JPH0994649A - Method for die-casting aluminum alloy casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the elution of a synthetic resin-made core from a core print at the time of casting and to obtain a high quality aluminum casting without developing cold-shut, misrun and casting flash, etc., in a die casting method of the aluminum casting using the synthetic resin-made core in a die. SOLUTION: The die casting is executed in the condition of 50-150 deg.C die temp., 600-650 deg.C molten metal temp., 0.01-0.20sec filling time into a cavity and 10-60sec curing time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of die casting an aluminum (hereinafter referred to as "aluminum") alloy casting using a core in a mold, wherein the core is made of a synthetic resin and has a high complex shape. The present invention relates to a die casting method for obtaining a quality aluminum casting.

[0002]

2. Description of the Related Art Generally, a sand core is used to form a hollow portion or an undercut portion by casting. However, in the die casting method of filling the molten metal at a high speed, the strength of the sand core is insufficient, and the core is often broken by the molten metal pressure during casting. For this reason, it is difficult to use the sand core except in special cases.

[0003]

Therefore, as a core which can be used in die casting in recent years, Japanese Patent Laid-Open No. 6-9924 has been proposed.
As disclosed in Japanese Patent Laid-Open No. 7 and the like, a synthetic resin core such as polycarbonate has been proposed and partially used. This synthetic resin core has the advantages that it maintains strength against the molten metal pressure during casting, and can be easily removed by heating to approximately 200 to 300 ° C. after casting.

However, when die casting is actually performed using a synthetic resin core, there is a problem that the synthetic resin core is easily melted by the heat of the molten aluminum alloy injected into the cavity depending on the casting conditions. . When the synthetic resin core melts, the molten synthetic resin elutes from the skirting board and adheres to the mold. The attached synthetic resin does not peel off from the mold even when the die-cast product is taken out, and is gasified by the heat of the molten aluminum alloy during the next die-casting, causing a gas entrapment defect in the die-casting product or the surface of the next die-casting product. To adhere to. Furthermore, the synthetic resin attached to the mold creates voids on the parting surface, and the molten metal is inserted into the voids, which easily causes burrs. Since the synthetic resin attached to the mold is firmly attached, it cannot be easily removed even if it is attempted to be removed. To remove this, it is possible to cast several times without using a synthetic resin core and attach it to the casting, but with this, the yield to obtain an aluminum casting is low and the productivity is very high. Deteriorate.

For the purpose of preventing melting of the synthetic resin core,
It is possible to apply a heat insulating coating to the surface of a synthetic resin core, but a thin heat insulating coating has a small effect of preventing melting, and a thick heat insulating coating, on the contrary, makes it difficult to remove the core after casting. The present invention solves the above-mentioned conventional problems, and in a die casting method of an aluminum casting using a synthetic resin core in a mold, elution of the synthetic resin from the skirting board by melting the synthetic resin core during casting. It is an object of the present invention to obtain a high-quality aluminum casting that prevents the occurrence of hot water and prevents the occurrence of burr and the like.

[0006]

Means for Solving the Problems As a result of intensive studies made by the present inventors, in a die casting method using a synthetic resin core, a mold temperature, a molten metal temperature, a cavity filling time, and a curing time are set within a certain range. The inventors have found that the synthetic resin core is less likely to melt and is less likely to adhere to the mold when controlled to be the present invention. That is, according to the method of die casting an aluminum alloy casting using a synthetic resin core in the mold of the present invention, the mold temperature is 50 to 150 ° C. and the molten metal temperature is 6
The filling time into the cavity is 0.01 to 650 ° C.
It is characterized in that the curing time is 0.20 seconds and the curing time is 10 to 60 seconds.

[0007]

[Action]

(1) Mold temperature: 50 to 150 ° C. In casting, the heat of the molten metal is transferred to the mold during filling and solidification of the molten metal. The larger the amount of heat transferred to the synthetic resin core, the easier the synthetic resin core is to melt. In order to prevent the melting of the synthetic resin core, it is necessary to remove the heat of the filled aluminum alloy melt in a short time by the outer mold, that is, the mold.

When the mold temperature is lowered, the heat of the molten aluminum alloy is taken by the mold to suppress the temperature rise of the synthetic resin core. And the elution of the synthetic resin core is prevented. To prevent elution, the mold temperature must be 150 ° C or lower. On the other hand, if the mold temperature is too low, casting defects such as a hot water boundary and non-rotation will easily occur in the aluminum casting after casting. Therefore, the mold temperature should be 50 ° C or higher.

(2) Molten metal temperature: 600 to 650 ° C. The lower the molten metal temperature of the aluminum alloy to be die cast, the lower the calorific value of the molten metal and the temperature rise of the synthetic resin core. And the elution of the synthetic resin core is prevented. To prevent elution, the temperature of the molten aluminum alloy is 650 ° C or lower. On the other hand, if the molten metal temperature of the aluminum alloy is too low, defects such as the boundary between the molten metal and non-rotation tend to occur as in the case where the mold temperature is low. Therefore, the molten metal temperature is set to 600 ° C or higher.

(3) Cavity filling time: 0.01 to
0.20 seconds The shorter the filling time (injection time) into the mold cavity, the shorter the contact time between the synthetic resin core and the molten metal, and the lower the temperature rise of the synthetic resin core. Prevent the resin core from elution. To prevent this elution, the cavity filling time is within 0.20 seconds. On the other hand, if the filling time is too short, the molten metal inertial force becomes large and burrs are likely to occur on the parting surface. Therefore, the cavity filling time is 0.
It was set to 01 seconds or more.

(4) Curing time: 10 to 60 seconds The longer the curing time from filling the cavity with the molten aluminum alloy to opening the mold, the lower the temperature of the solidified cast product. It is possible to prevent elution of the synthetic resin core. It takes 10 seconds or more to prevent elution. On the other hand, if the curing time is too long, the cycle time becomes long and the productivity decreases. Therefore, the curing time is 60 seconds or less.

In a die casting method of an aluminum alloy casting using a synthetic resin core, the mold temperature is 50 to 150 ° C., the melt temperature is 600 to 650 ° C., and the cavity filling time is 0.
By setting 01 to 0.20 seconds and curing time to 10 to 60 seconds, it is possible to prevent casting defects such as elution of synthetic resin core, molten metal boundary, non-rotation and burrs, and cast high quality aluminum castings. It is possible to

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples. Figure 1 is based on the die casting method (J
IS) A displacement of 15 mm 3 mm thick made of ADC12 alloy
It is a figure which shows the manifold 1 for a 00cc 4-cylinder engine. Reference numeral 1 is a manifold, 2 is a synthetic resin core made of polycarbonate, and 3 is a skirting board at five locations. Then, die casting was performed while changing the mold temperature, the molten metal temperature, the cavity filling time and the curing time, and the presence or absence of elution of the synthetic resin core and the quality of the cast product were evaluated. Table 1 shows the survey results.

[0014]

[Table 1]

As shown in Example 1, the mold temperature was set to 150.
℃, melt temperature 650 ℃, cavity filling time 0.2
By setting 0 second and the curing time to 10 seconds, elution of the synthetic resin core can be prevented, and a good cast product without a hot water boundary can be obtained. In Example 2, the mold temperature and the curing time were the same as in Example 1, and the melt temperature was 600 ° C.
The cavity filling time is 0.10
When the time is set to 2 seconds, a synthetic resin core is not eluted and a good cast product can be obtained. In Example 3, the melt temperature and the curing time were the same as in Example 1, and the mold temperature was 50.
Cavity filling time is 0.1
By setting it to 0 seconds, there is no elution of the synthetic resin core,
A good cast product can be obtained. In Example 4, the curing time was the same as in Example 1 except that the mold temperature was lowered to 50 ° C. and the molten metal temperature was lowered to 600 ° C. A good cast product can be obtained without elution of the resin core. In Example 5, the mold temperature, the melt temperature and the cavity filling time were the same as in Example 1 and the curing time was 60 seconds, but the synthetic resin core did not elute and a good cast product was obtained. Obtainable.

On the other hand, in Comparative Example 1, the molten metal temperature and the cavity filling time were the same as in Example 1, but the mold temperature was raised to 180 ° C., but even if the curing time was 60 seconds,
Elution of the synthetic resin core has occurred. In addition, Comparative Example 2
However, the mold temperature and the cavity filling time were the same as in Example 1, but the one in which the molten metal temperature was raised to 670 ° C., the elution of the synthetic resin core occurred even when the curing time was 60 seconds. Further, in Comparative Example 3, the mold temperature, the molten metal temperature, and the cavity filling time were the same as those in Example 4, but the curing time was shortened to 5 seconds, and the synthetic resin core was eluted. Further, in Comparative Example 4, the molten metal temperature, the cavity filling time and the curing time were the same as those in Example 4, but the mold temperature was lowered to 40 ° C., but the synthetic resin core did not elute, but the bath boundary Is not a good cast product. Also,
In Comparative Example 5, the mold temperature, the cavity filling time and the curing time were the same as those in Example 4, but the molten metal temperature was lowered to 590 ° C., but the synthetic resin core did not elute, but a molten metal boundary occurred. It is not a good cast product. In addition, in Comparative Example 6,
The mold temperature, the melt temperature and the curing time were determined in Example 5.
In the same manner as above, with the cavity filling time set to 0.30 seconds, the synthetic resin core does not elute, but improper rotation occurs, which is not a good cast product. Further, in Comparative Example 7, the mold temperature, the molten metal temperature and the curing time were the same as those in Example 4 and the cavity filling time was shortened to 0.005 seconds, but the synthetic resin core did not elute, but the burr was not formed. Is not a good cast product.

[0017]

As described above in detail, according to the method of die casting an aluminum alloy casting using a synthetic resin core in the mold of the present invention, the mold temperature is 50 to 150 ° C. and the molten metal temperature is 600 to 650. ℃, 0.0 hours to fill the cavity
Since the curing time is 1 to 0.20 seconds and the curing time is 10 to 60 seconds, the temperature rise of the synthetic resin core is suppressed to a low level, the synthetic resin core is prevented from being eluted from the skirting part, and hot water is added. Border,
It is possible to obtain a high-quality aluminum cast product that does not generate non-rotation and burrs.

[Brief description of drawings]

FIG. 1 is a manifold for a four-cylinder engine before removing a synthetic resin core.

[Explanation of symbols]

1: Manifold, 2: Baseboard part, 3: Synthetic resin core.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location B22D 17/32 B22D 17/32 Z (72) Inventor Hiroshi Watanabe 5200 Mikageri, Kumagaya-shi, Saitama Hitachi Metals Incorporated company Mold Research Laboratory

Claims (1)

[Claims] 1. A method of die casting an aluminum alloy casting using a synthetic resin core in a mold, wherein the mold temperature is 50 to 150 ° C., the melt temperature is 600 to 650 ° C., and the cavity filling time is set. A die-casting method for an aluminum alloy casting, which comprises 0.01 to 0.20 seconds and a curing time of 10 to 60 seconds.