JPH02280942A - Method for charging molding sand - Google Patents

Abstract

PURPOSE:To manufacture a mold which can produce a casting having good dimensional accuracy by charging molding sand into neighborhood of a pattern and corner part of a flask in priority from upper part of a shelting member of which the outline shape is similar with the pattern arranged above a parting plane of the pattern laid in the flask. CONSTITUTION:After laying the flask 3 while surrounding the pattern 1 on the pattern surface plate 2, the roof-shaped shelting member 7 having the projection shape a little smaller than the projection shape of the pattern 1 is set at a little higher position from the upper part of the flask 3 above the pattern 1. Successively, the molding sand 4 having 3.5% water content is charged from upper part and at first, dropped to the space between the periphery of the pattern 1 and inside of the flask 3 and piled, and after that, such condition is made that the upper face part of the pattern 1 is covered and the center part thereof is recessed. Successively, after executing fastening of the mold with divided squeeze heads, the pattern is released to complete the molding of the mold 3. In this result, the fastening at vertical part and corner part of the mold is improved and the wholly uniformly fastened mold is obtd. Therefore, the casting cast in this mold having improved dimensional accuracy and excellent quality, is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for introducing molding sand for molding when molding bond molds used in manufacturing pickles.

[Conventional technology]

Conventionally, as shown in FIG. 4, a mold for manufacturing castings is manufactured by mounting a horizontal surface plate 2 on which a horizontal mold 1 is arranged on a table d of a molding machine, and placing a frame 3 on the horizontal surface plate 2. Casting sand 4 in a sand tank (not shown) provided above within this frame 3
After charging, the molding sand 4 is compressed by the squeeze head 5 of the molding machine and the mold is clamped, and then the horizontal mold 1 is removed and molded to form both the upper mold and the lower mold.

According to the conventional molding method described above, when the 1N sand 4 is pressurized with uniform pressure by the squeeze rod 5, the mold tightening of the upper surface parts 1a and lb of the horizontal mold 1 is good, but the horizontal surface plate The upper surface s2a of 2 and the side surface 1c of the horizontal mold 1 have poor mold tightness, especially the corner portion 4a between the horizontal surface plate 2 and the model 1.
The corner portion 4b between the horizontal surface plate 2 and the flask 3 has the worst mold tightness.

If there is a portion where the mold is poorly clamped, there is a risk that the mold may fall off during mold cutting, and in particular, the corner portions 4a often fall off, resulting in poor mold cutting.

In addition, mold tightness is poor (if there is a part where the mold smoothness is low, mold tension will occur in that part after pouring, deteriorating dimensional accuracy, and bonding will occur in the corner part 4a). Decrease the quality of pickles.

In order to improve the above-mentioned uneven mold tightening, a multi-squeeze head molding machine was developed that divides the squeeze head into multiple parts and pressurizes the molding sand in the flask evenly in each part. (see, for example, Japanese Utility Model Publication No. 18969/1983), and has recently come into general use, with some effects being obtained.

[Problem to be solved by the invention]

However, even when molding is performed using the above-mentioned multi-squeeze head molding machine, the mold tightening at the corner portions is not sufficient, and mold dropouts and mold bulges occur, resulting in poor dimensional accuracy and poor pickle quality. is decreasing.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a method for charging molding sand to form a mold that can produce pickles with good dimensional accuracy.

[Means to solve the problem]

In order to achieve the above object, as a result of various studies, it has been found that in order to achieve uniform mold clamping, it is important to pour as much sand as possible into the poorly clamped areas.

In other words, we have found that if we focus on pouring the molding sand into the area near the flask ring of the flask around the horizontal mold, other than the part that comes into contact with the horizontal mold, we can achieve sufficient mold tightening down to the corners of the mold. .

That is, the present invention has been made based on the above findings, and consists of placing a casting flask surrounding the horizontal mold on a horizontal surface plate on which a horizontal mold is arranged, and a sand tank provided above within the flask. When pouring in the foundry sand, an appropriate shielding member having a shape similar to the contour shape on the parting surface of the model is provided above the horizontal mold, and the foundry sand is dropped from above the shielding member to cover the surroundings of the horizontal mold. This method is characterized by intensively pouring sand into the ring of the top frame.

[For production]

The molding sand injected from above the shielding member first hits the shielding member and does not fall directly onto the horizontal mold, but instead falls and accumulates around it and between the horizontal mold of the flask frame ring, and then deposits on the upper surface of the horizontal mold. cover.

Therefore, the molding sand is sufficiently supplied to the periphery of the model and the ring part of the casting flask and becomes dense, so by clamping the mold with the multi-squeeze head molding machine, it is sufficient and nearly all the way to the corners. This results in a uniformly compacted mold.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

First, a horizontal mold 1 having the dimensions shown in FIG. 3 and having a draft angle of 2° was attached to a horizontal surface plate 2, and this was mounted on the table of a multi-squeeze head molding machine (not shown).

Next, as shown in FIG. 1, after placing the casting flask 3 on the horizontal surface plate 2 surrounding the horizontal mold 1,
A roof-shaped shielding member 7 having a planar shape slightly smaller than the planar shape of the model is provided at a position slightly higher than the upper edge of the model.

Next, foundry sand 4 having a moisture content of 3.5% was charged from an upper sand tank (not shown). The molding sand 4 first fell and accumulated between the periphery of the horizontal mold 1 and the inside of the flask 3, and then covered the upper surface of the model 1, causing the medium-heated portion to become depressed.

Next, the mold was clamped using a divided squeeze head (not shown), and then the mold was removed to complete the molding of the mold 8.

The mold 8 was turned over so that the surface in contact with the model surface plate 2, that is, the parting surface 9 was facing upward, and the mold hardness was measured using a mold hardness meter for each surface A-H shown in FIG. Table 1 shows the comparison between the results and the conventional method of pouring sand directly from a sand tank and then molding.

Table 1 As can be seen from Table 1, the mold obtained by the method of the present invention, which was molded after introducing maimono sand, had a deep surface (A
The mold tightness of D) is improved compared to the conventional method in which maimono sand is added, and the shallow surface is rather reduced, making the mold tightness more uniform overall.

In particular, the mold tightness at the corners (G, H) has been improved, mold chips are prevented from falling off during mold removal, and the nearly vertical and deep surfaces with a 2° draft angle (E, F) Mold tightening has also been improved.

It is clear that the castings produced by such molds are of excellent quality such as good dimensional accuracy.

〔Effect of the invention〕

As described above, according to the present invention, the mold clamping 9 at the vertical and corner parts of the mold is improved, and a mold with uniform mold clamping as a whole can be obtained, so that the dimensional accuracy of the cast product is improved. It has great industrial effects, such as the ability to obtain products of excellent quality.

In addition, although the above explanation is for one filled mold, when manufacturing multiple filled molds, a shielding member is placed on each horizontal mold, and for example, each shielding member is connected with a connecting member to form the whole. If they are integrated, and when the deaf sand is put in, the whole thing moves at the same time so that each one is positioned on each horizontal mold (not shown), and the same effect as when one piece is included can be achieved. Further, the shape of the shielding member is not limited to the roof shape, but may be a conical shape or other shape suitable for a wedge shape.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) show an embodiment of the present invention,
(a) is a front sectional view, and (b) is a plan view of FIG. 1. Figure 2 is a cross-sectional view of the mold after being molded and reversed;
The figure is a perspective view of the horizontal type used in the example, and FIG. 4 is a sectional view showing an example of a conventional molding method. 1: ffl[mold, 2: horizontal surface plate, 3: casting flask,
4: IL material, 7: Shielding member, S: @ type agent Patent attorney Takashi Honma IhI Figure (a) 3rd / /Sri (b) Figure 4 Figure Z

Claims (1)

[Claims] A casting flask is placed on a horizontal surface plate on which a horizontal mold is arranged, surrounding the horizontal mold, and when pouring molding sand in a sand tank provided above into the casting flask, a horizontal mold is placed above the model. A method for introducing foundry sand, comprising: providing a suitable shielding member having a shape similar to the contour shape on a parting surface, and introducing the foundry sand from above the shielding member.