JP2009297764A - Casting device and casting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the technique which can easily draw out a pressure pin after a molten metal is solidified. <P>SOLUTION: The casting device 10 is provided with a mold 12, a pressure pin 14 and a spray 26. The mold 12 includes a product cavity 22. The pressure pin 14 is provided so as to be progressed/retreated to the product cavity 22. The spray 26 sprays a mold releasing agent 24 comprising a shrinkage suppression material suppressing the shrinkage of a molten metal upon solidification by being melted in the molten metal toward the pressure pin 14, so as to allow the shrinkage suppression material to stick around the pressure pin 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a casting apparatus. In particular, the present invention relates to a casting apparatus having a pressure pin that is pushed into a molten metal poured into a product cavity of a mold.

  Since the molten metal in the product cavity shrinks during solidification, an unfilled portion called a so-called shrinkage nest may occur in the product after casting. In order to prevent this shrinkage, a technique is used in which a pressure pin is pushed into the molten metal in the product cavity to pressurize the molten metal during solidification. The pressure pin is pulled out from the product after the melt has solidified and the product has been molded. However, since the molten metal contracts during solidification, the pressure pin is firmly held by the molten metal, and the pressure pin may be difficult to come off. A technique for solving this problem is disclosed in Patent Document 1, for example.

  In the casting apparatus described in Patent Document 1, a discarding member is attached to the tip of the pressure pin. The throwaway member is detachably attached to the pressure pin. In this casting apparatus, the pressure pin is pushed toward the molten metal together with the disposal member. After the molten metal solidifies and the product is molded, the discard member is discarded in the product, and only the pressure pin is pulled out of the product. In this casting apparatus, even if the molten metal contracts during solidification, the pressure pin is not gripped by the molten metal, and the pressure pin does not easily come off.

JP 2002-254155 A

  Patent Document 1 describes that the discard member is formed using the same metal material as the cast metal. In this case, there is a possibility that the discarded member is melted in the molten metal. When the throwaway member melts, the throwaway member contracts during solidification, and the pressure pin is firmly held. This makes it difficult for the pressure pin to come off.

  This invention is made | formed in view of the situation mentioned above, and provides the technique which can draw out a pressurization pin easily after a molten metal solidifies.

  The present invention provides a casting apparatus for achieving the above object. The casting apparatus of the present invention includes a forming die, a pressure pin, and an attaching means. The mold has a product cavity. The pressure pin is provided in the product cavity so as to be able to advance and retract. The adhering means adheres to the pressure pin a shrinkage suppression material that suppresses shrinkage when the molten metal is solidified by melting in the molten metal.

  In this casting apparatus, shrinkage cavities can be prevented from being generated by pressing the pressure pin into the molten metal in the product cavity and pressurizing the molten metal during solidification. At this time, a shrinkage suppression material can be adhered to the pressure pin, and the molten metal around the pressure pin can be prevented from shrinking during solidification. Thereby, after a molten metal solidifies and a product is shape | molded, a pressurization pin can be pulled out easily.

The shrinkage-suppressing material described above contains a shrinkage-reducing substance that lowers the shrinkage rate during solidification (the degree of shrinkage during solidification) of the molten material at a higher concentration than the molten material, as the molten material contains a higher concentration. It is preferable.
In this configuration, the concentration of the shrinkage-reducing substance in the melt around the pressure pin is increased by melting the shrinkage-lowering substance in the melt around the pressure pin. As a result, the shrinkage rate at the time of solidification of the molten metal around the pressure pin decreases. Thereby, after a molten metal solidifies and a product is shape | molded, a pressurization pin can be pulled out easily.
For example, when the main material of the molten metal is aluminum, the shrinkage reducing substance is preferably silicon.
Since silicon is a material generally added to an aluminum alloy, even if silicon remains in the product after casting, the quality of the product is not deteriorated.

The present invention also provides a new and useful casting method in order to achieve the above object. The casting method of the present invention includes a step of attaching a shrinkage-suppressing material that suppresses shrinkage at the time of solidification of the molten metal by melting the molten metal on a pressure pin that can advance and retreat with respect to the product cavity, and a shrinkage-suppressing material. A step of pressing the pressed pin into the molten metal in the product cavity.
According to this casting method, similarly to the above-described casting apparatus, the shrinkage suppressing material suppresses the molten metal around the pressure pin from shrinking during solidification. Thereby, after a molten metal solidifies and a product is shape | molded, a pressurization pin can be pulled out easily.

  According to the present invention, shrinkage at the time of solidification of the molten metal around the pressure pin is suppressed. Thereby, when pulling out the pressure pin, the product and the pressure pin can be prevented from being damaged.

The technical features of the following examples are listed.
(Form 1) The shrinkage-suppressing material is contained in a release agent.
(Mode 2) The shrinkage-suppressing material is attached to the pressure pin by attaching the release agent to the pressure pin.

  A casting apparatus according to an embodiment embodying the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the casting apparatus 10. FIG. 2 is a longitudinal sectional view showing a state of the casting apparatus 10 before the molten metal is supplied to the casting apparatus 10. The casting apparatus 10 casts an aluminum alloy. The main material of the molten metal is aluminum and contains approximately 9% silicon. As shown in FIG. 1, the casting apparatus 10 includes a mold 12, a pressure pin 14, and a spray 26. The mold 12 has an upper mold 16 and a lower mold 18. The lower surface of the upper die 16 and the upper surface of the lower die 18 are processed so as to correspond to the product shape.

  The pressure pin 14 is inserted into a through hole 16 a formed in the upper mold 16. The pressure pin 14 is arranged to be movable in the axial direction of the through hole 16a. The pressure pin 14 has a cylindrical shape. The diameter of the pressure pin 14 is substantially the same as the inner diameter of the through hole 16a. For this reason, the molten metal is prevented from entering between the pressure pin 14 and the through hole 16a. The spray 26 sprays the release agent 24 around the pressurizing pin 14 and attaches the release agent 24 around the pressurizing pin 14. As the release agent 24, for example, an emulsion release agent can be used. The release agent 24 includes a shrinkage suppression material that suppresses shrinkage of the molten metal during solidification. The shrinkage suppression material is an Al-15% Si alloy powder. The silicon concentration of the shrinkage suppression material is higher than the silicon concentration of the molten material. The powder of the Al-15% Si alloy has a particle size of 30 to 60 μm. The release agent 24 attached to the periphery of the pressure pin 14 has a thickness of approximately 0.2 mm.

  As shown in FIG. 2, a core 20 is inserted into a space formed by combining the upper mold 16 and the lower mold 18. The core 20 has a cylindrical shape. The core 20 is arranged to be movable in the axial direction of the core 20 with respect to the mold 12. A core 20 is arranged in a space formed by the upper mold 16 and the lower mold 18 being combined, and a product cavity 22 is formed.

  Next, the casting method of a present Example is demonstrated. FIG. 3 is a flowchart showing the procedure of the casting method. First, as shown in FIG. 1, in a state where the upper mold 16 and the lower mold 18 are separated from each other, the spray 26 injects a release agent 24 around the pressure pin 14 and around the pressure pin 14. A release agent 24 is adhered (step S12). Subsequently, the upper die 16 and the lower die 18 are matched (step S14). As shown in FIG. 2, the core 20 is inserted into a space formed by combining the upper mold 16 and the lower mold 18 (step S16). Thereby, the product cavity 22 is formed. The molten metal 23 is injected into the formed product cavity 22 (step S18). When a predetermined time (for example, a time for which the thin portion 23b is substantially solidified) has elapsed after the molten metal 23 is injected (YES in step S20), the pressure pin 14 is pushed into the molten metal 23 in the product cavity 22 (step S22). Thereby, the pressurizing pin 14 pressurizes the thick portion 23 a of the molten metal 23 in the product cavity 22, and shrinkage cavities generated by contraction of the molten metal 23 during solidification can be prevented.

  When a predetermined time (for example, the time for the entire molten metal to solidify) elapses after the pressurizing pin 14 is pushed into the molten metal (step S24), the pressurized pin 14 is pulled out from the solidified molten metal (product) and is inserted into the through hole 16a. Withdraw (step S26). Further, the core 20 inserted into the product cavity 22 is pulled out (step S28). Subsequently, the upper die 16 and the lower die 18 are separated (step S30), the product is taken out from the mold 12 (step S32), and the casting is finished.

  When the pressure pin 14 comes into contact with the molten metal, the shrinkage suppression material attached to the pressure pin 14 is melted into the molten metal. As a result, an aluminum alloy having a silicon concentration higher than that of the molten material is present around the pressure pin 14. Silicon is a shrinkage-reducing substance that lowers the shrinkage rate at the time of solidification of a molten material as it is contained in an aluminum alloy that is a molten material at a higher concentration. Therefore, the shrinkage | contraction at the time of solidification of the molten metal around the pressurization pin 14 can be suppressed. Thereby, after the molten metal 23 is solidified and the product is molded, the pressure pin 14 can be easily pulled out.

  In the casting apparatus 10 described above, an Al-15% Si alloy is used as the shrinkage suppression material. However, the concentration of silicon contained in the shrinkage suppression material is not limited to 15% as long as it is higher than the concentration of silicon in the molten material. Furthermore, the shrinkage suppression material is not limited to an aluminum alloy, and may be a silicon simple substance.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the casting apparatus 10 described above, the release agent 24 containing the shrinkage suppression material is automatically attached around the pressure pin 14 by the spray 26 installed in the casting apparatus 10. However, the operator may attach the shrinkage suppression material around the pressure pin 14.
In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The longitudinal cross-sectional view which shows the casting apparatus of a present Example. The longitudinal cross-sectional view which shows the casting apparatus before a molten metal is inject | poured in a product cavity. The flowchart which shows the procedure of a casting method. The longitudinal cross-sectional view which shows a casting apparatus when the pressurization pin is pushed into the molten metal in a product cavity.

Explanation of symbols

10: Casting device 12: Mold 14: Pressure pin 22: Product cavity 26: Spray

Claims (4)

A mold having a product cavity;
A pressure pin provided so as to be capable of moving forward and backward with respect to the product cavity;
An adhesion means for attaching a shrinkage suppression material to the pressure pin that suppresses shrinkage during solidification of the molten metal by melting in the molten metal;
A casting apparatus comprising:   The shrinkage-suppressing material contains a shrinkage-reducing substance that lowers the shrinkage rate at the time of solidification of the melt as it is contained in the molten material at a higher concentration than in the molten material. The casting apparatus described. The main material of the molten metal is aluminum,
The casting apparatus according to claim 2, wherein the shrinkage reducing material is silicon. A step of attaching a shrinkage-suppressing material that suppresses shrinkage at the time of solidification of the molten metal by melting in the molten metal to a pressure pin that can advance and retreat with respect to the product cavity;
The process of pushing the pressure pin with the shrinkage-suppressing material attached into the melt in the product cavity,
A casting method comprising:

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