this residual air can be removed, the cavity will be filled with wax while maintaining a constant vacuum. be able to. As a result, most of the above-mentioned problems are solved, and it becomes possible to manufacture a rubber mold having a more difficult design. Furthermore, the evolution of ornamental design is also promoted. One object of the present invention is to reduce the residual air in the cavity as much as possible. Another object of the present invention is to enable more faithful wax mold production due to the shape of the cavity. Another object of the present invention is to enable the production of wax molds having a more precise or fine shape.

In this application, a wax tank for storing wax and
The injection part connected to the wax tank and
A suction part that can suck air and
It has an injection port capable of contacting the injection portion, a suction port capable of contacting the suction portion, and a rubber mold having a cavity connected to the injection port and the suction port.
An injection molding device that injects wax from the wax tank from the injection portion into the rubber mold cavity by the pressure in the wax tank.
An injection molding device is disclosed in which the cavity and the suction port are connected via a wax blocking portion that allows the passage of air and blocks the passage of wax.

In the above invention, it is preferable that the cavity and the wax blocking portion are connected by a plurality of connecting passages.

In the above invention, it is preferable that the rubber mold has a notch passing through the wax blocking portion and / or the connecting passage.

In the above invention, it is preferable that the vertical or horizontal dimension of the cross section of the wax blocking portion is three times or less the thickness of the wax film formed on the wax blocking portion when the wax is injected.

In the above invention, it is preferable that the wax blocking portion has a plurality of passages whose cross-sectional vertical or horizontal dimensions are three times or less the thickness of the wax film formed on the wax blocking portion when wax is injected.

The present application is an injection molding method using any of the above injection molding devices.
The first step of sucking the air inside the rubber mold from the suction part,
It has a second step of injecting wax from the injection portion into the rubber mold.
An injection molding method is disclosed in which the second step is performed during the execution of the first step.

The manufacturing method of the conventional rubber mold 50 is shown. The conventional injection molding apparatus 10 is shown. An injection molding apparatus 10 according to an embodiment of the present invention is shown. An exemplary suction device 40 is shown. An exemplary rubber mold 50 is shown. An exemplary rubber mold 50 is shown. An exemplary method for manufacturing the rubber mold 50 is shown. An exemplary shape of the member 65b corresponding to the wax blocking portion 54 is shown. An exemplary wax injection method using the injection molding apparatus 10 is shown.

FIG. 3 shows an injection molding apparatus 10 according to an embodiment of the present invention. The injection molding device 10 includes a main body device 20, a clamp unit 30, a suction device 40, and a rubber mold 50.

The main body device 20 has a tank 23 having a wax tank 21 and a vacuum tank 22, an injection unit (injection nozzle) 24, a first switch 25a, and a second switch 25b.

The molten wax is stored in the wax tank 21 in a pressurized state. The main body device 20 may have a pressurizing source P such as a compressor connected to the wax tank 21 and a vacuum source V such as a vacuum pump connected to the vacuum tank 22. The pressurizing source P is preferably a constant pressure pressurizing source, and particularly preferably a constant pressure air pressure source. The wax tank 21 and the vacuum tank 22 may be arranged concentrically, and a band heater 23b for warming the entire tank 23 to an appropriate temperature and constantly dissolving the wax may be arranged around the tank 23.

The wax tank 21 and the vacuum tank 22 are connected to the injection unit 24 via the in- device pipes 21L and 22L and the first switch 25a. The first switch 25a is
-A state in which the injection unit 24 is separated from both the wax tank 21 and the vacuum tank 22 (state 1).
-A state in which the injection unit 24 is connected only to the vacuum chamber 22 (state 2), or
-A state in which the injection unit 24 is connected only to the wax tank 21 (state 3).
It is possible to switch between the three states of.

The vacuum tank 22 is further connected to the external pipe 44 via the in-device pipe 22L and the second switch 25b. The second switch 25b may be an open / closed (on / off) switch.

The clamp unit 30 has a table 31, a clamp force generator 32 such as a pneumatic cylinder, and a clamp plate 33, and the rubber mold 50 (and) between the table 31 and the clamp plate 33 by the force of the clamp force generator 32. Clamp the suction device 40). The clamp unit 30 may further have a pressing mechanism 34 for aligning the rubber mold 50 with the axis of the injection portion 24 and / or pressing the rubber mold 50 against the injection portion 24.

The suction device 40 is a device for sucking air from the rubber mold 50. FIG. 4 shows an exemplary suction device 40. The suction device 40 of this example has a plate-like shape having an upper surface 41 on which the rubber mold 50 can be placed and a suction portion (suction port) 42 capable of contacting the suction port 53 of the rubber mold 50 mounted on the upper surface 41. It is a member. The suction unit 42 can be connected to the vacuum tank 22 via the internal pipe 43, the external pipe 44, and the device internal pipe 22L. The suction device 40 can be formed of acrylic resin or the like, and the suction portion 42, the internal piping 43, or the like can be formed by drilling or the like. The internal pipe 43, the external pipe 44, and the device internal pipe 22L can be connected by a joint (not shown) or the like.

Figures 5 and 6 show an exemplary rubber mold 50. The rubber mold 50 has a cavity 51, an injection port 52, a suction port 53, and a wax blocking portion 54. The cavity 51 may have a shape corresponding to the prototype 1. The cavity 51 is connected to the injection port 52 and the wax blocking portion 54, and the wax blocking portion 54 is connected to the suction port 53. The injection port 52 can come into contact with the injection portion 24, and the suction port 53 can come into contact with the suction portion 42.

The wax blocking unit 54 has a function of blocking the passage of wax while allowing the passage of air. An exemplary mechanism and structure by which the wax blocking section 54 achieves this function is as follows.

The temperature of wax used for manufacturing ornaments such as jewelry is usually around 75 ° C and is injected into the rubber mold 50, but the temperature of the rubber mold 50 is close to room temperature (20-40 ° C). The wax gradually hardens from about 65 ° C and solidifies at about 60 ° C. At some temperature, the liquid does not suddenly turn into a solid. Wax has the property of poor heat conduction.

When the injected wax comes into contact with the inner wall of the rubber mold 50, the part near the inner wall is immediately cooled to form a thin film. Since the film has poor thermal conductivity, the temperature of the wax flowing inside the film does not drop so much, and the wax fills every part inside the rubber mold 50 while forming the film one after another. Even so, the temperature of the wax flowing inside the rubber mold 50 gradually decreases, so it is necessary to increase the injection pressure in order to quickly fill the rubber mold 50 to a long distance.

Since this film is formed around the entire circumference perpendicular to the direction in which the wax flows, if the width of the passage is less than twice the thickness of this film (film thickness T), the wax cannot pass continuously. For example, if the film thickness T is about 0.1 mm and the width of the passage is about 0.2 mm, the wax cannot pass continuously and hardens immediately after passing a short distance. The wax blocking unit 54 of the present invention can achieve the above function by using this principle. However, this film is considered to be very thin because high-temperature wax passes one after another near the sprue, but the farther from the sprue, the lower the temperature of the passing wax and the smaller the flow rate, so the film tends to become thicker. It is in.

For example, if the wax blocking portion 54 is a rectangle with a cross section A × B and a length L, the above function is achieved by setting the dimension of A or B (vertical or horizontal dimension) to about twice the film thickness T. can. The length L may be set to a sufficient length so as to prevent the passage of wax in consideration of the cross section A × B. By forming the wax blocking portion 54 in a plurality of flow paths, it becomes easy to secure a sufficient air flow rate for suction of the cavity 51. With such a design, the above function can be achieved with a wax blocking portion 54 having a sufficiently small size.

The cross-sectional shape of the wax blocking portion 54 is arbitrary, such as a circular shape, an elliptical shape, or an annular shape. That is, if the passage width is about twice that of the coating film, the wax cannot continuously pass through even if the cross section is not rectangular. Any shape may be used as long as it is easy to manufacture, the solidified wax can be easily taken out, and the rubber mold can be used continuously.

It is preferable that the wax blocking portion 54 and the cavity 51 are connected by a narrow connecting passage 55. The connection passage 55 is preferably connected to the cavity 51 at a portion where residual air tends to collect when the wax is injected (for example, a portion where the wax finally reaches, a portion where the wax merges). There is not always one place where residual air tends to collect. Therefore, it is preferable to provide a plurality of connection passages 55 and / or to connect to the cavity 51 at a plurality of locations.

In the connection portion between the connection passage 55 and the cavity 51, since it is necessary to cut the unevenness after casting the precious metal to finish the cut surface, it is often impossible to connect the connection passage 55 to an important part of the design. For example, in the case of a ring such as a ring, since decorations and characters are designed on the outer circumference, the connection passage 55 cannot be connected to this portion. In such a case, as shown in FIG. 6, it is possible to connect to the inner circumference of the ring through a three-dimensional connection passage 55.

The rubber mold 50 has a notch 56. The notch 56 facilitates removal of the solidified wax mold from the cavity 51. The wax can also penetrate into the connecting passage 55, the wax blocking portion 54, the suction port 53, and the like and solidify. Therefore, it is desirable to further form a notch 56 that passes through the connecting passage 55, the wax blocking portion 54 and / or the suction port 53 (or reaches the connecting passage 55, the wax blocking portion 54 and / or the suction port 53). As a result, the wax solidified in the connecting passage 55, the wax blocking portion 54 and / or the suction port 53 can be easily removed. In FIGS. 5 and 6, for simplicity, a single notch 56 (mainly for the purpose of taking out the wax mold) for separating the rubber mold 50 into the upper rubber mold 50a and the lower rubber mold 50b is shown. One or more notches 56 may be additionally formed to achieve the objective. All or part of the notch 56 is a notch that completely separates the rubber mold 50, and all or part of the notch 56 is a notch that partially cuts the rubber mold 50 but does not completely separate it. obtain.

FIG. 7 shows an exemplary method for manufacturing the rubber mold 50. Members 64a to 64c corresponding to the prototype 1, the runner 2a, and the sprue 2b are arranged inside the mold 63 guided by the guide pin 62 provided on the lower frame 61, and further, the suction port 53 and the wax blocking portion 54. And the members 65a to 65c corresponding to the connection passage 55 are arranged as shown in FIG. Reference numeral 65d is a screw for fixing the members 65a and 65b. At this time, the member 65a corresponding to the suction port 53 is guided by the guide hole provided in the lower frame 61 so that the position can be specified. Insert the pre-vulcanization rubber 66 into the hatched part in the figure without any gaps, cover it with the upper lid 67 so that it rises slightly above the mold 63, and press it in the direction of arrow 68. It is discharged to 69. By heating in such a pressed state at an appropriate temperature for an appropriate time, the elastic rubber is vulcanized.

After vulcanization, the rubber mold 50 can be manufactured by taking out the rubber mold 50 from the mold and taking out various constituent materials 64a to 64c and 65a to 65d put inside while making an appropriate notch 56. can.

FIG. 8 shows an exemplary shape of the member 65b corresponding to the wax blocking portion 54.

The member 65b of FIG. 8A has a plate thickness of B, and a plurality of rectangular openings (indicated by hatched portions / width C × length L) are formed at intervals A. The opening can be formed by hollowing out with a laser processing machine or the like. When the rubber mold 50 is manufactured using this member 65b, the hunting portion becomes rubber, and a wax blocking portion 54 having a passage having a plurality of cross sections A × B and a length L is formed.

The dimension A should be about twice or less than the film thickness T. The length L is a length for ensuring that the wax hardens. The smaller the dimension A, the shorter the L may be. However, in order to secure the required air flow, it is necessary to increase the dimension B and / or increase the number of passages.

The member 65b of FIG. 8B has a plate shape of thickness A × width B, and the member 65b of FIG. 8C has a ring shape of thickness A × circumference B. In this case, the wax blocking portion 54 is a passage having a cross section A × B and a length L. The dimension A needs to be sufficiently small (for example, about 0.2 to 0.3 mm) to effectively block the passage of wax, and the width B or the circumference B is required to secure a sufficient air flow. Needs to be large.

In the wax blocking portion 54 having an arbitrary cross section, the vertical or horizontal dimension (dimension A) of the cross section is preferably 3 times or less, more preferably 2.5 times or less, and 2.1 times or less the film thickness T. Is particularly preferable.

FIG. 9 shows an exemplary wax injection method using the injection molding apparatus 10. In step S1, the first switch 25a is in state 1, and the injection unit 24 is separated from both the wax tank 21 and the vacuum tank 22. Further, the second switch 25b is turned off. In step S2, the suction port 53 and the suction portion 42 are aligned and the rubber mold 50 is laminated on the upper surface 41 of the suction device 40. In step S3, the laminated body (suction device 40 and the rubber mold 50) is placed on the table 31. It will be placed. In step S4, the clamping force generator 32 clamps the laminate between the table 31 and the clamp plate 33, aligns the injection port 52 of the rubber mold 50 with the injection portion 24, and the pressing mechanism 34 ejects the rubber mold 50. Press against the part 24.

In the following step S5, the second switch 25b is turned on, air suction in the rubber mold 50 from the suction section 42 is started, and in step S6, the first switch 25a is switched to the state 2 and is switched from the injection section 24. Air suction in the rubber mold 50 of the above is started.

After the degree of vacuum in the rubber mold 50 has become sufficiently high in steps S5 and S6, the first switch 25a is switched to the state 3 in step S7, and wax is injected from the injection unit 24 into the rubber mold 50.

After step S7 is executed for a sufficient time to sufficiently fill the cavity 51 with wax, the first switch 25a is switched to the state 1 in step S8, and the second switch 25b is turned off in step S9. Become. That is, the suction from the suction unit 42 continues from step S5 to step S9. In the following step S10, the clamp unit 30 presses the rubber mold 50 and releases the clamp.

In the following step S11, the rubber mold 50 is removed from the clamp unit 30, and the wax mold is taken out from the rubber mold 50 after the wax has solidified.

After that, the process returns to step S2, and steps S2 to S11 are executed using the same or different rubber molds 50. Steps S1 to S11 may be carried out at the same time as appropriate, and / or the order may be changed. For example, steps S5 and S6 and / or steps S8 and S9 may be performed simultaneously or in reverse order.

In the injection molding apparatus 10, wax injection (step S7) into the rubber mold 50 is executed during the continuation of air suction (steps S5 to S9) from the suction unit 42, so that the residual air in the cavity 51 is effective. Can be removed and / or the wax reaches every corner of the cavity 51 and / or the shape of the cavity 51 makes it possible to produce a more faithful wax mold.

Since the injection port 52 and the connection passage 55 are connected to different parts of the cavity 51, the residual air can be effectively sucked. For example, the connection passage 55 and the cavity 51 may be connected at the portion where the wax finally reaches or the portion where the wax merges.

Since the wax blocking portion 54 is arranged between the cavity 51 and the suction port 53, it is possible to prevent the wax intrusion / blockage of the suction portion 42 and the internal piping 43.

The injection molding device and the injection molding device of the above embodiment are examples, and can be appropriately changed within the scope of the claims. For example, in the above embodiment, the injection part 24 shows an injection molding apparatus having two functions of an air suction function and a wax injection function, but the injection part has only a wax injection function and air suction is performed only from the suction part 42. May be configured to do. In that case, the first switch 25a may be an on / off switch for opening and closing the in-device piping 21L, state 1 may be an off state, state 3 may be an off state, and step S6 may be omitted. In the above embodiment, the wax blocking portion 54 having a uniform cross section (A × B) in the length L direction is shown, but the cross section does not necessarily have to be uniform. In addition, the dimensions, shape, arrangement, number, materials, injection molding method procedure, etc. of the injection molding apparatus or its elements can be changed in various ways.

The injection molding apparatus and injection molding method of the present invention can be used in lost wax casting for manufacturing small items such as jewelry and accessories and industrial products. By sucking the residual air that aggregates during wax injection, the production yield of the wax mold is improved and / or it becomes possible to manufacture the wax mold that is faithful to the cavity shape, and / or it is difficult with the prior art. It enables the production of wax molds having fine and / or complex shapes.

1 ... Prototype 2 ... Structure forming member 10 ... Injection molding device 20 ... Main body device 21 ... Wax tank 22 ... Vacuum tank 21L, 22L ... In-device piping 23 ... Tank 24 ... Injection part 25 ... Switch 25a ... First switch 25b ... Second switch 30 ... Clamp unit 31 ... Table 32 ... Clamp force generator 33.・ ・ Clamp plate 34 ・ ・ ・ Pressing mechanism 40 ・ ・ ・ Suction device 41 ・ ・ ・ Top surface 42 ・ ・ ・ Suction part 43 ・ ・ ・ Internal piping 44 ・ ・ ・ External piping 50 ・ ・ ・ Rubber mold 51 ・ ・ ・ Cavity 52 ... Injection port 53 ... Suction port 54 ... Wax blocking part 55 ... Connection passage 56 ... Notch 61 ... Lower frame 62 ... Guide pin 63 ... Mold frame 64a ~ 64c, 65a ~ 65d ... Structure forming member 66 ... Rubber before vulcanization 67 ... Top lid

Claims (6)

1. A wax tank for storing wax and
   The injection part connected to the wax tank and
   A suction part that can suck air and
   It has an injection port capable of contacting the injection portion, a suction port capable of contacting the suction portion, and a rubber mold having a cavity connected to the injection port and the suction port.
   An injection molding device that injects wax from the wax tank from the injection portion into the rubber mold cavity by the pressure in the wax tank.
   An injection molding device in which the cavity and the suction port are connected via a wax blocking portion that allows the passage of air and blocks the passage of wax.
2. The injection molding apparatus according to claim 1, wherein the cavity and the wax blocking portion are connected by a plurality of connecting passages.
3. The injection molding apparatus according to claim 2, wherein the rubber mold has a notch passing through the wax blocking portion and / or the connecting passage.
4. The injection molding apparatus according to any one of claims 1 to 3, wherein the vertical or horizontal dimension of the cross section of the wax blocking portion is 3 times or less the thickness of the wax film formed on the wax blocking portion at the time of wax injection. ..
5. Any one of claims 1 to 3, wherein the wax blocking portion has a plurality of passages having a vertical or horizontal dimension of a cross section of 3 times or less the thickness of a wax film formed on the wax blocking portion when wax is injected. Injection molding equipment.
6. An injection molding method using the injection molding apparatus according to any one of claims 1 to 5.
   The first step of sucking the air inside the rubber mold from the suction part,
   It has a second step of injecting wax from the injection portion into the rubber mold.
   An injection molding method in which the second step is performed during the execution of the first step.

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