JPH04303602A - Mold and method for sludge casting - Google Patents

Abstract

PURPOSE:To form an exact hole part at the predetermined positions of ceramic port liner and the like, ensure favorable releasability, at the same time, make it possible to continuously mold under the condition that excellent durability is maintained. CONSTITUTION:In order to obtain a ceramic compact 5 having a hole part 7, drain casting molds 1 and 1' having a water non-permeable projection part 3, which is exposed at the position corresponding to the hole part 7 of a forming mold surface 8, are used. When ceramic slurry is cast in the interior of the sludge casting molds 1 and 1', water is absorbed in the forming mold surface 8 of the sludge casting molds 1 and 1', resulting in proceeding the casting, the proceeding of the casting is performed under the condition that slurry is replenished by the amount of the slurry reduced by the absorption of water. When the predetermined thickness of the casting is obtained, slurry is discharged. In this case, since the water non-permeable projected part 3 has no water absorbing action by the sludge casting molds 1 and 1', no casting develops at the part 3, resulting in forming the hole part 7 of the ceramic compact 5.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a mold for removing mud and a casting method for removing mud. The present invention relates to a sludge casting mold and a sludge casting molding method using the same.

0002

[Prior Art] The slurry casting method is a method in which ceramic slurry is poured into a water-absorbing mold such as a plaster mold, and after it is deposited on the inner surface of the mold, the excess slurry is discharged. However, when molding products with holes, conventionally the holes were formed by machining using a drill or the like after molding or firing, but this had operational difficulties such as easy cracking. . Furthermore, when the processed surface has a three-dimensional curved surface, processing takes time, positioning is difficult, and accurate processing requires a large number of man-hours.

[0003] Therefore, the present applicant filed an earlier application (Japanese Unexamined Patent Publication No.
-99805), by applying any means such as attaching a water-impermeable seal to the position corresponding to the valve hole on the inner surface of the ceramic port liner drainage casting mold or embedding resin. proposed a method using a water-absorbing mold with a water-impermeable surface shaped to correspond to the valve hole. By using this mold, it is possible to pour ceramic slurry inside the mold, deposit it to the required thickness on the portions excluding the water-impermeable surface, and obtain a ceramic port liner with holes in the valve hole portions.

0004

[Problems to be Solved by the Invention] However, the method proposed by the present applicant in Japanese Patent Laid-Open No. 1-99805 is a method for accurately and easily manufacturing holes using simple means, but it is difficult to manufacture holes after several uses. A thin film is likely to form on a water-impermeable seal, etc., and if continuous molding is performed, it may become impossible to form complete holes, so there is room for improvement in this point.

[0005]

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to completely form holes even after continuous molding is performed several dozen times or more. An object of the present invention is to provide a sludge casting mold and a sludge casting method capable of forming a sludge casting mold. That is, according to the present invention, a mud draining casting is provided in which a convex portion made of a water-impermeable material and having a height of preferably 10% to 110% with respect to the wall thickness of the molded body is provided on a part of the molding surface. A mold for pouring and a method for draining mud casting, which is characterized in that a molded article having holes is obtained using the same, are provided. Further, in the present invention, the height of the convex portion is 25% to 90% of the wall thickness of the molded body,
It is further preferable to make the height of the convex portion lower than the thickness of the deposited portion.

[0006]

[Operation] In the present invention, in order to obtain the ceramic molded body 5 having the holes 7 as shown in FIGS. 6 to 9, for example, as shown in FIG. Mud removal casting molds 1 and 1' having convex portions 3 made of water-impermeable material exposed at corresponding positions are used.

When the ceramic slurry is poured into the molds 1 and 1', the ceramic slurry absorbs water and adheres to the molding surfaces 8 of the molds 1 and 1', which are water-absorbing. As the thickness progresses, the slurry is replenished by the amount of slurry that has been reduced due to water absorption in the slurry casting molds 1 and 1', and when a predetermined thickness is reached, the slurry is discharged. In this case, the portion of the impermeable convex portion 3 is
, 1', there is no water absorption effect, so no inking is performed and the required holes 7 of the ceramic molded body 5 are formed. Note that 9 indicates a hole for pouring and draining mud, and 10 indicates a hole for pressurized air. In this case, the most important thing is the ratio of the height of the water-impermeable convex portion 3 to the thickness of the ceramic molded body 5. If it is too low, repeated molding during hole molding will result in incomplete hole molding, and if it is too high, mold releasability will deteriorate.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to illustrated examples, but the present invention is not limited to the illustrated examples. The following example mainly describes the molded product shown in FIG. 6, but by changing the molding surface of the mold, a head port liner (see FIG. 7), a head plate (see FIG. 8), and a sub It can be applied to products having holes such as a combustion chamber (see FIG. 9) and an exhaust manifold liner.

FIG. 1 is an explanatory cross-sectional view showing the overall structure of the mold for discharging mud casting used in the implementation of the present invention, and FIG. 2 is an explanatory cross-sectional view showing an enlarged main part of the mold for discharging mud casting shown in FIG. It is a diagram. In the figure,
1 and 1' indicate molds for mud removal casting, and mold 1 for molding
A convex portion 3 formed by embedding a placing core 2 made of a water-impermeable material in a mold 1 is exposed on a part of the molding surface 8 . As the sludge casting molds 1 and 1', a water-absorbing resin mold can be used in addition to a plaster mold.

[0010] As the placing core 2 forming the convex portion 3, any type of material can be used as long as it is water-impermeable, and metals such as stainless steel, water-impermeable materials such as plastic may be used. However, it is preferable to use a fluororesin such as polytetrafluoroethylene such as Teflon (manufactured by DuPont), which is difficult to wet with the ceramic slurry.

[0011] Further, the side surface 11 of the convex portion 3 is preferably tapered (angle θ) or curved in consideration of the direction and releasability of the mold from the sludge casting mold 1. It is also preferable to have the tip of the protrusion 3 beveled as shown in FIG. 3, and to form the tip of the protrusion 3 into a spherical shape of about 0.5 to 2R as shown in FIG. Sludge casting mold 1
It is preferable that the portion of the placing core 2 embedded therein be made as small as possible so as not to impede movement of slurry moisture and air blowing during mold release. In addition, in order to prevent the placing core 2 from falling off or rotating, the annular groove 4 is
Alternatively, it is preferable to provide a threaded groove, or it is also preferable to cut a male thread into the side surface of the placing core 2.

Furthermore, it is preferable that the side surface 11 of the convex portion 3 be finished smooth and have a surface roughness of 25S or less from the viewpoint of ease of removal. In addition, as a method for embedding the placing core 2 in the mold 1 for mud removal casting, the raw material for the mud removal casting mold is poured into a mold for making a mold for mud removal casting in a liquid state. In this case, when making the mold for mud removal casting, the placing core 2 having the annular groove 4 should be placed so that the part protruding from the mud removal mold is hidden in the mold for making the mud removal mold. It is possible to adopt a method in which the part to be set and embedded in the sludge casting mold is wrapped with the raw material of the sludge casting mold. It is also possible to form a female thread in the mold 1, or to screw the female thread into a mold that directly wraps around the mold 1 and is provided with a screw.

[0013] More specific implementation results will be explained below. (Example) As slurry, Al2O3 56%,
For a mixture of 41% TiO2 and 3% SiO2,
A mixture of 0.5% deflocculant, 3% binder, and 22% water (all by weight) was used. A resin with an average pore diameter of 30 μm is used as the structural material of the mold 1 for mud removal casting, and as shown in Figs. The cross section of the molded body 5 has a long (horizontal) diameter of 100 mm and a short (vertical) diameter of 30 mm.
One that forms an ellipse of mm was adopted. The placing core 2 to be embedded in the sludge casting mold 1 was formed from a cylindrical body with a diameter of 12 mmφ and a height of 6 mm, and a truncated cone with a bottom surface of 12 mmφ and a base angle of 60°. An annular groove 4 for preventing falling off was provided on the side surface of the cylindrical body, and the cylindrical body portion was mainly embedded inside the mold 1 for mud removal casting molding.

[0014] The slurry obtained above was poured into the sludge casting molds 1, 1' and pressurized at a pressure of 30 kg/cm2 for 50 seconds. Next, in order to eliminate excess slurry and reduce the moisture content of the inked ceramic molded body 5, 6 kg/cm was added to the ceramic molded body 5 from inside the molded body.
Pressure was applied for 1 minute with air from Step 2. Then, the ceramic molded body 5 was taken out by air blowing from the back hole 6 provided in the mud removal casting molds 1, 1'. The ceramic molded body 5 taken out was air-dried overnight, and the presence or absence of cracks was visually confirmed. Table 1 shows the relationship between the molding state of the hole and the mold releasability with respect to the convex state of the convex part 3 of the placing core 2 (ratio of the protrusion height h of the convex part 3 to the thickness t of the ceramic molded body 5).

[0015]

[Table 1]

As is clear from the results in Table 1, the protrusion height h of the convex portion 3 is expressed as h/with respect to the thickness t of the ceramic compact 5.
It can be seen that the molding condition and mold releasability are excellent by using the mud removal casting mold formed so that t is in the range of 10/100 to 110/100. Next, the taper angle θ of the convex portion 3 was changed to measure the relationship between the molded state of the hole and the mold releasability. The results are shown in Table 2.

[0017]

[Table 2]

From the results in Table 2, it can be seen that the taper angle θ of the convex portion 3 is preferably 5 to 75°.

[0019]

[Effects of the Invention] As explained above, according to the present invention,
Since molding is performed using a mud-removing casting mold that has a water-impermeable convex portion of a predetermined height relative to the wall thickness of the molded body, holes can be formed accurately at predetermined positions, and the molded body can be formed with good quality. Mold releasability can be ensured. In addition, even during continuous molding, molding with excellent durability can be achieved.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view showing the overall structure of a sludge casting mold used in the implementation of the present invention.

FIG. 2 is an explanatory cross-sectional view showing an enlarged main part of the sludge casting mold shown in FIG. 1;

FIG. 3 is an explanatory cross-sectional view showing an enlarged main part of the sludge casting mold shown in FIG. 1;

FIG. 4 is an explanatory cross-sectional view showing an enlarged main part of the sludge casting mold shown in FIG. 1;

5 is a perspective view of the sludge casting mold shown in FIG. 1 in an open state; FIG.

FIG. 6 is a perspective view of a ceramic molded body obtained by implementing the present invention.

FIG. 7 is a perspective view of a head port liner obtained by implementing the present invention.

FIG. 8 is a perspective view of a head plate obtained by implementing the present invention.

FIG. 9 is a perspective view of a sub-combustion chamber obtained by implementing the present invention.

[Explanation of symbols]

1,1'　　Mold for sludge casting molding 2 Placement core 3 Convex part 4 Annular groove 5 Ceramic molded body 6　Back hole of mud removal molding mold 7 Hole 8 Molding surface of sludge casting mold 9 Sludge pouring and draining hole 10 Pressurized air hole 11　Side surface of the convex part of the placing core

Claims (2)

[Claims] 1. A mud-removing mold for casting, characterized in that a convex portion made of a water-impermeable material is provided on a part of the molding surface. 2. A method for casting and molding a sludge-removing material, characterized in that the mold according to claim 1 is used to obtain a molded article having holes.