JP2005002452A - Method and apparatus for producing metal porous body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce uniform metal porous bodies with various shapes. <P>SOLUTION: Metal-containing slurry S is injected into a cavity 23 of a lower die 13, and thereafter, a foamed body P made of resin is filled therein. Next, the foamed body P is pressed and compressed from the upper face by an upper die 12 to remove air in the void of the foamed body P. Then, the upper die 12 is pulled up at a required speed, and the slurry S is allowed to be absorbed into the void of the foamed body P. Thereafter, the foamed body P' in which the slurry S is filled into the void is taken out from the lower die 13, and is fired to burn away the resin. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for producing a metal porous body, and more specifically, in a metal porous body production process applied to an electrode substrate, a catalyst carrier, a filter, a piston ring, a metal composite material, etc., a slurry containing metal is used. The foam is uniformly filled.
[0002]
[Prior art]
Conventionally, metal porous bodies have been used for various applications such as filters and battery electrode plates that require heat resistance, as well as catalyst carriers, piston rings, and metal composite materials.
[0003]
A conventional porous metal body is obtained by forming a metal layer on the surface of a foamed resin or the like, and then baking and removing the resin portion and reducing the metal layer. For example, in Japanese Patent Laid-Open No. 10-180166 (Patent Document 1), a band-shaped foamed resin is passed through rolls and compressed and depressurized, and a slurry containing metal powder is allowed to flow at the entrance between the rolls. A method of applying a slurry upon returning to the above is disclosed. In JP-A-6-227874 (Patent Document 2), a porous sintered body is formed by applying a solvent to spherical particles of a synthetic resin foam and then filling a slurry containing a curable resin and an inorganic powder. A manufacturing method is disclosed.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-180166
[Patent Document 2]
JP-A-6-227874 [0006]
[Problems to be solved by the invention]
However, in Japanese Patent Application Laid-Open No. 10-180166 (Patent Document 1), the strip-shaped foamed resin is compressed and decompressed by passing through a roll, and the slurry is applied with a force to return to the original shape from there. Since the slurry is sucked by the natural force that returns to step S2, the suction speed cannot be adjusted, and therefore suction may not be possible or may be suctioned only unevenly. Moreover, in this method, a seal-like porous sintered body can be manufactured, but a complicated three-dimensional shape cannot be manufactured.
[0007]
Further, in JP-A-6-227874 (Patent Document 2), when the porous sintered body to be produced is thick or has an irregular shape, the gap in the synthetic resin foam is blocked. In some cases, the slurry may not be uniformly filled, for example, when the slurry cannot be filled to the deep part of the gap. Therefore, there is a problem that a uniform porous sintered body cannot be formed.
[0008]
The present invention has been made in view of the above-described problems, and enables the production of a uniform porous metal body, the formation of various shapes of the porous metal body, and the complexity and productivity of the apparatus. It is a problem to improve.
[0009]
Means to be Solved by the Invention
In order to solve the above problem, the present invention fills the resin foam after injecting the metal-containing slurry into the cavity of the lower mold,
The foam is pressed from above with a top mold and compressed to remove air in the voids of the foam,
The upper mold is pulled up at a required speed, the slurry is sucked into the voids of the foam, and then the foam filled with the slurry is taken out from the lower mold,
There is provided a method for producing a porous metal body characterized in that the resin is burned off by firing.
[0010]
With the above configuration, by pressing the foam with the upper mold, air in the voids of the foam can be removed, and the foam is compressed by pulling up the upper mold at a required speed. When returning from the state to the original shape, the slurry can be sucked into the gap. In addition, instead of compressing the foam by passing it through a roll as in the prior art, in the present invention, the foam is uniformly pressed between the upper mold and the lower mold and is unloaded uniformly. As a result, the slurry can be uniformly filled in the foam. Therefore, a metal porous body in which the pores are uniformly arranged can be obtained by removing the foam filled with the slurry from the lower mold and baking it.
[0011]
In addition, since the above manufacturing method only presses and unloads between the upper mold and the lower mold, a three-dimensional complex just by changing the shape of the mold cavity and the shape of the foam to the desired shape. Therefore, it is possible to cope with the production of a porous metal body having a different shape. Furthermore, since the slurry can be easily adsorbed uniformly to the foam and almost all of the slurry can be sucked in, the material such as the slurry is not wasted and the cost can be reduced. In addition, since the slurry can be filled into the foam only by pressing / pulling once, the productivity is excellent.
[0012]
It is preferable that the pulling speed when pulling up the upper mold is set to be equal to or lower than the speed at which the foam returns to the original shape.
[0013]
As described above, by setting the pulling speed of the upper mold to be pulled up to the speed at which the foam returns to the original shape, the slurry can be surely sucked when the foam returns to the original shape. The slurry can be filled uniformly.
Also, the pulling speed of the upper mold is preferably slower than the returning speed while the foam returns to the original shape, but the foam is required until the restoration rate reaches about 30 to 40% in order to increase productivity. It is more preferable that the speed is slower than the speed at which the speed returns, and then the speed is about the same as the speed at which the speed returns. Thereby, a slurry can be filled more uniformly into a foam.
[0014]
As the metal-containing slurry, it is preferable to use a metal powder and a binder to obtain a required viscosity, and it is preferable to use urethane foam as the foam.
[0015]
As the metal powder, it is preferable to use at least one powder selected from Fe, Cr, Ni, Mo, Al, P, B, Si, and / or a metal oxide powder thereof. The binder is preferably a thermosetting resin such as a phenol resin, and the viscosity is preferably 4000 to 16000 cps. In addition, urethane foam is preferably used as the foam, and polystyrene foam, epoxy foam, polyvinyl chloride foam, phenol resin foam, silicon foam, polyacrylic foam, and the like can also be used.
[0016]
Moreover, after taking out the said foam from a lower metal mold | die, after passing through drying and a binder removal, the said baking is performed, and after that, it sets in a shaping | molding metal mold | die and correct | amends to a required shape by press molding.
[0017]
Since the shape of the metal porous body obtained by firing is not necessarily in accordance with the specifications due to thermal expansion, etc., the metal porous body is inserted into a shaping mold having the required specifications and then pressed to correct the shape. Thus, a metal porous body having a desired shape can be obtained.
[0018]
Before firing the foam, it is dried in a drying furnace that can be controlled at 70 to 150 ° C., heat-treated in a binder removal furnace that can be controlled at 500 to 900 ° C., and fired in a firing furnace that can be controlled at 400 to 1300 ° C. Good. Therefore, at the same time as removing the foam, it is possible to carbonize a thermosetting resin such as phenol resin and reduce the metal oxide using it as a reducing agent, so that the foam filled with the slurry is made into a metal porous body. It becomes possible.
[0019]
Secondly, the present invention provides a lower mold which can be filled with a required amount of slurry and foam and has a space volume for air escape from the voids of the foam,
An upper mold that presses the upper surface of the foam filling the lower mold and is movable up and down in the space of the lower mold;
There is provided an apparatus for producing a porous metal body, comprising the upper mold up-and-down driving means.
[0020]
With the apparatus having the above-described configuration, the necessary material can be placed on the lower mold, and the material can be pressed by the upper and lower molds by the vertical drive means, so that the apparatus is not complicated and the operation is simple. And can increase productivity.
[0021]
The width between the side walls of the cavity of the lower mold is set to be larger than the width of the convex part of the upper mold, and the gap between the convex part and the cavity serves as an air escape part.
[0022]
With the above configuration, when the air inside the foam is removed by pressing with the upper mold, the removed air may escape to the outside through the gap between the convex part of the upper mold and the cavity of the lower mold. And the air inside the foam can be completely removed. Further, the slurry fills the gap as the air escape portion, so that when the upper mold is pulled up, only the slurry can be sucked from the side surface of the foam without containing air.
[0023]
A taper portion that is wider toward the upper side than the air escape portion is provided on the side wall of the recess of the lower mold.
[0024]
With the above configuration, when the foam is contracted by pressing the upper die, the slurry overflowing from the air escape portion can escape to the taper portion and accumulate, so that the slurry overflows from the concave portion of the lower die. Can be prevented. In addition, the slant of the taper part causes the slurry to flow into the air escape part of the gap between the lower mold and the foam and close it. Therefore, when the upper mold is pulled up and the slurry staying in the air escape part is sucked into the foam In addition, air can be prevented from being inhaled. Therefore, it becomes possible to fill only the slurry without containing air in the voids of the foam.
The inclination angle of the taper portion is preferably set so that the slurry surely flows into the air escape portion in consideration of the viscosity of the slurry. For example, when the viscosity of the slurry is high, the inclination angle of the taper portion is set. A steep slope may be used.
[0025]
In the above apparatus, a take-out treatment provided with a holding part that is detachably attached in the space of the lower mold and holds at least the lower surface of the foam from the outer peripheral side, and a handle part connected to the holding part. It is preferable to provide a tool.
[0026]
By providing the take-out jig, when taking out the foam filled with the slurry from the mold, it is possible to prevent the shape from being deformed by its own weight or to adhere to the lower mold. If the shape breaks down, the shape must be significantly corrected after firing, and at that time, the foam is damaged and the strength is lowered. Therefore, it is preferable to take out the shape while maintaining the shape by using the above-mentioned extraction jig.
The material of the take-out jig is not limited as long as it has rigidity capable of lifting the foam that has sucked the slurry, and metal, resin, or the like is used.
[0027]
In the above apparatus, the slurry injection machine capable of controlling the amount of slurry injected into the lower mold, and the foam or the take-out jig holding the foam are set in the lower mold and are taken out from the lower mold after slurry filling. What comprises a robot arm is preferable.
[0028]
When the slurry is stored in the cavity of the lower mold, the slurry injection amount can be kept constant and can be uniformly injected into the cavity of the lower mold.
In addition, the robot arm can automatically set the foam in the lower mold and take out the foam filled with the slurry from the lower mold, enabling automatic continuous production of the metal porous body.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic view of a metal porous body manufacturing apparatus 10 according to a first embodiment of the present invention, in which a base 16 having a bottom wall 16a and a side wall 16b, and a lower metal mounted on the bottom wall 16a of the base 16 is shown. A mold 13, a vertical driving means 11 that is rotatably connected to a side wall 16 b of the pedestal 16, and an upper mold 12 that is suspended from the vertical driving means 11 are provided.
The vertical drive means 11 connects the swing member 18 to the upper end of the side wall 16b of the pedestal 16 via the rotary shaft 17, and is placed on the lower surface side of the horizontal plate 21 at the lower end of the support portion 19 hanging from the center of the swing member 18. The upper mold 12 is attached to the upper mold 12 itself as a convex portion, and the upper mold 12 is moved up and down by moving the end 18a of the swing member 18 up and down.
[0030]
As shown in FIGS. 2A and 2B, the upper mold 12 has an annular shape with a width W1, and the lower surface facing the lower mold 13 has a tip flat surface 12a and the tip flat surface. Inclined portions 12b and 12c on both sides of 12a are provided and tapered slightly downward.
As shown in FIGS. 3A and 3B, the lower mold 13 has a circular shape having a cavity 23 that is an annular recess, and the cavity 23 includes a groove portion 23a having a width W2, and a groove portion. And a taper portion 23b which is widened upward from both side walls of 23a.
The magnitude relationship between the width W1 of the upper mold 12 and the width W2 of the groove 23a of the cavity 23 of the lower mold 13 is W1 <W2.
[0031]
Further, in order to make it easy to take out the polyurethane foam P, which will be described later, from the lower mold 13, a take-out jig 15 installed in the cavity 23 of the lower mold 13 is provided. As shown in FIG. 4, the take-out jig 15 includes an outer frame 15 a having substantially the same shape as the outer frame of the lower mold 13, and an L-shaped rod-shaped holding member protruding downward from the outer frame 15 a with a space therebetween. A portion 15b and a handle portion 15c connected to a part of the outer frame 15a are provided.
The handle 15c of the take-out jig 15 is attached to the tip 30a of the robot arm 30, and can be automatically conveyed.
Further, a slurry injector 14 for injecting the slurry S into the cavity 23 of the lower mold 13 is provided, and the slurry injector 14 has a scale 14a on the outer surface of the cylinder to keep the injection amount of the slurry S constant. It is possible.
[0032]
Hereinafter, the manufacturing method of the metal porous body using the said manufacturing apparatus 10 is demonstrated. The method for producing a porous metal body of the present invention comprises a step of filling a slurry with a slurry and a step of firing the filled foam.
Here, 50% by weight of Fe ₂ O ₃ powder as slurry, 23% by weight of FeCr (Cr60%) alloy powder, 17% by weight of 65% aqueous phenol resin solution as thermosetting resin, and 2% by weight of CMC (carboxymethylcellulose) as dispersant Using a polyurethane foam P having a thickness of 10 mm as a foam, a mixture prepared by mixing at a blending ratio of 8% by mass of water and water was used.
[0033]
First, the process of filling the polyurethane foam P with the slurry S will be described.
Next, as shown in FIG. 1 and FIG. 5 (A), about 30 g of slurry S is injected into the cavity 23a using the slurry injector 14, and then the take-out jig 15 on which the annular polyurethane foam P is placed is placed. The holding unit 15 b is positioned in the cavity 23 by being automatically conveyed by the robot arm 30. The width of the polyurethane foam P is narrower than the width W2 of the groove 23a of the cavity 23 of the lower mold 13.
[0034]
Next, by lowering the handle 18a of the swing member 18, the annular upper mold 12 presses the upper surface of the polyurethane foam P as shown in FIG. While removing the air, the polyurethane foam P is contracted to the actual volume excluding the air by pushing in until the gap T between the upper mold 12 and the lower mold 13 is about 1 mm. At this time, the air taken out from the polyurethane foam P is discharged to the outside using the gap ΔW between the upper mold 12 and the cavity 23 of the lower mold 13 as an air escape portion, and the slurry S is also above the gap ΔW. And the slurry S is retained in the tapered portion 23b which is a slurry reservoir. Since the slurry reservoir is a tapered portion 23b, the slurry S does not overflow from the cavity 23 to the outside.
[0035]
After holding in this state for about 1 second, as shown in FIG. 5 (C), the upper mold 12 is lifted upward, and the polyurethane foam P is restored to its original shape to restore the internal gap. The slurry S is absorbed, and the polyurethane foam P is filled with the slurry S.
At this time, until the height of the polyurethane foam P is restored to about 3 to 4 mm, the speed is the same as or slower than the speed at which the polyurethane foam P self-restores. Thereafter, the upper mold 12 is pulled up at the same speed as the speed at which the polyurethane foam P self-restores.
[0036]
According to the above method, since the upper mold 12 is pulled up at a speed lower than the rate at which the polyurethane foam P self-restores, the upper surface of the polyurethane foam P is kept in the closed state. Air is not sucked from the upper surface of P. Further, the slurry S stays in the tapered portion 23a, and the slurry S existing in the tapered portion 23b extends along the inclined surface in the gap formed between the side surface of the polyurethane foam P and the cavity 23 of the lower mold 13 in the restoration process. It flows in under its own weight, and the gap is always filled with the slurry S and no air is present.
Therefore, by pulling up the upper mold 12 below the speed at which the polyurethane foam P self-restores, the polyurethane foam P can reliably suck only the slurry S, and obtain the polyurethane foam P uniformly filled with the slurry S. I can do it. In addition, the inclination angle of the taper portion 23b is set to an angle at which the slurry S having viscosity can flow into the gap.
[0037]
Then, by pulling up the handle portion 15c of the take-out jig 15 by the robot arm 30, the polyurethane foam P ′ uniformly filled with the slurry S is taken out from the lower mold 13 while being placed on the holding portion 15b. As a result, the polyurethane foam P ′ filled with the slurry S and heavier can be taken out without being bonded to the cavity 23 and without losing its shape.
[0038]
As a modification of the take-out jig 15, the lower surface of the polyurethane foam P may be supported by a mesh portion. Specifically, as shown in FIGS. 6 (A) and 6 (B), the take-out jig 15 ′ of the modified example includes an outer frame 15a ′ having substantially the same shape as the outer frame of the lower mold 13, and an outer frame 15a ′. A rod-shaped side portion 15b 'protruding downward with a gap, a handle portion 15c' connected to a part of the outer frame 15a, and a ring-shaped net projecting inward from the lower end of the side portion 15b ' Bottom surface portion 15d '. In this way, the polyurethane foam P can be stably held by the bottom surface portion 15d ′.
[0039]
Next, the process of baking the polyurethane foam P ′ uniformly filled with the slurry S as described above will be described.
The polyurethane foam P ′ is dried in a drying oven at 120 ° C. to remove moisture. The dried polyurethane foam P ′ is carbonized by incinerating the polyurethane foam P ′ in a debinding furnace at 600 ° C. and incinerating the phenol in the slurry S. When a metal oxide of Fe and Cr is reduced with the carbonized component in a firing furnace at 1100 ° C., and the reduced metal component of Fe and Cr is alloyed and fired, a porous metal body can be obtained. Finally, the metal porous body is set in another shaping mold and corrected to a required shape by press molding.
By the manufacturing method described above, a porous metal body in which pores are uniformly dispersed can be obtained.
[0040]
【The invention's effect】
As is clear from the above description, according to the manufacturing method of the present invention, the foam is removed by pressing the foam with the upper mold to remove the air in the foam and raising the upper mold to unload. When restoring, the metal-containing slurry is absorbed into the inside of the foam, so even if it is a three-dimensional complicated shape by simply changing the shape of the foam to the shape of the desired specification It is possible to uniformly fill the slurry, and it is possible to produce metal porous bodies having various shapes. Furthermore, the slurry can be uniformly filled with the foam by setting the lifting speed of the upper die below the speed at which the foam self-restores. Therefore, when the foam is fired, a porous metal body in which the metal is uniformly dispersed can be produced.
[0041]
Further, according to the production apparatus of the present invention, since the apparatus is not complicated, the slurry can be uniformly filled into the foam by a simple operation when the apparatus is used, and thus the productivity is excellent. In addition, since all the necessary amount of slurry can be filled in the foam, the material is not wasted and the cost is excellent.
[Brief description of the drawings]
FIG. 1 is a schematic view of a manufacturing apparatus according to a first embodiment of the present invention.
2A is a perspective view of an upper mold, FIG. 2B is a cross-sectional view thereof, and FIG. 3A is a perspective view of a lower mold, and FIG.
4A is a top view of the take-out jig, and FIG. 4B is a perspective view.
FIGS. 5A to 5C are cross-sectional views showing a process of filling a foam with slurry. FIGS.
6A is a top view of a take-out jig according to a modification, and FIG. 6B is a perspective view.
[Brief description of symbols]
DESCRIPTION OF SYMBOLS 10 Manufacturing apparatus 11 Vertical drive means 12 Upper metal mold 13 Lower metal mold 14 Slurry injection machine 15 Extraction jig 23 Cavity 23a Groove part 23b Tapered part S Slurry P Polyurethane foam (foam)

Claims (9)

After injecting a metal-containing slurry into the cavity of the lower mold, it is filled with a resin foam,
The foam is pressed from above with a top mold and compressed to remove air in the voids of the foam,
The upper mold is pulled up at a required speed, the slurry is sucked into the voids of the foam, and then the foam filled with the slurry is taken out from the lower mold,
A method for producing a porous metal body, characterized in that the resin is burned off by firing. The method for producing a porous metal body according to claim 1, wherein a pulling speed when pulling up the upper mold is set to be equal to or lower than a speed at which the foam returns to its original shape. The method for producing a porous metal body according to claim 1, wherein urethane foam is used as the foamed body. The foam is taken out from the lower mold, dried and debindered and then baked, and then set in a molding mold and corrected to a required shape by press molding. The manufacturing method of the metal porous body of any one of Claims 1 thru | or 3. A lower mold which can be filled with a required amount of slurry and foam and has a space volume for air escape from the voids of the foam;
An upper mold that presses the upper surface of the foam filling the lower mold and is movable up and down in the space of the lower mold;
An apparatus for producing a porous metal body, comprising: an upper / lower drive means for the upper mold. 6. The width between the side walls of the cavity of the lower mold is set to be larger than the width of the convex part of the upper mold, and the gap between the convex part and the cavity serves as an air escape part. The manufacturing apparatus of the metal porous body as described in any one of. The apparatus for producing a metal porous body according to claim 6, wherein a taper portion that is wider toward the upper side than the air escape portion is provided on a side wall of the cavity of the lower mold. A take-off jig is provided that is detachably attached in the space of the lower mold and includes a holding portion that holds at least the lower surface of the foam from the outer peripheral side, and a handle portion that is connected to the holding portion. The metal porous body manufacturing apparatus according to any one of claims 5 to 7, wherein the metal porous body manufacturing apparatus is provided. A slurry injector capable of controlling the amount of slurry injected into the lower mold, and a robot arm for setting the foam or the take-out jig holding the foam to the lower mold and taking out from the lower mold after slurry filling. The apparatus for producing a metal porous body according to any one of claims 5 to 8, wherein the apparatus is provided.

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