KR900001603B1 - Method of making mold used in pressure slip casting - Google Patents

Abstract

The production process for a mould being used in a pressure slip casting process for ceramic articles is as follows. Two or more porous part-moulds are constructed, each designed to form a filter layer and comprising water and air ducts; the intended lower mould is placed inverted on a block and an open metal box is placed around it, then the half-mould and the top of the block is coated with a parting agent. The outside of this half-mould and the coating of the parting agent are covered with a sealing synthetic resin.

Description

Manufacturing method of pressure injection molding mold of ceramics

1 is a cross-sectional view of a porous mold made by one of the methods of the present invention.

2 is a schematic representation of a conduit formed in a porous form.

3 is a perspective view of an upper case used in a method according to the first aspect of the invention.

4 is a cross-sectional view showing a state in which the upper case is connected to the base and forms a mold cavity for forming a slurry therebetween.

5 is a partial cross-sectional view of an upper case having a retaining member for attaching a flexible line to the upper case.

6 is a cross sectional view of the porous die with a base and a top case removed.

7 is a cross-sectional view of the porous die in a state where the hole is filled with resin at the position where the holding member is located.

8 is a cross-sectional view of the porous mold from which the flexible line is extracted.

9 is a perspective view of an upper case used in a method according to the second aspect of the invention.

FIG. 10 is the same as FIG. 4 except that the upper case of FIG. 9 is used, and FIG. 11 is a cross-sectional view of the holding member for attaching the upper case and the flexible line to the upper case.

12 is a top plan view and a front view of one of the holding members.

FIG. 13 is the same as FIG. 10 except that the upper case is removed, and FIG. 14 is a sectional view of the porous type filled with resin at the place where the retaining member was located.

15 is a cross-sectional view of the porous mold from which the flexible line is extracted.

FIG. 16 is similar to FIGS. 4 and 10 but shows a state in which a porous type is produced by the method according to the third aspect of the present invention, and FIG. 17 is similar to FIG. 16 but on an enlarged scale with the upper case and soft rubber 18 shows an upper plan view and a front view of a retaining member for use with a soft rubber member.

19 is similar to FIG. 16 but shows a state in which the upper case is being removed, and FIG. 20 is a partial sectional view of the porous type in which the soft rubber member is being removed.

Fig. 21 is a sectional view of the porous mold in which holes are filled with resin at the place where the holding member is located.

22 is a cross-sectional view of the porous mold from which the flexible line is extracted.

23 is a perspective view of an upper case used in a method according to the fourth aspect of the invention.

FIG. 24 is a cross sectional view in which a porous mold is manufactured using the upper case of FIG.

FIG. 25 is a view similar to FIG. 24 with a line drawn out. FIG.

Figure 26 is a perspective view of the relationship between the rigid and flexible lines.

27 is a partial cross-sectional view of the porous die.

28 is a perspective view of the porous type in which the ends of the branch channels are closed with resin.

And FIG. 29 is a cross-sectional view of a state in which a plurality of channels in the porous mold are independent of each other and do not communicate with each other.

FIELD OF THE INVENTION The present invention relates to a method for producing a porous mold used for pressure slip casting of ceramic articles.

In order to manufacture most ceramic articles having a large and complicated shape, a pressureless injection molding method using a plaster mold has been adopted for a long time. However, in the injection molding method, since water is absorbed from the slip into the mold by capillary action, the molding rate cannot be resolved firmly. When the gypsum mold is saturated with water, its capillary action is weak and should be dried for a long time after every one or two uses.

Therefore, pressure injection molding methods have recently been developed to eliminate these drawbacks and resolutely improve productivity.

In this press molding method, the slip is molded under a pressure of several to 30 kg / cm 2 into the space between two mold parts, that is, the mold cavity. The porous type is filled with a reinforced pressure vessel or case and the base with a porous forming slurry or powder (eg a mixture of epoxy resin and sand) and cured the slurry or powder to be integrated with the reinforced steel container or box. It is made by forming a structure.

According to this structure, it is very difficult to produce a strong pressure-resistant container or reinforcing steel box whose shape is identical to the product or article to be molded. Due to this difficulty, the porous layer has an extremely large thickness.

Excessive thickness of the porous layer results in an increase in elastic compression tension due to slip pressure during press molding, making the corners of the porous layer easy to crack. Moreover, when removing the molded article from the mold, the reaction of the pressing tension causes the porous layer to drive the molded article, thus making it difficult to release or demould. On the other hand, the press molding method has not only a drainage passage for ejecting the water pushed into the porous mold during molding, but also a compressed air passage for injecting air and water through the porous mold to the mold surface when the molded article is removed from the mold. Required. In the case where the mold consists of two upper and lower parts, for example, the upper part of the mold must be emptied during the removal of the molded part from the lower mold part, so that the molded part can be attracted to the upper molded part but not dropped. For this purpose, air passages are also absolutely necessary. These passages should normally be spaced and spaced from the mold surface, which can be shared and will also result in the injection of water and air, thereby not causing problems during demolding. Various methods for forming such water and air passages have been proposed but faced difficulties in their manufacture and use.

According to one of the prior art manufacturing methods, in more detail, a porous mold with water and air passages forms a wire mesh into a cage held at a desired distance from the mold surface, and is a porous tube or tube of coils covered with a cloth. The members are fixed at appropriate intervals, the cage is fixed to the pressure resistant container at the desired interval from the mold surface, the pressure resistant container is bonded to the base case to form a mold cavity, and the mold cavity is made by molding and curing the slurry. This method requires the cage to be formed for each mold, the cage of the wire mesh to have the correct mold, difficulty in arranging the water path in the porous layer accurately, and the difficulty in making the tubular members adhere to the cage. There is a flaw. Since the water and air passages according to this method are difficult to have a small diameter, the void is enlarged at the intersection of the passageway, causing problems with the mold's strength and distance from the mold surface, thus another drawback that the passageway cannot freely cross. Brings about.

According to another proposed method (Japanese Patent Publication No. 8010/1985), the flexible and rigid lines are fixed directly to the reinforcing steel box, which is connected to the substrate to form a mold cavity. Porous layer forming slurry is molded and hardened in the shaped steel. After the slurry has cured, the line is drawn out to form a drain passage. According to this method, however, the iron box cannot be the same shape as the molded product or article. As a result, the passage of moisture and air cannot be formed as desired, with a selected distance from the space from the mold surface.

According to another proposed method, the grooves are formed on the back side of the preformed porous mold by the tool and covered with adhesive tape to form a passage of water and air. This process has the drawback that the dimensional accuracy of the groove is not achieved and the operator's fingers are deciphered by the adhesive because the adhesive tape is attached to the groove manually. Another drawback is that when the mold is used, compressed air leaks from the attachment and the mold breaks.

It is therefore an object of the present invention to provide a manufacturing method of the type which is free from the above drawbacks of the prior art and which is easy to manufacture and suitable for use.

According to a first aspect of the invention, the step of attaching the holding member in a row at a predetermined interval to the upper case made of a hard material so that the holding member protrudes a predetermined distance from the inner surface of the upper case; Removably attaching a flexible line to the retaining member; Passing at least one end of each of the flexible lines through the upper case to an outer axis of the upper case; Injecting a slurry into a mold cavity defined by the upper case and a base connected to the upper case to form a porous layer; Removing the upper case together with the retaining member from the porous mold after the slurry is cured to separate the retaining member from the flexible line so as to leave the flexible line in the porous mold; Filling a hole remaining in the porous mold with a resin at the position where the holding member was; Extracting the flexible line from the porous mold to form a channel (path) in the porous mold after the resin is cured; Provided is a method for producing a porous type consisting of.

According to a second aspect of the invention, the step of attaching the holding member to the upper case by a magnet fixed to the inner surface of the upper case at a predetermined interval; Fixing at least one end of each of the flexible lines to the outside of the upper case to fix the flexible lines to the holding member; Connecting the upper case to a base to form a mold cavity therebetween; Injecting a slurry into the cavity to form a porous form; Removing the top case from the porous mold to leave the retaining member with the flexible line in the cured porous mold after the slurry has cured; Extracting the retaining member from the porous mold to leave a hole; Filling the hole with a resin; Drawing out the flexible line from the porous mold to form a channel after the resin is cured; Provided is a method for producing a porous type consisting of.

According to a third aspect of the invention, there is provided a method, comprising: forming a recess in at least a portion of an inner surface of an upper case made of a hard material; Removably inserting a soft rubber member in the recess in the same plane as the inner surface of the upper case; Attaching the holding members in a row at predetermined intervals to the remaining portions of the inner surface of the soft rubber member and the inner surface of the upper case such that the holding members protrude by a predetermined distance; Removably securing the flexible line to the retaining member by at least one end of the flexible line extending through the upper case to the outside of the upper case; Connecting the upper case to a base to form a mold cavity; Injecting a slurry into the mold cavity to form a porous mold; After the slurry has cured, removing the upper case with its retaining member to leave the soft rubber member on the porous mold; Removing the soft rubber member together with its retaining member from the porous mold to leave a hole in the trace of the retaining member; Filling the hole with a resin; After the resin is cured, extracting the flexible line from the porous mold to form a channel in the porous mold; Provided is a method for producing a porous type consisting of.

According to a fourth aspect of the present invention, the hard line is attached to the upper case at a predetermined interval in a removable manner; Attaching at least one flexible line to the upper case such that the rigid lines intersect and at least one end thereof extends through the upper case to its outside; Connecting the upper case to a base to form a mold cavity; Injecting a slurry into the mold cavity to form a porous mold; Extracting the hard line and the flexible line from the upper case after the slurry is cured; There is provided a method of manufacturing a porous mold comprising the step of removing the upper case from the porous mold to form a channel in the porous mold. Thus, the porous channel prepared by the above-described method is used to drain the filtrate during the injection molding process and to evenly introduce water and air onto the molding surface through the porous mold when the molded product is dismantled from the mold. For example, if the mold consists of upper and lower parts, the molded part cannot be removed from the upper and lower mold parts at the same time. The channel is also used to exhaust the porous layer of the mold. Thus, due to the exhaust, the molded article is drawn into the upper die portion, and the compressed air can be blown out to the lower die portion and dismantled from the molded article. Next, compressed air is supplied to the upper portion so that the molded article can be dismantled or removed from the upper portion.

For this operation, the channels are composed of one or more trunk channels communicating with the outside of the type and a plurality of branch channels intersecting and communicating with the trunk channel at one or more points. Trunk and branch channels are arranged in the mold at the desired distance and from the mold surface. This makes it necessary to close the two ends of each branch passage.

On the other hand, when large and complex shaped parts are to be dismantled, such dismantling can occur locally or inadvertently. Because of this, it is necessary to change the pressure of the compressed air blown out to the local mold for smooth mold removal operation.

If all the channels of the mold communicate as a whole, the amount of water in the form may be biased on one side, adversely affecting the mold's dismantling or locally softening the dismantled part. Because of this, it is necessary to divide the channels in the mold into independent blocks so that the water content in the mold can be controlled. Therefore, according to the present invention, the channels in the porous mold are preferably independent of each other so as not to communicate, but each has an trunk channel for providing communication out of the mold.

Other objects, features and advantages of the invention will be apparent from the description with reference to the accompanying drawings.

The present invention is described in detail below with reference to the accompanying drawings.

1 is a cross-sectional view showing a porous mold produced by the method of the present invention. The porous mold 1 has a plurality of passages formed therein such as a channel 2 for communicating water and air. Channel 2 is schematically composed of intersecting edges 2a and branching channels 2b as shown in FIG.

3 shows the upper case 3 used to produce a generally flat porous form by the method of the present invention. The upper case 3 is made of a hard material such as FRP. A plurality of flexible lines 5 arranged substantially horizontally at predetermined intervals are attached to the upper box 3 by the retaining member 4. Reference numeral 5a denotes a flexible line for the branch channel, which is crossed by the flexible line 5b for the trunk channel. All of these flexible lines 5 have respective ends extending to the outside of the upper case so that these flexible lines can be ejected out of the porous mold 1 after the porous mold 1 has cured. The flexible line 5 is preferably formed into a rod or tube having a circular or oval cross section and is made of an elastic and strong material such as silicone or polyethylene rubber. It is preferable that this line 5 is 1-5 mm in diameter.

As best shown in FIG. 5, the holding member 4 for the flexible line 5 is directly fixed to the upper box 3 in a row at a predetermined interval according to the arrangement of the flexible line 5, It protrudes by the predetermined length from the inner surface of the box 3. Each retaining member 4 is provided with a dent 6 at its line end to removably fix the flexible line 5 as long as the flexible line is pressed when corresponding.

Therefore, as shown in FIG. 4, the upper case 3 having the flexible line 5 is connected to the base 7 to form a mold cavity therebetween, and the slurry 9 is the upper case 3 It is injected from the injection hole 8 of the) and casts a porous mold. After the injected slurry 9 has cured, the upper case 3 is removed to leave the porous mold 1 on the base (as shown in FIG. 6). The retaining member 4 is removed from the flexible line 5 and drawn out together with the upper case 3 to leave the flexible line 5 in the porous mold 1. The hole 11 is formed in the trace of the holding member 4 at the back of the porous die 1 (as shown in FIG. 6). Next, the holes 11 are filled with the resin 12 as shown in FIG. This filling resin 12 is preferably a putty adhesive having low fluidity. After the filling resin 12 is cured, the flexible line 5 is drawn out of the porous mold 1 to leave the channel 2 in the porous mold 1 (as shown in FIG. 8).

The upper case 3 shown in FIG. 3 can be removed from the porous mold without causing the retaining member 4 to be caught in the porous mold. However, in the case where the formed porous mold has a vertical and / or inclined surface in addition to the horizontal plane, the upper case 3 cannot be removed from the porous mold unless the retaining member 4 is removably attached to the upper case 3. .

FIG. 9 shows a state where the flexible line 5 is arranged on the upper case 3 which is suitable for making the porous dies with vertical and inclined planes in addition to the horizontal plane. Similarly to FIG. 3, the flexible line is composed of a flexible channel 5a for branch channels and a cross flexible line 5b for trunk lines. As best shown in FIG. 11, there is a fixed embedding magnet 14 for loosely pulling the retaining member 4 by an iron string 15 embedded in the lower surface of the retaining member 4. Each of these retaining members 4 has a dent 6 formed at its distal end to which the member corresponding to the flexible line 5 is pressed. Therefore, as shown in FIG. 10, the upper case 3 having the flexible line 5 is combined with the base 7, and the slurry 9 forming the porous mold has two cases 3,7. It is injected into the mold hole determined by. After the slurry forming the porous mold is cured, the upper case 3 is stripped from the porous mold 1. Next, the magnet 14 is removed from the holding member to leave the holding member 4 in the porous mold (as shown in FIG. 13). After doing so, the retaining member 4 is removed, leaving a hole 11.

These holes are then filled with resin 12 (as shown in FIG. 14). After this filling resin 12 is cured, the flexible line 5 is extracted to leave a channel in the porous mold 5.

Reference is now made to FIGS. 16-22, which show a variant of the method for producing a porous mold having vertical and inclined surfaces in addition to the horizontal plane.

In this variant, the portions forming the porous vertical and inclined surfaces are made of a soft rubber member 16, which is assembled and disassembled to fit the recesses 17 formed in the upper case 3 so that the case 3 can be assembled. It extends with the inner surface. These assemblings are preferably performed by a magnetic force between the magnet 18 embedded in the inner surface of the recess 17 of the upper case 3 and the iron string 19 embedded in the rear surface of the soft rubber member 16. Can be. The holding member 4 is firmly embedded at a predetermined interval and is arranged on the inner surface of the soft rubber member 16, and the other holding member 4 is also inside the soft rubber member of the inner surface of the horizontal portion of the upper case 3. Sticks parallel to the surface. As in the above embodiment, each retaining member 4 forms a groove 6 at its tip, which is assembled by being fitted with a corresponding one of the flexible lines 5. The soft rubber member 16 is preferably made of, for example, soft urethane rubber.

In the above variant, the soft rubber member is used only in part of the upper case to form vertical and inclined surfaces. However, the upper case can be made of its entire soft rubber and attached by magnet attachment means so that its shape can be held by the rigid support material. Accordingly, as shown in FIG. 16, the rigid upper case 3 supporting the soft rubber member 16 and the flexible line 15 is connected to the base 7 and the porous forming slurry 9 has two cases ( It is injected into the mold cavity between 3 and 7. After the slurry 9 has cured, the upper case 3 is removed (as shown in FIG. 19). The magnet 18 of the upper case 3 is then separated from the built-in steel string 19 of the soft rubber member 16 to leave the soft rubber member 16 around the porous mold 1. At this time, the holding member 4 fixed to the upper case 3 is removed from the porous mold 1 at the same time as the upper case 3 is removed. The soft rubber member 16 is then peeled off from the porous mold 1 (as shown in FIG. 20). A hole 11 is then formed in the porous mold 1 at the trace of the retaining member 4 of the flexible line 5 and then filled with resin 12 (as shown in FIG. 21). After the filling resin 12 has cured, the flexible line 5 is drawn out to form the channel 2 in the porous mold 1 (as shown in FIG. 22).

Figures 23-27 illustrate another embodiment of the present invention wherein rigid lines are used to form branch channels and flexible lines are used to form trunk channels having communication with the outside of the mold.

As shown in FIG. 23, the hard line 20 is made of stainless steel and has a diameter of 1 to 5 mm, preferably 2 to 4 mm. The upper case 3 is formed of insertion holes 21 into which rigid lines 20 are inserted between both side walls thereof. The flexible line 22 is attached to the upper case 3 across the hard line 20 and has its end extending outwards through the upper case 3.

The upper case 3 and the base 7 are connected to each other, and the porous forming slurry 9 is injected into the mold cavity therebetween (as shown in FIG. 24). In addition, the hard line 20 and the flexible line 22 are discharged from the porous mold 1 and the upper case 3 after the slurry is cured (as shown in FIG. 25). The upper case 3 is then removed from the porous mold 1. Thus, as shown in FIG. 27, the porous mold 1 formed by crossing the trunk and branch channels 2a and 2b can be achieved. In order to ensure communication at the intersection between the trunk channel 2a and the branch channel 2b, the hard line 20 and the flexible line 22 may be preferably connected at the intersection by the ring 23. (As shown in FIG. 26).

28 is a perspective view showing the porous mold 1. In the state shown, the flexible line is filled with resin 12 on the opposite surface 25 of the porous mold 1 facing the mold surface 24 so as to communicate with the outside. The leading ends of the provided trunk channel 2a and branch channel 2b are closed with resin 26 on the sides of the porous die.

29 is a cross section showing the rectangular porous die 1. In this illustrated state, the lower part 27 and the side parts 28a and 28b have channels made independently of each other so that there is no communication. Reference numerals 25, 2a and 2b denote the molding surface, trunk channel and branch channel of the mold, respectively. Reference numeral 29 denotes a pipe part for providing communication between the trunk channel 2a and the outside of the type.

As described above, according to the present invention, when the porous mold for pressure injection molding is manufactured, an upper case having a line for forming a channel for the communication of water and air in the porous mold is used so that the molding surface from the mold to the channel is used. The spacing and the diameter of the space and the channel can be precisely adjusted to practically eliminate the disadvantages associated with the known art. In addition, the wires can be attached to the upper case in a predetermined arrangement very quickly and simply without skilled technology, so that the operation efficiency can be firmly improved.

Claims (5)

Forming a recess 17 on at least a portion of an inner surface of the upper case 3 of a hard material; Removably fixing the soft rubber member (16) in the recess (17) in the same plane as the inner surface of the upper case (3); Attaching the holding member (4) in a row at predetermined intervals to an inner surface of the soft rubber member (16) and a remaining portion of the inner surface of the upper case (3) such that the holding member (4) protrudes by a predetermined distance; At least one end of the flexible line (5) extends through the upper case (3) to the outside of the upper case (3) to removably fix the flexible line (5) to the holding member (4); Connecting the upper case 3 to the base 7 to form a mold cavity; Injecting a slurry into the mold cavity to form a porous mold (1); After the slurry 9 is cured, removing the upper case 3 together with its retaining member 4 to leave the soft rubber member 16 on the porous die 1, the retaining member. Removing the soft rubber member (16) together with its retaining member (4) from the porous mold (1) to leave a hole (11) in the trace of (4); Filling the hole (11); After the resin (12) is cured, extracting the flexible line (5) from the porous mold (1) to form a channel (2) in the porous mold (1); Method for producing a porous type, characterized in that. The method of claim 1, wherein the soft rubber member (16) is made of soft urethane rubber. The method according to claim 1, wherein the soft rubber member (16) is injected into the case (3) supported by the rigid support member through the magnet means (18). 2. The channel (2) according to claim 1, wherein the channel (2) is at least one trunk channel (2a) which provides communication between the interior and exterior of the porous die (1), intersects with, and communicates with, the closed channel (2a) and is closed. A porous type manufacturing method characterized by comprising a plurality of branch channels (2b) having an open end. 5. A method according to claim 4, wherein the channels (2b) are independent of each other and there is no communication between them but each communicates with the trunk channel (2a).

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