Claims
- 1. A method for vacuum casting, comprising:
- providing a gas-tight chamber having an insertion hole for inserting a straight tubular stalk and evacuated when performing vacuum casting;
- providing a die accommodated in the gas-tight chamber and having an inlet to a cavity within the die;
- inserting the stalk through the insertion hole of the gas-tight chamber for leading molten metal into the die;
- providing a flange mounted on a periphery of an insertion side end of the stalk;
- forming a recess bounded by a surface of the die, a surface of the stalk, and a surface of the flange;
- providing a first degree of vacuum in the gas-tight chamber to withdraw the molten metal into the stalk to a level above a die side end of the stalk and below the inlet of the cavity of the die, until the molten metal overflowing from the die side end of the stalk is introduced into the recess;
- allowing the molten metal in the recess to cool and solidify to form a seal between the stalk and the flange; and
- after the molten metal in the recess has cooled and solidified to form a seal between the stalk and the flange, providing a second degree of vacuum in the gas-tight chamber to withdraw the molten metal into the die cavity.
- 2. The vacuum casting method as defined in claim 1, further comprising coating the contact surfaces of the stalk and the flange with a seal material.
- 3. The vacuum casting apparatus as defined in claim 1, further comprising coating an underside of the flange with a seal material.
- 4. A vacuum casting apparatus comprising:
- a gas-tight chamber having an insertion hole for inserting a straight tubular stalk and evacuated when performing vacuum casting;
- a die accommodated in said gas-tight chamber and having an inlet to a cavity within the die;
- said stalk inserted through the insertion hole of said gas-tight chamber for leading molten metal into said die;
- a flange mounted on a periphery of an insertion side end of said stalk;
- a recess formed by a surface of the die, a surface of the stalk, and a surface of the flange; and
- preliminary evacuation means for provisionally providing a first degree of vacuum in said gas-tight chamber to withdraw the molten metal into said stalk to a level above a die side end of said stalk and below the inlet of a cavity of said die, until the molten metal overflowing from the die side end of said stalk is introduced into the recess and the molten metal in the recess cools and solidifies to form a seal between the stalk and the flange, before providing a second degree of vacuum in said gas-tight chamber to withdraw the molten metal into the cavity of said die.
- 5. The vacuum casting apparatus as defined in claim 4, wherein the contact surfaces of the stalk and the flange are coated with a seal material.
- 6. The vacuum casting apparatus as defined in claim 5, wherein the seal material is coated on an underside of the flange.
Priority Claims (1)
Number |
Date |
Country |
Kind |
5-254408 |
Oct 1993 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 08/307,424 filed Sep. 19, 1994, now U.S. Pat. No. 5,555,925.
Foreign Referenced Citations (4)
Number |
Date |
Country |
3925373 |
Feb 1990 |
DEX |
63-84757 |
Apr 1988 |
JPX |
4-294854 |
Oct 1992 |
JPX |
4-284962 |
Oct 1992 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Soviet Patent Abstracts, SU-A-1637 949, PQ section, week 9209, Apr. 15, 1992, Derwent Publications. |
Continuations (1)
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Number |
Date |
Country |
Parent |
307424 |
Sep 1990 |
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