JP6379850B2 - Powder for laser sintering and method for producing structure - Google Patents

Description

The present invention relates to the production how laser sintering powder and structures.

  Manufacture is performed in which a metal powder is irradiated with laser light to form a structure. This method is suitable for high-mix low-volume production because the structure is formed by controlling laser light using a computer. This manufacturing method is disclosed in Patent Document 1. According to it, first, metal powder is spread on a flat plate. Next, the leveling plate is moved along the surface of the metal powder layer, and the metal powder is leveled and adjusted to a predetermined thickness. Subsequently, a protective gas is allowed to flow over the metal powder layer to form a protective gas atmosphere. Next, the laser beam is scanned in the form of a beam to draw a predetermined image. The metal powder is sintered and bonded at the place where the laser beam is irradiated.

  The step of spreading the metal powder, the step of leveling the metal powder, and the step of drawing by irradiating the metal powder with laser light are repeated. Thereby, the metal powder sintered in each layer is combined to form a three-dimensional structure.

Special table 2001-504897 gazette

  If the metal powder is fine, it will rise easily in the air. Therefore, the average particle size of the metal powder usable for laser sintering was 30 μm or more. When a plurality of metal powders overlap, the metal powder on the surface is easily irradiated with laser light and heated, and the shadowed metal powder is less likely to be heated. For this reason, the structure is in a state in which a completely sintered layer and an incompletely sintered layer are stacked in the stacked direction. When the fully sintered and incompletely sintered layers are interleaved, the surface appearance becomes dull. Therefore, the surface must be polished. The structure formed by laser sintering can form a fine shape, but the fine shape has a surface that cannot be reached by a polishing tool or a polishing cloth, and it is difficult to make the surface glossy. Therefore, there is a demand for a powder for laser sintering, a structure manufacturing method, and a structure manufacturing apparatus capable of manufacturing a structure having gloss on the surface in the manufacture of a structure formed by irradiating a metal powder with laser light. It was.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

[Application Example 1]
The laser sintering powder according to this application example is a laser sintering powder that is sintered by irradiation with laser light,
A plurality of metal particles having an average aspect ratio defined by the minor axis / major axis of 0.3 to 0.9 ;
A binder that binds the plurality of metal particles to each other , and includes a material that decomposes and gasifies by the laser beam ;
Have
The average particle size is 3 to 10 times the average particle size of the metal particles, and 30 to 50 μm,
The laser sintering powder includes pores at a ratio of 1% by volume to 50% by volume .

  According to this application example, the laser sintering powder has a plurality of metal particles bonded together by a binder. The size of the metal particles is smaller than that of the laser sintering powder. The laser sintering powder is disposed in a predetermined thickness. When the laser sintering powder is irradiated with laser light, the binder is decomposed and gasified, and a plurality of metal particles are separated in the laser sintering powder. The metal particles irradiated with the laser light are heated. At this time, a large energy is applied to a shallow place of the laser sintering powder, and a small energy is applied to a deep place. Since the heat capacity of the metal particles can be reduced when the metal particles are small compared to when the metal particles are large, the temperature of the metal particles can be easily increased. Therefore, since the temperature of the metal particles located in the deep place can be increased, the sintered metal can be surely sintered even in the deep place.

  In laser sintering, the process of arranging the powder for laser sintering at a predetermined thickness and the drawing with laser light are repeated. When the metal particle diameter is large and the heating of the metal particle by laser light is different in the depth direction as in the past, the layer that was completely sintered and the layer that was incompletely sintered were laminated. Become a layer. In the laser sintering powder of this application example, it is suppressed that the metal particles are heated by the laser beam in the depth direction. Therefore, the structure formed by irradiating the laser sintering powder with laser light can be a structure with less unevenness on the surface on which the metal particles are laminated. As a result, the laser-sintered structure can be made into a structure having gloss on the surface.

[Application Example 2]
In laser sintering powder according to the application example, the average particle diameter of the metal particles is characterized by at 5μm or 10μm or less.

  According to this application example, the average particle size of the powder for laser sintering is 30 μm or more and 50 μm or less. When the laser sintering powder is arranged in a predetermined thickness and drawn with laser light, the laser sintering powder having an average particle size of 30 μm or more and 50 μm or less is a powder that does not rise easily. Accordingly, the laser sintering powder can be irradiated with laser light in a state where the laser sintering powder is statically stable. In addition, since the average particle diameter of the metal particles is 5 μm or more and 10 μm or less, the heat capacity of the metal particles can be reduced and the temperature during heating can be easily increased. As a result, it is possible to sinter the metal with high quality and high quality, so that the structure can be formed with high quality.

[Application Example 3 ]
In the laser sintering powder according to the application example described above, the metal particles include any one of iron, nickel, and cobalt as a main component.

  According to this application example, since the main component of the metal particles is mainly one of iron, nickel, and cobalt, the metal obtained by sintering the laser sintering powder is iron, iron alloy, nickel, It can be any of nickel alloy, cobalt and cobalt alloy.

[Application Example 4 ]
In the laser sintering powder according to the above application example, the metal particles include iron as a main component and at least one of nickel, chromium, molybdenum, and carbon.

  According to this application example, the main component of the metal particles is iron, and further includes at least one of nickel, chromium, molybdenum, and carbon. Therefore, the metal obtained by sintering the laser sintering powder is resistant to corrosion. It can be a metal having mechanical rigidity.

[Application Example 5 ]
In the laser sintering powder according to the application example, the material that is decomposed and gasified by the laser light is polyvinyl alcohol or polyvinylpyrrolidone .

  According to this application example, the binder is PVA. Since PVA can connect metal particles, the metal particles can be connected to form a powder for laser sintering. Since PVA can be sublimated by laser irradiation, the metal obtained by sintering the powder for laser sintering can contain no binder.

[Application Example 6 ]
The structure manufacturing method according to this application example is a laser sintering powder in which a plurality of metal particles are bonded by a binder , and the average particle size is 3 to 10 times the average particle size of the metal particles. A powder layer forming step of forming a powder layer made of a laser sintering powder ,
A laser sintering step of injecting a laser beam to the powder layer to draw a predetermined pattern and gasifying the binder to sinter the metal particles;
Have
A structure in which the metal particles are sintered is formed by repeating the powder layer forming step of forming the powder layer on the drawn powder layer and the laser sintering step. .

  According to this application example, the powder layer made of the laser sintering powder is formed. Then, laser light is emitted to the powder layer, and a predetermined pattern is drawn. In the place where the laser beam is irradiated, the binder is gasified and the metal particles are sintered. In the laser sintering powder of this application example, the average particle diameter of the metal particles is finer than the average particle diameter of the laser sintering powder. As the metal particles become finer, the heat capacity becomes smaller, so the metal particles are easily sintered. Therefore, since the temperature of the metal particles located in the deep place of the powder layer can be increased, the sintered metal can be surely sintered even in the deep place. As a result, the structure formed by the method of this application example can be a structure with less unevenness on the surface on which the metal particles are laminated. As a result, the laser-sintered structure can be made into a structure having gloss on the surface.

[Application Example 7 ]
In the structure manufacturing method according to the application example, the metal particles irradiated with the laser light are heated to a temperature at which the metal particles are not melted and sintered.

  According to this application example, the metal particles are heated to a temperature at which they are sintered. When heated until the metal melts, the molten metal flows in the direction in which gravity and surface tension act. Therefore, when heated to a temperature at which the metal is sintered as compared to when heated until the metal is melted, the metal can be formed in a precisely drawn shape.

[Application Example 8 ]
The structure manufacturing method according to the application example described above further includes a powder layer pressurizing step of pressurizing the powder layer in a thickness direction.

  According to this application example, since the powder layer is crushed in the thickness direction to achieve consolidation, even if the metal particles are sintered, the difference in thickness between the sintered layer and the powder layer is sufficiently increased. When a new powder layer is formed thereon, a powder layer having a uniform thickness can be formed regardless of the condition of the base. Therefore, even when the volume of the powder layer is greatly contracted with the sintering of the metal particles, it is possible to suppress the shape of the manufactured structure from greatly deviating from the design value. The dimensional accuracy can be further increased.

[Application Example 9 ]
The structure manufacturing method according to the application example described above further includes a metal particle manufacturing step of manufacturing the metal particles by an atomizing method.

[Application Example 10]
In the manufacturing method of the structure according to the application example, a granulated particle manufacturing process is provided after the metal particle manufacturing process, and granulates the metal particles by a spray drying method to manufacture the powder for laser sintering. It is characterized by having.

It is a schematic perspective view which shows the structure of the powder for laser sintering. It is a schematic diagram for demonstrating sintering of the powder for laser sintering. It is a schematic diagram which shows the structure of the spray-drying apparatus which manufactures the powder for laser sintering. It is a schematic diagram which shows the structure of the laser sintering apparatus to which 1st Embodiment of the manufacturing apparatus of the structure of this invention is applied. It is a schematic diagram for demonstrating the method (1st Embodiment of the manufacturing method of the structure of this invention) of forming a structure using the powder for laser sintering. It is a schematic diagram for demonstrating the method (1st Embodiment of the manufacturing method of the structure of this invention) of forming a structure using the powder for laser sintering. It is a schematic diagram which shows the structure of the laser sintering apparatus to which 2nd Embodiment and 3rd Embodiment of the manufacturing apparatus of the structure of this invention are applied. It is a schematic diagram for demonstrating the method (2nd Embodiment of the manufacturing method of the structure of this invention) which forms a structure using the powder for laser sintering. It is a schematic diagram for demonstrating the method (2nd Embodiment of the manufacturing method of the structure of this invention) which forms a structure using the powder for laser sintering. It is a schematic diagram for demonstrating the method (3rd Embodiment of the manufacturing method of the structure of this invention) which forms a structure using the powder for laser sintering. It is a schematic diagram for demonstrating the method (3rd Embodiment of the manufacturing method of the structure of this invention) which forms a structure using the powder for laser sintering. It is a figure which shows the Example which sintered the metal particle containing iron, nickel, and chromium. It is a figure which shows the Example which sintered the metal particle containing iron, nickel, and chromium. It is a figure which shows the Example which sintered each kind of metal particle which has iron as a main body. It is a figure which shows the Example which sintered each kind of metal particle which has iron as a main body. It is a figure which shows the Example which sintered each kind of metal particle which has iron as a main body. It is a figure which shows the Example which sintered each kind of metal particle which has cobalt as a main body. It is a figure which shows the Example which sintered each kind of metal particle which has cobalt as a main body. It is a figure which shows the Example which sintered each kind of metal particle which has nickel as a main. It is a figure which shows the Example which sintered each kind of metal particle which has nickel as a main. It is a figure which shows the Example which sintered the metal particle of SUS316L. It is a figure which shows the Example which added and sintered the powder layer pressurization process performed before a laser sintering process (exposure) using the metal particle of SUS316L. It is a figure which shows the Example which added and sintered the powder layer pressurization process performed after a laser sintering process (exposure) using the metal particle of SUS316L. It is a figure which shows the Example which used the powder particle | grain pressurization process and sintered by using the spray-drying method or the rolling granulation method as a granulation method using the metal particle of SUS316L.

  Hereinafter, the laser sintering powder, the structure manufacturing method, and the structure manufacturing apparatus of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings. That is, in this embodiment, the characteristic laser sintering powder, the manufacture of the laser sintering powder, the example of manufacturing the structure using the laser sintering powder, and the structure using the laser sintering powder The example of the apparatus which manufactures is demonstrated according to FIGS. In addition, in order to make each member in each drawing into a size that can be recognized on each drawing, the members are illustrated with different scales.

[Laser sintering powder]
First, an embodiment of the powder for laser sintering of the present invention will be described with reference to FIG. FIG. 1 is a schematic perspective view showing the structure of a laser sintering powder. As shown in FIG. 1, the laser sintering powder 1 is configured by connecting a plurality of metal particles 2.

  The average particle size of the metal particles 2 (particle size at 50% accumulation in the mass-based cumulative particle size distribution) is not particularly limited, but is preferably 5 μm or more and 10 μm or less. The finer the particle size, the finer the surface roughness of the manufactured structure. If the average particle size is less than the lower limit, depending on the constituent material of the metal particles 2, the metal particles 2 are likely to float in the air, which may make it difficult to handle the metal particles 2. If the average particle size exceeds the upper limit, depending on the constituent material of the metal particles 2, the sinterability of the metal particles 2 may be reduced, and it may take a long time to manufacture the structure. The average particle size of the metal powder and the average particle size of the granulated powder are various, such as a dynamic light scattering method, a laser diffraction method, a centrifugal sedimentation method, a FFF (Field Fow Fractionation) method, and an electrical detector method. It can be measured by a particle size measuring method.

  Although the constituent material of the metal particle 2 will not be specifically limited if it is a metal material, Preferably, the powder manufactured by the atomizing method which has any one of iron, nickel, and cobalt as a main component is included. Thereby, the metal which sintered the powder 1 for laser sintering can be made into either iron, an iron alloy, nickel, a nickel alloy, cobalt, and a cobalt alloy. And when the metal particle 2 is a particle | grains which have iron as a main component, it is preferable that the metal particle 2 contains any one element in nickel, chromium, molybdenum, and carbon, or some combination. Moreover, when the metal particle 2 is a particle having nickel as a main component, the metal particle 2 preferably contains any one element or a combination of chromium, molybdenum, and carbon. Thereby, the metal which sintered the powder 1 for laser sintering can be made into a metal which has corrosion resistance and mechanical rigidity.

  In addition, the atomizing method includes a water atomizing method, a gas atomizing method, a high-speed rotating water stream atomizing method, and the like, and the metal particles 2 may be manufactured by any of them.

  The shape of the metal particle 2 is not particularly limited, and may be a spherical shape such as a true sphere or an elliptical sphere, a polyhedron such as a cube or a rectangular parallelepiped, and a columnar body such as a cylinder or a prism. It may be a cone such as a cone or a pyramid, or may have other irregular shapes.

  However, as will be described in detail later, when the step of pressing the powder layer formed using the laser sintering powder 1 in the thickness direction is performed, the aspect ratio of the metal particles 2 is within a predetermined range. It is preferable. Specifically, when the minor axis of the metal particle 2 is S [μm] and the major axis is L [μm], the average aspect ratio defined by S / L is 0.3 or more and 0.9 or less. It is preferable that it is 0.4 or more and 0.8 or less. The metal particles 2 having such an aspect ratio have a certain anisotropy in shape. For this reason, when the metal particles 2 are fixed to each other via the binder 3, the metal particles 2 are easily caught with each other, and the property of maintaining the fixed state is easily developed. When a powder layer manufactured using the laser sintering powder 1 is subjected to a step of pressing in the thickness direction, a certain frictional resistance can be secured between the metal particles 2, so that the pressure is increased. It is possible to prevent the powder layer from collapsing at once. Therefore, it contributes to ensuring the shape retention of the powder layer after pressing.

  The major axis is the maximum length that can be taken in the projected image of the metal particles 2, and the minor axis is the maximum length that can be taken in the direction orthogonal to the maximum length. The average value of the aspect ratio is obtained as the average value of the aspect ratio values measured for 100 or more metal particles 2.

  From the viewpoint of frictional resistance between the metal particles 2, the atomizing method for producing the metal particles 2 includes a water atomizing method using a liquid as a medium for pulverizing molten metal or a high-speed rotating water atomizing method. Is preferably used. Since all these atomization methods use water as a medium for pulverizing molten metal, the collision energy when pulverizing molten metal is large, and the cooling rate for cooling the pulverized molten metal is also large. . For this reason, compared with the method of using gas as a medium for pulverizing molten metal, such as the gas atomization method, fine irregularities are easily formed on the surface of the metal particle 2 to be manufactured. The frictional resistance can be relatively increased.

  The surface of the metal particle 2 is covered with a binder 3. The metal particles 2 are fixed by the binder 3. The material of the binder 3 may be any material that can be easily gasified by sublimation or decomposition by heating, and various resin materials can be used. For example, PVA (polyvinyl alcohol), PVP (polyvinyl pyrrolidone), or the like can be used as the material of the binder 3. In this embodiment, for example, PVA is used as the material of the binder 3. The amount of the binder is appropriately adjusted depending on the type of metal particles and the like, and is, for example, a ratio of 0.1 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the metal particles.

  In addition to the material which is easily sublimated or decomposed by heating and easily gasified, the binder 3 may contain a material which does not gasify as long as it does not inhibit the sintering of the metal particles 2. In that case, it is preferable that the material which does not gasify is 10 mass% or less of the binder 3, and it is more preferable that it is 5 mass% or less.

  Further, the binder 3 may include a plurality of materials that are easily sublimated or decomposed by heating and are easily gasified, and have different sublimation temperatures or decomposition temperatures. By including such plural kinds of materials, when the binder 3 is heated, the plural kinds of materials are sequentially sublimated or decomposed with a certain time difference. For this reason, in the process of heating the binder 3, the time during which the binder 3 is present without being gasified can be ensured longer, and accordingly, the time during which the metal particles 2 are fixed to each other can be ensured longer. Can do. As a result, when the powder layer is formed using the laser sintering powder 1 as will be described later, the shape retention can be further increased, and the dimensional accuracy of the finally manufactured structure can be further increased. Can do.

  For example, when the binder 3 contains two types of materials having different sublimation temperatures or decomposition temperatures, the temperature difference between the sublimation temperatures or the decomposition temperatures is preferably 3 degrees or more and 100 degrees or less. More preferably, it is not less than 70 degrees and not more than 70 degrees. By setting the temperature difference between the sublimation temperature or the decomposition temperature within the above range, the shape retention of the powder layer can be sufficiently enhanced.

  The average particle size of the laser sintering powder 1 (50% cumulative particle size in the mass-based cumulative particle size distribution) is not particularly limited, but is preferably 30 μm or more and 50 μm or less. Furthermore, it is preferably 30 μm or more and 40 μm or less. When the average particle size of the laser sintering powder 1 is smaller than the lower limit value, the laser sintering powder 1 rises when the laser beam is irradiated, so that it is difficult to form a structure. When the average particle diameter of the laser sintering powder 1 is larger than the above upper limit, the voids between the laser sintering powder 1 become large, so that there is a high possibility that bubbles are formed in the structure.

  On the other hand, the average particle size of the powder 1 for laser sintering is preferably 3 to 10 times the average particle size of the metal particles 2. By setting the average particle diameter of the laser sintering powder 1 within the above range, the balance of the particle diameters of the laser sintering powder 1 and the metal particles 2 is optimized. Both fluidity and sinterability of the metal particles 2 can be achieved. In addition, as will be described in detail later, when a powder layer formed using the laser sintering powder 1 is pressed in the thickness direction, the laser sintering powder 1 is moderately easily broken down, and metal particles 2 becomes easy to be rearranged more densely. Therefore, volume shrinkage when the metal particles 2 are sintered can be further reduced.

  In the figure, in order to make the laser sintering powder 1 easy to understand, three laser sintering powders 1 are shown separately. When the laser sintering powder 1 is used, a large number of laser sintering powders 1 are stacked and spread.

  FIG. 2 is a schematic diagram for explaining the sintering of the laser sintering powder. As shown in FIG. 2 (a), a large number of powders 1 for laser sintering are stacked and spread. In the drawing, three layers of the laser sintering powder 1 are arranged to be stacked, but the number of layers of the laser sintering powder 1 to be laminated is not particularly limited. In order to arrange the array of the metal particles 2 after sintering with good quality, it is preferable to arrange the laser sintering powder 1 in one layer.

  Next, as shown in FIG. 2B, the laser sintering powder 1 is irradiated with laser light 4. The binder 3 is heated by the laser beam 4 and sublimates. Since the binding force of the metal particles 2 by the binder 3 is reduced, the metal particles 2 are easily moved. As shown in FIG. 2 (c), the metal particles 2 are heated to further increase the fluidity. And the metal particle 2 moves so that the clearance gap between the powder 1 for laser sintering may be filled. As a result, the metal particles 2 are aligned as shown in FIG. Each of the metal particles 2 approaches and heats up with the adjacent metal particle 2 to be metal-bonded. When the irradiation with the laser beam 4 is stopped, the arrangement of the metal particles 2 is cooled. At this time, since the metal particle 2 is metal-bonded, it is a lump of metal. And since the metal particle 2 has arranged densely as shown in FIG.2 (e), the formed structure can also be made into the glossy surface also in the side surface of the left-right side in a figure.

  FIG. 3 is a schematic view showing the structure of a spray drying apparatus for producing laser sintering powder. As shown in FIG. 3, the spray drying device 5 includes a first container 6. In the first container 6, a disk rotating unit 7, a raw material dropping unit 8, and a hot air blowing unit 9 are installed on a ceiling 6 a. The disc rotating unit 7 includes a motor 10, and a conical rotating plate 11 is installed on a rotating shaft 10 a of the motor 10. The rotating plate 11 is rotated by the motor 10.

  The raw material dropping unit 8 includes a second container 12. The second container 12 is charged with metal particles 2, a binder 3, and a solvent 13 for dissolving the binder 3. The solvent 13 is not particularly limited as long as it is a medium that dissolves the binder 3 and has a low viscosity and can be easily dried. As the solvent 13, for example, water, methyl alcohol, ethyl alcohol, MEK (methyl ethyl ketone), or the like can be used. In this embodiment, for example, water is used as the solvent 13. The material of the metal particle 2 is adjusted according to the composition of the structure. For example, when the material of the structure is stainless steel SUS301, the metal particles 2 are an alloy containing iron, chromium and nickel.

  The raw material dropping unit 8 includes a motor 14 on the ceiling 6 a side, and an impeller 15 is installed on a rotating shaft 14 a of the motor 14. The impeller 15 is rotated by a motor 14. The impeller 15 has a function of stirring the metal particles 2, the binder 3 and the solvent 13. The metal particles 2 are evenly dispersed in the solvent 13 by the impeller 15 and the binder 3 is evenly dissolved.

  A discharge port 16 is disposed on the lower side of the second container 12 in the figure. A droplet 17 composed of the metal particle 2, the binder 3 and the solvent 13 is dropped from the discharge port 16. An electromagnetic valve 16 a is installed at the discharge port 16, and the electromagnetic valve 16 a can adjust the size and the discharge frequency of the droplet 17.

  The hot air blowing unit 9 includes a motor 18 on the ceiling 6 a side, and an impeller 21 is installed on a rotating shaft 18 a of the motor 18. The impeller 21 is rotated by the motor 18. A heater 22 is installed between the motor 18 and the impeller 21. The heater 22 heats the airflow that flows around the heater 22. Thereby, the hot air blowing unit 9 causes the hot air 23 to flow downward in the drawing.

  Gravity acts on the droplet 17 discharged from the discharge port 16. A rotating plate 11 that rotates in the direction of gravitational acceleration of the discharge port 16 is located. The droplet 17 hits the rotating plate 11 and is divided into minute droplets 24. The micro droplet 24 travels in the air. Hot air 23 flows around the rotating plate 11. The solvent 13 of the microdroplet 24 is heated by the hot air 23 and released into the air. Thereby, the microdroplets 24 are dried to become the laser sintering powder 1. The dried laser sintering powder 1 moves to the lower side in the figure due to gravity and accumulates. The laser sintering powder 1 is manufactured by the above procedure.

  The laser sintering powder 1 thus produced contains a large number of particles (granulated particles) having pores therein. Such particles having vacancies in the inner part are relatively densified in the outer shell portion and have a relatively high mechanical strength as compared with particles having no vacancies inside. For this reason, the powder 1 for laser sintering containing the particle | grains which have a void | hole in such an inside becomes the thing excellent in fluidity | liquidity. Moreover, since it has a void | hole inside, when pressing the powder layer formed using the powder 1 for laser sintering in the thickness direction so that it may explain in full detail later, a particle | grain tends to collapse. It is easy to compress the powder layer. For this reason, a powder layer can be pressurized more uniformly in a pressurization process. Therefore, by including particles having pores in the inside, the laser sintering powder 1 achieves both fluidity and easy compressibility.

  As described above, the metal particles 2 having the aspect ratio in the range as described above ensure a certain frictional resistance between the metal particles 2. It can be formed quickly, and the formed outer shell portion is easily densified. For this reason, the metal particles 2 having an aspect ratio in the range as described above are useful in forming particles having pores therein.

  The size of the pores contained in the interior is not particularly limited, but is preferably about 1% to 50% by volume of the laser sintering powder 1 and preferably about 5% to 30% by volume. Is more preferable. By setting the size of the pores within such a range, the powder 1 for laser sintering can particularly achieve both fluidity and easy compression. That is, if the pore size is below the lower limit, easy compressibility may be reduced, and if the pore size exceeds the upper limit, the mechanical strength of the outer shell portion is reduced and the fluidity is decreased. May decrease.

  The method for producing the laser sintering powder 1 is not limited to the spray drying method described above, and may be various granulation methods such as a rolling granulation method, a fluidized granulation method, and a rolling fluidized granulation method. May be. However, according to the spray drying method, the powder 1 for laser sintering containing a large number of particles having pores inside as described above (preferably 30% or more by number ratio) can be obtained.

  Further, the laser sintering powder 1 may be a mixed powder obtained by mixing an arbitrary powder with the granulated powder produced as described above. As long as arbitrary powder does not inhibit sintering of the metal particle 2, the constituent material and the amount of mixing are not specifically limited.

[Structure manufacturing equipment]
Next, a laser sintering apparatus to which the first embodiment of the structure manufacturing apparatus of the present invention is applied will be described.

  FIG. 4 is a schematic diagram showing the structure of a laser sintering apparatus to which the first embodiment of the structure manufacturing apparatus of the present invention is applied. The laser sintering apparatus 25 includes an XYZ stage 26. The XYZ stage 26 is a device that moves the table 27 in three orthogonal directions. Specifically, the XYZ stage 26 includes an XY stage 28 and a lifting device 29. The XY stage 28 moves the table 27 in the horizontal direction. The lifting device 29 is provided on the XY stage 28 and lifts and lowers the table 27. The XY stage 28 includes a biaxial linear motion mechanism, and the lifting device 29 includes a uniaxial linear motion mechanism. As a result, the XYZ stage 26 can move the table 27 in three orthogonal directions.

  A bottomed rectangular tube-shaped container 30 is installed on the table 27, and the laser sintering powder 1 is spread in the container 30. A powder supply device 31 for supplying the laser sintering powder 1 into the container 30 is installed on the upper side of the container 30 in the figure. The powder supply device 31 includes a rail 32 extending to the left and right in the drawing. A moving stage 33 that moves along the rail 32 is installed. The moving stage 33 is provided with a hopper 34 for storing the laser sintering powder 1. The appearance of the hopper 34 has a triangular prism shape, and a discharge port 34 a is provided on the side facing the bottom 30 a of the container 30.

  An electromagnetic valve 35 is installed at the discharge port 34a, and the electromagnetic valve 35 opens and closes the discharge port 34a. When the electromagnetic valve 35 opens the discharge port 34 a, the laser sintering powder 1 flows from the discharge port 34 a toward the bottom 30 a of the container 30. A leveling plate 36 is installed at the discharge port 34a. The leveling plate 36 is also referred to as a squeegee. The electromagnetic valve 35 opens the discharge port 34a, and the moving stage 33 moves the hopper 34 and the leveling plate 36. Thereby, the powder 1 for laser sintering is supplied to the bottom 30a, and the leveling plate 36 can level the surface of the powder 1 for laser sintering flat. Note that instead of the leveling plate 36, a mechanism in which a cylindrical roller moves while rotating may be installed. And you may level the surface of the powder 1 for laser sintering by rotating a roller. The moving stage 33, the hopper 34, the leveling plate 36, and the like as described above constitute a powder layer forming unit of the laser sintering apparatus 25.

  A laser irradiation unit 37 is installed on the upper side of the powder supply device 31 in the drawing. The laser irradiation unit 37 includes a laser light source 38. The laser light source 38 only needs to emit a laser beam 4 having a light intensity capable of sintering the metal particles 2, and a laser light source such as a carbon dioxide gas laser, an argon laser, a YAG (Yttrium Aluminum Garnet) laser, or the like can be used. In the present embodiment, for example, a carbon dioxide laser is used for the laser light source 38.

  The laser light 4 emitted from the laser light source 38 enters the scanner 41. The scanner 41 includes a mirror 41a, and the scanner 41 swings the mirror 41a. The laser beam 4 incident on the scanner 41 is reflected by the mirror 41a. Then, since the mirror 41a swings, the laser light 4 is scanned by the scanner 41.

  The laser beam 4 reflected by the mirror 41a enters the condenser lens. The condensing lens 42 is a cylindrical lens, and condenses the scanned laser light 4 on the surface of the laser sintering powder 1. The condenser lens 42 may be a single lens or a combination lens.

  A hot air blowing unit 43 is installed on the right side of the laser irradiation unit 37 in the drawing. The hot air blowing unit 43 includes a heater and heats the gas. The hot air blowing unit 43 includes a motor and an impeller, and the motor rotates the impeller to blow air. The hot air blower 43 includes a blower pipe 44 on the container 30 side. The blower pipes 44 are provided with jet outlets 44a at equal intervals. The hot air blower 43 blows the hot air 23 to the blower pipe 44. Then, the hot air 23 is blown toward the laser sintering powder 1 from the outlet 44 a of the blower tube 44.

  The laser sintering apparatus 25 includes a control unit 45. The control unit 45 is electrically or optically connected to the XYZ stage 26, the moving stage 33, the electromagnetic valve 35, the laser light source 38, and the hot air blowing unit 43. And the control part 45 controls each apparatus, and forms a structure from the powder 1 for laser sintering.

  The laser sintering device 25 includes a chamber 46, and an XYZ stage 26, a container 30, a powder supply device 31, a laser irradiation unit 37, and a hot air blowing unit 43 are disposed in the chamber 46. An inert gas supply unit 48 for supplying an inert gas 47 is installed on the chamber 46. The interior of the chamber 46 is filled with an inert gas 47. The type of the inert gas 47 is not particularly limited, but in this embodiment, for example, argon gas is used as the inert gas 47. That is, the hot air 23 blown from the hot air blowing unit 43 is made of heated argon gas. Further, nitrogen gas may be used as the inert gas 47. Thereby, it can prevent that the metal particle 2 oxidizes.

[Method of manufacturing structure]
<< First Embodiment >>
Next, 1st Embodiment of the manufacturing method of the structure of this invention is described.

  FIG. 5 and FIG. 6 are schematic diagrams for explaining a method of forming a structure using a laser sintering powder (first embodiment of the method for producing a structure of the present invention). Hereinafter, a method for forming a structure will be described with reference to FIGS. 5 and 6. In this method, the laser sintering apparatus 25 described above is used.

  As shown in FIG. 5A, the laser sintering powder 1 is placed in the hopper 34 of the laser sintering apparatus 25. At this time, the electromagnetic valve 35 is closed to close the discharge port 34a. Thereby, the laser sintering powder 1 is held in the hopper 34. And the space | interval of the bottom 30a of the container 30 and the leveling board 36 is made into the average particle diameter of the powder 1 for laser sintering. Next, as shown in FIG. 5B, the electromagnetic valve 35 is opened to open the discharge port 34a. Thereby, the powder 1 for laser sintering is supplied to the bottom 30a of the container 30 from the discharge port 34a. The moving stage 33 moves the hopper 34 and the leveling plate 36 while the discharge port 34a is opened. Thereby, the powder 1 for laser sintering is supplied to the bottom 30a. Then, the laser sintering powder 1 is sequentially spread on the bottom 30a of the container 30, and the surface of the laser sintering powder 1 is leveled. Thereby, the 1st powder layer 1a of the powder 1 for laser sintering is formed. That is, the first powder layer 1a is formed by the powder layer forming means including the moving stage 33, the hopper 34, the leveling plate 36, and the like. The thickness of the first powder layer 1a may be different from the average particle diameter of the laser sintering powder 1, but is preferably set to the same length as the average particle diameter. Thereby, the powder 1 for laser sintering is spread | laid so that it may not overlap in the thickness direction in the 1st powder layer 1a. Next, the electromagnetic valve 35 is closed to close the discharge port 34a, so that the laser sintering powder 1 does not flow out of the discharge port 34a.

  Next, as shown in FIG. 5C, the hot air 23 flows toward the first powder layer 1a. Thereby, the first powder layer 1a is heated. The temperature of the first powder layer 1a to be heated is lower than the temperature at which the metal particles 2 are sintered. Next, the laser beam 4 is irradiated so as to be focused on the first powder layer 1a. The laser light is scanned by the scanner 41 and the first powder layer 1 a is moved in the horizontal direction by the XY stage 28. Thus, a predetermined pattern is drawn on the first powder layer 1a.

  The laser sintering powder 1 irradiated with laser light is sintered at a temperature that does not melt. If the metal is heated until it melts, the molten metal flows in the direction in which gravity or surface tension acts. Therefore, it is not heated until the metal is melted, but is heated at a temperature at which it is sintered, so that a metal structure can be formed in a shape drawn with high accuracy.

  As a result, as shown in FIG. 5D, a sintered layer 1b in which the metal particles 2 are sintered is formed in the first powder layer 1a where the laser beam 4 is irradiated. Thereafter, the container 30 is lowered by the lifting device 29. The distance between the sintered layer 1b and the leveling plate 36 is set to the average particle diameter of the laser sintering powder 1.

  Next, as shown in FIG. 5E, the hopper 34 and the leveling plate 36 are moved to the left in the drawing by the moving stage 33. When the laser sintering powder 1 in the hopper 34 is reduced, it is replenished at this time. Next, as shown in FIG. 5 (f), the electromagnetic valve 35 is opened to open the discharge port 34a. Thereby, the powder 1 for laser sintering is supplied from the discharge port 34a so as to overlap the first powder layer 1a and the sintered layer 1b. The hopper 34 and the leveling plate 36 are moved by the moving stage 33 while the discharge port 34a is opened. As a result, the laser sintering powder 1 is supplied to the bottom 30a and the laser sintering powder 1 is sequentially spread on the bottom 30a of the container 30, and the surface of the laser sintering powder 1 is leveled. Thus, the second powder layer 1a of the laser sintering powder 1 is formed so as to overlap the first powder layer 1a and the sintered layer 1b. Also in this case, the thickness of the second powder layer 1a may be different from the average particle diameter of the laser sintering powder 1, but is preferably set to the same length as the average particle diameter. Thereby, in the second powder layer 1a, the laser sintering powder 1 is spread so as not to overlap in the thickness direction. Next, the electromagnetic valve 35 is closed to close the discharge port 34a, so that the laser sintering powder 1 does not flow out of the discharge port 34a.

  Next, as shown in FIG. 6A, hot air 23 flows toward the second powder layer 1a. Thereby, the second powder layer 1a is heated. Next, the laser beam 4 is irradiated so as to be focused on the uppermost (second) powder layer 1a. The laser beam 4 is scanned by the scanner 41, and the second powder layer 1a is moved in the horizontal direction by the XY stage 28. Thereby, a predetermined pattern is drawn on the second powder layer 1a. As a result, as shown in FIG. 6B, a sintered layer 1b in which the metal particles 2 are sintered is formed in the second powder layer 1a where the laser beam 4 is irradiated. The sintered layer 1b is formed in connection with the underlying sintered layer 1b. Then, the container 30 is lowered by the lifting device 29. And the space | interval of the sintered layer 1b and the equalizing board 36 is set to the same length as the average particle diameter of the powder 1 for laser sintering. At this time, the distance between the sintered layer 1b and the leveling plate 36 may be different from the average particle diameter of the powder 1 for laser sintering.

  Thereafter, the step of forming the powder layer 1a so as to overlap with the drawn and formed sintered layer 1b and the step of emitting the laser beam 4 toward the powder layer 1a are repeated. As a result, as shown in FIG. 6C, the container 30 is formed with a structure 49 in which a large number of sintered layers 1b sintered in a predetermined pattern are laminated. Then, as shown in FIG. 6D, the structure 49 is completed by removing the powder 49 for laser sintering attached to the structure 49 by removing the structure 49 from the container 30.

  The structure 49 manufactured using the above manufacturing method can be used for various applications. For example, it can use for the metal piece with which a tooth | gear is used for orthodontics of a human body. Since this metal piece is designed according to the shape of the tooth to be installed, it is a component with many types. Also at this time, the structure 49 can be manufactured in accordance with the required shape.

  In addition, the structure 49 includes electronic parts such as automobile parts, railway vehicle parts, ship parts, aircraft parts, personal computer parts, mobile phone terminal parts, etc. It can be applied to all structural parts such as machine parts, machine tools, machine parts such as semiconductor manufacturing equipment.

<< Second Embodiment >>
Next, 2nd Embodiment of the manufacturing method of the structure of this invention is described.

  Hereinafter, although 2nd Embodiment is described, in the following description, it demonstrates centering around difference with 1st Embodiment, The description is abbreviate | omitted about the same matter. Moreover, in the figure, the same code | symbol is attached | subjected about the matter similar to embodiment mentioned above.

  FIG. 8 and FIG. 9 are schematic diagrams for explaining a method of forming a structure using a laser sintering powder (second embodiment of the method for producing a structure of the present invention). Hereinafter, a method of forming a structure will be described with reference to FIGS. In this method, a laser sintering apparatus 25 (second embodiment of the structure manufacturing apparatus of the present invention) shown in FIG. 7 is used.

  First, the laser sintering apparatus 25 shown in FIG. 7 will be described. In FIG. 7, only a portion near the rail 32 is extracted from the laser sintering apparatus 25 and illustrated.

  The laser sintering apparatus 25 shown in FIG. 7 is the same as the laser sintering apparatus 25 shown in FIG. 4 except that pressure means for pressing the powder layer 1a in the thickness direction is added.

  That is, the laser sintering apparatus 25 shown in FIG. 7 is installed on a moving stage 33 that moves along a rail 32, and is a pressurizing mechanism (pressurizing means) capable of pressurizing in the thickness direction in contact with the powder layer 1a. 39 is further provided. When the moving stage 33 moves along the rail 32, the pressurizing mechanism 39 can be moved accordingly.

  The pressurizing mechanism 39 is capable of moving a rotation shaft 391 parallel to the surface of the powder layer 1a, a roller 392 rotatably provided around the rotation shaft 391, and the rotation shaft 391 and the roller 392 in the vertical direction of FIG. An elevating device 393. Since the roller 392 is less likely to inadvertently scrape the powder layer 1a, it is easy to crush the powder layer 1a to a target thickness. Further, since the structure is simple and small, even if it is installed on the moving stage 33, it is difficult to hinder the driving of the moving stage 33.

  In addition, the part which contacts the powder layer 1a among the rollers 392 may be comprised with the material which prevents adhesion with the powder layer 1a as needed. Furthermore, the part which contacts the powder layer 1a may be subjected to a material surface treatment for preventing the adhesion of the powder layer 1a, or may be formed with an adhesion preventing layer, as necessary.

  Further, the pressurizing mechanism 39 is electrically or optically connected to the control unit 45 via a wiring (not shown). Thereby, the operation of the pressurizing mechanism 39 can be controlled by the control unit 45.

  In addition, the structure of the pressurization mechanism 39 is not limited to what was mentioned above, For example, it replaces with the roller 392 and the arbitrary which can pressurize the powder layer 1a in the thickness direction, such as a flat plate which compresses the powder layer 1a in the thickness direction The following means can be used.

Next, a method for forming the structure shown in FIGS. 8 and 9 will be described.
First, as shown in FIG. 8A, the laser sintering powder 1 is placed in the hopper 34 of the laser sintering apparatus 25. Next, the laser sintering powder 1 is supplied from the discharge port 34 a to the bottom 30 a of the container 30. As the moving stage 33 moves, the surface of the supplied powder 1 for laser sintering is leveled, so that a first powder layer 1a having a substantially constant thickness is formed as shown in FIG. 8B. (Powder layer forming step).

  Next, the surface of the first powder layer 1a whose surface is leveled is pressed in the thickness direction by the pressing mechanism 39 (powder layer pressing step). As a result, the first powder layer 1a is crushed in the thickness direction as shown in FIG. 8C, the volume contracts, and consolidation is achieved. That is, by moving the roller 392 along the surface of the first powder layer 1 a while rotating the roller 392, the first powder layer 1 a is crushed in the thickness direction by the roller 392. At this time, the degree of consolidation can be controlled by appropriately adjusting the distance between the bottom 30a of the container 30 and the roller 392 by the lifting device 393. In addition, as a standard of the degree of consolidation, for example, when the metal particles 2 are sintered to form the sintered layer 1b, the first powder layer is set to have the same thickness as the sintered layer 1b. An example in which 1a is consolidated is given.

  Next, as shown in FIG. 8D, hot air 23 flows toward the first powder layer 1a. Thereby, the first powder layer 1a is heated. Next, the laser beam 4 is irradiated so as to be focused on the first powder layer 1a (laser sintering step). Thus, a predetermined pattern is drawn on the first powder layer 1a. As a result, as shown in FIG. 8E, a sintered layer 1b in which the metal particles 2 are sintered is formed in the first powder layer 1a where the laser beam 4 is irradiated.

  Next, as shown in FIG. 8F, the second powder layer 1a of the laser sintering powder 1 is formed so as to overlap the first powder layer 1a and the sintered layer 1b (see FIG. 8F). Powder layer forming step).

  Next, the surface of the second powder layer 1a whose surface is leveled is pressed in the thickness direction by the pressing mechanism 39 (powder layer pressing step). As a result, the second powder layer 1a is crushed in the thickness direction as shown in FIG. 9A, the volume shrinks, and consolidation is achieved. Also in this case, as a measure of the degree of consolidation, when the metal particles 2 are sintered to form the sintered layer 1b, the second powder layer is formed so as to have the same thickness as the sintered layer 1b. An example in which 1a is consolidated is given.

  Next, as shown in FIG. 9B, hot air 23 flows toward the second powder layer 1a. Thereby, the second powder layer 1a is heated. Next, the laser beam 4 is irradiated so as to be focused on the second powder layer 1a (laser sintering step). Thereby, a predetermined pattern is drawn on the second powder layer 1a. As a result, as shown in FIG. 9C, a sintered layer 1b in which the metal particles 2 are sintered is formed in the second powder layer 1a where the laser beam 4 is irradiated.

  Thereafter, the step of forming the powder layer 1a so as to overlap the drawn and formed sintered layer 1b, the step of pressing the powder layer 1a in the thickness direction, and the laser beam 4 is emitted toward the powder layer 1a. The steps are repeated in this order. As a result, as shown in FIG. 9D, the container 30 is formed with a structure 49 in which a large number of sintered layers 1b sintered in a predetermined pattern are laminated. Then, as shown in FIG. 9 (e), the structure 49 is completed by removing the powder 49 for laser sintering attached to the structure 49 by taking the structure 49 from the container 30.

  In the structure 49 obtained by the above forming method, since each powder layer 1a is pressurized, when the laser beam 4 is irradiated to the powder layer 1a and the metal particles 2 are sintered, the sintering is performed. The volume shrinkage associated with is kept to a minimum.

  Specifically, when the metal particles 2 are sintered in a state where the powder layer 1a is not pressurized, depending on the particle diameter of the powder 1 for laser sintering or the particle diameter of the metal particles 2, the metal particles 2 may be sintered. Along with this, the volume of the powder layer 1a in that portion may shrink relatively large. When such a large shrinkage occurs, a large difference in volume occurs between the sintered layer 1b formed along with the sintering of the metal particles 2 and the powder layer 1a adjacent to the sintered layer 1b. And the powder layer 1a have different thicknesses. Then, when the step of forming the powder layer 1a and the step of emitting the laser beam 4 are repeated, the difference in thickness is accumulated, and when the new powder layer 1a is formed, the condition of the base, that is, Depending on whether the ground is the powder layer 1a or the sintered layer 1b, the thickness of the new powder layer 1a to be formed may be different. As a result, the thickness of the new powder layer 1a becomes non-uniform, and it becomes difficult to manufacture the structure 49 having the target shape. Moreover, if the volume of the powder layer 1a of the part shrink | contracts greatly with the sintering of the metal particle 2, there exists a possibility that irradiation of the laser beam 4 may become difficult by the part hidden behind the powder layer 1a which is not shrunk by it. is there.

  On the other hand, the room of volume shrinkage accompanying the sintering of the metal particles 2 can be crushed beforehand by adding a step of pressing the powder layer 1a in the thickness direction as in this embodiment. Thereby, even if the metal particle 2 sinters, the volume shrinkage accompanying it can be kept to the minimum. As a result, the difference in thickness between the sintered layer 1b and the powder layer 1a can be made sufficiently small, and when forming a new powder layer 1a, a powder having a uniform thickness regardless of the underlying conditions. Layer 1a can be formed. Moreover, since the shrinkage | contraction accompanying sintering of the metal particle 2 can be made small enough, it can prevent that irradiation of the laser beam 4 is inhibited by the powder layer 1a.

  Therefore, according to the present embodiment, even when the volume of the powder layer 1a is greatly contracted as the metal particles 2 are sintered, the shape of the structure 49 to be manufactured deviates greatly from the design value. And the dimensional accuracy of the structure 49 can be further increased.

  In the second embodiment as described above, the same operations and effects as in the first embodiment can be obtained.

«Third embodiment»
Next, a third embodiment of the structure manufacturing method of the present invention will be described.

  Hereinafter, the third embodiment will be described. However, in the following description, differences from the second embodiment will be mainly described, and description of similar matters will be omitted. Moreover, in the figure, the same code | symbol is attached | subjected about the matter similar to embodiment mentioned above.

  FIG. 10 and FIG. 11 are schematic views for explaining a method of forming a structure using a laser sintering powder (third embodiment of the method of manufacturing a structure of the present invention). Hereinafter, a method for forming a structure will be described with reference to FIGS. 10 and 11. Also in this method, the laser sintering apparatus 25 shown in FIG. 7 is used.

  The third embodiment is the same as the second embodiment except that the timing of the step of pressing the powder layer 1a in the thickness direction is different.

  Specifically, first, as shown in FIG. 10A, the laser sintering powder 1 is placed in the hopper 34 of the laser sintering apparatus 25. Next, the laser sintering powder 1 is supplied from the discharge port 34 a to the bottom 30 a of the container 30. As the moving stage 33 moves, the surface of the supplied powder 1 for laser sintering is leveled, so that a first powder layer 1a having a substantially constant thickness is formed as shown in FIG. (Powder layer forming step).

  Next, as shown in FIG. 10C, hot air 23 flows toward the first powder layer 1a. Thereby, the first powder layer 1a is heated. Next, the laser beam 4 is irradiated so as to be focused on the first powder layer 1a (laser sintering step). Thus, a predetermined pattern is drawn on the first powder layer 1a. As a result, as shown in FIG. 10D, a sintered layer 1b in which the metal particles 2 are sintered is formed in the first powder layer 1a where the laser beam 4 is irradiated.

  Next, the surface of the first powder layer 1a is pressed in the thickness direction by the pressing mechanism 39 (powder layer pressing step). As a result, the first powder layer 1a is crushed in the thickness direction as shown in FIG. 10 (e), the volume contracts, and consolidation is achieved. That is, by moving the roller 392 along the surface of the first powder layer 1 a while rotating the roller 392, the first powder layer 1 a is crushed in the thickness direction by the roller 392. At this time, when the sintered layer 1b exists in the moving path of the roller 392, the distance between the bottom 30a of the container 30 and the roller 392 depends on the sintered layer 1b and cannot be further reduced. Accordingly, the thickness of the first powder layer 1a is consolidated until the thickness is the same as the thickness of the sintered layer 1b. Even when the sintered layer 1b is not present in the moving path of the roller 392, when the first powder layer 1a is consolidated, the thickness of the sintered layer 1b should be approximately the same. preferable. Accordingly, when the second powder layer 1a is formed so as to overlap the first powder layer 1a and the sintered layer 1b, the powder layer 1a having a uniform thickness can be easily formed.

  Next, as shown in FIG. 10F, the second powder layer 1a of the laser sintering powder 1 is formed so as to overlap the first powder layer 1a and the sintered layer 1b ( Powder layer forming step).

  Next, as shown in FIG. 11A, the hot air 23 flows toward the second powder layer 1a. Thereby, the second powder layer 1a is heated. Next, the laser beam 4 is irradiated so as to be focused on the second powder layer 1a (laser sintering step). Thereby, a predetermined pattern is drawn on the second powder layer 1a. As a result, as shown in FIG. 11B, a sintered layer 1b in which the metal particles 2 are sintered is formed in the second powder layer 1a where the laser beam 4 is irradiated.

  Next, the surface of the second powder layer 1a is pressed in the thickness direction by the pressing mechanism 39 (powder layer pressing step). As a result, the second powder layer 1a is crushed in the thickness direction as shown in FIG. 11C, the volume contracts, and consolidation is achieved. Also in this case, when the sintered layer 1b is present in the movement path of the roller 392, the second powder layer 1a is consolidated until the thickness of the second powder layer 1a is approximately the same as the thickness of the sintered layer 1b. The Rukoto.

  Thereafter, the step of forming the powder layer 1a so as to overlap the drawn and formed sintered layer 1b, the step of emitting the laser beam 4 toward the powder layer 1a, and the pressure of the powder layer 1a in the thickness direction The steps are repeated in this order. As a result, as shown in FIG. 11D, the container 30 is formed with a structure 49 in which a large number of sintered layers 1b sintered in a predetermined pattern are laminated. Then, as shown in FIG. 11 (e), the structure 49 is removed from the container 30 and the laser sintering powder 1 adhered to the structure 49 is removed, thereby completing the manufacture of the structure 49.

  In the structure 49 obtained by the above forming method, the powder layer 1a is pressurized after the powder layer 1a is irradiated with the laser beam 4 to form the sintered layer 1b. And it is easy to arrange the height of the surface of the sintered layer 1b. For this reason, when the new powder layer 1a is formed on the surfaces of the powder layer 1a and the sintered layer 1b, the powder layer 1a having a uniform thickness can be formed. As a result, the structure 49 having a target shape can be manufactured.

  In the third embodiment as described above, the same operations and effects as those in the first and second embodiments can be obtained.

Next, specific examples of the present invention will be described.
12 and 13 are diagrams showing an example in which metal particles of SUS301 are sintered. In FIG. 12, the metal particles 2 were used by forming particles of an alloy containing iron, nickel and chromium. The metal particles 2 are manufactured by a water atomization method. And the metal particle 2 from which an average particle diameter differs was obtained by changing manufacturing conditions. PVA was used as the binder, and ion-exchanged water was used as the solvent.

  The mixture of the metal particles 2, the binder and the solvent was put into the second container of the spray drying apparatus shown in FIG. Then, droplets composed of the metal particles 2, the binder and the solvent are dropped from the discharge port 16, and the droplets are divided by a rotating plate to form fine droplets. The fine droplets are dried by hot air, and are used for laser sintering powder. 1 (granulated powder) was obtained. And the powder 1 for laser sintering of each kind of average particle diameter was obtained by changing the magnitude | size of a droplet and the speed of a rotating plate.

  The average particle size of the metal particles 2 and the average particle size of the powder 1 for laser sintering are determined by a laser diffraction type particle size distribution measuring device (Microtrack, manufactured by Nikkiso Co., Ltd., HRA9320-X100). The particle size at 50% accumulation was obtained.

  In FIG. 13, as shown in Examples 1 to 36, granulation was performed using metal particles 2 having an average particle size of about 3 μm to 13 μm to form a laser sintering powder 1 having an average particle size of 25 μm to 55 μm. . In Example 1, granulation was performed using metal particles 2 having an average particle diameter of 5.1 μm to form powder 1 for laser sintering having an average particle diameter of 30 μm. And the structure 49 was formed by sintering the powder 1 for laser sintering.

  As shown in Examples 1 to 15, when the average particle diameter of the metal particles 2 is 5 μm to 10 μm and the average particle diameter of the laser sintering powder 1 is 30 μm to 50 μm, the surface of the formed structure may be glossy. Results were obtained.

  As shown in Examples 16 to 20, when the average particle diameter of the metal particles 2 is 5 μm to 10 μm and the average particle diameter of the laser sintering powder 1 exceeds 50 μm, the surface of the formed structure is glossy. There was no bad result. As shown in Examples 21 to 25, when the average particle diameter of the metal particles 2 is 5 μm to 10 μm and the average particle diameter of the powder 1 for laser sintering is less than 30 μm, the laser beam 4 is irradiated. The metal particles 2 moved and the structure became defective. Therefore, bad results were obtained under the conditions of Examples 21 to 25.

  As shown in Examples 26 to 34, when the average particle size of the metal particles 2 exceeds 10 μm and the average particle size of the powder 1 for laser sintering is 30 μm to 50 μm, the surface of the formed structure is There was no gloss and the result was bad. As shown in Example 35 and Example 36, when the average particle size of the metal particles 2 is less than 5 μm, the normal laser sintering powder 1 can be granulated with a large variation in the particle size of the laser sintering powder 1. could not.

  14-16 is a figure which shows the Example which sintered each kind of metal particle mainly having iron. 14 to 16, when the average particle size of the metal particles 2 is 5 μm to 10 μm and the average particle size of the laser sintering powder 1 is 30 μm to 50 μm, as shown in Examples 37 to 48, The surface of the formed structure was glossy and good results were obtained. As shown in Example 49, when the average particle diameter of the metal particles 2 exceeds 10 μm and the average particle diameter of the laser sintering powder 1 exceeds 50 μm, the surface of the formed structure is not glossy and is bad. As a result. Similarly, as shown in Example 50, even when the average particle diameter of the metal particles 2 is 5 μm to 10 μm, the surface of the formed structure is glossy when the average particle diameter of the laser sintering powder 1 exceeds 50 μm. There was no bad result.

  17 and 18 are diagrams showing examples in which various types of metal particles mainly composed of cobalt are sintered. In FIGS. 17 and 18, as shown in Examples 51 to 58, when the average particle diameter of the metal particles 2 is 5 μm to 10 μm and the average particle diameter of the laser sintering powder 1 is 30 μm to 50 μm, The surface of the formed structure was glossy and good results were obtained.

  19 and 20 are diagrams showing examples in which various types of metal particles mainly composed of nickel are sintered. 19 and 20, when the average particle diameter of the metal particles 2 is 5 μm to 10 μm and the average particle diameter of the laser sintering powder 1 is 30 μm to 50 μm, as shown in Examples 59 to 64, The surface of the formed structure was glossy and good results were obtained.

  FIG. 21 is a diagram showing an example in which SUS316L metal particles are sintered. In FIG. 21, the metal particles 2 were used by forming particles of an alloy containing iron, nickel and chromium. The metal particles 2 are manufactured by a water atomization method or a gas atomization method. And the metal particle 2 from which an average particle diameter differs by each of the water atomizing method and the gas atomizing method was obtained by changing manufacturing conditions. PVP was used as the binder, and ion-exchanged water was used as the solvent.

  In FIG. 21, as shown in Examples 65 to 70, when the average particle diameter of the powder 1 for laser sintering is 3 to 10 times the average particle diameter of the metal particles 2, the surface of the formed structure is Glossy and good results were obtained.

  In addition, when the metal particles 2 manufactured by the water atomization method are used, the dimensional accuracy of the formed structure is higher than when the metal particles manufactured by the gas atomization method are used (the deviation from the design value is Small). This dimensional accuracy was evaluated by comparing the magnitude of deviation between the actual measurement value of the height (thickness) of the structure 49 and the design value.

  In Examples 65 to 70, when the aspect ratios of the metal particles 2 were compared, the average value of the aspect ratios (minor axis S / major axis L) of the metal particles 2 produced by the water atomization method was 0.54. On the other hand, the average value of the aspect ratio of the metal particles 2 produced by the gas atomizing method was slightly high, 0.86 to 0.94, whereas it was about ˜0.75.

  FIG. 22 is a view showing an example in which SUS316L metal particles are used and sintered by adding a powder layer pressing step performed before the laser sintering step (exposure). Also in FIG. 22, the metal particles 2 are manufactured by the water atomizing method or the gas atomizing method. And the metal particle 2 from which an average particle diameter differs by each of the water atomizing method and the gas atomizing method was obtained by changing manufacturing conditions. PVP was used as the binder, and ion-exchanged water was used as the solvent.

  In FIG. 22, as shown in Examples 71 to 76, when the metal particles 2 manufactured by the water atomizing method are used, the formed structure is compared with the case of using the metal particles manufactured by the gas atomizing method. It was confirmed that the dimensional accuracy of the was high (deviation from the design value was small).

  Furthermore, by comparing FIG. 21 and FIG. 22, by providing the powder layer pressurizing step prior to the laser sintering step (exposure), it is manufactured as compared with the case where the powder layer pressurizing step is not provided. It was recognized that the dimensional accuracy of the structure 49 can be improved.

  FIG. 23 is a diagram showing an example in which SUS316L metal particles are used and sintered by adding a powder layer pressing step performed after the laser sintering step (exposure). Also in FIG. 23, the metal particles 2 are manufactured by a water atomizing method or a gas atomizing method. And the metal particle 2 from which an average particle diameter differs by each of the water atomizing method and the gas atomizing method was obtained by changing manufacturing conditions. PVP was used as the binder, and ion-exchanged water was used as the solvent.

  In FIG. 23, as shown in Examples 77 to 82, when the metal particles 2 manufactured by the water atomizing method are used, the formed structure is compared with the case of using the metal particles manufactured by the gas atomizing method. It was confirmed that the dimensional accuracy of the was high (deviation from the design value was small).

  Further, by comparing FIG. 21 with FIG. 23, even when the powder layer pressurizing step is provided after the laser sintering step (exposure), it is manufactured as compared with the case where the powder layer pressurizing step is not provided. It was recognized that the dimensional accuracy of the structure 49 could be increased.

  FIG. 24 is a view showing an example in which metal particles of SUS316L are used, a spray drying method or a tumbling granulation method is used as a granulation method, and a powder layer pressurizing step is added to perform sintering. In FIG. 24, the metal particles 2 are manufactured by the water atomization method. And the metal particle 2 from which an average particle diameter differs was obtained by changing manufacturing conditions. PVA was used as the binder, and ion-exchanged water was used as the solvent.

  In FIG. 24, as shown in Examples 83 to 88, when the laser sintering powder 1 manufactured by the spray drying method is used, the laser sintering powder 1 manufactured by the rolling granulation method is used. It was recognized that the dimensional accuracy of the formed structure was higher than that of the case.

  In addition, when the cross section of the powder 1 for laser sintering manufactured in Examples 83 to 85 was observed with an electron microscope, the presence of pores was recognized in the particles having a number ratio of 50% or more. Of these, when the volume ratio of the pores was calculated for 100, it was about 5 to 50% by volume.

  On the other hand, when the cross section of the laser sintering powder 1 produced in Examples 86 to 88 was observed with an electron microscope, there were almost no particles in which pores were observed (number ratio of 20% or less). .

As described above, this embodiment has the following effects.
(1) According to this embodiment, the laser sintering powder 1 has a plurality of metal particles 2 bonded together by a binder 3. The laser sintering powder 1 is disposed in a predetermined thickness. And when the laser beam 4 is irradiated to the laser sintering powder 1, the metal particles 2 irradiated to the laser beam 4 are heated, and the binder 3 is decomposed and gasified. At this time, a large energy is applied to a shallow place of the laser sintering powder 1 and a small energy is applied to a deep place. Since the heat capacity of the metal particles 2 can be reduced when the metal particles 2 are small, the temperature of the metal particles 2 can be easily increased. Therefore, since the temperature of the metal particles 2 located in the deep place can be increased, the sintered metal can be surely sintered even in the deep place.

  (2) According to the present embodiment, the laser sintering powder 1 is repeatedly subjected to the step of arranging the powder layer 1a in a predetermined thickness and the step of drawing a predetermined pattern by the laser beam 4. When the heating of the metal particles 2 by the laser beam 4 has a difference in the depth direction, a layer in which sintering is completely performed and a layer incompletely sintered is laminated. In the laser sintering powder 1 of this embodiment, since the metal particles 2 have a small particle size, the heating of the metal particles 2 by the laser light 4 is suppressed from causing a difference in the depth direction. As a result, the laser-sintered structure 49 can have a glossy surface on the left and right side surfaces in the figure. Furthermore, the structure 49 formed by irradiating the laser sintering powder 1 with the laser beam 4 has less anisotropy in the depth direction in strength. Furthermore, the laser-sintered structure 49 can be made into a structure 49 that is unlikely to peel off between layers.

  (3) According to this embodiment, the average particle diameter of the laser sintering powder 1 is not less than 30 μm and not more than 50 μm. When arranged with a predetermined thickness and drawn with the laser beam 4, the powder 1 for laser sintering having an average particle size of 30 μm or more and 50 μm or less is a powder that does not rise easily. Accordingly, since the metal can be sintered to a thickness with high accuracy, the structure 49 can be formed with high accuracy.

  (4) According to this embodiment, since the average particle diameter of the metal particles 2 is 5 μm or more and 10 μm or less, the heat capacity of the metal particles 2 can be reduced and the temperature during heating can be easily increased. As a result, since the metal particles 2 can be sintered with high quality, the structure 49 can be formed with high quality.

  (5) According to this embodiment, the metal particles 2 are heated to a temperature at which they are sintered without melting. If the metal is heated until it melts, the molten metal flows in the direction in which gravity acts. It is not heated until the metal is melted, but is heated at a temperature at which it is sintered, so that the metal can be formed in a shape drawn with high accuracy. Therefore, the shape of the structure 49 can be formed with high accuracy.

  (6) According to the present embodiment, the metal particles 2 are arranged in the thickness direction. Therefore, the side surface of the structure 49 can be a surface having a small surface roughness.

  Note that the present embodiment is not limited to the above-described embodiment, and various changes and improvements can be added by those having ordinary knowledge in the art within the technical idea of the present invention. A modification will be described below.

(Modification 1)
In the said embodiment, the laser beam 4 is irradiated to the powder layer 1a, and the powder layer 1a is sintered. Further, the sintered layer 1b may be heated. Thereby, it can be set as the structure 49 with strong peeling strength.

(Modification 2)
In the embodiment, the structure 49 is formed by stacking the sintered layers 1b. Further, the structure 49 may be subjected to heat treatment. The performance of the structure 49 can be improved. In addition, surface treatment may be performed as post-processing.

(Modification 3)
In the embodiment, the scanner 41 scans the laser beam 4. The XY stage 28 may scan the container 30. Then, the mirror 41a may be fixed excluding the scanner 41. Thereby, the laser sintering apparatus 25 can be easily manufactured.

(Modification 4)
In the embodiment, the hot air blowing unit 43 is installed in the laser sintering apparatus 25. When the metal particles 2 can be sintered by the laser beam 4 without applying the hot air 23 to the laser sintering powder 1, the hot air blowing section 43 may be a blowing section that does not have heating means. Alternatively, the hot air blowing section 43 and the blowing pipe 44 may not be installed. Thereby, the component of the laser sintering apparatus 25 can be reduced and it can be made easy to manufacture.

(Modification 5)
In the above embodiment, the powder layer pressing step is performed before or after the laser sintering step. However, the powder layer pressing step may be performed both before and after the laser sintering step. Thereby, the dimensional accuracy of the structure 49 to be manufactured can be further increased.

DESCRIPTION OF SYMBOLS 1 Laser sintering powder 1a Powder layer 1b Sintered layer 2 Metal particle 3 Binder 4 Laser light 5 Spray drying apparatus 6 First container 6a Ceiling 7 Disc rotating part 8 Raw material dropping part 9 Hot air blowing part 10 Motor 10a Rotating shaft 11 Rotating plate 12 Second container 13 Solvent 14 Motor 14a Rotating shaft 15 Impeller 16 Discharge port 16a Solenoid valve 17 Droplet 18 Motor 18a Rotating shaft 21 Impeller 22 Heater 23 Hot air 24 Micro droplet 25 Laser sintering device 26 XYZ stage 27 Table 28 XY stage 29 Lifting device 30 Container 30a Bottom 31 Powder supply device 32 Rail 33 Moving stage 34 Hopper 34a Discharge port 35 Electromagnetic valve 36 Plate 37 Laser irradiation unit 38 Laser light source 39 Pressure mechanism 391 Rotating shaft 392 Roller 393 Lifting device 41 Scanner 41a Mirror 42 Condensing lens 43 Hot air blowing section 44 Blower pipe 44a Spout 45 Control section 46 Chamber 47 Inert gas 48 Inert gas supply section 49 Structure

Claims (10)

A laser sintering powder that is sintered by irradiating laser light,
A plurality of metal particles having an average aspect ratio defined by the minor axis / major axis of 0.3 to 0.9 ;
A binder that binds the plurality of metal particles to each other , and includes a material that decomposes and gasifies by the laser beam ;
Have
The average particle size is 3 to 10 times the average particle size of the metal particles, and 30 to 50 μm,
A laser sintering powder comprising pores in a proportion of 1 to 50% by volume of the laser sintering powder. Laser sintering powder according to claim 1, wherein the average particle diameter of the metal particles is 5μm or more 10μm or less. The powder for laser sintering according to claim 1 or 2 , wherein the metal particles contain any one of iron, nickel, and cobalt as a main component. The powder for laser sintering according to claim 3 , wherein the metal particles include iron as a main component and at least one of nickel, chromium, molybdenum, and carbon. The powder for laser sintering according to any one of claims 1 to 4 , wherein the material decomposed and gasified by the laser light is polyvinyl alcohol or polyvinylpyrrolidone . A powder layer comprising a laser sintering powder in which a plurality of metal particles are bonded by a binder , and the average particle size is 3 to 10 times the average particle size of the metal particles. A powder layer forming step to be formed;
A laser sintering step of injecting a laser beam to the powder layer to draw a predetermined pattern and gasifying the binder to sinter the metal particles;
Have
A structure in which the metal particles are sintered is formed by repeating the powder layer forming step of forming the powder layer on the drawn powder layer and the laser sintering step. Manufacturing method of structure. The method of manufacturing a structure according to claim 6 , wherein the metal particles irradiated with the laser light are heated to a temperature at which the metal particles are not melted and sintered. Furthermore, the manufacturing method of the structure of Claim 6 or 7 which has a powder layer pressurization process which pressurizes the said powder layer in the thickness direction. Furthermore, the manufacturing method of the structure of any one of Claim 6 thru | or 8 which has the metal particle manufacturing process which manufactures the said metal particle by the atomizing method. The method for producing a structure according to claim 9, further comprising a granulated particle production step that is provided after the metal particle production step and granulates the metal particles by a spray drying method to produce the laser sintering powder. .

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