JP3827215B2 - Porous body manufacturing apparatus and manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a porous body manufacturing apparatus and manufacturing method , and more particularly to a manufacturing apparatus and manufacturing method suitable for manufacturing a porous body in which a plurality of pores are arranged at high density.
[0002]
[Prior art]
Conventionally, a molded product in which a plurality of pores are formed (hereinafter referred to as “porous body”) has been widely used for collimators, filters, and the like. When molding these porous bodies by injection molding, if the molding pin for forming the pores has a minute diameter of about 0.5 to 1 mm, the filling pressure of the molding material and the shrinkage when the molding material solidifies The forming pin sometimes falls or deforms due to the force. This is because the pressure distribution of the molding material in the cavity is not uniform.
Also, when molding a porous body in which a large number of pores are arranged at a high density at a narrow interval, it is necessary to arrange a large number of molding pins in the cavity at a narrow interval. If it is narrow, the molding material is difficult to enter between them, so that the molding material is insufficiently filled between the molding pins.
If the molding pin falls or deforms, or if the molding material is insufficiently filled between the molding pins, there is a problem that the pores of the porous body cannot be formed with high accuracy.
[0003]
In order to solve the above-mentioned problem, Japanese Patent Application Laid-Open No. 4-261802 discloses a core pin that molds pores in a molded body molding space (cavity) with both ends fixedly supported by a fixed mold and a movable mold. The slide insert that holds the core pin concentrically is placed so as to be movable, and when the molding material is injected into the cavity, the core pin is held by the slide insert while molding. A method is disclosed in which a slide insert is moved backward by a material filling pressure to form a molded body having pores.
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.
[0004]
Japanese Patent Laid-Open No. 7-241881 discloses a method for molding a porous body by inserting a molding pin group composed of a plurality of pins into a molding material while the molding material injected into the cavity is in a plastic state. Is disclosed. Further, when inserting the molding pin group into the molding material, the movable mold wall is moved to expand the molding body space (cavity) by an amount corresponding to the volume of the molding pin group inserted into the molding material. 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.
[0005]
Japanese Patent Application Laid-Open No. 11-216885 discloses a mold having an introduction guide portion provided so as to seal all the outlets of one of the through holes (pores of the molded body) and a molding pin for molding the through holes. , A molding material is injected into this mold in a direction parallel to the axis of the molding pin, and the 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. In other words, the molding material can be filled uniformly and sufficiently in a state of good fluidity in the gap between adjacent molding pins.
[0006]
[Problems to be solved by the invention]
However, in the method disclosed in Japanese Patent Laid-Open No. 4-261802, the core pin must be disposed in the cavity in a state where both ends thereof are fixedly supported by the fixed mold and the movable mold. There was a problem that the structure of the mold became 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 will be filled from directions other than an axial direction. Therefore, there is a problem that the molding pin falls or deforms 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 used for each molding pin. 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.
[0007]
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. The problem of being difficult to enter and insufficient filling of the molding material between the molding pins has not been solved. In addition, when inserting the molding pin group into the molding material, it is possible to prevent the breakage of the pin due to the pressure increase 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.
[0008]
Further, according to the method disclosed in Japanese Patent Application Laid-Open No. 11-216885, the flow of the molding material can be changed to a flow in a direction parallel to the molding pin, and the molding material flows in the gap between the adjacent molding pins. It is said that it can be filled uniformly and sufficiently in a good state, but 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 It has not been solved. In addition, since the molding material easily enters the portion without the molding pin between the molding pins, the molding material is filled in the cavity first from the portion without the molding pin. Therefore, the pressure distribution of the molding material filled in the cavity is not uniform, and there is a problem that the molding pin falls down or deforms due to the difference in the pressure distribution.
[0009]
Further, in the method disclosed in Japanese Patent Laid-Open No. 7-241881 and Japanese Patent Laid-Open No. 11-216885, when the molding material is filled between the molding pins, the molding is filled around the molding pins. There has been a problem that the molding pin falls or deforms due to the pressure difference of the material.
For example, as shown in FIGS. 11A to 11C, when the tip surface 20a of the molding pin 20 is formed flat, the diameter of the molding pin 20 for forming the pores is very small. Since the front end surface 20a is narrow, the pressure of the molding material R that strikes the front end surface 20a is not uniform. As a result, the molding material R that has hit the tip surface 20a of the molding pin 20 is unequally distributed around the molding pin 20 (see FIG. 11A).
[0010]
Then, as shown in FIG. 11B, a vortex of the flow of the molding material R is generated on the side (the right side in the figure) where the molding material R around the molding pin 20 is filled with much (point P in the figure). ). This point P has a negative pressure with respect to the side where the molding material R around the molding pin 20 is less filled (the left side in the figure), so that the molding pin 20 has a direction opposite to the point P (the left side in the figure). An external force (bending force) is generated in the direction toward the point P (arrow direction in the figure), and the molding pin 20 is deformed by this external force (see FIG. 11C).
In this way, when filling the molding material between the molding pins, if the flow of the molding material hitting the tip of the molding pin is unevenly distributed around the molding pin, the molding filled around the molding pin. There is a problem that a pressure difference is generated in the material, and the molding pin falls or deforms due to the pressure difference.
[0011]
Therefore, the present invention does not complicate the structure of the molding die, and the molding pin falls due to the pressure difference of the molding material in the cavity and the pressure difference of the molding material filled around each molding pin. It is an object of the present invention to provide a porous body manufacturing apparatus and a manufacturing method capable of preventing deformation and insufficient filling of a molding material between molding pins and accurately forming the pores of the porous body.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a porous body manufacturing apparatus for manufacturing a porous body in which a plurality of pores are formed in parallel to each other by injection molding, the fixed mold, and the fixed mold. A movable mold that forms a cavity between the movable mold and the movable mold or the fixed mold, and a group of molding pins parallel to each other whose leading end advances into the cavity by slidably penetrating the movable mold or the fixed mold, An injection device that fills the cavity with a molding material in a state in which a tip portion of the molding pin group is retracted from the cavity, and the plastic molding material in the cavity after the injection of the molding material by the injection device. has a molding pin puller to push the distal end portion of the forming pin groups, and emitted from the other surface with respect to the amount of incident light I which is irradiated along the axis of the pores from one surface by penetrating the pores emission Ratio of light quantity O = As O / I is 0.8 or more, the distal end portion of each forming pin of said shaped pin group, thereby forming a shape to evenly divert molding material toward the periphery of said each forming pin, said A moving mold that moves in a direction away from the fixed mold in response to the pressing of the forming pin group maintains the pressure between the space between the forming pins in the cavity and the outside of the forming pin group evenly. As described above, a brake mechanism for controlling movement of the movable mold so as to move while applying pressure to the molding material is provided .
In the present invention, the molding pin group is fixed to a pin holder, and when the molding pin group advances into the cavity in the pin holder, sliding with the movable mold or the fixed mold is guided. It is desirable to further provide a guide pin.
[0013]
With this configuration, first, since the molding material is filled into the cavity by the injection device in a state in which the tip portion of the molding pin group is retracted from the cavity, each molding pin collapses due to the flow of the molding material injected. Or deformed. Then, a molding pin group is formed by applying a pressure necessary to cause the molding pin to flow in the molding pin axial direction with respect to the molding material by the movable mold after the molding material is filled in the cavity by the molding pin driving device. Since the tip portion of the resin is pushed into the molding material in the plastic state, the molding material flows along the axial direction of the molding pin. Therefore, the molding material does not fall or deform, and the molding material can be filled between the molding pins while keeping the molding pins parallel to each other. Further, when the molding pin group is pushed in, the pressure of the molding material rises by the amount of the molding pin group entering, and the moving mold is pushed by the molding material and moves (retreats) away from the fixed mold. However, in the apparatus of the present invention, the moving mold is controlled to move backward while applying pressure to the molding material in the cavity by the moving mold by the brake mechanism, so that the molding material can be sufficiently filled between the molding pins. it can.
[0014]
In the manufacturing apparatus of the present invention, the ratio R = O of the emitted light quantity O emitted from the other surface with respect to the incident light quantity I irradiated along the axis of the fine pore through the pores of the molded body. Since the tip of each molding pin of the molding pin group is formed in a shape that evenly divides the molding material toward the periphery of each molding pin so that / I is 0.8 or more, each molding pin When the molding material is filled in between, the flow of the molding material hitting the tip of the molding pin from the cavity can be evenly divided around the molding pin. Therefore, since the molding material is uniformly filled around each molding pin, there is no pressure difference of the molding material around each molding pin, and the molding material filled around each molding pin. It is possible to prevent the forming pin from falling or deforming due to the pressure difference.
[0015]
Note that the fact that the tip of the molding pin group is retracted from the cavity does not mean that the tip of the molding pin group should not enter the cavity, but a slight cavity depending on the thickness of the molding pin. It doesn't matter if you go inside. That is, as long as each molding pin does not fall down due to the flow of the molding material to be injected, the tip portion of the molding pin group may enter the cavity.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a mold apparatus used in the porous body manufacturing apparatus of the present invention. FIG. 2 is an enlarged view of the periphery of the fixed mold and the movable mold in FIG. FIG. 3 is an enlarged view around the cavity in FIGS. In FIG. 3, the guide pins shown in FIGS. 1 and 2 are not shown, and the molding material is solidified in the cavity. FIG. 4 is an enlarged view of the tip portion of the forming pin, where (a) is a front view and (b) is a perspective view.
[0017]
As shown in FIG. 1, the mold apparatus 1 includes a fixed mold 2 and a movable mold 3, and the movable mold 3 includes a porous body M (see FIG. 1) between the fixed mold 2. And a core 4 that forms a cavity C (see FIGS. 2 and 3) corresponding to 8).
[0018]
The fixed mold 2 is attached to the fixed-side mounting plate 5, and as shown in an enlarged view in FIG. 3, a runner 12 for injecting molten resin, which is a molding material, into the cavity C in the fixed mold 2. And a gate 13 is formed. The fixed mold 2 is configured so that the upper part 2a and the lower part 2b can be separated.
[0019]
As shown in FIG. 1, the moving mold 3 is supported by hydraulic cylinders 6 and 6 attached to the moving side mounting plate 8 via a receiving plate 7, and by a driving force provided from the hydraulic cylinder 6, Pressure can be applied to the molten resin filled in the cavity C so that the pressure distribution of the molding material in the cavity C is uniform. Further, the movable mold 3 moves backward in a direction away from the fixed mold 2 in accordance with the filling pressure of the molten resin filled in the cavity C shown in FIG. 3 by controlling the hydraulic pressure of the hydraulic cylinders 6 and 6. It is also possible to move. The hydraulic cylinder 6 corresponds to a “brake mechanism”. Further, the brake mechanism is not limited to the one that generates a drag force on the molding material R in the cavity C by the hydraulic cylinder 6, but may be a brake that uses friction or a force that generates a drag force by a spring.
[0020]
A pin holder 9 slidable with respect to the moving mold 3 is attached to the moving side mounting plate 8 as shown in an enlarged view in FIG. Then, a plurality of parallel molding pins (molding) for forming a plurality of pores H (see FIG. 10) of the porous body M are formed at the tip end portion 9a of the pin holder 9 as further enlarged in FIG. The pin group 10) is fixed. Each molding pin of the molding pin group 10 is slidably penetrated through the core 4 which is a part of the movable mold 3, and a tip portion 10 a thereof is provided facing the cavity C. Further, the tip 9 a of the pin holder 9 moves to the cavity C when the moving mold 3 moves in a direction approaching or separating from the fixed mold 2 and when the forming pin group 10 slides with respect to the core 4. A guide pin 11 is provided so as to guide the movement of the core 4 and the forming pin group 10 when moving inward. The guide pin 11 penetrates the core 4 in a slidable manner.
[0021]
As shown in FIGS. 4A and 4B, the molding pin 10 has its tip portion 10 a equally dividing the flow of the molding material R hitting the tip of the molding pin 10 around the molding pin 10. In addition, it is formed in a tapered shape that decreases in diameter toward the tip.
In the present embodiment, the shape of the tip portion 10a of the forming pin 10 is formed in a tapered shape as shown in FIGS. 4 (a) and 4 (b). As long as it is a shape that can evenly distribute the flow of the molding material R that hits the periphery of the molding pin, it may be formed in another shape such as a streamline shape or a spherical shape that narrows toward the tip. Absent.
[0022]
The pin holder 9 is supported on the moving side mounting plate 8 via a hydraulic cylinder 15 which is a forming pin driving device. That is, by driving the hydraulic cylinder 15, the pin holder 9 approaches and separates from the stationary mold 2, so that the molding pin group 10 fixed to the tip end portion 9 a of the pin holder 9 can advance and retreat into the cavity C. It is possible.
The mold apparatus 1 is used by being attached to an injection molding machine (injection apparatus) (not shown), and the operation of injection and the operation of the hydraulic cylinders 6, 6 and 15 are controlled by a control apparatus (not shown). A porous body manufacturing apparatus is configured.
[0023]
Next, operation | movement of the metal mold | die apparatus 1 (manufacturing apparatus of a porous body) comprised as mentioned above is demonstrated with reference to FIGS.
[0024]
First, as shown in FIG. 5, the core 4 is moved closer to the fixed mold 2 by driving the hydraulic cylinder 6, and the space (cavity C) having the same capacity as the amount of the molding material used for the porous body after molding is fixed. It is formed between the mold 2 and the movable mold 3, and the molding pin group 10 is retracted from the cavity C by driving the hydraulic cylinder 15, and the tip 10 b of each molding pin (see FIGS. 3 and 4). ) To be flush with the cavity surface of the core 4.
[0025]
Next, as shown in FIG. 6, the molding material R is injected from the gate 13 by the injection device, and the cavity C is filled with the molding material R.
[0026]
After the cavity C is filled with the molding material R, as shown in FIG. 7, the tip 10a of the molding pin group 10 is molded in a plastic state by the hydraulic cylinder 15 while applying pressure to the molding material R with the moving mold 3. Push into material R. At this time, the movement of the pin holder 9 is guided by the guide pin 11 provided at the tip end portion 9 a of the pin holder 9 slidably penetrating the core 4. Can be slid. Since the molding material R enters between the molding pins from the tip portion 10a of the molding pin group 10 along the axial direction of the molding pin group 10, the pressure of the molding material R is uniform around the tip portion 10a of the molding pin. Thus, each forming pin does not fall down or deform.
[0027]
At this time, the volume of the cavity C is increased by the volume of the molding pin group 10 entering the molding material R, so that the pressure of the molding material R increases and the core 4 and the movable mold 3 are fixed to the fixed mold. Move in a direction away from the mold 2. The hydraulic cylinder 6 generates a resistance against the movement of the core 4 and the moving mold 3, so that pressure is applied to the molding material R through the cavity surface of the core 4. Due to this pressure, the molding material R enters the narrow gaps between the molding pins, so that the molding material R is sufficiently filled. Further, since the molding material R is sequentially filled between the molding pins with this pressure, the molding pin group 10 is kept in a state where the pressure between the space between the molding pins and the outside of the molding pin group 10 is always kept uniform. Since it is pushed into the molding material R, each molding pin does not fall down or deform. As a result, the pores of the porous body can be formed in parallel with each other.
[0028]
Further, at this time, as shown in FIG. 9, the flow of the molding material R hitting the tip portion 10a of the molding pin group 10 is evenly divided around the molding pin group 10 by the tip portion 10a. The group 10 is filled around. Therefore, each molding pin does not fall down or deform due to the pressure difference of the molding material R filled around the molding pin group 10.
[0029]
When the tip 10b of the molding pin reaches the cavity surface of the fixed mold 2, the molding material R in the cavity C is held in a pressurized state by applying pressure to the molding material R by the moving mold 3 (core 4). The molding material R is cooled and solidified with the pressure of R as uniform as possible. The cooling at this time can be performed by passing a cooling medium through the mold apparatus 1.
[0030]
When the molding material R is solidified, as shown in FIG. 8, after the upper part 2a of the fixed mold 2 is separated from the lower part 2b, the moving mold 3 is fixed by the driving force of the hydraulic cylinders 6 and 6. The porous product M is protruded from the cavity C and released from the mold by moving forward in a direction approaching the lower part 2a of the mold.
[0031]
And by removing the remaining part of the gate from the molded product manufactured by the mold apparatus 1 and opening the pores H by machining the surface molded by the fixed mold 2, As shown in FIG. 10, a porous body M in which a plurality of pores H are formed in parallel to each other can be obtained. As described above, according to the porous body manufacturing apparatus of the present embodiment, it is possible to manufacture a porous body in which pores are arranged at high density and have pores that are deeper than the diameter. . That is, according to this manufacturing apparatus, the porous body is formed so as to have through-holes, and light parallel to the hole axis is incident from one surface of the pores, and parallel to the hole axis emitted from the other surface. The amount of emitted light O was measured, and a porous body having a shape in which R (= O / I), which is a ratio of the emitted light amount O and the incident light amount I, was 0.8 or more could be formed.
[0032]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications. For example, the gate for injecting the molding material R is not limited to the illustrated part, and may be provided in the movable mold 3 or the lower part 2 b of the fixed mold 2. Further, in the embodiment, the molding pin group 10 is provided slidably with the movable mold 3. However, the molding pin group 10 is slidably provided with respect to the fixed mold 2, and the molding pin group is pushed from the cavity surface of the fixed mold 2. Further, pores can be formed in the molding material R. Further, in the embodiment, the case where the tip 10b of the molding pin group 10 is brought into contact with the cavity surface of the fixed mold 2 is exemplified, but the tip 10b of the molding pin group 10 is not brought into contact with the cavity surface, It is also possible to stop at the position inside the molding material R and form a large number of pores having a bottom in the molded body. Furthermore, by changing the cross-sectional shape and arrangement of the forming pins, the pores of the porous body are not limited to a circular cross section, but may be a polygon such as a quadrangle or a hexagon, and the arrangement thereof is also arbitrary. Can be manufactured.
[0033]
【The invention's effect】
As described above in detail, according to the present invention, the structure of the molding die is not complicated, and is caused by the pressure difference of the molding material in the cavity and the pressure difference of the molding material filled around the molding pin. It is possible to prevent collapse or deformation of the molding pins and insufficient filling of the molding material between the molding pins, and as a result, the pores of the porous body can be formed with high accuracy.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a mold apparatus used in a porous body production apparatus of the present invention.
FIG. 2 is an enlarged view of the periphery of a fixed mold and a movable mold in FIG.
3 is an enlarged view around the cavity in FIGS. 1 and 2. FIG.
FIGS. 4A and 4B are enlarged views of a tip portion of a forming pin, where FIG. 4A is a front view and FIG. 4B is a perspective view.
FIG. 5 is a cross-sectional view of the mold apparatus, showing a state before the molding material is filled in the cavity.
FIG. 6 is a cross-sectional view of a mold apparatus, showing a state in which a molding material is filled in a cavity.
FIG. 7 is a cross-sectional view of a mold apparatus, showing a state in which a tip portion of a molding pin group is pushed into a molding material.
FIG. 8 is a cross-sectional view of the mold apparatus, showing a state in which the movable mold is moved in a direction approaching the fixed mold and the molded product is protruded from the cavity and released.
FIG. 9 is a diagram showing the flow of molten resin that has hit the tip of a molding pin.
FIG. 10 is a perspective view showing a porous body manufactured by a mold apparatus.
FIGS. 11A and 11B are diagrams for explaining the flow of a molding material hitting the tip of a conventional molding pin, where FIG. 11A shows the flow of the molding material, and FIG. 11B shows the molding material flowing around the molding pin; (C) shows a state where the forming pin is deformed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mold apparatus 2 Fixed mold 3 Moving mold 4 Core 5 Fixed side mounting plate 6 Hydraulic cylinder 7 Receiving plate 8 Moving side mounting plate 9 Pin holder 10 Forming pin group 10a Tip part 11 Guide pin 12 Runner 13 Gate 15 Hydraulic cylinder C Cavity R Molding material M Porous body

Claims (4)

A porous body manufacturing apparatus for manufacturing a porous body having a plurality of pores formed in parallel to each other by injection molding,
A fixed mold,
A moving mold that forms a cavity between the fixed mold and
A mutually parallel forming pin group in which the tip part advances into the cavity by slidably penetrating the movable mold or the fixed mold,
An injection device that fills the cavity with a molding material in a state where the tip of the molding pin group is retracted from the cavity;
A molding pin driving device that pushes the tip of the molding pin group into the molding material in a plastic state in the cavity after injection of the molding material by the injection device ;
The ratio R = O / I of the amount of emitted light O emitted from the other surface to the amount of incident light I irradiated along the axis of the pore through one of the pores is 0.8 or more. The tip of each molding pin of the molding pin group is formed into a shape that evenly divides the molding material toward the periphery of each molding pin ,
A moving mold that moves in a direction away from the fixed mold in response to the pressing of the molding pin group maintains an equal pressure in the space between the molding pins and the outside of the molding pin group in the cavity. A porous body manufacturing apparatus comprising a brake mechanism for controlling movement of the movable mold so as to move while applying pressure to the molding material .   The molding pin group is fixed to a pin holder, and when the molding pin group advances into the cavity, a guide pin that guides sliding with the movable mold or the stationary mold is further provided in the pin holder. The manufacturing apparatus of the porous body of Claim 1 characterized by these.   In manufacturing a porous body in which a plurality of pores are formed in parallel to each other by injection molding, a stationary mold, a movable mold that forms a cavity between the stationary mold, and the movable mold or the above-mentioned Using a mold apparatus having a group of mutually parallel forming pins in which the tip part advances into the cavity by slidably penetrating the fixed mold,
  First, the molding material is filled into the cavity in a state where the tip of the molding pin group is retracted from the cavity,
  Next, while pushing the tip of the molding pin group into the plastic molding material in the cavity, the space between the molding pins constituting the molding pin group in the cavity, the outside of the molding pin group, The movable mold is moved in a direction away from the fixed mold while applying pressure to the molding material in the cavity with the movable mold so that the pressure of the molding material is kept uniform.
  Thereafter, the molding material is solidified in a state where pressure is applied to the molding material in the cavity by the moving mold.   The mold apparatus fixes the molding pin group to a pin holder, and guides the sliding with the movable mold or the fixed mold when the molding pin group advances into the cavity on the pin holder. The method for producing a porous body according to claim 3, further comprising a pin.

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