JP3446694B2 - Powder material for manufacturing a three-dimensional shaped object, a method for producing a three-dimensional shaped object, and a three-dimensional shaped object - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for manufacturing a three-dimensional shaped object, and more specifically, a technique for manufacturing a three-dimensional shaped object by continuously curing a powder material in layers using a light beam. In the above, the object is a powder material mainly composed of a metal used for modeling, a method of manufacturing a molded article using such a powder material, and a molded article manufactured by such a method.

[0002]

2. Description of the Related Art There is known a technique of irradiating a metal powder material with a light beam (directional energy beam, for example, a laser) to form a hardened layer, and stacking the hardened layer to manufacture a three-dimensional shaped object. ing. Usually, the molded product obtained by such a method has a molded density (sintered density) of about 70%, and there are many gaps (holes) on the surface of the molded product.

For applications such as molding dies, where surface characteristics are important and, for example, surface roughness Ry = 1 μm is required,
The shaped article obtained by the above method cannot be used as it is. It is necessary to fill the gaps existing on the surface of the modeled object or finish the surface after filling the gaps.
Japanese Unexamined Patent Application Publication No. 10-88201 (Prior Art 1) forms an intermediate compact by compacting a powder deposit layer or irradiating the powder deposit layer with laser light and then compressing the whole. , A technique of further sintering this intermediate compact to obtain a dense shaped article is disclosed.

In Japanese Patent Laid-Open No. 8-39275 (Prior Art 2), a mixed powder of a metal that cannot be melted by a single high-density energy beam is simultaneously irradiated with a plurality of high-density energy beams to be melted. The technique for obtaining a modeled object is shown. Japanese Patent Publication No. 10-506151 (Prior Art 2)
In the case of producing a shaped article by sintering a mixed powder containing a copper alloy as a main component and also containing an iron group metal, the sintering is performed in a gas atmosphere containing an iron group metal compound. Thus, a technique is disclosed in which the pores of the sintered material composed of the mixed powder are filled with the reinforcing phase derived from the iron group metal compound to reduce the porosity and increase the density.

[0005]

With any of the above-mentioned prior arts, it is difficult to obtain a shaped article having a surface roughness as small as that which can be used for a molding die or the like. In Prior Art 1, even if the deposited layer is compressed or the whole is compressed, the gaps and pores are only reduced to some extent and cannot be completely eliminated.

In Prior Art 2, a device for simultaneously irradiating a plurality of high-density energy rays is required to completely melt the mixed powder of metal, and a plurality of high-density energy rays are focused and simultaneously irradiated. However, scanning requires sophisticated technology, which makes the manufacturing apparatus complicated and expensive, and lowers productivity. When the metal is completely melted and then solidified, warping or cracks are likely to occur due to thermal deformation, and the dimensional accuracy of the modeled object is deteriorated.

In the prior art 3, the iron group metal compound is deposited on the surface of the sintered material by one kind of chemical vapor deposition, so it takes time to completely fill the entire gap from the surface to the inside of the sintered material. , The efficiency of modeling work is reduced. A device or the like for maintaining the region for irradiating the laser beam in a specific gas atmosphere is required, which makes the device structure complicated and expensive. As a method of filling the gaps and voids of the modeled object, a method of melting and impregnating a metal or resin can be considered.

However, the resin has a problem in strength and durability and cannot be applied to the above-mentioned molding die. In the case of using a metal, when the molten high-temperature metal comes into contact with the modeled object, a part of the modeled object may be melted or thermally deformed. The problem to be solved by the present invention is to solve the problems of the prior art in the technology for producing a three-dimensional shaped object by laminating the above-mentioned powdered optical laser-cured layer, and to provide a dense and highly accurate object Is to be obtained easily and efficiently.

[0009]

[Other technical matters ]

The powder material may have a spherical shape or a substantially spherical shape, and have an average particle diameter of 0.1 to 200 μm. The thickness can be preferably 1 to 100 μm, more preferably 5 to 50 μm.

The iron-based powder may be contained in an amount of 70 to 95% by weight. The iron-based powder may be a good hardenability material having a hardness of 400 or more Vickers hardness or 40 or more Rockwell hardness when quenched. The iron-based powder may be an alloy tool steel material. The non-ferrous powder may include a copper alloy made of an alloy of copper and phosphorus or manganese.

The non-ferrous powder may include a nickel alloy composed of an alloy of nickel and one or more materials selected from the group consisting of chromium, phosphorus and silicon. The iron-based powder may include chromium molybdenum steel, and the non-ferrous-based powder may include either phosphorous copper or manganese copper and nickel. The powder material may include 70 to 90% by weight of chromium molybdenum steel, 5 to 30% by weight of phosphorous copper or manganese copper, and 0 to 10% by weight of nickel.

The powder material may further include an anti-agglomeration agent. The anti-agglomeration agent may be coated on the surface of the powder material. The anti-aggregation agent can be a fatty acid. The powder material may have an average particle size of 1 to 20 μm.

[Method for Producing Three-dimensional Shaped Object] A method for producing a molded article having a desired three-dimensional shape by irradiating a powder material with a light beam to form a cured layer, and stacking the cured layers. The method includes the step (a) of impregnating a shaped article manufactured from the powder material with an impregnating material made of a metal having a melting point lower than that of the shaped article.

The impregnating material can be copper or a copper alloy. In the step (a), the impregnated material can be impregnated with the powder of the impregnating material in contact with the shaped article under reduced pressure in an inert or reducing atmosphere. The impregnating material can be bronze. The impregnating material may be an alloy of copper and tin, phosphorus, and manganese.

After the step (a), a step (b) of subjecting the shaped article to electrical discharge machining can be further included. [Three-dimensional shape-molded article] A three-dimensional shaped article manufactured by the above-described manufacturing method can be a plastic injection molding die or an electric discharge machining electrode.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Basic Manufacturing Process] FIG. 1 shows a basic manufacturing process. As shown in FIG. 1 (a), a molding table 1 that can be raised and lowered is placed inside a molding frame 10 surrounded by the periphery.
Equipped with 2. A mounting plate 14 for mounting and handling a modeled object is arranged on the modeling table 12.

Inside the molding frame 10 and on the mounting plate 14,
A plurality of cured layers 32 that have already been manufactured are stacked. The uncured powder material 30 is present around the hardened layer 32. By adjusting the upper and lower positions of the modeling table 12, the surfaces of the hardened layer 32 and the uncured powder material 30 are positioned so as to be slightly lower than the upper end of the modeling frame 10.
The distance between the shaping frame 10 and the surface of the hardened layer 32 determines the thickness of the hardened layer 32 to be produced next.

New powder material 30 is supplied on the hardened layer 32 and the uncured powder material 30 formed previously, and the plate-shaped regulating member 16 that traverses the frame 10 is formed.
The powder material 30 is moved in the horizontal direction at a position slightly higher than that to regulate the height position of the powder material 30 to form a layer of the powder material 30 having a constant thickness as a whole. As shown in FIG. 1 (b), when the surface of the powder material 30 inside the molding frame 10 is irradiated with the beam-shaped laser beam 50, all or part of the powder material in that portion is melted and the powder materials are integrated with each other. Are joined together to form a new hardened layer 32. When the powder material is melt-cured, it is joined and integrated with the previously formed hardened layer 32. Therefore, the newly formed hardened layer 32 is integrated with the lower hardened layer 32. Become.

By scanning the laser beam 50 in the horizontal direction, the hardened layer 32 having a predetermined pattern is obtained. By repeating the above steps, a three-dimensional shaped object in which a plurality of hardened layers 32 having a predetermined pattern shape are stacked is obtained. The uncured powder material 30 remains around the hardened layer 32, that is, around the shaped object.

As shown in FIG. 1C, if the molded article M is taken out together with the placing plate 14 from the inside of the molded frame 10, the molded article M having a three-dimensional shape can be obtained. [Powder Material] The powder material is a combination of a material that serves as a base that determines the basic structure and characteristics of a modeled object and a material that serves as a binder for joining the base material.

A material having a high hardness is preferable as the base material. When the molded product is used for applications requiring durability such as molding dies and electrodes for electrical discharge machining, considering the life of the product, the molded product requires high hardness and It is desirable to use a material having a high hardness. When a material with good hardenability is used as the base material, when sintering and shaping are performed by light irradiation, quenching is performed by heating during light irradiation and subsequent quenching, and characteristics such as hardness are improved. To do.

Iron-based powder is used as a material suitable for the base material. From the viewpoints of hardness and hardenability described above, the alloy tool steel material is preferable. Specifically, there is chrome molybdenum steel (for example, SCM440).
It is preferable that the binder material has a good compatibility with the base material (it is easy to form an alloy) and has a good fluidity when melted.

Specifically, nickel and nickel-based alloys which are compatible with iron-based materials are mentioned, and they also have a function of improving toughness, strength, corrosion resistance and the like and lowering the linear expansion coefficient. As the nickel alloy, an alloy with chromium, phosphorus, silicon or the like can be used. The Ni-P alloy has a melting point lower than that of the iron-based material (SCM steel) by 500 ° C. or more, and thus has an excellent function as a binder.

Copper and copper-based alloys are also compatible with iron-based materials, have good fluidity and wettability, and have a melting point of 300 ° C. as compared with iron-based materials.
Since the above is also low, the binder function is high when the iron-based material is sintered by light irradiation to be shaped. When an alloy of copper and phosphorus or manganese is used as the copper-based alloy, the melting point is lower than that of the iron-based material by 500 ° C. or more, and the above-mentioned function is excellent.

The larger the proportion of the binder material in the powder material, the more the low energy light beam can be sintered.
Sinterability by light irradiation is improved. However, if the proportion of the binder material is high, the melting point of the shaped article decreases. for that reason,
It becomes difficult to impregnate the shaped article with metal. The ratio of the binder material is determined in consideration of these conditions. When impregnating a molded article with a metal or the like after manufacturing, the melting point of the molded article needs to be set higher than that of the impregnated material. When the impregnating material is bronze or a copper alloy, the powder material for producing the shaped article preferably contains iron-based powder having a high melting point in the range of 70 to 95% by weight.

Specifically, a powder material having the following composition can be used.

[0027]

[Table 1] In the above table, manganese steel (SCM440) is JI
It is a material specified by the S standard and has the following composition.

[0028]

<Table 2><Component ratio of SCM440> ───────────────────────────────── Component Fe Cr Cr Ni Mo Mn Si C ───────────────────────────────── Ratio (wt%) Remainder 1.11 0.16 0.24 0.68 0.33 0.39 ──── ───────────────────────────── In addition, phosphorus copper containing 6.5 wt% phosphorus (P) is used. I was there.

A powder material having the following compositional composition can also be used.

[0030]

[Table 3] Here, the Ni-P-based alloy is an alloy composed of C: 0.09% by weight, P: 11.0% by weight, and the balance Ni.

[Particle Size of Powder Material] As the particle size of the powder material is smaller, the thickness of the powder material layer when deposited can be reduced, and the dimensional accuracy of the modeled object can be improved. However, powder with a small particle size has a large surface area and is prone to agglomeration, making it difficult for the powder to spread evenly even if sprinkled, and the packing density of the powder material in the powder material layer decreases. To do. It becomes difficult to form a thin powder material layer. The more small powders are present, the more pronounced the above problem.

Considering these conditions, the average particle size of the powder material is preferably 0.1 to 200 μm. Further, as a result of repeating the experiment under various conditions, the most preferable particle size range for practical use was an average particle diameter of 5 to 50 μm. [Modeling Conditions] As the light beam 50, a pulse YAG laser is used. The irradiation energy is set to 0.1 J / shot, the number of shots is 150 pps, the laser scanning speed is 50 mm / sec, and the scanning interval is 0.2 mm. As the light beam, a CW (continuous wave) YAG laser, a pulse carbon dioxide laser, or a CW carbon dioxide gas laser can also be used.

The modeling atmosphere is an inert gas atmosphere of nitrogen gas. The thickness of the powder material layer 30 to be laminated and hardened is set to 0.05 mm. The layer thickness can be set to 0.1 mm or 0.2 mm, but it is preferably as thin as possible in order to improve the dimensional accuracy of the modeled object.
In addition, a laminated thickness smaller than the particle size of the powder material cannot be formed.

As the mounting plate 14 for forming the hardened layer 32,
Materials such as die steel, high-speed steel, and cemented carbide that have a hardness higher than that of the modeled object are used. When the powder materials (1) and (2) described above were used to perform modeling under the above processing conditions, good molded products were obtained with any composition. The melting point of the modeled object manufactured using the powder material (1) is 115.
It was 0 ° C or higher.

[Agglomeration Prevention Agent] By using an aggregation prevention agent, it is possible to prevent the powder material from aggregating, facilitate the formation of the powder material layer, and improve the powder packing density. As the agglomeration inhibitor, various materials generally used as an agglomeration inhibitor can be used as long as they have a function of preventing the agglomeration of fine powder. Specifically, a compound containing a fatty acid such as stearic acid can be used.

Powdered or flake zinc stearate can be used. Most of the zinc stearate mixed with the powder material evaporates during sintering by light irradiation. A part of zinc stearate reacts with the iron-based material to exert a carburizing function and has an effect of improving hardness. It can be presumed that this carburizing function is caused by the reaction of carbon in the fatty acid containing the anti-agglomeration agent with the iron-based powder by light irradiation.

However, since the anti-agglomeration agent has an effect of inhibiting the sintering, that is, the binding of the powder material, if the blending amount is too large, the modeling density decreases, the modeling strength decreases, and a metal is added to the modeled object. When impregnated, there is a problem that the shape collapses.
The addition amount of the aggregation inhibitor is determined in consideration of these conditions. Specifically, about 0.5 to 1.0% by weight can be blended.

The specific composition of the powder material containing the agglomeration inhibitor is shown below.

[0039]

[Table 4] The powder material (3) has a smaller average particle size than the powder materials (1) and (2), but since it contains the agglomeration inhibitor, no problem occurs in forming the powder material layer. The use of powder having a small particle size makes it possible to form a thin powder material layer, that is, a hardened layer. In this case, for example, a powder material layer having a thickness of about 0.03 mm can be formed.

The anti-agglomeration agent may be coated on the surfaces of the iron-based powder and the non-ferrous powder constituting the powder material. Specific examples of the powder material coated with the agglomeration inhibitor are shown below.

[0041]

[Table 5] When the anti-agglomeration agent is coated on the powder material rather than being mixed with the anti-agglomeration agent, the anti-aggregation function is enhanced, and the powder material layer can be formed more favorably.

[Impregnation Treatment of Modeled Object] As the impregnating material, a material that can be melted while being in contact with the surface of the modeled object and filled with fine gaps or pores existing in the modeled object to be impregnated Is used. As the impregnating material, a material having a melting point lower than that of the modeled object is used. A material having good fluidity when melted is preferable.

The impregnating material affects the mechanical properties of the shaped article. Select the impregnating material according to the intended use and required performance of the modeled object. Usually, it is used by selecting from the same metals as those used for powder materials. Copper or a copper alloy can be used as a specific example of the impregnating material. As the copper alloy, an alloy of copper and tin, phosphorus, manganese, or the like can be used. More specifically, bronze can be used.

For example, the molded article manufactured by using the above-mentioned powder material (1) has a melting point of 1150 ° C. or higher, so copper having a melting point of about 1084 ° C. can be preferably used. In the impregnation treatment, the molded article is impregnated by melting the impregnated material while the impregnated material is in contact with the surface of the molded article.
By performing the impregnation treatment under reduced pressure, due to the action of capillary phenomenon,
The impregnation material is efficiently infiltrated into the shaped article.

If the treatment atmosphere is an inert atmosphere, the molded article or impregnated material is unlikely to be oxidized. If the treatment atmosphere is a reducing atmosphere, even if some oxidation occurs during or after modeling, the surface is reduced and activated at the same time as the impregnation treatment, and the impregnation material penetrates well into the interior. If a powdery impregnated material is used, the work of arranging it on the surface according to the shape of the modeled object is easy. The amount used for the impregnation treatment can be easily changed. Melting during the impregnation treatment is also easy. It can easily penetrate into the gaps of the shaped object.

Specific treatment conditions for the impregnation treatment are shown below. Processing equipment: Vacuum furnace Impregnation material: Copper powder. Placed on the model so that it contacts the surface. Processing temperature: 1150 ° C. Processing pressure: 133 Pa (1 Torr) Processing atmosphere: Hydrogen (reducing gas) about 5 liters / min
Supplied by. When a molded article was manufactured using the above-mentioned various powder materials (1) to (4) and impregnated under the above conditions, the surface roughness was small, the strength was excellent, and the thermal conductivity was in each case. I was able to obtain a high product.

The impregnating material is bronze (70Cu-30S).
n), instead of the powder material (1)
When the same impregnation treatment as described above was performed, a treated product having excellent quality performance was obtained in the same manner as above. In this case, the melting point of the modeled object is 1150 ° C, and the melting point of the impregnated material is 800 ° C or less. Therefore, by decreasing the blending ratio of the iron-based powder of the powder material (1) and increasing the non-ferrous powder of the binder material,
Even if the melting point is lowered a little, the impregnation treatment can be sufficiently performed.

The impregnating material is copper copper (P = 6.5% by weight)
When the same treatment was performed instead of the above, the same excellent performance as described above could be exhibited. The melting point of phosphorous copper is 850 ° C. or lower. Therefore, also in this case, the mixing ratio of the iron-based powder of the powder material (1) can be reduced. By the impregnation treatment described above, the surface roughness of the modeled object becomes good (small). By filling the gaps and pores of the modeled object with the impregnating material, the thermal conductivity increases. Strength is also improved.

[Electric Discharge Machining] The shaped article shaped and impregnated as described above can be finished by electric discharge machining. As the apparatus and processing conditions used for electric discharge machining, the same apparatus and processing conditions as those for the processing for ordinary metal materials can be applied.

For electric discharge machining, there is a method in which an electrode having a shape corresponding to the machining shape is used and machining is performed in accordance with the shape of the electrode. In this case, the processing speed becomes slow and it takes time to manufacture the electrode. The following method can be adopted when it is sufficient to shape the surface shape or form small unevenness on a three-dimensionally shaped object in advance.

As shown in FIG. 2, an electrode 60 having a rectangular rod shape.
By moving the tip of the object along the surface of the modeled article M, the surface of the modeled article M can be scraped off to finish the surface shape of the modeled article M. The residue of the metal powder adhering to the surface of the molded article M is removed, a shape part which is difficult to be formed by light irradiation modeling is formed, or holes, grooves, and depressions are partially formed on the surface of the molded article M. It is effective when producing the above.

As the electrode 60, in addition to the square bar-shaped one,
A circular bar shape or other relatively simple bar shape or other three-dimensional shape can be used. Since the above method only scrapes off a part of the molded article M, it has high processing efficiency and can finish in a short time. Further, it is possible to take advantage of the fact that high aspect machining, which is an advantage of electric discharge machining, is possible.

Particularly, in the molding method using the powder material, since unnecessary metal powder is likely to remain attached to the surface of the molded article M, the surface is smooth and the surface is roughened by the removal processing of the unnecessary metal powder by electric discharge machining. It is possible to efficiently obtain a small shaped object. [Three-dimensional shaped article] Using the powder material of the present invention, the shaped article produced by the production method of the present invention has high hardness, excellent mechanical strength, and advantages such as small surface roughness. It is excellent as a mold for plastic injection molding and an electrode for electric discharge machining.

In these applications, it is required to have a complicated three-dimensional shape with high dimensional accuracy, and it is required to quickly respond to a design change. Therefore, the light irradiation scanning pattern is changed. The above-mentioned method, in which the shape of the modeled article can be changed by itself and the molded article can be processed at high speed, is extremely effective.

[0055]

EFFECTS OF THE INVENTION The powder material for producing a three-dimensional shaped object according to the present invention has a high hardness and a high mechanical strength and durability by combining a non-ferrous powder serving as a binder based on the iron powder. It is possible to provide a molded article having excellent properties. Moreover, by impregnating the molded article with the impregnating material,
It is possible to fill the gaps and voids formed on the surface of the modeled object to obtain a modeled object having a small surface roughness.

At the time of the impregnation treatment, the shaped article based on the iron-based powder, which has a melting point much higher than that of the metal to be impregnated, does not partially melt or undergo thermal deformation and is shaped. The formed three-dimensional shape can be accurately maintained. As a metal to be impregnated, a material having a relatively high melting point can be used, and durability and mechanical characteristics during use can be improved. The impregnation material can be impregnated at a high temperature where the fluidity of the impregnation material is improved, and the impregnation material can quickly and sufficiently penetrate into the gaps and pores inside the modeled object.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing stepwise a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an electric discharge machining process.

[Explanation of symbols]

10 modeling frame 12 modeling table 14 Placement plate 16 Regulation plate 30 powder material 32 hardened layer 50 laser light 60 EDM electrode

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Abe 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Masataka Takenami, 1048, Kadoma, Kadoma City, Osaka Matsushita Electric Works, Ltd. ( 56) References JP-A-3-183530 (JP, A) JP-A-4-193929 (JP, A) JP-A-1-96353 (JP, A) JP-A-3-24205 (JP, A) Hei 5-148511 (JP, A) JP 2000-73108 (JP, A) JP-B 3-50823 (JP, B2) Patent 2620353 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , (DB name) B22F 1/00-7/08 B29C 67/00-67/24 B23K 26/00-26/18

Claims (9)

(57) [Claims] 1. A powder material by irradiating a light beam to form a cured layer, a powder material used in the method for producing a molded article having a desired three-dimensional shape by stacking the cured layer, a chromium molybdenum Iron-based powder consisting of steel 70-90% by weight
And non-ferrous powder consisting of copper copper or manganese copper 5 to 30 times
A powder material for producing a three-dimensional shaped object, which comprises the amount of 0% to 0% to 10% by weight of non-ferrous powder made of nickel . 2. 10% by weight of non-ferrous powder made of nickel
For manufacturing a three-dimensional shaped object according to claim 1, including:
Powder material. Wherein the powder material forms a spherical or substantially spherical, claim 1 and the average particle size of 0.1~200μm
Is a powder material for producing a three-dimensional shaped object according to 2 . 4. A powder material for three-dimensionally shaped object manufactured according to any one of claims 1 to 3, further comprising a deflocculating agent in the powder material. 5. The powder material for producing a three-dimensional shaped article according to claim 4 , wherein the anti-agglomeration agent is coated on the surface of the powder material. Wherein said anti-agglomerating agent, according to claim 4 which is a fatty acid
Or the powder material for producing the three-dimensional shaped object according to 5 . Wherein said powder material is powder material for three-dimensionally shaped object manufactured according to the average particle diameter of any of claims 4-6 is 1 to 20 [mu] m. 8. A method for forming a hardened layer by irradiating a powder material with a light beam, and stacking the hardened layers to produce a molded article having a desired three-dimensional shape. method for producing a three-dimensionally shaped object Ru powder material der according to any one of 1-7. 9. Manufactured according to the method of claim 8, Chromium-molybdenum steel 70-90% by weight and phosphorous copper or
Manganese copper 5-30% by weight, nickel 0-10% by weight
Three-dimensional shape modeling in which hardened layers including
object.