JP6377409B2 - Mold casting equipment - Google Patents

Description

  The present invention relates to a mold casting apparatus (hereinafter also simply referred to as a “casting apparatus”), and more particularly, to an improvement in a technique for manufacturing a mold as a metal molding (casting) by a casting method.

  In general, a foam molded article made of polyurethane or the like as a raw material is manufactured using a mold obtained by a casting method. However, the mold obtained by the casting method may contain bubbles or foreign substances such as oxides. When polyurethane is foam-molded using such a mold, the polyurethane or bubbles in the mold may become polyurethane. When the foamed molded product is taken out of the mold, the foamed molded product has been broken.

  Casting is manufactured by pouring the raw material into a sand mold having a shape obtained by inverting the target casting shape. Therefore, defects such as bubbles and foreign matters in the casting are cast by casting the raw material into the sand mold. This is considered to be caused by air or foreign matter being caught in the raw material when the product is manufactured. Therefore, in order to prevent the occurrence of defects in the mold, it is important to prevent the entrapment of air and foreign matters when pouring the raw material, but the work of pouring the raw material into the sand mold has been conventionally performed manually by the operator In reality, the actual pouring speed, method, and the like vary from worker to worker.

  On the other hand, in Patent Document 1, for example, in order to make it possible to manufacture a high-quality casting, the molten metal inlet is connected to a container that stores the molten metal, and the molten metal in the container passes through the inlet and the feeder to form a mold cavity. In the mold filling method to be filled in, a technique has been proposed in which the mold is rotated around the horizontal axis of the outlet with the molten metal passage formed at the connection between the outlet and the inlet of the mold open. . However, this method has a problem that a dedicated facility is required and a large amount of capital investment is required.

JP-A-8-090208

  As described above, techniques for minimizing the occurrence of bubbles and foreign matters during casting production, as well as casting defects such as shortage and blowing around the hot water have been studied, but are not sufficient. It was.

  Therefore, the object of the present invention is to significantly reduce the occurrence of various casting defects such as shortage of hot water and blowing, in addition to bubbles and foreign objects, without requiring large capital investment, as compared with the case of conventional manual work. An object of the present invention is to provide a mold casting apparatus that can perform such a process.

  As a result of intensive studies, the present inventors have made it possible to reduce the entrainment of air and foreign matters during the pouring of raw materials by improving the device structure, and to suppress the occurrence of defects in the resulting casting. As a result, the present invention has been completed.

That is, the present invention comprises a mold for casting a mold and a hot water reservoir having a volume equal to or larger than the volume of the metal mold, and the molten metal held in the hot water reservoir is used as a casting port of the hot water reservoir and An apparatus for casting a mold by casting into a cavity in the mold through at least one weir of the mold,
A lid portion that allows the molten metal flow path to be opened and closed is provided at any part from the pouring port to the weir, and the shape of the lid portion is a rectangular flat plate shape or a circular flat plate shape. And a runner connecting the weir, the runner comprising a vertical portion extending downward from the casting port and a horizontal portion extending from the lower end of the vertical portion toward the weir. At least two or more are provided, and the horizontal portion of the runner extends from the lower end of the vertical portion to branch to the at least two or more weirs.

  In the casting apparatus of this invention, it is preferable that the cross-sectional shape of the said horizontal part of the said runner is a rectangular shape in which the width | variety is formed larger than height.

  Moreover, in the casting apparatus of this invention, it is preferable that the said cover part is provided in the said casting port or the said dam. Furthermore, in the casting apparatus of the present invention, it is preferable that an opening area of the casting port is larger than a total opening area of the weirs.

  According to the present invention, it is possible to significantly reduce the occurrence of various casting defects such as shortage of hot water and blowing, in addition to bubbles and foreign objects, without requiring large capital investment, compared to the case of conventional manual work. This makes it possible to realize a mold casting apparatus that can be used.

It is a schematic sectional drawing which shows one structural example of the casting apparatus of the metal mold | die of this invention. It is explanatory drawing which takes out and shows the flow path part of the molten metal in the casting apparatus of the metal mold | die of this invention. It is explanatory drawing which takes out and shows the flow path part of the molten metal which concerns on other embodiment of the casting apparatus of the metal mold | die of this invention. It is explanatory drawing which takes out and shows the flow path part of the molten metal which concerns on the conventional casting apparatus of a metal mold | die.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic sectional view showing an embodiment of a mold casting apparatus of the present invention. Moreover, FIG. 2 is explanatory drawing which takes out and shows the flow path part of the molten metal which concerns on one Embodiment of the casting apparatus of the metal mold | die of this invention. The mold casting apparatus of the present invention shown in the figure includes a mold 10 for mold casting, a hot water reservoir 20 having a volume equal to or larger than the volume of the metal mold, a pouring port 21 of the hot water reservoir 20 and a weir 11 of the mold 10. And a runner 30 that connects the two and the molten metal held in the hot water reservoir 20 is cast into the cavity 12 in the mold 10 through the casting port 21, the runner 30, and the weir 11. The mold is cast. In the figure, reference numeral 13 denotes a feeder part.

  In the casting apparatus of the present invention, it is important that a lid 40 that can open and close the molten metal flow path is provided at any part from the casting port 21 to the weir 11. In the example shown in FIG. 1, the lid 40 is provided so that the casting port 21 can be opened and closed. The hot water reservoir 20 is provided above the casting port 21, and the lid 40 that can be opened and closed is provided in any part from the casting port 21 to the weir 11 in this way, so that the discharge of the molten metal can be controlled. Thus, after the molten metal is once held in the hot water reservoir 20 or in the hot water reservoir 20 and the runner 30, it can be cast into the mold 10 in a drop of gravity. Therefore, in the present invention, since only the step of opening the lid portion 40 can be quickly cast at a constant speed without depending on the skill of the operator, it is possible to entrap bubbles and foreign matters compared to the conventional case. It is possible to reduce the occurrence of the above and to manufacture a high quality mold. Moreover, since this invention can be implemented only by adding the hot water sump part 20 and the cover part 40 with respect to the casting equipment of a conventional structure, a big capital investment is not required. Furthermore, in the present invention, since the lid portion 40 is provided so that the flow path of the molten metal can be opened and closed, after confirming the completion of casting, the lid portion 40 immediately closes the flow path, so that the hot water reservoir 20 There is also a merit that the molten metal remaining inside can be secured.

  That is, as shown in FIG. 4, in the conventional casting apparatus, the molten metal is cast into the mold 110 from the casting port 121 through the flow path of the runner 130, the weir 111, and the cavity (product part) 112. This casting is generally a drop-type pouring from a ladle, etc., so the molten metal is insufficiently filled (insufficiency in hot water) due to air entrainment (bubbles and oxide formation) when the molten metal falls and insufficient casting speed. ). That is, the occurrence of casting defects is likely to be affected by the skill of the operator who performs pouring. On the other hand, in the present invention, the hot water reservoir 20 that once holds an amount of molten metal sufficient for casting of the mold is provided at the upper part of the casting port 21, and therefore the molten metal is temporarily added to the hot water reservoir 20. After the accumulation, the lid 40 is opened, and the molten metal in the hot water reservoir 20 can be filled into the mold 10 in a short time in a short time.

  According to the present invention, since the time required for casting can be shortened as compared with the prior art, the time for the molten metal to come into contact with the air is reduced, and it is difficult for air bubbles and foreign substances to be caught in the molten metal, and insufficient hot water is hardly generated. Become. In addition, since the molten metal is once stored in the hot water reservoir 20, before the lid 40 is opened, bubbles and foreign matters caught in the molten metal when pouring into the hot water reservoir 20 are floated and separated in the hot water reservoir 20. The amount of bubbles and foreign matters in the molten metal can be further reduced. Furthermore, since the casting time is shortened, the time for the molten metal to contact the sand mold forming the cavity 12 in the mold 10 can also be shortened, so that an increase in the hydrogen concentration in the molten metal can be suppressed. For example, when a molten aluminum alloy is used, by setting the hydrogen concentration in the molten metal to 0.8 ml / 100 g Al or less, bubbles having a diameter of 0.3 mm or more are less likely to be generated in the mold. Problems such as urethane foam adhering to the bubbles and tearing the foamed molded product can be solved. In addition, since the magnitude | size of the bubble to generate | occur | produce becomes small, so that the hydrogen concentration in molten metal is low, it is preferable.

  In the embodiment shown in FIG. 2, the lid 40 is provided on the inner side of the hot water reservoir 20 so that the casting port 21 can be opened and closed. In this case, the molten metal is stored in the hot water reservoir 20 with the casting port 21 closed by the lid 40, and then the lid 40 is removed from the casting port 21 and the casting port 21 is opened to open the hot water reservoir 20. The molten metal inside can be discharged from the casting port 21 into the runner 30 at once. As shown in the figure, the lid 40 has a flat plate shape, and a handle 41 as a handle is integrally provided on one surface thereof. Therefore, the operator can easily open and close the casting port 21 by holding the handle 41 and moving the lid 40. As the shape of the lid portion 40 in this case, it is only necessary that the casting port 21 can be closed. When the lid portion 40 is a circular flat plate shape, even when the handle portion 41 rotates when closing the casting port 21, the direction of the lid portion 40 does not matter. There is an easy advantage. In the illustrated example, the handle portion 41 is provided on the lid portion 40 so that the lid portion 40 can be manually operated. However, the lid portion may be opened and closed by remote operation as electric or air drive.

  In the present invention, from the viewpoint of maintaining the temperature of the molten metal, it is preferable to use a highly heat insulating material for the hot water reservoir 20. It is also effective to make the heat capacity of the hot water reservoir 20 as small as possible.

  In the casting apparatus of the present invention, the opening area of the casting port 21 is preferably larger than the sum of the opening areas of the weirs 11. Thereby, generation | occurrence | production of the vortex | eddy_current in the flow part of the molten metal between the casting port 21 and the weir 11 can be suppressed, and the effect which suppresses mixing of the bubble from air | atmosphere can be acquired. In particular, in the embodiment shown in FIG. 2, after removing the lid 40 from the casting port 21, the molten metal can be quickly filled into the runner 30, and new bubbles and oxidation immediately after the start of pouring can be performed. Generation | occurrence | production of the thing of an object can be suppressed more effectively.

  Furthermore, in the casting apparatus of this invention, as shown to FIG.2, 3, it is preferable that the runner 30 has a part from which the flow-path cross-sectional area becomes small gradually toward a downstream. Thereby, after removing the cover part 40 from the casting port 21, the molten metal can be more reliably filled into the runner 30 without remaining bubbles, and new bubbles and oxides are entrained immediately after the start of pouring. Can be more effectively suppressed. In the example illustrated in FIG. 2, the runner 30 partially includes a portion where the flow path cross-sectional area gradually decreases toward the downstream side. Further, in the example shown in FIG. 3, the flow passage cross-sectional area of the runner 30 gradually decreases toward the downstream side over the entire length of the runner 30.

  Furthermore, in the casting apparatus of the present invention, as shown in the figure, at least one dam 11 is provided in the lower part of the mold 10, for example, 1 to 6, for example, two in the illustrated example. It is preferable. By letting the molten metal be cast from the lower part of the mold, it is possible to more reliably suppress the occurrence of bubbles and foreign substances. Here, as shown in the figure, the lower portion of the mold 10 means the vicinity of the bottom surface of the mold 10 as much as possible. For example, the bottom surface of the cavity 12 in the mold 10 and the bottom surface of the flow path in the runner 30. Is a position where and match.

  FIG. 3 is an explanatory view showing the flow path portion of the molten metal according to another embodiment of the mold casting apparatus of the present invention. In another embodiment of the present invention shown in FIG. 3, a lid 80 is provided on the inner side of the runner 70 so that the weir 51 can be opened and closed. In this case, after the molten metal is stored in the hot water reservoir 60 and the runner 70 with the weir 51 closed by the lid 80, the lid 80 is removed from the weir 51 and the weir 51 is opened, whereby the hot water reservoir 60. In addition, the molten metal in the runner 70 can be directly discharged from the weir 51 directly into the cavity 52. In this embodiment, the amount of entrainment of bubbles and foreign matters can be further reduced from the state immediately after the start of pouring by storing the molten metal up to a position close to the weir 51 which is the boundary surface between the mold 50 and the runner 70. it can. In addition, the code | symbol 53 in a figure shows a feeder part, 61 shows a pouring opening, and 81 shows a handle part.

  In the present invention, any part from the casting port to the weir may be provided with a lid that can open and close the flow path of the molten metal, thereby reducing the occurrence of various casting defects. The casting apparatus can be made. For example, in the embodiment shown in FIGS. 1 and 2, it is the boundary surface of the molten metal flow path between the runner and the mold from the casting port that is the boundary surface of the molten metal flow path between the hot water reservoir and the runner. A lid that can freely open and close the molten metal flow path is provided at any part up to the weir. However, in the present invention, the pouring port can be directly connected to the weir. And the weir can be closed by a lid. Moreover, a cover part may be provided in two or more places, for example, can be provided in both a casting port and a weir.

Hereinafter, the present invention will be described in more detail with reference to examples.
A mold for producing a polyurethane foam molded article was manufactured using a casting apparatus in accordance with the conditions shown in the following table. The dimensions of the mold (casting) were a lunch box type container (melt mass: about 42 kg) having a width of 700 mm × length of 500 mm × height of 200 mm and a thickness of 20 mm. As a casting alloy, an aluminum alloy AC2B (Si: 7% by mass, Cu: 2.2% by mass, Mg: 0.4% by mass, Fe: 0.7% by mass, remaining amount: Al) was used. The casting temperature was 720 ° C. (after degassing by the SNIF method).

  In each example and comparative example, a mixture of silica sand and furan resin (self-curing sand mold) was used as a mold material. Prior to casting, the mold material was brush-coated on the surface of each mold and dried. Moreover, in each casting apparatus, the molten metal mass in the runner from the casting port to the weir was about 15 kg, and the hot metal part was φ100 mm × height 300 mm × 4 pieces (total mass of molten metal: about 25 kg).

  The casting apparatus of Example 1 was provided with a mold, a hot water reservoir, and a runner that connected between the casting inlet of the hot water reservoir and the weir of the mold, and was provided with a lid that could freely open and close the casting inlet. . Moreover, in the casting apparatus of Example 1, two weirs were provided in the lower part of the mold, and the runner had a portion in which the channel cross-sectional area gradually decreased toward the downstream side. On the other hand, the opening area of the casting port was smaller than the total opening area of the weirs.

  The casting apparatus of Example 2 had the same configuration as the casting apparatus of Example 1 except that the opening area of the casting port was larger than the sum of the opening areas of the weirs.

  In the casting apparatus of Example 3, a single weir is provided at the lower part of the mold, and the cross-sectional area of the runner gradually decreases toward the downstream side over the entire length of the runner, so that the casting port can be opened and closed freely. Instead of the lid, the configuration was the same as that of the casting apparatus of Example 2 except that the weir was provided with a lid that could be freely opened and closed.

  The casting apparatus of Comparative Example 1 does not have a hot water reservoir and a hanging weir, and performs casting by dropping pouring into the casting port. The runner gradually moves toward the downstream side of the cross-sectional area of the flow path. It had the same configuration as the casting apparatus of Example 3 except that it did not have a smaller portion.

  For the casting apparatus of each example and comparative example, the time taken to complete casting was measured, and after the surface of the obtained casting was sandblasted, the casting defects on the casting surface were visually confirmed, and the number Was measured. Defects with a size of about φ0.3 mm or less that are difficult to visually confirm were excluded from the count. These results are shown in the table below.

＊１）比較例１については、欠陥が群落状に発生しており、個別のカウントが困難であったため、欠陥数のカウントを途中で断念した。

* 1) In Comparative Example 1, since defects occurred in a community and individual counting was difficult, the number of defects was abandoned halfway.

  As is clear from the results in the above table, in the casting apparatus, a hot water reservoir is provided, and a lid that can open and close the molten metal flow path is provided in any part from the casting port to the weir. As a result, it was confirmed that casting can be completed in a short time compared to the conventional case, and as a result, the number of casting defects in the casting can be easily and greatly reduced. In particular, it can be said that the significance of this technology is extremely great in the field of casting production where generation of casting defects is disliked.

10, 50, 110 Mold 11, 51, 111 Weir
12, 52, 112 Cavity 20, 60 Hot water reservoir 21, 61, 121 Pouring port 30, 70, 130 Runner 40, 80 Lid 41, 81 Handle

Claims (5)

A mold for casting the mold, and a sump portion having a volume equal to or larger than the volume of the mold, and the molten metal held in the sump portion is poured into at least one of the casting port of the sump portion and the mold. An apparatus for casting a mold by casting into a cavity in the mold through a weir,
A lid portion that allows the molten metal flow path to be opened and closed is provided at any part from the pouring port to the weir, and the shape of the lid portion is a rectangular flat plate shape or a circular flat plate shape. And a runner connecting the weir, the runner comprising a vertical portion extending downward from the casting port and a horizontal portion extending from the lower end of the vertical portion toward the weir. Casting of a mold, wherein at least two or more are provided, and the horizontal portion of the runner extends from the lower end of the vertical portion to branch to the at least two or more weirs. apparatus.   The mold casting apparatus according to claim 1, wherein a cross-sectional shape of the horizontal portion of the runner is a rectangular shape having a width larger than a height. The lid, die casting apparatus according to claim 1, wherein is provided in the casting port. The lid, die casting apparatus of any one of claims 1 to 3 which is provided on the weir. The mold casting apparatus according to any one of claims 1 to 4 , wherein an opening area of the casting port is larger than a sum of opening areas of the weirs.

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