JP7395840B2 - Powder for additive manufacturing and method for producing additively manufactured objects - Google Patents

Description

The present invention relates to a powder for layered manufacturing and a method for producing a layered object.

BACKGROUND ART In recent years, additive manufacturing using metal powder has become popular as a technology for modeling three-dimensional objects. This technology is based on the process of calculating the cross-sectional shape of a three-dimensional object when sliced thinly on a plane perpendicular to the stacking direction, the process of layering metal powder to form a powder layer, and the shape determined by calculation. This is a technique for modeling a three-dimensional object by repeating the step of forming a powder layer and the step of solidifying a portion of the powder layer.

Known methods for modeling three-dimensional objects include fused deposition molding (FDM), selective laser sintering (SLS), and binder jetting, depending on the solidification principle. ing.

Patent Document 1 discloses a modeling powder used in the additive manufacturing method, which is made of a powder containing ceramics and/or metal and a binder, and has an angle of repose of 16° or more and 43° or less. . Since such powder has appropriate fluidity, it is possible to form a powder layer with a constant thickness when moving the modeling powder using a blade, roller, etc. Make it.

JP2017-127997A

On the other hand, in the modeling powder described in Patent Document 1, ceramic powder or metal powder is granulated by a granulation method such as a spray drying method, or mixed with a binder dissolved in a solvent to achieve the desired object. Achieving liquidity. In other words, it can be said that by adding a relatively large amount of binder of 10% by volume or more, the secondary shape of the powder is adjusted and the fluidity is controlled. Therefore, when firing the obtained shaped article, it is necessary to remove a large amount of the binder used to form the secondary shape, and the density of the shaped article tends to decrease accordingly.

The additive manufacturing powder according to the application example of the present invention is
A powder for additive manufacturing used in an additive manufacturing method,
A metal powder having an average particle size of 1.0 μm or more and 15.0 μm or less, when the particle size D50 when the cumulative volume based on volume is 50% from the small diameter side is the average particle size;
Ceramic powder containing surface-treated ceramic particles and having an average particle size of 3.0 nm or more and 100.0 nm or less,
including;
The additive manufacturing method is a binder jetting method,
The ceramic particles subjected to the surface treatment have a particle main body and a vinyl group, phenyl group, acrylic group or methacrylic group provided on the surface of the particle main body,
The average particle size of the ceramic powder is 0.0005 or more and 0.0100 or less, when the average particle size of the metal powder is 1,
A mixing ratio of the ceramic powder to the metal powder is 0.005% by mass or more and 0.100% by mass or less.

It is a process chart showing a manufacturing method of a layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure for explaining the manufacturing method of the layered object concerning an embodiment. It is a figure showing the concept of powder for additive manufacturing concerning an embodiment. FIG. 2 is a cross-sectional view showing the concept of ceramic particles subjected to surface treatment.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiments of the powder for layered manufacturing, the layered object, and the method for manufacturing the layered object of the present invention will be described in detail based on the accompanying drawings.

1. Method for manufacturing a laminate-molded object First, a method for manufacturing a laminate-molded object according to an embodiment will be described.

FIG. 1 is a process diagram showing a method for manufacturing a layered product according to an embodiment. FIGS. 2 to 10 are diagrams for explaining the method for manufacturing a layered product according to the embodiment, respectively.

The method for producing a layered object according to the embodiment is a method using a layered manufacturing method called a binder jetting method, as an example, and as shown in FIG. A step S02 of supplying a binder solution to a predetermined region of the first powder layer 31 to bind the particles in the first powder layer 31 to obtain a first bound body 41; A step S03 of spreading new additive manufacturing powder 1 on the first powder layer 31 including the binder 41 to form the second powder layer 32, and supplying the binder solution 4 to a predetermined area of the second powder layer 32. and step S04 of binding the particles in the second powder layer 32 to obtain a second bound body 42. The method for producing a laminate-molded body includes a step S05 of obtaining a molded body 5 by repeating steps S03 and S04 once or twice or more, and a laminate-molded body which is a sintered body by firing the molded body 5. 10.
Each step will be explained in sequence below.

[1] First, prior to explaining step S01, the additive manufacturing apparatus 2 will be explained.
The additive manufacturing apparatus 2 includes an apparatus main body 21 having a powder storage section 211 and a modeling section 212, a powder supply elevator 22 provided in the powder storage section 211, a modeling stage 23 provided in the modeling section 212, and the apparatus main body 21. It includes a coater 24 and a solution supply section 25 that are movable above.

The powder storage portion 211 is a recessed portion provided in the device main body 21 and having an open top. Powder 1 for additive manufacturing is stored in this powder storage section 211 . Then, an appropriate amount of the layered manufacturing powder 1 stored in the powder storage section 211 is supplied to the modeling section 212 by the coater 24.

Furthermore, a powder supply elevator 22 is arranged at the bottom of the powder storage section 211. The powder supply elevator 22 is movable in the vertical direction in FIGS. 2 to 9 with the additive manufacturing powder 1 placed thereon. By moving the powder supply elevator 22 upward, the additive manufacturing powder 1 placed on the powder supply elevator 22 can be pushed up and protruded from the powder storage section 211. Thereby, the protruding portion of the layered manufacturing powder 1 can be moved toward the modeling section 212 as will be described later.

The shaped portion 212 is a recessed portion that is provided in the device main body 21 and is open at the top. In this modeling section 212, the powder 1 for additive manufacturing supplied from the powder storage section 211 is spread in a layered manner.

Furthermore, a modeling stage 23 is arranged at the bottom of the modeling section 212. The modeling stage 23 is movable in the vertical direction in FIGS. 2 to 9 in a state where the layered modeling powder 1 is spread. By appropriately setting the height of the modeling stage 23, the amount of the layered manufacturing powder 1 spread on the modeling stage 23 can be adjusted.

The coater 24 is provided so as to be movable in the left-right direction in FIGS. 2 to 9 from the powder storage section 211 to the shaping section 212. By dragging the powder 1 for additive manufacturing with the movement, the powder 1 for additive manufacturing can be spread on the modeling stage 23 in a layered manner.

The solution supply unit 25 is composed of, for example, an inkjet head or a dispenser, and is movable two-dimensionally in the left-right direction and the paper thickness direction in FIGS. 2 to 9 in the modeling unit 212. Then, the solution supply unit 25 can supply a target amount of binder solution 4 to a target position.

Next, process S01 using the above-mentioned layered manufacturing apparatus 2 will be explained.
First, as step S01, the layered modeling powder 1 is spread on the modeling stage 23 to form the first powder layer 31. Specifically, as shown in FIGS. 2 and 3, the coater 24 is used to drag the layered modeling powder 1 stored in the powder storage section 211 onto the modeling stage 23 to make it uniform in thickness. As a result, the first powder layer 31 shown in FIG. 4 is obtained. At this time, the thickness of the first powder layer 31 can be adjusted by lowering the upper surface of the modeling stage 23 slightly lower than the upper end of the modeling section 212. In addition, the powder for additive manufacturing 1 according to the present embodiment is a powder with high fluidity, although the average particle size of the metal powder 11 is small, as will be described later. Therefore, the first powder layer 31 with a high filling rate can be obtained.

[2] Next, as step S02, as shown in FIG. 5, the binder solution 4 is supplied to a desired region of the first powder layer 31 by the solution supply section 25. As a result, particles in the region of the first powder layer 31 to which the binder solution 4 has been supplied are bound together, and a first bound body 41 is obtained. The first bound body 41 is formed by binding particles of the additive manufacturing powder 1 with a binder, and has a shape retention property that is not broken by its own weight or more.

The binder solution 4 is not particularly limited as long as it is a liquid that has a component that has tackiness or adhesiveness that can bind the particles of the layered manufacturing powder 1 to each other. As an example, examples of the solvent of the binder solution 4 include water, alcohols, ketones, carboxylic acid esters, etc., and a mixed solution containing at least one of these may be used. In addition, examples of solutes in the binder solution 4 include fatty acids, paraffin wax, microwax, polyethylene, polypropylene, polystyrene, acrylic resin, polyamide resin, polyester, stearic acid, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), Examples include polyethylene glycol (PEG).

[3] Next, in step S03, a new additive manufacturing powder 1 is spread on the first powder layer 31 including the first bound body 41 to form a second powder layer 32. Specifically, as shown in FIG. 6, the coater 24 is used to drag the layered modeling powder 1 stored in the powder storage section 211 onto the modeling stage 23 to make it uniform in thickness. As a result, a second powder layer 32 shown in FIG. 7 is obtained. At this time, the thickness of the second powder layer 32 can be adjusted by lowering the upper surface of the first powder layer 31 and the upper surface of the first binding body 41 slightly lower than the upper end of the modeling section 212. I can do it.

[4] Next, as step S04, as shown in FIG. 8, the binder solution 4 is supplied to a desired region of the second powder layer 32 by the solution supply unit 25. As a result, particles in the region of the second powder layer 32 to which the binder solution 4 has been supplied are bound together, and a second bound body 42 is obtained. The second bound body 42 is formed by binding the particles of the layered manufacturing powder 1 with a binder, and has a shape retention property that is not broken by its own weight or more.

[5] Next, as step S05, by repeating step S03 and step S04 once or twice or more, the second binder 42 and the second binder 42 are formed on the first binder 41 and the second binder 42. One or more layers of similar binders are stacked. Thereby, as shown in FIG. 9, a molded body 5 having the desired shape is obtained. The molded body 5 is an aggregate of bound bodies including a first bound body 41 and a second bound body 42, and the powder 1 for additive manufacturing that did not constitute the molded body 5 is recovered. Note that this step may be performed as necessary, and may be omitted if the molded body 5 has been obtained at the stage of step S04.

[6] Next, in step S06, the molded body 5 is taken out from the shaping section 212 and fired in a firing furnace or the like. Thereby, as shown in FIG. 10, a laminate-molded body 10, which is a sintered body of the laminate-molded powder 1, is obtained.

When firing the molded body 5, the molded body 5 may be subjected to a degreasing treatment prior to firing. The degreasing process is a process in which at least a portion of the binder is removed by heating the molded body 5. Specifically, it is a process of heating the molded body 5, and an example of the heating conditions is a temperature of 100° C. or more and 750° C. or less x 0.1 hour or more and 20 hours or less. Furthermore, examples of the heating atmosphere include an air atmosphere, an inert gas atmosphere, and a reduced pressure atmosphere.

Furthermore, the firing process is a process in which the particles of the metal powder 11 are sintered together by heating the compact 5 or the compact 5 that has been subjected to the degreasing process. An example of the heating conditions is 980° C. or higher and 1330° C. or lower x 0.2 hours or more and 7 hours or less. Furthermore, examples of the heating atmosphere include an air atmosphere, an inert gas atmosphere, and a reduced pressure atmosphere.

As described above, the method for producing a laminate manufactured body according to the present embodiment includes the step S05 of obtaining a molded body 5 by the laminate manufacturing method using the powder 1 for laminated manufacturing, and the step of firing the molded body 5 to form a sintered body. It has a step of obtaining a certain laminate-molded body 10.

According to such a manufacturing method, even though the average particle size of the metal powder 11 is small, a highly fluid powder is used as the additive manufacturing powder 1, so that molding with a high filling rate of the additive manufacturing powder 1 is possible. body 5 can be manufactured. In other words, since it is not necessary to use a large amount of binder to improve fluidity, the ratio of binder in the molded body 5 can be kept low. As a result, it is possible to finally obtain a laminate-molded body 10 with high density and excellent mechanical properties.

2. Powder for additive manufacturing Next, powder for additive manufacturing according to an embodiment will be described.
FIG. 11 is a diagram showing the concept of the additive manufacturing powder according to the embodiment.

The additive manufacturing powder 1 according to the present embodiment is a powder used in various additive manufacturing methods such as the binder jetting method described above, and as shown in FIG. 11, it includes a metal powder 11, a ceramic powder 12, It is a mixed powder containing. Among these, the average particle size of the metal powder 11 is 0.5 μm or more and 30.0 μm or less. Further, the average particle size of the ceramic powder 12 is 3.0 nm or more and 100.0 nm or less. The mixing ratio of ceramic powder 12 to metal powder 11 is 0.005% by mass or more and 0.100% by mass or less.

Such a powder for additive manufacturing 1 is a powder that has high fluidity and fillability even though the average particle size of the metal powder 11 is small. For this reason, even when moving the layered manufacturing powder 1 by dragging it with the coater 24 as in step S01 and step S03 in the manufacturing method described above, the desired amount can be moved smoothly. The first powder layer 31 and the second powder layer 32 formed by smoothing the layered manufacturing powder 1 by the coater 24 have a high particle filling rate. In other words, there is no need to perform granulation or the like using a large amount of binder in order to improve fluidity. Therefore, in the molded body 5 as well, it is possible to increase the filling rate of the powder for layered manufacturing 1 and to decrease the content rate of the binder. As a result, it is possible to increase the density of the layered product 10 finally obtained. Moreover, since the shape retention of the molded body 5 also becomes high, the dimensional accuracy of the layered body 10 can also be improved.

That is, the laminate-molded body 10 according to the present embodiment includes a sintered body in which the laminate-molded powder 1 having excellent fluidity and fillability is sintered without using a large amount of binder. For this reason, the laminate-molded body 10 has a high density. Note that the laminate-molded body 10 may include parts other than the sintered body of the laminate-molded powder 1. For example, the additively manufactured body 10 is a composite of a sintered body of the additively manufactured powder 1 according to the present embodiment and a sintered body of a powder different from the sintered body of the additively manufactured powder 1. There may be.

One of the reasons why the fluidity of the additive manufacturing powder 1 is high is that the particles of the ceramic powder 12 having a relatively small diameter are interposed between the particles of the metal powder 11 having a relatively large diameter. , aggregation of particles of the metal powder 11 may be suppressed. By suppressing agglomeration, the number of aggregated particles that obstruct the flow of the layered manufacturing powder 1 is reduced, so it is thought that the fluidity of the layered manufacturing powder 1 can be improved. Further, since the ceramic powder 12 has a relatively small diameter and the mixing ratio is kept low, even if the ceramic powder 12 is mixed, it is unlikely to have an adverse effect on the sintering of the metal powder 11. For these reasons, the mechanical strength of the finally obtained layered product 10 can be increased.

Note that when the average particle size of the metal powder 11 is less than the lower limit value, aggregation of particles of the metal powder 11 becomes unavoidable, and manufacturing of the metal powder 11 becomes difficult. On the other hand, if the average particle size of the metal powder 11 exceeds the upper limit, the filling properties of the metal powder 11 will decrease, making it difficult to increase the density of the finally obtained layered product 10.

Moreover, if the average particle size of the ceramic powder 12 is less than the lower limit value, it becomes difficult to manufacture the ceramic powder 12. On the other hand, if the average particle size of the ceramic powder 12 exceeds the upper limit, the ceramic powder 12 may have an adverse effect on the sintering of the metal powder 11.

Furthermore, if the mixing ratio of the ceramic powder 12 is below the lower limit value, the effect of adding the ceramic powder 12 will not be obtained. On the other hand, if the mixing ratio of the ceramic powder 12 exceeds the upper limit value, the relative amount of the ceramic powder 12 increases, so that the ceramic powder 12 may have an adverse effect on the sintering of the metal powder 11.

Note that additives other than the metal powder 11 and the ceramic powder 12 may be added to the additive manufacturing powder 1. Examples of additives include resin powder, resin fibers, surfactants, and lubricants. Furthermore, impurities that are unavoidably mixed may be included. However, the total amount of additives added and the amount of impurities mixed is preferably 1.0% by mass or less, more preferably 0.5% by mass or less.

Further, the content of the metal powder 11, which is the balance of the ceramic powder 12, additives, and impurities, is preferably 98% by mass or more, and more preferably 99% by mass or more, as an example. As a result, the finally obtained layered product 10 is dominated by a sintered body of the metal powder 11. Therefore, a layered product 10 having good mechanical properties derived from the metal sintered body can be obtained.

Further, the average particle size of the metal powder 11 is preferably 0.5 μm or more and 15.0 μm or less, more preferably 1.0 μm or more and 8.5 μm or less.

Furthermore, the average particle size of the ceramic powder 12 is preferably 3.0 nm or more and 15.0 nm or less, more preferably 5.0 nm or more and 10.0 nm or less.

Further, the mixing ratio of the ceramic powder 12 is preferably 0.005% by mass or more and 0.050% by mass or less, more preferably 0.010% by mass or more and 0.030% by mass or less.

By satisfying the above ranges, the powder for layered manufacturing 1 becomes a powder that can produce a layered object 10 with particularly high density and good mechanical properties.

Further, the average particle size of the ceramic powder 12 is preferably 0.0005 or more and 0.0100 or less, and preferably 0.0010 or more and 0.0050 or less, when the average particle size of the metal powder 11 is 1. More preferred. This makes it possible to optimize the balance in average particle size between the metal powder 11 and the ceramic powder 12. As a result, the density of the finally obtained laminate-molded body 10 can be particularly increased.

Note that the above-mentioned average particle size refers to the particle size D50 when the cumulative volume based on volume is 50% using a laser diffraction particle size distribution measuring device. Further, the mixing ratio of the ceramic powder 12 refers to the mass ratio of the ceramic powder 12 to the metal powder 11.

The constituent material of the metal powder 11 is not particularly limited, and may be any material as long as it has sinterability. Examples include simple substances such as Fe, Ni, Co, and Ti, alloys containing these as main components, intermetallic compounds, and the like.

Among these, Fe-based alloys include stainless steels such as austenitic stainless steels, martensitic stainless steels, and precipitation hardening stainless steels, low carbon steels, carbon steels, heat-resistant steels, die steels, and high-speed tool steels. , Fe-Ni alloy, Fe-Ni-Co alloy, etc.

Furthermore, examples of the Ni-based alloy include Ni-Cr-Fe-based alloy, Ni-Cr-Mo-based alloy, Ni-Fe-based alloy, and the like.

Furthermore, examples of Co-based alloys include Co--Cr-based alloys, Co--Cr--Mo-based alloys, and Co-Al-W-based alloys.

Examples of Ti-based alloys include alloys of Ti and metal elements such as Al, V, Nb, Zr, Ta, and Mo. Specifically, Ti-6Al-4V, Ti-6Al- 7Nb etc. are mentioned.

The metal powder 11 may be manufactured by any method, but it is preferably a powder manufactured by an atomization method such as a water atomization method, a gas atomization method, or a high-speed rotation water jet atomization method. Preferably, the powder is produced by an atomization method or a high-speed rotating water jet atomization method. Even if these powders have a small average particle size, they can be manufactured at low cost and are therefore useful as the metal powder 11.

Furthermore, the metal powder 11 may be subjected to various pretreatments such as heat treatment, plasma treatment, ozone treatment, and reduction treatment.

Furthermore, when D10 is the particle size when the cumulative volume based on the volume of the metal powder 11 is 10% from the small diameter side, the particle size D10 is preferably 1.0 μm or more and 10.0 μm or less. Further, when the particle size when the cumulative volume is 90% from the small diameter side is defined as D90, the particle size D90 is preferably 3.0 μm or more and 50.0 μm or less.

Further, the constituent materials of the ceramic powder 12 are not particularly limited, but examples include oxide ceramics such as silicon oxide, magnesium oxide, calcium oxide, aluminum oxide, titanium oxide, zirconium oxide, boron oxide, and yttrium oxide, and nitride ceramics. Examples include non-oxide ceramics such as silicon, aluminum nitride, boron nitride, titanium nitride, silicon carbide, boron carbide, titanium carbide, and tungsten carbide.

Among these, the main material of the ceramic powder 12 is preferably silicon oxide. The ceramic powder 12 mainly composed of silicon oxide has a small effect on the sinterability of the metal powder 11, and has a large effect of increasing the fluidity of the additive manufacturing powder 1. Another advantage is that ceramic powder 12 with uniform particle size can be easily manufactured at low cost.
Note that silicon oxide includes both silicon monoxide and silicon dioxide.

Further, the ceramic powder 12 may include ceramic particles that are not surface-treated, but preferably include ceramic particles 120 that have been surface-treated. Thereby, the surface of the ceramic particles 120 can be modified to be hydrophobic, for example. As a result, moisture is less likely to be adsorbed onto the surface of the ceramic particles 120, and aggregation of the ceramic particles 120 can be suppressed. In addition, it is possible to suppress a decrease in fluidity of the additive manufacturing powder 1 due to aggregation of the ceramic particles 120.

FIG. 12 is a cross-sectional view showing the concept of ceramic particles 120 that have been subjected to surface treatment.

Ceramic particles 120 shown in FIG. 12 have a particle main body 121 and a modified layer 122 provided on the surface of the particle main body 121. The particle body 121 is made of the above-mentioned ceramic material, and the modified layer 122 is a layer containing, for example, a surface modification group that imparts various properties in addition to the above-mentioned hydrophobic property. Examples of this surface modification group include vinyl group, phenyl group, alkyl group, acrylic group, methacryl group, and trialkylsilyl group. Among these, a vinyl group, a phenyl group, or an alkyl group is preferably used as the surface modification group, and a vinyl group is particularly preferably used. By adding these surface modification groups to the surface of the particle body 121, aggregation of the ceramic particles 120 is suppressed, so the ceramic particles 120 are interposed between the particles of the metal powder 11, and the particles of the metal powder 11 are Aggregation between them is also suppressed. As a result, even when the average particle size of the metal powder 11 is small, the fluidity of the additive manufacturing powder 1 can be improved.

Note that the number of carbon atoms in the alkyl group is preferably 1 or more and 6 or less. Moreover, it is more preferable that the alkyl group is a methyl group. Similarly, among the trialkylsilyl groups, the number of carbon atoms in each of the three alkyl groups bonded to the silicon atom is preferably 1 or more and 6 or less. Moreover, it is more preferable that the trialkylsilyl group is a trimethylsilyl group.

Moreover, the method of imparting the surface modification group is not particularly limited as long as it is a method of modifying the surface of the ceramic with a functional group. For example, a method in which the particle body 121 is placed in a reaction tank, a compound containing a surface modification group is sprayed while stirring, and then heated; a method in which a compound containing a surface modification group is added to a dispersion containing the particle body 121 and heated Examples include a method of stirring while stirring. By such a method, a modified layer 122 containing a surface modification group can be formed on the surface of the particle body 121.

Furthermore, the ceramic powder 12 may be subjected to various pretreatments such as heat treatment, plasma treatment, and ozone treatment.

Further, the layered manufacturing powder 1 according to the present embodiment can also be used in layered manufacturing methods other than the binder jetting method described above. Specifically, the powder for additive manufacturing 1 may be used in a hot fusion deposition method, a powder sintering additive manufacturing method, or the like. In these methods, the layered manufacturing powder 1 can be irradiated with a laser or an electron beam in the modeling section 212 to be sintered. Thereby, the laminate-molded object 10 can be manufactured in the modeling section 212.

As mentioned above, the powder for additive manufacturing, the additive manufacturing object, and the manufacturing method of the additive manufacturing object of the present invention have been explained based on the illustrated embodiments, but the invention is not limited thereto, and for example, the additive manufacturing powder of the invention The powder for use may be one in which any component is added to the above embodiment.

Next, specific examples of the present invention will be described.
1. Production of powder for additive manufacturing (Example 1)
First, SUS630 stainless steel powder manufactured by a water atomization method and silicon oxide powder were mixed for 5 minutes to obtain a powder for additive manufacturing. Note that a Dalton mixer was used for mixing. Further, the mixing conditions are as follows.

Average particle size of stainless steel powder: 3.75μm
Bulk density of stainless steel powder: 1.90g/ ^cm3
Tap density of stainless steel powder: 4.07g/ ^cm3
Mixing ratio of stainless steel powder: 100 parts by mass Average particle size of silicon oxide powder: 10 nm
Mixing ratio (ratio) of silicon oxide powder: 0.020 parts by mass (0.020 mass%)
Surface treatment of silicon oxide powder: Vinyl group modification

(Examples 2 to 23)
A powder for additive manufacturing was obtained in the same manner as in Example 1, except that the manufacturing conditions for the powder for additive manufacturing were changed as shown in Table 1.

In addition, "heating" shown in Table 1 refers to the process of heating at 200° C. for 50 hours in an air atmosphere using a dry oven after preparing the powder for additive manufacturing.

(Comparative Examples 1 to 6)
Powders for additive manufacturing were obtained in the same manner as in Examples 1 to 6, except that the addition of silicon oxide powder was omitted.

(Comparative Examples 7 to 9)
A powder for additive manufacturing was obtained in the same manner as in Example 1, except that the manufacturing conditions for the powder for additive manufacturing were changed as shown in Table 1.

2. Evaluation of powder for additive manufacturing 2.1 Bulk density The bulk density of the powder for additive manufacturing obtained in each example and each comparative example was measured by the metal powder apparent density measurement method specified in JIS Z 2504:2012. did.

2.2 Tap Density The tap density of the additive manufacturing powders obtained in each Example and each Comparative Example was measured using a powder characteristic evaluation device, Powder Tester (registered trademark) PT-X, manufactured by Hosokawa Micron Co., Ltd. . Note that the number of taps was 125.

2.3 Angle of Repose The angle of repose of the additive manufacturing powders obtained in each Example and each Comparative Example was measured using a powder property evaluation device, Powder Tester (registered trademark) PT-X, manufactured by Hosokawa Micron Co., Ltd. .

3. Evaluation of Laminate Molded Object A molded article was produced by laminating 50 layers of the powders for layered manufacturing obtained in each Example and each Comparative Example by a layered manufacturing method using a binder jetting method. A stearic acid emulsion was used as the binder solution.

Subsequently, the produced molded body was subjected to a degreasing treatment to be degreased, and then fired in a firing furnace. The firing conditions were 1300° C. for 3 hours in an argon atmosphere. As a result, a laminate-molded body, which is a sintered body, was obtained.

Next, the density of the obtained laminate-molded body was measured. Subsequently, the relative value of the measured density to the true density of the metal powder used, that is, the relative density was calculated. Then, the calculated relative values were evaluated in accordance with the following evaluation criteria.

(Evaluation criteria)
A: Relative density is 99.0% or more B: Relative density is 98.0% or more and less than 99.0% C: Relative density is 97.0% or more and less than 98.0% D: Relative density is 96.0% or more and less than 97.0% E: Relative density is 95.0% or more and less than 96.0% F: Relative density is less than 95.0%

As is clear from Table 1, by optimizing the average particle size D50 of the metal powder, the average particle size of the ceramic powder, and the mixing ratio of the ceramic powder, it is possible to finally manufacture a laminate with a high relative density. It was recognized that

It was also found that by adding a surface modification group to the particle surface of the ceramic powder, it was possible to improve the filling properties and fluidity of the powder for layered manufacturing and to increase the relative density of the layered product.

From the above, according to the present invention, it is possible to realize a powder for layered manufacturing that can produce a high-density layered object.

In addition, when the same evaluation as above was performed using SUS304L stainless steel powder and SUS316L stainless steel powder instead of SUS630 series stainless steel powder, the same tendency as that of SUS630 series stainless steel powder was observed.

DESCRIPTION OF SYMBOLS 1... Powder for additive manufacturing, 2... Additive manufacturing apparatus, 4... Binder solution, 5... Molded object, 10... Laminate manufacturing object, 11... Metal powder, 12... Ceramic powder, 21... Apparatus main body, 22... Powder supply elevator, 23... Modeling stage, 24... Coater, 25... Solution supply unit, 31... First powder layer, 32... Second powder layer, 41... First bound body, 42... Second bound body, 120... Ceramic particles, 121... Particle body, 122... Modified layer, 211... Powder storage section, 212... Modeling section, S01... Process, S02... Process, S03... Process, S04... Process, S05... Process, S06... Process

Claims (6)

A powder for additive manufacturing used in an additive manufacturing method,
A metal powder having an average particle size of 1.0 μm or more and 15.0 μm or less, when the particle size D50 when the cumulative volume based on volume is 50% from the small diameter side is the average particle size;
Ceramic powder containing surface-treated ceramic particles and having an average particle size of 3.0 nm or more and 100.0 nm or less,
including;
The additive manufacturing method is a binder jetting method,
The ceramic particles subjected to the surface treatment have a particle main body and a vinyl group, phenyl group, acrylic group or methacrylic group provided on the surface of the particle main body,
The average particle size of the ceramic powder is 0.0005 or more and 0.0100 or less, when the average particle size of the metal powder is 1,
A powder for additive manufacturing, characterized in that a mixing ratio of the ceramic powder to the metal powder is 0.005% by mass or more and 0.100% by mass or less. A powder for additive manufacturing used in an additive manufacturing method,
When the particle size when the cumulative volume based on volume is 10% from the small diameter side is D10, the particle size when 50% is D50 is the average particle size, and the particle size when 90% is D90, the particle size is A metal powder having a diameter D10 of 1.0 μm or more and 4.1 μm or less, an average particle size of 2.3 μm or more and 10.1 μm or less, and a particle size D90 of 4.0 μm or more and 27.1 μm or less;
Ceramic powder with an average particle size of 3.0 nm or more and 15.0 nm or less,
including;
The additive manufacturing method is a binder jetting method,
The average particle size of the ceramic powder is 0.0005 or more and 0.0100 or less, when the average particle size of the metal powder is 1,
A powder for additive manufacturing, characterized in that a mixing ratio of the ceramic powder to the metal powder is 0.005% by mass or more and 0.050% by mass or less. The ceramic powder includes surface-treated ceramic particles,
The ceramic particles subjected to the surface treatment have a particle body and a vinyl group, phenyl group , acrylic group, methacrylic group , or alkyl group provided on the surface of the particle body. Powder for additive manufacturing. The additive manufacturing powder according to any one of claims 1 to 3, wherein the main material of the ceramic powder is silicon oxide. The powder for additive manufacturing according to any one of claims 1 to 4, wherein the constituent material of the metal powder is stainless steel. A step of obtaining a molded body by a binder jetting method using the powder for layered manufacturing according to any one of claims 1 to 5;
firing the molded body to obtain a sintered body;
A method for manufacturing a laminate-molded object, comprising:

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