JPS6289560A - Die casting method - Google Patents

Abstract

PURPOSE:To reduce the cycle time of die casting by providing a porous member for removing oxide consisting of an electrical heating element near a sprue part and energizing the porous member since the start of casting until the molten metal in a cavity solidifies. CONSTITUTION:A metallic mold 8 is imposed on a cap 4 of a holding furnace 1. A wire net 13 for removing oxide, etc. coated with an insulator 14 is installed between the sprue part in the lower part of a drug 10 and a ring member 12 fixing a stoke 5. The net 13 is kept electrically heated during the time since the pouring of the molten metal 3 in a crucible 2 via the stoke 5 into the product cavity 11 is started until the molten metal 3 in the cavity 11 solidifies, in the stage of casting. The remaining unsolidified metal 3 is dropped into the crucible 2 when the molten metal 3 in the cavity 11 solidifies in this casting method. The wire net is thereby made repeatedly usable and the cycle time for die casting is reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a mold casting method, and in particular, a method in which molten metal is injected from below into a product cavity defined by a mold, and the molten metal in the product cavity solidifies. The present invention also relates to a casting method suitable for low-pressure casting, suction casting, etc. in which the remaining unsolidified molten metal is dropped.

[Conventional technology]

Conventionally, in mold casting, especially low-pressure casting, in which molten metal is poured into a product cavity defined by a mold from a lower holding furnace through a stalk, etc., It is necessary to prevent oxides, dirt (dust), etc. present in the product from entering the product cavity. However, since oxides and dust have a lower specific gravity than the molten metal, when introduced into the carrier stalk, they are preferentially guided into the product cavity, resulting in a deterioration in the quality of the casting. Therefore, conventionally, a wire mesh has been attached to a draft part, for example, near a sprue part, in order to prevent such oxides and dirt from entering the product cavity and to rectify the water flow.

[Problem that the invention seeks to solve]

However, since this wire mesh becomes integrated with the cast raw material as the molten metal solidifies, it is necessary to install the wire mesh for each casting. Therefore, there is a problem in that not only a large number of wire meshes are required, but also it takes time to install the wire mesh. Furthermore, since the wire mesh installation work is carried out under high temperatures, the working environment is not favorable. Furthermore, when attaching the wire mesh, the coating material applied to the mold surface may be damaged. Furthermore, when melting and reusing design parts such as sprues and runners, if the molten metal is a light metal such as an aluminum alloy, the iron content in the molten metal will be high and the quality of the casting material will deteriorate. It had to be removed beforehand.

Therefore, in the mold casting method, it has been desired to develop a method that allows the wire mesh for removing oxides and dust to be used repeatedly.

[Means for solving problems]

The above problem is solved by the mold casting method of the present invention, which will be described below.

That is, the mold casting method of the present invention is a mold casting method in which molten metal is injected from below into a product cavity defined by a mold, and after the molten metal in the product cavity has solidified, the remaining unsolidified molten metal is dropped. In the mold casting method, a porous member for removing oxides, etc. is installed near the sprue leading to the product cavity, and the porous member consists of a heating element, and the porous member is installed in the product cavity from the start of casting. The porous member is characterized by being energized until the molten metal solidifies.

The porous member used in the present invention needs to be made of a substance that has excellent heat resistance and corrosion resistance and generates heat when energized, and for example, tungsten, molybdenum, etc. can be used.

A wire mesh, punched metal, or the like can be used as this porous member. When these porous members are installed in a mold, it is necessary to cover the periphery of the porous member with an insulator such as ceramics.

Further, in order to improve corrosion resistance against molten metal, ceramics may be thermally sprayed onto the surface of the porous member.

The size of the porous member may be such that it can completely cover the passage of the molten metal to be installed, and the shape may be circular or rectangular.

[Effect]

According to the mold casting method of the present invention, since the porous member is energized during casting, the porous member generates heat during the energization. Therefore, the molten metal in the vicinity of the porous member is always in a molten state, and a sufficient feeder effect can be provided until the molten metal in the product cavity solidifies.

Furthermore, if the pressurization of the molten metal is stopped after the molten metal in the product cavity has solidified, the molten metal below the vicinity of the porous member will fall into a holding furnace, etc., and the solidified part above the porous member and the product part will be integrated. It is released from the mold.

Therefore, the porous member can be used again as it is. As a result, there is no need to install a porous member for each casting, damage to the coating material can be prevented, and furthermore, the reprocessing of the patterned part becomes easy.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

This example shows an example in which the present invention is applied to a low pressure casting method.

Here, FIG. 1 is a schematic configuration diagram showing one step of the low-pressure casting method according to an embodiment of the present invention, FIG. 2 is an enlarged view of part A in FIG. 1,
FIG. 3 is a view in the direction of arrow B in FIG. 2, and FIG. 4 is a plan view showing the wire mesh used in the embodiment of the present invention.

In FIG. 1, 1 is a holding furnace that holds a crucible 2. A molten aluminum alloy (hereinafter simply referred to as molten metal) 3 is held within this crucible 2 . A furnace IE4 which also serves as a die base is placed above the crucible 2, and the crucible 2 and the furnace cover 4 form a substantially sealed space. A stepped hole 6 for inserting and supporting the stalk 5 is provided in the center of the furnace lid 4, and an intake and exhaust hole 7 for pressurizing the inside of the holding furnace 1 and exhausting the inside of the holding furnace 1.
is formed. This intake/exhaust hole 7 is connected to pressurized gas supply means (not shown).

A mold 8 is placed on the top of the furnace lid 4.

This mold 8 consists of an upper mold 9 and a lower mold lO.
A product cavity 11 is defined by the lower mold 10. Further, a ring member 12 is provided at the lower part of the lower mold 10, and presses and fixes the stalk 5 to the furnace lid 4. The other end of the stalk 5, which is partially fixed to the furnace lid 4, is provided to extend to near the bottom of the furnace. This stalk 5 usually has a cylindrical shape with a flange.

Further, as shown in FIGS. 1 to 3, a wire gauze 13 as a porous member is disposed in the sprue portion of the lower part of the lower mold 10. As shown in FIGS. The wire mesh 13 is protected around the wire by an insulator 14 made of ceramic, and is connected to an electric wire R17 via a switch 16 by a pair of lead wires 15.

Next, the operation will be explained.

First, after the mold is clamped to define the product cavity 11, compressed air is blown into the furnace from a pressurized gas supply means (not shown) through the intake and exhaust holes 7. Then, the molten metal 3 in the furnace is pressurized and injected into the product cavity 11 via the stalk 5. At the same time as this pressurization, the switch 16 of the power supply 17
and energize the wire mesh 13. After the molten metal in the product cavity 11 has solidified, the air is exhausted from the suction/exhaust hole 7, and the switch 16 is turned off to stop energization. As a result, the molten metal 3 in the stalk 5 falls into the holding furnace 1.

Subsequently, the mold is released in the usual manner and the product (casting) is taken out.

In this embodiment, since the solidified part such as the product part and the unsolidified molten metal are separated through the wire mesh 13, the wire mesh 13 can be used as many times as is.

In addition, the obtained castings (products) were in good condition with no casting defects such as hollow holes.

Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but includes various embodiments within the scope of the claims.

For example, in the example, a wire mesh was used as the porous member, but as shown in Figs. You may also use one rolled into a shape.

〔Effect of the invention〕

As described above, according to the mold casting method of the present invention, the following effects are achieved.

(a) Porous members can be used repeatedly. Therefore, it is not necessary to install a wire gauze for each casting as in the conventional method, so damage to the coating material can be prevented and the casting cycle can be shortened by the time required to install the porous member. In addition, workability is improved because high-temperature work for installing the porous member is almost eliminated.

(b) During casting, since the porous member is energized, the molten metal in the vicinity of the porous member is in a molten state, and a sufficient feeder effect can be provided within the product cavity.

Therefore, casting defects such as cavities are reduced, and the quality of the casting can be improved.

(c) Since the product part and the design part are separated near the porous member, post-processing becomes easier and the yield is improved. In addition, since the porous member does not solidify together with the pattern part, the molten metal treatment when the pattern part is melted again and reused becomes easy.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing one step of the low-pressure casting method according to the embodiment of the present invention, Fig. 2 is an enlarged view of part A in Fig. 1, and Fig. 3 is an arrow shown in Fig. 2 when viewed from direction B. The perspective view, FIG. 4, is a plan view showing the wire mesh used in the embodiment of the present invention. FIG. 5 is a plan view showing another example of the porous member used in the present invention, and FIG. 6 is a plan view showing still another example of the porous member used in the present invention. 1-----...Holding furnace 2--Luppo 3--Molten metal 4--Furnace lid 5--Stoke 6--Single hole? ----- To - Intake/exhaust hole 8...--1--Mold 9...--Upper mold 10--Lower mold 11--Product cavity 12... -・-Ring member 13--1111 Wire mesh (porous member) 14--
--Insulator 15--111 Lead wire 16--Switch 17--Power supply Applicant Toyota Motor Corporation Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] (1) A mold casting method in which molten metal is injected from below into a product cavity defined by a mold, and after the molten metal in the product cavity has solidified, the remaining unsolidified molten metal is dropped into the product cavity. A mold casting method in which a porous member for removing oxides, etc. is installed near a sprue that leads to the sprue, and the porous member consists of a heating element, and the porous member is used for the period from the start of casting until the molten metal in the product cavity solidifies. , a mold casting method characterized by energizing this porous member.