JPH04178237A - Molding flask, production of casting mold by this molding flask, as well as production of casting by this casting mold - Google Patents

Abstract

PURPOSE:To obtain the casting mold in a short period of time and to improve production efficiency by providing a hermetic type housing having an inlet and outlet for gas via a gas passage on the outer side of an air permeable housing. CONSTITUTION:The air permeable housing 1 is provided via the gas passage 4 in the hermetic type housing 3 having the inlet and outlet 5 for the gas and a combustible expendable pattern 6 is housed in this air permeable housing. Air permeable refractories 10 in the form of a slurry are packed into the excess space thereof and are dried; thereafter, gaseous oxygen is force fed from the outer side of the air permeable housing on the inner side thereof from the inlet and outlet of the above-mentioned hermetic type housing through the gas passage therein into this housing to burn and expend the above-mentioned expendable pattern on the inner side thereof to form a cavity in the trace thereof. The inside surface layer of the above-mentioned air permeable refractories is simultaneously cured by this combustion to form a casting mold layer. A molten metal is poured into this cavity while a negative pressure is maintained in the above-mentioned gas passage. After this molten metal is cooled, the above-mentioned casting mold layer is broken. Even if the casting mold is formed to an intricate shape or a thin shape, the precise product having the same shape as the shape of this mold is easily cast in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a flask used for manufacturing relatively high-precision cast products such as those manufactured by machining, and a method for manufacturing a mold using the flask. The present invention also relates to a method for casting a casting using the mold.

[Prior Art] The lost wax method has been widely used as one of conventional precision casting methods.

This method creates a wax mold with the same shape as the cast product,
This wax mold is immersed in a liquid binder and taken out, a layer of binder is formed on the surface of the wax mold, fine sand or other refractory powder is applied onto the binder layer, and this is dried. After this drying, it is immersed in the binder again,
The refractory powder is applied onto the binder layer, adhered, and dried. Thereafter, this process is repeated several times to layer the refractory powder on the surface of the wax mold until a predetermined strength is obtained. Then, this wax mold and its outer layer of refractory powder are heated together to melt and flow out the wax mold, and the layer of refractory powder is used as a mold, and molten metal is poured into it. casting.

After cooling the molten metal, the mold is destroyed and the cast product is taken out.

[Problems to be Solved by the Invention] However, the conventional lost wax method described above has the following drawbacks. This is because it takes a long time to form a mold.6 For example, forming a layer of wax-shaped refractory powder granules requires a drying process that lasts for 5 to 6 hours, so the entire process takes at least 24 hours. It requires

This invention was made to solve these problems, and its purpose is to provide a casting flask and a mold manufacturing method using the flask, which can further reduce the time required for the mold manufacturing process compared to the conventional forward bending method. Another object of the present invention is to provide a method for casting a casting using the mold.

[Means and operations for solving the problems] Regarding this invention that achieves the above object, firstly, the casting flask is described.It is a hermetic casing having an inlet and an inlet for gas through a gas passage on the outside of the air permeable casing. It is a casting flask that is characterized by having a body.

Next, the method of manufacturing a mold using the flask described above will be described.
A ventilated casing is provided in a sealed casing equipped with an inlet/outlet for gas, with a gas passage separated from the casing, and a flammable and fugitive model is housed in the ventilated casing, leaving the remaining space. is filled with a slurry-like breathable refractory, and after drying it, oxygen gas is injected from the outside of the breathable case inside through the gas passage in the airtight case through the entrance and exit of the airtight case. , a method for manufacturing a mold, characterized in that the fugitive model inside the mold is burnt out, and the inner layer of the breathable refractory is hardened by the combustion to form a mold layer. Also, a casting method using a mold manufactured by the above method is described. In this method, a gas-permeable housing is provided in a sealed housing provided with an inlet/outlet for gas, and a gas passage is separated from the air-permeable housing. A combustible fugitive model is housed in the casing, the remaining space is filled with a slurry-like breathable refractory material, and after drying, the air is passed through the gas passage through the entrance and exit of the airtight casing, Oxygen gas is pressurized from the outside of the breathable casing on the inside to burn and burn out the fugitive model on the inside to form a cavity in its wake, and as a result of the combustion, the inner layer of the breathable refractory material The casting method is characterized in that a mold layer is formed by hardening the metal, a molten metal is injected into the cavity with negative pressure in the gas passage, and after cooling the mold layer, the mold layer is destroyed. .

[Embodiment] In FIG. 1, reference numeral 1 designates a breathable housing, which is formed in what is called a two-part design by way of example, and is formed from two similar breathable housing members 2.2.

The air-permeable casing 1 is formed of an air-permeable porous body, and is formed so as not to pass through the air-permeable refractory slurry, which will be described later. This air permeable housing 1 is formed of a porous metal body, a porous body made of ceramic, porcelain, or the like.

It should be noted that there is no problem in using other porous materials such as concrete, or a so-called microporous sheet that is supported by a support and is liquid-tight and allows only gas to pass through, as shown in Figure 4. good.

In short, any material that is liquid-tight and allows only gas to pass through can be used without any problem. When metal is used, an open-cell porous body is formed from iron, copper, aluminum, brass alloy, so-called brass, or the like. Alternatively, it is formed in a porous body of earthenware or porcelain, and is formed in a so-called bisque shape. In such a case, a reinforcing material such as a punched metal plate or wire mesh may be provided inside.

3 is a sealed casing, allowing gas to pass through! It is provided on the outside of the air-permeable casing 1 with lIr4 in between.

The airtight housing 3 may be formed integrally with the air-permeable housing 1 as shown in FIG.
They may be formed separately as shown in FIG. 4, but in those shown in FIGS. 3 and 4, both L and 3 may be formed integrally, or In this case, glaze is applied to make it airtight. Alternatively, it may be simply formed to have poorer air permeability than the air permeable housing 1 without applying a glaze or the like.

This is almost the same when it is made of concrete.

Reference numeral 5 indicates a gas inlet/outlet, and a flammable and fugitive model 6 is housed in the breathable housing 1 . The fugitive model 6 is a model of a product to be cast, and is made of styrofoam and wax, for example. In addition to the above-mentioned foamed polystyrene made from pure styrene resin, various modified polystyrenes made from other synthetic resins were also used.

When the disappearing model 6 is housed in the air-permeable housing 1, it is housed in a suspended state by a hanging part 7 made of the same material or made separately, as shown in the figure. Note that the states shown in FIGS. 1 to 4 show the state where filling of the slurry of the breathable refractory material described later has been completed, and the state where the fugitive model 6 is pulled up. In the case of the above-mentioned filling, the model 6 is located further below the illustrated state, and a gap is formed between it and the injection port 8, and the slurry of the breathable refractory material, which will be described later, is injected from this gap. . Note that instead of using the hanging part 7, a stand made of a non-metallic fireproof material (not shown) may be used, and it is more preferable if the stand is breathable.

Furthermore, if the air permeable housing 1 is made of non-metallic material, it may integrally protrude into the interior to form a base.

Note that 9 is a runner, and the runner 9 is provided with an integral or separate hanging portion 7 as shown in the above □.

Next, reference numeral 10 is an air-permeable refractory, and refractory 0 is first injected as a slurry through the injection port 8 and dried and solidified. The slurry of the air-permeable refractory 10 includes, for example, water, clay, a dispersant, a binder, a thickener, etc., the fractional agent is, for example, gelatin, casein, etc., and the binder is, for example, $1 honey. was used, and methylcellulose was used as an example of the thickener.

Note that there are many possible formulations for the slurry in addition to those listed above. This is essentially a slurry at first, suitable for injection, and then
Any type may be used as long as it becomes a breathable refractory upon drying.

In FIG. 1, the housing member 2 and the hermetic housing 3 are integrally formed as shown, forming a flask member 11. A fixing member for fixing the two flask members 11 and 11 facing each other as shown in FIG. 1 is omitted from illustration. Reference numeral 12 indicates the flask formed in this manner. In addition, in FIG. ．．
FIG. 4 shows a case where a lid body 13 is provided across a cylinder body 14, and a hole 15 is formed in a cylinder body 14 as an air permeable housing 1.
5 is covered with a known microporous sheet 16 that is liquid-tight and allows only gas to pass through.

The self-microporous sheet 16 is a plastic sheet that does not allow liquid to pass through, but allows only gas to pass therethrough, and is known in the art.

In addition, in FIG. 4, the sheet 16 may be provided on the outside of the cylinder 14, or instead of the sheet 16, ceramic,
A porcelain, unglazed plate, etc. may also be provided.

Next, the method for manufacturing this mold will be described. First, the fugitive model 6 is suspended and housed in the air-permeable casing 1 inside the airtight casing 3, and then from the injection port 8, The slurry of the air-permeable refractory 10 is filled.

Then, this slurry is filled between the flammable and fugitive model 6 and the breathable housing 1. At this time, the slurry is dried by sucking the air in the gas passage 4 using a suction pump from the zero-order pre-inlet/outlet 5 which is vibrated by a vibration device (not shown). In this case, the slurry is dried and solidified by suction of air through the breathable housing 1.

Once the slurry has dried and solidified in this way, the fugitive model 6 is then ignited through the injection port 8 and burned. In that case, oxygen gas is pressurized through the inlet/outlet 5. As a result, the fugitive model 6 burns and burns out to form a cavity. Further, in that case, the inner layer of the breathable refractory 10 is hardened by this combustion, and a mold layer is formed. In the case of this combustion, if the fugitive model 6 is foamed polystyrene, it will burn very easily when ignited, but if the fugitive model 6 is made of wax, it will be burned by the combustion device 17 as shown in FIG. Burn it.

This combustion device 17 combusts combustible gas supplied through a pipe 18 at the tip of the pipe 18, for example.

Once the mold is formed in this way, from the injection port 8,
Inject molten metal.

In this case, air is sucked through the inlet/outlet 5 by a suction pump to create a negative pressure in the mold layer.

Once the molten metal has cooled and solidified, the mold layer is removed from the air-permeable housing 1, which is broken, and the cast product is taken out.

[Effects of the Invention] Because the present invention is configured as described above, the drying process, which takes a long time, is required only once in the process of manufacturing a mold, and it is not necessary to perform the drying process multiple times as in the conventional mold manufacturing method. Compared to methods that require a drying process, a mold can be obtained in an extremely short time, and the manufacturing efficiency can be significantly improved.

Furthermore, since the mold layer is injected in the form of a slurry, it is possible to accurately form the evanescent model even when the evanescent model has a complicated shape or a thin wall.

After the breathable refractories are dried, oxygen gas is injected from the outside of the airtight casing through the gas passage inside the airtight casing from the inlet/outlet of the airtight casing. Since the fugitive model is burned and destroyed, the inner layer of the dry air-permeable refractory can be hardened by the heat of the combustion gas generated at that time, and the strength of the mold layer can be increased.

Furthermore, since the strength of the mold layer can be increased in this way, there is no risk of destruction of the mold layer even if negative pressure is applied to the mold when pouring molten metal, resulting in the shape of the evanescent model. Even if it is complexly formed or thin-walled, it is possible to create a precision product with the same shape by casting, and it is possible to create shapes and wall thicknesses that are difficult to obtain without conventional machining. Even objects can be easily cast.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a mold manufactured by the mold manufacturing method using the flask of the present invention, FIG. 2 is a plan view of the mold shown in FIG. 1,
3 is a diagram corresponding to FIG. 1 showing another embodiment of the invention, FIG. 4 is a diagram corresponding to FIG. 1 showing still another embodiment of the invention, and FIG. 5 is a diagram corresponding to FIG. 1 showing another embodiment of the invention. It is a figure showing one process of a casting method. 1... Breathable casing 2... Casing member 3... Airtight casing 4... Gas passage 5... Gas inlet/outlet 6... Flammable dissipative model 8... Inlet 10... Breathable refractory

Claims (1)

[Scope of Claims] 1. A casting flask, characterized in that an airtight casing is provided with an airtight casing having an inlet and an inlet for gas through a gas passage on the outside of the air permeable casing. 2. A flammable and dissipative model is housed in a breathable housing,
The remaining space is filled with a slurry of breathable refractories, and after drying, oxygen is injected from the outside of the breathable casing through the breathable refractories, and the fugitive model inside is burned. A method for manufacturing a mold, characterized in that the inner layer of the breathable refractory is hardened by the combustion to form a mold layer. 3. A ventilated casing is provided in the airtight casing equipped with a gas inlet/outlet, with a gas passage separated, and a flammable and fugitive model is housed in the ventilated casing. After filling the space with a slurry-like breathable refractory and drying it, oxygen gas is injected from the outside of the breathable case inside through the gas passage in the airtight case through the entrance and exit of the airtight case. A method for manufacturing a mold, characterized in that the fugitive model inside the fugitive model is burnt out, and the inner layer of the breathable refractory is hardened by the combustion to form a mold layer. 4. A ventilated casing is provided in the airtight casing equipped with a gas inlet/outlet, with a gas passage separated, and a flammable and fugitive model is housed in the ventilated casing. After filling the space with a slurry-like breathable refractory and drying it, oxygen gas is injected from the outside of the breathable case inside through the gas passage in the airtight case through the entrance and exit of the airtight case. Then, the fugitive model inside is burnt and destroyed to form a cavity in its wake, and the inner layer of the breathable refractory is hardened by the combustion to form a mold layer, and the inside of the gas passage is A casting method characterized by injecting molten metal into the cavity under negative pressure, cooling the molten metal, and then destroying the mold layer.