JPH02280945A - Casting method using core assembly - Google Patents

Abstract

PURPOSE:To obtain a casting product with molding workability and dimensional accuracy improved by setting integral assembly of plural cores partially stuck at some interval with small pieces of holding bodies lost with molten metal in a master mold. CONSTITUTION:Into positioning recessed parts 5a formed on mold surface in a drag (master mold) 5, a part and base part of core part in the core 2 and tip part of the core part in the core 3 constituting the core assembly 1 are fitted to set the assembly q in the drag 5. Successively, the cope (master mold) 6 is clamped to the drag 5. Successively, the prescribed molten metal is poured into cavity 7 formed with the assembly 1, drag 5 and cope 6 from a sprue. Then, by this molten metal, the above holding bodies 4 and adhesive bonding these and cores 2, 3 are lost and the casting product just corresponding to shape of the cavity 7 is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a casting method using a core assembly formed by integrating a plurality of cores.

(Prior art) A plurality of cores are placed in a main mold at intervals,
In conventional casting methods for casting parts with complex shapes, multiple cores are placed individually in the corresponding thick part of the main mold, or multiple cores are placed in a mold. If they were in contact at a certain part, that contact part was bonded with adhesive or glue, and the bonded core was placed inside the main mold.

(Problem to be Solved by the Invention) However, with the former method of holding the core between the cores, it is necessary to individually assemble the core into the main mold, so the centering of the core, etc. The disadvantages are that the work is troublesome and the number of man-hours required is large. On the other hand, the latter method of adhesively fixing a plurality of cores together has a problem in that it is difficult to apply when the cores do not come into contact with each other due to the shape of the cores.

(Means for Solving the Problems) The present invention is intended to solve the above problems, and its purpose is to provide a casting method using a core assembly that improves molding workability and dimensional accuracy. do.

A casting method using the core assembly of the present invention to achieve such an objective is to reduce the gap between a plurality of cores stacked in one direction at intervals in a main mold. The plurality of cores are integrated by partially interposing a small piece-shaped holder made of a material that disappears with the molten metal during casting, and bonding the holder and the surrounding core. It is characterized in that the core assembly is installed, the main mold is then clamped, and then molten metal is poured into the main mold.

In the method of the present invention, the cores laminated and assembled along one direction can be installed in the main mold as they are.

The size of the holder should be as small as possible to properly hold the core, and the shape should be such that it is easy to handle. In other words, the holder is shaped like a small plate or column.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a structure in which the core assembly used in the method of the present invention is held integrally with a gap. That is, each holder 4 is bonded with adhesive to the upper surface of the core of the core 2, which corresponds to the main body core, and the core 3, which corresponds to the small core, is positioned in the center by a core setter (centering device N). While the positioning part 3a of the base of the core 3 is fitted into the positioning recess 2a of the base of the core 2, the core of the core 3 is adhered with the adhesive applied to the upper surface of the holder 4, and the core of the core 3 is attached to the base of the core 2. are integrally connected to.

The holder 4 is made of a material that easily vaporizes and disappears with the molten metal during casting, and is designed to reduce the amount of gas generated and to reduce the amount of gas generated during vaporization so as not to adversely affect the quality of the cast product. It has a structure with as low density as possible to reduce the amount of heat absorbed. The fugitive material should be selected depending on the core shape and the type of material to be poured.
For example, paper or foamed polystyrene, and in some cases, foamed polyethylene or foamed polyurethane can also be used.

The adhesive used to bond the core 2.3 and the holder 4 may be one that is easily vaporized and lost by molten metal, such as a synthetic rubber or ethylene-vinyl acetate resin adhesive, similar to the holder 4. use. In particular, the core 2.3 and the holder 4
It is preferable to use an adhesive that firmly adheres the two. Furthermore, in order to prevent the adhesive from vaporizing and adversely affecting the quality of the cast product, the amount of adhesive used should be one that generates a small amount of gas and has a low amount of heat absorption during vaporization. The amount should be such that

In order to mold and cast using such a core assembly l, first, as shown in FIG. Core 2 that makes up body l
Insert a part of the core and the base of the core and the tip of the core of the core 3.

The core assembly l is installed in the lower mold 5. Then, as shown in FIG. 3, the upper mold (main mold) 6 is clamped to the lower mold 5, thereby completing the molding work.

Then, a predetermined amount of molten metal is poured into the cavity 7 formed by the core assembly 1, the lower mold 5, and the upper mold 6 from a sprue (not shown). The molten metal easily eliminates the holder 4 and the adhesive bonding it to the core 2.3.
A product that matches the shape of the cavity 7 can be obtained.

FIG. 4 shows another embodiment of the core assembly used in the method of the present invention. This core assembly 1° is made by positioning the core 3° corresponding to the small core with a core setter. , middle child 3
The base of the core 2° corresponds to the main body core, and the recess 2 at the base of the core 2°
At the same time, insert the core tip of the core 3° into the core 2
The core 2° and the core 3° are integrated by bonding the core 4° to the holder 4° that is glued to the tip of the core. A 4° holder is attached to each of the 2° core tip and the 3° core tip. In such a core assembly l'.

Holders 4'' provided at the tips of the cores of cores 2° and 3° are in contact with or adhered to the mold surface of the lower mold 5° and the upper mold 6°, respectively, and the core assembly 1 is assembled. ° will be firmly installed in the lower mold 5° and the upper mold 6°.

In the above-mentioned embodiment, the core is installed in the main mold without using a thick core, but the core may be used depending on the case. Although the case where two cores are used is taken as an example, the number of cores is not limited to this, and a plurality of cores may be integrated depending on the product.

(Effects of the Invention) As described above, the method of the present invention uses a small piece-shaped holder made of a material that disappears with the molten metal during casting and partially interposed in the gap between the cores, regardless of the shape of the cores. A core assembly made by adhesively bonding a plurality of cores stacked in one direction can be easily molded by placing it in the main mold as it is. After tightening, molten metal is injected into the main mold and cast, so molding work efficiency is dramatically improved compared to the conventional case where multiple cores were individually held between the cores and placed inside the main mold. Furthermore, it is possible to obtain a cast product with good dimensional accuracy by eliminating the possibility of misalignment occurring during core installation work.

Further, in the method of the present invention, since the holder used for assembling the core is in the form of a small piece, it does not generate a large amount of gas when it decomposes and disappears, and this does not cause quality defects in the cast product.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of a core assembly used in the method of the present invention. FIG. 2 is a sectional view showing the core assembly shown in FIG. 1 installed in a lower mold. Figure 3 is a sectional view showing the state in which the upper mold is clamped to the lower mold in Figure 2, and Figure 4 shows a core assembly different from that in Figure 1 between the lower mold and the upper mold. FIG. 3 is a sectional view showing the assembled state. l... Core assembly body 4... Holding body 2.3... Core

Claims (1)

[Claims] Inside the main mold, a small piece-shaped holder made of a material that disappears with the molten metal during casting is partially installed in the gap between a plurality of cores stacked in one direction at intervals. A core assembly formed by integrating the plurality of cores is installed by interposing and bonding the holding body and the core around it, and then, after clamping the main mold, the main mold A casting method using a core assembly characterized by injecting molten metal into the core assembly.