JP7216362B2 - Three-dimensional modeling method, three-dimensional modeling apparatus and base material used therefor - Google Patents

Description

The present invention relates to a three-dimensional modeling method, a three-dimensional modeling apparatus, and a base material used therefor.

Powder Bed Fusion (PBF) method is known as one of the additive manufacturing techniques for producing an object based on numerical representation of a three-dimensional shape (typically 3D CAD data). ing. In this PBF method, slice data corresponding to a state in which a target modeled object is cut into a plurality of thin layers is prepared. Then, a powder layer called a powder bed is prepared by spreading raw material powder on a flat metal plate called a build platform or base material for forming. The powder bed is irradiated with a laser beam or an electron beam while being scanned according to the slice data, thereby forming a cross-sectional layer in which the powder particles are melted and densified. By successively and integrally manufacturing subsequent cross-sectional layers on this cross-sectional layer, it is possible to manufacture a model having a desired three-dimensional shape.

In the PBF method, at first, resin powder was heated with a carbon dioxide laser to form a model. However, due to the recent increase in beam output, etc., metal powders have come to be used as powders for modeling, and then the use of powder materials made of WC-based cermets has also been attempted (see, for example, Patent Documents 1 to 3). ). Conventionally, the powder particles have been sintered without being melted, so that the shaped article has many pores. However, in the PBF method using a high-power beam such as a fiber laser or an electron beam, it is possible to completely melt the powder particles and form a model, and a model with a low porosity can be obtained (for example, , see Patent Document 1).

U.S. Patent Application Publication No. 2016/0375493 International Publication No. 2015/162206 Japanese Patent Application Laid-Open No. 2016-172904

By the way, unlike the PBF method that uses only metal materials, in the PBF method that uses a powder material containing a ceramic component such as cermet, the modeled object floats from the metal base material for modeling, or the interface with the metal base material is damaged. Problems such as cracks appearing in the modeled object in the vicinity of the modeled object could arise, and the modeling could not be carried out well. The floatation of the modeled object prevents the heat input for modeling from being released to the metal base material at the relevant portion, and may cause heat accumulation and excessive heat supply to the modeled object. As a result, in some cases, the modeled object is distorted, or the modeled object suddenly peels off or cracks from the metal base material, making it impossible to continue modeling.

The present invention has been made in view of this point, and its object is to suppress the lifting and peeling of a modeled object from a modeling substrate when, for example, powder containing a ceramic component is used as the modeling powder. To provide a three-dimensional modeling method capable of Another object of the present invention is to provide a three-dimensional modeling apparatus in which floating and peeling of a modeled object from a modeling substrate is suppressed when a powder containing a ceramic component is used as the modeling powder, and a substrate used therefor. I will provide a.

A thick plate made of relatively hard stainless steel (eg, SUS304, SUS316, etc.) is used as the metal base material for the PBF method so that the base material does not warp due to molding. According to the studies of the present inventors, there is no problem when metal powder is used for molding, but in PBF using a powder material containing a ceramic component (for example, WC) such as cermet, iron ( It was found that the Fe) component reacts with the ceramic component contained in the modeling powder to form a reaction product at the interface between the modeled article and the modeling substrate, which is a unique phenomenon. This interfacial reaction layer is ceramicized and is more brittle than metal. Therefore, when the size of a modeled object made of cermet increases to a certain extent, the difference in thermal expansion characteristics between the metallic substrate and the modeled object accumulates, and the modeled object floats or peels off from the metallic substrate at the interface reaction layer. It turned out that it could crack. In order to suppress such phenomena, it may be effective, for example, to manufacture the modeling base material from the same material as the modeled article. However, a thick plate made of, for example, a WC-based cermet, which is a cemented carbide, is extremely expensive, and it is very difficult in terms of cost to prepare such a material for each molding.

Therefore, the technology disclosed here provides a three-dimensional modeling method. This three-dimensional modeling method comprises: preparing modeling powder containing at least a ceramic component; forming a substrate; preparing a modeling support substrate comprising a reaction-preventing film that prevents reaction with the modeling support substrate; preparing a powder bed by laying the modeling powder in a layer on the modeling support substrate; forming a model on the modeling support substrate by a powder bed fusion (PBF) method of supplying energy rays to the powder bed. According to this three-dimensional modeling method, a modeling substrate having a reaction-preventing film on its surface is used as a modeling support substrate. Thereby, it is possible to suitably suppress the reaction between the ceramic component contained in the modeled article and the modeling base material. Therefore, the molding using the molding powder containing the ceramic component can be performed inexpensively and easily with high molding accuracy.

In a preferred embodiment of the technology disclosed here, the anti-reaction film is a thermal spray coating. It is preferable that the reaction-preventing film is provided as a thermally sprayed coating, because a reaction-preventing film having both adhesion and heat resistance is provided. Moreover, the thermal spray coating is preferably a ceramic thermal spray coating. Ceramic spray coatings are ceramic, but do not react with the substrate for modeling. As a result, the reaction between the ceramic component (for example, WC) contained in the modeled article and the metal substrate can be particularly preferably suppressed.

In a preferred aspect of the technology disclosed herein, the surface roughness of the anti-reaction film is 0.5 μm or more and 5 μm or less. As a result, moderate friction can occur between the modeling powder and the surface of the anti-reaction film. As a result, the powder for modeling can be suitably spread thinly on the modeling support substrate without slipping.

In a preferred embodiment of the technology disclosed herein, the modeling substrate contains stainless steel. Since the modeling support base material is provided with a reaction-preventing film on the surface of the modeling base material, it is not necessary to use a modeling support base material having a cemented carbide composition such as WC/Co. Also, stainless steel has high rigidity and heat resistance, and is preferable as a base material for modeling in the PBF method. This is preferable because the modeling support base material having the above effects can be prepared at low cost.

In a preferred embodiment of the technology disclosed here, a laser is used as the energy beam. This is preferable because the powder for modeling can be melted with a large output and a dense modeled object can be produced.

Another aspect WHEREIN: The technique disclosed here provides a three-dimensional modeling apparatus. This three-dimensional modeling apparatus includes a powder reservoir that stores modeling powder containing at least a ceramic component, and a modeling section that performs modeling by a powder bed fusion bonding method using the modeling powder. The modeling unit includes a modeling support substrate that supports a modeled object, and the modeling support substrate includes a modeling substrate and the modeling powder provided in at least a modelable region of the modeling substrate. and a reaction prevention film that prevents reaction with the modeling substrate. This is preferable because it suppresses the reaction between the modeled object containing the ceramic component and the modeling support base material, and enables stable three-dimensional modeling.

In yet another aspect, the technology disclosed herein provides a modeling support substrate. This modeling support base is for use in three-dimensional modeling of a powder bed fusion bonding method using modeling powder containing at least a ceramic component. The modeling support substrate includes a modeling substrate, and a reaction prevention film provided in at least a modelable region of the modeling substrate and preventing reaction between the modeling powder and the modeling substrate. .
Since a modeled object is directly formed on the modeling support substrate, if the modeled object is a metal material or a cermet material, it may be difficult to separate the modeled object without damaging the modeling support substrate. And the build support substrate can also be a consumable item. Therefore, the technology disclosed herein provides a modeling support base material that does not react with modeling powder containing a ceramic component, even as an independent article.

FIG. 1 is a schematic diagram showing the configuration of a three-dimensional modeling apparatus according to one embodiment. FIG. 2 is a cross-sectional view of a modeling support substrate according to one embodiment. FIGS. 3(a) and 3(b) are low-magnification observation images of the models of Examples 1 and 2. FIG. 4(a) and 4(b) are high-magnification cross-sectional observation images of the vicinity of the interface between the shaped article and the base material of Examples 1 and 2. FIG.

Preferred embodiments of the present invention are described below. Matters other than those specifically mentioned in this specification, which are necessary for carrying out the present invention, are based on the teachings for carrying out the invention described in this specification and the common general knowledge in the relevant field at the time of filing. and can be understood and implemented by those skilled in the art. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios. Further, in this specification, "A to B" indicating a numerical range means "A or more and B or less".

(three-dimensional modeling method)
The three-dimensional modeling method disclosed here includes the following steps S1 to S4.
S1. Preparing a molding powder containing at least a ceramic component S2. Preparing a modeling support substrate comprising a modeling substrate and a reaction prevention film provided in a modelable region of the modeling substrate S3. Preparing a powder bed by spreading the modeling powder in a layer on the modeling support substrate S4. Modeling a modeled object on the modeling support base material by a powder bed fusion bonding method that supplies energy rays to the powder bed.

In addition, although this three-dimensional modeling method is not limited to this, it can be suitably carried out by using, for example, the modeling support base material disclosed herein and a three-dimensional modeling apparatus. FIG. 1 is a schematic diagram showing the configuration of a three-dimensional modeling apparatus 1 according to one embodiment. The three-dimensional modeling apparatus 1 includes at least a powder storage section 10 and a modeling section 20 . The modeling section 20 includes a modeling support base material 26 that supports the modeled object.
Each step of the three-dimensional modeling method will be described below together with the three-dimensional modeling apparatus 1 .

(S1: first step)
In the first step, a molding powder 2 containing at least a ceramic component is prepared. This modeling powder 2 is for use as a modeling raw material in PBF three-dimensional modeling. This modeling powder 2 is stored in the powder storage unit 10 of the three-dimensional modeling apparatus 1 . The powder storage unit 10 includes, for example, a storage tank 12 , an elevating table 14 that constitutes the bottom of the storage tank 12 and is configured to be able to move up and down, and a recoater 16 . A space formed by the storage tank 12 and the upper surface of the lifting table 14 stores the modeling powder 2 .

The ceramic component may be, for example, a ceramic (oxide ceramic) material composed of oxides of various metals, or a ceramic material composed of non-oxides such as carbides, borides, nitrides, and apatites. good. Here, the oxide-based ceramics are not particularly limited, and various kinds of metal oxides can be used. Examples of metal elements constituting such oxide ceramics include metalloid elements such as boron (B), silicon (Si), germanium (Ge), antimony (Sb), bismuth (Bi), magnesium (Mg), Typical elements such as calcium (Ca), strontium (Sr), vanadium (Ba), zinc (Zn), aluminum (Al), gallium (Ga), indium (In), tin (Sn), lead (Pb), scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), silver (Ag), transition metal elements such as gold (Au), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Er), lutetium (Lu), and other lanthanoid elements. Among them, one or more elements selected from Mg, Y, Ti, Zr, Cr, Mn, Fe, Zn, Al, and Er are preferable.

More specifically, oxide-based ceramics include, for example, alumina, zirconia, yttria, chromia, titania, cobaltite, magnesia, silica, calcia, ceria, ferrite, spinel, zircon, nickel oxide, silver oxide, copper oxide, oxide Zinc, gallium oxide, strontium oxide, scandium oxide, samarium oxide, bismuth oxide, lanthanum oxide, lutetium oxide, hafnium oxide, vanadium oxide, niobium oxide, tungsten oxide, manganese oxide, tantalum oxide, terpium oxide, europium oxide, neodymium oxide , tin oxide, antimony oxide, antimony-containing tin oxide, indium oxide, tin-containing indium oxide, zirconium oxide aluminate, zirconium oxide silicate, hafnium oxide aluminate, hafnium silicate oxide, titanium oxide silicate, lanthanum oxide silicate, lanthanum oxide aluminate , yttrium silicate oxide, titanium silicate oxide, and tantalum silicate oxide.

Examples of non-oxide ceramics include carbides such as tungsten carbide (WC), chromium carbide, vanadium carbide, niobium carbide, molybdenum carbide, tantalum carbide, titanium carbide, zirconium carbide, hafnium carbide, silicon carbide, and boron carbide. , tungsten boride (WB), molybdenum boride, chromium boride, hafnium boride, zirconium boride, tantalum boride, borides such as titanium boride, nitrides such as boron nitride, titanium nitride, silicon nitride, aluminum nitride compounds such as forsterite, steatite, cordierite, mullite, barium titanate, lead titanate, lead zirconate titanate, Mn-Zn ferrite, Ni-Zn ferrite, sialon, etc., hydroxyapatite, calcium phosphate, etc. A phosphoric acid compound and the like can be mentioned. Among others, it is preferable to use tungsten carbide (WC), which easily reacts with stainless steel, which is widely used as a material for forming substrates, because the effect of the technology added here appears remarkably.

The above ceramics may be doped or substituted with any element. Moreover, any one of these ceramics may be contained alone, or two or more thereof may be contained in combination. For example, when two or more ceramics are included, some or all of them may form a composite. Examples of such composite ceramics include, specifically, yttria-stabilized zirconia, partially-stabilized zirconia, gadolinium-doped ceria, lanthanum-doped lead zirconate titanate, the above sialon, and the above composite oxide. things, etc. By including such a ceramic in the powder for modeling, it is possible to model a modeled object containing the ceramic.

In addition to the ceramic component, the molding powder preferably contains a binding metal component. The binding metal component is at least one of iron (Fe), cobalt (Co) and nickel (Ni). That is, since such molding powder contains carbide-based ceramics, such as tungsten carbide (WC), and a binding metal component, it can form a cermet in the molding by molding. That is, by using a molding powder containing such components, it is possible to mold a molded object made of cermet.

Here, in the powder for modeling capable of forming a cermet, W, C and B constituting the ceramic phase preferably account for 70% by mass or more of the entire powder for modeling. A cermet containing a W-based ceramic phase in such a proportion is known to be a cemented carbide. If the content of these ceramic phase components is less than 70% by mass, the cermet formed after molding cannot sufficiently obtain the superhardness characteristic of the cermet, which is not preferable. In addition, the content of ceramic phase components is preferably 95% by mass or less, more preferably 90% by mass or less, and particularly preferably 85% by mass or less. In other words, the combined metal component is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 15% by mass or more. If the amount of the binding metal component is too small, the amount of the binding metal that binds the ceramic phases together becomes small, and the cermet tends to be highly brittle, which is not preferable. Each of these components has a powder form. Each component may constitute the powder by itself, or any two or more of the components may form a compound to constitute the powder. The powder may be a powder consisting mainly of aggregates of primary particles, or may be a powder in the form of secondary particles in which the primary particles are combined. The shaping powder is more preferably a powder in the form of secondary particles so that each component maintains its homogeneity during storage and shaping. This allows, for example, leveling and fluidizing the molding powder to prepare a thin layer (powder bed) of the molding powder, and even if the molding powder is repeatedly recycled, the density of each component will increase. This is preferable because gradual separation due to differences or the like can be suppressed.

The average particle size of the powder for modeling is not particularly limited, and can be, for example, a size suitable for the specifications of the powder layered modeling apparatus to be used. For example, the particle size may be suitable for forming a thin layer of the modeling powder by fluidizing the modeling powder during modeling. The upper limit of the average particle size of the powder for modeling can be, for example, more than 100 μm when it is larger, but can be typically 100 μm or less, preferably 75 μm or less, or more. It is preferably 50 μm or less, more preferably 40 μm or less, and for example, 10 μm or less. The molding powder is preferable in that as the average particle diameter becomes smaller, the filling rate of the molding powder in the molding area improves, for example. As a result, it is possible to suitably increase the denseness of the three-dimensional model that is directly modeled. In addition, it is possible to reduce the surface roughness (Ra) of the three-dimensional modeled object and to improve the dimensional accuracy.

Further, the lower limit of the average particle size of the powder for modeling is not particularly limited as long as it does not affect the fluidity and handleability of the powder for modeling. Although it is not limited to this, when it is made smaller, the average particle size can be, for example, 10 μm or less, 5 μm or less, or further 1 μm or less. However, in the case of the molding powder having the form of secondary particles, it is not always necessary to reduce the average secondary particle size. Therefore, for example, in consideration of the handling in forming the molding powder and the fluidity of the molding powder, the lower limit of the average particle diameter can be set to 1 μm or more, and 5 μm or more is appropriate. 10 μm or more is preferable, and for example, 20 μm or more is more preferable. As the average particle size of the molding powder increases, the fluidity of the molding powder can be improved. As a result, the powder for modeling can be well supplied to the modeling apparatus, and the finish (modeling accuracy) of the three-dimensional model to be produced is improved, which is preferable.

In general, fine powder materials having an average particle size of less than 10 μm, for example, are difficult to control the particle shape, and the specific surface area is increased, so the fluidity may be lowered. Therefore, when such a powder material is used for powder additive manufacturing, it tends to be difficult to flatten the powder material when it is supplied. Furthermore, due to its small mass, scattering of such powder materials may occur, making handling difficult. This tendency can be particularly conspicuous because the modeling powder is blown up by the recoil when the laser or electron beam is irradiated in the modeling process described later. On the other hand, when the powder for modeling is composed of secondary particles, the particles can be weighted while maintaining the shape of the primary particles. Further, as described above, even if the first powder and the second powder having different compositions are included, the component concentration in the modeling powder can be kept uniform. This is preferable because both the advantage of using primary particles with a smaller average particle size and the advantage of using secondary particles with a larger average particle size can be combined.

When the molding powder has the form of secondary particles, the primary particles may be bound by a binder, or may be directly bound by sintering or the like without including a binder or the like. Preferably, the molding powder is binderless and has the form of secondary particles. The molding powder is, for example, an aggregate of granulated sintered particles. Here, the granulated sintered particles refer to particulate matter (particles) that are formed by sintering primary particles and behave like one particle. The term "sintered" as used herein refers to a state in which primary particles are directly bonded to each other. Therefore, sintering may be either solid phase sintering or liquid phase sintering. Also, sintering as used herein may include so-called fusion bonding and fusion bonding. Lasers, electron beams, arcs, and the like are widely used as energy sources in powder additive manufacturing, and when they irradiate the modeling powder, high energy is released and impact can occur on the modeling powder. Due to such an impact, the granulated particles bound by the binder may collapse or the primary particles may scatter. In order to avoid the occurrence of such a situation, the granulated particles are preferably configured as so-called granulated sintered particles in which individual primary particles are bonded by sintering. The granulated sintered particles are preferable because even when irradiated with a laser or the like having a higher intensity as an energy source, the powder for modeling is less likely to collapse and scatter. This is preferable because it can lead to a faster build speed (for example, the laser scan speed can be increased or there is no need to reduce the laser scan speed) without impairing the build accuracy and quality of the build.

The granular strength (sintering strength) of the granulated sintered particles that constitute the powder for modeling can be specified to exceed 1 MPa. As a result, it is possible to suitably prevent the granulated sintered particles from collapsing or scattering due to energy for shaping. As a result, the supply of the material powder to the modeling area is stabilized, so that it is possible to form a uniform, high-quality object, which is preferable. As a rough guideline, for example, granulated particles that are granulated and integrated with a binder can be considered to have a granule strength of less than 1 MPa. The granular strength of the granulated sintered particles is preferably 10 MPa or higher, more preferably 50 MPa or higher, and particularly preferably 100 MPa or higher (for example, 200 MPa or higher). However, according to the study of the inventors, if the granule strength is too high, it becomes difficult to sufficiently melt the powder for modeling, which is not preferable. In addition, granulated sintered particles with too strong granular strength are sintered until they have a structure similar to that of single particles that are not granulated, and their properties are similar to spherical particles. put away. From this point of view, the granule strength is set to less than 10000 MPa. The granule strength is preferably 5000 MPa or less, more preferably 2500 MPa or less, particularly preferably 1000 MPa or less (eg 800 MPa or less).

In the present specification, the "granule strength" of the granulated sintered particles constituting the powder for modeling can be the breaking strength of the particles measured using an electromagnetic force loading type compression tester. Specifically, one granulated sintered particle is fixed between the pressurizing indenter and the pressurizing plate, and a compressive load force is applied between the pressurizing indenter and the pressurizing plate at a constant increasing rate by electromagnetic force. To go. Compression is performed by a constant load speed compression method, and the amount of deformation of the measurement sample at that time is measured. A strength value (breaking strength) can be calculated by processing the measured deformation characteristics of the sample with a dedicated program. In the present specification, the arithmetic of the breaking strength measured using a microcompression tester (manufactured by Shimadzu Corporation, MCT-500) for arbitrary 10 or more granulated sintered particles constituting the molding powder The average value is taken as the granule strength. For each granulated sintered particle, when the critical load obtained in the compression test is L [N] and the average particle diameter is d [mm], the breaking strength σ [MPa] of the granulated sintered particle is , the following formula: σ=2.8×L/π/d ² ;

Such a molding powder has gaps between a plurality of particles (typically primary particles) that make up the powder. Gaps are formed between the individual primary particles, and the primary particles are three-dimensionally bonded to each other. As a result, the powder for modeling has the advantage of easily receiving energy from an energy source (heat source) and being easily melted. As a result, the gaps between the secondary particles are easily eliminated, and it is possible to obtain a highly dense and highly rigid molded article, which is similar to a sintered body (bulk body) produced using a mold, for example.

On the other hand, in the powder for modeling disclosed herein, the average particle size of the primary particles that make up the secondary particles is, for example, preferably 20 μm or less (less than 20 μm), and is 10 μm or less (less than 10 μm). is more preferable, and can be, for example, 10 μm or less. By making the average particle size of the primary particles finer in this way, it becomes possible to produce a three-dimensional structure that is even more dense and fine. In addition, the average particle diameter of the raw material powder used for producing the molding powder in the form of secondary particles can be, for example, 1 nm or more, more preferably 200 nm or more, and for example, 500 nm or more. be able to. The average particle size of the raw material powder is more preferably 10 μm or less (less than 10 μm), and can be, for example, 10 μm or less. By making the average particle size of the primary particles finer in this way, it becomes possible to produce a three-dimensional structure that is even more dense and fine.

(S2: second step)
In the second step, a modeling support base material 26 is prepared. FIG. 2 is a cross-sectional view for explaining the configuration of the modeling support base material 26. As shown in FIG. The modeling support base material 26 includes a modeling base material 26B and a reaction prevention film 26A provided at least in a modelable region of the three-dimensional modeling apparatus 1 on the surface of the modeling base material 26B. In FIG. 2, the anti-reaction film 26A is provided over one entire surface of the modeling base material 26B. It is preferable that the reaction-preventing film 26A covers the entire surface of one surface of the modeling base material 26B because the adhesion of the reaction-preventing film 26A is enhanced. However, the anti-reaction film 26A may be provided at least in the modelable region without covering the entire surface of the modeling substrate 26B. The modelable region is the upper surface of the model support base material 26, and refers to a region that can be irradiated with energy rays from a laser generator 28, which will be described later.

The modeling base material 26B is preferably made of various metal materials from the viewpoint of performing modeling by the PBF method. At the initial stage of modeling by the PBF method, a high-power beam is applied to the modeling powder 2 at a position close to the modeling support base material 26, so the modeling base material 26B has heat resistance and heat resistance strength. It is preferable that the material is excellent in As such a material, it is preferable to use austenitic stainless steel represented by SUS304, SUS316, SUS316L, etc., which has been widely used as a base material for modeling. The dimensions of the modeling base material 26</b>B may be appropriately set according to the dimensions of the modeling area of the three-dimensional modeling apparatus 1 . The base material for modeling 26B is required not to deform even when a modeled object formed on this base material accumulates thermal stress inside due to, for example, uneven heat accumulation. Therefore, the thickness of the modeling substrate 26B can be, for example, 5 mm or more, preferably 10 mm or more, more preferably 12 mm or more, and may be 15 mm or more, for example. The upper limit of the thickness of the modeling substrate 26B is not particularly set, and may be, for example, about 5 cm or less.

The reaction prevention film 26A has a function of preventing reaction between the modeling powder 2 and the modeling substrate 26B. According to studies by the present inventors, it is considered that the reaction between the modeling powder 2 and the modeling base material 26B is caused by migration of components of the modeling powder 2 to the modeling base material 26B side. Therefore, the anti-reaction film 26A can be preferably made of a material capable of suppressing the migration of the components of the modeling powder 2 . Such a material includes, for example, a compound that blocks movement of the elements constituting the molding powder 2, or a compound that easily incorporates the element into its crystal structure. Since such metallic materials and ceramic materials overlap with the materials described in the column of powders for molding, repeated descriptions thereof are omitted. Among them, the reaction prevention film 26A is preferably, for example, a metal containing at least one metal element constituting the model and/or an oxide thereof, and a metal containing all the metal elements constituting the model and/or an oxide thereof. More preferably, it is made of a material having the same composition as that of the modeled article. As a result, migration can be prevented, and even if the modeling powder reacts with the anti-reaction film at the initial stage of modeling, deterioration can be avoided.

Also, the method of forming the reaction prevention film 26A is not particularly limited. For example, plating, thermal spraying, paste coating, printing, sol-gel, spin coating, chemical vapor deposition, physical vapor deposition, or the like may be used. In particular, the reaction prevention film 26A is preferably a thermal spray coating formed on the surface of the modeling substrate 26B by thermal spraying. In the thermal spraying method, a powdery thermal spraying material made of various resins, metals, ceramics, cermets, etc. is softened or melted by combustion or electric energy and sprayed onto the surface of the base material. As a result, a thermal spray coating made of the thermal spray material is formed on the surface of the substrate. In particular, it is particularly preferable to employ a high-speed flame spraying method or a low-pressure plasma spraying method as the thermal spraying method because it is possible to form a reaction-preventing film with good adhesion to the modeling substrate 26B.

Moreover, when the anti-reaction film 26A is a thermal spray coating, the thermal spray coating may contain pores moderately. Such a configuration is preferable because the difference in thermal stress generated between the modeling substrate 26B and the modeled object can be moderated. From this point of view, the reaction prevention film 26A may have a porosity of 0.5% to 15%, preferably 1% to 10%, for example 1% to 5%. This is preferable because the thermal stress relaxation effect can be exhibited more effectively while providing an appropriate strength.

The anti-reaction film 26A is preferably formed after roughening the surface of the modeling base material 26B in order to increase adhesion and adhesion strength with the modeling base material 26B. As a result, the anti-reaction film 26A and the modeling base material 26B are meshed with each other mechanically, which is preferable for achieving higher adhesion strength. As the surface roughening treatment, for example, blasting treatment using abrasive grains of about #10 to #50 (for example, alumina grid) is shown as a preferred example. By this blasting, the surface of the modeling base material 26B can be roughened to a surface roughness Ra of about 3 to 7 μm. This is preferable because the adhesion and adhesion strength between the modeling substrate 26B and the anti-reaction film 26A are enhanced, and as a result, the adhesion and adhesion strength between the modeling support substrate 26 and the modeled object also increase.

The thickness (average thickness) of the anti-reaction film 26A is not strictly limited because it varies depending on the composition, size, shape, etc. of the object to be shaped. From the viewpoint of reliably preventing the reaction between the body and the modeling substrate 26B, the thickness is more preferably 300 μm or more. Although the upper limit of the thickness of the anti-reaction film 26A is not particularly limited, it is recommended that the thickness be approximately 500 μm or less, for example.

Further, the anti-reaction film 26A preferably has a surface roughness Ra of about 2 to 6 μm on the side not bonded to the modeling substrate 26B. This is desirable because the modeling powder 2 can be easily spread thinly on the surface of the modeling support base material 26 at the initial stage of modeling.

The modeling support base material 26 is provided in the modeling section 20 of the three-dimensional modeling apparatus 1 as shown in FIG. The modeling section 20 is provided on the side of the powder storage section 10 . The modeling unit 20 has a function of modeling a modeled object by the PBF method. The modeling unit 20 includes a modeling tank 22, a lifting table 24 that constitutes the bottom of the modeling tank 22 and is configured to be able to move up and down, a modeling support base material 26, and a laser generator 28 as a heat source. A space formed by the modeling tank 22 and the upper surface of the elevating table 24 serves as a modeling area. The modeling support base material 26 is detachably fixed to the upper surface of the elevating table 24 . For example, the modeling support base material 26 is fixed to the upper surface of the elevation table 24 before modeling, and is removed from the elevation table 24 together with the modeled object after modeling. The modeling support base material 26 serves, for example, as a modeling table on which a modeled object is placed and supported.

(S3: third step)
In the third step, a powder bed is prepared by spreading the modeling powder 2 in a layer on the modeling support base material 26 . In the three-dimensional modeling apparatus 1, the upper ends of the storage tank 12 and the modeling tank 22 are substantially flush. The recoater 16 is arranged so as to span the storage tank 12 and the modeling tank 22 . Since the lift table 14 is lowered as shown in FIG. 1, the storage amount of the molding powder 2 that can be stored in the powder storage section 10 is increased. A predetermined amount of the molding powder 2 can be extruded from the storage tank 12 by raising the lifting table 14 by a predetermined thickness Δt1 while the storage tank 12 contains the molding powder 2 . In the modeling section 20, the lifting table 24 is lowered from the upper end by a predetermined thickness Δt2, so that the molding powder 2 can be accommodated with a predetermined thickness Δt2.

In the three-dimensional modeling apparatus 1, the molding powder 2 is extruded from the storage tank 12, and the recoater 16 passes over the storage tank 12 and the modeling tank 22 from the end of the storage tank 12. 22 to the opposite end. As a result, the modeling powder 2 extruded from the storage tank 12 can be moved to the modeling tank 22 by the recoater 16 and spread over the modeling tank 22 . Further, by scanning the surface of the modeling powder 2 supplied to the modeling tank 22 with the recoater 16, the upper surface of the modeling powder 2 is flattened to form a uniform thin layer of the modeling powder 2. can be done. Thereby, a layer (powder bed) of the modeling powder 2 having a predetermined thickness Δt2 can be prepared. Further, the upper surface of the molding powder 2 leveled by the recoater 16 becomes the molding surface.

(S4: fourth step)
In the fourth step, a modeled object is modeled on the modeling support base material 26 by a powder bed fusion bonding method in which energy rays are supplied to the powder bed. The three-dimensional modeling apparatus 1 of this embodiment includes a laser generator 28, which generates a laser as an energy beam to irradiate the powder bed. The laser generator 28 oscillates laser light in scanning lines based on, for example, layered manufacturing data. Laminate manufacturing data is three-dimensional data of cross-sectional images in each cross-sectional layer when the object to be manufactured is sliced into a plurality of layers. Laminated modeling data can be prepared by, for example, creating a three-dimensional shape of an object to be modeled using 3D CAD software, 3D CG software, etc., and converting it into an STL (Standard Triangulated Language) format. The preparation of the additive manufacturing data may be the same as in the prior art, and since it does not characterize the technology disclosed here, further detailed description is omitted. This layered modeling data is stored in a storage unit (not shown) of the three-dimensional modeling apparatus 1 . As a result, the modeling powder 2 is melted and then solidified. As a result, the modeling powder 2 is combined into a cross-sectional shape corresponding to the layered modeling data. As a result, for example, a first cross-sectional layer can be formed.

The three-dimensional fabrication method of the PBF method includes so-called laser sintering method, selective laser sintering (SLS) method, electron beam sintering method, and the like. Note that a laser is preferably used as the energy source from the viewpoint of being able to supply energy with higher density. The type of laser is not particularly limited, and may be, for example, a solid laser (YAG, glass, ruby, etc.), a liquid laser, a gas (carbon dioxide gas, etc.) laser, a semiconductor laser, a free electron laser, a chemical laser, a fiber laser, or the like. . Since this PBF type three-dimensional modeling method is also the same as the conventional one, further detailed description will be omitted.

In the fourth step, the elevating table 14 is raised by a predetermined thickness Δt1 to extrude the modeling powder 2 again, and the elevating table 24 is lowered by a predetermined thickness Δt2 to create a storage space for the modeling powder 2 in the modeling tank 22. set up. Then, with the molding powder 2 pushed out from the storage tank 12 , the recoater 16 is moved from the end of the storage tank 12 to the opposite side of the modeling tank 22 so as to pass over the storage tank 12 and the modeling tank 22 . move to the end. As a result, the extruded modeling powder 2 can be newly supplied to the modeling tank 22 . Further, the powder bed for the second layer is formed by leveling the modeling powder 2 with the recoater 16 .

Then, the second powder bed is irradiated with an energy beam such as a laser or an electron beam based on the prepared layered manufacturing data. At this time, the powder bed of the second layer is melted and solidified while being integrated with the cross-sectional layer of the first layer, which is the lower layer. As a result, cross-sectional layers up to the second layer are formed. In this way, a powder bed of modeling powder is again prepared on the shaped cross-sectional layer, and the next cross-sectional layer is integrally formed. By repeating this process, it is possible to manufacture a model having a desired three-dimensional shape.

When the modeling of the modeled article is completed, the modeled article is typically removed from the lifting table 24 in a state integrated with the modeling support base material 26 . After that, the modeled object can be obtained by separating the modeled object from the modeling support base material 26 in the vicinity of the sea surface by electric discharge machining or the like.

EXAMPLES Examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples below.

A SUS430 plate having a thickness of 12 mm was used as a substrate for modeling, and a reaction-preventing film was formed thereon. First, using alumina grid #80, after roughening the entire surface of one side of a SUS430 plate (thickness 15 mm) by blasting, high-speed flame spraying is performed on the blasted surface to form a 300 μm thick thermal spray coating (reaction prevention film). made. The surface roughness Ra of the plate by blasting was about 5 μm. As a thermal spraying apparatus, a high-speed flame spraying machine (PRAXAIR/TAFA JP-5000) was used. The thermal spraying powder was composed of cermet (WC/30% Co) containing 70% by weight of tungsten carbide and 30% by weight of cobalt, and had an average particle size of 28 μm (particle size distribution width −45+15 μm). Thermal spraying conditions are oxygen flow rate: 1900 scfh (893 l/min), kerosene flow rate: 5.1 gph (0.32 l/min), spraying distance: 380 mm, barrel: 8 inches (approximately 200 mm), thermal spraying powder feed rate: 75 g/min. min. As a result, the surface roughness Ra of the thermal spray coating as formed on the plate surface was about 5 μm.

Using the above base material for modeling, a metal sintering three-dimensional modeling printer ProX200 manufactured by 3D Systems was used to model a plate-like modeled object with dimensions of 2 cm×5 cm. Granular powder (W1152) containing tungsten carbide with a particle size of −20+5 μm (sieve opening of 20 μm passed, 5 μm not passed) was used as the molding powder. The powder composition is WC/30% Co. The molding conditions were laser output: 255 W, scanning speed: 300 mm/s, pitch width: 0.1 mm, lamination thickness: 0.03 mm. The modeled article obtained in this manner was used as the modeled article of Example 1. As a control, a modeled object of Example 2 was obtained by using the substrate for modeling (SUS430 plate) without the anti-reaction film prepared above and performing modeling under the same conditions.

3(a) and 3(b) show low-magnification observation images of the molded articles of Examples 1 and 2, respectively. As shown in FIG. 3(b), when modeling is performed using the modeling base material of Example 2 which is not provided with a reaction-preventing film, the substrate for modeling is attached to the longitudinal end of the modeled article around the 50th layer of the modeled article. A float was seen. After that, when I continued modeling on the modeled object that was distorted by the float, the modeled object suddenly separated from the modeling substrate around the 100th layer, and it became impossible to continue modeling after that. rice field. On the other hand, by using the modeling substrate of Example 1 provided with the anti-reaction film, the problems of floating and peeling of the modeled object do not occur, and as shown in FIG. was able to complete

Therefore, cross-sections of the molded objects of Examples 1 and 2 were performed, and the cut surfaces near the interface between the molding substrate and the molded object were observed at a high magnification, and the observed images are shown in FIGS. rice field. As shown in FIG. 4(b), when modeling is performed using the modeling substrate without the anti-reaction film of Example 2, a reaction occurs at the interface between the modeled object and the modeling substrate, forming a reaction product. It was confirmed that In the molding of Example 2, it is considered that the fragility of this reaction product caused the interface to be destroyed at the position of the reaction product due to the thermal stress generated during the molding, causing the molded article to float or peel off. On the other hand, as shown in FIG. 4(a), when the modeling substrate provided with the reaction-preventing film of Example 1 is used for modeling, the reaction at the boundary between the modeled object and the modeling substrate is suppressed. It was confirmed that Therefore, in the modeling of Example 1, it was found that a complex-shaped object can be produced without floating or peeling of the object.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the above-described embodiment, the powder storage unit 10 is provided on the side of the modeling unit 20 and pushes out the molding powder 2 from the storage tank 12 by raising the elevating table 14 to supply it. However, the configuration of the powder reservoir 10 is not limited to this. The powder storage unit 10 may be configured, for example, to be provided above the modeling unit 20 and to supply the modeling powder 2 to the modeling tank 22 by dropping the modeling powder 2 .

1 Three-dimensional modeling apparatus 10 Powder reservoir 20 Modeling unit 26 Modeling support base material 26A Reaction prevention film 26B Modeling base material

Claims (7)

preparing a molding powder containing at least a ceramic component;
A modeling support base comprising: a modeling substrate containing stainless steel; and a reaction prevention film provided on at least a modelable region of the modeling substrate and preventing a reaction between the modeling powder and the modeling substrate. prepare materials,
preparing a powder bed by laying the modeling powder in a layer on the anti-reaction film ;
A three-dimensional modeling method, comprising modeling a modeled object on the modeling support base material by a powder bed fusion bonding method that supplies energy rays to the powder bed. The three-dimensional fabrication method according to claim 1, wherein the anti-reaction film is a thermal spray coating. The three-dimensional fabrication method according to claim 2, wherein the thermal spray coating is a ceramic thermal spray coating. The three-dimensional fabrication method according to any one of claims 1 to 3, wherein the reaction prevention film has a surface roughness Ra of 2 µm or more and 6 µm or less. The three-dimensional modeling method according to any one of claims 1 to 4 , wherein a laser is used as the energy beam. a powder reservoir for storing modeling powder containing at least a ceramic component;
a modeling unit that performs modeling by a powder bed fusion method using the modeling powder;
The modeling unit includes a modeling support base that supports the modeled object,
The modeling support substrate includes a modeling substrate containing stainless steel, and a reaction prevention film provided in at least a modelable region of the modeling substrate to prevent reaction between the modeling powder and the modeling substrate. and a three-dimensional modeling apparatus. A modeling support substrate used for three-dimensional modeling by a powder bed fusion bonding method using modeling powder containing at least a ceramic component,
A modeling support comprising: a modeling substrate containing stainless steel; and a reaction prevention film provided in at least a modelable region of the modeling substrate and preventing a reaction between the modeling powder and the modeling substrate. Base material.

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