Method for manufacturing three-dimensional objects and products

Abstract

This technology is suitable for removing unwanted parts from ceramic molded objects. [Solution] A method for manufacturing a three-dimensional object, comprising: an additive manufacturing step of additively manufacturing an object having a first part 1 and a second part 2 located near the first part 1 using ceramic powder; and a removal step of removing the second part 2 of the additively manufactured object while leaving the first part 1 intact by blasting the object with media, wherein the Young's modulus of the media is lower than the Young's modulus of the first part 1.

Description

[Technical Field]

[0001] This technology relates to a method for manufacturing three-dimensional objects. [Background technology]

[0002] For applications such as quickly creating prototypes or manufacturing small quantities of parts, additive manufacturing technology for producing three-dimensional objects is becoming widespread. Additive manufacturing eliminates the need for molds, allowing for direct fabrication and enabling the production of highly accurate three-dimensional objects in a short time. Furthermore, because fabrication can be based on three-dimensional data created using design tools such as 3D CAD, design changes are easy, and it has the advantage of being able to manufacture three-dimensional objects with complex and intricate shapes. In recent years, additive manufacturing methods using ceramic powder as a material have also been proposed. In additive manufacturing, if the final object to be produced (hereinafter sometimes referred to as the "main body") has a protruding shape, or so-called overhang, it is common practice to create a three-dimensional object by adding supports to the main body to support the overhang. Furthermore, if the shape of the main body is complex and intricate, it may be prone to damage during printing, so supports may also be created to support that part. Thin columnar or lattice-shaped supports are commonly used. These supports become unnecessary after printing and are removed using tools. Patent documents 1 and 2 disclose a configuration for removing unwanted parts adhering to a molded object made of a metal or resin material by blasting. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-095946 [Patent Document 2] Japanese Patent Publication No. 2016-113701 [Overview of the project] [Problems that the invention aims to solve]

[0004] To separate a three-dimensional object printed on a substrate, one can simply cut it linearly using a wire saw or similar tool. However, when removing supports attached to the object using tools (such as a rotary tool or wire saw), the following problems arise. First, it is difficult to remove the supports with high precision along the shape of the object. Second, the object may be damaged if the tool accidentally touches it. This is especially true for brittle ceramic materials, which are prone to damage. As a result, there have been issues such as a decrease in the quality of the object and the object's shape being restricted to shapes that can be used with tools. This disclosure addresses the above-mentioned problems and provides a technology suitable for removing unwanted parts from ceramic fabricated objects. [Means for solving the problem]

[0005] A first aspect of this disclosure is a method for manufacturing a three-dimensional object, A layered fabrication process for layering a layered object having a first part and a second part located near the first part, using ceramic powder. A removal step of removing the second part of the additively manufactured object while leaving the first part intact by blasting the additively manufactured object with media, It has, The Young's modulus of the media is characterized by being lower than the Young's modulus of the first portion.

[0006] A second aspect of this disclosure is a product, A container containing ceramic powder, The container includes a medium for blast processing of a molded object made using the aforementioned ceramic powder, The Young's modulus of the media is characterized by being lower than the Young's modulus of the ceramic particles in the ceramic powder. [Effects of the Invention]

[0007] According to the present disclosure, a technique advantageous for appropriately removing unnecessary portions from a ceramic shaped object can be provided.

Brief Description of the Drawings

[0008] [Figure 1] It is a schematic cross-sectional view showing an example of a three-dimensional shaped object before support removal. [Figure 2] It is a schematic cross-sectional view showing an example of a support. [Figure 3] It is a schematic cross-sectional view showing an example of a support in a lattice shape. [Figure 4] It is a conceptual diagram showing an example of a laminating and shaping process using a powder bed fusion method. [Figure 5] It is a schematic diagram showing an example of a blasting device. [Figure 6] It is a schematic diagram for explaining the behavior of an object when blasting is performed. [Figure 7] It is a flowchart showing an example of the manufacturing method of the present embodiment. [Figure 8] It is a schematic diagram showing a shaped object for evaluation manufactured in an example.

Modes for Carrying Out the Invention

[0009] Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following specific examples and drawings. In the present embodiment, an apparatus using a powder bed fusion method will be described as an example, but other types of three-dimensional shaping apparatuses may be used.

[0010] The method for manufacturing a three-dimensional shaped object according to the present embodiment includes a laminating and shaping step of laminating and shaping a laminated shaped object having a first part and a second part located in the vicinity of the first part using ceramic powder, and a removing step of removing the second part while leaving the first part of the laminated shaped object by blasting in which a medium is collided with the laminated shaped object.

[0011] <Three-dimensional objects (additive-formed objects)> Figure 1 is a schematic cross-sectional view showing an example of a three-dimensional object before support removal. In this embodiment, a three-dimensional object is created that includes a first part 1 as shown in Figure 1 and a second part 2 located nearby thereto. Here, the first part 1 refers to the main body (the article to be ultimately obtained), and the second part 2 refers to the support. According to this embodiment, it is possible to provide a method for manufacturing a three-dimensional object that can remove unnecessary support parts while suppressing deterioration of the article's quality due to damage to the main body and deterioration of the article's performance due to constraints on the shape of the main body.

[0012] Figure 2 is a schematic cross-sectional view showing an example of the second part, the support. For example, as shown in Figure 2(A), the support (second part) 2 is formed on the molding stage 3 to support the lower part of the overhang portion of the main body (first part) 1. At this time, the lower part of the overhang portion of the main body 1 and the support 2 are formed in contact.

[0013] For example, as shown in Figure 2(B), support 2 is formed on the build stage 3 so as to surround the main body 1, which is in the shape of a thin column or thin plate. During the three-dimensional build process, the 3D object is subjected to load when the powder is spread onto the build stage by the recoater. This load may cause damage to the main body 1, which is in the shape of a thin column or thin plate. Therefore, by surrounding the main body 1, which is in the shape of a thin column or thin plate, with support 2, the load is prevented from being transmitted to the main body 1, thereby preventing damage. At this time, support 2 and the main body 1, which is in the shape of a thin column or thin plate, may be in close contact, or there may be a gap to improve the ease of support removal in subsequent processes. The gap between support 2 and the main body 1, which is in the shape of a thin column or thin plate, may be, for example, 5 mm or less, or 3 mm or less. By setting the gap between support 2 and the main body 1, for example, to 5 mm or less, damage to the main body 1, which is in the shape of a thin column or thin plate, can be prevented.

[0014] In this embodiment, support 2 can be formed, for example, by stacking layers uniformly irradiated over a predetermined area under predetermined laser conditions, but is not limited to this. In general three-dimensional fabrication using metal or resin materials, thin columnar or lattice shapes are used as support 2. Figure 3 is a schematic cross-sectional view showing an example of a lattice-shaped support. However, ceramics are brittle materials and do not elastically deform when a load is applied by the powder-spreading member during powder spreading in fabrication, so thin columns or lattices may break and may cease to function as supports. Therefore, it is preferable that at least the surface of support 2 facing the main body 1 has a uniform structure.

[0015] <Additive Manufacturing Process> The additive manufacturing process involves additively manufacturing an object having a first part and a second part located near the first part, using ceramic powder. The ceramic powder used for manufacturing is composed of a large number of ceramic particles. The additive manufacturing process is preferably a powder bed fusion process. The powder bed fusion method may be SLS (Selective Laser Sintering), MJF (Multi Jet Fusion), or SLM (Selective Laser Melting), but it is preferable to use the SLM or SLS method.

[0016] The ceramic powder of this embodiment is suitably used in additive manufacturing, where the ceramic powder is irradiated with laser light according to slice data generated based on three-dimensional data of the ceramic object to be manufactured. This embodiment describes a method of manufacturing using laser light. Specifically, it is used in a manufacturing method using powder bed fusion. The manufacturing process involves alternating between the following placement step and irradiation step multiple times to produce the ceramic object.

[0017] The method for manufacturing a ceramic molded object according to this embodiment includes a placement step of placing ceramic powder on a base and an irradiation step of irradiating part or all of the ceramic powder with laser light to melt and solidify the ceramic particles in the irradiated area to obtain an intermediate molded object.

[0018] When fabricating using powder bed fusion, the placement and irradiation processes involve spreading ceramic powder to a predetermined thickness on the substrate and then irradiating it with laser light.

[0019] The additive manufacturing process of this embodiment preferably includes a placement step of arranging ceramic powder, a step of irradiating the ceramic powder with laser light to form the main body, and a step of irradiating the ceramic powder with laser light to form supports.

[0020] The ceramic powder of this embodiment is preferably a powder mainly composed of ceramics. The ceramic powder only needs to contain ceramics as its main component, and may also contain minor components. Examples of minor components include sintering aids, absorbers, and components that can form a eutectic with the main component. Here, ceramics refers to solid inorganic compounds excluding metals, and the solid bonding state is irrelevant. In this specification, inorganic compounds refer to oxides, nitrides, oxynitrides, carbides, or borides containing one or more elements from the group of elements that includes antimony and bismuth, in addition to the elements from groups 1 to 14 of the periodic table excluding hydrogen.

[0021] The ceramic powder of this embodiment may consist of one type of inorganic compound, or it may be a mixture of two or more types of inorganic compounds. A powder mainly composed of ceramics refers to a powder in which 90 mol% or more of the powder is ceramic. If multiple types of ceramics are included, it is sufficient if their total amount is 90 mol% or more.

[0022] The ceramic powder of this embodiment may use a combination of a base material particle as the main component and a material that absorbs laser light and generates heat. The central particle size of the base material particle is preferably 1 μm or more and 200 μm or less, and more preferably 10 μm or more and 100 μm or less. The central particle size of the material that absorbs laser light and generates heat is preferably smaller than that of the base material particle. If the base material particle has the function of absorbing laser light and generating heat, it can also be used alone.

[0023] There are no restrictions on the wavelength of the laser light used for fabrication, but lasers with a wavelength around 1000 nm, such as Nd:YAG lasers and Yb fiber lasers, are preferably used. The ceramic powder in this embodiment preferably contains components that absorb and generate heat from laser light with a wavelength around 1000 nm. To improve fabrication accuracy, it is preferable to use a laser adjusted to a desired size, such as a diameter of 10 μm to 2 mm. Focal size is one of the parameters that affects fabrication accuracy; to achieve a fabrication accuracy of 100 μm (0.1 mm), depending on the situation, it is preferable that the line widths are similar, and a focal size of 100 μm or less in diameter is preferable. The irradiation of the laser light can be continuous or pulsed.

[0024] Figure 4 is a conceptual diagram showing an example of an additive manufacturing process using powder bed fusion (infrared laser fusion). The basic manufacturing flow of the additive manufacturing process using infrared laser fusion will be explained using Figures 4(a) to 4(h).

[0025] As shown in Figure 4(a), first, powder 101 is placed on a base 130 installed on a stage 151, and then spread to a predetermined thickness with a roller 152 to form a powder layer 102 as shown in Figure 4(b). Here, the powder that forms the main body and the powder that forms the support may be the same or different, but it is preferable that they be the same. As shown in Figure 4(c), a laser beam emitted from a laser light source 180 is irradiated onto the powder layer 102 while scanning with a scanner unit 181 based on slice data generated from the shape data of a desired three-dimensional model. Here, the laser irradiation conditions for forming the main body and the laser irradiation conditions for forming the support may be the same or different, but it is preferable that they be different. Within the irradiation range of the laser beam, the raw material powder melts and then solidifies, forming a solidified section 100 corresponding to the slice data for one layer, and unsolidified powder 103 remains outside the irradiation range of the laser beam. Next, as shown in Figure 4(d), the stage 151 is lowered to form a new powder layer 102 on top of the solidification section 100, and as shown in Figure 4(e), a laser beam is irradiated based on the slice data. As shown in Figure 1(f), this series of steps is repeated a number of times according to the slice data to obtain a three-dimensional object 110. Finally, as shown in Figure 4(g), the unsolidified powder 103 is removed, and as shown in Figure 4(h), the three-dimensional object 110 is separated from the base 130.

[0026] <Removal process> The removal process involves blasting the additively manufactured object, which removes the second part of the object while leaving the first part intact. The media used in blasting consists of numerous media particles.

[0027] Figure 5 is a schematic diagram showing an example of a blasting apparatus. The blasting apparatus comprises a stage 71, a drive unit 72, and a nozzle 73. The stage 71 supports the object to be blasted. The drive unit 72 is connected to the stage 71 and moves the stage 71 along direction S. The drive unit 72 is, for example, a servo cylinder. The nozzle 73 is fixedly positioned opposite the stage 71. The nozzle 73 sprays media together with air onto the surface of the object on the stage 71. The nozzle 73 is, for example, a direct-pressure air nozzle. The blasting apparatus 70 includes a control unit (not shown) that controls the drive amount of the drive unit 72 and the spray pressure of the nozzle 73. By controlling the drive amount of the drive unit 72 and the spray amount of the nozzle 73, the control unit can blast a predetermined position of the object for a predetermined time.

[0028] The media can be selected from a variety of materials, including resins, metals, and ceramics. For example, resins such as acrylic, polycarbonate, nylon, and polyester are available. Metals such as iron, stainless steel, zinc, aluminum, and copper are available. Ceramics such as silicon carbide, alumina, zircon, and glass are available. Furthermore, the central particle size of the media varies from a few micrometers to a few millimeters, allowing for appropriate selection according to the shape and purpose.

[0029] Note that the blasting apparatus is not limited to the apparatus shown in Figure 5. For example, the nozzle 73 may be configured to move relative to the stage 71. In this case, the blasting apparatus does not need to have a drive unit 72. Furthermore, the apparatus may not have a stage 71 or a drive unit 72, and the molded object may be supported and moved by hand. The nozzle 73 may be a suction-type air nozzle. The drive unit 72 may be a hydraulic cylinder or an air cylinder.

[0030] In this embodiment, the blasting conditions are set to conditions that allow the support to be removed at a predetermined speed.

[0031] Generally, blasting allows for machining specific locations on an object. However, the bodies created using 3D printing often have complex shapes, and the 3D printed objects tend to have intricate structures where the body and supports are intertwined. In such cases, it is difficult to make the media collide only with the supports that need to be removed. Therefore, during blasting, the media collides with both the body and the supports.

[0032] To remove only the support while impacting both the main body and the support with media, it is necessary to ensure that only the support is selectively destroyed during the blasting process. The inventors have found that this can be achieved by giving the Young's modulus of the main body and the media, and preferably the Young's modulus of the support, specific characteristics. The method for measuring the Young's modulus in this embodiment will be described later. Note that the Young's modulus of the main body and support in this embodiment refers to the Young's modulus of the material, not the Young's modulus of the structure itself.

[0033] The inventors have found that to selectively destroy only the supports, it is effective to make the Young's modulus of the media lower than that of the main body. When the Young's modulus of the media used in blasting is lower than that of the main body, the main body will not be abraded even if it collides with the media during blasting, making it possible to selectively destroy only the supports. The Young's modulus of the media may also be lower than that of the supports.

[0034] Furthermore, the inventors have found that it is desirable for the difference between the Young's modulus of the media and the Young's modulus of the main body to be 30 [GPa] or more. When the difference between the Young's modulus of the media and the Young's modulus of the main body is 30 [GPa] or more, it becomes possible to selectively destroy only the supports while further suppressing damage to the main body. The larger the difference between the Young's modulus of the media and the Young's modulus of the main body, the more advantageous it is in terms of selectivity, and it is preferable for the difference between the Young's modulus of the media and the Young's modulus of the main body to be 50 [GPa] or more. If the difference between the Young's modulus of the media and the Young's modulus of the main body is made extremely large, it may result in significant constraints on the moldability of the main body or require a great deal of time to process the supports. In these respects, it is preferable for the difference between the Young's modulus of the media and the Young's modulus of the main body to be, for example, 470 [GPa] or less, and it may also be 300 [GPa] or less.

[0035] Furthermore, the inventors have found that it is desirable for the media's Young's modulus to be 20 [GPa] or less. When the media's Young's modulus is 20 [GPa] or less, it becomes possible to selectively break only the support while further suppressing damage to fine structures such as the edges of the main body and thin plates. If the media's Young's modulus is extremely small, the media is too soft, making it difficult to apply force to the support even when it collides with it, which may require a great deal of time to process the support. In terms of the efficiency of support removal, the media's Young's modulus is preferably, for example, 0.1 [GPa] or more, and may also be 1 [GPa] or more.

[0036] Furthermore, the inventors have found that it is desirable for the Young's modulus of the main body to be 50 [GPa] or higher. When the Young's modulus of the main body is 50 [GPa] or higher, the strength of the edge portion of the main body increases. As a result, it becomes possible to selectively break only the support while further suppressing damage to fine structures such as the edge portion of the main body and thin plates. Since damage can be suppressed as the Young's modulus of the main body increases, it is preferable for the Young's modulus of the main body to be 100 [GPa] or higher. If the Young's modulus of the main body is made extremely large, it may become difficult to mold the main body and / or support. A suitable Young's modulus of the main body in terms of moldability of the main body and / or support is, for example, 500 [GPa] or less or 470 [GPa] or less, and may also be 300 [GPa] or less.

[0037] Furthermore, the inventors have found that it is desirable for the media to be made of a resin material. Because resins generally have an elastic structure, it is possible to selectively break only the supports while further suppressing damage to fine structures such as the edges and thin plates of the main body. In addition, in ceramic fabrication, the strength of the main body is increased by firing. Therefore, if the media is made of a resin material, even if some media remains on the main body, it will disappear during firing, so the main body will not be contaminated.

[0038] Furthermore, the inventors have found that it is desirable for the central particle size of the media to be 3 mm or less. A smaller central particle size of the media makes it possible to remove supports in fine structures such as smaller holes, gaps, and depressions. The smaller the central particle size of the media, the higher the accuracy of support removal, so the central particle size of the media is preferably 1 mm or less, and may be 0.5 mm or less. If the central particle size of the media is extremely small, the kinetic energy of the media is too small, so even if it collides with a support, it is difficult to apply force to the support, and processing the support may take a considerable amount of time. In terms of the efficiency of support removal, the central particle size of the media is preferably, for example, 0.01 mm or more, also preferably 0.05 mm or more, and may be 0.1 mm or more. The method for measuring the central particle size in this embodiment will be described later.

[0039] Furthermore, the inventors have found that the circularity of the media should be between 0.75 and 1, and more preferably between 0.80 and 1. When the circularity of the media is 0.75 or higher, the shape of the media approaches a spherical shape without edges, thus reducing the cutting force. Therefore, damage to the main body can be suppressed during blasting.

[0040] <Internal structure of the support (part 2)> The main body is an item that should remain intact and therefore needs to be strong enough to prevent breakage. For this reason, it is preferable that the main body be molded with minimal internal voids to achieve sufficient strength. On the other hand, since the support structure needs to be removed after molding, it is preferable that it be molded with more internal voids to make it more fragile. The difference in voids between the main body and the support structure can be achieved by changing the molding conditions.

[0041] After the 3D printing process is complete, the supports need to be removed. In this embodiment, the supports are removed by blasting, which involves impacting the media.

[0042] The behavior of an object after blasting will be explained using Figure 6. Figure 6 is a schematic diagram illustrating the behavior of an object after blasting. Figure 6(A) shows an example where the particles constituting the object are dense and there are few voids inside, specifically a state where there are no voids inside. Figure 6(B) shows a state where the particles constituting the object are coarse and there are voids inside. These voids may be individual voids or interconnected voids formed by multiple voids linked together.

[0043] The support preferably has an internal cavity, or in other words, a shape with many cracks (internal defects), as shown in Figure 6(B). In this case, when the support is subjected to impact from the media collision during blasting, stress concentration occurs due to the cracks, causing brittle fracture, i.e., the support breaks. As a result, the support is removed by blasting.

[0044] On the other hand, it is preferable that the main body has few internal voids, or in other words, a shape with few cracks, as shown in Figure 6(A). In this case, even if the media is impacted during blasting, stress concentration is less likely to occur, and brittle fracture is less likely to occur; that is, the main body is less likely to break. As a result, the main body is not removed by blasting.

[0045] As a result, when sandblasting a printed object, it is possible to more selectively remove only the supports.

[0046] Furthermore, if the shape shown in Figure 6(B) is created using metal or resin materials and subjected to blast processing, it will undergo plastic deformation due to the impact of the media, making brittle fracture unlikely. Therefore, when using metal or resin materials, it is difficult to remove supports like those in Figure 6(B) by blast processing.

[0047] The inventors have found that by giving the internal structure of the support, particularly the surface area of ​​the voids, a distinctive feature, it is effective to selectively destroy only the support during blast processing. Furthermore, they have found that measuring the sum of the perimeters of the voids in the main body and the support cross-section is preferable as an indicator of the state of the void surface area. The method for measuring the sum of the perimeters of the voids in the main body and the support cross-section in this embodiment will be described later.

[0048] Furthermore, the inventors have found that in order to selectively break only the support, it is effective to make the sum of the perimeters of the voids in the support cross-sections larger than the sum of the perimeters of the voids in the main body cross-sections.

[0049] In this embodiment, by controlling the molding conditions, such as the laser irradiation conditions, the main body and the support can be fabricated to have different internal structures. Since the main body needs to have sufficient strength, it is preferable that it be fabricated to have a dense structure with few voids inside, as shown in Figure 6(A). On the other hand, it is preferable that the support has a structure with voids inside, as shown in Figure 6(B).

[0050] Furthermore, the inventors have found that it is desirable that the sum of the circumferences of the pore portions of the support cross-section is 7000 μm / mm 2 or more. The sum of the circumferences of the pore portions of the support cross-section is an index representing the degree of pores inside the support. A larger numerical value means more pores and a more complex pore shape. When the sum of the circumferences of the pore portions of the support cross-section is 7000 μm / mm 2 or more, the joints between the particles constituting the support become a shape with even more joints. As a result, when the media is collided and impacted during blasting, the locations where stress concentrates further increase, making brittle fracture more likely to occur. Since the support is more likely to be broken as the sum of the circumferences of the pore portions of the support cross-section has a larger value, the sum of the circumferences of the pore portions of the support cross-section is preferably 10000 μm / mm 2 or more, more preferably 20000 μm / mm 2 or more. In terms of the formability of the support, the sum of the circumferences of the pore portions of the support cross-section is preferably, for example, 100000 μm / mm 2 or less, 80000 μm / mm 2 or less, 75000 μm / mm 2 or less, 70000 μm / mm 2 or less is more preferable, and it may be 50000 μm / mm 2 or less.

[0051] Regarding the method of making the sum of the circumferences of the pore portions of the support cross-section 7000 μm / mm 2 or more, the powder bed fusion bonding method will be described as an example.

[0052] In the powder bed fusion bonding method, the laid powder is irradiated with a laser to melt the powder to form the main body and the support. Then, the process of laying the powder and irradiating with the laser is repeated. Generally, the powder laying thickness per layer is set to several tens of μm, and it is ideal to melt this thickness of the powder layer. The laser irradiation conditions for melting the powder are often set considering the energy density. If the energy density is high, melting can be promoted, and if the energy density is low, melting may be insufficient, so an optimal energy density is set to melt the powder layer.

[0053] Generally, when a powder layer is melted, heat is conducted through the material, reheating the already formed body and supports. The inventors have found that this reheating slightly advances the melting of the support parts, reducing the amount of voids, which can make the supports less likely to break during blasting.

[0054] The inventors have found that even when the same energy density is applied, the effect on the support structure differs depending on the laser conditions. For example, when it is desired to apply a predetermined energy density during fabrication, both "low laser output and slow laser scanning speed" and "high laser output and fast laser scanning speed" are possible. When "low laser output and slow laser scanning speed" is applied, the material is heated for a longer period due to laser irradiation. As a result, the time for heat conduction is also longer, and the already fabricated body and supports are more likely to be reheated. Consequently, the melting of the support structure due to reheating may slightly progress, potentially reducing the amount of voids. On the other hand, when "high laser output and fast laser scanning speed" is applied, the time the material is heated by laser irradiation is shorter. As a result, the time for heat conduction is reduced, and the already fabricated supports are less likely to be reheated. Consequently, melting of the support structure due to reheating can be suppressed, and the amount of voids can be maintained.

[0055] Furthermore, the inventors have found that the sum of the perimeter lengths of the voids in the support cross section is 2000 μm / mm greater than the sum of the perimeter lengths of the voids in the main body cross section. 2 It was found that it is desirable to form them to be larger than the above. The sum of the perimeter lengths of the voids in the support cross section should be 2000 μm / mm compared to the sum of the perimeter lengths of the voids in the main body cross section. 2 If the difference is greater than this, the difference in brittle fracture susceptibility between the main body and the support becomes large. As a result, the main body's fragility becomes sufficiently smaller than that of the support, allowing the support to be removed while minimizing damage to the main body. The sum of the perimeter lengths of the voids in the support cross-section should be 2000 μm / mm greater than the sum of the perimeter lengths of the voids in the main body cross-section. 2To increase the size, the number of voids in the main body can be reduced. This can be achieved by adjusting the molding conditions, adjusting the central particle size of the ceramic powder, for example, by selecting a ceramic material with a small central particle size. The larger the difference in perimeter length between the support cross-section and the main body cross-section, the easier it is to break the support while minimizing damage to the main body. Therefore, the sum of the perimeter lengths of the voids in the support cross-section is preferably 5000 μm / mm greater than the sum of the perimeter lengths of the voids in the main body cross-section. 2 More preferably 15,000 μm / mm 2 The above is formed to a large size. In terms of the formability of the main body and / or support, the difference in the perimeter length of the void between the support cross-section and the main body cross-section is, for example, 100,000 μm / mm. 2 Preferably, it is 75,000 μm / mm 2 It is more preferable that the following conditions are met: 50,000 μm / mm 2 The following is also acceptable.

[0056] Furthermore, the inventors focused on the standard deviation of the perimeter of the void portion of the support cross-section. The standard deviation of the perimeter of the void portion of the support cross-section can be, for example, 100 or more, 200 or more, or 300 or more. The inventors found that it is desirable for the standard deviation of the perimeter of the void portion of the support cross-section to be 400 or more. Generally, stress concentration points occur in areas where the shape changes. When there is a large variation in void size, stress concentration points occur not only in areas where the shape changes due to the voids but also in areas where the density of the void size changes, so the number of stress concentration points increases compared to when the void size is uniform. Therefore, brittle fracture is more likely to occur. By setting the standard deviation of the perimeter of the void portion of the support cross-section to 400 or more, the support becomes more prone to brittle fracture, and the support can be removed with a weaker blast pressure, thus reducing damage to the main body. The larger the standard deviation of the perimeter of the void portion of the support cross-section, the easier the support is to break, so it is preferable for the standard deviation of the perimeter of the void portion of the support cross-section to be 500 or more. Making the standard deviation of the perimeter of the support cross section extremely large may reduce the moldability of the support; therefore, the standard deviation of the perimeter of the support cross section may be, for example, 5000 or less, 4000 or less, 1000 or less, or 600 or less. The method for measuring the standard deviation of the perimeter of the main body and the support cross section in this embodiment will be described later.

[0057] According to the inventors' studies, when using a ceramic material powder with a broad particle size distribution, variations in the size of the gaps between particles are more likely to occur, thus increasing the standard deviation of the perimeter length of the voids in the support cross-section. As a method for broadening the particle size distribution, for example, a mixed powder of multiple ceramic powders with different central particle sizes may be used. The effect is more readily obtained when multiple ceramic materials with different central particle sizes make up a larger proportion of the powder. As a result, variations in the size of the gaps between particles are more likely to occur, thus increasing the standard deviation of the perimeter length of the voids in the support cross-section.

[0058] Furthermore, the inventors have found that it is desirable for the proportion of the perimeter of the voids in the support cross-section to be 100 μm or larger to be 25% or more. Increasing the number of relatively large voids thins the wall thickness between voids, making them more susceptible to brittle fracture. Therefore, the support can be removed with weaker blast pressure, thus reducing damage to the main body. According to the inventors' studies, increasing the laser scanning interval can increase the number of large voids. The larger the proportion of the voids in the support cross-section to be 100 μm or larger, the easier it is for the support to break, so it is preferable for the proportion of the voids in the support cross-section to be 100 μm or larger to be 35% or more. The proportion of the voids in the support cross-section to be 100 μm or larger may be, for example, 75% or less, 65% or less, or 55% or less.

[0059] <Other processes> Figure 7 is a flowchart showing an example of the manufacturing method according to this embodiment. As shown in Figure 7, the manufacturing method according to this embodiment may include other steps such as steps S1-S3 and step S5, in addition to the additive manufacturing step (step S4) and the removal step (step S6).

[0060] First, prepare the shape data for the main body (step S1). Next, based on the shape data of the main body, the shape of the support that supports the main body is designed and the shape data of the support is prepared (step S2). For example, the support may be designed to support an overhang portion of the main body that protrudes from below in the direction of printing, as shown in Figure 2(A), or to surround a thin column shape that is prone to damage during printing, as shown in Figure 2(B).

[0061] Next, the 3D printing device creates slice data for each layer necessary to build the object in layers, i.e., slice data for the main body and support parts (step S3). The created slice data is stored in a memory device (not shown) within the 3D printing device.

[0062] Next, as part of the additive manufacturing process, a three-dimensional object is created using a three-dimensional 3D printer (step S4). As mentioned earlier, the object is created by irradiating the powder layer with a laser beam based on the slice data of the main body and support parts. In other words, a three-dimensional object including the main body and support parts is created.

[0063] After the unsolidified powder is removed, the molded object is separated from the base using a wire saw or the like (step S5). Next, as a removal step, the molded object is subjected to blasting (step S6). The supports are removed by blasting, and the main body is removed. After the removal step, there may be a firing step in which the main body is fired.

[0064] <Measurement Method> [Young's modulus] The method for measuring Young's modulus in this embodiment will now be described. In this embodiment, Young's modulus is measured by the nanoindentation method. The nanoindentation method is a technique that calculates a mechanical quantity from a load-displacement curve obtained by continuously measuring the load and displacement during the process of pressing an indenter into the surface of a sample and removing the load. All Young's moduli described in this embodiment were measured under the following conditions.

[0065] • Equipment used: Nanoindenter (TI 950 TriboIndenter, manufactured by BRUKER) • Indenter used: Berkovich indenter (model number: TI-0039, manufactured by BRUKER) • Push-in control method: Displacement control method (lift operation not used) • Maximum indentation depth: 100nm • Push rate: 10nm / second • Loading time: 10 seconds (pressing from 0 to 100 nm) ·Holding time: 5 seconds (100nm constant) • Unloading time: 10 seconds (returning from 100 nm to 0 nm) • Number of measurements: 5

[0066] [Center particle size] The method for measuring the central particle size in this embodiment is described below. The central particle size used in this embodiment was evaluated using a scanning electron microscope (SEM)-energy dispersive X-ray spectroscopy (EDX). Hereafter, scanning electron microscope-energy dispersive X-ray spectroscopy may be referred to as SEM-EDX. Specifically, first, a portion of the material powder is taken as a sample, and the type of raw material is determined by elemental mapping using EDX. At this time, 20 images are obtained for each sample at an observation magnification of 500x. The major and minor axes are measured for all particles that are fully visible in the obtained images. The average of the major and minor axes is taken as the primary particle size of each individual particle, and these are aggregated for each determined type of raw material. The number average of the primary particle sizes obtained in this way is taken as the central particle size for each raw material.

[0067] [Sum of the perimeter lengths of the voids in the cross-section, standard deviation of the perimeter lengths of the voids in the cross-section] This section describes how to measure the sum of the perimeters of the voids in the main body and support cross-sections, and the standard deviation of the perimeters of the voids in the main body and support cross-sections in this embodiment.

[0068] The sum of the perimeters of the voids in the main body and support cross-sections is measured using the following procedure. (1) Obtain a SEM image of the cross-section of the object. (2) The sum of the perimeters L of the voids in the cross-sectional image using software such as imageJ. n We seek. (3) Polish the object to reveal a new cross-section. (4) Perform the same procedure as in (1) and (2), and sum the perimeter lengths L of the new cross-sections of the voids. n+1 We seek. (5) Repeat steps (1) through (4) a predetermined number of times. (6) The average of the sum of the measured perimeters of the voids is defined as the sum of the perimeters of the voids in the object.

[0069] The SEM equipment and observation conditions are as follows: Equipment used: ULTRA PLUS manufactured by Carl Zeiss Microscopy Co., Ltd. Acceleration voltage: 5.0kV WD: 4.0mm Aperture Size: 30.0 μm Detection signal: EsB (Energy-selective backscattered electrons) EsB Grid: 300V Observation magnification: 50x Contrast: 35.0 ± 5.0% (reference value) Brightness: 50.0 ± 5.0% (reference value) Resolution: 1024×768

[0070] In procedure (2), the sum of the perimeter lengths of the dark regions relative to the total area of ​​the backscattered electron image was obtained by analyzing the backscattered electron image of the object cross-section obtained by the above method using the image processing software ImageJ (developed by Wayne Rashand). The procedure is shown below.

[0071] First, convert the backscattered electron image to 8-bit using the Type option in the Image menu. Next, remove the information display area from the SEM image by cropping. This can be done by selecting the area excluding the information display area from the SEM image using the Rectangle Tool on the toolbar, and then clicking Crop in the Image menu. Next, reduce image noise by setting the Median diameter to 2.0 pixels using Filters in the Process menu. Next, select Threshold from Adjust in the Image menu. Select Default, click Auto, and then click Apply to obtain a binarized image. This operation displays the dark areas of the backscattered electron image in black. Here, the dark areas indicate voids in the cross-section. Next, extract the outline of the voids by selecting Outline from Binary in the Process menu. Next, set the measurement items. This can be set using Set Measurement in the Analyze menu. In this embodiment, Perimeter is selected. Next, set various items using Analyze Particles in the Analyze menu. In this embodiment, the settings are as follows.

[0072] • Size (pixel^2): 0 - Infinity • Circularity: 0.00-1.00 Check the boxes for "Display results", "Clear results", and "Summarize".

[0073] After making the above settings, pressing the OK button will start the SEM image measurement.

[0074] After the measurement is complete, refer to the "Summary" and record the average perimeter and the number of voids. Then, calculate the value L by multiplying the average perimeter by the number of voids and dividing by the area of ​​the SEM image used for the measurement. Also, since the perimeters of all measured voids are recorded in the "Result" window, calculate the standard deviation D of the void circumference from this record. Furthermore, calculate L and D for multiple different cross-sections and find the average value L. ave and D ave The value of L is calculated. In this example, the observed cross-section is polished by 1 mm to obtain a new cross-section and L is calculated. This is repeated 10 times to obtain L. ave and D ave Calculate L. In this example, this L ave This is called the sum of the perimeter lengths of the voids. As can be seen from the calculation process above, this sum of the perimeter lengths of the voids is equivalent to the surface area of ​​the voids inside the object being measured. Also, in this embodiment, this D ave This is called the standard deviation of the perimeter of the void.

[0075] Furthermore, the "Result" window calculates the percentage of voids with a perimeter of 100 μm or more from the perimeters of all measured voids.

[0076] [Roundness] In this embodiment, the circularity of the media (blast media) is measured using the following procedure. (1) Obtain a microscopic image of the media. (2) Use software such as imageJ to determine the area A and perimeter P of the media portion. At this time, exclude any media that overlap when photographed, and only calculate for media that are photographed individually. (3) Calculate the circularity based on the following formula (1). Circularity = 4 × π × A / P 2 ...Formula (1) (4) Perform the calculation in (3) for 100 media portions in the microscope image. If the number of individually photographed media is less than 100, repeat (1) to (3) above. (5) The average value of the calculated circularity is defined as the circularity of the media.

[0077] The conditions for acquiring microscopic images from the media are as follows: Equipment used: Keyence VHX-8000 Observation magnification: 10x

[0078] In procedure (2), the area A and perimeter P of the bright region of the microscope image were calculated by analyzing the microscope image obtained using the above method with the image processing software ImageJ (developed by Wayne Rashand). The procedure is shown below.

[0079] First, convert the microscope image to 8-bit using the Type option in the Image menu. Next, remove the information display area from the microscope image by cropping. This can be done by selecting the area excluding the information display area from the microscope image using the Rectangle Tool on the toolbar, and then clicking Crop in the Image menu. Next, reduce image noise by setting the Median diameter to 2.0 pixels using Filters in the Process menu. Next, select Threshold from Adjust in the Image menu. Select Default, click Auto, and then click Apply to obtain a binarized image. This operation displays the bright areas of the microscope image in white. Here, the bright areas represent the media portion. Next, extract the outline of the media portion by selecting Outline from Binary in the Process menu. Next, set the measurement items. This can be set using Set Measurement in the Analyze menu. In this embodiment, select Perimeter. Next, set various items using Analyze Particles in the Analyze menu. In this embodiment, the settings are as follows.

[0080] • Size (pixel^2): 0 - Infinity • Circularity: 0.00-1.00 Check the boxes for "Display results", "Clear results", and "Summarize".

[0081] After making the above settings, pressing the OK button will start the measurement of the microscope image.

[0082] After the measurement is complete, the circularity of 100 media is calculated from the "Perimeter" and "Area" recorded in the "Result" window based on equation (1). The average value of the calculated circularity is taken as the circularity of the media in this embodiment.

[0083] <Product> A product for manufacturing molded objects using the technology of this embodiment may include a container containing ceramic powder for molding and a container containing media for blasting the molded object formed using the ceramic powder. The Young's modulus of the media (media particles) is lower than that of the ceramic particles in the ceramic powder.

[0084] The ceramic powder may contain ceramic particles of multiple materials, but it is preferable to use the Young's modulus of the ceramic particles of the material that accounts for 30% or more by mass in the ceramic powder as the standard. The ceramic particles that serve as the standard for the Young's modulus in the ceramic material powder are preferably those of the material that accounts for the largest mass in the ceramic powder. The Young's modulus of the ceramic particles is preferably 50 [GPa] or higher, and also preferably 100 [GPa]. The Young's modulus of the ceramic particles may be 1000 [GPa] or lower, 750 [GPa] or lower, or 500 [GPa] or lower.

[0085] The media may contain media particles of multiple materials, but it is preferable to use the Young's modulus of the media particles of the material that accounts for 30% or more by mass in the media as the standard. Media particles with a Young's modulus lower than that of ceramic particles are preferably made of resin material.

[0086] By creating a product that combines ceramic powder with a media that is advantageous for properly removing unwanted parts from ceramic molded objects, it is possible to eliminate the hassle of selecting and preparing media for ceramic powder users, thereby providing convenience to users. The containers include bottles and bags.

[0087] The container may include a label listing the contents of the powder. The product may also include documentation describing the molding conditions (recipe) for creating objects using ceramic powder. These conditions may include laser type (wavelength), laser power (intensity), scanning speed, and scanning interval. They may also include the thickness of the powder layer. Furthermore, the product may include documentation describing blasting conditions. By referring to this documentation, users can create objects using molding conditions suitable for ceramic powder. This documentation may also be a product instruction manual. This documentation may be in print or digital format. [Examples]

[0088] Table 1 shows the formulations of the ceramic material powders used in this embodiment. All material powders are mixed in a V-type mixer V20 (manufactured by Tokuju Kogyosho) at 30 rpm for 30 minutes. The ceramic particles that serve as the basis for the Young's modulus in the ceramic material powders are, for example, raw material 1 or raw material 2 in material powders A to F in Table 1. For example, the Young's modulus of SiO2 is 72 to 74 [GPa], the Young's modulus of Al2O3 is 350 to 390 [GPa], the Young's modulus of SiC is 390 to 430 [GPa], and the Young's modulus of B4C is 450 to 460 [GPa].

[0089] [Table 1]

[0090] In material powders A, D, and E, raw material 3, Tb4O7, is contained as a component that absorbs the laser and generates heat. In material powder B, raw material 3, SiO, is contained as a component that absorbs the laser and generates heat. In material powders C and F, raw material 1, SiC, and raw material 2, B4C, absorb the laser and generate heat.

[0091] <Examples 1-21> [Formation of molded objects] Objects for evaluation, as described later, were fabricated. Specifically, a 3D printer ProXDMP300 (manufactured by 3D Systems) was used to form objects with a layer thickness of 25 μm using the same process as shown in Figure 4. Blasting was performed using a blasting device SFCF-3 (manufactured by Fuji Seisakusho) (nozzle diameter 7 mm). The material powders, fabrication conditions, and blasting conditions used in each example are shown in Tables 2, 3, 4, and 5.

[0092] As mentioned above, the blasting pressure is set to a condition that allows the support to be removed at a predetermined speed. Specifically, a cube-shaped support with sides of 30 mm is created under the conditions shown in each embodiment, and the amount of support reduction [mm] is measured when blasting is performed on one face of the support from a vertical direction with the nozzle tip 100 mm away for 10 seconds. This process is repeated while changing the blasting pressure from the nozzle, and the blasting pressure at which the support reduction is 10 mm is set as the blasting pressure for each embodiment.

[0093] [evaluation] The following evaluations were conducted regarding blast processing. Considering practicality, a four-level evaluation scale was used, with A for excellent, B for good, C for acceptable, and D for unacceptable. The results are shown in Tables 2, 3, 4, and 5. Note that there were no unacceptable evaluation items in any of the examples.

[0094] (1) Damage to the main body Body damage refers to the degree of impact on the body shape after blasting. A cube-shaped body section with sides of 30 mm was created under the conditions shown in each example, and the amount of reduction [mm] when blasting was performed on one surface from a distance of 100 mm perpendicular to it for 10 seconds was measured and evaluated according to the following criteria. A: Reduction is less than 0.05 mm B: Reduction of 0.05 mm or more but less than 0.15 mm C: Reduction amount is 0.15mm or more and less than 0.3mm D: Reduction amount is .3mm or more

[0095] (2) Minor damage Micro-damage refers to the degree of impact on the micro-shape of the main body. A main body was created by arranging thin plates 11 with a width of 5 mm, a height of 10 mm, and a thickness ranging from 0.1 mm to 1 mm, as shown in Figure 8(A). A blasting process was performed from the thickness direction for 10 seconds, and the shape after blasting was evaluated according to the following criteria. A: The minimum thickness of thin sheet metal that will not be damaged by blasting is 0.3 mm or less. B: The minimum thickness of thin sheet metal that will not be damaged by blasting is 0.4 mm to 0.6 mm. C: The minimum thickness of thin sheet metal that will not be damaged by blasting is 0.7 mm to 1.0 mm. D: All thin sheets are damaged.

[0096] (3) Removability of fine support Micro-area support removal capability refers to the ease with which supports formed in micro-areas can be removed. As shown in Figure 8(B), a 1mm thick body was drilled with holes 12 of varying diameters from 0.1mm to 1mm, and supports were formed in these holes 12. The amount of remaining supports after blasting was observed and evaluated according to the following criteria. It is desirable that supports in smaller holes can be removed. A: The minimum hole diameter from which the support can be removed is 0.3 mm or less. B: The minimum hole diameter from which the support can be removed is 0.4 mm to 0.6 mm. C: The minimum hole diameter from which the support can be removed is between 0.7 mm and 1.0 mm. The support for the D:1.0mm hole could not be removed.

[0097] [Table 2]

[0098] [Table 3]

[0099] [Table 4]

[0100] [Table 5]

[0101] [Examples 1-6] Examples 1-6 are examples where the difference between the Young's modulus of the main body and the Young's modulus of the media was 30 GPa or more. All of them were evaluated as being practically satisfactory.

[0102] [Examples 7, 8] Examples 7 and 8 use resins with adjusted molecular weights as media, resulting in a higher Young's modulus than in Example 1. In Example 7, where the Young's modulus of the media was 20 [GPa] or less, practically satisfactory results were obtained. On the other hand, in Example 8, where the Young's modulus of the media exceeded 20 [GPa], some damage was observed in the fine details, but it was within a range that did not pose a practical problem.

[0103] [Example 9] Example 9 is an example in which a non-resin material was used as the media. Because the media did not have an elastic structure, some damage occurred to the fine details, but it was within a range that did not pose a practical problem.

[0104] [Example 10] Example 10 uses a ceramic material as the media, and a higher Young's modulus than that used in Example 8. Because the difference between the Young's modulus of the main body and the Young's modulus of the media was less than 30 [GPa], some slight abrasion and damage were observed on the main body, but this was within a range that did not pose a practical problem. Furthermore, due to the high Young's modulus of the media, some slight damage occurred to the fine details, but this too was within a range that did not pose a practical problem.

[0105] [Example 11] Example 11 uses a media with a larger central particle size of 4 mm than in Example 1. Although the support structures in the small holes could not be removed, the support structures in the 1 mm holes could be removed, so there are no practical problems.

[0106] [Examples 12, 13] Examples 12 and 13 are examples in which the fabrication conditions of the support were changed so that the sum of the perimeter lengths of the voids obtained by observing the cross-section of the support was smaller than that of Example 1. The sum of the perimeter lengths of the voids in the support was 7000 [μm / mm²]. 2 In Example 12, where the value was 7000 [μm / mm²] or higher, practically good results were obtained. 2 In Example 13, where the value was less than ], it was necessary to increase the injection pressure to remove the support, which caused some minor damage to the fine details, but this was within a range that did not pose a practical problem.

[0107] [Example 14] Example 14 uses material powder D, in which the central particle size of raw materials 1 and 2 is larger than that of material powder A. By increasing the central particle size of the material powder, the pores in the main body are enlarged, and the support molding conditions are changed to reduce the sum of the perimeter lengths of the port pores. As a result, the difference between the sum of the perimeter lengths of the pores in the main body cross-section and the sum of the perimeter lengths of the pores in the support cross-section is 2000 μm / mm. 2 The result is less than [value missing]. In this example, the brittle fracture susceptibility of the support and the main body was closer than in Example 1, and because the void inside the main body was larger, some brittle fracture occurred in the main body during blasting, and damage to the main body was observed, but it was within a range that did not pose a practical problem.

[0108] [Example 15] Example 15 is an example in which material powder E, in which the central particle size of raw material 2 is larger than that of material powder A, is used, and the combination of central particle sizes of the material powders is changed so that the standard deviation of the perimeter length of the void portion of the support cross-section is less than 400. In this example, the supports become less likely to break, so it was necessary to increase the injection pressure to remove the supports, which caused some damage to the fine details, but this was within a range that did not pose a practical problem.

[0109] [Example 16] In Example 16, the laser scanning interval of the support section was changed, and the perimeter of the void in the support cross section was 100 μm / mm. 2 This is an example where the proportion of the above-mentioned elements was less than 25%. In this example, brittle fracture was less likely to occur than in Example 1, and it was necessary to increase the injection pressure to remove the supports. As a result, some damage occurred to the fine details, but it was within a range that did not pose a practical problem.

[0110] [Example 17] Example 17 is an example where the output of the laser beam used for support fabrication is lower than the output of the laser beam used for main fabrication. In this example, the supports are less likely to break compared to Example 1, so it was necessary to increase the spray pressure to remove the supports. As a result, some minor damage occurred to the fine details, but this was within a range that did not pose a practical problem.

[0111] [Example 18] Example 18 uses material powder F, in which the central particle size of raw material 1 is smaller than that of material powder C, resulting in a perimeter of the voids in the support cross-section of 100 μm / mm. 2The proportion of the above-mentioned elements is less than 25%. In addition, the molding conditions for the support section were changed, and the sum of the perimeter lengths of the voids obtained by observing the cross-section of the support is smaller than in Example 3. Furthermore, alumina with a higher Young's modulus than in Example 3 was used as the media, and the difference in Young's modulus between the support and the media is less than 30 [GPa]. The central particle size of the media is 4 mm. In this example, brittle fracture was less likely to occur than with the support in Example 1, and it was necessary to increase the injection pressure to remove the support, which resulted in some damage to the fine details. Also, because the difference in Young's modulus between the main body and the media is less than 30 [GPa], the main body was slightly abraded and some damage was observed. In addition, because the central particle size of the media is larger than in Example 1, supports in small holes could not be removed, but supports in 1 mm holes could be removed. Although some damage was observed, it was all within a range that did not pose a practical problem.

[0112] [Example 19] Example 19 is the same as Example 1 except that the media shape is crushed. The circularity of the media in this example was 0.75. In this example, the crushed shape of the media resulted in a higher cutting force compared to Example 1, and damage to the main body was observed during blasting, but it was within a range that did not pose a practical problem.

[0113] [Example 20] Example 20 is an example in which glass was used as the media. The circularity of the media in this example was 0.97. In this example, because the media did not have an elastic structure, some damage occurred to the fine details, but it was within a range that did not cause any practical problems.

[0114] [Example 21] Example 21 is an example in which crushed glass was used as the media. The circularity of the media in this example was 0.73. In this example, because the media did not have an elastic structure, some damage occurred to the fine details, but it was within a range that did not cause practical problems. In addition, in this example, the crushed shape of the media increased the cutting force, and damage was observed to the main body as it was cut during blasting, but it was within a range that did not cause practical problems.

[0115] <Comparative Examples 1-8> Except for the material powder, molding conditions, and blasting conditions shown in Table 6, the molded objects were formed and evaluated in the same manner as in the examples. The evaluation results are shown in Table 6. Problems occurred in all cases, and the evaluation results were NG. Note that in Table 6, a negative value for the difference in Young's modulus indicates that the Young's modulus of the media is higher than that of the main body.

[0116] [Table 6]

[0117] [Comparative Example 1] In this comparative example, the same material powder A as in Example 1 was used as the material powder, and the molding conditions were also the same as in Example 1. In addition, in this comparative example, silicon carbide with a central particle size of 0.2 mm was used as the media. As can be seen from Table 5, in this comparative example, the Young's modulus of the media is higher than that of the main body.

[0118] In this comparative example, because the Young's modulus of the media was higher than that of the main body, damage to the main body and micro-areas occurred during blasting. Furthermore, the ability to remove micro-area supports could not be evaluated because the surrounding main body was damaged.

[0119] [Comparative Example 2] In this comparative example, the same material powder B as in Example 2 was used as the material powder, and the molding conditions were also the same as in Example 2. In addition, in this comparative example, stainless steel with a media size of 0.2 mm was used as the media. As can be seen from Table 5, in this comparative example as well, the Young's modulus of the media is higher than that of the main body.

[0120] In this comparative example, because the Young's modulus of the media was higher than that of the main body, damage to the main body and micro-areas occurred during blasting. Furthermore, the ability to remove micro-area supports could not be evaluated because the surrounding main body was damaged.

[0121] [Comparative Example 3] In this comparative example, a metal powder (SUS630) with a median particle size of 18 μm was used as the material powder. In addition, a nylon media with a median particle size of 0.2 mm was used in this comparative example.

[0122] In this comparative example, because metal powder was used as the material powder, the support underwent plastic deformation, and even with the maximum blast pressure, the support could not be destroyed during blasting, making evaluation impossible.

[0123] [Comparative Example 4] In this comparative example, the same material powder A as in Example 1 was used as the material powder, and the molding conditions and media for the main body were the same as in Example 1. In this comparative example, only the main body was molded, without the creation of support structures.

[0124] In this comparative example, the support structure was not fabricated, causing the main body to break during the fabrication process, making evaluation impossible.

[0125] [Comparative Example 5] In this comparative example, the same material powder A as in Example 1 was used as the material powder, and the molding conditions for the main body and support parts were the same as in Example 1. In this comparative example, the support parts were removed using a rotary tool instead of blasting.

[0126] In this comparative example, the support was removed using a rotary tool, and the main body was damaged when the rotary tool accidentally touched the main body.

[0127] [Comparative Example 6] In this comparative example, a lattice shape made of thin columns was used as support. Here, the fabrication conditions for the lattice shape support were the same as for the main body. In this comparative example, the support portion was removed using a rotary tool instead of sandblasting.

[0128] In this comparative example, the support was removed using a rotary tool, and the main body was damaged when the rotary tool accidentally touched the main body.

[0129] [Comparative Example 7] In this comparative example, metal powder (aluminum) was used as the material powder, and the molding conditions were the same as in Comparative Example 3. In addition, in this comparative example, a SUS304 material with a central particle size of 0.2 mm was used as the media.

[0130] In this comparative example, because the Young's modulus of the media was higher than that of the main body, damage to the main body and micro-areas occurred during blasting. Furthermore, the ability to remove micro-area supports could not be evaluated because the surrounding main body was damaged.

[0131] [Comparative Example 8] In this comparative example, the same metal powder (SUS630) as in Comparative Example 3 was used as the material powder, and the molding conditions were also the same as in Comparative Example 3. In addition, in this comparative example, an aluminum media with a central particle size of 0.2 mm was used.

[0132] In this comparative example, because metal powder was used as the material powder, the supports underwent plastic deformation and brittle fracture did not occur, making it impossible to remove the supports without increasing the blast pressure. Due to the high blast pressure, damage occurred to the main body and the fine details. Furthermore, the ability to remove supports from the fine details could not be evaluated because the surrounding main body was damaged.

[0133] ≪Included components≫ This embodiment includes the following configuration. (Composition 1) A layered fabrication process for layering a layered object having a first part and a second part located near the first part, using ceramic powder. A removal step of removing the second part of the additively manufactured object while leaving the first part intact by blasting the additively manufactured object with media, It has, A method for manufacturing a three-dimensional object, characterized in that the Young's modulus of the media is lower than the Young's modulus of the first portion.

[0134] (Configuration 2) A method for manufacturing a three-dimensional object according to configuration 1, characterized in that the difference between the Young's modulus of the media and the Young's modulus of the first portion is 30 [GPa] or more. (Composition 3) A method for manufacturing a three-dimensional object according to configuration 1 or 2, characterized in that the Young's modulus of the media is 20 [GPa] or less. (Composition 4) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 3, characterized in that the Young's modulus of the first portion is 50 [GPa] or more. (Composition 5) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 4, characterized in that the media is made of a resin material. (Composition 6) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 5, characterized in that the central particle size of the media is 3 mm or less. (Composition 7) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 6, characterized in that the circularity of the media is 0.75 or more and 1 or less.

[0135] (Composition 8) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 7, characterized in that the sum of the perimeters of the voids in the cross-section of the second portion is greater than the sum of the perimeters of the voids in the cross-section of the first portion. (Composition 9) The sum of the perimeter lengths of the voids in the cross-section of the second portion is 7000 μm / mm 2 A method for manufacturing a three-dimensional object according to any one of configurations 1 to 8, characterized in that it is as described above. (Composition 10) The sum of the perimeter lengths of the voids in the cross-section of the second portion is 2000 μm / mm² greater than the sum of the perimeter lengths of the voids in the cross-section of the first portion. 2 A method for manufacturing a three-dimensional object according to any one of the configurations 1 to 9, characterized in that it is larger than the above. (Composition 11) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 10, characterized in that the standard deviation of the perimeter of the void portion in the cross-section of the second portion is 400 or more. (Composition 12) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 11, characterized in that the proportion of the perimeter of the void portion in the cross-section of the second portion that has a perimeter of 100 μm or more is 25% or more.

[0136] (Composition 13) The aforementioned additive manufacturing process is, A placement process for arranging ceramic powder, A step of irradiating the ceramic powder with laser light to form the first portion, A step of irradiating the ceramic powder with laser light to form the second portion, A method for manufacturing a three-dimensional object according to any one of configurations 1 to 12, characterized by having the above. (Composition 14) A method for manufacturing a three-dimensional object according to configuration 13, characterized in that the conditions for irradiating the laser light in the step of forming the first part are different from the conditions for irradiating the laser light in the step of forming the second part. (Composition 15) A method for manufacturing a three-dimensional object according to configuration 14, characterized in that the output of the laser light in the step of forming the second part is higher than the output of the laser light in the step of forming the first part, and the scanning speed of the laser light in the step of forming the second part is faster than the scanning speed of the laser light in the step of forming the first part. (Composition 16) A method for manufacturing a three-dimensional object according to configuration 13, characterized in that the ceramic powder forming the first part and the ceramic powder forming the second part are the same. (Composition 17) Furthermore, the method for manufacturing a three-dimensional object according to any one of configurations 1 to 16, comprising the steps of preparing shape data for the first part and preparing shape data for the second part. (Composition 18) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 17, characterized in that, after the removal step, it comprises a firing step of firing the first portion. (Composition 19) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 18, characterized in that the Young's modulus of the media is lower than the Young's modulus of the second portion. (Composition 20) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 19, characterized in that the first part is the main body and the second part is a support. (Composition 21) A method for manufacturing a three-dimensional object according to any one of configurations 1 to 20, characterized in that the ceramic powder is a mixed powder of multiple ceramic powders with different central particle sizes.

[0137] (Composition 22) A container containing ceramic powder, The container includes a medium for blast processing of an object formed using the aforementioned ceramic powder, The product is characterized in that the Young's modulus of the media is lower than that of the ceramic particles in the ceramic powder. (Composition 23) The product according to configuration 22, characterized in that the media is made of a resin material. (Composition 24) The product according to configuration 22 or 23, characterized in that it includes a document describing the molding conditions in the aforementioned molding process. [Explanation of symbols]

[0138] 1: Main body (first part), 2: Support (second part), 3: Build stage, 11: Thin plate, 12: Hole, 71: Stage, 72: Drive unit, 73: Nozzle, 100: Solidification unit, 101: Powder, 102: Powder layer, 103: Unsolidified powder, 110: Three-dimensional object, 130: Base, 151: Stage, 152: Roller, 180: Laser light source, 181: Scanner unit

Claims

1. A layered fabrication process for layering a layered object having a first part and a second part located near the first part, using ceramic powder. A removal step of removing the second part of the additively manufactured object while leaving the first part intact by blasting the additively manufactured object with a media, It has, A method for manufacturing a three-dimensional object, characterized in that the Young's modulus of the media is lower than the Young's modulus of the first portion.

2. The method for manufacturing a three-dimensional object according to claim 1, characterized in that the difference between the Young's modulus of the media and the Young's modulus of the first portion is 30 [GPa] or more.

3. The method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the Young's modulus of the media is 20 [GPa] or less.

4. A method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the Young's modulus of the first portion is 50 [GPa] or more.

5. The method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the media is made of a resin material.

6. The method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the central particle size of the media is 3 mm or less.

7. A method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the circularity of the media is 0.75 or more and 1 or less.

8. A method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the sum of the perimeters of the voids in the cross-section of the second portion is greater than the sum of the perimeters of the voids in the cross-section of the first portion.

9. The sum of the perimeter lengths of the voids in the cross-section of the second portion is 7000 μm / mm 2 The method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that it is as described above.

10. The sum of the perimeter lengths of the voids in the cross-section of the second portion is 2000 μm / mm greater than the sum of the perimeter lengths of the voids in the cross-section of the first portion. 2 A method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that it is larger than the above.

11. The method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the standard deviation of the perimeter of the void portion in the cross-section of the second portion is 400 or more.

12. A method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the proportion of the perimeter of the void portion in the cross-section of the second portion that has a perimeter of 100 μm or more is 25% or more.

13. The aforementioned additive manufacturing process is, A placement process for arranging ceramic powder, A step of irradiating the ceramic powder with laser light to form the first portion, A step of irradiating the ceramic powder with laser light to form the second portion, A method for manufacturing a three-dimensional object according to claim 1 or 2, characterized by having the following:

14. The method for manufacturing a three-dimensional object according to claim 13, characterized in that the conditions for irradiating the laser light in the step of forming the first part are different from the conditions for irradiating the laser light in the step of forming the second part.

15. The method for manufacturing a three-dimensional object according to claim 14, characterized in that the output of the laser light in the step of forming the second part is higher than the output of the laser light in the step of forming the first part, and the scanning speed of the laser light in the step of forming the second part is faster than the scanning speed of the laser light in the step of forming the first part.

16. The method for manufacturing a three-dimensional object according to claim 13, characterized in that the ceramic powder forming the first portion and the ceramic powder forming the second portion are the same.

17. Furthermore, the method for manufacturing a three-dimensional object according to claim 1 or 2, further comprising the steps of preparing shape data for the first part and preparing shape data for the second part.

18. A method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that, after the removal step, the method further comprises a firing step of firing the first portion.

19. The method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the Young's modulus of the media is lower than that of the second portion.

20. A method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the first part is the main body and the second part is a support.

21. The method for manufacturing a three-dimensional object according to claim 1 or 2, characterized in that the ceramic powder is a mixed powder of multiple ceramic powders having different central particle sizes.

22. A container containing ceramic powder, The container includes a medium for blast processing of an object formed using the aforementioned ceramic powder, The product is characterized in that the Young's modulus of the media is lower than that of the ceramic particles in the ceramic powder.

23. The product according to claim 22, characterized in that the media is made of a resin material.

24. The product according to claim 22 or 23, characterized in that it includes a document describing the molding conditions in the aforementioned molding process.

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