JP6794105B2 - Particle swarms used to manufacture three-dimensional objects, and methods for manufacturing three-dimensional objects using them - Google Patents

Description

The present invention relates to a group of particles used for producing a three-dimensional object and a method for producing a three-dimensional object using the same.

In recent years, attention has been paid to a layered manufacturing method in which modeling materials are laminated based on cross-sectional data of a three-dimensional object (modeling object) which is a modeling object.

In Patent Document 1, using an electrophotographic process, layers for arranging modeling particles (particles constituting the modeling object) and supporting particles are sequentially laminated while being fused and bonded according to the cross-sectional data of the modeling object. The method of doing so is disclosed. The modeling particles and the supporting particles each have a structure in which a bonding material is formed around the base material, and the bonding material of the modeling particles is formed thicker than the bonding material of the supporting particles. As a result, the modeling particles can be fused more firmly than the supporting particles, and the supporting particles can be easily removed after the modeling is completed.

Japanese Unexamined Patent Publication No. 10-86224

Patent Document 1 discloses the composition of each of the molding particles and the supporting particles, and the base material and the bonding material, but does not disclose any characteristics when each particle is viewed as a particle group.

However, in the additive manufacturing method using particles as a modeling material as in Patent Document 1, the particle size of the particles and the particle size distribution of the particle group have a great influence on the defects generated during the modeling process and the quality of the obtained three-dimensional object. give. Specifically, when holes or voids are formed in the layer to be laminated, there is a problem that a stacking defect occurs partially, or the obtained three-dimensional object contains voids and the density decreases.

This is done to solve the above problems, and an object of the present invention is to reduce stacking defects and to provide a three-dimensional object having a high material density.

The first aspect of the present invention is a group of particles used as a molding material in a laminated molding method, which has an average circularity of 0.80 or more, a volume-based average particle size of Dv, and a number-based average particle size. As Dn, Dv / Dn is larger than 1.3 and 23 or less, and the particles contained in the particle group contain a water-soluble thermoplastic substance.

According to the present invention, it is possible to reduce stacking defects and provide a three-dimensional object having a high material density.

It is a figure explaining the problem about the particle size distribution of a particle group. It is a graph which shows the particle size distribution of a particle group 1. It is an optical microscope image of a sheet prepared using particle group 2. It is an optical microscope image of the sheet prepared using the particle group 4. It is an optical microscope image of the sheet prepared using the particle group 5. It is the schematic of the modeling apparatus which uses the particle group which concerns on this invention as a modeling material.

Hereinafter, the present invention will be described with reference to the drawings. In each drawing, the same or corresponding members are designated by the same reference numerals. Further, a well-known technique or a known technique can be applied to matters not particularly illustrated or explained.

First, the terms used in the explanation will be explained. A three-dimensional object that is a modeling object is called a modeling object, a material that constitutes the modeling object is called a structural material, and particles made of the structural material are called structural material particles. When the object to be modeled has a structure including an overhang and a movable part, it becomes necessary to provide the structural material on the space without the structural material. Therefore, a material for supporting the structural material during manufacturing is provided in the portion that becomes such a space. This material is called a support material, and particles composed of the support material are called support material particles. When it is not possible to distinguish between the structural material and the support material, these are collectively referred to as a modeling material, and the particles thereof are referred to as modeling material particles.

An object in which a structural material and a support material are laminated based on slice data of an object to be modeled is called a modeled object. The modeled object includes a structure made of a structural material and a support body made of a support material, but the support body is a part that is unnecessary for the object to be modeled. Therefore, the three-dimensional object (structure) obtained by removing the support body from the modeled object for which the predetermined modeling has been completed is the modeled object. Since the support body may or may not be necessary depending on the shape of the object to be modeled and the stacking direction (modeling direction) thereof, the modeled object may not include the support body.

Next, a layered manufacturing method to which the particle group according to the present invention is applied will be described. The additive manufacturing method includes the following steps.
(I) Step of arranging structural material particles according to slice data to form a material layer (II) Step of melting and laminating a material layer

By repeating the steps (I) and (II) a number of times according to the slice data of the object to be modeled, the modeled object can be obtained. Hereinafter, each step will be described.

(I) Step of arranging structural material particles according to slice data to form a material layer Slice data is obtained by adding a support body based on three-dimensional data representing the structure of a modeling object and a stacking direction. This is data obtained by slicing three-dimensional data of a modeled object at regular intervals in the stacking direction. Alternatively, the support body data is added to the data obtained by slicing the three-dimensional data representing the structure of the modeling object in the stacking direction at regular intervals. Therefore, the slice data includes the arrangement of at least one of the structural material and the support material in each layer. In this step, structural material particles and support material particles are arranged according to this slice data, and a material layer is formed. It should be noted that the slice data of the modeling object having a shape that does not require a support body does not include the arrangement of the support material particles.

As a method of arranging the structural material particles and the support material particles according to the slice data, a known method such as an electrophotographic method or an inkjet method can be appropriately used.

(II) Step of Melting and Laminating the Material Layer The material layer formed by arranging at least one of the structural material particles and the support material particles is melted and laminated by heating or spraying with a binder solution or the like. Lamination of the material layer is performed on the surface of the base or on the surface of the model being made on the base. When laminating on the surface of the modeled object above the base, it is preferable to melt the material of the laminated surface of the modeled object. The concept of "melting the particle layer" includes the concept of melting the particle layer and fusing the particles contained in the particle layer.

When modeling including the steps (I) and (II) was performed using various modeling particle groups, it was found that the following problems occur when the material layer is melted.

FIG. 1 is a diagram schematically showing a state when a material layer composed of modeling material particle groups is heated. FIG. 1 (a) shows a material layer composed of a group of particles having a substantially constant particle size, and FIG. 1 (b) shows a case of a material layer composed of a group of particles in which particles having different particle sizes are appropriately mixed. Reference numeral 1 (c) is a case of a material layer composed of a group of particles in which many particles having a relatively small diameter are mixed.

As shown in FIG. 1A, in the case of a material layer composed of particles 11 having a constant particle size, there are voids 12 having a large particle size with respect to the particle size. A resin widely used as a structural material has a thermal conductivity of about 0.3 [W / mK], whereas an air has a thermal conductivity of about 0.02 [W / mK]. Therefore, the voids 12 between the particles hinder the propagation of heat when melting the particles. Therefore, within a limited time, the material layer may not be melted to a uniform thickness as shown in the right end of FIG. 1A. Such a problem is likely to occur especially when the material layer is heated from one side.

When material layers having a non-uniform thickness are laminated, voids are formed between the material layers to reduce the binding force, and stacking defects such as peeling may occur during lamination. The modeled object obtained by such lamination has low modeling accuracy and weak strength.

Further, as shown in FIG. 1 (c), in the case of a material layer formed of a group of particles in which a large amount of particles 11b having a relatively small particle size is mixed with a particle 11a having a relatively large particle size, the space between the particles. The volume of the void 12 is reduced, and the effect on heat propagation is reduced. However, in the material in which the small particles are melted, the relatively large particles 11a are attracted and aggregated by the surface tension of the melted material, and as a result, the material cannot be melted to a uniform thickness.

Therefore, it was considered that a material layer melted to a uniform thickness could be realized by forming a material layer with a group of particles in which particles having different particle sizes are appropriately distributed. Specifically, as shown in FIG. 1 (b), if a material layer is formed using a particle group in which relatively large particles 11a and small particles 11b are appropriately mixed, between particles that inhibit heat conduction. The volume of the air layer can be reduced. Further, the relatively small particles are dissolved first and spread to reduce the surface energy of the entire system, and the effect of filling the voids between the relatively large particles can be expected. As a result, it is considered that the material layer can be melted to a uniform thickness and the voids can be effectively reduced.

Therefore, a group of particles having a particle size distribution suitable for realizing a material layer having a uniform thickness after melting and performing highly accurate laminated modeling was investigated.

To examine the particle size distribution of particle groups, first, multiple types of particle groups with different particle size distributions are prepared, and a material layer is formed and melted using each particle group, and the porosity of the obtained layer is determined. evaluated. After that, modeling was actually performed using each particle group, and the appearance of the modeled object was evaluated. A method of applying thermal energy was adopted for melting the material layer.

The contents of the study will be described in detail below.

(Preparation of particle swarm)
In preparing the particle swarm, other than the particle size distribution, the conditions preferable for the additive manufacturing method were satisfied. The characteristics of particles suitable for additive manufacturing are as follows.

When a method of applying thermal energy to the material layer to melt the material layer is adopted, it is preferable that the particles contain at least a thermoplastic substance. A thermoplastic substance is a substance that does not easily change at room temperature, but exhibits plasticity when heated appropriately and can be freely deformed, and also has the property of becoming hard again when cooled. In the present invention, when the term "particles containing A" is described, there are cases where some of all the materials constituting the particles are A and cases where all the materials constituting the particles are A. In either case, it shall be included. It should be noted that the former naturally includes the case where the main component of the particles (for example, 90% by weight or more) is A.

As the thermoplastic substance, a known substance may be adopted. For example, ABS (acrylic nitrile-butadiene-styrene copolymer), PP (polypropylene), PE (polyethylene), PS (polypropylene), PMMA (polymethylmethacrylate), PET (polybutylene terephthalate), PPE (polyphenylene ether), PA (Nylon / Polyamide), PC (Polycarbonate), POM (Polyacetal), PBT (Polybutylene terephthalate), PPS (Polyphenylene sulfide), PEEK (Polyetheretherketone), LCP (Liquid crystal polymer), Fluorine resin, Urethane resin, Elastomer , PVA (polypropylene alcohol), and other examples include metals and inorganic substances. These substances may be used alone or in combination. Particles made of these materials can be suitably used as structural material particles.

Further, a thermoplastic substance suitable for producing water-soluble molding material particles is a compound having a hydroxyl group, and more specifically, a water-soluble inorganic substance, a water-soluble carbohydrate such as a water-soluble dietary fiber, etc. , Sugars, polyalkylene oxides, polyvinyl alcohols. Specific examples of the water-soluble dietary fiber include polydextrose and inulin, and specific examples of sugar include sucrose, lactose, maltose, trehalose, melezitose, stachyose, and maltotetraose. Moreover, PEG (polyethylene glycol) is mentioned as a specific example of polyalkylene oxide. When particles made of these materials are used as support material particles, the support body can be easily removed from the modeled object by contact with water, which is preferable.

In addition to the thermoplastic substance, the particles may contain a functional substance such as a pigment according to the function of the target three-dimensional model. Further, in order to improve the fluidity of the particle group, fine powder such as silica nanoparticles may be attached to the surface of the particles.

The average circularity of the particles constituting the particle group is preferably 0.80 or more, more preferably 0.90 or more. This is because when the average circularity is 0.80 or more, the particles are likely to flow and the closest packing is easily formed, and energy propagation and substance diffusion are efficiently performed.

The circularity of the particles can be measured as follows, and the average circularity can be obtained by averaging the circularity obtained by measuring 10 or more arbitrary molding particles.
Circularity = (peripheral length of a circle with the same area as the projected particle area) / (peripheral length of the projected particle image)

Here, the "particle projection area" is defined as the area of the binarized particle image, and the "peripheral length of the particle projection image" is defined as the length of the contour line obtained by connecting the edge points of the particle image. ..

The circularity is an index showing the degree of unevenness of the particles, and shows 1.00 when the particles are completely spherical, and the more complicated the surface shape, the smaller the circularity.

The circularity of the particles can be measured by image processing of an observation image such as an electron microscope and by using a commercially available flow type particle image measuring device (for example, FPIA-3000 type manufactured by Toa Medical Electronics Co., Ltd.).

The glass transition temperature, softening temperature, and melting temperature of the particles can be appropriately selected depending on the temperature at which the material layer is melted, but are preferably 40 ° C. or higher and 300 ° C. or lower.

When the temperature is 40 ° C. or higher, the obtained three-dimensional object is less likely to be deformed, and when the temperature is 300 ° C. or lower, the heat resistance required for the modeling apparatus can be lowered, and the options for the heating method in the melting process are increased.

The volume-based average particle size of the particle group is preferably 5 μm or more and 100 μm or less, and more preferably 20 μm or more and 80 μm or less. Since the average particle size based on the volume is 5 μm or more, it is possible to increase the thickness of one layer without forming a material layer by stacking a plurality of particles, and it is easy to control the film thickness of the material layer. It becomes. Further, in the particle group, the particle size range taken by particles having a relatively small particle size tends to be wide, so that the effect of filling the voids tends to be easily obtained. Further, when the particle size is 100 μm or less, it becomes easy to realize good stacking accuracy.

A known method can be used as the method for producing the particles. Specific examples include a chemical polymerization method such as a mechanical pulverization method, a melt dispersion cooling method in which particles are obtained by dispersing and cooling in a medium in a molten state, and a suspension polymerization method in which polymer particles are produced in a medium. Above all, the particle production method using a medium is preferable because the shape and particle size distribution of the particles can be controlled relatively freely.

Multiple types of particle groups were prepared within the above conditions, and the relationship between their particle size distribution and modeling was verified. The particle size distribution of the particle group was evaluated using the parameters represented by the following equation (1).
Dv / Dn ・ ・ ・ (1)

Here, Dv is the average particle size based on the volume of the particle group, and Dn is the average particle size based on the number of particle groups.

The volume-based average particle size Dv and the number-based average particle size Dn of the particle group can be measured using a commercially available laser diffraction / scattering type particle size distribution measuring device, for example, LA-950 (manufactured by HORIBA). it can. Use the attached dedicated software to set the measurement conditions and analyze the measurement data.

More specifically, first, a batch cell containing a measurement solvent is set in a laser diffraction / scattering particle size distribution measuring device, and an optical axis is adjusted and a background is adjusted. Here, it is necessary to select a solvent in which the particles do not dissolve as the solvent used for the measurement. In addition, a dispersant may be appropriately added to the solvent in order to improve the dispersion of the particles to be measured.

The particle group to be measured is added to the batch cell until the transmittance of the tungsten lamp becomes 95% to 90%, and the particle size distribution is measured. From the obtained measurement results, each of Dv and Dn can be calculated according to a known procedure.

The particle size distribution may be adjusted by controlling the production conditions of the particle group, by a method of classifying the produced particle group, or by combining these. The classification can be appropriately selected from known methods such as a method using a sieve and a method using a wind force such as an elbow jet. The produced particle group may be classified a plurality of times. Further, the particle size distribution of the particle group may be adjusted by mixing the particles obtained by the classification with the particle groups having different average particle sizes.

The following particle swarms 1 to 5 were prepared.

<Adjustment of particle swarm 1>
Polypropylene PP (Noblen W-531 manufactured by Sumitomo Chemical Co., Ltd.) was melt-kneaded at an arbitrary barrel temperature with a twin-screw extrusion kneader.

After cooling, particles were obtained by freezing and pulverizing using a hammer mill and classifying. Particle group 1 was obtained by externally adding 1 g of silica fine particles having a primary particle size of 7 nm, which was obtained by treating 100 g of the obtained particle group with silicone oil, using a coffee mill. FIG. 2 shows the particle size distribution of the particle group 1.

<Adjustment of particle swarm 2>
Polypropylene (Noblen W-531 manufactured by Sumitomo Chemical Industries, Ltd.) and polyethylene glycol (PEG # 20000 Sanyo Kasei Co., Ltd.) were mixed at a ratio of 1: 6 and melt-kneaded at a temperature of 200 ° C. Then, it was cooled, and the PEG was washed and dried with water to obtain particle group 4.

<Adjustment of particle swarm 3>
Polydextrose PD (manufactured by Starlight 3 Tate & Lyle) was crushed with a hammer mill and then classified to obtain particle group 3.

<Adjustment of particle swarm 4>
Particle group 4 was obtained in the same manner as in particle group 1 except that the classification conditions were changed.

<Preparation of particle swarm 5>
Particle group 6 was obtained by pulverizing polydextrose PD (manufactured by Starlight 3 Tate & Lyle) with a hammer mill.

Table 1 summarizes the physical properties of each of the obtained particle groups 1 to 5 as described above. In Table 1, "PP" indicates polypropylene and "PD" indicates polydextrose.

(Preparation and evaluation of material layer)
The porosity of the sheet layer obtained by forming a material layer using the produced particle groups 1 to 5, heating to melt once, and then cooling to solidify was evaluated.

First, each of the produced particle groups was filled in a cartridge of an LBP printer, and a material layer having a size of 2.0 cm × 2.0 cm was printed on a film sheet so as to have a thickness of about 70 μm. Next, a film sheet was placed on the printing surface, and the roller fixing unit of the printer was melted at a temperature of 170 degrees and a speed of 30 mm / sec with an improved fixing device so that the fixing temperature and speed could be adjusted to form a sheet. ..

The abundance ratio of voids was calculated for each sheet obtained by peeling the film sheet. The procedure for calculating the abundance ratio of voids is as follows.

Using an optical microscope, the surface of the sheet was observed at a magnification of 100 times in a field of view of 2.4 mm in length × 3.2 mm in width, and the image was saved. The obtained image was subjected to image processing in which the dark part (void part) was represented by black and the bright part (region other than the void) was represented by white. Using image analysis software, the ratio of the area of the black part in each image to the total area of each image (sum of the areas of the white and black parts) was taken, and the abundance ratio of voids [%] was taken. Table 1 shows the abundance ratio of the obtained voids.

As can be seen from the table, the sheets prepared using the particle groups 1 to 3 had few voids and had an almost transparent appearance. Among them, the sheet prepared in the particle group 1 or 2 was preferable, and the sheet prepared in the particle group 2 was particularly preferable because the voids were not conspicuous. On the other hand, in the sheets prepared using the particle groups 4 and 5, white turbidity due to voids was observed.

Optical microscope images of the sheets prepared using each of the particle groups 1, 4, and 5 are shown in FIGS. 3, 4, and 5. As can be seen from FIGS. 3 to 5, the sheet prepared by using the particle group 1 has a low frequency of occurrence of the voids 20 and the area occupied by the voids is small, and the sheet prepared by using the particle group 4 or 5 is It can be seen that the gap portion 20 is frequently generated or the area occupied by the gap is large.

(Evaluation by laminated modeling)
A material layer is formed using each of the particle groups 1 to 5, heated at 170 ° C., and then cooled. By repeating the process of sequentially laminating the material layers 20 times each, a modeled object is produced and its appearance is evaluated. did.

The voids were not conspicuous in any of the shaped objects prepared in the particle groups 1 to 3, but the shaped objects prepared in particular in the particle groups 2 had high transparency and excellent appearance. In the modeling using the particle groups 4 and 5, when the produced sheets were laminated, there were some poorly laminated parts due to voids when several sheets were laminated. In addition, the modeled object in the laminated portion was also partially clouded and inferior in appearance.

From Table 1 and the evaluation by additive manufacturing, a group of particles having an average circularity of 0.80 or more and a particle size distribution Dv / Dn larger than 1.3 and 23 or less is preferable as a modeling material for additive manufacturing, and Dv / It was found that a particle group having a Dn greater than 1.3 and 5.0 or less is more preferable.

As described above, when performing laminated modeling, a plurality of types of particles such as structural particles for forming a three-dimensional object to be modeled and support material particles depending on the shape of the object to be modeled are used for modeling. In some cases. The “plurality of particles” described here means that the particles include a plurality of particles made of materials having different chemical structures.

In such modeling using a plurality of types of particles, the temperature range in which all the plurality of types of particles can be melted is narrow, so that the temperature at the time of melting deviates from the temperature range in which all the plurality of types of particles can be melted, which is sufficient. Heat may not be transferred to. Then, the influence of the voids between the particles tends to affect the melting of the material layer. Therefore, the present invention is particularly effective for modeling using a plurality of types of particles.

When forming a material layer containing a plurality of types of particles, an electrophotographic method using electrostatic force is particularly preferable in that the degree of freedom in arranging the particles is high. As an example of a method for forming a particle layer by an electrophotographic method using electrostatic force, particles of each type are arranged on a charging drum, and each type of particles is transferred onto a base material such as a belt. Examples thereof include a method of forming a material layer composed of a plurality of types of particles. The transfer of the particles may be carried out a plurality of times, and by carrying out the transfer a plurality of times, it becomes easier for the particles to have a close-packed structure, and the effects of the present invention can be easily obtained.

It is preferable that the plurality of types of particles used for modeling satisfy the conditions that the average circularity of the particle group for each type is 0.80 or more, the particle size distribution Dv / Dn is larger than 1.3, and 23 or less. ..

As long as the particle group is composed of molding material particles, it may be composed of a single type of particles or a plurality of types of particles, but the same type of particles have the above-mentioned particle size distribution. It is preferable that the conditions are satisfied. This is because when the particles of the same type satisfy the above-mentioned particle size distribution conditions, the difference in surface energy at the time of melting is small, so that a more homogeneous model can be formed.

When laminating the material layer on the modeled object being produced, it is preferable to laminate the formed material layer on the laminated surface of the modeled object being produced. However, another material layer may be formed directly on the material layer or the melted material layer. Further, the material layer may be melted before laminating, at the same time as laminating, or after laminating, or at a plurality of timings among them.

(Application example of particle swarm optimization)
Hereinafter, an example of a method for manufacturing a three-dimensional object using the particle group according to the present invention as a structural material and a support material will be described together with a specific example of a modeling apparatus used for laminated modeling. For the formation of the material layer, a modeling apparatus using an electrophotographic method is taken as an example, but a known method such as a method using an inkjet (see International Publication No. 2014/092205) can be used.

FIG. 6 is a configuration example of the modeling apparatus 500 used for laminated modeling. The modeling apparatus 500 includes a material layer forming portion 501, a modeling portion 502, and a transport body 24 connecting the material layer forming portion and the modeling portion.

The material layer forming section 501 includes a material supply section 21, a photoconductor 22, and a light source (not shown) according to the number of types of shaped particles, and forms a material layer on the carrier 24. FIG. 5 shows a configuration in which one type of structural material and one type of support material are used, but the material supply unit 21 and the photoconductor 22 provided in the material layer forming unit 501 are provided according to the number of types of modeling materials used. , You can increase the set of light sources.

The laser light 23a emitted from the light source scans the photoconductor 22a, and the laser light 23b scans the photoconductor 22b, respectively, to form latent images on the photoconductors 22a and 22b. Specifically, a latent image of the structure portion of the slice data is formed on the photoconductor 22a, and a latent image of the support body portion of the slice data is formed on the photoconductor 22b.

The material supply unit 21a contains a group of particles including structural material particles, and the material supply unit 21b stores a group of particles including support material particles. As the particle group of the structural material and the particle group of the support material, those having an average circularity of 0.80 or more and a particle size distribution Dv / Dn larger than 1.3 and satisfying 23 or less are used.

The structural material particles are supplied from the material supply unit 21a to the photoconductor 22a, and a layer made of the structural material particles is formed on the photoconductor 22a. Further, the support material particles are supplied to the photoconductor 22b from the material supply unit 21b, and a layer made of the support material particles is formed on the photoconductor 22b. The layers formed on each of the photoconductors 22a and 22b are electrostatically transferred to the carrier 24 in order to form a material layer composed of structural material particles and support material particles according to the slice data for one layer. The order in which the material layer is transferred to the carrier 24 is not limited to this, and the layer composed of one of the structural material particles and the support material particles is transferred, and then the layer composed of the other particles is transferred. It is good to form it.

The material layer formed on the carrier 24 is heated and melted, transferred onto the modeled object under construction on the base 25, and laminated. At the time of laminating, the opposing member 26 and the stage 25 can pressurize the modeled object in the process of modeling and the heated material layer. The material layer may be heated by the facing member 26 having a built-in heater, or may be heated by a heating means different from that of the facing member 26. As a result, a modeled object composed of the structure 27a of the portion made of the structural material particles and the support body 27b of the portion made of the support material particles is formed.

The modeling apparatus suitable for the electrophotographic method is not limited to the configuration shown in FIG. It is preferable to combine the functions of the material supply unit 21 and the photoconductor 22 into a cartridge so that the modeling apparatus has a structure in which the cartridge can be exchanged because the material can be easily replenished or exchanged. The cartridge includes a photoconductor, a charging means for charging the photoconductor, an opening for irradiating the photoconductor with a laser beam, and a material accommodating portion and a material supply means corresponding to a material supply portion. It is good to have. In the material accommodating portion, a group of particles having an average circularity of 0.80 or more and a particle size distribution Dv / Dn larger than 1.3 and satisfying 23 or less according to the present invention is accommodated as a modeling material.

The modeled object is completed by laminating the number of material layers according to the slice data. After that, by removing the support body from the modeled object, a three-dimensional object that is a modeled object can be obtained. When particles made of a water-soluble thermoplastic substance are used as the support material particles, if the modeled object is immersed in a solvent containing water, the support body is dissolved in water and can be easily removed from the modeled object.

As described above, if the particle group according to the present invention is used as a modeling material for modeling, the material layer can be melted to a uniform thickness, and the voids generated during lamination can be reduced. As a result, it is possible to obtain a three-dimensional object having few voids, high strength, and excellent appearance.

11a, 11b Particles 12, 20 Voids 21a, 21b Material supply part 22a, 22b Photoreceptor 23a, 23b Exposure light source 24 Carrier 25 Base 26 Opposing member 27a Structure 27b Support 500 Modeling device 501 Material layer forming part 502 Modeling unit

Claims (14)

A group of particles used as a modeling material for additive manufacturing.
The average circularity is 0.80 or more, the volume-based average particle size is Dv, the number-based average particle size is Dn, and Dv / Dn is greater than 1.3 and 23 or less.
A particle group characterized in that the particles contained in the particle group contain a water-soluble thermoplastic substance. The particle group according to claim 1 , wherein the average circularity is 0.90 or more. The particle group according to claim 1 or 2 , wherein the Dv / Dn is greater than 1.3 and 5.0 or less. The particle group according to any one of claims 1 to 3, wherein the water-soluble thermoplastic substance is a compound having a hydroxyl group. A method for manufacturing a three-dimensional object, which includes a step of arranging a modeling material to form a material layer and a step of melting and laminating the material layer.
As the modeling material, particles having an average circularity of 0.80 or more, a volume-based average particle size of Dv, a number-based average particle size of Dn, and a Dv / Dn greater than 1.3 and 23 or less. Using a group
A method for producing a three-dimensional object, characterized in that the particles constituting the particle group contain a water-soluble thermoplastic substance. The method for producing a three-dimensional object according to claim 5 , wherein a particle group having an average circularity of 0.90 or more is used. The particle group according to claim 5 or 6 , wherein a particle group having a Dv / Dn of more than 1.3 and 5.0 or less is used as the modeling agent. The method for producing a three-dimensional object according to any one of claims 5 to 7, wherein the material layer is formed by using an electrophotographic method. The method for producing a three-dimensional object according to any one of claims 5 to 8 , wherein the material layer is melted by applying thermal energy. A method for producing a three-dimensional object including a step of arranging a modeling material to form a material layer and a step of melting and laminating the material layer, wherein a plurality of types of particle groups are used as the modeling material. For each type of particle group, the average circularity is 0.80 or more, the volume-based average particle size is Dv, and the number-based average particle size is Dn, and Dv / Dn is larger than 1.3. Is below
A method for producing a three-dimensional object, wherein the particles constituting the particle group contain a thermoplastic substance. The tenth aspect of the present invention, wherein the plurality of types of particle groups include a particle group of a structural material constituting a three-dimensional object and a particle group of a support material that supports the structural material during production. Manufacturing method of three-dimensional objects. The method for producing a three-dimensional object according to claim 11 , further comprising a step of removing a portion composed of the support material from a modeled object formed by melting and laminating the material layer. The method for producing a three-dimensional object according to claim 12 , wherein the particles constituting the particle group of the support material contain a water-soluble thermoplastic substance. The three-dimensional object according to claim 13 , wherein in the step of removing the portion composed of the support material, the portion composed of the support material is dissolved in a solvent containing water and removed from the modeled object. Manufacturing method of things.