Method and apparatus for measuring deterioration degree of powder for molding, method and apparatus for producing regenerated powder for molding, and method and apparatus for manufacturing three-dimensional molded article

Abstract

To provide a method and an apparatus for measuring a deterioration degree of powder for molding which can suppress lowering of mechanical characteristics and dimensional accuracy of a molded article, a method and an apparatus for producing regenerated powder for molding, and a method and an apparatus for manufacturing a three-dimensional molded article.SOLUTION: Spin-spin relaxation time T2 of a 1H nucleus of a dispersion element in which powder for molding is dispersed in a solvent is measured by using a pulse NMR device, and a specific surface area of the powder for molding is calculated on the basis of spin-spin relaxation time T2 of the 1H nucleus of the dispersion element and the spin-spin relaxation time T2 of a 1H nucleus of the solvent. The specific surface area of the powder for molding apparently increases / decreases depending on preheating in a powder head and heat when the powder is irradiated with a laser beam and an electron beam, and accordingly can be used as an index of a deterioration degree of the powder for molding.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present technology relates to a method and device for measuring the deterioration level of a powder for layered manufacturing by irradiation with a laser or electron beam, a method and device for manufacturing recycled powder for layered manufacturing, and a method and device for manufacturing a three-dimensional object. This application claims priority based on International Application No. PCT / JP2022 / 040669, filed on October 31, 2022, which is incorporated herein by reference. [Background technology]

[0002] Conventionally, there are known technologies for manufacturing parts and products by additive manufacturing using powders such as resin and metal. For example, the powder bed method involves laying powder in layers, irradiating it with a laser or beam to sinter or melt the powder particles, and repeating this process to create additive manufacturing. The powder bed method can increase the density of the molded object, so it is possible to obtain physical properties similar to those of conventional mass production manufacturing methods (such as injection molding for resin and casting for metal).

[0003] In additive manufacturing, a part of the powder laid out in layers is sintered or melted by a laser or the like, so it is desirable to reuse the powder that is not sintered or melted. For example, Patent Document 1 discloses classifying the powder with a sieve and reusing it. However, by simply classifying the powder, it is not possible to detect the degree of deterioration of the powder, and there is a risk that the mechanical properties and dimensional accuracy of the model may decrease. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-050671 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present technology has been proposed in consideration of the above-mentioned conventional situation, and provides a method and device for measuring the deterioration level of powder for modeling, which can suppress the deterioration of the mechanical properties and dimensional accuracy of the modeled object, a method and device for manufacturing recycled powder for modeling, and a method and device for manufacturing three-dimensional models. [Means for solving the problem]

[0006] The inventors of the present invention have investigated the properties of powder for molding using pulsed NMR. 1 It was found that the specific surface area of ​​the powder for molding determined by measuring the spin-spin relaxation time T2 of H nuclei indicates the degree of deterioration of the powder for molding. This is thought to be because the apparent specific surface area of ​​the powder for molding increases or decreases due to preheating in the powder bed and heat generated when irradiated with a laser or electron beam. Note that whether the specific surface area increases or decreases due to deterioration of the powder for molding differs depending on the type of powder for molding.

[0007] In addition, the degree of deterioration of the molding powder to be tested can be measured based on the specific surface area S1 of the powder obtained by measuring the relaxation time T21 of a reference dispersion in which a reference powder is dispersed, and the specific surface area S2 of the powder obtained by measuring the relaxation time T22 of a test dispersion in which the powder to be tested is dispersed, i.e., based on the relaxation time T21 of the reference dispersion and the relaxation time T22 of the test dispersion.

[0008] In order to solve the above problems, the present technology provides the following method and device for measuring the deterioration level of powder for modeling, method and device for manufacturing recycled powder for modeling, and method and device for manufacturing three-dimensional objects.

[0009] [1] Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was 1 The spin-spin relaxation time T21 of H nuclei is measured, and the test dispersion in which the powder for molding to be tested is dispersed in the solvent is 1 Measure the spin-spin relaxation time T22 of H nuclei, The reference dispersion 1The spin-spin relaxation time T21 of H nuclei and the 1 A method for measuring the deterioration level of a powder for shaping, comprising calculating the deterioration level of the powder for shaping to be inspected based on the spin-spin relaxation time T22 of H nuclei. [2] The method for measuring the deterioration degree of a powder for use in molding described in [1], wherein the powder for use in molding is a thermoplastic resin or a metal. [3] The Hansen solubility parameter of the solvent is 14 (J / cm 3 ) 1 / 2 More than 30(J / cm 3 ) 1 / 2 A method for measuring the deterioration degree of a powder for molding according to the following [1] or [2]. [4] Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was 1 The spin-spin relaxation time T21 of H nuclei is measured, and the test dispersion in which the powder for molding to be tested is dispersed in the solvent is 1 The spin-spin relaxation time T22 of H nuclei was measured, and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 The deterioration degree measuring device for the powder for shaping, which calculates the deterioration degree of the powder for shaping to be inspected based on the spin-spin relaxation time T22 of H nucleus. [5] The deterioration degree measuring device for a powder for use in molding described in [4], wherein the powder for use in molding is a thermoplastic resin or a metal. [6] The Hansen solubility parameter of the solvent is 14 (J / cm 3 ) 1 / 2 More than 30(J / cm 3 ) 1 / 2 The deterioration level measuring device for a powder for molding according to [4] or [5] below. [7] Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was 1 The spin-spin relaxation time T21 of H nuclei was measured, and the used modeling powder to be inspected was dispersed in the solvent to obtain a test dispersion. 1The spin-spin relaxation time T22 of H nuclei was measured, and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 A measuring step of calculating the deterioration degree of the used powder for molding based on the spin-spin relaxation time T22 of H nuclei; A generation process of mixing the used modeling powder with the unused modeling powder based on the deterioration degree of the used modeling powder to generate a recycled modeling powder; A method for producing recycled powder for molding having the above structure. [8] Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was 1 The spin-spin relaxation time T21 of H nuclei was measured, and the used modeling powder to be inspected was dispersed in the solvent to obtain a test dispersion. 1 The spin-spin relaxation time T22 of H nuclei was measured, and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 A measurement unit for calculating the deterioration degree of the used powder for molding based on the spin-spin relaxation time T22 of H nuclei; a generating unit that mixes the used powder for modeling with the unused powder for modeling based on the deterioration degree of the used powder for modeling, and generates recycled powder for modeling; A manufacturing apparatus for recycled powder for modeling comprising: [9] Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was 1 The spin-spin relaxation time T21 of H nuclei was measured, and the used modeling powder to be inspected was dispersed in the solvent to obtain a test dispersion. 1 The spin-spin relaxation time T22 of H nuclei was measured, and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 A measuring step of calculating the deterioration degree of the used powder for molding based on the spin-spin relaxation time T22 of H nuclei; A generation process of mixing the used modeling powder with the unused modeling powder based on the deterioration degree of the used modeling powder to generate a recycled modeling powder; A molding step of molding a three-dimensional object by layered manufacturing using the recycled powder for modeling; A method for manufacturing a three-dimensional object having the above structure.

[10] Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was 1 The spin-spin relaxation time T21 of H nuclei was measured, and the used modeling powder to be inspected was dispersed in the solvent to obtain a test dispersion. 1 The spin-spin relaxation time T22 of H nuclei was measured, and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 A measurement unit for calculating the deterioration degree of the used powder for molding based on the spin-spin relaxation time T22 of H nuclei; A generation unit that mixes the used modeling powder with the unused modeling powder based on the deterioration degree of the used modeling powder to generate a recycled modeling powder; a molding section that molds a three-dimensional object by layered molding using the recycled powder for molding; A manufacturing device for three-dimensional objects comprising:

[11] Using a pulsed NMR device, the dispersion of the modeling powder in the solvent was 1 The spin-spin relaxation time T2 of H nuclei was measured, and the dispersion 1 The spin-spin relaxation time T2 of the H nucleus and the 1 The deterioration degree measuring device for the powder for shaping calculates the specific surface area of ​​the powder for shaping based on the spin-spin relaxation time T2 of H nuclei.

[12] Using a pulsed NMR device, the dispersion of the modeling powder in the solvent was 1 The spin-spin relaxation time T2 of H nuclei was measured, and the dispersion 1 The spin-spin relaxation time T2 of the H nucleus and the 1 A method for measuring the deterioration degree of a powder for use in shaping, which calculates the specific surface area of ​​the powder for use in shaping based on the spin-spin relaxation time T2 of H nuclei.

[13] The method for measuring the deterioration degree of a powder for use in molding described in

[12] , wherein the powder for use in molding is a thermoplastic resin or a metal.

[14] The Hansen solubility parameter of the solvent is 14 (J / cm 3 ) 1 / 2 More than 30(J / cm 3 ) 1 / 2 A method for measuring the deterioration degree of a powder for shaping according to the following

[12] or

[13] .

[15] The solvent 1 The method for measuring the deterioration degree of a powder for molding according to

[12] or

[13] , wherein the spin-spin relaxation time T2 of the H nucleus is 1000 ms or longer.

[16] A method for measuring the degree of deterioration of a powder for use in molding described in

[12] or

[13] , in which the degree of deterioration of the powder for use in molding after use is calculated based on the specific surface area of ​​the powder for use in molding before use, which has been measured and calculated in advance.

[17] The used powder for molding was sampled, and the dispersion in which the used powder for molding was dispersed in a solvent was analyzed using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the dispersion 1 The spin-spin relaxation time T2 of the H nucleus and the 1 A measuring step of calculating a specific surface area of ​​the used powder for shaping based on the spin-spin relaxation time T2 of H nuclei; A generation process of mixing the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling to generate recycled powder for modeling; A method for producing recycled powder for molding having the above structure.

[18] The used powder for molding was sampled, and the dispersion in which the used powder for molding was dispersed in a solvent was analyzed using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the dispersion 1 The spin-spin relaxation time T2 of the H nucleus and the 1 A measuring unit for calculating a specific surface area of ​​the used powder for molding based on a spin-spin relaxation time T2 of H nuclei; a generating unit that mixes the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling, and generates recycled powder for modeling; A manufacturing apparatus for recycled powder for modeling comprising:

[19] The used powder for molding was sampled, and the dispersion in which the used powder for molding was dispersed in a solvent was analyzed using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the dispersion 1 The spin-spin relaxation time T2 of the H nucleus and the 1 A measuring step of calculating a specific surface area of ​​the used powder for shaping based on the spin-spin relaxation time T2 of H nuclei; A generation process of mixing the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling to generate recycled powder for modeling; A molding step of molding a three-dimensional object by layered manufacturing using the recycled powder for modeling; A method for manufacturing a three-dimensional object having the above structure.

[20] The used powder for molding was sampled, and the dispersion in which the used powder for molding was dispersed in a solvent was analyzed using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the dispersion 1 The spin-spin relaxation time T2 of the H nucleus and the 1 A measuring unit for calculating a specific surface area of ​​the used powder for molding based on a spin-spin relaxation time T2 of H nuclei; A generation unit that mixes the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling to generate recycled powder for modeling; a molding section that molds a three-dimensional object by layered molding using the recycled powder for molding; A manufacturing device for three-dimensional objects comprising: Effect of the Invention

[0010] According to the present technology, it is possible to detect the degree of deterioration of the powder for modeling, to regenerate the powder for modeling, and to suppress deterioration of the mechanical properties and dimensional accuracy of the modeled object. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a functional block diagram showing an example of a manufacturing apparatus for recycled powder to which the present technology is applied. [Diagram 2] FIG. 2 is a flowchart for explaining an example of the operation of a manufacturing device for recycled powder to which the present technology is applied. [Diagram 3] FIG. 3 is a cross-sectional view showing an outline of an example of a three-dimensional printing apparatus to which the present technology is applied. [Figure 4] Figure 4 is a cross-sectional view for explaining the modeling operation of a 3D modeling device, where Figure 4(A) shows the powder supply process, Figure 4(B) shows the powder layer flattening process, Figure 4(C) shows the flattening roller return process, and Figure 4(D) shows the modeling process for forming a modeled object. [Diagram 5] FIG. 5 is a graph showing the melt flow rate versus heating time for PA12. [Figure 6] FIG. 6 is a graph showing the relaxation time T2 versus heating time for PA12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present technology will be described in detail with reference to the drawings in the following order. 1. Method and device for measuring deterioration of molding powder 2. Manufacturing method and manufacturing equipment for recycled powder for modeling 3. Manufacturing method and equipment for 3D objects 4. Working Example

[0013] <1. Method and device for measuring deterioration level of powder for molding> The deterioration level measuring method and measuring device of the powder for shaping according to the present embodiment uses a pulse NMR device to measure the deterioration level of a dispersion in which the powder for shaping is dispersed in a solvent. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the 1 The spin-spin relaxation time T2 of the H nucleus and the 1The specific surface area of ​​the powder for molding is calculated based on the spin-spin relaxation time T2 of the H nucleus. The specific surface area of ​​the powder for molding increases or decreases due to preheating in the powder bed or heat generated when irradiated with a laser or electron beam, and can therefore be used as an index of the degree of deterioration of the powder for molding.

[0014] In addition, the deterioration degree measuring method and measuring device of the shaping powder according to the present embodiment uses a pulse NMR device to measure the deterioration degree of a reference dispersion in which a reference shaping powder is dispersed in a solvent. 1 The spin-spin relaxation time T21 of H nuclei was measured, and the powder for modeling to be tested was dispersed in a solvent. 1 The spin-spin relaxation time T22 of the H nucleus was measured and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 The degree of deterioration of the molding powder being inspected is measured based on the spin-spin relaxation time T22 of the H nucleus.

[0015] [Powder for modeling] The powder for molding is not particularly limited as long as it is used in a 3D printer, and examples thereof include thermoplastic resins and metals. Examples of thermoplastic resins include general-purpose resins and engineering plastics. Examples of general-purpose resins include polypropylene (PP), polyethylene (PE), polyvinyl alcohol (PVA), polyvinylidene chloride (PVDC), and polyethylene terephthalate (PET). Examples of engineering plastics include polyamides (PA) such as nylon 12 (PA12) and nylon 6 (PA6), polycarbonate (PC), polyether ether ketone (PEEK), and fluororesins such as polytetrafluoroethylene (PTFE), liquid crystal polymers (LCP), polyamideimide (PAI), and polyetherimide (PEI). Examples of metals include titanium, aluminum, stainless steel, cobalt-chromium, nickel alloys, and copper alloys.

[0016] The powder particles preferably have an average particle size of 10 μm to 200 μm inclusive. The average particle size can be determined by measuring 200 or more particles under a microscope (optical microscope, metallurgical microscope, electron microscope, etc.) and averaging the measured values.

[0017] [solvent] The solvent can be appropriately selected depending on the powder for molding, for example, based on the Hansen solubility parameter (HSP) of the solvent. The lower limit of the Hansen solubility parameter (HSP) of the solvent is preferably 5 (J / cm 3 ) 1 / 2 More preferably, 10 (J / cm 3 ) 1 / 2 More preferably, 14 (J / cm 3 ) 1 / 2 The lower limit of the HSP of the solvent is preferably 40 (J / cm 3 ) 1 / 2 Less than or equal to 35 (J / cm 3 ) 1 / 2 Less than 30 (J / cm 3 ) 1 / 2 In particular, the HSP of the solvent is 14 (J / cm 3 ) 1 / 2 More than 30(J / cm 3 ) 1 / 2 By satisfying the above condition, excellent dispersibility of the shaping powder can be obtained, and the degree of deterioration can be compared.

[0018] The Hansen solubility parameter (δ) is composed of three parameters: the dispersion term δd, the polarity term δp, and the hydrogen bonding term δh, and is expressed by the following equation (1).

[0019] δ 2 = δd 2 + δp 2 + δh 2 (1) δd: Energy due to intermolecular dispersion forces δp: Energy due to dipole interactions between molecules δh: Energy due to hydrogen bonds between molecules

[0020] For the Hansen solubility parameters (δ, δd, δp, δh), for example, the values ​​recorded in computer software Hansen Solubility Parameters in Practice 4th Edition 4.1.07 (HSPiP) can be used as is.

[0021] Specific examples of the Hansen solubility parameters (δ, δd, δp, δh) of solvents include ethanol (δ: 26.5, δd: 15.8, δp: 8.8, δh: 19.4), DPG (dipropylene glycol, SP: 26.4, δd: 16.5, δp: 10.6, δh: 17.7), butanol (δ: 23.2, δd: 16, δp: 5.7, δh: 15.8), DMAC (dimethylacetamide, SP: 22.4, δd: 16.8, δp: 11.5, δh: 9.4), ethyl lactate (δ: 21.7, δd: 16, δp: 7.6, δh: 12.5), and acetic acid. (δ:21.4, δd:14.5, δp:8, δh:13.5), cyclohexanone (SP:20.3, δd:17.8, δp:8.4, δh:5.1), acetone (δ:20, δd:15.5, δp:10.4, δh:7), toluene (δ:18.2, δd:18, δp:1.4, δh:2), MCH (methylcyclohexane, SP:16, δd:16, δd:0, δh:1), hexane (δ:14.9, δd:14.9, δp:0, δh:0), NMP (N-methyl-2-pyrrolidone, δd:18.0, δp:12.3, δh:7.2), etc.

[0022] [Specific surface area measured by pulsed NMR] Pulsed NMR (Nuclear Magnetic Resonance) is an index for evaluating molecular mobility. 1 This is a method specialized for obtaining the relaxation time (spin-lattice relaxation time T1) and spin-spin relaxation time T2 of H nuclei. 1 The spin-spin relaxation time T2 of H nucleus is called "transverse relaxation time" or simply "relaxation time T2". The transverse relaxation time can be measured, for example, using a pulsed NMR instrument Acorn area manufactured by Xigo nanotools.

[0023] The pulse sequence in the pulse NMR measurement can be appropriately selected from, for example, the Hahn echo method, the solid echo method, the CPMG method (Carr-Purcell-Meiboom-Gill method), the 90° pulse method, etc. When the influence of the diffusion of the powder for molding is expected to be large, it is preferable to apply the CPMG method. In the CPMG method, spin echoes are repeated by successive 180° pulses at regular intervals, and the magnetization is fixed on the xy plane of a rotating coordinate system. Since the sum of the transverse magnetization decreases due to the T2 relaxation during this time, the transverse relaxation time can be measured.

[0024] The specific surface area of ​​a powder determined by measuring the relaxation time T2 of a powder dispersion using pulsed NMR can be used as an index of the powder's deterioration. This is thought to be because the apparent specific surface area of ​​a powder increases or decreases due to preheating in the powder bed or heat generated when irradiated with a laser or electron beam. This makes it possible to detect the deterioration of the powder and regenerate it.

[0025] The specific surface area is the surface area per unit mass of a powder, and the finer the particles, the larger it is for the same mass. The specific surface area can be calculated from the relaxation time T2 in pulse NMR measurement using the following formula (2). R av =Ψ p SLρ p (R s -R b )+R b (2) R av : Average relaxation rate of the dispersion (reciprocal of relaxation time) Psi p : Ratio of particle volume to solvent volume S: Surface area per unit mass (specific surface area) L: Thickness of the solvent bound to the particle surface ρ p :Particle density R s : Relaxation rate of the solvent bound to the particle interface (reciprocal of relaxation time) R b: Relaxation rate of the solvent in a free (bulk) state (reciprocal of relaxation time)

[0026] Here, when Ka is defined by the following formula (3), the specific surface area S is expressed by the following formula (4). Ka = Lρ p (R s -R b ) (3)

[0027] S=(R av -R b ) / KaΨ p (4) Ka can be calculated using the specific surface area that is actually in contact with the solvent. For example, in the case of silica, the area that is actually in contact with the liquid can be obtained by using the Sears method. Alternatively, it may be calculated from particle size measurements using dynamic light scattering, centrifugal sedimentation, laser diffraction, or a microscope.

[0028] Also, Ψ p can be calculated by the following formula (5).

[0029] Psi p =(S c / S d ) / [(1-S c ) / T d ] (5) In the formula, S c is the solids concentration of the powder in the dispersion (mass%), S d is the powder density (g / cm 3 ), T d is the density of the solvent (g / cm 3 ) is shown.

[0030] That is, the relaxation time T2 (R b If the relaxation time T2 (R av The specific surface area S can be calculated from the

[0031] In addition, the ratio between the specific surface area S1 of a powder obtained by measuring the relaxation time T21 of a reference dispersion in which a reference powder is dispersed, and the specific surface area S2 of a powder obtained by measuring the relaxation time T22 of a test dispersion in which a powder to be tested is dispersed, can be calculated by the following formula (6). S2 / S1=(R av2 -R b ) / (R av1 -R b ) (6)

[0032] In other words, the deterioration degree of the molding powder to be inspected can be measured based on the relaxation time T21 of the reference dispersion and the relaxation time T22 of the test dispersion, and for example, the deterioration degree can be calculated by the ratio of the relaxation time T21 of the reference dispersion to the relaxation time T22 of the test dispersion. Specifically, the deterioration degree may be calculated as the ratio (T22 / T21) of the relaxation time T22 of the test dispersion to the relaxation time T21 of the reference dispersion, or (R av2 -R b ) / (R av1 -R b ), R av2 / R av1 (=T21 / T22) may also be calculated.

[0033] In general, the motion of liquid molecules adsorbed on particle surfaces is restricted, whereas liquid molecules in the bulk liquid can move freely. As a result, the transverse relaxation time of liquid molecules adsorbed on particle surfaces is shorter than that of liquid molecules in the bulk liquid.

[0034] The larger the volume fraction Ps of the dispersion medium adsorbed on the particle surface, the shorter the transverse relaxation time. Therefore, the larger the total surface area of ​​the particle, the shorter the transverse relaxation time. Therefore, the larger the specific surface area of ​​the particle, the shorter the transverse relaxation time, and the smaller the particle diameter, the shorter the transverse relaxation time tends to be. Also, the more particles there are, the shorter the transverse relaxation time tends to be.

[0035] Moreover, the stronger the interaction between the particles and the dispersion medium, the shorter the transverse relaxation time. In other words, the higher the affinity between the particles and the dispersion medium, the shorter the transverse relaxation time. The affinity between the particles and the dispersion medium can be adjusted, for example, by the type and number of functional groups on the particle surface and the compound added to the dispersion medium.

[0036] The lower limit of the transverse relaxation time of the dispersion medium measured using a pulsed NMR device is preferably 50 ms or more, more preferably 500 ms or more, and even more preferably 1000 ms or more. The upper limit of the transverse relaxation time of the dispersion medium measured using a pulsed NMR device is preferably 5000 ms or less, more preferably 3000 ms or less, and even more preferably 2500 ms or less. This makes it possible to increase the ratio of the specific surface area of ​​the powder to the specific surface area of ​​the solvent.

[0037] <2. Manufacturing method and manufacturing device for recycled powder for molding> The manufacturing method of the recycled powder for shaping according to the present embodiment involves sampling the powder for shaping after use, and measuring the dispersion of the powder for shaping after use in a solvent using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the 1 The spin-spin relaxation time T2 of the H nucleus and the 1 The method includes a measurement step of calculating the specific surface area of ​​the used powder for molding based on the spin-spin relaxation time T2 of the H nucleus, and a production step of mixing the used powder for molding with the powder for molding before use based on the specific surface area of ​​the used powder for molding to produce recycled powder for molding.

[0038] In addition, the manufacturing method of the regenerated powder for molding according to the present embodiment uses a pulse NMR device to measure the molecular weight of a reference dispersion in which a reference powder for molding is dispersed in a solvent. 1 The spin-spin relaxation time T21 of H nuclei was measured, and the used modeling powder to be tested was dispersed in a solvent. 1 The spin-spin relaxation time T22 of the H nucleus was measured and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1The method includes a measurement process for calculating the degree of deterioration of the used modeling powder based on the spin-spin relaxation time T22 of the H nucleus, and a production process for mixing the used modeling powder with the unused modeling powder based on the degree of deterioration of the used modeling powder to produce recycled modeling powder.

[0039] The manufacturing device for recycled powder for shaping according to the present embodiment samples used powder for shaping, and measures the dispersion of the used powder for shaping in a solvent using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the 1 The spin-spin relaxation time T2 of the H nucleus and the 1 The apparatus is equipped with a measuring unit that calculates the specific surface area of ​​the used powder for modeling based on the spin-spin relaxation time T2 of the H nucleus, and a generating unit that mixes the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling to generate recycled powder for modeling.

[0040] In addition, the manufacturing apparatus for the regenerated powder for shaping according to the present embodiment uses a pulse NMR device to measure the concentration of the standard dispersion in which the standard powder for shaping is dispersed in a solvent. 1 The spin-spin relaxation time T21 of H nuclei was measured, and the used modeling powder to be tested was dispersed in a solvent. 1 The spin-spin relaxation time T22 of the H nucleus was measured and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 The apparatus includes a measurement unit that calculates the degree of deterioration of the used modeling powder based on the spin-spin relaxation time T22 of the H nucleus, and a generation unit that mixes the used modeling powder with the unused modeling powder based on the degree of deterioration of the used modeling powder to generate recycled modeling powder.

[0041] According to such an embodiment, for example, the deterioration degree of the used molding powder is calculated based on the specific surface area of ​​the molding powder before use that is measured and calculated in advance, and the deterioration degree of the used molding powder is calculated based on the relaxation time T21 of the reference powder and the relaxation time T22 of the used powder to be inspected, thereby calculating the mixing ratio of the used molding powder and the molding powder before use, and also calculating the deterioration degree of the mixed molding powder. This makes it possible to manufacture recycled molding powder having a predetermined deterioration degree (specific surface area).

[0042] [Regenerated powder manufacturing equipment] FIG. 1 is a functional block diagram showing an example of a manufacturing apparatus for recycled powder to which the present technology is applied. As shown in FIG. 1, the recycled powder manufacturing apparatus 10 includes a powder recovery section 11 for recovering used powder, a sieve mesh classification section 12 for sieving the powder, a measurement section 13 for measuring the deterioration degree of the powder, a powder supply section 14 for supplying new powder, a mixing section 15 for mixing the powder that has passed through the sieve mesh with the new powder, an output section 16 for outputting the recycled powder, and a control section 17 for controlling the amount of new powder supplied from the powder supply section 14 to the mixing section 15. Note that, when using a powder that has not been preheated in a powder bed or has not been affected by heat from a laser or an electron beam as the used powder, the sieve classification section 12 may not be provided.

[0043] The powder recovery unit 11 recovers, for example, powder used in the 3D modeling apparatus 20 described later. For example, the powder recovery unit 11 may recover powder 41 from a modeling tank 40 that was not used to form an object in the 3D modeling apparatus 20 described later, or may recover powder 51 from a recovery tank 50. Examples of a powder transport method for recovery include a screw conveyor method using a screw and a pneumatic transport method using air.

[0044] The sieve mesh classification unit 12 classifies the used powder collected in the powder recovery unit 11 using a sieve mesh. This separates the used powder into fine powder consisting of fine particles that pass through the sieve mesh and coarse powder consisting of coarse particles that remain on the sieve mesh. The coarse powder may be discarded, or may be pulverized in a ball mill or the like and the fine particles may be extracted by air flow classification and returned to the powder recovery unit 11.

[0045] The measuring unit 13 samples a part of the powder that has passed through the sieve and measures the deterioration degree of the powder. 1 The spin-spin relaxation time T2 of H nuclei is measured, and the specific surface area of ​​the powder is calculated. The calculation result of the specific surface area is transmitted to the control unit 17. The measurement unit 13 may also sample the mixed powder in the mixer 15, calculate the specific surface area of ​​the mixed powder using a pulse NMR device, and transmit the calculation result to the control unit 17.

[0046] The powder supplying unit 14 stores new powder and supplies a predetermined amount of new powder notified by the control unit 17 to the mixing unit 15. The mixing unit 15 mixes the powder that has passed through the sieve mesh of the sieve mesh classifying unit 12 with the new powder supplied from the powder supplying unit 14. The output unit 16 outputs the powder mixed in the mixing unit 15 as usable recycled powder. For example, the output unit 16 outputs the recycled powder to a powder tank 30 of the 3D modeling device 20 described later.

[0047] The control unit 17 controls the processing of each unit. Specifically, the control unit 17 controls the supply amount of new powder supplied from the powder supply unit 14 to the mixing unit 15 based on the specific surface area calculated by the measurement unit 13. The control unit 17 may determine a first supply amount of new powder based on the specific surface area of ​​the powder that passed through a sieve mesh, and may determine a second supply amount of new powder based on the specific surface area of ​​the powder after mixing. The control unit 17 also controls the amount of used powder supplied to the sieve mesh classification unit 12, etc.

[0048] [Operation of recycled powder manufacturing equipment] Next, the operation of the manufacturing apparatus for recycled powder will be described with reference to Figures 1 and 2. Figure 2 is a flowchart for explaining an example of the operation of the manufacturing apparatus for recycled powder to which the present technology is applied.

[0049] As shown in FIG. 2, first, in step S1, the powder recovery unit 11 recovers, for example, powder 41 in the modeling tank 40 and powder 51 in the recovery tank 50 that have not been formed into an object by the 3D modeling apparatus 20 described later.

[0050] In step S2, the sieve mesh classification unit 12 classifies the used powder collected in the powder recovery unit 11 using a sieve mesh. This separates the used powder into fine powder consisting of fine particles that pass through the sieve mesh and coarse powder consisting of coarse particles that remain on the sieve mesh. The coarse powder may be discarded, or may be pulverized in a ball mill or the like and the fine particles may be extracted by air flow classification and returned to the powder recovery unit 11.

[0051] In step S3, the measurement unit 13 samples a portion of the fine powder that passed through the sieve in step S2, and measures the dispersion of the used powder in the solvent using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei is measured, and the specific surface area of ​​the powder after use is calculated. The control unit 17 calculates the first supply amount of new powder to be supplied from the powder supply unit 14 to the mixing unit 15 based on the specific surface area of ​​the powder after use.

[0052] In step S4, the powder supply unit 14 supplies the first supply amount of new powder calculated by the control unit 17 to the mixer 15, and the mixer 15 mixes the powder that has passed through the sieve mesh of the sieve mesh classifier 12 with the new powder supplied from the powder supply unit 14. The measurement unit 13 may also sample a portion of the mixed powder in the mixer 15 and calculate the specific surface area of ​​the mixed powder using a pulsed NMR device, and the control unit 17 may calculate a second supply amount of new powder based on the specific surface area of ​​the mixed powder and cause the powder supply unit 14 to supply the new powder to the mixer 15. The output unit 16 outputs the powder mixed in the mixer 15, for example, to a powder tank 30 of the three-dimensional modeling device 20 described later, as usable recycled powder.

[0053] As described above, by mixing used powder with new powder based on the specific surface area of ​​the used powder calculated using a pulse NMR device, a recycled powder having a predetermined specific surface area can be produced.

[0054] In the above-mentioned manufacturing device for recycled powder, the measurement unit 13 calculates the specific surface area of ​​the powder, and the control unit 17 controls the supply amount of new powder based on the specific surface area, but this is not limited to the above. For example, the deterioration degree of the used shaping powder may be calculated based on the relaxation time T21 of the reference powder and the relaxation time T22 of the used powder to be inspected, and the control unit 17 may control the supply amount of new powder based on the deterioration degree of the used shaping powder.

[0055] <3. Manufacturing method and manufacturing equipment for 3D objects> The method for producing a three-dimensional object according to the present embodiment involves sampling the used modeling powder, dispersing the used modeling powder in a solvent, and measuring the dispersion using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the 1 The spin-spin relaxation time T2 of the H nucleus and the 1The method includes a measuring step of calculating the specific surface area of ​​the used modeling powder based on the spin-spin relaxation time T2 of the H nucleus, a production step of mixing the used modeling powder with the unused modeling powder based on the specific surface area of ​​the used modeling powder to produce recycled modeling powder, and a molding step of using the recycled modeling powder to mold a three-dimensional object by additive manufacturing.

[0056] In addition, the method for producing a three-dimensional object according to the present embodiment uses a pulse NMR device to measure the density of a reference dispersion in which a reference powder for modeling is dispersed in a solvent. 1 The spin-spin relaxation time T21 of H nuclei was measured, and the used modeling powder to be tested was dispersed in a solvent. 1 The spin-spin relaxation time T22 of the H nucleus was measured and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 The method includes a measurement step of calculating the degree of deterioration of the used modeling powder based on the spin-spin relaxation time T22 of the H nucleus, a production step of mixing the used modeling powder with the unused modeling powder based on the degree of deterioration of the used modeling powder to produce recycled modeling powder, and a molding step of using the recycled modeling powder to mold a three-dimensional object by additive manufacturing.

[0057] The manufacturing apparatus for a three-dimensional object according to the present embodiment samples the used modeling powder, and analyzes the dispersion of the used modeling powder dispersed in a solvent using a pulse NMR device. 1 The spin-spin relaxation time T2 of H nuclei was measured, and the 1 The spin-spin relaxation time T2 of the H nucleus and the 1 The system is equipped with a measuring unit that calculates the specific surface area of ​​the used modeling powder based on the spin-spin relaxation time T2 of the H nucleus, a generating unit that mixes the used modeling powder with the unused modeling powder based on the specific surface area of ​​the used modeling powder to generate recycled modeling powder, and a molding unit that uses the recycled modeling powder to mold a three-dimensional object by additive manufacturing.

[0058] In addition, the manufacturing apparatus for a three-dimensional object according to the present embodiment uses a pulse NMR device to measure the density of a reference dispersion in which a reference powder for modeling is dispersed in a solvent. 1 The spin-spin relaxation time T21 of H nuclei was measured, and the used modeling powder to be tested was dispersed in a solvent. 1 The spin-spin relaxation time T22 of the H nucleus was measured and the standard dispersion 1 The spin-spin relaxation time T21 of H nuclei and the 1 The system includes a measuring unit that calculates the degree of deterioration of the used modeling powder based on the spin-spin relaxation time T22 of the H nucleus, a generating unit that mixes the used modeling powder with the unused modeling powder based on the degree of deterioration of the used modeling powder to generate recycled modeling powder, and a molding unit that uses the recycled modeling powder to mold a three-dimensional object by additive manufacturing.

[0059] According to this embodiment, a three-dimensional object is additively manufactured using recycled powder for modeling having a predetermined degree of deterioration (specific surface area), thereby suppressing deterioration in the mechanical properties and dimensional accuracy of the object due to powder deterioration.

[0060] The additive manufacturing methods used in 3D modeling devices include selective laser sintering (SLS), selective laser melting (SLM), electron beam melting (EBM), etc. In general, when the powder used for modeling is resin, SLS is used, and when the powder used for modeling is metal, SLS, SLM, or EBM are used.

[0061] Below, we will explain a powder bed type 3D modeling device in which the powder for modeling is spread in a thin layer on a tray called a powder bed, and a laser or electron beam is scanned over the powder to form the cross-sectional shape of the object.

[0062] [3D printing equipment] Fig. 3 is a cross-sectional view showing an example of a schematic of a three-dimensional printing apparatus to which the present technology is applied. Fig. 4 is a cross-sectional view for explaining a printing operation of the three-dimensional printing apparatus, in which Fig. 4(A) shows a powder supply process, Fig. 4(B) shows a powder layer flattening process, Fig. 4(C) shows a flattening roller return process, and Fig. 4(D) shows a printing process for forming a model.

[0063] The three-dimensional modeling apparatus 20 includes a powder tank 30 for supplying powder, a modeling tank 40 for modeling a modeled object, and a recovery tank 50 for recovering the powder. The three-dimensional modeling apparatus 20 also includes a modeling unit 70 for emitting a laser beam 71 to form a modeling layer 60 in a powder layer 61 and forming a three-dimensional model by stacking the modeling layers 60. The three-dimensional modeling apparatus 20 also includes the above-mentioned recycled powder manufacturing apparatus 10, and may supply recycled powder output from the output unit 16 to the powder tank 30, or may supply powder 41 from the modeling tank 40 that was not used to form a modeled object to the powder recovery unit 11, or may supply powder 51 from the recovery tank 50 to the powder recovery unit 11. Examples of powder transport methods for supplying powder include a screw conveyor method using a screw and an air transport method using air.

[0064] The flattening roller 21 is a flattening means (recoater) that moves reciprocally relative to the upper surface of the modeling tank 40, transfers and supplies the powder 31 in the powder tank 30 to the modeling tank 40, flattens the powder 41 in the modeling tank 40 to form a powder layer 61, and collects the powder 51 in the collection tank 50. Note that instead of the flattening roller 21, a flattening means such as a plate-shaped member (blade) may be used.

[0065] The powder tank 30 has a box-like shape with an open top for holding the powder 31 to be supplied to the modeling tank 40, and is provided with a supply stage 32 at the bottom. The supply stage 32 moves up and down in the vertical direction (height direction), and by raising it in the direction of the arrow Z1, the powder 31 on the upper surface is transferred and supplied by the flattening roller 21. Here, the powder 31 may be the recycled powder output from the output unit 16 of the above-mentioned recycled powder manufacturing apparatus 10.

[0066] The modeling tank 40 has a box-like shape with an open top that holds the powder 41 that forms a model, and includes a modeling stage 42 at the bottom. The modeling stage 42 moves up and down in the vertical direction (height direction), and is lowered by Δt1 in the direction of the arrow Z2 to form a powder layer 61 on the top surface. The modeling tank 40 also forms modeling layers 60 in the powder layer 61 by emitting laser light 71 from the modeling unit 70, and forms a three-dimensional model by stacking the modeling layers 60. The powder 41 in the modeling tank 40 that is not used to form a model may be collected in the powder collection section 11 of the recycled powder manufacturing apparatus 10 described above as used powder.

[0067] The recovery tank 50 stores surplus powder 51 that does not form the powder layer 61, among the powder 31 transferred and supplied by the flattening roller 21 when the powder layer 61 is formed on the upper surface of the modeling tank 40. The powder 51 in the recovery tank 50 may be collected in the powder collection section 11 of the recycled powder manufacturing apparatus 10 described above as used powder.

[0068] The modeling unit 70 emits laser light 71 to the powder layer 61 on the modeling stage 42, and the entire modeling unit 70 moves reciprocally in the Y direction perpendicular to the X direction.

[0069] [Modeling operation] Next, the modeling operation of the 3D modeling device will be described with reference to Fig. 3 and Fig. 4. Here, the description will start from a state in which a first modeling layer 60 is formed on the modeling stage 42 of the modeling tank 40, as shown in Fig. 3 and Fig. 4(A).

[0070] As shown in Fig. 3 and Fig. 4(A), when forming the second modeling layer 60, the supply stage 32 of the supply tank 30 is raised in the Z1 direction, and the modeling stage 42 of the modeling tank 40 is lowered in the Z2 direction. At this time, the lowering distance of the modeling stage 42 is set so that the distance between the surface of the powder layer of the first layer and the lower part (lower tangent part) of the flattening roller 21 is Δt1. This distance Δt1 corresponds to the thickness (layer pitch) of the second powder layer 61. The distance Δt1 is preferably about 1 to 100 µm.

[0071] Next, as shown in Figure 4 (B), the powder 31 located on the upper surface of the supply tank 30 is moved in the Y1 direction (towards the modeling tank 40) while rotating the flattening roller 21, thereby transporting and supplying the powder 31 to the modeling tank 40 (powder supply process).

[0072] Furthermore, as shown in Fig. 4(B), the flattening roller 21 is moved parallel to the stage surface of the modeling stage 42 of the modeling tank 40 to flatten the powder 41 while supplying it to the modeling tank 40 (flattening process). As a result, as shown in Fig. 4(C), a powder layer 61 having a predetermined thickness Δt1 is formed on the modeling stage 42 of the modeling tank 40. At this time, surplus powder 51 not used in forming the powder layer 61 falls into the recovery tank 50.

[0073] After the powder layer 61 is formed, the flattening roller 21 is transported in the Y2 direction as shown in FIG. 4(C) and returned to the initial position (origin position) (return process).

[0074] 4(D), a laser beam 71 is emitted from the modeling unit 70 to form a modeling layer 60 in the powder layer 61 (modeling process). The modeling layer 60 is formed, for example, by the laser beam 71 generating heat in the powder layer 61 and sintering or melting the powder.

[0075] Thereafter, the above-mentioned powder supplying process, flattening process, return process, and modeling process are repeated the required number of times to manufacture a three-dimensional object having stacked modeling layers 60. Here, after the completion of the three-dimensional object, the powder 41 remaining in the modeling tank 40 and the powder 51 collected in the collection tank 50 are supplied to the powder collection unit 11 of the recycled powder manufacturing device 10, and the recycled powder output from the output unit 16 is supplied to the supply tank 30, thereby suppressing deterioration of the mechanical properties and dimensional accuracy of the object due to powder deterioration. EXAMPLES

[0076] <4. Examples> In this example, the powder for molding was dispersed in various solvents, and the specific surface area of ​​the powder for molding was calculated using a pulse NMR device.

[0077] The following powders were prepared for molding: PA12 (Nylon 12 (polyamide), average particle size 60 μm) New (unused modeling powder for 3D modeling equipment) Used items (used modeling powder used in 3D modeling equipment) Recycled products (mixture of new and used products, new:used = 20:80 (mass ratio)) PP (polypropylene, average particle size 51 μm) New (unused modeling powder for 3D modeling equipment) Used items (used modeling powder used in 3D modeling equipment) Recycled products (mixture of new and used products, new:used = 20:80 (mass ratio)) Titanium (average grain size 10~85μm) New (unused modeling powder for 3D modeling equipment) Used items (used modeling powder used in 3D modeling equipment)

[0078] The following solvents were prepared: Ethanol (δ:26.5, δd:15.8, δp:8.8, δh:19.4) DPG (dipropylene glycol, SP: 26.4, δd: 16.5, δp: 10.6, δh: 17.7) Butanol (δ:23.2, δd:16, δp:5.7, δh:15.8) DMAC (Dimethylacetamide, SP: 22.4, δd: 16.8, δp: 11.5, δh: 9.4) Ethyl lactate (δ:21.7, δd:16, δp:7.6, δh:12.5) Acetic acid (δ:21.4, δd:14.5, δp:8, δh:13.5) Cyclohexanone (SP: 20.3, δd: 17.8, δp: 8.4, δh: 5.1) Acetone (δ:20, δd:15.5, δp:10.4, δh:7) Toluene (δ:18.2, δd:18, δp:1.4, δh:2) MCH (Methylcyclohexane, SP: 16, δd: 16, δd: 0, δh: 1) Hexane (δ:14.9, δd:14.9, δp:0, δh:0)

[0079] [Pulsed NMR measurements] Using a pulse NMR device (Xigo nanotools Acorn area), the dispersion of the modeling powder in the solvent was 1 The spin-spin relaxation time T2 of H nuclei was measured, and the 1 The spin-spin relaxation time T2 of the H nucleus and the 1 The specific surface area of ​​the powder for molding was calculated based on the spin-spin relaxation time T2 of H nuclei. The specific surface area was calculated using the above-mentioned formula (4) below. S=(R av -R b ) / KaΨ p (4) R av : Average relaxation rate of the dispersion (reciprocal of the relaxation time T2 of the dispersion) Psi p : Ratio of particle volume to solvent volume S: Surface area per unit mass (specific surface area) R b : Relaxation rate of the solvent in a free state (bulk state) (the reciprocal of the relaxation time T2 of the solvent) In this example, the specific surface area was evaluated as a relative value between a new product and a used product, so the Ka value in calculating the specific surface area was set to a constant value of 0.000312, and the Ψp value was set to a constant value of 1 (solvent volume = particle volume).

[0080] The measurements using a pulsed NMR device were carried out under the following conditions. Pulse sequence: CPMG method Resonance frequency: 13MHz Bulk Relaxation Time:2600.0ms Specific Surface Relaxivity:0.000264 g / m 2 / ms Measurement temperature: 25℃ Measurement sample size: 1.0cm 3 Time from mixing to measurement: 3 min

[0081] In this example, the specific surface area of ​​the solvent was calculated using the following formula (4-1), and the specific surface area of ​​the dispersion was calculated using the following formula (4-2). SA(solvent) = (1 / T2(solvent) - 1 / 2600) / 0.000312 (4-1) SA(dispersion)=(1 / T2(dispersion)-1 / T2(solvent)) / 0.000312 (4-2) SA: Specific surface area T2: spin-spin relaxation time T2 of 1H nucleus [ms]

[0082] [Measurement example 1] Dispersions were prepared using PA12 (new, used, and recycled) as the powder for molding and ethanol as the solvent. The relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0083] [Measurement example 2] Dispersions were prepared using PA12 (new, used, and recycled) as the powder for molding and DPG (dipropylene glycol) as the solvent.Then, the relaxation time T2 of the solvent and the dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0084] [Measurement example 3] Dispersions were prepared using PA12 (new, used, and recycled) as the powder for molding and butanol as the solvent. The relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0085] [Measurement example 4] Dispersions were prepared using PA12 (new, used, and recycled) as the powder for molding and DMAC (dimethylacetamide) as the solvent. The relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0086] [Measurement example 5] A dispersion was prepared using PA12 (new and used) as the powder for molding and acetic acid as the solvent.Then, the relaxation time T2 of the solvent and the dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0087] [Measurement example 6] Dispersions were prepared using PA12 (new, used, and recycled) as the powder for molding and cyclohexane as the solvent.Then, the relaxation time T2 of the solvent and the dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0088] [Measurement example 7] A dispersion was prepared using PA12 (new and used) as the powder for molding and acetone as the solvent.Then, the relaxation time T2 of the solvent and the dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0089] [Measurement example 8] A dispersion was prepared using PA12 (new and used) as the powder for molding and toluene as the solvent.Then, the relaxation time T2 of the solvent and the dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0090] [Measurement example 9] Dispersions were prepared using PA12 (new, used, and recycled) as the powder for molding and MCH (methylcyclohexane) as the solvent. The relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0091] [Measurement example 10] A dispersion was prepared using PA12 (new and used) as the powder for molding and hexane as the solvent.Then, the relaxation time T2 of the solvent and the dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0092] [Measurement example 11] Dispersions were prepared using PP (new, used, recycled) as the powder for molding and DPG (dipropylene glycol) as the solvent.Then, the relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0093] [Measurement example 12] Dispersions were prepared using PP (new, used, and recycled) as the powder for molding and DMAC (dimethylacetamide) as the solvent. The relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0094] [Measurement example 13] Dispersions were prepared using PP (new, used, and recycled) as the powder for molding and ethyl lactate as the solvent.Then, the relaxation time T2 of the solvent and the dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0095] [Measurement example 14] Dispersions were prepared using PP (new, used, and recycled) as the powder for molding and cyclohexanone as the solvent. The relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0096] [Measurement example 15] Dispersions were prepared using PP (new, used, and recycled) as the powder for molding and MCH (methylcyclohexane) as the solvent.Then, the relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0097] [Measurement example 16] Dispersions were prepared using PP (new, used, and recycled) as the powder for molding and hexane as the solvent.Then, the relaxation time T2 of the solvent and the dispersion was measured using a pulse NMR device, and the specific surface area was calculated.

[0098] [Measurement example 17] A dispersion was prepared using titanium (new and used) as the powder for molding and DPG (dipropylene glycol) as the solvent. The relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device, and the specific surface area was calculated. The titanium used was sieved 10 times before measurement.

[0099] Table 1 shows the results of pulse NMR measurements for Measurement Examples 1 to 17. In Table 1, T2 is 1 is the spin-spin relaxation time T2 of H nuclei, SA is the specific surface area, the solvent ratio is the ratio of the solvent to the SA, and the fresh ratio is the ratio of the fresh powder to the SA.

[0100] [Table 1]

[0101] As shown in Table 1, the specific surface area of ​​the powder for molding (new, used, and recycled) can be calculated using a pulse NMR device, and it was found that this can be used as an index of the deterioration degree of the powder for molding. The solvent has a Hansen solubility parameter of 14 (J / cm 3 ) 1 / 2 More than 30(J / cm 3 ) 1 / 2 It was found that the following various materials can be used. It was also found that by setting the relaxation time T2 of the solvent to 1000 ms or more, it is possible to increase the ratio of the specific surface area of ​​the powder to the specific surface area of ​​the solvent.

[0102] In addition, it was found that the specific surface area of ​​PA12 and titanium decreased due to powder deterioration, but that the specific surface area of ​​PP increased due to powder deterioration. It was also found that it is preferable to calculate the degree of deterioration of the molding powder after use (used product) and recycled product by using the specific surface area of ​​the molding powder before use (new product) that was measured and calculated in advance as the standard (e.g. 100%).

[0103] In addition, the following modeling powder was dispersed in a solvent, and the relaxation time T2 [ms] of the modeling powder was measured using a pulse NMR device, and the ratio (T21 / T22, T22 / T21) between the relaxation time T21 of the reference modeling powder and the relaxation time T22 of the modeling powder to be tested was calculated.

[0104] The following powders were prepared for molding: PA12 (Nylon 12 (polyamide), average particle size 60 μm) New (unused modeling powder for 3D modeling equipment) Used items (used modeling powder used in 3D modeling equipment) PA11 (Nylon 11 (polyamide), average particle size 60 μm) New (unused modeling powder for 3D modeling equipment) Used items (used modeling powder used in 3D modeling equipment) PA6 (Nylon 6 (polyamide), average particle size 50 μm) Recycled products (mixture of new and used products, new:used = 20:80 (mass ratio)) Used items (used modeling powder used in 3D modeling equipment) PPS (polyphenylene sulfide, average particle size 50 μm) New (unused modeling powder for 3D modeling equipment) Used items (used modeling powder used in 3D modeling equipment) Titanium (average grain size 10~85μm) New (unused modeling powder for 3D modeling equipment) Used items (used modeling powder used in 3D modeling equipment)

[0105] The following solvents were prepared: NMP (N-methyl-2-pyrrolidone, δd: 18.0, δp: 12.3, δh: 7.2)

[0106] [Measurement example 18] Dispersion A (new) and Dispersion B (used) were prepared using PA12 (new and used) as the powder for molding and NMP (N-methyl 2-pyrrolidone) as the solvent. The relaxation times T2 of Dispersion A (new) and Dispersion B (used) were measured using a pulse NMR device, and the ratio was calculated.

[0107] [Measurement Example 19] Dispersion A (new) and Dispersion B (used) were prepared using PA11 (new and used) as the powder for molding and NMP (N-methyl 2-pyrrolidone) as the solvent. The relaxation times T2 of Dispersion A (new) and Dispersion B (used) were measured using a pulse NMR device, and the ratio was calculated.

[0108] [Measurement example 20] Dispersion A (recycled product) and Dispersion B (used product) were prepared using PA6 (recycled product, used product) as the powder for molding and NMP (N-methyl 2-pyrrolidone) as the solvent.Then, using a pulse NMR device, the relaxation times T2 of Dispersion A (recycled product) and Dispersion B (used product) were measured and the ratio was calculated.

[0109] [Measurement Example 21] Dispersion A (new) and Dispersion B (used) were prepared using PPS (new and used) as the powder for molding and NMP (N-methyl 2-pyrrolidone) as the solvent. The relaxation times T2 of Dispersion A (new) and Dispersion B (used) were measured using a pulse NMR device, and the ratio was calculated.

[0110] [Measurement example 22] Dispersion A (new) and Dispersion B (used) were prepared using titanium (new and used) as the powder for molding and NMP (N-methyl 2-pyrrolidone) as the solvent. The relaxation time T2 of the solvent and dispersion was measured using a pulse NMR device. The titanium used was sieved 10 times before measurement.

[0111] [Measurement example 23] Dispersion A (new) and Dispersion B (used) were prepared using PA12 (new and used) as the powder for molding and a mixed solvent of NMP (N-methyl 2-pyrrolidone):ethyl lactate = 9:1 as the solvent. The relaxation times T2 of Dispersion A (new) and Dispersion B (used) were measured using a pulse NMR device, and the ratio was calculated.

[0112] Table 2 shows the pulse NMR measurement results of Measurement Examples 18 to 23. In Table 1, T2A is the dispersion A 1 is the spin-spin relaxation time T2 [ms] of H nuclei, and T2B is the 1 is the spin-spin relaxation time T2 [ms] of H nucleus.

[0113] [Table 2]

[0114] As in Measurement Examples 18 to 23, even when NMP (N-methyl 2-pyrrolidone) was used as the solvent, the relaxation time T2 of the standard dispersion A and the test dispersion B could be measured, and the deterioration degree of the test modeling powder could be calculated. Also, as in Measurement Example 23, even when a mixed solvent of NMP and ethyl lactate was used, the relaxation time T2 of the standard dispersion A and the test dispersion B could be measured, and the deterioration degree of the test modeling powder could be calculated.

[0115] [Correlation with other measurement methods] FIG. 5 is a graph showing the melt flow rate versus heating time of PA12, and FIG. 6 is a graph showing the relaxation time T2 (NMP) versus heating time of PA12. PA12 powder was heated at 175°C, and the melt flow rate and relaxation time T2 (NMP) were measured for samples after a certain time. In the melt flow rate measurement, the melt flow rate decreased with heating time, and in the relaxation time T2 measurement, the relaxation time T2 increased with heating time. As can be seen by comparing the graphs shown in FIG. 5 and FIG. 6, the relaxation time T2 measurement is highly correlated with the melt flow rate measurement. The thermal degradation of PA12 powder is believed to be due to an increase in molecular weight inside the powder and denaturation of the powder surface. [Explanation of symbols]

[0116] 10 Regenerated powder manufacturing device, 11 Powder recovery section, 12 Sieve mesh classification section, 13 Measurement section, 14 Powder supply section, 15 Mixing section, 16 Output section, 17 Control section, 20 3D modeling device, 21 Flattening roller, 30 Powder tank, 31 Powder, 40 Modeling tank, 41 Powder, 50 Recovery tank, 51 Powder

Claims

1. Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was measured. １ Spin-spin relaxation time T2 of H nucleus １ The powder to be inspected is dispersed in the solvent, and the inspection dispersion is measured. １ Spin-spin relaxation time T2 of H nucleus ２ Measure The reference dispersion １ Spin-spin relaxation time T2 of H nucleus １ and the test dispersion １ Spin-spin relaxation time T2 of H nucleus ２ The deterioration degree measuring method of the powder for shaping, which calculates the deterioration degree of the powder for shaping to be inspected based on the deterioration degree of the powder for shaping.

2. The deterioration degree measuring method for a powder for shaping according to claim 1, wherein the powder for shaping is a thermoplastic resin or a metal.

3. The Hansen solubility parameter of the solvent is 14 (J / cm ３ ) １／２ More than 30 (J / cm ３ ) １／２ The method for measuring the deterioration degree of a powder for shaping according to claim 1 or 2, wherein the deterioration degree is as follows:

4. Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was measured. １ H nucleus spin-spin relaxation time T2 １ The powder to be inspected is dispersed in the solvent, and the inspection dispersion is measured. １ H nucleus spin-spin relaxation time T2 ２ The standard dispersion is measured. １ H nucleus spin-spin relaxation time T2 １ and the test dispersion １ H nucleus spin-spin relaxation time T2 ２ The deterioration level measuring device for the powder for shaping, which calculates the deterioration level of the powder for shaping to be inspected based on the deterioration level.

5. The deterioration degree measuring device for powder for shaping according to claim 4, wherein the powder for shaping is a thermoplastic resin or a metal.

6. The Hansen solubility parameter of the solvent is 14 (J / cm ３ ) １／２ More than 30 (J / cm ３ ) １／２ The deterioration level measuring device for powder for shaping according to claim 4 or 5, wherein the deterioration level measuring device is as follows:

7. Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was measured. １ H nucleus spin-spin relaxation time T2 １ The test dispersion obtained by dispersing the used modeling powder to be tested in the solvent was also measured. １ H nucleus spin-spin relaxation time T2 ２ The standard dispersion is measured. １ H nucleus spin-spin relaxation time T2 １ and the test dispersion １ H nucleus spin-spin relaxation time T2 ２ A measurement step of calculating a deterioration degree of the used powder for molding based on the result of the measurement; A generation process of mixing the used modeling powder with the unused modeling powder based on the deterioration degree of the used modeling powder to generate a recycled modeling powder; A method for producing recycled powder for molding having the above structure.

8. Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was measured. １ Spin-spin relaxation time T2 of H nucleus １ The test dispersion obtained by dispersing the used modeling powder to be tested in the solvent was also measured. １ Spin-spin relaxation time T2 of H nucleus ２ The standard dispersion is measured. １ Spin-spin relaxation time T2 of H nucleus １ and the test dispersion １ Spin-spin relaxation time T2 of H nucleus ２ A measurement unit that calculates a deterioration degree of the used modeling powder based on the a generating unit that mixes the used powder for modeling with the unused powder for modeling based on the deterioration degree of the used powder for modeling, and generates recycled powder for modeling; A manufacturing apparatus for recycled powder for modeling comprising:

9. Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was measured. １ H nucleus spin-spin relaxation time T2 １ The test dispersion obtained by dispersing the used modeling powder to be tested in the solvent was also measured. １ H nucleus spin-spin relaxation time T2 ２ The standard dispersion is measured. １ H nucleus spin-spin relaxation time T2 １ and the test dispersion １ H nucleus spin-spin relaxation time T2 ２ A measurement step of calculating a deterioration degree of the used powder for molding based on the result of the measurement; A generation process of mixing the used modeling powder with the unused modeling powder based on the deterioration degree of the used modeling powder to generate a recycled modeling powder; A molding step of molding a three-dimensional object by layered manufacturing using the recycled powder for modeling; A method for manufacturing a three-dimensional object comprising the steps of:

10. Using a pulsed NMR device, a standard dispersion of a standard modeling powder dispersed in a solvent was measured. １ H nucleus spin-spin relaxation time T2 １ The test dispersion obtained by dispersing the used modeling powder to be tested in the solvent was also measured. １ H nucleus spin-spin relaxation time T2 ２ The standard dispersion is measured. １ H nucleus spin-spin relaxation time T2 １ and the test dispersion １ H nucleus spin-spin relaxation time T2 ２ A measurement unit that calculates a deterioration degree of the used modeling powder based on the A generation unit that mixes the used modeling powder with the unused modeling powder based on the deterioration degree of the used modeling powder to generate a recycled modeling powder; a molding unit that molds a three-dimensional object by layered molding using the recycled powder for molding; A three-dimensional object manufacturing apparatus comprising:

11. Using a pulsed NMR device, the dispersion in which the powder for modeling is dispersed in a solvent is １ The spin-spin relaxation time T2 of the H nuclei was measured, and the １ The spin-spin relaxation time T2 of the H nucleus and the １ A deterioration level measuring device for a powder for shaping, which calculates a specific surface area of ​​the powder for shaping based on the spin-spin relaxation time T2 of H nuclei.

12. Using a pulsed NMR device, the dispersion in which the powder for modeling is dispersed in a solvent is １ The spin-spin relaxation time T2 of the H nuclei was measured, and the １ The spin-spin relaxation time T2 of the H nucleus and the １ A method for measuring deterioration of a powder for shaping, which calculates a specific surface area of ​​the powder for shaping based on the spin-spin relaxation time T2 of H nuclei.

13. The deterioration degree measuring method for a powder for shaping according to claim 12, wherein the powder for shaping is a thermoplastic resin or a metal.

14. The Hansen solubility parameter of the solvent is 14 (J / cm ３ ) １／２ More than 30 (J / cm ３ ) １／２ The method for measuring the deterioration degree of a powder for shaping according to claim 12 or 13, wherein the deterioration degree is as follows:

15. The solvent １ The deterioration degree measuring method for a powder for molding according to claim 12 or 13, wherein the spin-spin relaxation time T2 of H nuclei is 1000 ms or more.

16. The deterioration degree measuring method for a powder for shaping according to claim 12 or 13, wherein the deterioration degree of the powder for shaping after use is calculated based on a specific surface area of ​​the powder for shaping before use that has been measured and calculated in advance.

17. The used powder for molding is sampled, and a pulse NMR device is used to measure the dispersion of the used powder for molding in a solvent. １ The spin-spin relaxation time T2 of the H nuclei was measured, and the １ The spin-spin relaxation time T2 of the H nucleus and the １ A measuring step of calculating a specific surface area of ​​the used powder for shaping based on the spin-spin relaxation time T2 of H nuclei; A generation process of mixing the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling to generate recycled powder for modeling; A method for producing recycled powder for molding having the above structure.

18. The used powder for molding is sampled, and a pulse NMR device is used to measure the dispersion of the used powder for molding in a solvent. １ The spin-spin relaxation time T2 of the H nuclei was measured, and the １ The spin-spin relaxation time T2 of the H nucleus and the １ A measuring unit for calculating a specific surface area of ​​the used powder for modeling based on the spin-spin relaxation time T2 of H nuclei; a generating unit that mixes the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling, and generates recycled powder for modeling; A manufacturing apparatus for recycled powder for modeling comprising:

19. The used powder for molding is sampled, and a pulse NMR device is used to measure the dispersion of the used powder for molding in a solvent. １ The spin-spin relaxation time T2 of the H nuclei was measured, and the １ The spin-spin relaxation time T2 of the H nucleus and the １ A measuring step of calculating a specific surface area of ​​the used powder for shaping based on the spin-spin relaxation time T2 of H nuclei; A generation process of mixing the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling to generate recycled powder for modeling; A molding step of molding a three-dimensional object by layered manufacturing using the recycled powder for modeling; A method for manufacturing a three-dimensional object comprising the steps of:

20. The used powder for molding is sampled, and a pulse NMR device is used to measure the dispersion of the used powder for molding in a solvent. １ The spin-spin relaxation time T2 of the H nuclei was measured, and the １ The spin-spin relaxation time T2 of the H nucleus and the １ A measuring unit for calculating a specific surface area of ​​the used powder for modeling based on the spin-spin relaxation time T2 of H nuclei; A generation unit that mixes the used powder for modeling with the powder for modeling before use based on the specific surface area of ​​the used powder for modeling to generate recycled powder for modeling; a molding unit that molds a three-dimensional object by layered molding using the recycled powder for molding; A three-dimensional object manufacturing apparatus comprising:

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