JPH08155587A - Special core for molding - Google Patents

Abstract

PURPOSE: To provide a special core for molding capable of efficiently producing a molding of casting, plastic molding, ceramic molding, etc., without any constraint of shape and having excellent quality and wide range of shape. CONSTITUTION: A resin core 1 is made of synthetic resin and is formed to hollow shape having a hollow part S. Part of thickness in the resin core 1 is formed to non-uniform thickness, the non-uniform part is formed to a local thin thickness part N, which has a prescribed length L and approximately uniform thickness. When a thickness T of non-thin thickness part N is, for instance, 5mm, a thickness of thin thickness N is made 2mm. The thin thickness parts N are formed at two places at a prescribed distance on the same periphery of the resin core 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a special molding core, and particularly to a hollow shape or an undercut shape capable of preventing deformation or damage of a molded product due to the influence of a molding material such as molten metal. The present invention relates to a molding special core that can be used to obtain a cast product such as a die-cast cast product in which the above are formed, or a molded product such as a plastic molded product or a ceramic molded product.

[0002]

2. Description of the Related Art In casting adopted as a part of machining, a hollow shape and an undercut shape are formed.
Non-disintegrating cores or disintegrating cores are used.

By the way, there is a metal core as the former (non-collapsible core), but it cannot be used except for those that can be directly punched or deformed, and the range of use is limited to that of a specific shape.

As the latter (disintegrating core), there is a sand core in which a binder and a curing agent are mixed and fired, but it is difficult to mold and handle, and it easily collapses, and the pressure resistance during casting and the collapse after casting. Since it is difficult to combine with the property, it becomes glassy after casting and it is difficult to completely remove it.

Therefore, it has been proposed to apply a mold coating agent to the surface of the sand core, but there is a problem that defective products are generated due to the adverse effects such as the formation of porosity and shrinkage due to the permeation of the components, and the problem cannot be solved.

Further, in the die casting, the sand core cannot be used due to a defect such as insufficient strength. For example, it is impossible to form the hollow shape or the undercut shape of the intake manifold or the exhaust manifold of the engine by the die casting. There was a problem.

The sand core is difficult to mold and easily collapses.
It has many drawbacks such as difficulty in handling, and it is difficult to meet the contradictory conditions of pressure resistance during casting and disintegration after casting.Therefore, multiple steps are required from the factor of increasing the number of steps due to sand core characteristics, It had the drawback of being time consuming and expensive.

On the other hand, plastic molding and ceramic molding have various problems similar to the above casting.

For example, the molding core needs to be formed from a specific material having pressure resistance and heat resistance during molding, which causes problems such as difficulty in molding the core and high cost.

Therefore, in order to solve these problems, the present inventor first forms a hollow shape or an undercut shape into a cast product such as die casting, a molded product such as a plastic molded product or a ceramic molded product. In a molding core used for, a molding special core characterized by forming the molding core from a non-sand core, and a molding method using the molding special core, and A molded product molded using the special core has been proposed (Japanese Patent Application Nos. 4-339733 and 4-33).
9734, Japanese Patent Application No. 4-339735, etc.).

By the way, when the molding core is formed of a non-sand core to form a molding special core, and when a molding method using the molding core is used, the size and shape of the molded product are obtained. Depending on the type, there is a problem that deformation or damage may occur during molding.

[0012] After that, the present inventor continued further research,
As a molding special core that can solve the problems such as relatively large things such as engine intake manifold and exhaust manifold, hollow shape and undercut shape of complicated shape can be formed by die casting,
The more suitable one was investigated.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by adopting the following constitution.

That is, by using a specific molding special core, when the molten metal is pressurized and poured into the mold and then the molten metal is cooled, the die cast casting product is deformed or damaged due to the influence of the molten metal or the like. By preventing this, it is possible to obtain a cast product such as a die cast product having a target shape in which a hollow shape or an undercut shape is formed.

On the other hand, also in the case of plastic molding or ceramic molding, by using a specific molding special core as in the case of casting such as die casting, molding is performed in the same manner as in the case of the casting method such as die casting. After the molding material is injected into the mold, when the molding material is cooled, deformation or damage of the molded product due to the influence of the molding material or the like is prevented to form a hollow shape or an undercut shape. It is possible to obtain a molded product having a desired shape.

[0016]

According to the present invention, such an object is used for forming a hollow shape, an undercut shape or the like into a molded product such as a cast product, a plastic molded product or a ceramic molded product. In the molding core according to the present invention, the molding core is formed of a non-sand core, and a space is formed inside the molding core, and the meat of the molding core is formed. This is achieved by providing a special molding core, characterized in that part or all of the thickness is formed to have a non-uniform thickness.

[0017]

According to the present invention as described above, there are the following actions.

That is, according to the present invention, when the molding material is cooled, a part of the molding special core having the non-uniform thickness is deformed, so that the molding product is influenced by the molding material or the like. It is possible to prevent the deformation and damage of the above, and to mold it into a target shape having a hollow shape or an undercut shape.

That is, according to the present invention, by using a specific molding special core, not only the hollow portion and the undercut portion, which cannot be formed by the conventional die casting, can be easily formed. Regardless of shape or size, all shapes and sizes can be cast, and after the molten metal is poured under pressure into the mold, when the molten metal is cooled, the thin-walled forming part deforms and the die cast product By creating a gap between the die and the die, the die cast casting is prevented from being deformed or damaged due to the influence of molten metal, etc., and the die cast casting of the target shape with a hollow shape or undercut shape is formed. And the like can be obtained.

On the other hand, also in the case of plastic molding or ceramic molding, by using a specific molding special core, as in the case of casting such as die casting, as in the case of the casting method such as die casting, Not only is it easy to form hollow shapes and undercut shapes, but it is also possible to mold all shapes and sizes regardless of shape and size, and after injecting the molding material into the mold, The purpose of forming a hollow shape or an undercut shape by preventing deformation or damage of the molded product due to the influence of the molding material or the like due to deformation of the thin-walled forming portion when the molding material is cooled A shaped molded article can be obtained.

Further, by doing so, it is possible to improve the productivity and expand the range of application, and it is possible to efficiently obtain a molded product of a desired shape with excellent quality.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

1 to 3 show a first embodiment of a special molding core according to the present invention.

That is, the present invention relates to a molding core used for forming a hollow shape, an undercut shape or the like into a molded product such as a cast product, a plastic molded product or a ceramic molded product. The core is formed from a non-sand core, and a space is formed inside the molding core,
Moreover, the molding core is characterized in that part or all of the wall thickness of the molding core is formed to have a non-uniform thickness.

Therefore, the non-sand core used in the present invention is
Both conditions of non-disintegration during molding (heat resistance and pressure resistance) and disintegration after molding (heat disintegration, solvent disintegration, etc.) are required. Further, the non-sand core is required to have a condition that does not exert a bad influence on the molded product such as generation of a large amount of gas during the molding.

The present invention will now be described in detail with respect to specific embodiments with reference to the accompanying drawings.

4 and 5 show a first embodiment of the special molding core of the present invention.

Here, the case where a core made of synthetic resin (plastic) is used as the non-sand core which is the molding special core will be described.

A core (synthetic resin core or plastic core) made of synthetic resin (plastic) as the non-sand core (hereinafter referred to as "resin core") 1 is made of synthetic resin (plastic). .

The resin core 1 is formed of a synthetic resin into a hollow shape having a hollow portion S by a synthetic resin molding method (plastic molding method) such as injection molding.

As the synthetic resin (plastic), there is, for example, a polycarbonate synthetic resin (polycarbonate plastic) which is excellent in heat resistance and moldability, and as shown in FIGS. The hollow resin core 1 formed inside is molded.

As shown in FIGS. 4 and 5, the resin core 1 is formed so that a part of its wall thickness is nonuniform.

The resin core 1 has a non-uniform thickness portion,
It is formed in the locally formed thin portion N. Further, the resin core 1 is formed by forming the local thin-wall forming portion N to have a predetermined length L and a substantially uniform thickness.

For example, in the hollow resin core 1 having the hollow portion S formed therein, the thickness T of the non-thin portion is 5 mm.
When, the wall thickness t of the thin wall forming portion N is 2 mm.

Further, the local thin-walled forming portions N are formed at two locations on the same peripheral surface of the resin core 1 so as to be adjacent to each other with a predetermined distance.

As described above, the resin core 1 is formed in a hollow shape having the hollow portion S therein, and the wall thickness of two adjacent portions on the same peripheral surface is a predetermined length over a predetermined width. Thus, the thin portion N is locally formed.

Then, using the molding special core 1,
It is possible to form a cast product such as die-cast casting or a molded product such as a plastic molded product or a ceramic molded product.

For example, when a molded product such as a cast product, a plastic molded product or a ceramic molded product is molded using the resin core 1, as shown in FIG. It is possible to form the molding die 4 which is disposed between the mold 2 and the lower mold 3 and has the cavity 5 having a shape corresponding to the shape of the molded product 6 to be molded.

The special molding core used in the method of the present invention is not limited to the above-mentioned embodiment, but many modifications are conceivable and can have different structures, shapes and sizes. Of course.

For example, FIG. 7 is a cross-sectional view showing a second embodiment of the molding special core used in the method of the present invention. Since the hollow resin core 1 has a small size, it is substantially uniform. Only one local thin thickness forming portion N is formed on the same circumferential surface of the resin core 1.

FIG. 8 is a cross-sectional view showing a third embodiment of the molding special core used in the method of the present invention. Since the hollow resin core 1 has a large size, The local thin-walled portions N having a substantially uniform thickness are formed at four locations on the same circumferential surface of the resin core 1.

Further, FIG. 9 is a cross-sectional view showing a fourth embodiment of a special molding core used in the method of the present invention. The hollow resin core 1 is formed so that the entire thickness is non-uniform. As described above, the thin-wall forming portion N is formed by gradually forming the entire wall thickness to be non-uniform.

According to the present embodiment, as well shown in FIG. 10, when the molten metal is cooled, the thin wall forming portion N is deformed into a substantially M shape (a substantially mountain shape or a substantially wave shape), and a molded product is obtained. A gap is created between the cast product 6 and the cast product 6, which can prevent the cast product 6 from being deformed or damaged, and can cast a die cast cast product 6 having a desired shape in which a hollow shape or an undercut shape is formed. .

FIG. 11 is a cross-sectional view showing a fifth embodiment of the molding special core used in the method of the present invention, in which the hollow thin resin core 1 has a local thin-walled portion having a substantially uniform thickness. Two Ns are formed on the same peripheral surface of the resin core 1 so as to face each other.

As described above, since the resin core 1 is formed in a hollow shape having the hollow portion S inside, and is formed in the thin-walled forming portion N over a predetermined width and with a predetermined length, the molten metal is formed. During cooling, as shown in FIG. 6, the thin-walled forming portion N is deformed and a gap is formed between the thin-walled forming portion N and the die-casting product 6, thereby deforming the die-casting product 6 due to the influence of the molten metal. It is possible to cast a casting 6 excellent in quality of a target shape in which a hollow shape or an undercut shape is formed by preventing defects such as damage and breakage.

At this time, the molding special core used in the present invention is not limited to the above-mentioned embodiment, but various shapes, sizes and forming positions of the thin wall forming portion N, and the core itself. It can be applied to various shapes using various molding special cores, such as having various shapes and sizes, can improve the quality of molded products, and is not limited to the above-mentioned examples.
Many variations are possible.

For example, the number of the thin-walled forming portions N is not limited to one, two or four in the above-mentioned embodiment, but it is needless to say that the number may be three, five or more, which is the other number. Is. The shape of the thin-walled forming portion N is not limited to the shape having the uniform thickness in the above-described embodiment, and it is needless to say that the thin-wall forming portion N can be formed in the shape having other nonuniform thickness. further,
The shape of the thin-wall forming portion N is not limited to the shape in which a part of the wall thickness of the above-described embodiment is formed to be substantially uniform, and it goes without saying that a part of the wall thickness can be formed to have a non-uniform thickness.

Next, a method for molding a molded product using the resin core 1 will be described in detail.

In the present embodiment, by using the above-mentioned non-sand core, casting products such as die casting products having a desired shape in which a hollow shape or an undercut shape is formed, plastic molding products, ceramic molding products, etc. Among the molding methods using a special core, which is characterized by molding a molded product, a casting method using a special core for molding a cast product will be described.

Here, in the case of performing die casting which is excellent in productivity as one of the casting methods, a non-sand core is used.
The case of using the resin core 1 will be described.

That is, in this embodiment, casting is performed in the following steps.

First Step Although not shown in the drawings, a polycarbonate synthetic resin (polycarbonate plastic) having excellent heat resistance and moldability is used among the synthetic resins (plastics) in the same manner as described above. And as best shown in FIG.
The hollow resin core 1 having the hollow portion S formed therein is molded.

The resin core 1 has the hollow portion S as described above.
It is formed in a hollow shape having an inside, and is formed in a local thin-walled forming portion N with a predetermined thickness over a predetermined width and at two locations on the same peripheral surface.

Second Step Subsequently, as shown well in FIG. 1, the resin core 1 is disposed between the upper mold 2 and the lower mold 3 so that a hollow shape or an undercut shape is formed. A mold 4 having a cavity 5 corresponding to the shape of the formed die-cast product is formed.

Third Step Next, as best shown in FIGS. 1 and 2, a pressure is applied to a molten metal such as an aluminum molten metal in the cavity 5 formed in the mold 4 depending on the material of the cast product. Pouring while adding.

At this time, since the resin core 1 has a large heat capacity, it has a high heat resistance against the molten metal and a high pressure resistance. The initial shape can be retained without deformation. Further, the temperature of the molten metal is about the initial temperature (for example, about 6% for aluminum molten metal) before reaching the cavity 5 of the mold 4.
Since the temperature decreases compared to 60 degrees C), the resin core 1
Due to its own temperature and heat capacity, the initial shape can be maintained without immediate melting even when the molten metal acts.

Therefore, the casting 6 having a shape corresponding to the shape of the cavity 5 is cast in a state where the original shape is maintained without deforming the resin core 1.

Fourth Step Subsequently, as shown in FIGS. 2 and 3, the high-pressure molten metal poured as described above is cooled to form a hollow shape or an undercut shape. A die cast product 6 having a shape is formed. The cooling includes natural cooling and forced cooling, but in the present embodiment, natural cooling is performed.

At this time, as shown in FIGS. 4 and 5, the resin core 1 is formed such that a part of its hollow wall thickness is nonuniform. Further, the resin core 1 has a non-uniform thickness portion formed in a local thin-wall forming portion N, and the thin-wall forming portion N is formed by thinning a predetermined length L into a substantially uniform thickness. Has been done. For example, when the thickness T of the non-thin portion of the resin core 1 is 5 mm, the thickness t of the thin portion N is 2 mm.

The thin-wall forming portion N is formed at two locations on the same peripheral surface of the main body G.

In this way, the resin core 1 is formed in the local thin-walled forming portion N having a predetermined thickness over a predetermined width such that the thicknesses of the two locations on the same peripheral surface are predetermined.

Furthermore, after the molten metal is poured under pressure into the casting mold 4, when the molten metal is cooled, the thin-walled forming portion N having a substantially uniform thickness is deformed. That is, as well shown in FIG. 6, the arcuate thin-walled forming portion N forming a part of the cylindrical shape is deformed into a substantially M shape (a substantially mountain shape or a substantially wave shape), and is a molded product. A gap is created between the cast product 6 and the cast product 6.

As described above, the arc-shaped thin-walled forming portion N, which is a part of the resin core 1, is deformed into a substantially M-shape, so that the cast product 6 due to the influence of the molten aluminum, which is a casting material, or the like.
Since it is possible to prevent defects such as deformation and damage of the
As well shown in FIG. 3, a cast product 6 having a desired shape in which a hollow shape C, an undercut shape U and the like are formed can be cast.

Fifth Step Subsequently, as shown well in FIGS. 2 and 3, a die-cast casting 6 having a target shape in which the hollow shape C and the undercut shape U formed as described above are formed is cast. Take out from 4.

Sixth Step Next, although illustration is omitted, the resin core 1 remaining inside the cast product 6 is removed to complete the casting.

At this time, the resin core 1 contributes to the formation of the desired casting 6 by maintaining its shape at the time of casting, and after casting, by the residual heat or heating of the casting 6. Melt and cast alone or in combination with drawing 6
It is removed from and eliminated so that no residue remains.

In this case, in this embodiment, the resin core 1 is removed by removing the residual heat alone or by combining the residual heat and the extraction, or by combining the residual heat and the heating, or the residual heat and the heating and extraction. Are used together, or both heating and drawing are performed together, or only heating is performed.

Further, the resin core 1 can be removed by using a solvent, particularly an organic solvent, without being limited to these, and the solvent removal can be carried out in combination with residual heat or withdrawal as in the above. And heating, or residual heat, heating and drawing, or heating and drawing, or the solvent alone.

As described above, in the case of die casting, which is the first embodiment of the molding method using the special molding core of the present invention, the resin core 1 retains its shape during casting. In addition to contributing to the formation of the intended cast product 6, after casting, the cast product 6 is melted and removed by residual heat or heating of the cast product 6 and can be removed without leaving a residue.

Seventh Step Further, although not shown in the drawing, unnecessary parts such as burrs of the cast product 6 are removed, and a die cast cast product having a desired shape in which a hollow shape C, an undercut shape U and the like are formed as a finished product. You can get a product that is

At this time, the resin core 1 is removed and disappears from the molded product, but depending on the shape and size, the whole or a part can be extracted and reused as the material of the resin core 1, thus reducing the material cost. Can be planned.

As described above, according to the first embodiment, by molding with a specific molding method using a specific molding special core, it is possible to obtain a hollow shape or an undercut which cannot be achieved by conventional die casting. Not only is it easy to form shapes, but it is also possible to form relatively large parts such as engine intake manifolds and exhaust manifolds, hollow shapes with complicated shapes, and undercut shapes by die casting. Regardless of the shape or size of the die, it is possible to cast the molten metal into the mold and then cool the molten metal. By preventing the generation, it is possible to obtain a cast product such as a die-cast cast product having a target shape in which a hollow shape or an undercut shape is formed. Therefore, as compared with the conventional sand core casting method, (1) core coating mold, (2) core drying, (3)
Sand removal of castings, (4) sand heat treatment (sand baking) of castings,
(5) The number of man-hours can be reduced by eliminating the need for the five steps of sand drop inspection of cast products.

Next, the operation of this embodiment will be described.

As described above, the molding method using the special molding core of this embodiment has the following effects.

That is, according to the present embodiment, the molten metal such as aluminum molten metal is poured into the hollow portion 5 formed in the mold 4 while applying pressure to the molten metal, and then the high pressure is poured. When the molten metal is cooled, the die-cast casting 6 having a desired shape is formed. When the molding material is cooled, a part of the special molding core having a nonuniform thickness is deformed. Then, the deformation or damage of the molded product due to the influence of the molding material or the like is prevented, and the product is molded into a target shape having a hollow shape or an undercut shape.

In this case, when the molten metal poured under pressure is cooled, the thin-wall forming portion N formed to have a substantially uniform thickness is deformed into a substantially M-shape, and a gap is formed between the thin-wall forming portion 6 and the cast product 6 which is a molded product. In this state, the cast product 6 is prevented from being deformed or damaged due to the influence of the molten aluminum, which is the casting material, and the die-cast cast product 6 of the desired shape in which the hollow shape C, the undercut shape U, etc. are formed. Can contribute to the casting of.

As described above, according to this embodiment, by molding with a specific molding method using a specific molding special core, it is possible to obtain a hollow shape or an undercut shape which is impossible by conventional die casting. Not only is it easy to form, but it is possible to form relatively large objects such as engine intake manifolds and exhaust manifolds, hollow shapes with complex shapes, and undercut shapes by die casting, regardless of shape or size. , Which enables casting of all shapes and sizes, and when the molten metal is cooled after being pressurized and poured into the mold, defects such as deformation and damage of the die cast product due to the influence of the molten metal may occur. It is possible to obtain a cast product such as a die cast cast product having a target shape in which a hollow shape or an undercut shape is formed.

Furthermore, by doing so, it is possible to improve the productivity and expand the range of application, and it is possible to efficiently obtain a molded product of the desired shape with excellent quality.

Next, a sixth embodiment of the present invention will be described with reference to the drawings.

That is, FIGS. 3 and 12 to 14 show a sixth embodiment of the present invention, in which a hollow shape, an undercut shape or the like is formed by using the molding special core of the embodiment. Of the molding methods for molding a molded product such as a cast product having a desired shape, a plastic molded product, and a ceramic molded product, the case of performing die casting will be described.

At this time, the first embodiment uses the resin core 1 having the hollow portion S, but in the sixth embodiment, the following non-sand core is used. Cast.

As shown in FIG. 12 and FIG. 13, the casting special core 1 which is a non-sand core has a hollow main body G in which a filling space S which is a hollow portion is formed, The filling body H is filled in the filling space S. The hollow main body G having the filling space S is formed of a polycarbonate synthetic resin which is a thermoplastic synthetic resin. In addition, the filling body H is formed of shirasu, which is a gravel of a mountain, which is a collapsible material, and is filled in the filling space S of the main body G.

Then, in the same manner as the casting method such as the die casting method of the first embodiment, the casting method such as the die casting method can be carried out by using the casting special core 1. The same effect as that of the embodiment can be obtained.

In this case, as well shown in FIG. 12, by cooling the poured high-pressure molten metal, the cast product 6 having the target shape shown in FIG. 3 is formed.

The cooling includes natural cooling and forced cooling. In this embodiment, natural cooling is used.

At this time, as shown in FIGS. 12 and 13, the casting special core 1 as the molding special core has a hollow shape in which the filling space S is filled with the filling body H. Two wall thicknesses on the same peripheral surface of the main body G are formed in a local thin-wall forming portion N over a predetermined width.
Is formed by forming a thin wall having a predetermined length L substantially uniformly (for example, when the wall thickness T of the non-thin wall forming portion of the hollow main body G is 5 mm, the wall thickness t of the thin wall forming portion N). Is 2 mm
Like).

Then, when the molten metal is pressurized and poured into the mold 4 and then the molten metal is cooled, the thin-walled forming portion N formed to have the substantially uniform thickness is deformed. That is, as well shown in FIG. 6, the arcuate thin-walled forming portion N forming a part of the cylindrical shape is deformed into a substantially M shape (a substantially mountain shape or a substantially wave shape), and is a molded product. A gap is created between the cast product 6 and the cast product 6.

In this way, the arc-shaped thin-walled forming portion N, which is a part of the casting special core 1, is deformed into a substantially M-shape,
As shown in FIG. 3, the hollow shape C and the undercut shape U are prevented by preventing defects such as deformation and damage of the cast product 6 due to the influence of the aluminum melt, which is the casting material.
It is possible to contribute to the casting of the die-cast casting 6 which is excellent in the quality of the target shape in which the above are formed.

The method of the present invention as described above is not limited to the die casting in each of the above-mentioned embodiments, but is applied to the sand type gravity casting method, the die gravity casting method, the low pressure casting method and the precision casting method, and other casting methods. Yes, in addition to obtaining the same excellent effects as each of the above examples, it can also be applied to other molding methods such as plastic molding and ceramic molding, the same excellent effects as each of the above examples can be obtained, and an object of excellent quality and It is possible to efficiently obtain a molded product such as a cast product having a desired shape.

The molding method using the special molding core of the present invention is not limited to the above-mentioned embodiments, and many modifications can be considered, and the same effects as those of the above-mentioned embodiments can be obtained.

Next, the operation of the sixth embodiment will be described.

Also in the case of the present embodiment, as in the first embodiment, after the molten aluminum or the like is pressurized and poured into the cavity 5 formed in the mold 4 according to the material of the cast product, the molten metal is cooled. As a result, the casting 6 having the desired shape is formed, but when the molten metal is cooled, the thin-walled forming portion N is deformed into a substantially M shape, and a gap is created between the casting 6 and the casting 6. It is possible to prevent defects such as deformation and damage of the cast product 6 due to the influence of molten metal and the like, and contribute to casting of the cast product 6 having the target shape in which the hollow shape C, the undercut shape U, and the like are formed.

In addition to the above, according to the above-described embodiment, the following remarkable effects are further obtained.

That is, according to the sixth embodiment, since the casting special core 1 uses the core filled with the filling material, the core has pressure resistance and heat resistance with the filling material filled. Since it is sufficient to satisfy the conditions such as the heat resistance and the like, the conditions such as pressure resistance and heat resistance required for the core can be relaxed, the selection range of the core material can be expanded, and the filler and the amount can be selected. By doing so, the pressure resistance and heat resistance of the core can be adjusted.
Further, since the heat-resistant main body G is integrally formed on the surface of the filling body H, the heat capacity is large, and the heat resistance and pressure resistance are high,
The initial shape can be maintained without thermal deformation or pressure deformation. Further, since the main body G is completely removed and disappeared due to residual heat of the cast product 6 and only the filling body H remains, it is easy to discharge the filling body H from the casting product 6 and the special core 1 for casting from the casting product 6 is obtained.
Can be completely removed, defects such as wear and damage of products can be prevented, the quality and yield of cast products can be improved, time and cost can be saved, and productivity can be improved.

Therefore, the cast product 6 having a shape corresponding to the shape of the hollow portion 5 is efficiently cast.

As described above, according to the present embodiment, by molding with a specific molding method using a specific molding special core, it is possible to obtain a hollow shape or an undercut shape which is impossible by conventional die casting. Not only is it easy to form, but it is possible to form relatively large objects such as engine intake manifolds and exhaust manifolds, hollow shapes with complex shapes, and undercut shapes by die casting, regardless of shape or size. It is possible to perform casting such as die casting of all shapes and sizes.

Therefore, since the surface of the special molding core used is smoother than the rough surface of the conventional sand core, the molded products molded according to the above-mentioned examples have a hollow shape or an undercut shape. The inner surface is formed as a smooth surface without a rough surface, eliminating the need for secondary processing such as machining for inner surface smoothing, and preventing defects in the molded product such as wear and damage to the molded product. It is possible to improve the performance of the product using the product.

Although the above-mentioned embodiments have all been described with respect to die casting, the molding method using the special molding core of the present invention is not limited to die casting, but sand sand gravity casting, die gravity casting, Of course, it can be applied to a pressure casting method, a precision casting method, and other casting methods. Further, the molding method using the molding special core of the present invention is not limited to the above-mentioned casting method, but can be applied to other molding methods such as plastic molding and ceramic molding, and is as excellent as the above-mentioned die-cast casting and other casting methods. The effect can be obtained, and a molded product having a desired shape and excellent quality can be efficiently obtained.

As described above, according to the method of the present invention, it is possible to efficiently form a wide variety of molded articles without being subject to shape restrictions, and it is possible to form a hollow article or an undercut article, a cast article, a plastic article or a ceramic article. It is possible to obtain molded products such as molded products.

Moreover, it is possible to mold all shapes and sizes without being restricted by the shape and size, the range of application is greatly expanded, the degree of freedom in design is improved, and the product performance is improved.
Further, the productivity can be improved and the cost can be reduced by reducing the weight.

Next, with reference to the attached drawings, a method for forming the special molding core used in the sixth embodiment will be described.

13 and 14 show a method of forming a special molding core for use in the sixth embodiment of the present invention. The special molding core 1 can be formed by various methods.

That is, the first is a method of forming the filling body H first, and then forming the main body G on the surface (outer surface) of the filling body H, and the second is the method of forming the main body G first and then the main body G. It is a method of forming by filling a collapsible material such as gravel of river, sea, or mountain into the inside of.

First, a first embodiment of the method for forming the molding special core 1 used in the method of the present invention will be described with reference to the drawings. That is, FIG. 13 and FIG. 14 show a first embodiment of the method for forming the molding special core used in the sixth embodiment of the present invention.

First, shirasu, which is gravel of a mountain as an inorganic material, is hardened with glue to obtain a filling body H having a predetermined shape. Subsequently, a polycarbonate synthetic resin, which is a heat-resistant synthetic resin, is formed on the surface of the filling body H with a predetermined thickness to form a main body G made of a heat-resistant main body. In this way, the molding special core 1 having a predetermined shape in which the heat-resistant main body G is formed on the surface of the filling body H can be formed.

If the special molding core 1 is used for molding, the strength is improved, the breakage is less likely to occur, and the handling is easy. Therefore, molding is possible regardless of the shape or size, and the application range is expanded and the productivity is improved. Therefore, it is possible to efficiently obtain a molded product having excellent quality.

Next, a second embodiment of the method for forming the molding special core 1 used in the method of the present invention will be described with reference to the drawings. That is, FIG. 13 and FIG. 14 show a second embodiment of the method for forming the molding special core used in the sixth embodiment of the present invention.

First, a polycarbonate synthetic resin is formed into a predetermined shape with a predetermined thickness, so that the filling space S is filled inside.
The main body G is formed of a heat-resistant main body having a hollow shape. Next, the filling space S of the main body G is filled with shirasu, which is a mountain gravel, and hardened with glue to form a filling body H having a predetermined shape. In this way, it is possible to form the special molding core 1 having a predetermined shape in which the filling body H is filled and formed in the filling space S of the main body G.

Further, if the molding is performed using the molding core 1, the strength is improved, it is hard to break and it is easy to handle, so that molding is possible regardless of the shape and size, and the range of application and the productivity are improved. Therefore, it is possible to efficiently obtain a molded product having excellent quality.

FIG. 15 shows a special core for molding of the seventh embodiment according to the present invention and an intake manifold for an engine which is a molded product. The intake manifold I of the engine has a complicated hollow shape and an undercut shape and is relatively large in size. Therefore, there has been a problem that deformation or damage may occur during molding conventionally. According to the molding special core of the invention, these problems are solved, and it is possible to form an intake manifold of an engine, which is a die-cast casting product in which a relatively large or complicated hollow shape or undercut shape is formed. Problems such as possible can be solved.

FIG. 16 shows an engine exhaust manifold which is a special molding core and a molded product according to the eighth embodiment of the present invention. Similar to the above embodiment, the exhaust manifold E of the engine has a complicated hollow shape and an undercut shape, and is relatively large, which may cause deformation or damage during conventional molding. However, according to the molding special core of the present invention, these problems can be solved, and problems such as die casting become possible can be solved.

The molding core, the filling body, and the main body of the present invention are not limited to the above embodiments, but can be applied to various materials, shapes, and sizes, and many modifications are conceivable. Besides being able to obtain the same effects as those of the above-mentioned respective examples, by using the molding special core of the present invention, it is not limited to the die-casting of the above-mentioned examples, and can be applied to the gravity casting method and other casting methods. Of course, it can be applied to plastic molding, ceramic molding, and other molding methods, and the same excellent effects as those of the above die casting and other molding methods can be obtained, and molding of all shapes and sizes is possible without being restricted by shape. Become.

Further, the molding using the special core for molding of the present invention is not limited to the molding method of the embodiment, but can be applied to molded products of various materials, shapes and sizes. To improve the quality of molded products by adding specific processes, etc.
The present invention is not limited to the molding method of the embodiment, and many modifications can be considered.

Further, the filling body which constitutes the special molding core of the present invention is required to have non-disintegrating property while the surface is covered with the main body at the time of molding and disintegrating property after molding. is there.

Fillers satisfying the above conditions include, for example, fillers made of an inorganic material such as gravel in rivers, seas and mountains, and other collapsible materials. Among them, as the inorganic material, there are river gravel, sea gravel, and mountain gravel, as well as raw foundry sand itself that does not contain a binder, a hardening agent, etc., or a powdery, granular, or lumpy ceramic ( There are new ceramics and old ceramics). Further, the filling body may be made of gravel, foundry sand, ceramics or the like alone, or may be a mixture thereof with a powdery, granular or lumpy metal. Examples of the metal include iron such as iron oxide, aluminum such as aluminum oxide, and other metals.

The main body may be formed on the entire surface of the filling body as in the embodiment, or may be formed on most (or part) of the surface of the filling body depending on the shape of the molded product.

The main body has non-disintegration properties (heat resistance and pressure resistance) at the time of molding, and disintegration properties (heat disintegration property, solvent disintegration property, etc.) after molding, and the filler is enclosed inside. It is required to protect and further completely prevent gas generation from the molding special core even if gas is generated in the filling body, and not to adversely affect the molded product. A material similar to the resin core as the sand core is suitable.

The resin core as the non-sand core which is the special molding core used in the method of the present invention, and the material of the main body which constitutes the non-sand core are non-disintegrating (heat resistant) during molding. Properties and pressure resistance) and disintegration property after molding (heat disintegration property, solvent disintegration property, etc.) are required, and it is required not to give adverse effects to the molded product such as gas generation during molding. .

Materials satisfying the above conditions include synthetic resins (plastics) and other materials. Among them, the synthetic resins include the following.

That is, the synthetic resin includes, for example, a thermosetting synthetic resin (thermosetting plastic) and a thermoplastic synthetic resin (thermoplastic), which have both of the above-mentioned conditions. It is possible to obtain a molded product that sufficiently satisfies

Further, the most suitable one of the thermoplastic synthetic resins is the polycarbonate synthetic resin of the example, which satisfies the above conditions and sufficiently satisfies the intended purpose. Can be obtained. Next to this, there are fluororesins (polyfluorethylene resins) such as tetrafluoroethylene resin, polyimide resins, polyamideimide resins and polysulfone resins,
Since all of the above conditions are satisfied, it is possible to obtain a cast product or other molded product that satisfies the intended purpose.

Next to this, there are polyamide resin (nylon resin) and polypropylene resin,
Since all of the above conditions are fulfilled, a molded product satisfying the initial purpose can be obtained. Further, other examples include polyethylene resin and polyester resin (Tetron resin), which have both of the above conditions and can provide a molded product satisfying the initial purpose.

Further, it is a matter of course that, as the synthetic resin, thermoplastic synthetic resins, thermosetting synthetic resins and other synthetic resins other than those in the examples and the above list can be used as long as they satisfy the above conditions. The same effect as that of the embodiment can be obtained.

Further, it goes without saying that other materials can be used as well as the synthetic resin material as long as the above conditions are satisfied.

Other materials satisfying the above conditions include heat-resistant synthetic rubber, rubber such as silicon rubber and fluorine rubber. For example, heat-resistant rubber such as silicon rubber can be mentioned. Any of the above conditions can be satisfied. However, it is possible to obtain the same effect as that of the above embodiment.

Further, as the material, other than the above synthetic resins and rubbers, low-melting metals such as tin, lead and antimony and ceramics, as long as they satisfy the above conditions,
In addition to other single materials, FRR (fiber reinforced rubber), FRP (fiber reinforced plastic) and GFR
P (glass fiber reinforced plastic) and other composite materials can be used, various materials can be used, and the same effects as those in the above-described embodiment can be obtained.

The resin core as a non-sand core, which is a special molding core for satisfying the disintegration property (heat disintegration property, solvent disintegration property, etc.) after molding, and the main body constituting the non-sand core Basically, it is dissolved and removed by residual heat of the molded product, but depending on the size and shape of the core and the molded product, it is difficult to dissolve and remove with only the residual heat of the molded product. And can be removed from a molded product such as a cast product.

In this case, the removal of the resin core and the main body is not limited to the method of completely dissolving and removing the resin core inside the molded product, but if the resin core or the like can be removed from the molded product, the surface of the resin core or the like is dissolved. It is possible to take out from the molded product in the state of being melted, or in a state in which a part or most of the resin core or the like is melted or in a state of semi-molten.

At this time, the remaining portion of the extracted resin core or the like has a great advantage that it can be reused without discarding, the cost can be reduced, and the pollution problem can be solved.

When the special core for molding or the main body is insufficiently or difficultly or impossiblely removed by residual heat or extraction, heating alone or heating in combination with residual heat or extraction can be performed. At this time, as a heating removal method, heating by a burner,
Heating in a heating tank, heating with high-temperature and high-pressure steam, heating with shot blasting to blast (jet) other shots such as metal powder such as alumina powder, heating with microwaves or electromagnetic induction heating,
There are other heating methods, and in any case, the non-sand core after molding can be completely removed by heating.

Further, depending on the shape of the molding special core or the shape of the molded product, in addition to residual heat, heating or drawing, a solvent, particularly an organic solvent, may be used alone or in combination with residual heat, heating or drawing. The special core or body can be removed from the molded product. This solvent removal method, there is a solvent spray removal or removal by immersion in a solvent tank, or removal by using a microwave immersed in a solvent tank, other solvent removal methods, in any case after molding The non-sand core can be completely removed by the solvent. As the solvent, when the molding special core or the main body is a polycarbonate synthetic resin, normal alkylbenzene (trade name "Nonion" or the like) is sufficiently satisfactory in terms of function and cost, and there is no problem in actual use. In addition to these, as the solvent of the polycarbonate synthetic resin, there are the following. For example, tetrachloroethane, methylene chloride, chloroform, 1,1,2 trichloroethane, etc. were able to obtain the same effect.

The solvent of the present invention is not limited to the solvent of the examples as long as it can dissolve the molding special core and the main body, and it is needless to say that various solvents can be used. Alternatively, the same effect as that of the embodiment can be exhibited by performing it independently.

Further, the removal of the molding special core or the main body of the present invention is carried out by using the residual heat alone or the combination of the residual heat and the heating of the embodiment, or by the heating alone or by a solvent such as an organic solvent. Not limited to those, if it is possible to effectively remove the molding special core or the main body, it goes without saying that other removal methods can be used, and many modified examples are possible,
The same effect as that of each embodiment can be obtained.

The molding special core of the present invention is not limited to the die cast casting of the above-mentioned embodiment, but it is possible to add a specific step to the die casting casting to further improve the quality of the cast product, and is limited to the above embodiment. Instead, many modifications are possible.

Further, the present invention is not limited to the die casting of the above-mentioned embodiment, but can be applied to the sand type gravity casting method, the die gravity casting method, the low pressure casting method and the precision casting method, and other casting methods. Many modifications are conceivable, and the same effect as the above embodiment can be obtained.

In this case, the effect of the present invention is particularly great in the above gravity casting method.

That is, in the gravity casting method, since the molten metal residence time is long, the core-to-molten metal contact time is long, and the molten metal temperature is relatively high, the core must have both pressure resistance and heat resistance. However, by using the molding special core of the present invention, the heat capacity becomes large as compared with the conventional sand core and the synthetic resin core etc. of the present inventors' prior application. The core temperature rise is small, the heat resistance and pressure resistance are improved, the initial shape is retained without thermal deformation or pressure deformation, and it can contribute to the formation of desired molded products of a wide range of excellent quality.

That is, even when a cast product is obtained by the gravity casting method using the special molding core of the present invention, the intended cast product can be obtained in the same manner as in the above-mentioned embodiment.

In this case, the temperature of the molten metal depends on the cavity 5 of the mold 4.
Until the temperature reaches the initial temperature (for example, about 750 degrees C for molten aluminum), the core has a large heat capacity in combination with improved heat resistance and pressure resistance. The temperature rise of the core at the time is relatively small, the initial shape can be maintained without melting without thermal deformation or pressure deformation, and it can contribute to the formation of a wide variety of high-quality molded products, and casting products can be obtained efficiently. To be

[0140] The cast product prevents defects such as porosity and shrinkage from occurring, significantly reduces man-hours as compared with the conventional sand core, and is a cast product excellent in appearance quality and functional quality.

Further, the special molding core used in the method of the present invention is not limited to the special molding core of the embodiment, and many modifications are conceivable. Furthermore, a molding method other than casting is a plastic molding method. It can also be applied to a molding special core used in a ceramic molding method, can solve various problems as in casting, and can exhibit the same excellent effects as in the embodiment.

Further, the special molding core used in the present invention is not limited to the above-mentioned embodiment, and it can be applied to various shapes using various special molding cores to improve the quality of molded products. However, the present invention is not limited to the above-described embodiment, and many modifications can be considered.

[0143]

As described above, according to the present invention, by using a specific molding special core, not only the productivity is improved and the range of application is enhanced, but also a molded product having excellent quality is obtained. It has the following excellent effects.

That is, using a special molding core in which a part or the whole of the molding core has a non-uniform thickness, a thin wall of the molding core is used when the pressurizing material is cooled. By deforming the forming part, it is possible to prevent defects such as deformation and damage of the molded product due to the influence of the pressurizing material and to contribute to the molding of the molded product of the target shape with the hollow shape and the undercut shape. You can In the conventional molding method such as casting, there was a problem such as deformation and damage of the molded product due to the influence of the pressure material during molding, but according to the method of the present invention, the deformation and damage of the conventional molded product All shapes such as hollow shapes and undercuts that could not be molded by die casting etc., large shapes or complicated shapes can be easily molded. And full-size molding is possible, the range of application is greatly expanded, design flexibility is improved, product performance is improved, productivity can be dramatically improved, and weight reduction etc. can significantly reduce cost. And the quality of the molded product can be significantly improved.

In addition to this, the following effects can be obtained in a casting method such as die casting. (1) The high-pressure molten metal poured into the cavity in the mold is cooled to form a cast product having a desired shape, such as a hollow shape or an undercut shape. When the molten metal cools, a thin wall is formed. By deforming the part and creating a gap between it and the cast product, defects such as deformation and damage of the cast product due to the influence of molten metal, etc. are prevented, and a hollow shape or undercut shape is formed. There is an advantage that it can contribute to the casting of shaped castings. (2) In addition to facilitating the formation of hollow shapes and undercut shapes, which are not possible with conventional die casting, it is also possible to use relatively large or complicated shapes such as engine intake manifolds and exhaust manifolds. Shape can be formed by die-cast casting Regardless of shape or size, casting of all shapes and sizes is possible, and deformation of the cast product due to the influence of the molten metal when cooling the molten metal after pressure pouring There is an advantage that a casting product such as a die-cast casting product having a target shape such as a hollow shape or an undercut shape can be obtained by preventing the occurrence of problems such as damage and breakage. (3) The molding core has both the non-disintegrating property during molding and the disintegrating property after molding, and the surface of the molding core is not as rough as the conventional sand core. Since it is smooth, the inner surface such as hollow shape or undercut shape is formed into a smooth surface, so secondary processing such as machining for inner surface smoothing is not necessary, and molded product defects such as wear and damage of molded products occur It is possible to improve the performance of the product using the molded product by preventing the above. (4) By using a special core, core molding is facilitated, molding equipment is simplified, the number of processes is reduced, the core is not easily broken, and it is easy to handle. There is an advantage that it is possible to reduce time and cost. (5) The main components can be prevented from permeating into the molded product, and defective products can be prevented by preventing the occurrence of defects such as blowholes and shrinkage or molten metal insertion due to the adverse effect prevention, thereby improving yield and productivity. (6) The core used in the present invention can be reused by reworking, which has the effect of reducing material costs and preventing pollution. (7) When using a core filled with a filler inside, the core is required to have conditions such as pressure resistance and heat resistance with the inside filled with a filler. Conditions such as pressure resistance and heat resistance are relaxed, the selection range of the core material can be expanded, and there is an advantage that the pressure resistance and heat resistance of the core can be adjusted by selecting the filling body. (8) When using a core filled with a filler, the hollow body is removed and lost by residual heat or heating and only the filler remains, so that the filler can be easily discharged and the core can be completely removed. There is an advantage that defects such as wear and damage of the product can be prevented.

The special molding core of the present invention is not limited to the die-cast casting of the above-described embodiment, but can be applied to gravity casting and other casting methods, as well as plastic molding, ceramic molding and other molding methods. , It is possible to obtain the same excellent effects as the above-mentioned die casting and other casting methods, and it is possible to mold all shapes and sizes without being restricted by shape, the range of application is greatly expanded, and the degree of freedom in design is improved. , Can form a wide range of molded products efficiently, dramatically improve the productivity, and can significantly reduce the cost by reducing the weight, etc., and it is excellent in the quality of forming hollow shapes and undercut shapes. It is possible to efficiently obtain a molded product having a desired shape.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molding die formed using a molding special core of a first embodiment according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which a molded product is molded by injecting a molding material into a molding die formed using the molding special core of the first embodiment according to the present invention.

FIG. 3 is a cross-sectional view showing a molded product molded by using a molding die formed by using the molding special core of the first embodiment according to the present invention.

FIG. 4 is a longitudinal sectional view showing a special molding core according to the first embodiment of the present invention.

FIG. 5 is a transverse sectional view showing the molding special core.

FIG. 6 is a cross-sectional view showing a deformed state of the special molding core during molding.

FIG. 7 is a cross sectional view showing a special molding core according to a second embodiment of the present invention.

FIG. 8 is a transverse sectional view showing a special molding core according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a special molding core according to a fourth embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a deformed state of the special molding core during molding.

FIG. 11 is a transverse sectional view showing a special molding core according to a fifth embodiment of the present invention.

FIG. 12 is a vertical sectional view showing a special molding core according to a sixth embodiment of the present invention.

FIG. 13 is a cross-sectional view showing the molding special core.

FIG. 14 is a sectional view of a special molding core according to a sixth embodiment of the present invention, which corresponds to FIG.

FIG. 15 is a sectional view showing a special molding core and a intake manifold that is a molded product according to a seventh embodiment of the present invention.

FIG. 16 is a sectional view showing a special molding core and an exhaust manifold which is a molded product according to an eighth embodiment of the present invention.

[Explanation of symbols]

1 Special core for molding (Special core for casting) (Special core for plastic molding) (Special core for ceramic molding) 2 Upper mold (mold) (outer mold) 3 Lower mold (mold) (outer mold) ) 4 Mold (mold) (Plastic mold) (Ceramic mold) 5 Cavity (Casted product shape) (Plastic molded product shape) (Ceramic molded product shape) 6 Molded product (Casted product) (Plastic molded product) ( Ceramic molded product) S Hollow part (filling space) G Main body (heat resistant main body) H Filler N Local thin-wall forming part L Length of thin-wall forming part t Thickness of thin-wall forming part T Thickness of non-thin-wall forming part C Hollow shape U Undercut shape E Exhaust manifold I Intake manifold

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29C 33/38 9543-4F 33/48 9543-4F

Claims (21)

[Claims] 1. A molding core used for forming a hollow shape, an undercut shape, or the like into a molded product such as a cast product, a plastic molded product, or a ceramic molded product. It is formed from a sand core, and a space is formed inside the molding core, and part or all of the wall thickness of the molding core is formed to have a non-uniform thickness. Special core for molding characterized by the following. 2. The molding core according to claim 1, wherein the molding core has a non-uniform thickness in all. 3. The molding core according to claim 1, wherein a part of the wall thickness of the molding core is formed to have a non-uniform thickness. 4. The molding core according to claim 3, wherein a part of the wall thickness of the molding core is locally thinned. 5. The special molding core according to claim 4, wherein the locally formed thin wall is formed by thinly forming a predetermined length substantially uniformly. . 6. The special molding core according to claim 4, wherein the locally formed thin wall is formed by forming a thin wall having a non-uniform predetermined length. . 7. The molding special core according to any one of claims 4 to 6, wherein the thin wall is locally formed at one location. 8. The special molding core according to claim 4, wherein the thin wall is locally formed at a plurality of locations. 9. The non-sand core is one that satisfies both conditions of non-disintegration during molding (heat resistance) and disintegration after molding (heat disintegration, solvent disintegration, etc.). The special molding core according to any one of claims 1 to 8. 10. The special molding core according to claim 9, wherein the non-sand core is made of a heat resistant material. 11. The molding special core according to claim 10, wherein the heat resistant material is made of heat resistant rubber such as silicone rubber. 12. The molding special core according to claim 10, wherein the heat resistant material is made of synthetic resin (plastic). 13. The special molding core according to claim 12, wherein the synthetic resin (plastic) is a thermosetting synthetic resin (thermosetting plastic). 14. The molding special core according to claim 12, wherein the synthetic resin (plastic) is a thermoplastic synthetic resin (thermoplastic). 15. The special molding core according to claim 14, wherein the thermoplastic synthetic resin (thermoplastic) is a polycarbonate synthetic resin (polycarbonate plastic). 16. The non-sand core comprises a main body having a space formed therein, and a filling body filled inside the main body. Further, a part or all of the thickness of the main body is The special molding core according to any one of claims 1 to 15, wherein the special molding core has a non-uniform thickness. 17. The molding special core according to claim 16, wherein the filling body is made of a heat-resistant material such as powder, granules or lumps. 18. The molding special core according to claim 17, wherein the heat resistant material is an inorganic material such as gravel of river, sea or mountain. 19. The molding special core according to claim 18, wherein the inorganic material is ceramic. 20. The special molding core according to claim 18, wherein the inorganic material is foundry sand. 21. The molding special core according to any one of claims 16 to 20, wherein the filler is mixed with powdery, granular, or lumpy metal.