JPH0318452A - Method for joining molds - Google Patents

Abstract

PURPOSE:To prevent the development of casting flash and also to prevent the development of deteriorated shape and size by pushing a cope through a pushing plate arranging a through hole having the similar shape as outline shape on parting face in a mold cavity formed with a drag and the cope. CONSTITUTION:The drag 2 molded at the other place is laid on a truck 7 directing the parting face 2a upward and on the above, the cope 1 molded with the same way is jointed directing the parting face 1a downward. Both of the parting faces 1a, 2a of the cope 1 and the drag 2 are made to projecting faces having height at center part a little higher than the height at the outer edge. The pushing plate 5 arranging the through hole 5a having the similar shape with the cavity 3 is mounted on the cope 1, and this is pushed with a pushing device 6. By this method, gap between the parting faces in the molds is eliminated by pressurized contact and the development of the casting flash is prevented, and as the cavity is not pressed, the casting having excellent accuracy in shape and size is obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method of matching molds for casting. [Prior art] Conventionally, casting molds are manufactured by attaching a model surface plate with a model on the table of a molding machine, placing a casting flask on the model surface plate, and filling molding sand into the flask. After charging the molding machine, the molding sand is compressed using the squeeze head of the molding machine and the mold is clamped.After that, the mold is removed and the upper mold and lower mold are formed, and then the parting surface is Manufactured by matching the upper mold with the cut-off side facing down over the lower mold, which is placed facing upward. However, deformation occurs mainly in the model surface plate due to insufficient rigidity of equipment such as the model surface plate and casting flask, and the flatness of the parting surfaces of the upper and lower molds after molding is not good, and it is usually This is the convex surface of . When the upper mold and the lower mold, each having a convex parting surface, are matched, a gap t is created on the mold matching surface (parting face) on the outer periphery of the cavity 3, as shown in Fig. 3, and when the molten metal is poured. There is a problem in that the molten metal flows out from this gap t and flash is generated. A similar problem also occurs when the parting surface is concave. For this reason, in the past, as shown in FIG. 4, after the mold alignment, for example, a weight 4 of considerable weight was placed on the upper mold 1, or a presser plate at the lower end of the rod of a hydraulic cylinder (not shown) was used to hold the upper mold 1. Pressure is applied from above to bring the mold mating surfaces into close contact and prevent the formation of flash. In addition, as a technology to prevent casting flash, Japanese Patent Application Laid-Open No. 62-142
There is one disclosed in Publication No. 052. This creates a band-shaped protrusion with a predetermined height and width along the outer periphery of the mold cavity, and presses the upper and lower molds together after the molds are aligned to eliminate gaps between the mold mating surfaces and prevent the formation of flash. This is what we are trying to do. [Problem to be solved by the invention] However, in any of the above cases, the upper mold and the lower mold are pressed together by pressing from above the upper mold after mold matching, and the gap between the mold mating surfaces is eliminated and the flash is removed. Although it is possible to prevent this from occurring, the problem is that the cavity 3 is deformed by the pressing force as shown in FIG. 4, resulting in, for example, a shape defect due to a bulge 3a on the vertical surface or a dimensional defect due to a reduction in the vertical dimension l. It has the following. SUMMARY OF THE INVENTION An object of the present invention is to provide a mold matching method that can solve the above-mentioned problems and prevent the occurrence of flash, as well as shape defects and dimensional defects. [Means for Solving the Problems] The present invention has been made as a result of various studies in view of the above-mentioned problems. In the mold matching method in which the upper mold is pressed from above after the upper mold is placed, a through hole is provided with a shape similar to the contour shape on the parting surface of the mold cavity formed by the lower mold and the upper mold. The method is characterized in that the upper die is pressed through a press plate that is attached to the press plate. [Operation] Since the upper mold is pressed through a pressing plate that has a through hole that approximates the contour shape on the parting surface of the mold cavity, the gap between the mold mating surfaces of the mold is the area outside the through hole of the pressing plate. This prevents the formation of flash as it is not pressed by the mold. Additionally, since the mold cavity has through-holes, no pressing force is applied directly to it, which reduces deformation and prevents defects in the shape and dimensions of the casting. [Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. Figure 1 is a front view of the main parts in cross section, Figure 2 is A of Figure 1.
-A sectional view. The lower mold 2, which has been molded by a molding machine (not shown) at another location, is placed on a mold trolley 7 on which the mold is placed and transferred, with the parting surface 2a facing upward. An upper mold 1, which was molded at a different location, is placed with the parting surface 1a facing downward, and the molds are matched. Therefore, the parting surfaces 1a of the upper mold 1 and the lower mold 2 after molding,
2a, although not shown, the center part is 1 point wider than the outer edge.
It has a convex surface with a high middle and high height. Therefore, in the above-mentioned state where the molds are matched, a gap t is created between the mold matching surfaces as shown in FIG. On casting flash occurred. However, according to the present invention, a press plate 5 provided with a through hole 5 & having a shape similar to the contour shape of the cavity 3 is placed on top of the upper mold 1 of the mold which has been molded and matched in the same manner as above. For example, by pressing with a pressing device 6 such as a hydraulic cylinder, as shown in FIG. When the parting surfaces 1a and 2b were brought into close contact with each other and the metal was poured, only 0.5 of a flash was generated on the mold mating surfaces.
n, which was a significant reduction compared to the conventional method. In addition, there were no defects in the resulting castings, such as poor shape due to bulging of the mold or poor dimensions due to crushing of the gun-shaped cavity, both of which were within acceptable limits. [Effects of the Invention] As described above, according to the present invention, the gap between the mold mating surfaces of the mold is crimped and eliminated, making it possible to prevent the generation of flash, and since the cavity is not pressed, the shape
This has the effect of producing castings with excellent shape and dimensional accuracy without affecting dimensions.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIGS. 3 and 4 are front sectional views showing an example of a conventional mold matching method. It is.

Claims (1)

[Claims] In a mold matching method in which an upper mold is placed with the parting surface facing down on a lower mold that has been placed with the parting surface facing upward, and then the upper mold is pressed from above, the lower mold and the upper mold are pressed together. A mold matching method characterized in that the upper mold is pressed through a pressing plate provided with a through hole having a shape similar to the contour shape on the cutout surface of the formed mold cavity.