JP2020132992A - Powder sintering device - Google Patents

Abstract

To provide a powder sintering device capable of enhancing uniformity of density of a sintered body in a width direction and achieving high productivity by continuous production.SOLUTION: A powder sintering device 50 comprises: a powder transport mechanism 101 for transporting a powder material 1 to a transport direction X; a pair of rolls facing each other with a gap 52 therebetween, arranging the powder material 1 to be transported by the powder transport mechanism 101 in the gap 52 for heating and compressing the same; a cavity formation part 301 for partially blocking a transport path of the powder material 1 heated and compressed by the pair of rollers in the gap 52, for forming a cavity on a sintered body 2 formed of the powder material 1 along the transport direction X; and a cutting part 401 for cutting the sintered body 2 along the cavity formed by the cavity formation part 301.SELECTED DRAWING: Figure 1

Description

The present invention relates to a powder sintering apparatus for sintering powder.

By press-molding ceramic or metal powder and then heat-treating it at a temperature below the melting point, bonds between the powders occur and a sintered body can be obtained. This method is the main method for manufacturing ceramic products, ceramics, powder metallurgy, cermets and the like.

Examples of the sintering method include a normal pressure sintering method, a gas pressure sintering method, a hot press method, a hot hydrostatic pressure method (HIP), an energization pressurization method, and a millimeter wave method.

In order to obtain a more dense sintered body, it is effective to heat the powder molded body in a pressurized state by a gas pressure sintering method, a hot press method, a hot hydrostatic pressure method, an energization pressurization method, or the like.

These methods are batch processing, and continuous processing is effective for increasing productivity. For example, Patent Document 1 shows that a sheet can be formed by heating a metal powder and pressurizing it with a pair of rolling rolls.

Here, in the pressurization with the roll, the pressing force of the roll tends to decrease at the widthwise end portion of the powder material during rolling, and more unsintered portions are generated as compared with the widthwise central portion, and the density tends to decrease. .. Therefore, the density of the sintered body in the width direction becomes non-uniform. In order to solve such a problem, Patent Document 2 proposes a method of using a pair of rolls in which a protrusion is provided on one roll and a groove is provided on the other roll.

In the pair of rolls disclosed in Patent Document 2, tapered portions are provided at both ends of the protrusion and the groove. By combining the roll protrusion having such a tapered portion and the roll groove portion, it is possible to prevent the pressing force of the roll from decreasing at the widthwise end portion of the powder material and reduce the density of the widthwise end portion of the sintered body. It is an attempt to suppress it.

Special table 2003-520292 JP 2000-234105

However, in the method disclosed in Patent Document 2, the powder material bites into the groove of the roll, and it becomes difficult to release the sintered body. Further, it is disclosed that the roll can be divided and the spacer spacing can be adjusted so that the width of the powder material can be changed. However, it is necessary to install a roll for the division method, and the roll The operating rate drops because it involves replacement. Therefore, it is difficult to achieve high productivity.

Therefore, an object of the present invention is to provide a powder sintering apparatus capable of realizing high productivity by continuous production while increasing the uniformity of density in the width direction of the sintered body.

In order to achieve the above object, the powder sintering apparatus of the present invention comprises a powder transfer mechanism for transporting a powder material in a transport direction and a pair of rolls facing each other with a gap. A pair of rolls in which the powder material transported by the transport mechanism is placed in the gap and heated and pressurized, and a transport path of the powder material heated and pressurized by the pair of rolls are partially provided in the gap. A void forming portion that forms a void in the sintered body made of the powder material along the transport direction by blocking, and a cutting portion that cuts the sintered body along the void formed by the void forming portion. And.

According to the powder sintering apparatus of the present invention, it is possible to realize high productivity by continuous production while increasing the uniformity of density in the width direction of the sintered body.

Schematic diagram of the powder sintering apparatus in the embodiment Sectional drawing which shows the positional relationship of a pair of rolls and a wire in an embodiment AA'cross-sectional view of FIG. BB'cross section of FIG. FIG. 1 is a cross-sectional view taken along the line CC'. FIG. 1 is a cross-sectional view taken along the line DD'.

According to the first aspect of the present invention, the powder transport mechanism for transporting the powder material in the transport direction and a pair of rolls facing each other with a gap, and the powder transported by the powder transport mechanism. The powder material is formed by partially blocking the transport path of the pair of rolls in which the body material is placed in the gap and heated and pressed by the pair of rolls and the powder material heated and pressed by the pair of rolls in the gap. A powder firing portion comprising a void forming portion for forming a void along the transport direction and a cutting portion for cutting the sintered body along the void formed by the void forming portion. Provide a binding device.

According to the second aspect of the present invention, the gap forming portion provides the powder sintering apparatus according to the first aspect, comprising a wire that traverses the gap between the pair of rolls in the transport direction.

According to the third aspect of the present invention, the gap forming portion includes a first support portion that supports the wire from above on the upstream side in the transport direction from the gap, and a downstream side in the transport direction from the gap. The powder sintering apparatus according to the second aspect is further provided with a second support portion for supporting the wire from above.

According to the fourth aspect of the present invention, the powder sintering apparatus according to the third aspect, wherein the first support portion and the second support portion are configured so that the wire can be wound up.

According to the fifth aspect of the present invention, the wire is arranged on one side in the width direction of the powder material conveyed in the transfer direction and on the other side in the width direction. The powder sintering apparatus according to any one of the second to fourth aspects is provided, which comprises a second wire.

According to the sixth aspect of the present invention, the powder sintering apparatus according to any one of the second to fifth aspects, wherein the diameter of the wire is smaller than the distance between the gaps of the pair of rolls. provide.

According to the seventh aspect of the present invention, the void forming portion is any one of the first to sixth aspects, wherein the void forming portion forms a groove extending along the conveying direction on the surface of the sintered body as the void. The powder sintering apparatus described in the above is provided.

(Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a powder sintering apparatus 50 according to an embodiment. The powder sintering apparatus 50 shown in FIG. 1 is an apparatus for sintering a powder material 1 to obtain a sintered body 2. The powder sintering apparatus 50 includes a powder transport mechanism 101, a heating and pressurizing mechanism 201, a void forming portion 301, a cutting portion 401, and a material recovery mechanism 501.

The powder material 1 is, for example, an aggregate of particles having a particle size smaller than 100 μm, and its particle size distribution is not limited at all. The powder material 1 may be previously subjected to a molding process for adjusting the thickness and width. As the molding process, for example, a method of compression molding the powder into a sheet using a pair of rolls or a method of pressing the powder using a mold can be performed.

The powder transport mechanism 101 is a mechanism for transporting the powder material 1 in the transport direction X. The powder transfer mechanism 101 has a function of supplying the powder material 1 to the heating / pressurizing mechanism 201. The transport direction X in the embodiment is the horizontal direction. The powder transfer mechanism 101 is composed of, for example, a belt conveyor. As the belt conveyor, a steel belt, a mesh belt, or the like can be used.

The heating and pressurizing mechanism 201 is a mechanism that pressurizes the powder material 1 while heating it. The heating and pressurizing mechanism 201 includes a first roll 11 and a second roll 12 as a pair of rolls. The first roll 11 and the second roll 12 heat and pressurize the powder material 1 transported in the transport direction X while sandwiching it from both sides. In the embodiment, the first roll 11 and the second roll 12 are arranged vertically, and the powder material 1 is vertically sandwiched between the upper first roll 11 and the lower second roll 12 to heat and pressurize.

A gap 52 is formed between the first roll 11 and the second roll 12. The gap 52 is a proximity point where the first roll 11 and the second roll 12 are closest to each other. In the gap 52, the powder material 1 is heated and pressed by the first roll 11 and the second roll 12, and the sintered body 2 is produced.

The powder transfer mechanism 101 described above has a function of supplying the sintered body 2 to the cutting portion 401 and the material recovery mechanism 501.

The materials of the rolls 11 and 12 are not particularly limited, but metals such as stainless steel, carbon steel and high-speed tool steel, and ceramics such as silicon nitride, silicon carbide, alumina, sialon and zirconia may be used. it can. Furthermore, a structure in which these materials are combined can also be used.

The heating temperature of the rolls 11 and 12 may be set to, for example, 400 ° C. or higher and 700 ° C. or lower. By setting the temperature to 400 ° C. or higher, the temperature of the powder material 1 can be sufficiently raised, and a high-density sintered body 2 can be obtained. Further, by setting the temperature to 700 ° C. or lower, the temperature rise of the shaft portion of the rolls 11 and 12 can be suppressed, and the life of the bearing supporting the shaft portion can be extended.

Further, although not shown, it is also possible to preheat the powder material 1 before reaching the heating / pressurizing mechanism 201. The preheating means is not particularly limited, but a heating furnace, a sheathed heater, a ceramic heater, a halogen lamp heater, a carbon heater, a flash lamp heater, or the like can be used.

The heating and pressurizing mechanism 201 further includes a first heating device 13 and a second heating device 14 as members for heating the rolls 11 and 12. The first heating device 13 is a member that heats the first roll 11, and the second heating device 14 is a member that heats the second roll 12. The heating devices 13 and 14 are not particularly limited, but induction heating coils, sheathed heaters, halogen lamp heaters, carbon heaters, flash lamp heaters and the like can be used.

In the atmosphere for heating the powder material 1, the atmosphere can be controlled to be an inert atmosphere by using nitrogen (N ₂ ) or the like, if necessary.

The void forming portion 301 is a member that forms voids in the sintered body 2 by partially blocking the transport path of the powder material 1 that is heated and pressed by the rolls 11 and 12. By forming such a gap, the end portion in the width direction of the sintered body 2 can be easily cut by the cutting portion 401 described later. By cutting the widthwise end of the sintered body 2 whose density tends to be low, it is possible to suppress variations in the density of the sintered body 2 in the width direction, and to obtain a sintered body 2 having a more uniform density. Can be done. The detailed configuration of the void forming portion 301 will be described later.

The cutting portion 401 is a member that cuts the sintered body 2 along the voids formed by the void forming portion 301. As the cutting portion 401, a means for separating by a mechanical impact such as a hammer, a rotary blade, an air jet, a sand blast, or a dry ice blast, or a means for giving a non-contact thermal shock such as a laser cut or a flash lamp is used. Can be done. The cut portion 401 functions as an end portion separating mechanism for separating the widthwise end portions of the sintered body 2.

The material recovery mechanism 501 is a mechanism for recovering the sintered body 2 after being cut by the cutting portion 401. The material recovery mechanism 501 may, for example, cut the sintered body 2 to a certain length and then recover it in the form of a sheet. It is also possible to crush the sintered body 2 into flakes, which are finer than the sheet, and then recover the sintered body 2.

Next, the detailed configuration of the void forming portion 301 will be described.

As shown in FIG. 1, the gap forming portion 301 includes a wire 21, a winding mechanism 22, a winding mechanism 23, and guide rolls 24 and 25.

The wire 21 is a linear member that is passed through a gap 52 between the pair of rolls 11 and 12. A gap is formed in the sintered body 2 by the wire 21 partially blocking the transport path of the powder material 1 with the gap 52.

The wire 21 of this embodiment is a metal wire made of metal. The material of the metal wire is not particularly limited, but stainless steel can be used.

The winding mechanism 22 and the winding mechanism 23 are members that enable the wire 21 to be wound. The wire 21 unwound by the unwinding mechanism 23 is unwound by the unwinding mechanism 22.

The winding mechanism 22 and the unwinding mechanism 23 function as a first support portion and a second support portion that support the wire 21, respectively. The winding mechanism 22 is a first support portion that supports the wire 21 from above on the upstream side of the gap 52 in the transport direction X. The unwinding mechanism 23 is a second support portion that supports the wire 21 from above on the downstream side of the gap 52 in the transport direction X. The wire 21 is passed through the gap 52 in a state of being suspended from above by the winding mechanism 22 and the unwinding mechanism 23. The wire 21 provided in this way traverses the gap 52 in the transport direction X.

The guide rolls 24 and 25 are rolls for guiding the wire 21.

The positional relationship between the pair of rolls 11 and 12 and the wire 21 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a pair of rolls 11, 12 and wires 21 in the gap 52 when viewed from the transport direction X.

In FIG. 2, the powder material 1 arranged in the gap 52 is shown by a dotted line.

As shown in FIG. 2, the wire 21 of the present embodiment includes a first wire 21A and a second wire 21B as a pair of wires. The first wire 21A is a wire provided on one side in the width direction Y, and the second wire 21B is a wire provided on the other side in the width direction Y. The first wire 21A is arranged near one end of the powder material 1 in the width direction Y, and the second wire 21B is arranged near the other end of the powder material 1 in the width direction Y. By providing such a pair of the first wire 21A and the second wire 21B, voids can be formed at both ends of the sintered body 2 in the width direction Y.

As shown in FIG. 2, the two wires 21A and 21B are arranged so as to come into contact with the lowermost surface of the first roll 11. As a result, the voids formed in the sintered body 2 become grooves exposed on the surface of the sintered body 2. It should be noted that not only when the wire 21 comes into contact with the lowermost surface of the first roll 11, but also when the wires 21 are arranged at intervals from the lowermost surface of the first roll 11, a groove exposed on the surface of the sintered body 2 is formed. You can also.

The diameter D2 of the wire 21 is designed to be smaller than the distance D1 with respect to the distance D1 of the gap 52, which is the distance between the rolls 11 and 12. As a result, the wire 21 can be reliably arranged in the gap 52. Further, when the wire 21 is maintained, the wire 21 can be taken out from between the rolls 11 and 12 without changing the positions of the rolls 11 and 12.

Here, the AA'cross section, the BB'cross section, the CC'cross section, and the DD'cross section shown in FIG. 1 are shown in FIGS. 3A to 3D. 3A shows a cross section of AA', FIG. 3B shows a cross section of BB', FIG. 3C shows a cross section of CC', and FIG. 3D shows a cross section of DD'.

As shown in FIG. 3A, the powder material 1 transported to the gap 52 by the powder transport mechanism 101 is transported in the form of a sheet having a rectangular cross section. The thickness of the powder material 1 is substantially constant in the width direction Y.

The cross section shown in FIG. 3B corresponds to the gap 52, in which the rolls 11 and 12 heat and pressurize the powder material 1. The powder material 1 is heated and pressed by the rolls 11 and 12 to become the sintered body 2. As shown in FIG. 3B, two wires 21A and 21B are provided so as to partially block the transport path of the powder material 1. A gap 54 of the sintered body 2 is formed at a position where the wires 21A and 21B are located. By forming such a gap 54, the sintered body 2 is divided into an end portion 31 and 32 in the width direction Y and a central portion 33 located between the end portions 31 and 32.

As shown in FIG. 3B, the sintered body 2 has a thickness D3. The diameter D2 of the wire 21 is set to 1/2 or more of the thickness D3 of the sintered body 2. As a result, a void 54 having a desired size can be formed.

The cross section shown in FIG. 3C corresponds to a position downstream of the gap 52 and upstream of the cutting portion 401. As shown in FIG. 3C, although the wires 21A and 21B are separated from the sintered body 2, the voids 54 formed by the gaps 52 are continuously formed. By continuously feeding the powder material 1 and the sintered body 2 in the transport direction X, voids 54 continuously extending along the transport direction X are formed in the sintered body 2.

The gap 54 is used for cutting by the cutting portion 401 (FIG. 1) described above. Specifically, the cutting portion 401 cuts the sintered body 2 along the gap 54.

FIG. 3D shows the state after cutting by the cutting portion 401. As shown in FIG. 3D, the end portions 31 and 32 of the sintered body 2 in the width direction Y are cut and separated from the central portion 33. At the ends 31 and 32 in the width direction Y, there is a space for the powder material 1 to escape to the outside, and the pressing force by the rolls 11 and 12 is weakened. Therefore, unsintered portions that are not sufficiently sintered are likely to occur at the end portions 31 and 32, and the density tends to be lower than that of the central portion 33. On the other hand, by forming gaps 54 near both ends of the sintered body 2 in the width direction Y and cutting the end portions 31 and 32 along the gaps 54, the end portions 31 of the sintered body 2 having a low density are formed. , 32 can be removed. As a result, the central portion 33 having a less unsintered portion and a more uniform density can be recovered as the sintered body 2.

In the present embodiment, the gap 54 is formed only by arranging the wire 21 between the rolls 11 and 12. Therefore, the void 54 can be formed in the process of continuous production by the rolls 11 and 12, and high productivity can be realized. Further, since cutting by the cutting portion 401 is also performed in the process of continuous production, high productivity can be realized.

When a void is formed in the powder material 1 on the upstream side of the gap 52, the void cannot be formed because the void is buried by the material flow during the subsequent heat and pressurization treatment. In the present embodiment, the wire 21 is passed through the gap 52 where the heat and pressure treatment is performed so that the void 54 is formed in the sintered body 2.

As described above, the powder sintering apparatus 50 of the present embodiment includes a powder transfer mechanism 101, a pair of rolls 11 and 12, a void forming portion 301, and a cutting portion 401. The gap forming portion 301 partially blocks the transport path of the powder material 1 heated and pressed by the pair of rolls 11 and 12 with the gap 52, so that the gap 54 is formed in the sintered body 2 along the transport direction X. To form. The cutting portion 401 cuts the sintered body 2 along the gap 54 formed by the gap forming portion 301. According to such a configuration, by cutting the sintered body 2 along the gap 54, the portions 31 and 32 in the width direction Y where the density tends to be low in the sintered body 2 can be removed. As a result, the central portion 33, which is a portion where the density in the width direction Y has little variation, can be recovered as the sintered body 2. Further, since the gap 54 can be formed and cut in the process of continuous production using the pair of rolls 11 and 12, high productivity can be realized.

Further, according to the powder sintering apparatus 50 of the embodiment, the void forming portion 301 includes a wire 21 that traverses the gap 52 of the pair of rolls 11 and 12 in the transport direction X. According to such a configuration, the void 54 can be formed by a simple configuration.

Further, according to the powder sintering apparatus 50 of the embodiment, the void forming portion 301 includes a winding mechanism 22 and a winding mechanism 23. The winding mechanism 22 is a first support portion that supports the wire 21 from above on the upstream side of the transport direction X from the gap 52, and the unwinding mechanism 23 is the wire 21 on the downstream side of the transport direction X from the gap 52. It is a second support portion that supports the wire from above. According to such a configuration, the wire 21 can be suspended from above, and the wire 21 can be prevented from interfering with other members.

Further, according to the powder sintering apparatus 50 of the embodiment, the winding mechanism 22 and the winding mechanism 23 are configured so that the wire 21 can be wound. By configuring the wire 21 so that it can be wound up in this way, the position of the wire 21 in the longitudinal direction in contact with the powder material 1 can be changed according to the degree of use of the wire 21 and the like.

Further, according to the powder sintering apparatus 50 of the embodiment, the wire 21 includes a first wire 21A and a second wire 21B. The first wire 21A is arranged on one side of the powder material 1 in the width direction Y, and the second wire 21B is arranged on the other side in the width direction Y. By providing such a pair of wires 21, gaps 54 can be formed on both sides of the sintered body 2 in the width direction Y, and both ends (ends 31, 32) in the width direction Y where the density tends to be low can be formed. Can be disconnected. This makes it possible to further suppress variations in the density of the sintered body 2 after cutting.

Further, according to the powder sintering apparatus 50 of the embodiment, the diameter D2 of the wire 21 is smaller than the distance D1 of the gap 52 between the pair of rolls 11 and 12. According to such a configuration, the wire 21 can be easily and surely arranged in the gap 52 between the rolls 11 and 12.

Further, according to the powder sintering apparatus 50 of the embodiment, the diameter D2 of the wire 21 is set to 1/2 or more of the thickness D3 of the sintered body 2. According to such a setting, the gap 54 can be provided large, and the sintered body 2 can be easily cut.

Further, according to the powder sintering apparatus 50 of the embodiment, the void forming portion 301 forms a groove extending along the transport direction X on the surface of the sintered body 2 as the void 54. By forming the groove as the gap 54 in this way, the gap 54 can be easily confirmed from the outside, and cutting becomes easy.

Although the present invention has been described above with reference to the above-described embodiments, the present invention is not limited to the above-mentioned embodiments. For example, in the above embodiment, the case where the gap forming portion 301 includes the wire 21 has been described, but the case is not limited to such a case. In addition to the wire 21, any configuration may be adopted as long as a gap can be formed in the sintered body 2 along the transport direction X.

The powder sintering apparatus of the present invention is useful for a powder sintering apparatus that sinters a powder material to obtain a sintered body.

1 Powder material 2 Sintered body 11 1st roll (upper roll)
12 2nd roll (lower roll)
13 1st heating device 14 2nd heating device 21 Wire (metal wire)
21A 1st wire 21B 2nd wire 22 Winding mechanism (1st support)
23 Unwinding mechanism (second support)
24, 25 Guide rolls 31, 32 Ends 33 Central 50 Powder sintering equipment 52 Gap (proximity point)
54 Void (groove)
101 Powder transfer mechanism 201 Heating and pressurizing mechanism 301 Void forming part (groove forming mechanism)
401 Cut part (end separation mechanism)
501 Material recovery mechanism D1 Interval D2 Diameter D3 Thickness X Transport direction Y Width direction

Claims (7)

A powder transport mechanism that transports powder materials in the transport direction,
A pair of rolls facing each other with a gap, and a pair of rolls in which the powder material conveyed by the powder transfer mechanism is arranged in the gap and heated and pressed.
By partially blocking the transport path of the powder material heated and pressurized by the pair of rolls in the gap, void formation is formed in the sintered body made of the powder material along the transport direction. Department and
A powder sintering apparatus comprising a cutting portion for cutting the sintered body along the void formed by the void forming portion. The powder sintering apparatus according to claim 1, wherein the gap forming portion includes a wire that traverses the gap between the pair of rolls in the transport direction. The gap forming portion includes a first support portion that supports the wire from above on the upstream side in the transport direction from the gap, and a second support portion that supports the wire from above on the downstream side in the transport direction from the gap. The powder sintering apparatus according to claim 2, further comprising a support portion. The powder sintering apparatus according to claim 3, wherein the first support portion and the second support portion are configured so that the wire can be wound up. The wire comprises a first wire arranged on one side in the width direction of the powder material conveyed in the conveying direction and a second wire arranged on the other side in the width direction. The powder sintering apparatus according to any one of 2 to 4. The powder sintering apparatus according to any one of claims 2 to 5, wherein the diameter of the wire is smaller than the distance between the gaps of the pair of rolls. The powder sintering apparatus according to any one of claims 1 to 6, wherein the void forming portion forms a groove extending along the conveying direction on the surface of the sintered body as the void.

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