JP2004277877A - Metal powder for metal light mold molding, method of producing the same, method of producing molding with three-dimensional shape by metal light molding and metal light molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a molding which has excellent moldability on metal light molding, and has no microcracks. <P>SOLUTION: In the metal powder for metal light molding, a powder layer consisting of metal powder is irradiated with an optical beam to form a sintered layer, and further, the sintered layers are stacked to obtain a molding with a desired three-dimensional shape. The metal powder consists of iron based powder, the powder of nickel or a nickel based alloy and the powder of copper or a copper based alloy, and further, graphite powder is mixed therein. The graphite powder improves its wettability on melting, and reduces the generation of microcracks on solidification. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a metal powder used for metal stereolithography to irradiate a light beam to a powder layer made of a metal powder to form a sintered layer and to laminate the sintered layer to obtain a desired three-dimensional molded object. The present invention relates to a manufacturing method, a method of manufacturing a three-dimensionally shaped object by metal stereolithography, and a metal stereolithography.

  A powder layer formed of a metal powder is irradiated with a light beam (directional energy beam, for example, a laser) to form a sintered layer, and a new powder layer is formed on the sintered layer and irradiated with a light beam. A technique for manufacturing a three-dimensionally shaped object by repeating the formation of a sintered layer in this way is known. In this technology, which is called metal stereolithography, by adjusting the energy density of the light beam, the metal powder is almost completely melted and solidified after a large number of gaps (voids) exist in the modeled object It is possible to obtain a molding state (ie, a molding density (sintering density) of up to almost 100%), and therefore, it is necessary to form a molding die or the like that requires a smooth surface. You can also. In addition, it is possible to form a high density surface, a low density inside, and a medium density in the meantime, and when changing the density in this way, without sacrificing the modeling speed, a thing with a smooth surface Obtainable.

  However, in order to obtain a shaped article having such a density difference between the surface and the inside by metal stereolithography, it is necessary to have a property different from that of a metal powder used for ordinary powder sintering.

  For example, the particle size of the metal powder needs to be smaller than the thickness of the powder layer. At this time, the smaller the particle size, the higher the packing density of the powder and the better the light beam (laser) absorptivity at the time of molding. Although the molding density can be increased and the surface roughness can be reduced, if the powder is too fine and causes agglomeration, on the contrary, the packing density of the powder becomes small, and the powder cannot be spread thinly and uniformly.

  In addition, in order to obtain a certain level of molding strength, the bonding area between the laser-irradiated modeled part and the underlying sintered layer must be large, and its adhesion strength must be high, and at the same time, the adjacent sintered layer Must have a large bonding area and a high adhesion strength.

  Further, the upper surface of the portion irradiated with the laser should not be raised too much. When the next powder layer is laid to form the next layer, if the amount of swelling is greater than the thickness of the powder layer, the formation of the powder layer itself may be difficult.

  In addition, since metal powder has adhered to the surface of the modeled object, processing such as cutting to remove this unnecessary metal powder and expose a high-density surface is performed. It is desirable that the property is good.

  Of course, no large cracks should be generated in the appearance, and in consideration of the case where a fluid (cooling water) is flown into the interior of an injection molding die or the like, it is desired that the internal structure has no microcracks.

  Here, a part or the whole of the laser powder irradiated with the laser is once melted and then rapidly solidified to form a sintered product. Since the swelling becomes small when the joining area becomes large and the fluidity is large, it is desired that the fluidity when molten is large and the wettability is good.

  From such a viewpoint, the present applicant disclosed in Japanese Patent Application No. 11-335178 (JP-A-2001-152204: Patent Document 1) a mixture of chromium molybdenum steel, phosphorous copper or manganese copper, and each powder of nickel. A metal powder for metal stereolithography was proposed. Chromium molybdenum steel is employed from the viewpoint of strength and toughness, phosphorous copper or manganese copper is employed from the viewpoint of wettability and fluidity, and nickel is employed from the viewpoint of strength and workability.

The metal powder for metal stereolithography having the above composition can generally obtain favorable results in that a molded article having a density difference between the surface and the interior is obtained by metal stereolithography by metal stereolithography. There are some problems during molding in terms of fluidity and fluidity, and workability (cuttability) is not very good, and most importantly, as shown in FIG. Many micro cracks are generated in the sintered part. This microcrack becomes a problem when the obtained shaped article is used as a molding die.
JP 2001-152204 A

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a metal powder which is excellent in moldability at the time of metal stereolithography and which can obtain a molded article without micro cracks. Another object of the present invention is to provide a method for producing a metal powder material that can easily obtain the above-mentioned metal powder in which a plurality of types of powders are blended, and yet another object is injection molding. In order to provide a method for manufacturing a three-dimensionally shaped object by metal stereolithography, which can easily obtain a shaped object that can be suitably used for a molding die, etc., and can be used as an injection molding die To provide a novel metal stereolithography.

  Thus, the metal powder for metal stereolithography according to the present invention is formed by irradiating a powder layer made of metal powder with a light beam to form a sintered layer and laminating this sintered layer to form a desired three-dimensionally shaped object. Metal powder for stereolithography, obtained from iron-based powder, nickel or nickel-based alloy powder, copper or copper-based alloy powder, and graphite powder is mixed Has features. The graphite powder here is used for the purpose of lowering the melting point of the sintered material and improving the sintering density in iron-based powder sintering, etc., but the graphite powder here has a wettability during melting. It improves and reduces the occurrence of microcracks during solidification.

  It is desirable that the compounding amount of the graphite powder be within 1% by weight. If it exceeds 1% by weight, the effect of reducing microcracks cannot be obtained.

  In particular, the compounding amount of the iron-based powder is 60 to 90% by weight, the compounding amount of the nickel or nickel-based alloy powder is 5 to 35% by weight, and the compounding amount of the copper or copper-based alloy powder is 5 to 15% by weight. At one time, the compounding amount of the graphite powder is preferably 0.2 to 1.0% by weight. The effect of adding the graphite powder appears well.

  In addition, satisfying at least one of the conditions of whether the iron-based powder is chromium molybdenum steel powder or the copper-based alloy powder is a copper-manganese alloy powder is advantageous in terms of moldability and the improvement of characteristics due to the addition of graphite powder. Gives favorable results.

  The amount of the chromium molybdenum steel powder is 60 to 80% by weight, the amount of the nickel powder is 15 to 25% by weight, the amount of the copper manganese alloy powder is 5 to 15% by weight, and the amount of the graphite powder is 0. When the content is 2 to 0.75% by weight, particularly favorable results can be obtained in various points such as reduction of microcracks and improvement of moldability.

  It is desirable that the average particle size of each of the iron-based powder and nickel or the powder of the nickel-based alloy and the powder of copper or the copper-based alloy is 5 to 50 μm, but the average particle size of the iron-based powder is nickel or And the average particle diameter of each powder of nickel-based alloy powder and copper or copper-based alloy powder, especially the average particle diameter of iron-based powder, nickel or nickel-based alloy powder and copper or copper It is desirable that the average particle size of the powder of the base alloy be approximately 3/4 or less with respect to the reduction of microcracks.

  In addition, as metal powder for metal stereolithography, it is generally said that the powder particles are preferably spherical particles and have a narrow particle size distribution in order to laminate the powders at high density and uniformity, but graphite powder is added. In this case, the iron-based powder is preferably non-spherical particles, and the nickel or nickel-based alloy powder and the copper or copper-based alloy powder are preferably spherical particles. In particular, when the iron-based powder is chromium molybdenum steel powder, it is preferable that the iron-based powder is non-spherical particles having an average particle diameter of 25 μm or less. This is effective in that the dispersion of the graphite powder is improved, and that the iron-based powder is well melted.

  As the graphite powder, those having a maximum particle length of not more than the average particle diameter of the iron-based powder can be suitably used. If the graphite powder is fine, carbon will penetrate into iron and lower the melting point when it is melted by laser irradiation, so that the flowability at the time of melting is improved and the unevenness of the surface of the sintered layer is reduced.

  It is also preferable to mix a carbide-forming element. Since the precipitation of surplus carbon can be prevented, high-density, high-strength, high-hardness modeling can be performed, and the surface roughness after cutting can be improved by eliminating the precipitated carbon.

  Further, the metal powder here may be formed as granulated powder.

  And the manufacturing method of the metal powder for metal stereolithography according to the present invention is to mix the flake graphite and to grind the flake graphite at the time of mixing, so that the handling of the graphite is easy at the time of blending and mixing each powder. At the same time, the graphite powder can be homogeneously dispersed.

  Further, the method for producing a three-dimensionally shaped object by metal stereolithography according to the present invention includes irradiating a light beam on a desired portion of the powder layer formed of the metal powder described above to form a sintered layer on a desired portion. And then forming a new powder layer of the metal powder on the sintered layer and irradiating a desired portion of the powder layer with a light beam to be integrated with the previously formed sintered layer. It is characterized by forming a desired three-dimensionally shaped object by repeating forming a new sintered layer, the metal stereolithography according to the present invention is manufactured by the manufacturing method described above Is characterized by the fact that

  According to the above manufacturing method, it is possible to easily produce a metal stereolithography having good characteristics even if there is a density difference between the surface and the inside, and the metal stereolithography produced by this production method has an appearance crack. Needless to say, there is almost no microcrack in the internal structure, and it can be used as a mold for injection molding.

  In the metal powder for metal stereolithography of the present invention, the addition of graphite powder is effective for improving wettability during melting and reducing the occurrence of microcracks during solidification, and for the metal powder for metal stereolithography of the present invention. In the production method of (1), the graphite can be easily handled and can be dispersed homogeneously, and the effect of adding graphite can be advantageously derived.

  Further, in the method of manufacturing a three-dimensionally shaped object by metal stereolithography according to the present invention, a metal stereolithographic object having good characteristics can be easily manufactured even if there is a difference in density between the surface and the inside.

  Hereinafter, the present invention will be described in detail based on an example of an embodiment. In the illustrated example, there is shown a device provided with a removing means 4 for cutting in the middle of modeling to perform cutting of the surface of the modeled object in the middle of modeling. The present invention can be applied to ordinary metal stereolithography which does not have the means 4 and does not perform cutting during molding.

  FIG. 2 shows an example of an apparatus for metal stereolithography, in which a metal powder supplied onto an elevating table 20 which moves up and down by a cylinder in a space surrounded by an outer periphery is leveled by a squeezing blade 21. By irradiating the powder layer 10 with the powder layer forming means 2 for forming the powder layer 10 having a predetermined thickness Δt1 via a scanning optical system such as a galvanometer mirror 31 or the like, the metal powder is baked. A sintering layer forming means 3 for sintering to form a sintered layer 11; and a removing means 4 formed by providing a milling head 41 on a base portion of the powder layer forming means 2 via an XY drive mechanism 40. ing.

  As shown in FIG. 3, the production of the three-dimensionally shaped object is performed by adjusting the relative distance between the sintered layer forming means and the sintered layer, as shown in FIG. The first powder layer 10 is formed by supplying the metal powder to the surface with the blade 21 and leveling it with the blade 21 at the same time. Is sintered to form a sintered layer 11 integrated with the base 22.

  Thereafter, the elevating table 20 is slightly lowered, metal powder is supplied again and leveled by the blade 21 to form a second powder layer 10, and a light beam (laser) is applied to a position where the powder layer 10 is to be hardened. The powder is sintered by irradiating L to form a sintered layer 11 integrated with the lower sintered layer 11.

  By lowering the elevating table 20 to form a new powder layer 10 and irradiating a light beam to form a sintered layer 11 at a required portion, a process for manufacturing a target three-dimensional shaped object is performed. Yes, a carbon dioxide laser can be suitably used as the light beam, and the thickness Δt1 of the powder layer 10 is about 0.05 mm when the obtained three-dimensionally shaped object is used for a molding die or the like. Is preferred.

  The irradiation path of the light beam is created in advance from the three-dimensional CAD data. That is, the contour shape data of each section obtained by slicing the STL data generated from the three-dimensional CAD model at a constant pitch (0.05 mm pitch when Δt1 is 0.05 mm) is used. At this time, a light beam is irradiated so that at least the outermost surface of the three-dimensionally shaped object can be sintered so as to have a high density (porosity of 5% or less), and the inside is sintered so as to have a low density. In other words, the shape model data is divided into the surface layer and the interior in advance, and the sintering conditions are such that the inside is porous, and the surface layer is the condition where the powder is almost melted and the density is high. By irradiating with a light beam, a model having a dense surface can be obtained at high speed.

  Then, the formation of the powder layer 10 and the irradiation of the light beam to form the sintered layer 11 are repeated. The total thickness of the sintered layer 11 is, for example, the tool length of the milling head 41 or the like. When the required value obtained from is obtained, the removing means 4 is once operated to cut the surface of the modeled object formed up to that time. For example, if the tool (ball end mill) of the milling head 41 is capable of cutting with a diameter of 1 mm, an effective blade length of 3 mm, and a depth of 3 mm, and the thickness Δt1 of the powder layer 10 is 0.05 mm, the baking of 60 layers is performed. When the tie layer 11 is formed, the removing means 4 is operated.

  The low density surface layer of the powder attached to the surface of the modeled object is removed by the cutting process by the removing unit 4 and the high density portion is entirely exposed on the surface of the modeled object by cutting down to the high density portion.

  The cutting path by the removing means 4 is created in advance from the three-dimensional CAD data, similarly to the irradiation path of the light beam. At this time, the processing path is determined by applying the contour processing, but the Z-direction pitch does not need to stick to the lamination pitch at the time of sintering, and in the case of a gentle inclination, the Z-direction pitch is made finer and interpolated. Be prepared to obtain a smooth surface.

  In manufacturing such a three-dimensionally shaped object by metal stereolithography, as described above, what kind of metal powder is used has a significant effect on the moldability and the finished state of the shaped object. However, from the above-mentioned point required as a metal powder for metal stereolithography, using a powder composed of iron-based powder, nickel or a nickel-based alloy powder, and copper or a copper-based alloy powder In the present invention, a mixture of graphite powder is used.

  Even in the case of iron-based powder sintering, graphite is added for the purpose of lowering the melting point of the sintered material or improving the sintering density, but the light beam is applied to the extremely thin powder layer 10 having a thickness Δt1 of 0.05 mm. In the case of irradiating and melting, there has been no attempt so far as the addition of graphite is unnecessary, but the present inventors have improved the wettability at the time of melting and at the time of solidification of the high-density portion. It has been found that the addition of graphite powder is very effective in reducing the occurrence of microcracks. The reason why the addition of the graphite powder reduces the occurrence of microcracks is not clear, but a state in which a lump of graphite is scattered in the cross-section after modeling (black dots in FIG. 1) is observed.

  The compounding amount of the graphite powder depends on the compounding of the other metal powder materials, but it is preferable that the compounding amount is approximately 1% by weight or less, particularly, the compounding amount of the iron-based powder is 60 to 90% by weight, nickel or nickel-based alloy. When the amount of the powder is 5 to 35% by weight and the amount of the copper or copper alloy powder is 5 to 15% by weight, the amount of the graphite powder is 0.2 to 1.0% by weight. It is desirable. When the blending amount of the graphite powder exceeds 1% by weight, the effect of reducing microcracks is completely lost, and microcracks equivalent to the case where no graphite powder is added are generated.

  As the metal material, chromium molybdenum steel powder can be suitably used as the iron-based powder, and copper manganese alloy powder can be suitably used as the copper-based alloy powder. When at least one of these two conditions is satisfied, the improvement of the characteristics by the addition of the graphite powder can be obtained more reliably.

  The amount of chromium molybdenum steel powder is 60 to 80% by weight, the amount of nickel powder is 15 to 25% by weight, the amount of copper manganese alloy powder is 5 to 15% by weight, and the amount of graphite powder is 0. When the content was 2 to 0.75% by weight, microcracks did not occur in the high-density portion, and good moldability was obtained in both the high-density portion and the low-density portion.

  The average particle diameter of each of iron-based powder and nickel or nickel-based alloy powder and copper or copper-based alloy powder is preferably 5 to 50 μm. When the thickness Δt1 of the powder layer 10 is set to 0.05 mm, the average particle diameter is preferably set to approximately 30 μm.

  However, as metal powder for metal stereolithography, it is generally considered preferable that the powder particles be spherical particles and have a narrow particle size distribution in order to stack the powders with high density and uniformity. However, when graphite powder is added, the iron-based powder is non-spherical particles, and the nickel- or nickel-based alloy powder and the copper or copper-based alloy powder are each spherical particles, especially the iron-based powder. Chromium molybdenum steel powder having a non-spherical particle shape with an average particle size of 25 μm or less, approximately 3/4 or less of the average particle size of each of nickel or nickel-based alloy powder and copper or copper-based alloy powder , Good results could be obtained.

[Example]
A chromium molybdenum steel SCM440 powder having a non-spherical particle shape and an average particle size of 20 μm (see FIG. 4), a nickel Ni powder having a spherical particle shape and an average particle size of 30 μm (see FIG. 5), and a spherical particle shape having an average particle size A copper manganese alloy CuMnNi (for example, Cu-10% Mn-3% Ni) powder of 30 μm (see FIG. 6) was prepared, and the following six types of metal powders for metal stereolithography with different amounts of graphite C were prepared. Formed. In addition, each% is weight%.
a. 70% SCM440-21% Ni-9% CuMnNi
b. (70% SCM440-21% Ni-9% CuMnNi) + 0.2% C
c. (70% SCM440-21% Ni-9% CuMnNi) + 0.4% C
d. (70% SCM440-21% Ni-9% CuMnNi) + 0.5% C
e. (70% SCM440-21% Ni-9% CuMnNi) + 0.75% C
f. (70% SCM440-21% Ni-9% CuMnNi) + 1.0% C
Metal stereolithography was performed using the six types of metal powders a to f. The thickness of the powder layer was 0.05 mm, the laser used was a carbon dioxide laser (90% output of 200 W output), and the laser was scanned at a scan speed of 75 mm / sec and a scan pitch of 0.25 mm. Many microcracks were observed in the case where no graphite was added, whereas no microcracks were observed in the case where 0.5% of graphite d was added (see FIG. 1). In addition, in the case where 0.4% of graphite was added, only slight microcracks were observed. In the case where 0.2% of graphite was added and the case where 0.75% was added, the effect of reducing microcracks could be confirmed as compared with the case where graphite was not added, and 1% of graphite was added. Microcracks were found to be almost the same or slightly less than those without the addition of graphite.

  The high-density portion has a laser scan speed of 75 mm / sec and a scan pitch of 0.25 mm, the medium-density portion has a laser scan speed of 150 mm / sec and a scan pitch of 0.5 mm, and the low-density portion has a laser scan speed of 200 mm / sec. By irradiating the laser with a 0.3 mm pitch and every other layer to the powder layer, a three-dimensional shaped object having a density difference was formed. Could be confirmed from the small number of

  In addition, in the metal powder having the same composition as the above d, a chromium molybdenum steel powder having a spherical particle shape and an average particle diameter of 30 μm, which is the same as other non-ferrous metal powders, is used. When sintering was performed under the conditions of a laser scan speed of 75 mm / sec and a scan pitch of 0.25 mm, microcracks were slightly observed and voids were formed as compared with those of the above d. Although the molding density was slightly lowered, a generally good molded product could be obtained.

  In addition, when sintering was performed under the same conditions using copper phosphorus CuP alloy powder (spherical particles and an average particle diameter of 30 μm) instead of the copper manganese alloy in the above formulation d, generation of microcracks was observed, Irregularities were generated on the upper surface of the sintered layer, which hindered the formation of the next powder layer. There was also a slight problem in the bending strength.

  In addition to the copper-manganese alloy in the above formula d, copper-phosphorus alloy powder (spherical particles having an average particle diameter of 30 μm) is used, and chromium molybdenum steel powder is formed of spherical particles having an average particle diameter of other non-ferrous metal powder. When the same 30 μm was used, a better result was obtained than a combination of chromium molybdenum steel having a non-spherical particle shape and an average particle size of 20 μm and a copper phosphorus CuP alloy powder having a spherical particle shape and an average particle size of 30 μm. Although it could be obtained, generation of microcracks was observed.

  Factors that cause microcracks are different between those containing copper-phosphorus alloy powder and those containing copper-manganese alloy powder, and those containing copper-manganese alloy powder cause micro-cracking due to insufficient melting during laser sintering. It is considered that cracks were generated, and it is considered that the use of a chromium molybdenum steel powder having a smaller average particle diameter than other non-ferrous metal powders promoted melting and reduced the occurrence of microcracks.

  Also, when non-spherical particles are used as the chromium molybdenum steel powder, the graphite powder is more effectively dispersed on the surface of each particle of the chromium molybdenum steel powder than when spherical particles are used, and the graphite powder is The addition seems to be working more effectively.

  By the way, the addition of the graphite powder is performed by adding flake graphite (see FIG. 7) to iron-based powder, nickel or a nickel-based alloy powder, and copper or a copper-based alloy powder. When the mixture was ground using a mortar, no graphite powder was observed in the mixed powder (see FIG. 8). This is thought to be due to the effective dispersion of graphite on the surface of metal powder, especially non-spherical particulate chromium molybdenum steel powder, and it is possible to obtain better moldability than simply mixing graphite powder with metal powder. In addition to being able to do so, micro cracks were reduced.

  When graphite powder having a maximum particle length of less than the average particle diameter of the iron-based powder, particularly 10 μm or less, is used. Since the lower carburizing effect can be obtained and the flowability at the time of melting is improved, the irregularities on the surface of the sintered layer can be reduced.

  By the way, ultrafine particles of graphite powder having a maximum length of 1 to several μm can be obtained as carbon black which is a black fine powder obtained by incomplete combustion or thermal decomposition of natural gas or liquid hydrocarbon, and jet mill pulverization. It can also be obtained by the method.

  In addition, as described above, the black dots in FIG. 1 indicate the precipitate of graphite, but it is also preferable to previously mix carbide-forming elements in iron. If a carbide-forming element such as chromium Cr, molybdenum Mo, tungsten W, or vanadium V is mixed, carbon that tends to precipitate when solidifying from a molten state becomes a carbide by bonding with the carbide-forming element. Precipitation of carbon can be prevented.

  FIG. 9 is an SEM photograph when the tungsten W powder is added to Example d ((70% SCM440-21% Ni-9% CuMnNi) + 0.5% C + 0.5% W), and FIG. It is a SEM photograph when the system powder SCM440 is changed to SKH steel powder containing a large amount of carbide-forming elements ((70% SKH51-21% Ni-9% CuMnNi) + 0.5% C). In addition, each% is weight%. The carbon deposition is clearly reduced compared to that according to example d shown in FIG. When the precipitation of carbon is reduced in this manner, high-density, high-strength, high-hardness modeling can be performed, and the absence of precipitated carbon can also improve surface roughness after cutting. .

  The metal powder in each of the above examples may be formed as granulated powder. It becomes easy to handle. Further, a three-dimensionally shaped object obtained by performing metal stereolithography using such a metal powder has characteristics sufficient for use as a mold for injection molding.

It is a sectional photograph at a magnification of 25 times of a metal stereolithography manufactured with metal powder of an example of an embodiment of the invention. It is a schematic perspective view of an example of the apparatus which performs metal stereolithography using the same metal powder. FIG. It is a SEM photograph of the same non-spherical particle-like chromium molybdenum steel powder. It is a SEM photograph of the same spherical particle-like nickel powder. It is a SEM photograph of the same spherical particulate copper manganese alloy powder. It is a SEM photograph of the same flake graphite. It is a SEM photograph of the same mixture. It is a cross-sectional photograph at a magnification of 25 times of a metal stereolithography manufactured using a metal powder to which a carbide-forming element is added. It is a cross-sectional photograph at a magnification of 25 times of a metal stereolithography manufactured using a metal powder using an iron-based powder containing a large amount of a carbide-forming element. It is a cross-sectional photograph at a magnification of 25 times of a metal stereolithography manufactured using a metal powder of a conventional example.

Claims (16)

  A metal powder for metal stereolithography to obtain a desired three-dimensionally shaped object by forming a sintered layer by irradiating a light beam to a powder layer made of a metal powder and laminating this sintered layer, A metal powder for metal stereolithography, comprising: a base powder; a powder of nickel or a nickel-based alloy; a powder of copper or a copper-based alloy; and a mixture of graphite powder.   The metal powder for metal stereolithography according to claim 1, wherein the amount of the graphite powder is within 1% by weight.   The amount of iron-based powder is 60 to 90% by weight, the amount of nickel or nickel-based alloy powder is 5 to 35% by weight, the amount of copper or copper-based alloy powder is 5 to 15% by weight, graphite The metal powder for metal stereolithography according to claim 1 or 2, wherein the amount of the powder is from 0.2 to 1.0% by weight.   The iron-based powder is a chromium molybdenum steel powder or the copper-based alloy powder is a copper-manganese alloy powder, and satisfies at least one of the conditions of claim 1. Metal powder for metal stereolithography.   The amount of chromium molybdenum steel powder is 60 to 80% by weight, the amount of nickel powder is 15 to 25% by weight, the amount of copper manganese alloy powder is 5 to 15% by weight, and the amount of graphite powder is 0.2 to 0.2%. The metal powder for metal stereolithography according to claim 4, wherein the amount is 0.75% by weight.   The average particle diameter of each powder of iron-based powder and nickel or nickel-based alloy powder and copper or copper-based alloy powder is 5 to 50 µm, according to any one of claims 1 to 5, The metal powder for metal stereolithography according to the above.   7. The metal stereolithography according to claim 6, wherein the average particle diameter of the iron-based powder is smaller than the average particle diameter of each powder of nickel or nickel-based alloy powder and copper or copper-based alloy powder. Metal powder.   8. The metallized light according to claim 7, wherein the average particle diameter of the iron-based powder is about 3/4 or less of the average particle diameter of nickel or nickel-based alloy powder and copper or copper-based alloy powder. Molding metal powder.   The iron-based powder is non-spherical particles, and the powder of nickel or nickel-based alloy and the powder of copper or copper-based alloy are spherical particles. Metal powder for stereolithography.   The metal powder for metal stereolithography according to claim 9, wherein the iron-based powder is a chromium molybdenum steel powder and has a non-spherical particle shape having an average particle diameter of 25 µm or less.   The metal powder for metal stereolithography according to any one of claims 1 to 10, wherein a maximum length of particles of the graphite powder is equal to or less than an average particle diameter of the iron-based powder.   The metal powder for metal stereolithography according to any one of claims 1 to 11, wherein the metal powder is formed as a granulated powder.   The metal powder for metal stereolithography according to any one of claims 1 to 12, wherein a carbide-forming element is mixed.   It is a manufacturing method of the metal powder for metal stereolithography of any one of Claims 1-13, Comprising: Iron-based powder, nickel or nickel-based alloy powder, and copper or copper-based alloy powder. A method of producing a metal powder for metal stereolithography, wherein flake graphite is mixed and the flake graphite is ground during the mixing.   A light beam is applied to a desired portion of the powder layer formed of the metal powder according to any one of claims 1 to 13 to form a sintered layer at a desired portion, and then on the sintered layer. Forming a new powder layer with the metal powder and irradiating a desired portion of the powder layer with a light beam to form a new sintered layer integrated with the previously formed sintered layer. A method of manufacturing a three-dimensionally shaped object by metal stereolithography, wherein a desired three-dimensionally shaped object is formed by repeating the process.   A metal stereolithography manufactured by the method for manufacturing a three-dimensional shaped object by metal stereolithography according to claim 15.