JPH0768367A - Method for casting metal - Google Patents

Abstract

PURPOSE:To provide a method for casting metal where the prescribed pressurizing effect can be obtained even when a pressurizing pin is pressed into another thick wall part of the product which is not the thick wall part necessitating the pressing of the pressurizing pin most, or where there are no fears that the pressurizing effect by the pressing is not obtained or cracks are generated in the cast products even when the timing of pressing the pressurizing pin is slightly deviated. CONSTITUTION:In the method for casting meal where a pressurizing pin 4 is pressed into a thick wall part S1 of the cast product under the condition that the molten metal filled in the cavity is slightly solidified in casting a product (S) by filling the molten metal in a cavity 3 of dies 1, 2, the pressurizing pin is pressed into the thick wall part of the product in the heated condition, or the pressurizing pin is pressed into the thick wall part of the product while heating the periphery of the thick wall part of the product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to die casting,
When casting a product by filling molten metal into the cavity of a mold, when the molten metal filled in the cavity is somewhat solidified, a pressure pin is pushed into the thick part of the cast product. It concerns the improvement of the law.

[0002]

2. Description of the Related Art When casting a product by a die casting method or the like, the molten metal filled in the cavity of the die solidifies from the contact surface with the die. It is known that if there is such a difference, the thick portion of the product becomes the final solidified portion, so that a porosity is likely to occur in the thick portion of the product due to solidification shrinkage.

As a measure against this, conventionally, as shown in FIG. 3, in a state where the molten metal filled in the cavities 3 of the molds 1 and 2 is slightly solidified, the thick portion of the cast product S is supplemented by the solidification shrinkage. A casting method in which the pressure pin 4 is pushed into S ₁ is adopted.

However, even if one intends to adopt this conventional method, depending on the shape of the cast product and the restrictions of the casting apparatus, it is necessary to push the pressure pin into the product thick portion (final solidification portion). In some cases, the pressure pin could not be pushed in.

Moreover, in this conventional method, when the pressing pin 4 is pushed into the thick portion S ₁ of the cast product S, the pressing pin 4 is pushed while breaking the solidified layer m advancing from the contact surface with the die. Therefore, if the chill layer of the molten metal forming the thick part S _{1 of the} product is destroyed and a sound metal structure cannot be obtained, or if the timing of pressing the pressing pin is slightly shifted, the pressing effect due to the pressing is exerted. There were problems such as not being able to obtain sufficient results, and in some cases cracking of the cast product.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the conventional method, and the product that most requires the pressing of the pressure pin due to the shape of the cast product and the restrictions of the casting apparatus. Even if the pressure pin is pushed into a thick part of another product that is not a thick part, the predetermined pressure effect can be obtained, and even if the timing of pressing the pressure pin is slightly shifted, the pressure effect due to the pushing can be achieved. It is an object of the present invention to provide a metal casting method that is free from the fear of not being obtained or cracking of a cast product.

[0007]

The metal casting method according to claim 1 of the present invention which achieves the above object, is to fill a cavity of a mold with molten metal to cast a product in the cavity. In the metal casting method in which the pressure pin is pushed into the thick portion of the cast product when the filled molten metal is slightly solidified, the pressure pin is pushed into the thick portion of the product while being heated. The metal casting method according to claim 2 is characterized in that the pressing pin is pushed into the thick product portion while heating the periphery of the thick product portion. Further, in the metal casting method according to claim 3, the mold of the portion for molding the product thick portion is made of ceramics or the like having a high heat insulating property, and the pressing pin is formed on the product thick portion. It is characterized by being pushed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to claim 1 of the present invention will be described below with reference to FIG.

In the figure, 1 is a movable die, 2 is a fixed die, and a cavity 3 formed by the movable die 1 and the fixed die 2 is filled with a molten metal from an injection sleeve or the like (not shown) to produce a product. It is for casting S.

Then, a pin insertion hole 5 is formed at a position corresponding to a portion on the movable die 1 side or the fixed die 2 side (the fixed die 2 side in the illustrated embodiment) where the thick portion S ₁ of the cast product S is formed. Then, the pressure pin 4 is installed in the pin insertion hole 5 so as to be retractable with respect to the cavity 3.

[0011] pressurizing pin 4 is one molten metal that pulling the product thickness portion S ₁ capable pushed in slightly solidified state to compensate for solidification shrinkage of the product thickness portion S _1, a metal material Is formed into a round bar shape having a required diameter or a desired shape, and is installed in the cavity 3 in the pin insertion hole 5 of the mold by the same mechanical means as the conventional one, and at the same time, is appropriately formed. A mechanical means is used to heat the molds 1 and 2 to a temperature slightly higher than the mold temperature, and the heated product is pushed into the thick portion S ₁ of the cast product S.

As a mechanism for heating the pressure pin 4,
A method in which a heating source is brought into contact with a part of the pressure pin 4 to heat it by heat conduction from the heating source, or a heating chamber 4a is formed in the pressure pin 4 in the axial direction as in the illustrated embodiment.
It is conceivable that a heating oil or heating water as a heating source is circulated in the heating chamber 4a, or a mechanism means for heating the pressurizing pin 4 by installing a heater 4b therein.

When the pressure pin 4 is installed in the pin insertion hole 5 of the mold, a gap 6 is provided between the pressure pin 4 and the pin insertion hole 5 so that the heat insulating material 7 is interposed therebetween. Due to
The heat of the heated pressurizing pin 4 will not be carelessly taken by the mold 2.

When molten metal is filled in the cavities 3 of the molds 1 and 2, solidification of the molten metal in the cavities 3 proceeds from the contact surface with the molds 1 and 2, but the thick part of the product in a state where the molten metal is slightly solidified portion forming a S _1, to compensate for solidification shrinkage of the product thickness portion S ₁ of the pressure pin 4 at I pushed into the product thick portion S _1.

At this time, when the pressure pin 4 is pushed into the thick portion S _{1 of the} product, the temperature of the pressure pin 4 is kept from before the push-in to the molds 1 and 2.
Press the pin 4 by heating it to a temperature slightly higher than the mold temperature.
After the solidification of the molten metal in the vicinity is delayed a little more than the other parts, and after the pressing is completed, the temperature of the pressing pin 4 is lowered to the mold temperature of the molds 1 and 2, and the solidification of the thick product portion S ₁ is completed. The pressure pin 4 is pulled out from the product thick portion S ₁ .

Next, an example of an embodiment according to claim 2 of the present invention will be described with reference to FIG. 2. The same members as the constituent members according to claim 1 of the present invention described above are designated by the same reference numerals as in FIG. The description is omitted.

In the metal casting method according to the second aspect of the present invention, the pressure pin 4 is pushed into the thick product portion S ₁ while heating the periphery of the thick product portions S ₁ and S ₂ . That is,
Product thickness portion S ₁ on the movable die 1 side or the fixed die 2 side,
A heater installation hole 8 is formed around the portion forming S ₂ , and heating oil or heating water as a heating source is circulated in the heater installation hole 8 or a heating heater 9 is installed as in the illustrated embodiment. Then, the periphery of the product thick portions S ₁ and S ₂ is heated, and the pressing pin 4 is pushed into the product thick portion in that state.

At this time, if there are two or more product thickness portions S ₁ and S ₂ as in the illustrated embodiment, or the shape of the cast product S and the restrictions of the casting apparatus, the pressure pin 4 is partially used as the product meat. If the thickness portion which can not be disposed only in S _1, the product thickness portion S ₁ and S ₂ around as the product inside the thick portion S ₁ is the final solidified portion of the pressure pin 4 can pushing it Control the heating of.

Even when the pressure pin 4 is pushed into the thick product portion S ₁ while heating the periphery of the thick product portions S ₁ and S ₂ , the casting method according to the above-mentioned claim 1 is used. Similarly, the pressure pin 4 may be heated and pushed in.

Further, in the metal casting method according to claim 3 of the present invention, the metal molds ₁ , ₂ of the portions for molding the product thick portions S ₁ , S ₂ are used.
By forming ceramics with high heat insulation,
When the pressure pin 4 is pushed into the product thickness portions S ₁ and S ₂ , the solidification of the molten metal in the vicinity of the pressure pin 4 is delayed a little compared to other portions.

[0021]

In the metal casting method according to the first aspect of the present invention, the pressure pin is pushed into the thick portion of the product while being heated. Therefore, at least the pressure pin is provided in the vicinity of the pressure pin. The molten metal in the contacting portion is slower to solidify than other portions, and as a result, when the pressure pin is pushed into the thick portion of the product, the solidified layer m advancing from the contact surface with the mold is formed. It will not be pushed in while breaking.

Moreover, since the final solidification is in the vicinity of the heated pressure pin, even if the timing of pressing the pressure pin is slightly shifted, the pressure effect due to the pressing cannot be obtained or the cast product is cracked. There is no fear of occurrence.

Further, according to the metal casting method of the second aspect of the present invention, since the pressure pin is pushed in while heating the periphery of the product thick portion, the outside of the heated product thick portion (gold). The molten metal in the part that is in contact with the mold is slower to solidify than the other parts, and as a result, the solidification is proceeding from the contact surface with the mold when the pressure pin is pushed into the thick part of the product. Layer m
There is no need to push while breaking.

In addition, when there are two or more product thick parts, or due to the shape of the cast product or the restrictions of the casting equipment, the pressing of the pressure pin is added to another product thick part which is not the most necessary. Even if you have to press the pressure pin, it is possible to control the heating of the product thickness part so that the inside of the product thickness part where the pressure pin can be pressed becomes the final solidification part. You can expect an effect.

Further, according to the metal casting method of the third aspect of the present invention, since the mold of the portion for forming the product thick portion is made of ceramic or the like having a high heat insulating property, the molten metal of the product thick portion is formed. Solidifies more slowly than other parts, and therefore, when the pressure pin is pushed into the thick portion of the product, the solidification layer m advancing from the contact surface with the mold is not pushed in while breaking.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of an embodiment according to claim 1 of the present invention.

FIG. 2 is a schematic sectional view showing an example of an embodiment according to claim 2 of the present invention.

FIG. 3 is a schematic sectional view illustrating a conventional method.

[Explanation of symbols]

1: Movable type 2: Fixed type 3: Cavity 4: Pressurizing pin 5: Pin insertion hole 4a: Heating heater 6: Gap 7: Insulating material 8: Heater installation hole 9: Heater for heating S: Cast product S ₁ : Product Thick part m: Solidified layer

Claims (3)

[Claims] 1. When a molten metal is filled in the cavity of a mold to cast a product, a pressurizing pin is provided in the thick portion of the cast product in a state where the molten metal filled in the cavity is slightly solidified. In the metal casting method that was pushed in,
A metal casting method characterized in that the pressure pin is pushed into the thick portion of the product while being heated. 2. When a molten metal is filled in the cavity of a mold to cast a product, a pressure pin is provided in the thick portion of the cast product in a state where the molten metal filled in the cavity is slightly solidified. In the metal casting method that was pushed in,
A metal casting method characterized in that a pressure pin is pushed into the product thick portion while heating the periphery of the product thick portion. 3. When a molten metal is filled in the cavity of a mold to cast a product, a pressure pin is provided on the thick portion of the cast product in a state where the molten metal filled in the cavity is slightly solidified. In the metal casting method that was pushed in,
A metal casting method, characterized in that a mold of a portion for forming the product thick portion is formed of ceramics or the like having a high heat insulating property, and the pressing pin is pushed into the product thick portion.