JP2000301289A - Production of lost form pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce a lost foam pattern for producing a mold for casting an impeller having complicate shape in a short time without causing any burrs. SOLUTION: This method for manufacturing the mold for casting the impeller, in which the blades are arranged among a main plate and side plates, consists of a process for producing a mold 42 for lost foam pattern based on master molds 10, 12, 14 for the whole shape of impeller, a process for producing a mold for forming a lost foam core based on the master mold 10 for core at the portion corresponding to the cavity among the main plate and the side plates, a process for producing a lost foam core by pouring a first lost foam raw material into the mold for forming the lost foam core, a process for producing the lost foam pattern containing the lost foam core by disposing this lost foam core in the mold for lost foam pattern 4 and pouring a second lost foam raw material, and a process for losing the lost foam core with a means, by which only the first lost foam raw material is selectively lost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a vanishing model for a mold used for producing a mold for casting, for example, an impeller of a turbomachine.

[0002]

2. Description of the Related Art A main plate 100 and a side plate 10 as shown in FIG.
The impeller 106 of the turbomachine provided with a plurality of (three in the drawing) blades 104 inside 2 is manufactured by, for example, an investment casting method. Investment casting is
In this method, a refractory material having fluidity is attached to the periphery of the dissipative male mold, and after drying and solidifying the refractory material, the male mold is eliminated by heating or melting to produce a mold.

That is, in this method, as shown in FIG. 10, a molten metal is poured into a cavity 114 of a mold 112 integrally formed with a core 110 disposed therein and solidified. The core 110 is, as shown in FIG.
The number of divided cores 116 divided into the same number as the number of cores is combined in a disk shape. As shown in FIG. 12, the split core is formed by injecting a slurry from the injection port 122 into the split core mold 120, solidifying and releasing the slurry. And
As shown in FIG. 13, the split cores 116 are combined to form a core 110, which is disposed in a vanishing model mold 130 (FIG. 13A), and wax or the like is injected from the injection port 130a. After injection and solidification, it is released from the mold and disappears.
2 is formed (FIG. 13B). A shell 134 is attached to the outer peripheral surface of the vanishing model 132 (FIG. 13).
(C)) Thereafter, the erasure model 132 is erased to manufacture.

[0004]

However, the above-mentioned investment casting method is suitable for mass production because the mold 130 is used for producing the disappearance model 132, but it is suitable for mass production and small production. In this case, the cost is high. Further, since the hollow portion corresponding to the wing 104 in the core 110 has a three-dimensionally complicated shape, a divided core 116 obtained by dividing the core 110 into the number of wings 104 is manufactured, and these are combined. The core 110 is formed to form a cavity corresponding to the portion of the wing 104, but a complicated split core mold 1 for forming the split core 116 is formed.
Manufacturing the 20 is a time-consuming operation, not only requiring days, but also significantly increasing the manufacturing cost.

The wing 104 of the impeller 106 has a complicated shape, and a cavity for casting the wing 104 is formed between the divided cores. There is a problem that burrs occur in the produced disappearing model 132 due to the influence of the thickness and the shape, and the dimensional accuracy of the final product is reduced.

SUMMARY OF THE INVENTION In view of the above problems, the present invention makes it possible to easily and quickly produce a vanishing mold for a mold for producing a mold for casting an impeller having a complicated shape without generating burrs. It is an object of the present invention to provide a method for manufacturing a disappearing model for a mold that can be used.

[0007]

According to the first aspect of the present invention, there is provided a method of manufacturing a vanishing model for manufacturing a mold for casting an impeller having wings disposed between a main plate and a side plate, A step of preparing a vanishing model mold based on a master mold of the entire shape of the impeller, and removing vanishing cores based on a master mold of a core corresponding to a cavity between the main plate and the side plate. A step of preparing a mold; a step of injecting a first vanishing material into the vanishing core removing mold to produce a vanishing core; placing the vanishing core in the vanishing model mold;
Injecting the disappearing material, and producing a vanishing model including the vanishing core, and a step of vanishing the vanishing core by means for selectively vanishing only the first vanishing material. A method for producing a vanishing model characterized by the following.

Thus, an integral vanishing model having cavities corresponding to the main plate, the side plates, and the wings can be manufactured easily and accurately while preventing generation of burrs. Therefore, by producing a mold using this, an impeller having a complicated shape can be cast with good reproducibility.

According to a second aspect of the present invention, the mold for removing the lost core and / or the mold for the lost model is made of a rubber-like material. It is a manufacturing method. By using a rubber mold,
The removal of the wing portion having a complicated three-dimensional shape is facilitated, the breakage accident can be prevented, and the workability is good, so that the required time can be shortened and the production cost can be suppressed. As a material of the mold for removing the disappearing core and / or the mold for the disappearing model, a transparent material may be used, and an ultraviolet curing resin or wax may be injected to irradiate ultraviolet rays to produce a disappearing model. Thereby, the time for curing can be shortened, and the manufacturing cost can be further suppressed.

According to a third aspect of the present invention, there is provided the method for manufacturing a vanishing model according to the first aspect, wherein the core master mold is manufactured by a rapid model manufacturing method. As a result, a core master mold can be accurately produced in a short time. As a rapid model manufacturing method, there are a selective laser sintering method, a droplet jetting method, a melt deposition method, a stereolithography method, a thin plate laminating method, a solid base hardening method and the like.

According to a fourth aspect of the present invention, there is provided the method for manufacturing a vanishing model according to the first aspect, wherein each master mold of the main plate and the side plate is manufactured by machining. This allows easy and accurate fabrication by directly processing with an automatic control processing machine that operates a tool according to a program (CAM) input in advance using a directly processable material such as urethane resin.

A fifth aspect of the present invention is a method for producing a mold, characterized by producing a mold using the disappearing model produced by the method according to any one of the first to fourth aspects.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. here,
A method of manufacturing a mold vanishing model used for manufacturing a mold for casting an impeller 106 having three blades 104 between a main plate 100 and a side plate 102 as shown in FIG. 9 will be described.

First, as shown in FIG. 1, a core master mold 10 corresponding to a portion sandwiched between the main plate 100 and the side plate 102 is manufactured by a rapid model manufacturing method. The core master mold 10 is manufactured as a female mold having a cavity corresponding to the wing 104. In the present embodiment, an elastomer is used as a material to manufacture by a stereolithography method using a selective laser sintering apparatus which is a kind of a rapid model manufacturing method. This will be described with reference to FIG.

A particulate elastomer material is supplied into the chamber 22 of the selective laser sintering device 20 and, for example, 0.1 mm
The thickness h of the elastomer material layer 24 is formed. Then, a laser beam from a laser light source 26 such as a carbon dioxide laser generator is applied to the elastomer material layer 24 via a mirror 28,
The elastomer material located at the portion irradiated with the laser light is selectively melt-hardened (sintered), and the elastomer flake 30 is formed.
To form Hereinafter, this step is repeated to sequentially laminate the elastomer thin pieces 30 to form a predetermined shape. The irradiation pattern of the laser beam is controlled by a control device having a storage unit in which a shape to be manufactured is stored in advance.

According to this method, a wing 10 having a three-dimensionally complex shape is formed based on data input in advance.
Even with the impeller having the core 4, the core master die 10 can be manufactured with a high degree of shape reproducibility and simple steps. Specifically, the core master mold 10 is
For example, it is formed using nylon containing 40% glass fiber.

On the other hand, the master dies 12 and 14 of the main plate 100 and the side plate 102 are each provided with an automatic control machining machine (NC) for operating a tool in accordance with a program (CAM) input in advance by using a plate-shaped porous resin or the like. (Processing machine). By this method,
The master dies 12 and 14 of the main plate 100 and the side plate 102 can be manufactured in a simple process with a high degree of shape reproducibility based on data input in advance.

Specifically, each master mold 12, 14
For example, a urethane resin having a porosity of 40% (trade name: Truefoam) is cut out to produce a resin having an outer diameter of 300 mmφ. It is desirable to use a porous resin having a porosity of 15% or more so that pores can absorb linear expansion during heating.

Next, the core master mold 1 is placed in a predetermined container.
0, melted rubber is injected into this container, and a core master mold 10 is embedded with rubber as shown in FIG.
After the rubber is cured, the rubber mold is cut along an appropriate cut surface A, and the master mold 10 is removed, thereby producing a disappearing core removing rubber mold 40 having a cavity corresponding to the shape of the core. Since the rubber has elasticity, even when the wing has a three-dimensionally complicated shape, it can be easily deformed, and the mold can be easily removed without breakage.

Similarly, the core master mold 10 is combined between the master molds 12 and 14 of the main plate 100 and the side plate 102 and placed in a container, and molten rubber is injected into the container, and FIG. As shown in the figure, the integrated master dies 10, 12, and 14 are embedded with rubber, and after the rubber is cured, the master dies are cut along an appropriate cut surface B to obtain each master die 1.
The molds 0, 12, and 14 are removed, and a rubber mold 42 for a disappearing model is manufactured.

More specifically, the rubber mold 40 for removing the lost core and the rubber mold 42 for the lost model are made of, for example, silicon rubber (KE13105 manufactured by Shin-Etsu Chemical Co., Ltd.) as a rubber material and left at 70 ° C. for 12 hours. It is made by curing. If the cut surfaces A and B are formed by giving appropriate irregularities, it is possible to facilitate the alignment in the subsequent joining step.

Next, as shown in FIG. 5, a vanishing core 44 having a cavity 44a for a wing portion is formed by the vanishing core removing rubber mold 40. That is, after the first disappearing material made of, for example, a water-soluble resin or wax is injected into the disappearing core removing rubber mold 40 and solidified, the formed disappearing core 44 is taken out.

Then, as shown in FIG. 6, the vanishing core 44 is placed in the vanishing model rubber mold 42, and the cavity in the vanishing model rubber mold 42 is made of a material different from that of the vanishing core 44. A second disappearing material, in this embodiment, a water-insoluble resin or wax is injected and solidified. As a result, not only the cavity in the disappearing model rubber mold 42 but also the wing portion cavity 44 formed in the disappearing core 44.
Also, the second vanishing material flows into a and fills the cavity 44a.

Then, the rubber mold 42 for the disappearing model is opened,
The vanishing model 46 integrated with the vanishing core 42 as shown in FIG. 7 is taken out and immersed in water to elute only the water-soluble vanishing core 44. As a result, the missing core 44
As shown in FIG. 8, the space having the holes serves as a cavity, and a vanishing model 46 having a shape corresponding to a male mold having a main plate, side plates, and wings is obtained.

It is to be noted that the injection of the second disappearing material does not affect the first disappearing material, that is, at a temperature at which the disappearing core 44 made of a water-soluble resin or wax is not melted. Is preferred. Specifically, for example, a water-soluble wax is poured into the disappearing core removing rubber mold 40 at a casting temperature of 100 ° C. and solidified to form a core 44.
The core 44 is placed in the rubber model 42 for disappearing model, and a water-insoluble wax is poured at a casting temperature of 70 ° C. to be solidified.

A fluid refractory material is coated on the periphery of the vanishing model 46 thus produced and solidified to form a shell, and the shell is heated to elute the vanishing model 46.
A casting mold is made.

[0027]

As described above, according to the present invention,
An integrated vanishing model having cavities corresponding to the main plate, the side plates, and the wings can be manufactured easily and accurately while preventing generation of burrs. Therefore, by producing a mold using this, there is an effect that an impeller having a complicated shape can be cast with good reproducibility.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing respective master molds of a main plate, side plates, and a core according to an embodiment of the present invention.

FIG. 2 is a view for explaining a rapid model manufacturing method.

FIG. 3 is a cross-sectional view for explaining a method for producing a rubber mold for removing a core that has disappeared.

FIG. 4 is a cross-sectional view for explaining a method of manufacturing a rubber mold for a disappearing model.

FIG. 5 is a plan view showing a lost core according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a step of manufacturing a vanishing model according to the embodiment of the present invention.

FIG. 7 is a sectional view showing a vanishing model having a vanishing core.

FIG. 8 is a sectional view showing a vanishing model according to the embodiment of the present invention.

FIG. 9 is a perspective view showing an impeller of a turbomachine manufactured according to the embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a mold used in a conventional investment casting method.

FIG. 11 is a plan view showing a state in which a core is formed by combining divided cores.

FIG. 12 is a sectional view showing a mold used for manufacturing a split core.

FIG. 13 is a cross-sectional view showing an example of manufacturing a mold in the order of steps.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Core master mold 12 Main plate master mold 14 Side plate master mold 20 Selective laser sintering device 40 Rubber mold for vanishing core removal 42 Rubber mold for vanishing model 44 Core 46 Vanishing model 100 Main plate 102 Side plate 104 Wing 106 Blade car

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshiyuki Ogawa 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Works Co., Ltd. (72) Inventor Akira Sasaki 11-1 Haneda Asahimachi, Ota-ku, Tokyo Co., Ltd. EBARA F-term (reference) 4E093 GA01 GC20 GD02 GD10 JA10

Claims (5)

[Claims] 1. A method of manufacturing a vanishing model for manufacturing a mold for casting an impeller having wings disposed between a main plate and a side plate, comprising: a master die having an overall shape of the impeller. A step of preparing a die for a disappearing model; a step of preparing a die for removing a core based on a master mold of a core corresponding to a cavity between the main plate and the side plate; and Injecting a first vanishing material into a mold to produce a vanishing core; placing the vanishing core in the vanishing model mold and injecting a vanishing core, including the vanishing core A method for producing a disappearing model, comprising: a step of producing a disappearing model; and a step of removing the disappearing core by means for selectively removing only the first lost material. 2. The method for producing a lost model according to claim 1, wherein the lost core removing die and / or the lost model die is made of a rubber-like material. 3. The method according to claim 1, wherein the core master mold is manufactured by a rapid model manufacturing method. 4. The method according to claim 1, wherein each of the master molds of the main plate and the side plate is manufactured by machining.
The method for producing a disappearing model according to the above. 5. A method for producing a mold, comprising using the disappearance model produced by the method according to claim 1 to produce the mold.