JPH0580301B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for installing a ceramic filter in a casting mold. An object of the present invention is to reliably attach a ceramic filter without any gaps, thereby reliably separating inclusions contained in molten metal, and producing high-quality castings.

(Prior Art) A ceramic filter is a porous body made of a refractory material. Ceramic filters can be used as filters, or filters, because their cells are interconnected. Therefore, we added a ceramic filter to the casting mold. During casting, inclusions in the molten metal are separated using a ceramic filter.

The ceramic filter that is attached to the casting mold is used as it is after it has been molded into that shape. In other words, ceramic filters cannot be made by making a large block of porous material and later cutting it to a predetermined size. The reason for this is that ceramic filters are made of a three-dimensional fine mesh skeleton and are easily broken, making it difficult to obtain accurate dimensions by cutting them out. This is because chips remain in the filter, which may clog the holes or get mixed into the filter, making the filter less effective.

The following method is used to mold ceramic filters. First, a porous body made of an organic material such as a urethane sponge is used as a base material, and a slurry of ceramic powder is attached to this and dried and solidified to form a ceramic coating. This coating is then fired to carbonize and burn off the organic material, leaving only the porous ceramic body behind. The ceramic porous body thus obtained has substantially the structure and size of the porous body made of an organic material as the base material. However, since porous bodies made of organic materials are themselves flexible and expandable, it is difficult to trim them accurately. In addition, some deformation and shrinkage occur during firing. Therefore, it has been difficult to properly align the dimensions of porous ceramic bodies.

Since it is difficult to ensure uniform dimensions of ceramic filters, special ingenuity was required to install them within the mold. The reason for this is that the ceramic filter must be installed so that there are no gaps around it. Furthermore, since at least one ceramic filter needs to be attached to each mold, it must be easy to attach.

Therefore, a ceramic filter has conventionally been attached to a mold as shown in FIG. 3. In Figure 3,
Figure a is a partially cutaway vertical cross-sectional view of the mold, and figure b is a horizontal cross-sectional view taken along line BB in figure a. The mold is made by bringing an upper mold 1 and a lower mold 2 into close contact at the mating surfaces XX. The runner is formed by forming a recess 3 in the mating surface XX of the lower mold 2 and communicating the recess 3 with a hole 4 provided in the upper mold. In that case, ceramic filter 5
was installed by fitting it into the recess 3 of the lower mold with the upper mold 1 removed.

Molten metal is flowed in the direction of arrow P within the mold. Therefore, in order to eliminate gaps and ensure the passage of molten metal, the ceramic filter 5 must be in close contact with the wall surface of the recess 3 relative to the lower mold 2, and
The upper die 1 must be in close contact with the wall of the hole 4. Therefore, conventionally, in the lower mold 2, the recess 3
Steps 31 and 32 are provided on the wall surface of the ceramic filter 5, and the corner surface 51 of the ceramic filter 5 is located at the tip of the flow.
are brought into close contact with the side surface 32, and step portions 41 and 42 are also provided on the wall surface of the hole 4 in the upper mold 1, so that the step portion 42
I brought Nicomen 51 up close.

However, it may not be easy to provide the stepped portions 41 and 42 in the upper mold 1 and to align the upper mold 1 with the lower mold 2 so that the stepped portions 41 and 42 are in close contact with the corners of the ceramic filter 5. . This is because it is difficult to see the positional relationship between the corners of the ceramic filter 5 and the stepped portions 41 and 42 when fitting the partial molds together. In addition, the corner of the ceramic filter 5 is connected to the mating surface X-X.
Since it protrudes from the surface, it is easy to hook the mating surface
Otherwise, the upper die 1 would be damaged, and the number of inclusions would increase. On the other hand, if it was too far away, a gap would be created, which would worsen the overeffect.

Therefore, in order to avoid damage to the ceramic filter 5, conventionally, as shown in FIG.
It was decided not to provide a stepped portion, and the upper end of the ceramic filter 5 was positioned lower than the mating surface XX. In other words, it has been decided that it is unavoidable that a small gap will occur, and efforts have been made to make the gap as small as possible. However, this was not enough to ensure that the mistake was made.

(Problems to be Solved by the Invention) The object of the present invention is to easily install a ceramic filter at the seam of molds without any gaps so that molten metal can completely pass through.

(Means for solving the problem) In order to achieve the above object, the present invention assumes the structure shown in FIG. It is intended to be closed with a core.

That is, the present invention uses a partial mold in which a hole for a runner is opened on the mating surface and a partial mold in which a recess for the runner is formed in the mating surface, and a ceramic filter is fitted in the middle of the recess. Later, in the method of making a mold by bringing the mating surfaces close together and communicating the runner hole and the runner depression, before bringing the mating surfaces together, a ceramic filter is pulled from the mating surfaces and placed in the depression. Place the core on the surface of the ceramic filter located at the tip of the flow of hot water in the runner, and touch the core to the corner of the ceramic filter located near the surface that straddles the runner. It is characterized by straddling the runner and fixing the surface of the core flush with the mating surface.
This invention relates to a method of installing a ceramic filter in a mold.

(Example) An example of implementing the method of the present invention will be described below based on the drawings. FIGS. 1 and 2 show the main parts of a mold made by the method of this invention. Figure a is a vertical cross-sectional view of the mold, figure b is a cross-sectional view taken along line B-B in figure a, and figure c is a cross-sectional view taken along line C-C in figure a.

In FIG. 1, an upper mold 1 and a lower mold 2 are constructed in the same manner as the conventional mold shown in FIG. In addition, in FIG. 1, the ceramic filter 5 is placed in the fourth
It is fitted in the same way as the conventional mold shown in the figure. The only difference between the mold shown in Fig. 1 and the mold shown in Fig. 4 is that a core 6 is added and a notch 7 is formed in the lower mold to support both ends of the core 6. It is.

In FIG. 1, the mold includes an upper mold 1 having a runner hole 4 opened on the mating surface
and a lower mold 2 forming a recess 3 for a runner. A ceramic filter 5 is fitted in the middle of the recess 3, and the ceramic filter 5 is retracted from the mating surface XX. The hot water in the runner flows in the direction of arrow P, but on the surface of the ceramic filter 5 located at the end of the flow of hot water, there is a middle part in the corner part 51 located near the mating surface X-X that straddles the runner. child 6 is in contact with it.
The core 6 extends across the runner, has a surface 61 that is in close contact with the surface of the ceramic filter, and a surface 62 that is in close contact with the surface of the ceramic filter.
is flush with the mating surface XX, and both ends are fitted into the notches 7 of the recess 3 and fixed.

The core can be made of the same material as the upper mold 1 or the lower mold 2. That is, it is made by adding an organic or inorganic binder to sand and shaping it into a rod shape as shown in FIG. It goes without saying that the core does not allow molten metal to pass through it, since it does not have a porous body.

As shown in FIG. 1, the core 6 preferably has a flat surface 61 that is in close contact with the ceramic filter 5 and a flat surface 62 that is flush with the mating surface. The plane 61 and the plane 62 are usually orthogonal in many cases. In addition, the surface 6 of the core 6 that is in contact with the molten metal flow
3 preferably has an inclination that expands in the flow direction. This is to prevent the flow of molten metal passing through the ceramic filter 5 from being obstructed.

The core 6 is attached across the runner. In other words, the core 6 has its flow direction extending perpendicularly to the flow direction of the molten metal, and both longitudinal ends are supported by both side walls of the runner. In order to support the core 6, both side walls of the recess 3 are cut out 7 in the cross-sectional shape of the core 6. The upper surface 62 of the core 6 is flush with the mating surface XX.

In this way, when the core 6 is attached, the ceramic filter 5 is located lower than the mating surface of the lower die 2, and the ceramic filter 5 is flush with the mating surface of the lower mold 2. You will be surrounded. Therefore, when the upper mold 1 is placed on the lower mold 2, the mating surfaces of the upper mold 1 and the lower mold 2 will easily come into close contact, and all that is left to do is to match the holes 4 and the depressions 3. . Furthermore, even if the holes 4 and the depressions 3 are slightly different from each other, all of the molten metal flowing from the holes 4 to the depressions 3 will pass through the ceramic filter 5, causing no problem. Therefore,
The ceramic filter 5 can be easily installed, and the result is that the ceramic filter 5 can reliably pass the molten metal.

In Figure 1, the core 6 is inserted into the ceramic filter 5.
Although only one core 6 is provided on the surface of the core 6, the installation of the core 6 is not limited to this. As shown in FIG. 2, one core 6 may be provided on each of the two opposing surfaces of the ceramic filter 5. It goes without saying that the surface 62 of the core 6 must be flush with the mating surface XX.

In addition, in Figure 2, figure a is A-A in figure b.
Since the cross-sectional view is taken along the line, the ceramic filter 5 appears to be floating in the air, but the cross-sectional view taken along line C-C in figure a is as shown in figure c. , both the filter 5 and the core 6 are supported by the lower die 2.

(Effects of the Invention) According to the method of the invention, a partial mold having a hole for a runner formed on the mating surface and a partial mold having a recess for the runner formed on the mating surface are used. Since the ceramic filter is fitted and retracted from the mating surfaces, the mold can be made by bringing the mating surfaces into close contact without damaging the mold or the ceramic filter. In addition, the core was placed in contact with the surface of the ceramic filter located at the end of the flow of hot water in the runner, and the core was fixed by straddling the runner.
The core prevents the ceramic filter from being moved by the flow of hot water, and therefore the ceramic filter is firmly fixed. In addition, the core straddles the runner and touches the corner of the ceramic filter located near the mating surface, and the surface of the core is flush with the mating surface, so the core is in contact with the ceramic filter and the mating surface. This completely closes the gaps that occur between the two, thus ensuring that all of the molten metal passes through the ceramic filter, resulting in complete filtration. Moreover, it is sufficient to install both the ceramic filter and the core in the recess, and when installed, the ceramic filter is surrounded by a flush surface due to the attachment of the core. As long as the opening is located within the above-mentioned enclosed area, there will be no leakage of hot water, making it easier to join the partial molds together and, in turn, make it easier to attach the ceramic filter. The inventive method provides these benefits.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of molds made according to the present invention. 3 and 4 are cross-sectional views of molds made by the conventional method. In each figure, figure a is a vertical sectional view, figure b is BB in figure a.
FIG. Moreover, figure c of FIG. 2 is a sectional view taken along the line CC in figure a of FIG. 2. In each figure, 1 is an upper mold, 2 is a lower mold, X--X lines are mating surfaces of the molds, 3 is a depression, 4 is a hole, 5 is a ceramic filter, 6 is a core, and 7 is a notch.

Claims (1)

[Claims] 1 Using a partial mold with holes for runners on the mating surfaces and a partial mold with a recess for the runner on the mating surfaces, insert a ceramic filter in the middle of the recess, and then press the mating surfaces together. In the method of forming a mold by bringing the runner holes and the runner depressions into communication with each other, before bringing the mating surfaces into close contact with each other, a ceramic filter is retracted from the mating surfaces and placed in the depression. On the surface of the ceramic filter located at the tip of the flow of hot water in the path, touch the core to the corner of the ceramic filter located near the surface that straddles the runner, and place the core astride the runner. A method of installing a ceramic filter in a mold, which is characterized by fixing the surface of the core flush with the mating surface.