JP2002283318A - Split mold for cast molding pottery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a split mold for cast molding a pottery capable of eliminating a cut or a deformation of a molding by preventing the deformation of the mold while reducing in weight the mold. SOLUTION: The split mold for cast molding the pottery is used to cast mold the pottery having a site to become a reverse taper with respect to a mold releasing direction. The split mold comprises a front surface porous layer made of a porous resin having an air permeability/water permeability, a reinforcing layer made of a foamed resin filled in the rear side surface of the porous layer to support and reinforce the porous layer, and an air supply tube communicating with the porous layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slurry casting mold used for casting a ceramic product such as sanitary ware, and more particularly to a split mold for the same.

[0002]

2. Description of the Related Art In general casting of ceramics, a casting slurry is poured into a molding die to deposit the slurry on the mold surface, and if necessary, the remaining slurry is discharged to form a deposition layer. As a result, molded products are obtained. After that, the product goes through drying, glazing and firing processes. Here, among ceramics, sanitary ware products have various types and complicated shapes,
In particular, in order to obtain a molded product having a bowl portion such as a stall urinal, a Western-style toilet, a washbasin, and a handwasher, a core mold (hereinafter referred to as a split mold) may be required in the molding process.

[0003] As a material for the split mold, the same porous resin as that used for the front mold and the back mold has been used in order to ensure ventilation, water permeability and strength. However, in the molding process, it is required to be as light as possible in order for the molding operator to handle the split mold such as detachment. Therefore, in order to reduce the weight of the split mold, a glass cloth 102 is laminated on the inner surface of a porous resin layer 101 formed in a desired shape as shown in FIG. Hollow split molds are used.

[0004]

However, the above-mentioned hollow split mold still has problems to be solved. In other words, although the split mold hollow portion 104 is blocked by the laminated glass cloth 102, there is a minute gap through which air can pass due to its characteristics, and when the mold is removed, the demolded pressurized air may enter. . Although the reinforcing material 103 inside the split mold has resistance to external stress, it does not consider the pressure from the inside, and when air enters the hollow portion 104, as shown in FIG. Since the portion 104 swells and a gap is formed in the mold surface 105 and the casting slurry flows into the gap, the protruding portion 10 of the molded body 107 is taken out when the split mold is removed.
No. 6 was caught, and troubles such as cutting and deformation occurred.

SUMMARY OF THE INVENTION The present invention realizes a mold for casting molding of ceramics, which makes it possible to reduce the weight of the mold and to prevent the mold from being deformed, thereby eliminating the occurrence of cutting and deformation of the molded body. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a split mold for cast molding used for cast molding of ceramics having a portion which is inversely tapered with respect to the demolding direction. The casting mold splitting mold is ventilated
A surface porous layer made of a porous resin having water permeability, a reinforcing layer made of a foamed resin filled on the back side of the surface porous layer to support and reinforce the surface porous layer, and And a communicating air supply pipe. By doing so, the split mold itself becomes lighter, the hollow portion is eliminated inside the split mold, and the deformation of the split mold can be effectively prevented, and the occurrence of cutting and deformation of the molded body can be eliminated. .

In a preferred aspect of the present invention, the reinforcing layer made of foamed resin is formed of urethane foam resin. The urethane foam resin has excellent compressive strength. By forming the foamed resin reinforcing layer with the urethane foam resin, deformation of the split mold can be prevented and the split mold can be reduced in weight.

In a preferred aspect of the present invention, the expansion ratio of the urethane foam resin is 3 to 7 times. If the expansion ratio of the urethane foam resin is 3 times or less, there is no effect on weight reduction, and if it is 7 times or more, the strength is reduced and the strength as a reinforcing material cannot be obtained. Therefore, by setting the expansion ratio to be 3 to 7 times, it is possible to effectively balance the reinforcing strength necessary for preventing deformation of the split mold and the lightness of the split mold.

In a preferred embodiment of the present invention, the surface porous layer is made of a mixture of an epoxy resin and silica sand powder. When the surface porous layer is made of a mixture of epoxy resin and silica sand powder that has good water absorption, the slurry is well deposited on the split mold surface and has appropriate strength against chipping and cracking Therefore, it is possible to achieve both the inking property of the molded body and the prevention of problems such as cutting and deformation.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a portion which is reversely tapered with respect to a removing direction of a molding die is, for example, a bowl portion of a stall urinal, a Western-style toilet, a washbasin, a handwasher or the like. As described above, when the size of the inlet portion is smaller than that of the internal space, and when a molding die for forming the internal space is integrally formed, the portion cannot be smoothly removed. In order to solve this problem, a split type split mold is generally used.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows, as an example, a cross section of a split mold A used for molding a wall-mounted hand-washing machine. The split mold A has a vent formed on its outermost layer according to the shape of the desired molded body.
A surface porous layer 1 made of a porous resin having water permeability;
On the back side surface of the surface porous layer 1, a reinforcing member 2 made of urethane foam resin, which is formed in a shape that can be in close contact, is firmly fixed with a sealing resin 5. After the completion of molding, a hollow air groove (not shown) is formed in the surface porous layer 1 to eject air for releasing from the molding surface 1a of the surface porous layer 1. An air supply pipe 3 connected to the air groove (not shown) passes through the inside of the reinforcing member 2 made of urethane foam resin and leads from the mating surface 4 to the outside of the mold. Here, since the mating surface 4 does not need to be inlaid, it is not necessary to have water absorption, and it is possible to use various members that are smooth, have little deformation, and have durability.

Next, a method of forming the split mold A will be described. First, a slurry obtained by mixing an epoxy resin and silica sand powder at an appropriate ratio is poured into a case mold (not shown) for forming a split mold.
The surface layer 1 is formed by curing. At this time, an air groove (not shown) for supplying demolding air to the surface porous layer 1 and an air supply pipe 3 are provided. Next, a separately prepared case mold (not shown) for forming a reinforcing member 2 made of a urethane foam resin having substantially the same size as the shape of the back surface of the porous surface layer 1 is provided with urethane foam having a desired magnification. To form the urethane foam resin reinforcing material 2.
After the reinforcing member 2 made of urethane foam resin formed in this manner is placed in the split mold forming case mold on which the previously produced surface porous layer 1 is set, the sealing resin 5 is interposed therebetween.
Is poured and cured for a certain period of time, whereby the surface porous layer 1 and the reinforcing material 2 made of urethane foam resin are fixed. By taking this out of the case mold, the split mold A can be manufactured.

Next, a method of forming a wall-mounted hand-washing machine using a casting mold including the split mold A having the above structure will be described with reference to the drawings. As shown in FIG. 2, a casting mold 10 for forming a hand-washing machine having a bowl portion.
Is composed of a front mold C, a back mold D, and a split mold A, and forms a molded body 6 in a casting mold 10 by pouring slurry into a casting space formed when these are assembled. After the molding is completed, in order to prevent the molded body from being deformed or being cut off, air is introduced into the front mold C and the back mold D while leaving the split mold A inside the molded body 6. Then, the front mold C is released in the arrow X direction, and the back mold D is released in the arrow Y direction. Next, as shown in FIG. 3, the split mold A is released from the molded body 6 by removing the mold air and moving in the direction of arrow Z. Here, split mold A
Is reinforced inside with a urethane foam resin reinforcing material 2,
Since no deformation occurs, there is no gap in the mating portion between the split mold A and the front mold C, no protrusion of the slurry occurs, and the mold A can be smoothly removed.

The porous resin used for forming the split mold in the present invention has an appropriate water absorbency for making the sludge satisfactorily deposited and an appropriate air permeability that can be easily released at the time of demolding. It is desirable that the material satisfying these conditions
A variety of things are available. The present applicant has proposed a material in which an epoxy resin and fine silica sand are mixed as a mold material for porcelain molding, for example, in Japanese Patent Publication No. 62-26657. Although this material can be suitably used in the present invention, since silica sand has a higher specific gravity than epoxy resin, a material in which the amount of silica sand is appropriately reduced in consideration of the balance with strength can be suitably used.

The urethane foam resin used as the reinforcing material can be easily formed into a desired shape, has high reinforcing strength, and is lightweight. Further, the expansion ratio of the foamed urethane resin is about 3 to 7 times, which has fluidity at the time of forming a predetermined shape, and has an appropriate strength after solidification. Also, other than urethane foam resin, there is fluidity when forming a predetermined shape,
Any resin having an appropriate strength after solidification can be used.

The present invention can be used for forming all the ceramic products which have a reverse tapered portion such as a stall urinal, a Western-style toilet, a washbasin, and a handwasher, and require a split mold when forming the same.

As described above, the resin casting mold used for pressure casting has been described as an example, but it goes without saying that the present invention can be applied to a gypsum mold if the present invention is appropriately applied.

Hereinafter, the results of a trial production test of a casting mold for a wall-mounted hand-washing machine manufactured by using the technique of the present invention will be described. First, a split mold having a hollow portion formed therein using a conventional technique and reinforced with a glass cloth layer and a wooden reinforcing material is used.
Type 3 was produced. At the same time, using the technology of the present invention, seven molds were produced in which the inside of the surface porous layer was entirely reinforced with a urethane resin reinforcement. The casting mold 20 for a wall-mounted hand-washing machine including these split molds is mounted on a casting molding apparatus, and
With the continuous operation for 4 hours, the occurrence of defective molded bodies was checked for 3 months. Here, in a molded article produced by the mold in three months, a cast and a deformation rate of 0.5% or more due to cutting and deformation of the split mold in the molding process was caused. The mold was defined as a bad mold. The results of the confirmation test are shown in FIG. 5. As for the casting mold using the conventional technique, 7 out of 13 molds were defective, whereas the casting mold using the technique of the present invention was 7. The number of defective molds was zero. As described above, it has been found that the present invention shows a remarkable superiority in the molding of the cast body of the ceramic having the portion which is inversely tapered with respect to the demolding direction of the molding die.

[0019]

According to the present invention, it is possible to reduce the weight of the split mold and prevent the split mold from being deformed, thereby making it possible to eliminate the occurrence of cutting and deformation of the molded article. A split mold can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a split mold according to an embodiment of the present invention.

FIG. 2 is a view showing a molding state of a wall-mounted hand-washing machine according to one embodiment of the present invention.

FIG. 3 is a view showing a detached state of the wall-mounted hand basin according to one embodiment of the present invention.

FIG. 4 is a graph showing the state of occurrence of defective molds.

FIG. 5 is a view showing a sectional structure of a conventional split mold.

FIG. 6 is a view showing a state at the time of molding of a conventional split mold.

[Explanation of Signs] A: Split mold C: Front mold D: Back mold 1, 101: Surface porous layer 1a: Molded surface 2: Reinforcement made of urethane foam resin 3: Air supply pipe 4, 105: Forming surface 5 ... Resin for sealing 6,107 ... Molded body 10 ... Mold for casting 102 ... Glass cloth 103 ... Wooden reinforcement 104 ... Hollow part 106 ... Protruding part

Claims (4)

[Claims] 1. A casting mold for use in the casting of porcelain having a portion which is inversely tapered with respect to the releasing direction, wherein the casting mold is made of a porous resin having air permeability and water permeability. A surface porous layer, a reinforcing layer made of a foamed resin filled on the back side of the surface porous layer to support and reinforce the surface porous layer, and an air supply pipe communicating with the surface porous layer. A split mold for cast molding of ceramics. 2. The split mold according to claim 1, wherein the foamed resin reinforcing layer is formed of urethane foam resin. 3. The mold according to claim 2, wherein the expansion ratio of the urethane foam resin is 3 to 7 times. 4. The surface porous layer is made of a mixture of an epoxy resin and silica sand powder.
The mold for casting of ceramics according to any one of the above.