JPH04270026A - Molding flask - Google Patents

Abstract

PURPOSE:To quickly discharge gas produced with combustion of a consumable pattern from a mold to an external part. CONSTITUTION:A chamber 5 is set at the bottom part of a box type molding flask main body 1 opened at an upper part. Gas venting bodies 6 embedded in a dry sand 2 are erected in a chamber 5 and also gas discharging tube communicated with the outer part is connected. The gas produced with the combustion of consumable pattern 3 is discharged to the outer part from the upper opening part in the molding flask body 1 and also discharged to the external part from the gas discharging tube 7 through the gas venting bodies 6 and the chamber 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a casting flask used in an investment casting method.

0002

[Prior Art] A casting flask used in the disappearing model casting method has a box-shaped flask body with a number of ventilation holes on the bottom and a wire mesh, and a box body forming a decompression chamber around the outer periphery of the flask. It is set up. The flask body is filled with dry sand that does not contain a binder, and a mold is made by embedding a disappearing model made of foamed resin in the dry sand (for example,
2-5004, Figure 2).

0003

[Problem to be Solved by the Invention] Conventional molds generate a large amount of gas when the disappearing model disappears with the molten metal, so the gas is discharged to the outside through the vent hole in the flask body and through a decompression chamber. However, since the mold uses dry sand that does not contain a binder, the light sand may be engulfed by the gas during degassing and come out of the mold body through the ventilation hole, or when dry sand is added or due to vibrations. During molding, it spills out of the ventilation holes and accumulates in the vacuum chamber. Therefore, there is a problem that degassing from the decompression chamber becomes worse. Therefore, the present invention has been made to solve this problem, and provides a flask with good degassing.

0004

[Means for Solving the Problems] The flask of the present invention has a chamber disposed at the bottom of the flask body, and a gas vent buried in dry sand is installed in the chamber and communicates with the outside. It is connected to an exhaust pipe.

[0005]

[Function] During pouring, the gas generated inside the flask due to the combustion of the disappearing model moves through the dry sand, passes through the venting gas, vents into the chamber, then rises in the exhaust pipe and exits from the upper opening. It is discharged to the outside.

[0006]

[Embodiment] Fig. 1 shows an embodiment of the flask according to the present invention, in which a box-shaped flask body 1 with an open top is filled with dry sand 2 containing no binder. A disappearing model 3 made of foamed resin is buried in the area. A rectangular underframe 4 is provided at the bottom of the flask body 1, and a chamber 5 is provided at the bottom of the flask body 1, and the chamber 5 is attached to the bottom surface of the flask body 1 by a bolt (not shown). Fixed. A gas vent 6 buried in the dry sand 2 is erected on the upper surface of the chamber 5, and an exhaust pipe 7 communicating with the outside is connected thereto, and an appropriate number of the gas vents 6 and exhaust pipes 7 are each provided. The gas vent 6 is formed from a bottomed cylindrical body 6b having a circular tube 6a, and a slit width of 0.1 to 0.2 is formed on the top surface of the cylindrical body 6b.
mm slit vent (not shown) is provided, the surface of the cylindrical body 6b is formed from a cylindrical mesh of 200 to 400 mesh, while the exhaust pipe 7 is formed from a flexible pipe, and the flask body 1
, a gas vent 6, a chamber 5, and an exhaust pipe 7 are provided so as to be freely communicable with each other. Slit width 0.1-0.2mm
The slit vent (not shown) and the cylindrical mesh of 200 to 400 mesh do not cause sand spillage and have a good gas venting effect.

[0007] Next, an extinguishable model casting method using the flask will be explained. Disappearance model 3 is created by pouring molten metal into the interior of vanishing model 3.
The casting 8 is cast by replacing the molten metal with the molten metal. During this pouring, the gas generated by the combustion of the vanishing model 3 is the dry sand 2
It moves inside and is discharged to the outside from the upper opening of the flask body 1, and is also vented to the chamber 5 through the venting gas 6, and then ascends inside the exhaust pipe 7 and is discharged to the outside from the upper opening. . In this flask, dry sand 2 is removed from the flask body 1 when the gas is vented.
There is no leakage of dry sand 2 from the flask main body 1 to the gas evacuator 6 during sand injection or molding.

[0008]

[Effects of the Invention] According to the present invention, a chamber is provided at the bottom of the flask body, a gas vent buried in dry sand is provided upright in the chamber, and an exhaust pipe communicating with the outside is connected to the chamber. Therefore, the gas is removed quickly and there is no sand leakage, so there are no gas defects and high-precision castings can be easily obtained, which greatly contributes to improved productivity.

[Brief explanation of the drawing]

[Fig. 1] Cross-sectional view of a mold using a flask according to the present invention

[Explanation of symbols]

1 Casting flask body 2 Dry sand 5 Chamber 6. Gas removal 7 Exhaust pipe

Claims (1)

[Claims] Claim 1: In a flask with an open top used in the vanishing model casting method, a chamber is disposed at the bottom of the flask body, and a gas vent buried in dry sand is provided upright in the chamber, and A casting flask characterized by having an exhaust pipe connected to the outside.