JPH05220541A - Precision casting method - Google Patents

Abstract

PURPOSE:To prevent the generation of defective protrusion on the surface of a product by releasing to the atmosphere after sticking slurry on a formed product composition body and making air bubbles contained in the slurry bulged, bursted and eliminated. CONSTITUTION:The formed body 5 having the same shape as the product is formed and the coating is applied by the slurry and refractory particles on this formed body 5, and successively the formed body 5 is replaced into a metal to cast the product. At the time of applying the coating on this formed body 5, the slurry is stuck on this formed body 5 in the pressurizing condition. By releasing the slurry stuck to the formed body 5 in the pressurizing condition, the bubbles of the air contained in the slurry are expanded and bursted. In this result, the air having bubble-state in the slurry stuck to the formed body 5 is smoothly discharged (defoamed) to the outer part. By this method, the generation of the defective protrusion on the surface of the precision cast product can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precision casting method in which a molded product having the same shape as a product is molded, the molded product is coated, and then the molded product is replaced with a metal to cast the product.

[0002]

2. Description of the Related Art Generally, in a precision casting method, a molded product having the same shape as a product is molded, the molded product and a runner molding portion are connected to each other, and a tree-shaped molded product assembly is assembled. Slurry and refractory particles are alternately deposited on this molded product assembly to form a coating layer.When a slurry is deposited on a molded product with a complicated shape, air bubbles are trapped in the slurry. However, there is a problem in that the bubbles are easy to come out and are hard to come out to the outside. When the coating layer is formed in the state where the foamy air mixed in the slurry adhering to the molded product is not discharged (defoamed) to the outside during the coating, the coating layer is dried. Then, when baking is performed to form a mold and a product is cast in the mold, there is a problem that bubble-like protrusions (defects) are generated on the surface of the product.

[0003]

The problem to be solved by the present invention is that during the coating, the foamy air in the slurry adhering to the molded product is not smoothly discharged (defoamed) to the outside. This is a problem that protrusion defects occur on the surface of the cast product.

The present invention has been made in view of the above circumstances, and an object thereof is to smoothly discharge the bubble-like air in the slurry adhering to the molded article to the outside (defoaming) during coating. The present invention provides a precision casting method capable of preventing the occurrence of protrusion-like defects on the surface of a precision-cast product.

[0005]

In order to achieve the above object, the present invention is to form a molded article having the same shape as the product, and to coat the molded article with slurry and refractory particles,
Then, in the precision casting method in which the molded product is replaced with a metal to cast the product, the slurry is adhered to the molded product under pressure when coating the molded product.

[0006]

In the precision casting method of the present invention, by adhering the slurry to the molded article under pressure and then opening it to atmospheric pressure, the air bubbles contained in the slurry expand and pop. Defoaming is performed smoothly.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

In FIGS. 1 and 2, reference numeral 1 is a pressurizing box having an openable / closable lid 2, and the pressurizing box 1 contains an aqueous slurry 3. A pressure pipe 4 for pressurizing the inside is connected to the pressure box 1. Further, in the pressure box 1, a rotary jig 6 mounted at the center of a tree-shaped molded product assembly 5 is horizontally arranged. The rotary jig 6 is detachably provided with a rotating mechanism for rotating the rotary jig 6 and an elevating mechanism for moving the rotary jig 6 up and down. Further, the molded product assembly 5 includes a wax runner molding part 5a mounted around the rotary jig 6 and a wax having the same shape as the product, which is connected around the runner molding part 5a. It is composed of a molded product 5b.

In the slurry depositing apparatus constructed as described above, first, the runner molding portion 5a and the wax molding 5b, which are molded by the injection molding method in advance, are connected to each other,
After the tree-shaped molded product assembly 5 is assembled, the molded product assembly 5 is horizontally arranged in the pressure box 1 with the rotary jig 6 attached to the center of the molded product assembly 5, and the pressure pipe 4 is attached. Through,
The inside of the pressure box 1 is pressurized. Next, while lowering the molded product assembly 5 by the elevating mechanism to immerse the molded product assembly 5 in the slurry 3 and rotating the molded product assembly 5 about the rotary jig 6 by the rotating mechanism, as shown in FIG. As shown, the first layer slurry 3 is attached to the surface of the molded product assembly 5. Subsequently, the molded product assembly 5 is lifted together with the rotary jig 6 by the elevating mechanism and lifted above the liquid surface of the slurry 3 to release the pressured state in the pressure box 1. Return to atmospheric pressure. As a result, the air bubbles mixed in the slurry 3 adhering to the surface of the molded product assembly 5 expand and pop to smoothly degas.
Then, the slurry 3 flows from around to the location where the air bubbles have burst, so that the surface of the molded product assembly 5 is in a state in which a healthy slurry 3 containing no air bubbles is attached. In this state, the lid 2 of the pressure box 1 is opened, the molded product assembly 5 is carried out, and refractory particles are sprayed on the surface of the molded product assembly 5 to form the first coating layer. Then, the above operation is repeated a plurality of times to complete the coating process.

Further, in FIG. 3, reference numeral 10 is a pressurizing chamber which has a door 11 which can be opened and closed and which can be freely run. Inside the pressurizing chamber 10, a rotatable slurry tank 12 is provided with a rotating shaft 13.
It is arranged in a state of being connected to. A seal 14 for sealing is attached around the rotary shaft 13. Further, a pressurizing means such as a blower is connected to the pressurizing chamber 10 via an electromagnetic valve 15. Further, an air cylinder 16 is provided above the pressurizing chamber 10.
Is provided upright. The tip of the piston rod of the air cylinder 16 is adapted to detachably support the attachment 18 that is suspended in the pressurizing chamber 10 and projects from the upper portion of the molded product assembly 17. ing. In the slurry adhering apparatus configured as described above, the inside of the slurry 3 accommodated in the rotating slurry tank 12 is pressurized in the pressure chamber 10 by the pressure means via the electromagnetic valve 15. Then, the piston rod of the air cylinder 16 is lowered to immerse the molded article assembly 17 so that the slurry 3 is attached to the surface of the molded article assembly 17, and then the molded article assembly 17 is slurried by the air cylinder 16. Lift above the liquid level of. In this state, when the pressure inside the pressure chamber 10 is released and returned to atmospheric pressure, the air bubbles mixed in the slurry 3 adhering to the surface of the molded product assembly 17 expand and pop off. , Defoaming is performed smoothly. Then, the slurry 3 flows into the area where the air bubbles have burst, and the sound slurry 3 containing no air bubbles is attached to the surface of the molded product assembly 17. Then, the door 11 of the pressurizing chamber 10 is opened, the molded product assembly 17 is carried out, and refractory particles are sprayed on the surface of the molded product assembly 17 to form the first coating layer.

[0011]

As described above, according to the present invention, a molded product having the same shape as that of the product is molded, the molded product is coated with slurry and refractory particles, and then the molded product is replaced with a metal product. In the precision casting method for casting, when applying the coating to the molded product, the slurry is attached to the molded product under pressure,
By releasing the slurry adhering to the molded product under pressure to atmospheric pressure, the air bubbles contained in the slurry expand and pop out, thereby removing the foamy air in the slurry adhering to the molded product. It can be smoothly discharged (defoamed) to the outside, and it is possible to prevent the generation of protrusion defects on the surface of the precision-cast product.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing the movement of the molded product assembly.

FIG. 3 is a schematic front view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Pressure Box 5/17 Molded Product Assembly 5a Runner Molding Part 5b Wax Molded Product 10 Pressure Chamber

Claims (1)

[Claims] 1. A molded product having the same shape as the product is molded, and the molded product is coated with slurry and refractory particles,
Then, in the precision casting method of casting a product by replacing the above-mentioned molded product with a metal, a slurry is adhered to the above-mentioned molded product under pressure when coating the above-mentioned molded product.