Suction pressure casting method

Patent metadata

Field	Value
Publication number	US-2018133788-A1
Application number	US-201515570388-A
Country	US
Kind code	A1
Filing date	May 22, 2015
Priority date	May 22, 2015
Publication date	May 17, 2018
Grant date	—

Abstract

A suction pressure casting method uses a casting device that includes a holding furnace for accumulating molten metal, a metal mold and a core forming a cavity, a molten-metal pressurizing tank that supplies a pressurizing gas, and a suction and exhaust tank for sucking and exhausting the inside of the cavity. A preset decompression pattern of a casting process is compared with a measured pressure pattern of the cavity and the core that is measured during actual casting. A corrected decompression pattern is calculated based on a difference therebetween. The preset decompression pattern at the time of the next casting is then corrected by using the corrected decompression pattern.

First claim

1 . A suction pressure casting method comprising
using a casting device including a holding furnace in which molten metal is accumulated, a metal mold that forms a cavity together with a core, a molten-metal pressurizing means for supplying pressurizing gas into the holding furnace, and a suction-exhaust means for suctioning and exhausting an interior of the cavity, and upon carrying out suction pressure casting in which molten metal is pressurized and poured into the cavity of the metal mold and the cavity is suctioned and exhausted, setting a preset decompression pattern of the suction-exhaust means in advance according to a casting process and comparing with a measured pressure pattern of the cavity and the core that is measured during actual casting to calculate a corrected decompression pattern of the suction-exhaust means based on a difference therebetween, and correcting the preset decompression pattern at a time of the next casting by using the corrected decompression pattern.

2 . The suction pressure casting method according to claim 1 , wherein
the measured pressure pattern of the cavity and the core comprises a first time period from a start of pouring of the molten metal to a completion of pouring, a second time period from the completion of pouring the molten metal to when a solidified film of the molten metal is formed in a periphery of the core, and a third time period from the formation of the solidified film of the molten metal in the periphery of the core to when the suctioning and exhausting of the cavity is stopped, and the corrected decompression pattern of the suction-exhaust means is calculated based on the difference between the preset decompression pattern and the measured pressure pattern, and at which time period the measured pressure deviates from the preset decompression pattern is displayed by a display means.

3 . The suction pressure casting method according to claim 2 , further comprising
using a preset pressurizing pattern of the molten-metal pressurizing means set in advance according to the casting process, in the second time period from the completion of pouring of the molten metal to when the solidified film of the molten metal is formed in the periphery of the core, and determining that an abnormality has occurred in a cast product when the measured pressure of the core exceeds the molten metal pressure of the periphery of the core determined from the preset pressurizing pattern of the molten-metal pressurizing means.

4 . The suction pressure casting method according to claim 2 , wherein
using a preset pressurizing pattern of the molten-metal pressurizing means set in advance according to the casting process, in the second time period from the completion of pouring of the molten metal to when the solidified film of the molten metal is formed in the periphery of the core, and a corrected decompression pattern is calculated such that the difference between the measured pressure of the core and the molten metal pressure of the periphery of the core determined from the preset pressurizing pattern of the molten-metal pressurizing means becomes a predetermined value or less.

5 . The suction pressure casting method according to claim 1 , wherein
the suction-exhaust means comprises a vacuum tank and an exhaust valve that opens and closes a suction and exhaust path from the vacuum tank to the cavity, and the preset decompression pattern and the corrected decompression pattern are patterns for controlling the opening amount of the exhaust valves.

6 . The suction pressure casting method according to claim 2 , wherein
the suction-exhaust means comprises a vacuum tank and an exhaust valve that opens and closes a suction and exhaust path from the vacuum tank to the cavity, and the preset decompression pattern and the corrected decompression pattern are patterns for controlling the opening amount of the exhaust valves.

7 . The suction pressure casting method according to claim 3 , wherein
the suction-exhaust means comprises a vacuum tank and an exhaust valve that opens and closes a suction and exhaust path from the vacuum tank to the cavity, and the preset decompression pattern and the corrected decompression pattern are patterns for controlling the opening amount of the exhaust valves.

8 . The suction pressure casting method according to claim 4 , wherein
the suction-exhaust means comprises a vacuum tank and an exhaust valve that opens and closes a suction and exhaust path from the vacuum tank to the cavity, and the preset decompression pattern and the corrected decompression pattern are patterns for controlling the opening amount of the exhaust valves.

Assignees

• Nissan Motor

Inventors

• Shiga Hidetoshi
• Tsuchiya Shinnichi
• Masuta Tatsuya
• Hayashi Kenji

Classifications

• B22D18/06 Primary

  Vacuum casting, i.e. making use of vacuum to fill the mould · CPC title

• B22D17/22

  Dies (manufacture, see the appropriate class, e.g. B23P15/24); Die plates; Die supports; Cooling equipment for dies; Accessories for loosening and ejecting castings from dies · CPC title

• B22D18/04

  Low pressure casting, i.e. making use of pressures up to a few bars to fill the mould · CPC title

• B22C9/00

  Moulds or cores (uniquely adapted to particular casting processes B22D); Moulding processes · CPC title

• B22D18/08

  Controlling, supervising, e.g. for safety reasons (controlling or regulating in general G05) · CPC title