JPH06254657A - Treatment of forming surface in mold for shell molding - Google Patents

Abstract

PURPOSE:To provide a treating method by which the forming surface of a mold for shell molding can smoothly be formed with high quality and good workability without contaminating the working environment. CONSTITUTION:In this method for treating the forming surface of the mold for shell molding, a core 4 is arranged in a closed space 11 in which fine pulverized coating agent 3 is floated, and by executing sucking from the opposite side to the forming surface 41 of the core 4, the fine pulverized coating agent 3 is sucked from the forming surface 41 and filled in the gap among the grains consisting the core 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding surface treatment method for shell molds. Here, the shell mold is the shell and core used in the shell molding operation, and the molding surface is the inner surface of the shell and the outer surface of the core.

[0002]

2. Description of the Related Art Shells and cores used in shell molding operations are generally composed of sand mixed with carboxylic acid-based synthetic resin powder (that is, resin sand), so that the surface is relatively rough. ing. Therefore, the casting produced by using the shell and core has a drawback that the surface, that is, the casting surface, is relatively rough.

Therefore, conventionally, in order to make the molding surfaces of the shell and the core smooth, a liquid agent in which graphite, an adhesive and the like are dispersed in water is coated on the molding surfaces by dipping or the like.

However, the method using the above-mentioned liquid agent is troublesome because it requires the work of evaporating the water content, is liable to pollute the working environment, and is inferior in performance and cost.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a processing method capable of smoothing the molding surface of a shell mold with good workability and without contaminating the work environment with high quality. .

[0006]

[Means for Achieving the Object] A method for treating a molding surface of a mold for shell mold of the present invention is to install a mold for shell mold in a closed space in which a fine powder coating agent is suspended, It is characterized in that suction is performed from the side opposite to the molding surface so that the fine powder coating agent is sucked and packed from the molding surface side into the gaps between the particles constituting the shell mold.

As the fine powder coating agent, an inorganic compound which is solid and is used as a lubricant and has a heat insulating property is used. Specifically, one or more of boron nitride, mica, metal oxide, silicon nitride, sulfur compound, fluoride, talc, boron compound, phosphorus compound and graphite are used.

The fine powder coating agent is from 0.5 to
The size of 1.5 μm is preferable.

[0009]

Since the fine powder coating agent is filled in the gaps between the particles forming the shell mold from the molding surface side, the molding surface becomes very smooth. Since the coating agent is fine powder, gaps remain between the fine powders, and the gas generated during casting escapes through the gap.

Since only the shell mold is installed in the closed space in which the fine powder coating agent is suspended and suction is performed, the work is simple and can be automated.

The work environment is not polluted because the fine powder coating agent is simply packed in the closed space.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional side view showing a working state for carrying out the method of the present invention. In the figure, 1 is a powder floating device, 2
Is a suction device and the method of the invention is carried out with both devices 1, 2.

The powder floating device 1 comprises a fine powder coating agent 3
Is provided with a closed space 11 in which the suction pipe 21 of the suction device 2 communicates with the closed space 11 through an opening 12. Inside the closed space 11, a core 4 which is a mold for shell molding is installed so as to close the opening 12 and expose the molding surface 41 to the closed space 11. That is, the closed space 11 is closed by installing the core 4. The core 4 is made of resin sand, and has a cavity 42 that opens into the suction tube 21 at the center. The particle size of the resin sand is 0.1 to 0.2 mm. The fine powder coating agent 3 has a particle size of 0.5 to 1.5.
It is a water-containing amorphous silicon dioxide having a size of μm.

The method of the present invention is carried out as follows. That is, in the state of FIG. 1, the suction device 2 is operated to perform suction. According to this, FIG. 2 which is an enlarged view of part A of FIG.
As shown in FIG.
And, it is attracted to the core 4 through the cavity 42 and sucked into the gap 44 between the particles 43 forming the core 4 to be clogged.

According to the above method, the fine powder coating agent 3 is packed so as to fill the concave portion of the molding surface 41 of the core 4, so that the molding surface 41 becomes very smooth.

Further, since the core 4 is simply installed in the closed space 11 in which the fine powder coating agent 3 is suspended and suction is performed, the work is simple and the automation is possible.

Further, since the fine powder coating agent 3 is only packed in the closed space 11, the working environment is not polluted.

In the core 4 treated by the above method, even if the fine powder coating agent 3 is filled in the gap 44, there is a gap between the fine powder coating agents 3, so that the gas generated during casting is It will come out through the gap. Therefore, there is no hindrance to the casting work using the core 4.

[0019]

[Other Embodiments] The method of the present invention can be applied to a shell 5 instead of the core 4 as the target shell mold. FIG. 3 is a partial cross-sectional side view showing a working state in which the method of the present invention is performed on the shell 5. Shell 5 too
It is installed in the closed space 11 so as to close the opening 12 and expose the molding surface 51 to the closed space 11. The shell 5 is installed via the member 6 in order to expose the molding surface 51 to the inside of the closed space 11. Other configurations are the same as those in the above-mentioned embodiment. Also in this embodiment, the same operations and effects as those in the above embodiment are performed.

[0020]

As described above, according to the molding surface treatment method for the shell mold of the present invention, the shell mold (for example, the core) is placed in the closed space 11 in which the fine powder coating agent 3 is suspended. 4) is installed and molding surface 4 of core 4
Since the fine powder coating agent 3 is sucked into the gap 44 between the particles 43 forming the core 4 from the side of the molding surface 41 by suction from the side opposite to 1, the following effects can be obtained. .

(1) The fine powder coating agent 3 is the core 4
Since the molding surface 41 is clogged so as to fill the recess, the molding surface 41 can be made extremely smooth.

(2) Since only the core 4 is installed in the closed space 11 in which the fine powder coating agent 3 is suspended and suction is performed, the work can be simplified and automation can be realized.

(3) Since the fine powder coating agent 3 is simply filled in the closed space 11, the work environment can be prevented from being contaminated.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing a working state of an embodiment according to the method of the present invention.

FIG. 2 is an enlarged view of part A in FIG.

FIG. 3 is a partial cross-sectional side view showing a working state of another embodiment according to the method of the present invention.

[Explanation of symbols]

 3 Fine powder coating agent 4 Core 5 Shell 11 Closed space 41, 51 Molding surface 43 Particle 44 Gap

Claims (3)

[Claims] 1. A method for treating a molding surface of a shell mold, which is performed for smoothing an inner surface of a shell or an outer surface of a core used for shell molding work, in a closed space in which a fine powder coating agent is suspended. , The shell mold is installed, suction is performed from the side opposite to the molding surface of the shell mold, and the fine powder coating agent is sucked into the gap between the particles forming the shell mold from the molding surface side. A molding surface treatment method for a shell mold, which is characterized in that it is filled with. 2. The fine powder coating agent is an inorganic compound which is solid and used as a lubricant and has a heat insulating property. Examples of the inorganic compound include boron nitride, mica, metal oxides, silicon nitride, sulfur compounds and fluorine compounds. The method for treating a molding surface of a mold for shell mold according to claim 1, wherein at least one of a compound, a talc, a boron compound, a phosphorus compound and graphite is used. 3. The fine powder coating agent comprises 0.5 to 1.
The molding surface treatment method for a shell mold according to claim 1, wherein the molding surface has a size of 5 μm.