JP3281314B2 - Precision casting mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold used for precision casting in which a metal is melted by high-frequency induction heating and poured into a mold for manufacturing small castings such as dental and decorative articles, and in particular, shaping and reinforcement of the mold. The present invention relates to a metal ring for a mold used for a metal mold.

[0002]

2. Description of the Related Art In a precision casting apparatus, a mold used for the casting is usually manufactured by a lost wax method. In other words, a casting prototype is made of brazing material, and the surroundings are filled with high-temperature, heat-resistant gypsum. After natural drying and curing, the internal brazing material is melted and evaporated in a high-temperature firing furnace at about 800 ° C. The mold is completed with the interior of the plaster hollow. here,
When filling gypsum, the original brazing material of the casting is placed inside a metal tube.

[0003] The above-mentioned metal tube is used for the purpose of mechanical reinforcement protection at the time of handling because gypsum is mechanically brittle, and for adjusting the outer shape of a mold. This metal tube is commonly referred to in the industry as a metal ring for a mold. In the case of melting a metal in a crucible in a casting apparatus using high-frequency induction heating, a mold is placed near the crucible with the metal ring for the mold attached.

[0004]

When the metal is melted, the metal ring for the mold is induction-heated by high frequency, and the temperature of the metal ring becomes high. This shortens the life of the metal ring and shortens the life of the metal ring. Will be exposed. In addition, extra power for heating the metal ring is consumed.

In order to solve this problem, the present invention is intended to suppress the heating of the metal ring and to reduce the waste of induction heating power.

[0006]

The precision casting mold of the present invention melts a metal in a crucible disposed inside a high-frequency induction heating coil by high-frequency induction heating, and melts the melted metal by the high-frequency induction heating. Placed near the heating coil,
In a precision casting mold that is cast into a mold mechanically reinforced by a mold metal ring, the mold metal ring is a mold metal ring provided with a plurality of slit-shaped cuts.

That is, the induced eddy current generated by the high frequency induction generated in the metal ring for casting is finely divided by the plurality of slit-shaped cuts, and the electric resistance of the path through which the eddy current flows is increased. Thereby, the generation of the eddy current is suppressed, and the heating of the metal ring is suppressed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention and an embodiment thereof will be described below with reference to FIGS. 1 to 3. FIG. FIG. 2 shows a process for producing a precision casting mold. That is, 1
Is a rubber mold used to form a gate when pouring molten metal into a mold. Reference numeral 3 denotes a metal ring for a mold provided for mechanical reinforcement of the mold.
As shown in the plan view of FIG. 2 and the front view of FIG. 3B, a plurality of slit-shaped cuts 9 are provided in the axial direction. Then, as shown in FIG. 2 (a), a metal ring 3 for a mold is erected on the rubber mold 1 and a brazing material 2 and a gypsum material 4 serving as a prototype of a precision casting are placed in the metal ring 3 for a mold. Put it in and let it dry naturally to cure the gypsum.

After curing, as shown in FIG. 2 (b), the metal ring 3 for the mold is removed from the rubber mold 1 and about 800
The internal brazing material 2 is melted and evaporated in a high-temperature sintering furnace at a temperature of 0 ° C., so that the cavity of the casting mold is completed in the gypsum, and the mold 5 is completed.

FIG. 3 shows an example of a casting apparatus for melting metal by high-frequency induction heating and casting the molten metal into a mold. In FIG. 3A, reference numeral 6 denotes a crucible,
For example, it has a structure that can be divided in the vertical direction. Reference numeral 7 denotes an induction heating coil arranged on the outer mold of the crucible 6. 8
Is the metal to be melted.

Now, as shown in FIG. 3 (a), a crucible 6 is arranged inside the upper high-frequency induction heating coil 7, and a metal to be melted is set in the crucible 6. Then, when high-frequency power is supplied from a high-frequency generator (not shown) to the high-frequency induction heating coil, the metal 8 in the crucible is heated. When this metal is heated, melted and liquefied, the crucible 6 is vertically divided as shown in FIG. 3 (b), from the lower part of the crucible 6 toward the gate of the mold 5 arranged at the lower part of the crucible. The molten metal 8 falls, and the metal flows from the gate to the cavity inside the mold 5 to produce a precision cast product.

By the way, when high-frequency power is supplied to the high-frequency induction heating coil 7, the mold metal ring 3 of the mold 5 is induction-heated by the magnetic flux of the high-frequency induction heating coil 7. However, a plurality of slit-shaped cuts 9 in the axial direction provided in the metal ring for mold 3 increase the electric resistance in the circumferential direction, reduce the generation of eddy currents, and are divided. Heating is suppressed, and unnecessary consumption of induction heating power can be suppressed.

In the above embodiment, a plurality of slit-shaped cuts 9 are provided in the axial direction. However, the direction, position and number of the slit-shaped cuts 9 are limited to the axial direction due to the positional relationship between the high-frequency induction heating coil and the mold. Alternatively, any direction, position, and number can be provided.

In order to prevent a problem that a part of gypsum leaks from the cut 9 when the gypsum is filled by the slit cut 9, the slit cut 9 is wrapped with a water-resistant paper tape or the like before filling with gypsum. Just do it. After the gypsum has dried and hardened, the tape is peeled off.

[0015]

According to the precision casting mold of the present invention, the heating of the metal ring for the mold is suppressed, and the consumption of unnecessary induction heating power is suppressed. Further, the repetitive life of the metal ring for a mold can be extended.

[Brief description of the drawings]

FIG. 1 is an external view showing an embodiment of a precision casting mold according to the present invention.

FIG. 2 is a process chart for forming a precision casting mold of the present invention.

FIG. 3 is a schematic diagram of a configuration of a main part of the precision casting apparatus.

[Explanation of symbols]

 Reference Signs List 1 (rubber) mold material 2 brazing material 3 metal ring for mold 4 gypsum 5 mold 6 crucible 7 coil for high frequency induction heating 8 metal 9 slit cut

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B22C 9 / 02,9 / 04

Claims (1)

(57) [Claims] A metal in a crucible disposed inside a high-frequency induction heating coil is melted by high-frequency induction heating, and the molten metal is disposed near the high-frequency induction heating coil, and a metal ring for a mold is provided. 1. A precision casting mold, wherein the casting metal ring is a casting metal ring provided with a plurality of slit-shaped cuts, wherein the casting metal ring is a casting-molded metal ring.