WO2018221563A1 - Shaping method and shaping device - Google Patents

Abstract

This shaping method is characterized by comprising a step for using a first power to form a powder layer, a step for placing a second powder having an average particle size smaller than that of the first powder on a region constituting a portion of the powder layer, and a first heating step for heating the powder layer on which the second powder is placed, wherein the average particle size of the second powder is 1-500 nm inclusive, and the heating in the first heating step occurs at a temperature at which the particles contained in the second powder are sintered or melted.

Description

Modeling method and modeling apparatus

The present invention relates to a technique for modeling a three-dimensional object using a particulate material.

As a method of modeling a three-dimensional object, a layered modeling method in which modeling materials are stacked in accordance with slice data of a three-dimensional object model that is a modeling object has attracted attention. Conventionally, modeling using a resin material has been the mainstream, but recently, an apparatus that performs modeling using a modeling material other than a resin such as metal or ceramics has been increasing.

Patent Document 1 discloses a method of obtaining a shaped object by repeating a process of forming a thin layer of a powder material on a substrate and then locally heating at a high temperature with a laser to sinter the powder material. . In the method of Patent Document 1, when a structure is formed on a region where the powder material is not sintered (hereinafter referred to as “non-modeling region”), such as a structure with an overhang structure or a movable part, the non-modeling region The powder material present on top of must be sintered. Since warpage may occur due to local heat shrinkage at that time, depending on the shape of the structure, it is necessary to add a support body (also referred to as a support structure) that suppresses the warp. Since the support body is an essentially unnecessary structure, depending on the shape of the three-dimensional object model, it may be necessary to remove it after modeling.Thus, the three-dimensional object model having a shape or structure that makes it difficult to remove the support body can be modeled. Have difficulty. In particular, since it is necessary to use a metal working machine when removing a support body from a metal shaped article, a fine structure that is physically difficult to remove by the metal working machine cannot be formed. Further, since ceramics are easily damaged by a load, it has been difficult to selectively remove a support body from a ceramic model.

Moreover, after producing the shape of a molded article using the mixed material of particles, such as metal or ceramics, and a resin binder, the method of obtaining the molded article of a metal or ceramics by removing (degreasing) resin and sintering. Are known. Patent Document 2 discloses a method of producing a composite shaped article of resin and metal particles by removing a region that has not been solidified after repeating the step of applying and solidifying a liquid binder to the metal particle-containing layer. ing. The resulting composite model is degreased and sintered by heat treatment to obtain a metal model.

In the method of Patent Document 2, when a shape having an overhang structure, a structure having a movable part, or the like is produced, a powder not coated with a binder (non-solidified powder) is formed instead of a support body. . However, since the powder in place of the support body must be removed before degreasing and sintering, the shape cannot be maintained after degreasing and may be deformed or broken. In addition, when modeling shapes with different thicknesses are mixed in the modeled object, impurities in the modeled object increase if the degreasing in the thick part is insufficient, and the thin part deforms if the degreasing of the thick part is sufficient, It may be damaged. Therefore, in the modeling method of Patent Document 2, there are limitations on the shape and size that can be modeled. However, if heat treatment is performed without removing the powder instead of the support body in order to maintain the shape, the metal particles in the non-modeling area may merge with the metal particles in the modeling area, and the desired shape may not be obtained. There is.

In addition, the shape of the composite molded article of resin and metal is maintained by the resin component, but if the resin component is large, deformation and breakage during degreasing and voids in the formed molded article may be caused. On the other hand, if the resin component is small, the strength of the resin-metal composite model is weakened, and the model may be damaged when removing the particles in the non-modeling region.

Japanese Patent Laying-Open No. 2015-38237 Japanese Patent Laying-Open No. 2015-205485

As described above, there is a limit to the shape that can be shaped by the conventional modeling method. In particular, in a method using a modeling material such as a metal or ceramics, it is difficult to say that a desired physical property or shape can be modeled.
Then, this invention aims at providing the modeling technique with few restrictions of the shape which can be modeled.

The first aspect of the present invention is:
Forming a powder layer using the first powder;
Disposing a second powder having an average particle size smaller than that of the first powder in a partial region of the powder layer;
A first heating step for heating the powder layer in which the second powder is disposed;
Including
The average particle size of the second powder is 1 nm or more and 500 nm or less,
The first heating step provides a forming method characterized in that heating is performed at a temperature at which particles contained in the second powder are sintered or melted.

The second aspect of the present invention is:
Powder layer forming means for forming a powder layer using the first powder;
Arranging means for disposing a second powder having an average particle diameter smaller than that of the first powder in a partial region of the powder layer;
Heating means for heating the powder layer so that particles contained in the second powder are sintered or melted;
The modeling apparatus characterized by having is provided.

According to the present invention, it is possible to provide a modeling technique with few restrictions on shapes that can be modeled.

1A to 1H are diagrams schematically showing a modeling method according to an embodiment of the present invention. 2A to 2G are views schematically showing a modeling method according to the embodiment of the present invention. FIG. 3 is a diagram schematically illustrating a modeling method according to the embodiment of the present invention. FIG. 4 is a diagram illustrating a flow of the modeling method according to the first embodiment. FIG. 5 is a diagram illustrating a flow of the modeling method according to the second embodiment. FIG. 6 is a diagram illustrating a flow of the modeling method according to the third embodiment. FIG. 7 is a diagram schematically illustrating a modeling apparatus according to the eighth embodiment. FIG. 8 is a diagram schematically illustrating a modeling apparatus according to the ninth embodiment. FIG. 9 is a diagram schematically illustrating a modeling apparatus according to the eleventh embodiment. FIG. 10 is a diagram schematically illustrating a modeling apparatus according to the twelfth embodiment. FIG. 11 is a diagram schematically illustrating a modeling apparatus according to the fourteenth embodiment. FIG. 12 is a diagram schematically illustrating a modeling apparatus according to the fifteenth embodiment.

The present invention relates to a modeling method for producing a three-dimensional model using a particulate material. The method of the present invention can be preferably used in a modeling process in a modeling apparatus called an additive manufacturing (AM) system, a three-dimensional printer, a rapid prototyping system, or the like.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments and examples of the present invention. In each drawing, the same code | symbol is provided to the location which shows the same member or a corresponding member. In particular, a well-known technique or a well-known technique in the technical field can be applied to configurations and processes not shown or described. In addition, overlapping description may be omitted.

(Modeling method)
The modeling method according to the embodiment of the present invention generally includes the following (Step 1) to (Step 4).
(Step 1) Step of forming a powder layer using the first particles (Step 2) Step of applying second particles to the modeling region in the powder layer (Step 3) Sintering the second particles The process of fixing the first particles in the modeling area (Process 4) The process of removing the first particles outside the modeling area

By performing the above (Step 1) to (Step 4), a sheet-like (or plate-like) shaped article having a thickness corresponding to one powder layer can be formed. Furthermore, by repeating the above (Step 1) to (Step 2) and laminating a large number of powder layers, a three-dimensional shaped object can be formed.

(Description of each process)
Hereinafter, each step of the modeling method will be described with reference to FIGS. 1A to 1H, FIGS. 2A to 2G, and FIG. 1A to 1H and FIGS. 2A to 2G schematically show the flow of the modeling method of this embodiment. 1A to 1H are examples of sequences in which (Step 4) is performed after repeating (Step 1) to (Step 3) a plurality of times, and FIGS. 2A to 2G are alternately (Step 1) and (Step 2). It is an example of the sequence which performs (process 3) and (process 4) after repeating several times. FIG. 3 is an enlarged view schematically showing the structure of the powder layer.

In addition, before starting modeling, it is assumed that slice data for forming each layer is generated from the three-dimensional shape data of the modeling target by a modeling apparatus or an external apparatus (for example, a personal computer). As the three-dimensional shape data, data created by a three-dimensional CAD, a three-dimensional modeler, a three-dimensional scanner, or the like can be used. For example, an STL file can be preferably used. The slice data is data obtained by slicing the three-dimensional shape of the modeling object at a predetermined interval (thickness), and is data including information such as a cross-sectional shape, a layer thickness, and a material arrangement. Since the thickness of the layer affects the modeling accuracy, the thickness of the layer may be determined according to the required modeling accuracy and the particle size of the particles used for modeling.

(Step 1) Step of forming a powder layer using the first powder In this step, the powder layer 11 is formed using the first powder including the first particles 1 based on the slice data of the modeling object. (FIGS. 1A and 2A). In the present specification, an aggregate of a plurality of particles is referred to as a “powder”, a powder obtained by leveling a powder to a predetermined thickness is referred to as a “powder layer”, and a laminate of a plurality of powder layers is referred to as a “laminate”. Call it. In the stage of this process, the individual particles constituting the powder layer 11 are not fixed, but the form of the powder layer 11 is maintained by the frictional force acting between the particles.

As the first particles 1 constituting the first powder forming the powder layer 11, for example, resin particles, metal particles, ceramic particles, and the like can be used. As described above, there is a limit to the shapes that can be formed with metal or ceramics, because post-processing (such as removal of a support body) is difficult with conventional modeling methods. On the other hand, the method of the present embodiment can easily form a complex shape or a fine shape even with a metal or ceramic as described later. Therefore, modeling using metal particles or ceramic particles as the first particles is one of the objects to which the modeling method of this embodiment can be preferably applied.

Examples of metals that can be used as the first particles 1 include copper, tin, lead, gold, silver, platinum, palladium, iridium, titanium, tantalum, and iron.
Further, a metal alloy such as a stainless alloy, a titanium alloy, a cobalt alloy, an aluminum alloy, a magnesium alloy, an iron alloy, a nickel alloy, a chromium alloy, a silicon alloy, or a zirconium alloy may be used as the first particles 1.
Further, a material obtained by adding a nonmetallic element such as carbon to a metal such as carbon steel may be used as the first particle 1.
As the first particles, oxide ceramics may be used, or non-oxide ceramics may be used. Examples of oxide ceramics include metal oxides such as silica, alumina, zirconia, titania, magnesia, cerium oxide, zinc oxide, tin oxide, uranium oxide, barium titanate, barium hexaferrite, and mullite. Non-oxide ceramics include silicon nitride, titanium nitride, aluminum nitride, silicon carbide, titanium carbide, tungsten carbide, boron carbide, titanium boride, zirconium boride, lanthanum boride, molybdenum silicide, iron silicide, barium silicide, etc. Can be mentioned. The first particles may be composite particles of a plurality of types of metals or composite particles of a plurality of types of ceramics.

The first powder may contain substances other than the first particles 1. For example, for the purpose of facilitating the formation of the powder layer 11, maintaining the form of the powder layer 11, or favorably controlling the diffusion of the liquid applied in (Step 2) described later, the first An additive may be added to the powder. Thereby, the modeling can be facilitated and the modeling accuracy can be improved. Further, a plurality of types of first particles 1 made of different materials may be mixed in the first powder.

The average particle size of the first powder is preferably set to a size that does not cause aggregation in order to form the powder layer 11 satisfactorily. In addition, the average particle size of the first particles 1 is a dimension suitable for the diffusion of the liquid applied in (Step 2), the particle fixation in the heat treatment of (Step 3), and the strength and function requirements of the modeled object. It is preferable to do. Specifically, the volume-based average particle diameter of the first particles 1 may be selected from a range of 1 μm or more and 500 μm or less, and preferably 1 μm or more and 100 μm or less. When the average particle diameter is 1 μm or more, the aggregation of particles during the formation of the powder layer is suppressed, and the layer formation with few defects tends to be facilitated.

The measurement of the average particle diameter can be performed using a laser diffraction / scattering particle size distribution measuring apparatus LA-950 (manufactured by HORIBA). The attached dedicated software is used for setting the measurement conditions and analyzing the measurement data. As a specific measurement method, first, a batch type cell containing a measurement solvent is set in a laser diffraction / scattering type particle size distribution measuring apparatus LA-950 (manufactured by HORIBA), and the optical axis and background are adjusted. I do. Here, it is necessary to select a solvent that does not dissolve the particles to be measured. Moreover, you may add a dispersing agent in a solvent suitably as needed for the dispersion | distribution improvement of the particle | grains to measure. The powder to be measured is added to the batch cell until the transmittance of the tungsten lamp reaches 95% to 90%, the particle size distribution is measured, and the volume-based average particle size is calculated from the obtained measurement results. be able to.

The first powder may contain a plurality of groups of first particles 1 having different average particle diameters (of course, the average particle diameter of each group is preferably set within the above-described numerical range. ). When the first powder contains a plurality of groups of particles having different average particle diameters, when the particle size distribution of the first powder is measured, a peak indicating a high abundance ratio appears in the vicinity of the average particle diameter of each group .
For example, when the powder layer 11 is formed by mixing the first group of particles having a relatively large average particle diameter and the second group of particles having a relatively small average particle diameter, the first group of particles is formed. The second group of particles can enter the gaps between the gaps, and voids in the powder layer 11 can be reduced. At this time, it is preferable that the average particle diameter of the second group of particles is larger than the average particle diameter of the second particles described later and 0.41 times or less of the average particle diameter of the first group of particles. When the ratio of the average particle size of the first group of particles to the second group of particles is set in this way, the second group of particles is formed in the particle gap (octahedral site) when the first group of particles forms a close-packed structure. Since the particles can be arranged, the space filling rate of the powder layer 11 can be increased as much as possible. Thereby, as a result, a molded article with a small porosity can be produced. The first group of particles and the second group of particles are preferably particles of the same material, but may be particles of different materials.

The first particles 1 preferably have an average circularity of 0.94 or more, and more preferably 0.96 or more. If the average circularity of the first particles 1 is 0.94 or more, the particles have a structure close to a sphere, and the number of points where the particles are in point contact can be reduced. As a result, the fluidity of the first powder containing the first particles 1 is improved, and when the powder layer 11 is formed, the first particles 1 are likely to be closely packed, so that the powder layer 11 with fewer voids is formed. It becomes easy to do.

The circularity of the particles can be measured as follows, and the average circularity can be obtained by averaging the circularities obtained by measuring 10 or more arbitrary particles.

Circularity = (perimeter of a circle having the same area as the projected area of the particle) / (perimeter of the projected image of the particle)

Here, the “particle projected image” can be obtained by binarizing the particle image. The “particle projected area” is the area of the projected image of the particle, and the “peripheral length of the projected image of the particle” is the length of the outline of the projected image of the particle.

The circularity is an index indicating the complexity of the shape of the particle, and indicates 1.00 when the particle is a perfect sphere, and the circularity becomes smaller as the projected image of the particle deviates from the circle. The circularity of the particles can be measured using image processing of an observation image such as an electron microscope and a flow type particle image measuring device (for example, FPIA-3000 type manufactured by Toa Medical Electronics Co., Ltd.).

For example, as disclosed in Japanese Patent Application Laid-Open No. 8-281807, the powder layer 11 is formed by a container having an upper opening, a support body that can be raised and lowered set inside the container, and a material supply provided with a wiper. It can be formed using a device. Specifically, the upper surface of the support is adjusted to a position that is lower than the upper edge of the container by a thickness, and the material is supplied onto the flat plate by the material supply device and then flattened by the wiper. The powder layer 11 of the layer can be formed. Alternatively, a powder layer having a desired thickness can be obtained by supplying the first powder onto a flat surface (the surface of the model or the object being fabricated) and leveling the surface of the powder with a layer thickness regulating means (for example, a blade). 11 may be formed. Further, the powder layer 11 may be pressed by a pressing means (for example, a pressure roller, a pressure plate, etc.). By increasing the number of contact points between the particles by pressurization, defects in the modeled object tend not to be formed. In addition, since the first particles 1 in the powder layer are densely present, the first particles 1 move during the subsequent steps (step 2) and (step 3) (the shape of the powder layer 11 is lost). ) Is suppressed, and a shaped object with high shape accuracy can be produced.

The modeling device has multiple types of first powders with different compositions (that is, it has multiple powder supply units that can store different types of first powders), and the first powder to be used can be switched. It may be. For example, when a plurality of powder layers 11 are laminated, the composition of the powder may be changed for each layer.

(Step 2) Step of placing the second powder in the modeling region of the powder layer In this step, based on the slice data of the modeling object, the liquid application device applies the modeling powder S to the modeling region S of the powder layer 11. A liquid 12 containing the second particles 2 and containing a second powder having an average particle diameter of 1 nm or more and 500 nm or less (also referred to as “particle dispersion 12”) is applied (FIGS. 1B and 2B). Here, the “modeling region S” refers to a region corresponding to the cross section of the modeling target (that is, a portion of the powder layer 11 that should be solidified and taken out as a modeled product). An area outside the modeling area S (that is, a part where the powder is to be finally removed) is referred to as a “non-modeling area N”.

The second powder is a powder that can be sintered and melted at least at a lower temperature and / or shorter time than the first powder. In other words, when the mixed powder of the first powder and the second powder is heated, at least some of the first particles 1 constituting the first powder are not sintered (and naturally melted), The heating conditions (temperature, time, etc.) in which the second particles constituting the second powder are sintered or melted can be set. Here, “sintering” refers to a treatment in which the particles are fixed (bonded) by heating the powder at a temperature below the melting point in a state where the particles are in contact with each other. In addition, “not sintered” means that the particles are not fixed and are fixed with a weak force, and the boundary between particles fixed with a weak force can be confirmed with an electron microscope. Including.

As will be described in detail later, the modeling method of the present embodiment is heated at a temperature at which the particles contained in the second powder are sintered or melted, whereby the first particles in the modeling region S are heated by the second particles 2. It is characterized in that the first powder in the non-modeling region N is removed after the particles 1 are fixed.

Using the second powder containing the second particles 2 having an average particle diameter of 1 nm or more and 500 nm or less is that the sintering or melting start temperature of the second powder is compared with the sintering start temperature of the first powder. There is an effect to make it small enough. According to the experiments of the present inventors, the sintering or melting start temperature of the second powder is significantly reduced as compared with the sintering start temperature of the first powder containing the first particles having an average particle diameter of 1 μm or more. I was able to confirm. The sintering start temperature of the second powder is preferably 100 ° C. or more lower than the sintering start temperature of the first powder, and more preferably 300 ° C. or more.
The average particle diameter of the second particles 2 contained in the second powder is more preferably 1 nm or more and 200 nm or less. Hereinafter, the second particles 2 may be referred to as nanoparticles 2.
An average particle size of 200 nm or less is preferable because not only the sintering temperature is lowered, but also the dispersibility of the nanoparticles 2 in the liquid 12 is improved and the uniformity when the liquid 12 is applied is improved. .
The average particle diameter of the nanoparticles 2 is smaller than the average particle diameter of the first particles 1. Thereby, the nanoparticles 2 are filled in the gaps between the first particles 1, and the first particles 1 are easily fixed to each other by the nanoparticles 2.
The average particle diameter of the nanoparticles 2 may be set to a size that allows the nanoparticles 2 to easily enter the gaps between the first particles 1 when the liquid is applied.

As the nanoparticles 2, for example, resin particles, metal particles, ceramic particles, and the like can be used. Among these, when metal particles or ceramic particles are used as the first particles 1, it is preferable to use metal particles or ceramic particles as the nanoparticles 2. Examples of metals that can be used as the nanoparticles 2 include copper, tin, lead, gold, silver, platinum, palladium, iridium, titanium, tantalum, iron, and nickel. Further, a metal alloy such as a stainless alloy, a titanium alloy, a cobalt alloy, an aluminum alloy, a magnesium alloy, an iron alloy, a nickel alloy, a chromium alloy, a silicon alloy, or a zirconium alloy may be used as the nanoparticles 2.
Moreover, what added nonmetallic elements, such as carbon, to metals, such as carbon steel, may be used as the nanoparticle 2.
Further, as the nanoparticles 2, oxide ceramics may be used, or non-oxide ceramics may be used. Examples of oxide ceramics include metal oxides such as silica, alumina, zirconia, titania, magnesia, cerium oxide, zinc oxide, tin oxide, uranium oxide, barium titanate, barium hexaferrite, and mullite. Non-oxide ceramics include silicon nitride, titanium nitride, aluminum nitride, silicon carbide, titanium carbide, tungsten carbide, boron carbide, titanium boride, zirconium boride, lanthanum boride, molybdenum silicide, iron silicide, barium silicide, etc. Can be mentioned. The nanoparticles 2 may be composite particles of a plurality of types of metals or composite particles of a plurality of types of ceramics.

The nanoparticle 2 preferably contains at least one type of the same component as the first particle 1. By containing the same component, the surface of the nanoparticle 2 and the surface of the first particle 1 are easily bonded when the nanoparticle 2 is sintered, and the first particle 1 can be firmly fixed. Furthermore, it is more preferable that the nanoparticles 2 are composed mainly of components contained in the first particles 1. When the final shaped object is a mixture of the first particles 1 and the nanoparticles 2, if the nanoparticles 2 are composed of the same components (materials) as the first particles 1, the amount of impurities in the shaped object Since the material of the modeled object is homogenized, the strength and quality of the modeled object can be improved. For example, when the first particle 1 is a stainless steel alloy containing iron, iron particles, iron oxide particles, or the like can be suitably used as the nanoparticles 2.

As described above, when the composition of the first powder can be changed for each region or layer, the composition of the nanoparticles 2 and the type of the liquid 12 are changed for each region or layer according to the composition of the first powder. It may be changed every time, or the same type of liquid 12 may be used. Since the concentration and amount of the liquid 12 affect the porosity of the modeled object, it may be determined according to the required porosity of the modeled object.

It is preferable to provide a step of drying the liquid 12 between the step of applying the liquid 12 to the powder layer 11 and (Step 3). The step of drying the liquid 12 is preferably performed for each layer. The liquid 12 that is gradually concentrated as the drying proceeds gathers at the grain boundaries between the first particles 1 due to the surface tension. As the liquid 12 moves, the nanoparticles 2 in the liquid selectively gather at the grain boundaries between the first particles 1 and aggregate. As a result of the drying process, the nanoparticles 2 are accumulated at the grain boundaries of the first particles 1, whereby the first particles 1 can be efficiently and firmly fixed during the sintering of the nanoparticles 2 described later. When drying the liquid, it is preferable to select the optimum drying conditions such as temperature and time according to the concentration and amount of the liquid 12.

Further, in order to increase the uniformity of the liquid 12, a solvent may be added. As a specific solvent, an aqueous solvent, an organic solvent, or a mixed solvent of an aqueous solvent and an organic solvent can be used. As the aqueous solvent, pure water or the like can be used. As the organic solvent, alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone, acetone and acetyl acetone, hydrocarbons such as hexane and cyclohexane, and the like are used. When a solvent is added to the liquid 12, the solvent is evaporated at an appropriate speed during drying, and thus dispersion of the nanoparticles 2 tends to hardly occur.

In order to control the dispersibility of the nanoparticles 2 in the liquid 12, an additive may be added as appropriate. The liquid 12 may contain a functional substance such as a pigment as necessary.
The liquid 12 may also contain a binder for fixing the particles. An existing substance can be used as the binder, but the substance decomposed by the heat treatment described later (step 3), that is, the substance having a decomposition temperature lower than the temperature at which the nanoparticles are sintered or melted. Is preferred. By being decomposed by heating, the first particles 1 in the modeling region S and / or the nanoparticles 2 in the modeling region S can be fixed up to (step 3), but can be removed in (step 3). Difficult to become impurities in the model. Specific examples of the binder include resin materials and water-soluble carbohydrates. The binder is preferably dissolved in the liquid.

In addition, the application of the binder may be separated from the application process of the liquid 12, and a process of applying the binder to the powder layer 11 may be provided after (Process 2) and before (Process 3). In this case, the binder can be applied to the modeling region S or / and the non-modeling region N. By applying the binder, the first particles 1 can be temporarily fixed, and the next powder layer formation tends to be facilitated. As a method of applying the binder, a method of applying a liquid binder obtained by dissolving the binder in a liquid using a liquid application device is preferable. As the liquid binder, a resin solution in which a resin material is dissolved in a solvent, a solution in which a water-soluble substance is dissolved in water, or the like can be used.
If the liquid 12 in which the nanoparticles are dispersed and the liquid containing the binder are applied separately, the liquid can be optimized independently according to the liquid applied to each application apparatus, and thus the durability of the application apparatus Tends to be excellent, which is preferable.

The binder contributes to fixing the first particles 1 and / or the nanoparticles 2 in the modeling region S while performing (Step 2), and is decomposed and removed by heating in (Step 3). Accordingly, the binder applied in the modeling region S maintains the shape of the modeled object during (Step 2), and is decomposed by heat in (Step 3), and the decomposed product creates gaps between the first particles. Removed through. As a result, the binder is unlikely to remain as an impurity in the modeled object, and the first particles 1 in the non-modeled region N can be easily removed. It is preferable to determine the type and amount of the binder so that no binder remains.

As the liquid application device used for applying the liquid 12 or the liquid binder, any device can be used as long as it can apply the liquid in a desired amount at a desired position. An inkjet apparatus can be preferably used from the viewpoint that the liquid amount and the arrangement position can be controlled with high accuracy.
When the liquid 12 that is a particle dispersion and the liquid binder are separately applied, the application of the particle dispersion 12 to the modeling area S is performed by an ink jet apparatus having a head provided with a nozzle for discharging each liquid. A configuration in which the liquid binder is applied at a time is also preferable.

When discharging with an ink jet apparatus, the viscosity of the liquid 12 needs to be an appropriate value, preferably 50 cP or less, more preferably 20 cP or less. On the other hand, in order to quickly diffuse the liquid 12 between the first particles 1 and to aggregate the liquid 12 between the first particles 1 during drying, it is necessary to set the viscosity of the liquid 12 to an appropriate value. However, it is in the tendency which becomes easier to control fluid composition discharge because it is 20 cP or less.

In order to increase the volume density of the modeled object and increase the strength, the volume concentration of the nanoparticles 2 in the liquid 12 is preferably higher within the above viscosity range. However, in the process of drying the liquid 12, it is desirable that the volume concentration of the liquid 12 is low in terms of facilitating the accumulation of the nanoparticles 2 near the contact point between the first particles 1. From these conditions, the volume concentration of the liquid 12 is preferably 50 vol% or less, and more preferably 30 vol% or less. The solid content concentration of 50 vol% or less is preferable because the nanoparticles 2 tend to accumulate between the first particles 1 when the liquid 12 dries, and contributes to the fixation of the first particles 1 efficiently. .
The liquid 12 may be applied a plurality of times, or may be dried every time it is applied. By applying a plurality of times, the concentration of the nanoparticles 2 in the powder layer 11 in the modeling region can be controlled.

(Step 3) Step of sintering or melting the second powder and fixing the first particles in the modeling region In this step, the powder layer 11 is heated under the condition that the second powder is sintered or melted. By doing so, the 1st particle | grains 1 in the modeling area | region S are fixed through the nanoparticle 2 to sinter or fuse | melt (FIG. 1C, FIG. 1F, FIG. 2F).

In FIG. 1C and FIG. 1F, reference numeral 13 denotes a region where the particles are fixed. In the modeling process of FIGS. 1A to 1H, (Step 1) to (Step 3), that is, FIGS. 1D to 1F are repeated, and the powder layer is laminated while fixing only the particles in the modeling region S. The laminated body 14 which contains a thing inside is formed. 2A to 2G, (Step 1) and (Step 2), that is, FIGS. 2C to 2D are repeated, and the powder layer in a state where the nanoparticles 2 are provided in the modeling region S is laminated. After that, the laminate 16 composed of a plurality of powder layers is heated together. Also in this modeling process, the laminated body 14 which contains a modeled object inside is formed like FIG. 1G. In addition, before heating the laminated body 16, you may provide the process of pressurizing the laminated body 16. FIG. This is because pressurizing the laminate 16 increases the number of contacts between the first particles 1, and the interparticle binding during heating tends to proceed efficiently.

The atmosphere during heating can be arbitrarily determined according to the type of material. For example, in the case of metal, it is preferable to heat in an inert gas such as Ar or N2, an atmosphere with less oxygen, such as a hydrogen gas atmosphere or a vacuum atmosphere, because oxidation of the metal during sintering can be suppressed.
In the process of Step 3, since the organic component and the resin can be removed by heat in the situation where the first particles exist around, the remaining carbon component in the modeled object is maintained while maintaining the shape of the modeled object. Can be reduced. In particular, even when modeling shapes having different thicknesses are mixed in the modeled object, the organic component and the resin component inside can be removed, and thus the degree of freedom in the shape of the modeled object is excellent.

(Step 4) Step of removing first particles outside the modeling region In this step, the powder outside the modeling region S is removed from the laminate 14 obtained in (Step 3) to obtain a modeled object 15 (FIG. 1F, FIG. 2G). Any method including a known method may be used as a method for removing unnecessary powder from the laminate 14. For example, cleaning, air spraying, suction, vibration, etc. can be mentioned.
In the modeling method of the present embodiment, the first particles 1 contained in the powder to be removed are not fixed, or even if they are fixed, the first particles 1 are weakly fixed as compared to the modeling region S. Very easy. Further, the removed powder can be collected and reused as a modeling material.

The modeling method of this embodiment described above has the following characteristics.
Rather than directly bonding the first particles 1 that are the main modeling material, the nanoparticles 2 are sintered or melted, and the first particles 1 that are present around them are indirectly bonded by the bonding action of the nanoparticles 2. To join. Therefore, the shape of the shaped article can be controlled by controlling the position and the range to which the nanoparticles 2 are applied. Moreover, in order to apply the nanoparticles 2 in the state of the particle dispersion 12, the position, range, amount, etc., to which the nanoparticles 2 are applied can be easily and accurately controlled by using a liquid application device such as an ink jet device. Can do.

・ Since the nanoparticles 2 are sintered or melted, the first particles 1 can be firmly bonded to each other. Moreover, since the nanoparticle 2 has the effect | action which fills the clearance gap between the 1st particle | grains 1, the porosity of a molded article can be reduced.

In (Step 3), the location where the nanoparticles 2 are present is selectively fixed, so that the removal of the particles in the non-modeling region N is easy. Moreover, since it is not necessary to apply big force when removing the particle | grains of the non-modeling area | region N, there is little possibility that a modeling thing will be damaged or damaged.

-Since the first particles 1 outside the modeling region S remain in the form until just before (Step 4), if there is an overhang structure, the first particles 1 under the overhang structure are It can be used as a support body. Thereby, a deformation | transformation and crack of a molded article can be suppressed. And the 1st particle | grains 1 utilized as a support body are easy to remove. Therefore, according to the modeling method of the present embodiment, it is possible to easily and with high quality modeling complex shapes and fine shapes that have been difficult to model with conventional methods using materials such as metals and ceramics. .

When the laminate 16 is formed as shown in FIGS. 2A to 2G and heated together, the entire model is heated uniformly. Accordingly, local thermal shock is reduced, and distortion and cracking during the formation of the molded article are reduced.

・ Since modeling is possible without using resin, shrinkage and deformation of the modeled object due to degreasing can be avoided. Further, even if a resin is not used or a resin is used, a molded article with few impurities can be produced by removing it in step 2.

The above-described (Step 1) to (Step 4) are merely examples of basic steps in the modeling method of the present embodiment, and the scope of the present invention is not limited to the above-described contents. The specific processing content of each process described above may be changed as appropriate, or a process other than each process described above may be added.

For example, after (Step 4), a step of heating the shaped article 15 at a temperature higher than the heating temperature in (Step 3) may be provided. By performing such additional heat treatment, the density of the shaped article 15 can be increased. In this case, you may heat the modeling thing 15 on the conditions (heating temperature, heating time, etc.) which the 1st particle | grains 1 sinter. By sintering the first particles 1, the characteristics of the shaped article 15 can be improved and the strength can be further increased. The shaped article 15 obtained by the method of the present embodiment is basically composed only of a shaping material (first particles 1 and nanoparticles 2), and a binder such as a resin binder like the shaped article of the conventional method. May not be included. Therefore, even if the shaped article 15 is additionally heated (sintered), the composition change of the shaped article 15 is small before and after the heat treatment. Further, in the conventional method, there is a possibility that the shape of the modeled object changes when the resin is degreased by heat treatment. However, in the case of the modeled object 15 of the present embodiment, such a problem hardly occurs.

(Production method of particles)
The first particles 1 and the nanoparticles 2 may be produced by any method including a known method. For example, as a method for producing metal particles, a gas atomization method and a water atomization method can be preferably used in that substantially spherical particles can be obtained. In addition, as a method for producing ceramic particles, in terms of obtaining substantially spherical particles, a wet method such as a sol-gel method or a dry method in which a metal oxide liquefied in a high temperature air is cooled and solidified. The production method can be preferably used.

(Production method of particle dispersion)
The particle dispersion 12 may be produced by any method including a known method as long as a large number of nanoparticles 2 can be dispersed in the solution. For example, you may produce by adding the nanoparticle 2 in a solution and stirring.

(Example)
Next, specific examples of the manufacturing method according to the above embodiment will be described.
<Preparation of powder A>
SUS powder (SUS316L manufactured by Epson Atmix Co., Ltd.) containing SUS particles having an average particle diameter of 7 μm is designated as powder A.
<Preparation of powder B>
SUS powder (SUS316L LPW) containing SUS particles having an average particle diameter of 30 μm is designated as powder B.
<Preparation of powder C>
Powder (SUS316L manufactured by Sanyo Special Steel Co., Ltd.) containing SUS particles having an average particle diameter of 11 μm is designated as powder C.
<Preparation of powder D>
A copper powder containing copper particles having an average particle diameter of 8 μm (SFR-Cu manufactured by Nippon Atomizing Co., Ltd.) is designated as powder D.

<Preparation of solution A>
A solution A was obtained by dispersing 5.0 g of iron nanoparticle powder (manufactured by Sigma Aldrich) having an average particle size of 25 nm in 45.0 g of ethanol (special grade Kishida Chemical Co., Ltd.). The volume concentration of the iron nanoparticles in the obtained solution A was 1.1 vol%. Solution A had a viscosity of 1.2 cP.

<Preparation of solution B>
5.0 g of ethylcellulose (STD-4, manufactured by Nisshin Kasei Co., Ltd.) was added to and mixed with 45.0 g of ethanol (special grade Kishida Chemical Co., Ltd.), followed by stirring at room temperature for 7 hours to obtain Solution B. The volume concentration of ethylcellulose in the obtained solution B was 8.1 vol%. Solution B had a viscosity of 12.2 cP.

<Preparation of solution C>
0.007 g of ethyl cellulose (STD-4 manufactured by Nisshin Kasei Co., Ltd.) was added to 0.493 g of ethanol (special grade Kishida Chemical Co., Ltd.), mixed, and stirred for 7 hours at room temperature to obtain Solution C. The volume concentration of ethyl cellulose in the obtained solution C was 1.1 vol%.
<Preparation of solution D>
Iron nanocolloid (H10, manufactured by Tateyama Machine Co., Ltd.) was used as Solution D. Solution D is a dispersion of iron nanoparticle powder having an average particle diameter of 3.6 nm in n-hexane so as to have a volume concentration of 0.9 vol%. Solution D had a viscosity of 0.5 cP.
<Preparation of solution E>
A silver ink (NBSIJ-KC01 manufactured by Mitsubishi Paper Industries Co., Ltd.) in which silver nanoparticles were dispersed in water was used as Solution E. Solution E contained silver nanoparticles with an average particle diameter of 34 nm, and the volume concentration was 0.8 vol%. The viscosity was 4.0 cP.
<Preparation of solution F>
A nickel nanoparticle aqueous dispersion having an average particle diameter of 160 nm prepared by a liquid phase reduction method was used as Solution F. The volume concentration of nickel nanoparticles in the obtained solution F was 0.6 vol%. The viscosity was 7.1 cP.

<Measurement of sintering start temperature>
The firing start temperature of each powder was obtained by the following procedure.
An alumina container having a diameter of 5 mm and a height of 2.5 mm is packed with an amount of powder so that the bottom is not visible. The alumina container was heated in an electric furnace for 60 minutes, and the state of the powder was observed. When the sintering of the powder cannot be confirmed, heating is further performed under a condition where the temperature is increased by 10 ° C. and observation is repeated, and the temperature at which the sintering of the powder is confirmed is set as the sintering start temperature of the powder.
Whether it was sintered or not was confirmed by the following method.
Before heat treatment, an electron microscope is used to determine a field of magnification at which two or more particles having an average particle size contained in the powder are approximately within the field of view, and SUS particles contained in the powder after heat treatment are 30 places at the above magnification. Observed above. When particles with an average particle size (less than the average particle size) are bonded in the observation field of more than half, and the particles are fixed (bonded) until the boundary between the original particles can no longer be observed, It was judged that it was sintered.
Moreover, the same experiment was performed about the powder of the iron nanoparticle (made by Sigma-Aldrich) whose average particle diameter is 25 nm, and sintering start temperature was acquired. The sintering start temperature of the iron nanoparticle powder is 500 ° C. or lower, compared with the sintering start temperature 800 ° C. of the powder (powder B) of SUS316L (melting point 1400 ° C.) having a melting point lower than that of iron (melting point 1538 ° C.). But it was significantly lower. When the solution D was dried and the same experiment was performed on the silver nanoparticles, the sintering start temperature was 300 ° C. or lower.

Hereinafter, an example will be described in which a shaped object having a desired shape is manufactured by applying the solution A, the solution B, or the solution D to the powder layer formed of the powder A or the powder B and performing a heat treatment.
<Example 1>
The embodiment will be described with reference to FIG.
After forming a powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm on the alumina substrate using the powder A (step S301), the solution A was applied to a 6 mmΦ region so as to have a penetration depth of 2 mm (step S302). . The obtained powder layer was put into an electric furnace and heat-treated at 600 ° C. for 1 hour at a temperature not less than the sintering start temperature of the iron nanoparticle powder and less than the sintering start temperature of the SUS particle powder (step S303). Of the powder layer after the heat treatment, the SUS particles in the portion to which the solution A was applied (corresponding to the modeling region S) were solidified by the iron nanoparticles. By removing the SUS particles in the portion where the solution A was not applied (corresponding to the non-modeling region N) (step S304), a plate-shaped modeled object could be obtained.

<Example 2>
Referring to FIG. 5, a powder layer of 20 mm × 10 mm and a thickness of 2 mm is formed on an alumina substrate using powder A (step S401), and then the solution D is penetrated into an area of 6 mmΦ to a penetration depth of 2 mm. (Step S402). The obtained powder layer was put into an electric furnace, and heat-treated at 600 ° C. for 1 hour at a temperature higher than the sintering start temperature of iron nanoparticles and lower than the sintering start temperature of SUS particles (step S403). Of the powder layer after the heat treatment, the SUS particles in the portion to which the solution D was applied (corresponding to the modeling region S) were solidified by the iron nanoparticles. By removing the SUS particles in the portion where the solution D was not applied (corresponding to the non-modeling region N) (step S404), a plate-shaped modeled object could be obtained.

<Example 3>
Referring to FIG. 6, a first powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm was formed using powder B (step S501), and then solution D was applied to a range of 10 mm × 10 mm (step S502). Next, a second powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm is formed on the first powder layer using the powder B (step S503), and the penetration depth is 2 mm over the entire second powder layer. Solution D was applied until it became (step S504) to obtain a laminate. The obtained laminate was put in an electric furnace and heat-treated at 700 ° C., which is a temperature not lower than the sintering start temperature of iron nanoparticles and lower than the sintering start temperature of SUS particles, for 1 hour (step S505). In the laminated body after the heat treatment, the SUS particles in the portion to which the solution D was applied (corresponding to the modeling region S) were solidified by the iron nanoparticles. A desired shaped article could be obtained by removing the SUS particles in the portion (corresponding to the non-modeling region N) where the solution D was not applied (step S506). The obtained shaped object had an overhang structure in which the second layer was larger than the first layer.

<Example 4>
Modeling was performed in the same procedure as in Example 3. First, a first powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm was formed using the powder B, and then the solution F was applied to a range of 10 mm × 10 mm. Next, a second powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm is formed on the first powder layer using the powder B, and the solution F is obtained until the penetration depth becomes 2 mm over the entire second powder layer. Was added to obtain a laminate. The obtained laminate was put in an electric furnace and heat-treated at 700 ° C., which is a temperature not lower than the sintering start temperature of nickel nanoparticles and lower than the sintering start temperature of SUS particles, for 1 hour. In the laminated body after the heat treatment, the SUS particles in the portion to which the solution F was applied (corresponding to the modeling region S) were solidified by the nickel nanoparticles. The desired shaped article could be obtained by removing the SUS particles in the portion where the solution F was not applied (corresponding to the non-modeling region N). The obtained shaped object had an overhang structure in which the second layer was larger than the first layer.

According to Examples 1 to 4, iron nanoparticles are imparted to a desired region of a powder layer formed of powder made of SUS particles, and the iron nanoparticles are sintered, thereby obtaining a shaped article having a desired shape using SUS particles. It was confirmed that it was possible.

As a comparative example, modeling was performed by solidifying powder with a conventional resin binder.
<Comparative Example 1>
After forming the 1st powder layer of 20 mm x 10 mm and thickness 2mm using the powder B, the solution B was provided to the range of 10 mm x 10 mm. Next, a second powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm is formed on the first powder layer using the powder B, and the solution B is used until the penetration depth becomes 2 mm over the entire second powder layer. To obtain a laminate that is a resin-metal composite. After removing the powder B in the region where the solution B was not applied from the obtained laminate, the laminate was placed in an electric furnace and heated at a temperature equal to or higher than the sintering start temperature of the SUS particles to obtain a shaped article. .

In this method, when the powder B in the region where the solution B was not applied was removed, a part of the resin-metal composite was damaged. Further, damage was confirmed even in a part of the finally obtained metal model, and warping was confirmed in a part of the model. In this method, an overhang structure could not be formed, and a desired shaped article could not be obtained.

<Comparative example 2>
After forming the 1st powder layer of 20 mm x 10 mm and thickness 2mm using the powder B, the solution B was provided to the range of 10 mm x 10 mm. Next, a second powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm is formed on the first powder layer using the powder B, and the solution B is used until the penetration depth becomes 2 mm over the entire second powder layer. To obtain a laminate that is a resin-metal composite. The obtained laminate was put in an electric furnace as it was and heat-treated at a temperature not lower than the decomposition temperature of ethyl cellulose and lower than the sintering start temperature of SUS particles for 1 hour. The laminate after the heat treatment was still in a powder state (a state in which particles were not bonded), and a desired shaped article could not be obtained.

<Comparative Example 3>
After forming the 1st powder layer of 20 mm x 10 mm and thickness 2mm using the powder B, the solution B was provided to the range of 10 mm x 10 mm. Next, a second powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm is formed on the first powder layer using the powder B, and the solution B is used until the penetration depth becomes 2 mm over the entire second powder layer. To obtain a laminate that is a resin-metal composite. The obtained laminate was directly put into an electric furnace and heat-treated at a temperature equal to or higher than the sintering start temperature of SUS particles for 1 hour. The SUS particles in any of the region to which the solution B was applied and the region to which the solution B was not applied were sintered, and a metal sintered body was formed in the entire laminate, and a desired shaped article was not obtained.

<Comparative example 4>
After forming a first powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm using the powder B, the solution D was applied to a range of 10 mm × 10 mm. Next, a second powder layer having a thickness of 20 mm × 10 mm and a thickness of 2 mm is formed on the first powder layer using the powder B, and the solution D is obtained until the penetration depth is 2 mm over the entire second powder layer. Was added to obtain a laminate. The obtained laminate was placed in an electric furnace as it was and heat-treated at a temperature lower than the sintering start temperature of the iron nanoparticles for 1 hour. The laminate after the heat treatment was still in a powder state (a state in which particles were not bonded), and a desired shaped article could not be obtained.

<Example 5>
A first powder layer having a diameter of 15 mmφ and a thickness of 400 μm was formed using the powder B, and then a solution E was discharged using an inkjet head to draw a circular pattern of 15 mmφ.
Next, a second powder layer of 15 mmφ and a thickness of 400 μm is formed on the first powder layer using the powder B, and the solution E is ejected on the second powder layer using an inkjet head. A character pattern was drawn to obtain a laminate.
The obtained laminate was put in an electric furnace and heat-treated at 650 ° C., which is a temperature not lower than the sintering start temperature of silver nanoparticles and lower than the sintering start temperature of SUS particles, for 3 hours.
In the laminated body after the heat treatment, the SUS particles in the portion to which the solution E was applied (corresponding to the modeling region S) were solidified by the silver nanoparticles.
The desired shaped article could be obtained by removing the SUS particles in the portion where the solution E was not applied (corresponding to the non-modeling region N).

<Example 6>
A first powder layer having a diameter of 15 mmφ and a thickness of 400 μm was formed using the powder D, and then a solution E was discharged using an inkjet head to draw a circular pattern of 15 mmφ.
Next, a second powder layer having a thickness of 15 mmφ and a thickness of 400 μm is formed using the powder D on the first powder layer, and the solution E is ejected onto the second powder layer using an inkjet head. A character pattern was drawn to obtain a laminate.
The obtained laminate was put in an electric furnace and heat-treated at 300 ° C., which is a temperature not lower than the sintering start temperature of silver nanoparticles and less than 400 ° C. of copper particles, for 1 hour.
The copper particle of the part (equivalent to modeling area | region S) which apply | coated solution E among the laminated bodies after heat processing was solidified with the silver nanoparticle.
A desired shaped article could be obtained by removing the copper particles in the portion (corresponding to the non-modeling region N) where the solution E was not applied.

<Example 7>
After forming a powder layer having a thickness of 200 μm using the powder C, the solution E was discharged using an inkjet head, and two 2.5 mm × 25 mm rectangular patterns were drawn horizontally at an interval of 7 mm. The step of forming the powder layer on the powder layer and the discharging step of the solution E were repeated 11 times so that the rectangular pattern overlapped on the powder layer.
Subsequently, the drawing pattern was rotated by 85 ° at the center between the rectangles, and the pattern drawing step with the solution E and the powder layer forming step were repeated 12 times.
Similarly, the drawing pattern was rotated by 85 °, and the step of drawing the pattern with the solution E and the step of repeating the powder layer forming step 12 times were further repeated twice to obtain a laminate.
The obtained laminate was put in an electric furnace and heat-treated at 650 ° C., which is a temperature not lower than the sintering start temperature of silver nanoparticles and lower than the sintering start temperature of SUS particles, for 1.5 hours.
In the laminated body after the heat treatment, the SUS particles in the portion to which the solution E was applied (corresponding to the modeling region S) were solidified by the silver nanoparticles.
The desired shaped article could be obtained by removing the SUS particles in the portion where the solution E was not applied (corresponding to the non-modeling region N). The obtained model was further heated for 1 hour (1 hr) at 1300 ° C., which is equal to or higher than the sintering start temperature of SUS particles, in an atmosphere of Ar 97% and hydrogen 3%.
The obtained shaped object had an overhang structure with a plurality of rectangular parallelepipeds. Moreover, the strength was higher than before heating at 1300 ° C. due to sintering of the SUS particles.

From the examples and comparative examples described above, it can be seen that according to the modeling method of the present embodiment, a model including a complicated shape such as an overhang structure can be easily manufactured without forming a support body. Subsequently, further embodiments of the modeling method and the modeling apparatus of the present invention will be described.

<Example 8>
FIG. 7 shows a modeling apparatus according to the eighth embodiment. This modeling apparatus includes a powder supply unit 103 that stores and supplies powder, a layer thickness regulating blade 105, a liquid supply unit 104 that stores a particle dispersion, a liquid application unit 106 that applies a particle dispersion, and a powder layer. And a heater 102 for heating. The powder supply unit 103, the layer thickness regulating blade 105, the liquid supply unit 104, the liquid application unit 106, and the heater 102 are provided in a movable head. Further, the modeling apparatus includes a drive mechanism 201 that moves the head in the direction of the arrow in FIG. 7 and a stage 107 on which a modeled object being manufactured is arranged and is movable up and down. Although only the stage 107 is shown in FIG. 7, the powder layer is formed in a container having a wall surface (not shown) whose height from the stage is variable depending on the amount of powder. The same applies to Examples 9 to 15 below. The drive mechanism 201 is composed of, for example, a ball screw and a motor. Although FIG. 7 shows the uniaxial drive mechanism 201, a multi-axis drive mechanism may be provided so that the head can be scanned in multiple directions. For example, an ink jet device can be preferably used as the liquid application unit 106. In this embodiment, the powder supply unit 103 and the layer thickness regulating blade 105 constitute a powder layer forming unit that forms a powder layer using the first powder, and the liquid supply unit 104 and the liquid application unit 106 are powders. An application means for applying the second powder to the layer is constituted. In addition, the heater 102 constitutes a heating unit that heats the powder layer.

Before starting modeling, the first powder composed of the first particles 1 is supplied to the powder supply unit 103, and the particle dispersion containing the second powder (second particle 2) is supplied to the liquid supply unit 104, respectively. Store. In addition, the base substrate 101 is set on the stage 107. Subsequently, the first powder is supplied from the powder supply unit 103 onto the base substrate 101, and the surface thereof is leveled by the layer thickness regulating blade 105, whereby the powder of the first powder having a thickness of 100 μm is formed on the base substrate 101. Form a layer. This powder layer is a layer underlying the laminate 108 and is hereinafter referred to as a “base layer”.

Next, based on the thickness defined by the slice data, the amount of the first powder for one layer is supplied from the powder supply unit 103 onto the base layer, and the surface is leveled by the layer thickness regulating blade 105, A powder layer of the first powder is formed. Thereby, the powder layer for 1 slice of a molded article is formed.

Next, using the liquid application unit 106, the solution A is applied to the modeling region S in the powder layer based on the cross-sectional shape of the modeling target defined by the slice data. The amount of liquid at this time is controlled so that the dispersion liquid in which the second powder is dispersed penetrates to a depth substantially equal to the thickness of the powder layer. Thereby, a powder layer in which the second particles 2 enter the gap between the first particles 1 in the modeling region S is formed. Next, by using the heater 102, at least a part of the first particles are not sintered, and the powder layer is heated and sintered or melted under the condition that the second particles are sintered or melted. The first particles are fixed by the second particles.

Based on the slice data of each layer, by repeating a series of processes such as formation of the powder layer of the first powder, application of the dispersion, and heating of the powder layer for each layer, the laminate 108 in which a plurality of powder layers are stacked. Is produced. Thereafter, the first powder in the non-modeling region N is removed from the laminate 108, whereby a modeled object having a desired shape is obtained.

According to the modeling apparatus of the present embodiment, a modeled object including an overhang structure and a fine structure can be manufactured with high quality. In addition, since a series of processes of forming the powder layer with the first powder, arranging the second powder, and heating the powder layer can be performed in one scan, high-speed modeling is possible, and Miniaturization can be achieved. In addition, since the base layer is laid between the base substrate 101 and the modeled object, no special processing for removing the modeled object from the base substrate 101 is required.

<Example 9>
FIG. 8 shows a modeling apparatus according to the ninth embodiment. The difference in configuration from Example 8 is that instead of providing the heater 102, a heating area (heating chamber) 110 for heating the entire laminate is provided.

In the same manner as in Example 8, a base layer having a thickness of 100 μm is formed on the base substrate 101. Next, based on the thickness defined by the slice data, the amount of the first powder for one layer is supplied from the powder supply unit 103 onto the base layer, and the surface is leveled by the layer thickness regulating blade 105, A powder layer is formed. Thereby, the powder layer for 1 slice of a molded article is formed. Next, using the liquid application unit 106, a dispersion liquid in which the second powder is dispersed is applied to the modeling region S in the powder layer based on the cross-sectional shape of the modeling object defined by the slice data. The liquid amount at this time is controlled so that the dispersion liquid penetrates to a depth substantially equal to the thickness of the powder layer. Thereby, a powder layer in which the second particles 2 enter the gap between the first particles 1 in the modeling region S is formed.

Based on the slice data of each layer, a plurality of powder layers are formed by repeating formation of a powder layer composed of the first powder (first particles) and application of a dispersion containing the second powder (second particles). A laminated body 109 in which is stacked is produced. Then, the laminated body 109 is moved to the heating area 110, and the laminated body 109 is heated under the condition that at least a part of the first particles are not sintered and the second particles are sintered or melted. . Thereby, the second particles are sintered, and the first particles in the modeling region S are fixed by the sintered or melted second particles. Thereafter, by removing the first powder in the non-modeling region N from the laminate 109, a modeled object having a desired shape is obtained.

According to the modeling apparatus of the present embodiment, a modeled object including an overhang structure and a fine structure can be manufactured with high quality. In addition, since the entire laminated body 109 is heated not for each layer, the entire laminated body 109 can be heated uniformly during the heat treatment, local thermal shock is reduced, and distortion and cracking during formation of the shaped object are suppressed. The In addition, since a series of processes of forming the powder layer composed of the first particles 1 and arranging the second particles 2 can be performed by one scan, high-speed modeling is possible and the modeling apparatus is downsized. Can be achieved. In addition, since the number of heat treatments can be significantly reduced as compared with the case where heat treatment is performed for each layer, the modeling time can be shortened. In addition, since the base layer is laid between the base substrate 101 and the modeled object, no special processing for removing the modeled object from the base substrate 101 is required.

<Example 10>
In Example 10, after the dispersion liquid containing the second powder (second particle) is applied to the powder layer, the solution A is dried by allowing to stand for 1 minute. Other modeling processes may be the same as those in Example 8 or Example 9. Further, the configuration of the modeling apparatus may be the same as that of the eighth embodiment or the ninth embodiment. Since the penetration of the dispersion liquid can be controlled by providing the drying step, it is possible to produce a shaped object with higher accuracy than the above-described embodiment. Further, by providing the drying step, the second particles 2 accumulate at the grain boundaries of the first particles 1, thereby making it possible to produce a shaped article having higher strength than the above-described embodiment.

<Example 11>
FIG. 9 shows a modeling apparatus according to the eleventh embodiment. The difference in configuration from the ninth embodiment is that a drying heater 111 is provided between the powder supply unit 103 and the liquid application unit 106. The drying heater 111 is a drying auxiliary means for promoting the drying of the dispersion liquid containing the second powder (second particles) applied to the powder layer. In the present embodiment, after the powder layer is formed, the powder layer is heated by the drying heater 111. Thereafter, the dispersion A is applied to the heated powder layer. With such a configuration, the drying of the solvent contained in the dispersion liquid is promoted compared to the natural drying as in Example 10, the drying time can be shortened, and the modeling time can be shortened. In FIG. 9, the drying assist means is provided in the front stage of the liquid applying unit 106, but the drying assist means (such as a heater) may be provided in the subsequent stage of the liquid applying unit 106.

<Example 12>
FIG. 10 shows a modeling apparatus according to the twelfth embodiment. A difference in configuration from the ninth embodiment is that a pressurizing unit 112 is provided between the powder supply unit 103 and the liquid application unit 106. As the pressure unit 112, a pressure roller as shown in FIG. 10 or a pressure plate may be used. In this embodiment, after the powder layer of the first powder is formed, the powder layer is pressurized by the pressurizing means 112. By pressurizing the powder layer, the particles of the first powder come into close contact with each other, so that the porosity and defects of the shaped article can be reduced and the mechanical strength of the shaped article can be increased.

<Example 13>
In the thirteenth embodiment, a modeled object (in a state where unnecessary particles are removed) is arranged in the heating area 110, and the modeled object is heated under a condition in which SUS particles can be sintered. Thereby, since sintering of the SUS particle | grains which are the main materials of a molded article advances, the space | gap of a molded article decreases and the mechanical strength of a molded article can be raised further.

<Example 14>
FIG. 11 shows a modeling apparatus according to the fourteenth embodiment. The difference in configuration from Example 9 is that a second liquid application unit 113 for discharging a binder is provided after the liquid application unit 106 for discharging the second powder dispersion.

Before starting modeling, the first powder composed of the first particles 1 is contained in the powder supply unit 103, the solution containing the second particles 2 (nanoparticles) is contained in the liquid supply unit 104, and the resin binder is contained. Each of the liquid binders is stored in the liquid supply unit 114.

In the same manner as in Example 9, a base layer having a thickness of 100 μm is formed on the base substrate 101. Next, based on the thickness defined by the slice data, the amount of the first powder for one layer is supplied from the powder supply unit 103 onto the base layer, and the surface is leveled by the layer thickness regulating blade 105, A powder layer of the first powder is formed. Thereby, the powder layer for 1 slice of a molded article is formed.

Next, using the liquid application unit 106, a solution containing the second powder is applied to the modeling region S in the powder layer based on the cross-sectional shape of the modeling object defined by the slice data. The amount of liquid at this time is controlled so that the solution penetrates to a depth substantially equal to the thickness of the powder layer. As a result, the nanoparticles (second particles 2) enter the gaps between the first particles 1 in the modeling region S.

Next, the liquid application unit 113 is used to apply the solution C to the powder layer. Thereby, the first particles 1 are temporarily fixed with the binder.

Based on the slice data of each layer, the formation of the powder layer of the first powder and the application of the solution C are repeated for each layer, thereby producing a laminate 109 in which a plurality of powder layers are stacked. Thereafter, the laminated body 109 is moved to the heating area 110, and the laminated body 109 is heated under the condition that at least a part of the first particles are not sintered and the nanoparticles are sintered or melted. Thereby, the nanoparticles are sintered or melted, and the first particles are fixed by the sintered or melted nanoparticles. Thereafter, by removing the first particles in the non-modeling region N from the laminate 109, a modeled object having a desired shape is obtained.

In the present embodiment, since the first particles of the powder layer are also fixed by ethyl cellulose, the powder layer can be molded and laminated with high accuracy, and defects in the shaped article are reduced. In addition, since the decomposition temperature of ethyl cellulose is lower than the sintering start temperature of the nanoparticles, ethyl cellulose is decomposed during heating.
In addition, by independently applying the solution containing the nanoparticles and the solution containing the binder, each of the liquid application units 106 and 113 can be optimized independently, so that the durability of the liquid application unit Is excellent.

<Example 15>
FIG. 12 shows a modeling apparatus according to the fifteenth embodiment. The structural difference from Example 9 is that the first unit for producing the laminate 109 and the second unit for heating the laminate 109 are provided separately.
With such a configuration, it is not necessary to shield the heating area 110 as compared with the ninth embodiment, so that the apparatus can be downsized.
Moreover, since the production of the laminate 109 and the heating of the laminate 109 can be performed at the same time, the shaping speed is improved when producing a plurality of shaped objects.

(Other)
The present invention has been described above with specific embodiments. However, the present invention is not limited to the above embodiments, and various modifications may be made without departing from the technical idea of the present invention. For example, in the above embodiment, only the second particles 2 are selectively sintered or melted by controlling the temperature of the heat treatment, but by appropriately controlling the time of the heat treatment or both the temperature and the time. Only the second particles 2 may be selectively sintered or melted. Moreover, in the said Example, although the arrangement | positioning of the 2nd particle | grains 2 was performed with the dispersion liquid containing a 2nd particle | grain, you may arrange | position the 2nd particle | grains 2 in a powder state instead of a liquid. In the fourteenth embodiment, the second liquid application unit 113 is provided after the liquid application unit 106, but the second liquid application unit 113 may be provided before the liquid application unit 106. Further, the liquid application unit 106 applies a solution (dispersion liquid not containing a binder) containing second particles to the modeling region S, and the second liquid application unit 113 provides both the modeling region S and the non-modeling region N. A liquid binder may be added. Further, the configurations of the first to fifteenth embodiments may be combined with each other as long as there are no technical contradictions or physical restrictions.

Claims (25)

1. Forming a powder layer using the first powder;
   Disposing a second powder having an average particle size smaller than that of the first powder in a partial region of the powder layer;
   A first heating step for heating the powder layer in which the second powder is disposed;
   Including
   The average particle size of the second powder is 1 nm or more and 500 nm or less,
   The first heating step includes heating at a temperature at which particles contained in the second powder are sintered or melted.
2. The modeling method according to claim 1, further comprising a step of removing the first powder outside the partial area after the first heating step.
3. The modeling method according to claim 2, further comprising a second heating step of heating the powder in the partial region after the step of removing the first powder outside the partial region.
4. The method further includes a second heating step of heating the powder layer so that particles contained in the first powder are sintered after the step of removing the first powder outside the partial region. The modeling method according to claim 2, wherein the modeling method is characterized.
5. The step of forming the powder layer and the step of arranging the second powder are alternately repeated a plurality of times, and then the first heating step is performed.
   The modeling method according to any one of claims 1 to 4, characterized in that:
6. 6. The modeling method according to claim 1, wherein an average particle diameter of the first powder is 1 μm or more and 500 μm or less.
7. The modeling method according to any one of claims 1 to 6, wherein an average particle diameter of the second powder is 1 nm or more and 200 nm or less.
8. The modeling method according to any one of claims 1 to 7, wherein the particles constituting the first powder and the particles constituting the second powder contain at least one same component.
9. The modeling according to any one of claims 1 to 8, wherein the particles constituting the second powder are mainly composed of components contained in the particles constituting the first powder. Method.
10. The modeling method according to any one of claims 1 to 9, wherein both the first powder and the second powder are powders containing metal or ceramic particles.
11. 11. The step of arranging the second powder is a step of applying a liquid containing the second powder to the partial region by a liquid application device. The modeling method according to 1.
12. The modeling method according to claim 11, wherein the liquid contains a binder.
13. The modeling method according to claim 12, wherein a volume concentration of the binder contained in the liquid is 50 vol% or less.
14. The modeling method according to any one of claims 11 to 13, further comprising a step of drying the liquid between the step of applying the liquid and the first heating step.
15. The modeling method according to claim 12, wherein the liquid has a viscosity of 50 cP or less.
16. The shaping according to any one of claims 1 to 15, further comprising a step of pressurizing the powder layer between the step of forming the powder layer and the step of arranging the second powder. Method.
17. The method according to any one of claims 1 to 16, further comprising a step of applying a binder to the powder layer between the step of forming the powder layer and the first heating step. Modeling method.
18. The modeling method according to claim 17, wherein the region to which the binder is applied is a region outside the partial region of the powder layer.
19. Powder layer forming means for forming a powder layer using the first powder;
    Arranging means for disposing a second powder having an average particle diameter smaller than that of the first powder in a partial region of the powder layer;
    Heating means for heating the powder layer so that particles contained in the second powder are sintered or melted;
    A modeling apparatus comprising:
20. The modeling apparatus according to claim 19, wherein the arrangement unit is a liquid application device that applies a liquid containing the second powder to the partial area.
21. The modeling apparatus according to claim 20, wherein the liquid application device is an inkjet device.
22. The modeling apparatus according to claim 20 or 21, further comprising a drying assist unit that promotes drying of the liquid applied to the partial area.
23. The modeling apparatus according to claim 22, wherein the drying assist unit is a heater that heats the powder layer before the liquid is applied.
24. The modeling apparatus according to claim 19, further comprising a pressurizing unit that pressurizes the powder layer.
25. The powder layer forming means and the arranging means are configured as a first unit,
    The modeling apparatus according to any one of claims 19 to 24, wherein the heating unit is configured as a second unit.
    

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