JP2003251659A - Method for manufacturing porous body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a porous body by which the porous body through which a plurality of fine holes pass mutually in parallel can be highly accurately manufactured without after-processing and in particular, the heavy plate-like porous body in which a large number of fine holes are highly densely arranged can be highly accurately manufactured, too. <P>SOLUTION: Apex parts of a group 10 of molding pins are pushed into a molding material while a pressure is applied on the molding material R filled in a cavity C and under a plasticized condition by a core 4. In this instance, the core 4 is moved in the direction separated from a fixed mold 2 through the molding material under a plasticized condition in the cavity C in accordance with amount of pushing-in of the group 10 of the molding pins. After the apex parts of the group 10 of the molding pins are brought into contact with a cavity face C2, the molding material R is solidified while the pressure is applied on the molding material in the cavity by the core 4. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a porous body in which a plurality of pores penetrate parallel to each other by post molding without any post-processing. The present invention relates to a production method suitable for producing a porous body in which a large number of pores are arranged at high density. 2. Description of the Related Art Molded products in which a plurality of pores penetrate each other in parallel (hereinafter referred to as “porous body”) have been widely used for collimators, filters and the like. When this type of porous body is molded by injection molding, if the diameter of the plurality of molding pins for molding the pores is as small as about 0.5 to 1 mm, the filling pressure of the molding material and the molding material solidify. Due to the contraction force at the time of deformation, deformation such as collapse or bending may occur in each molding pin. This is because the pressure distribution of the molding material in the cavity is not uniform. Further, when molding a porous body in which a large number of pores are arranged at a high density at a narrow interval, a large number of molding pins must be arranged at a narrow interval in the cavity. If the distance between the pins is narrow, it is difficult for the molding material to enter between them, and therefore there is a possibility that the molding material will be insufficiently filled between the molding pins. As described above, when deformation such as collapse or bending occurs in each molding pin, or when insufficient filling of the molding material occurs between the molding pins, it is natural that the plurality of pores molded into the porous body are formed. There is a problem that collapse or bending occurs, or a part of the partition walls between adjacent pores is lost, resulting in frequent occurrence of defective products. In order to solve such a problem, Japanese Patent Application Laid-Open No. 4-261802 discloses a core pin for molding pores in a molding body molding space (cavity), both ends of which move with a fixed mold. A slide insert that is fixedly supported by the mold and that concentrically holds the core pin is movably arranged, and when the molding material is injected into the cavity, the core pin is inserted with the slide insert. While holding
The slide insert is retracted by the filling pressure of the molding material,
A method for forming a molded body having pores is disclosed.
In this prior art, when a molding material is injected into a cavity, the core pin is held by a slide insert so as to prevent the core pin from being deformed by a filling pressure of the molding material. In this prior art, the slide material is retracted by the filling pressure of the molding material so that the molding material can be filled into the cavity with a uniform density. Japanese Patent Laid-Open No. 7-241881 discloses that a porous body is formed by inserting a group of molding pins composed of a plurality of pins into a molding material while the molding material injected into the cavity is in a plastic state. A method of forming is disclosed. In this publication, when inserting the tip of the molding pin group into the molding material, the movable mold wall is moved so that the molding space (cavity) is equivalent to the volume of the molding pin group inserted into the molding material. Only a method of enlarging is disclosed. This prior art is intended to solve the lack of flow of molding material in the vicinity of each molding pin by inserting a group of molding pins into a molding material in a plastic state. In addition, when inserting the molding pin group into the molding material, it is possible to prevent damage to the pin due to the pressure rise in the cavity by enlarging the cavity by an amount corresponding to the volume of the molding pin group inserted into the molding material. Yes. Further, Japanese Patent Application Laid-Open No. 11-216885 discloses an introduction guide portion provided so as to seal all the outlets of one of the through holes (pores of the molded body), a molding pin for molding the through holes, and A method is disclosed in which a molding material is used, a molding material is injected into the die in a direction parallel to the axis of the molding pin, and an introduction guide portion of the resulting molded body is removed after molding. In this prior art, a molding material introduction guide portion is provided in a molding die, and a molding material gate is provided in the introduction guide portion, so that the flow of the molding material in a direction perpendicular to the axis of the molding pin is parallel. The flow can be changed to flow in the direction, and the gap between adjacent molding pins can be filled uniformly and sufficiently with a good flowability of the molding material. However, in the method disclosed in Japanese Patent Laid-Open No. 4-261802, the core pin is fixedly supported in the cavity between the fixed mold and the movable mold. Therefore, there is a problem that the structure of the molding die becomes complicated. In this method, when the thickness of the molded product is small, it is difficult to arrange the gate for injecting the molding material in the axial direction of the molding pin because of the structure of the molding die. It is filled from a direction other than the axial direction. Therefore, there is a problem that the molding pin falls or bends due to the filling pressure of the molding material. Furthermore, in this prior art, only the case of molding a molded body having one pore is mentioned, but when this method is applied to a molded body having a large number of pores, the molding material is arranged in a row of pins. Therefore, if the space between the molding pins is narrow, the molding material is difficult to enter, and the molding material is insufficiently filled between the molding pins. Further, in the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-241881, it is said that the lack of flow of the molding material in the vicinity of each molding pin can be solved, but if the space between the molding pins is narrow, The problem that the molding material is difficult to enter and the molding material is insufficiently filled between the molding pins has not been solved. In addition, when inserting a molding pin group into a molding material, it is possible to prevent damage to the pin due to an increase in pressure in the cavity by enlarging the cavity by an amount corresponding to the volume of the molding pin group inserted into the molding material. However, since the cavity is enlarged by the volume corresponding to the volume of the molding pin group to be inserted into the molding material, when the tip of the molding pin group is inserted into the molding material in the plastic state, the molding in the plastic state is accordingly performed. There is a tendency for the material to flow around the molding pin group without entering between the molding pins.
As a result, a filling failure of the molding material may occur between the molding pins, or the molding pins may fall down or bend due to the flow pressure of the molding material. Furthermore, the above-mentioned Japanese Patent Laid-Open No. 11-21688.
In the method disclosed in No. 5 publication, the flow of the molding material can be changed to a flow in a direction parallel to the molding pin, and the molding material can be uniformly placed in a state of good fluidity in the gap between the adjacent molding pins, and However, the problem that the molding material is difficult to enter when the space between the molding pins is narrow and the molding material is insufficiently filled between the molding pins has not been solved. In addition, since the molding material easily enters the portion without the molding pin than between the molding pins, the molding material is filled in the cavity first from the portion without the molding pin. For this reason, the pressure distribution of the molding material filled in the cavity is not uniform, and there is a problem that deformation such as collapse or bending occurs in the molding pin due to the difference in the pressure distribution. There is a difficulty in forming a porous body in which a large number of pores are arranged at high density with high accuracy. That is, in the prior art of each of the above publications, when a porous body is injection molded using a group of molding pins in which elongated molding pins are arranged at high density, each molding pin is deformed such as falling or bending. And there is a problem of insufficient filling of the molding material between the molding pins.
There is a difficulty in forming a porous body in which a large number of pores are arranged at high density with high accuracy. Therefore, according to the present invention, a porous body having a plurality of pores penetrating in parallel with each other can be manufactured with high accuracy without post-processing, and in particular, a large number of pores are arranged with high density. It is an object of the present invention to provide a method for producing a porous body capable of producing a thick plate-like porous body with high accuracy. As a means for solving the above-mentioned problems, a method for manufacturing a porous body according to the present invention is to manufacture a porous body in which a plurality of pores penetrate parallel to each other by injection molding. In doing so, the tip and the movable mold that form a cavity corresponding to the porous body and the fixed mold or the movable mold are slidably penetrated to advance the tip portion into the cavity. Using a mold apparatus having a group of molding pins parallel to each other whose tip is in contact with the cavity surface, first, the tip of the molding pin group is melted into the cavity while being retracted from the cavity. The molding material in a state is filled, and then the tip of the molding pin group is advanced into the cavity and pressed into the molding material while applying pressure to the plastic molding material in the cavity with the moving mold. In this case, the moving mold is moved away from the fixed mold through the plastic molding material in the cavity according to the pushing amount of the molding pin group, and the tip of the molding pin group is After contacting the cavity surface, the molding material is solidified by maintaining a state where pressure is applied to the molding material in the cavity by the moving mold. In the method for producing a porous body according to the present invention, the molten molding material is filled into the cavity in a state in which the tip of the molding pin group is retracted from the cavity.
Each molding pin can be prevented from falling or bending due to the flow of the molding material. And in order to push the tip of the molding pin group into the molding material while applying pressure to the plastic molding material filled in the cavity, the plastic molding material flows along the axial direction of each molding pin, Each molding pin is securely filled around each molding pin without causing the molding pin to fall or bend. At that time, since the moving mold is moved in the direction away from the fixed mold through the molding material in the plastic state in the cavity according to the pushing amount of the molding pin group, an increase in pressure of the molding material in the cavity is avoided, Breakage of each forming pin is prevented. As a result, the respective molding pins of the molding pin group are reliably pushed into the molding material while maintaining a state parallel to each other without causing collapse or bending until the tips thereof come into contact with the cavity surface. And since the molding material is solidified while maintaining the pressure applied to the molding material, sink marks of the molded porous body are prevented. Therefore, in the manufactured porous body, a plurality of pores parallel to each other are formed as through holes with high accuracy. In the method for producing a porous body of the present invention, the “state where the tip of the molding pin group is retracted from the cavity” means only the state where the tip of the molding pin group is completely retracted from the cavity. In addition, a substantially retracted state is also included. In other words, the tip of the molding pin group does not substantially affect the flow of the molding material filled in the cavity, and the tip of the molding pin group does not fall or bend unless the molding material flows under pressure or bending. It may be slightly protruding. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for producing a porous body according to the present invention will be described below with reference to the drawings. In the drawings to be referred to, FIG. 1 is a cross-sectional view of a mold apparatus used in a method for manufacturing a porous body according to an embodiment, and FIG. 2 is an enlarged cross-sectional view of the vicinity of a core shown in FIG. A porous body manufacturing method according to one embodiment uses a mold apparatus 1 as shown in FIGS.
This is a method for producing a porous body M as shown in FIG. 7 by injection molding through the steps shown in FIG. there,
First, the structure of the mold apparatus 1 will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the mold apparatus 1 includes a fixed mold 2 and a movable mold 3. The movable mold 3 includes the fixed mold 2 as shown in FIG. 2 is a cavity C which is a molding space for the porous body M (see FIG. 7).
The core 4 which forms is assembled. The core 4 has a plurality of pores H in the porous body M (see FIG. 7).
Is formed so as to be slidably penetrated so that the tip portion thereof can advance into the cavity C. As shown in FIG. 1, the fixed mold 2 is composed of an upper plate portion 2A and a lower plate portion 2B installed on the lower surface of the upper plate portion 2A. In the upper plate portion 2A,
A runner 12 into which the molten molding material flows and a gate 13 for injecting the molten molding material from the runner 12 into the cavity C (see FIG. 2) are formed. Correspondingly, a sprue bush 14 for supplying a molten molding material to the runner 12 from an injection device (not shown) is mounted on the fixed side mounting plate 5. On the other hand, the lower plate portion 2B is formed of the porous body M.
It is configured so that it can be separated from the upper plate portion 2A when the mold is opened after molding (see FIG. 7). As shown in FIG. 2, the lower plate portion 2B is formed with a cavity hole C1 in which a small diameter portion 4A at the tip of the core 4 formed in a stepped cap shape is slidably fitted. The cavity C is formed by the wall surface of the cavity hole C1, the cavity surface C2 where the gate 13 of the upper plate portion 2A opens, and the cavity surface C3 of the upper end surface of the small diameter portion 4A of the core 4. The moving mold 3 includes a large diameter portion 4 of the core 4.
The upper plate portion 3A that fits B and the lower plate portion 3B that supports the lower surface of the large-diameter portion 4B of the core 4 by being joined to the lower surface of the upper plate portion 3A. Large diameter part 4 between
The core 4 is assembled by sandwiching B. This moving mold 3
As shown in FIG. 1, it is supported on the moving side mounting plate 8 via a plurality of hydraulic cylinders 6 and their receiving plates 7. The hydraulic cylinder 6 is, for example, a double-acting hydraulic cylinder, and expands and contracts in response to a switching operation of an electromagnetic switching valve of a hydraulic circuit (not shown), and the moving mold 3 is fixed to the fixed mold 2 by the extending operation. The moving mold 3 is moved backward in a direction away from the fixed mold 2 by the contraction operation. This hydraulic cylinder 6
The operating pressure at the time of expansion is controlled so as to operate at the set pressure by a relief valve provided in the hydraulic circuit, and the stroke changes so as to maintain a predetermined pressure. As shown in FIG. 2, a cylindrical pin holder 9 holding the molding pin group 10 is slidably fitted to the portion of the movable die 3 where the core 4 is assembled. Yes. The upper end portion of the pin holder 9 faces the inside of the large diameter portion 4B of the core 4, and the upper end surface of the pin holder 9 penetrates the small diameter portion 4A of the core 4 and comes into contact with the cavity surface C2 of the fixed mold 2. A plurality of possible guide pins 11 are projected. Moreover, the lower end part of the pin holder 9 is supported on the said movement side attachment board 8 via the hydraulic cylinder 15 shown in FIG. The molding pin group 10 shown in FIG. 2 includes, for example, about 1000 molding pins 10A having a diameter of about 0.5 mm,
Each pin 10A is arranged in a staggered pattern at a high density and protrudes from the upper end surface of the pin holder 9.
Projecting in parallel with each other at extremely narrow intervals of about 0.2 mm, the projecting lengths are aligned. Then, each molding pin 10A of this molding pin group 10 penetrates through the small diameter portion 4A of the core 4 and advances into the cavity C from the cavity surface C3 of the upper end surface thereof, and the cavity surface C of the fixed mold 2
2 is configured to be able to abut. The hydraulic cylinder 15 shown in FIG. 1 is, for example, a double-acting hydraulic cylinder, which expands and contracts in response to a switching operation of an electromagnetic switching valve of a hydraulic circuit (not shown), and is extended via the pin holder 9 by the expansion operation. Each molding pin 10A of the molding pin group 10 is advanced into the cavity C, and each molding pin 10A is retracted from the cavity C through the pin holder 9 by the contraction operation. In the porous body manufacturing method of the embodiment using the mold apparatus 1 configured as described above, first, as a preparation step, as shown in FIG. The mold 3 is moved forward to the fixed mold 2 side, and the cavity surface C2 of the fixed mold 2 and the cavity surface C of the core 4 are moved.
3 to form a cavity C. The cavity C in this case has a volume corresponding to the amount of molding material necessary for molding the porous body M shown in FIG. Further, by retracting the hydraulic cylinder 15, the tip end of each molding pin 10 </ b> A of the molding pin group 10 is retracted from the cavity C through the pin holder 9. In this case, each forming pin 10
The tip of A is usually retracted to a position that is substantially flush with the cavity surface C3 of the core 4, but does not substantially affect the flow of the molding material filled in the cavity C, and As long as the material does not collapse or bend due to the flow pressure of the molding material, it may protrude slightly into the cavity C. Next, as a filling step of the molding material, as shown in FIG. 4, the cavities C with the tips of the molding pins 10A of the molding pin group 10 retracted from the cavities C are formed.
The molding material R is filled inside. That is, a molten molding material R is supplied to the runner 12 from the injection device (not shown) via the sprue bushing 14, and the molding material R is injected from the gate 13 into the cavity C and filled. Examples of the molding material R to be filled include polystyrene resin. Subsequently, as a step of pushing the forming pin group,
As shown in FIG. 5, the tip of each molding pin 10 </ b> A of the molding pin group 10 is advanced into the cavity C while applying pressure to the plastic molding material R filled in the cavity C with the moving mold 3. Push into molding material R. That is, the hydraulic cylinder 6 is extended to move the moving mold 3 forward to the fixed mold 2 side, and pressure is applied to the plastic molding material R in the cavity C at the cavity surface C3 of the upper end surface of the core 4. Then, by extending the hydraulic cylinder 15, the tip of each molding pin 10 </ b> A of the molding pin group 10 is advanced into the cavity C via the pin holder 9, and this is pushed into the molding material R in the plastic state. At this time, since a plurality of guide pins 11 projecting from the pin holder 9 guide the movement of the pin holder 9 by passing through the small diameter portion 4A of the core 4, an unreasonable force such as a twist acts on each molding pin 10A. Instead, the molding pins 10A are pushed into the molding material R while maintaining a state parallel to each other. At this time, the movable mold 3 is moved backward in the direction away from the fixed mold 2 through the pressure of the molding material R in the plastic state in the cavity C according to the pressing amount of the molding pin group 10. That is, when the molding pin group 10 is pushed into the molding material R in the cavity C, the apparent volume of the molding material R increases by an amount corresponding to the pushed volume. The core 4 is moved backward by the pressure of the molding material R in the cavity C against the pressing force of the hydraulic cylinder 6 so as to avoid the pressure increase of the molding material R by expanding the volume of C. Here, the hydraulic cylinder 6 is controlled so that the operating pressure at the time of extension becomes the set pressure by a relief valve of a hydraulic circuit (not shown). For this reason, the hydraulic cylinder 6 slightly contracts so as to absorb the backward movement of the core 4 while maintaining a state where a predetermined pressure is applied to the molding material R in the cavity C via the core 4. In this way, each molding pin group 10 is molded while applying a pressure to the molding material R in a plastic state filled in the cavity C, and while maintaining a predetermined pressure while avoiding an increase in the pressure. Since the tip of the pin 10A is pushed into the plastic molding material R, each molding pin 10A is prevented from being damaged, and the plastic molding material R flows along the axial direction of each molding pin 10A. Each molding pin 10A does not fall down or bend. For this reason,
Each molding pin 10A of the molding pin group 10 is securely held in the molding material R without being tilted or bent until the tip of the molding pin 10A comes into contact with the cavity surface C2 of the fixed mold 2. Pushed in. As a result, the molding material R in a plastic state is reliably filled around the molding pins 10A without a gap. Therefore, while the predetermined pressure is being applied to the molding material R in the cavity C through the core 4 on the movable mold 3 side by the hydraulic cylinder 6, the pressurized state is maintained and the molding material R is solidified. Let For example, the molding material R is solidified by circulating a cooling medium such as cooling water in the fixed mold 2 around the cavity C. Thus, since the molding material R is solidified while being held in a pressurized state, the porous body M to be molded
Sinking (see FIG. 7) is prevented. After the molding material R in the cavity C is solidified, the porous body M molded in the cavity C is released from the cavity C as shown in FIG. That is, after the upper plate portion 2A and the lower plate portion 2B of the fixed mold 2 are separated, the core 4 is moved forward together with the moving mold 3 by the hydraulic cylinder 6, and the cavity surface C3 on the tip surface of the core 4 is porous. The body M protrudes from the cavity C and is released. Then, a portion connected to the gate 13 of the porous body M released from the cavity C is cut. Through these steps, FIG.
As shown in FIG. 4, a thick plate-like porous body M having a plurality of pores H penetrating in parallel with each other is molded to require post-processing. The porous body M has, for example, a thickness of about 5 mm and a diameter of 0.
About 1000 pores H of about 5 mm are densely arranged in a staggered pattern and penetrated in the thickness direction, and the interval between the pores H is an extremely narrow interval of about 0.2 mm. Yes.
This porous body M is excellent in the straightness and parallelism of each pore H. For example, when light parallel to each pore H is irradiated from one side of the porous body M and received on the other side, the amount of incident light The ratio R (= O / I) of the emitted light quantity O to I is at least 0.8.
That's it. Thus, according to the method for manufacturing a porous body of one embodiment, the diameter is small and the length is 1 as compared with the diameter.
High precision with excellent straightness and parallelism of each pore can be produced without post-processing a porous body through which a large number of pores more than 0 times are arranged in parallel with each other at high density. The porous body can be manufactured. Although one embodiment of the method for producing a porous body according to the present invention has been described above, the present invention is not limited to one embodiment, and can be implemented with appropriate modifications. For example, in the mold apparatus 1 used in the manufacturing method of the embodiment, the gate 13 is opened in the cavity surface C2 of the upper plate portion 2A of the fixed mold 2, but the gate is the lower plate portion 2B.
The cavity hole C1 may be opened. In the mold apparatus 1, the core 4
The molding pin group 10 is disposed so as to slidably pass through, but the molding pin group is disposed so as to slidably penetrate the fixed mold 2 and contact the cavity surface C3 of the core 4. May be. Further, as the hydraulic cylinder 6 that moves the core 4 together with the moving mold 3, a double-acting type that is hydraulically driven in the extending direction and the contracting direction is adopted. This hydraulic cylinder 6 is driven hydraulically in the extending direction. In addition, a single-acting type that returns with a spring force in the contraction direction may be employed. As described above, in the method for manufacturing a porous body according to the present invention, the molten pin is molded in the cavity with the tip of the molding pin group retracted from the cavity. Since the material is filled, each molding pin is prevented from falling or bending due to the flow of the molding material. Then, the tip of the molding pin group is pushed into the molding material while applying the pressure necessary to cause the molding material between the molding pins to flow in the axial direction of the molding pin with respect to the plastic molding material filled in the cavity. Therefore, the molding material in the plastic state flows along the axial direction of each molding pin and is reliably filled around each molding pin without causing the molding pin to fall down or bend. At that time, in order to move the moving mold away from the fixed mold through the plastic molding material in the cavity according to the amount of pressing of the molding pin group, an increase in pressure of the molding material in the cavity is avoided, Breakage of each forming pin is prevented. As a result, each molding pin of the molding pin group is
Until the tip abuts against the cavity surface, they are held in parallel with each other without being tilted or bent, and are surely pushed into the molding material. And since the molding material is solidified while maintaining the pressure applied to the molding material, sink marks of the molded porous body are prevented. Therefore, according to the method for producing a porous body according to the present invention, a porous body in which a plurality of pores penetrate parallel to each other can be produced with high accuracy without post-processing.
A thick plate-like porous body in which a large number of pores are arranged at high density can also be produced with high accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a mold apparatus used in a method for producing a porous body according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the vicinity of a core shown in FIG. FIG. 3 is a cross-sectional view of a mold apparatus showing a preparation step of a method for manufacturing a porous body according to an embodiment. FIG. 4 is a cross-sectional view of a mold apparatus showing a filling step of a molding material in a method for producing a porous body according to an embodiment. FIG. 5 is a cross-sectional view of a mold apparatus showing a pressing step of a forming pin group and a solidifying step of a molding material in a porous body manufacturing method according to an embodiment. FIG. 6 is a cross-sectional view of a mold apparatus showing a porous body release step of the porous body manufacturing method according to an embodiment. 7 is a perspective view of a porous body injection molded by the mold apparatus shown in FIG. 1. FIG. [Explanation of Symbols] 1: Mold device 2: Fixed mold 2A: Upper plate portion 2B: Lower plate portion 3: Moving mold 3A: Upper plate portion 3B: Lower plate portion 4: Core 4A: Small diameter portion 4B: Large Diameter part 5: Fixed side mounting plate 6: Hydraulic cylinder 7: Receiving plate 8: Moving side mounting plate 9: Pin holder 10: Molding pin group 10A: Molding pin 11: Guide pin 12: Runner 13: Gate 14: Sprue bush 15: Hydraulic cylinder C: cavity C1: cavity hole C2: cavity surface C3: cavity surface R: molding material M: porous body H: pore

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masanori Ishiguro             2-1-12 Ogimachi, Odawara-shi, Kanagawa Prefecture             Shishi Photo Film Co., Ltd. F-term (reference) 4F202 AG01 AG15 AG28 AH03 CA11                       CB01 CK11 CK35 CK42 CK52                       CK74

Claims (1)

What is claimed is: 1. When manufacturing a porous body having a plurality of pores extending in parallel with each other by injection molding, a fixed mold and a movable mold for forming a cavity corresponding to the porous body; A mold having a group of mutually parallel forming pins in which one of the fixed mold and the movable mold slidably penetrates and the tip part advances into the cavity and the tip contacts the cavity surface. A mold apparatus is used. First, a molten molding material is filled into the cavity in a state in which the tip of the molding pin group is retracted from the cavity, and then the plastic molding material in the cavity is filled. While applying pressure with the moving mold, the tip of the molding pin group is advanced into the cavity and pushed into the molding material. At this time, the plastic state in the cavity is formed according to the pushing amount of the molding pin group. The moving mold is moved away from the fixed mold through the material, and after the tip of the molding pin group comes into contact with the cavity surface, pressure is applied to the molding material in the cavity by the moving mold. A method for producing a porous body, wherein the molding material is solidified while maintaining the added state.