Additive manufacturing system and additive manufacturing method

Abstract

The invention provides an additive manufacturing system and an additive manufacturing method. The additive manufacturing system includes: a frame; the base plate is arranged in the frame; the forming cavity is limited by the frame and the base plate; and a powder laying device configured to lay a powder material on the substrate so as to perform additive manufacturing on the substrate. Wherein the substrate comprises at least two supporting parts, and the supporting parts can move relative to each other. According to the additive manufacturing system and the additive manufacturing method of the present application, the use amount of the powder material is reduced by selectively moving or not moving the support part according to the shape of the workpiece to be processed, i.e., the utilization rate of the powder material is improved, thereby significantly reducing the cost.

Description

Technical Field

[0001] The present application relates to the technical field of additive manufacturing, and in particular, to an additive manufacturing system and an additive manufacturing method for performing additive manufacturing by melting and depositing materials layer by layer. Background Art

[0002] Additive layer manufacturing (ALM) technology is a technology that first uses a computer to design a product and then prints it out with a printer. In computer design, the product to be formed is modeled, the model is divided into many 2D layers, and the design data of each layer is stored in the computer for subsequent printing. During the printing process, the material is accumulated and printed (i.e., melted and deposited) layer by layer using a heat source (e.g., a laser beam, electron beam, plasma or ion beam) until the final 3D product is formed. Additive manufacturing is also commonly referred to as 3D printing. Additive manufacturing is particularly suitable for the manufacture of metal parts with complex shapes or special structures in the aerospace industry, for example.

[0003] An additive manufacturing system for additive manufacturing of powder materials is known, comprising a molding chamber, a powder spreading device, a substrate and a heat source. The molding chamber provides space for additively manufactured workpieces. The substrate is arranged in the molding chamber and has a flat surface for supporting powder materials or processed parts. When additive manufacturing starts, the substrate is moved downward to a required height according to the thickness of the first layer to be processed of the workpiece, the powder spreading device spreads the powder material on almost the entire substrate, and the heat source heats the powder material at a specific position according to the data of the first layer of the workpiece, melts it and solidifies it to form the first layer structure of the workpiece. Then, the substrate is moved downward to a required height according to the thickness of the second layer to be processed of the workpiece, and the same manufacturing steps as the first layer are repeated until the structure of the last layer of the workpiece is formed. Thus, the entire workpiece is processed. Summary of the invention

[0004] Technical issues

[0005] The above-mentioned existing additive manufacturing system includes an integral or single substrate having a flat surface for supporting powder material or processing a workpiece. When the structure of the last layer of the workpiece is formed, the total volume (i.e., the total amount) of the raw material (i.e., powder material) used for additive manufacturing roughly corresponds to the volume of the space defined by the height of the substrate and the workpiece of the forming cavity, including the volume (corresponding to the volume of the workpiece) of the material consumed for forming the workpiece (hereinafter referred to as the consumed material) and the powder material not used to form the workpiece (hereinafter referred to as the unconsumed material). The utilization rate of the raw material is equal to the volume of the consumed material divided by the total volume of the raw material.

[0006] However, workpieces generally have complex external shapes, such as curved surfaces, concave and convex parts, holes or channels, etc. The complex external shapes increase the amount of unconsumed materials to a certain extent, thereby reducing the utilization rate of raw materials. Even if the unconsumed materials can be recovered and reused to manufacture the next workpiece, the number of times the materials can be reused is limited. In other words, after the material has been reused a predetermined number of times, even the unconsumed materials can no longer be used to form the workpiece.

[0007] Therefore, it is desirable to improve the utilization rate of raw materials, thereby reducing the waste of raw materials and saving costs.

[0008] In view of the above problems, the present application proposes an additive manufacturing solution, which can change the shape of the molding cavity according to the outer shape of the workpiece to be processed to reduce the total volume of the raw material, thereby improving the utilization rate of the raw material and thus significantly reducing the cost.

[0009] Technical Solution

[0010] According to one aspect of the present disclosure, an additive manufacturing system is provided. The additive manufacturing system comprises: a frame; a substrate, the substrate being arranged in the frame; a molding cavity, the molding cavity being defined by the frame and the substrate; and a powder spreading device, the powder spreading device being configured to spread powder material on the substrate so as to perform additive manufacturing on the substrate, wherein the substrate comprises at least two supporting parts, and the supporting parts are movable relative to each other.

[0011] In some examples of additive manufacturing systems, the at least two support portions of the base plate are arranged in a nested manner.

[0012] In some examples of the additive manufacturing system, the at least two supports are arranged in a side-by-side manner.

[0013] In some examples of the additive manufacturing system, the additive manufacturing system further includes at least two driving devices for independently driving the at least two supporting parts respectively.

[0014] In some examples of the additive manufacturing system, the base plate is configured such that the support portion can move in a direction opposite to a forming direction of the workpiece.

[0015] In some examples of the additive manufacturing system, the additive manufacturing system further includes a heat source configured to print the powder material in a predetermined scanning path according to layer design parameters of the workpiece model after powder laying is completed.

[0016] According to another aspect of the present disclosure, an additive manufacturing method for manufacturing a workpiece using the additive manufacturing system is provided. The additive manufacturing method comprises: selectively moving or not moving each support portion of the substrate based on the outer shape of the workpiece; laying powder material on the substrate by the powder laying device; and printing the powder material on the substrate with a predetermined scanning path based on the layer design parameters of the workpiece model.

[0017] In some examples of the additive manufacturing method, in the step of selectively moving the support portions, a support portion corresponding to a recessed portion of the workpiece is not moved, while other support portions are moved.

[0018] In some examples of the additive manufacturing method, the additive manufacturing method further includes: repeatedly performing the step of moving the support portion, the step of spreading powder, and the step of printing until the workpiece is manufactured.

[0019] In some examples of the additive manufacturing method, the additive manufacturing method further includes: modeling the workpiece to obtain layer design parameters of the workpiece model, wherein the workpiece model is positioned such that an outer surface having the recessed portion is adjacent to and faces the substrate.

[0020] Technical Effects

[0021] According to the additive manufacturing system and method of the present application, the support portion of the substrate can be selectively moved or not moved, and the shape of the molding cavity can be made to conform to the outer shape of the workpiece as much as possible through the relative movement between the support portions. In this way, the amount of powder material used can be reduced, and thus the cost can be significantly reduced.

[0022] Other advantages and features of the invention will become apparent in the following non-limiting detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The features and advantages of one or more embodiments of the present invention will become more easily understood through the following description with reference to the accompanying drawings, in which:

[0024] Figure 1 is a cross-sectional schematic diagram of an additive manufacturing system according to an embodiment of the present application;

[0025] FIG. 2A to FIG. 2C is used Figure 1 A schematic cross-sectional view of various processing stages of additive manufacturing performed by an additive manufacturing system shown;

[0026] Figure 3 is a schematic top view of a substrate according to an embodiment of the present application;

[0027] Figure 4 is a schematic top view of a substrate according to another embodiment of the present application; and

[0028] Figure 5 is a flow chart of an additive manufacturing method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and by means of exemplary embodiments. The following detailed description of the present invention is for illustrative purposes only and is by no means intended to limit the present invention and its application or use. In all drawings, corresponding reference numerals indicate corresponding parts.

[0030] Exemplary embodiments are provided herein so that the present disclosure will be thorough and will fully convey the scope to those skilled in the art. Many specific details such as examples of specific components, devices and methods are set forth to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be adopted, and exemplary embodiments can be implemented in many different forms and should not be construed as limiting the scope of the present disclosure. In some exemplary embodiments, known methods, known device structures and known technologies are no longer described in detail.

[0031] Although the terms first, second, third, etc. can be used in this article to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another element, component, region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not mean order or sequence when used in this article. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.

[0032] The directional words mentioned in this document, such as “upper, lower, left, right”, refer to the directions observed on the drawings for the purpose of description, and are not intended to limit the present invention, unless otherwise explicitly stated herein.

[0033] The following will refer to Figure 1 An additive manufacturing system 10 having a deformable molding cavity according to an embodiment of the present application is described. Figure 1 is a schematic diagram of an additive manufacturing system according to the present application. It should be understood that Figure 1 The additive manufacturing system 10 schematically shown in FIG. 1 is for illustrative purposes only and is not intended to limit the specific structure of the additive manufacturing system according to the present application.

[0034] See also Figure 1The additive manufacturing system 10 includes a frame 101, a powder material supply mechanism 11, a powder spreading device 13, a molding cavity 15, a substrate 17 and a heat source 19.

[0035] The frame 101 is a fixed basic structural component used to form, support, and install other parts of the additive manufacturing system 10. The structure of the frame 101 can be changed as needed, so it will not be described in detail herein.

[0036] The powder material supply mechanism 11 is configured to supply the powder material PM to the powder spreading device 13 or the molding cavity 15 so as to heat, melt, and solidify the powder material to form the workpiece 12. The powder material supply mechanism 11 may include a storage bin 111 for storing the powder material PM and a supply device 113 for supplying the powder material PM toward the powder spreading device 13 or the molding cavity 15. Figure 1 In the example shown, the supply device 113 is in the form of a piston rod and defines a storage bin 111 together with the frame 101. When powder material needs to be supplied, the supply device 113 moves along the piston rod. Figure 1 It should be understood that the configuration of the powder material supply mechanism 11 should not be limited to Figure 1 The specific examples shown in the text may be changed as long as the functions described in the text can be achieved.

[0037] The powder spreading device 13 is configured to evenly spread the powder material supplied by the powder material supply mechanism 11 on the substrate 17. The powder spreading device 13 may include a scraper 131. The length of the scraper 131 may be determined based on the size of the substrate. The scraper 131 may move in a substantially horizontal direction, first from one end ( Figure 1 The left end of the substrate 17 moves in the direction indicated by arrow B to the other end ( Figure 1 and then from the other end of the substrate 17 ( Figure 1 The right end in the middle) returns to one end of the substrate 17 ( Figure 1 ), thereby completing a powder spreading cycle, thereby spreading the powder PM into the molding cavity 15 so that the powder PM is flush with the edge of the molding cavity 15.

[0038] After one or more powder laying cycles until the predetermined laying thickness of the powder material is reached, the heat source 19 heats the powder material according to the structure or design parameters of the corresponding layer of the workpiece 12, causing the powder material to melt and then solidify to form the layer of the workpiece 12. Figure 1 In the example of FIG. 1 , the heat source 19 includes a laser 191 for emitting a laser beam and a light shaping device 193 for shaping the laser beam. The laser beam shaped by the light shaping device 193 has the desired light characteristics, spot size or shape, etc. However, it should be understood that the heat source should not be limited to Figure 1 The specific examples shown in the drawings may be changed as long as the functions described in this document can be achieved. For example, the heat source may be a heat source that generates an electron beam, plasma, or ion beam.

[0039] The position of the powder spreading device 13 in the vertical direction can be basically unchanged. After a layer of the workpiece 12 is formed, the substrate 17 can be moved along Figure 1 The vertical direction shown by the arrow C in FIG. 1 is decreased, for example, by a height corresponding to the required material laying thickness. Then, the powder spreading device 13 starts spreading powder, and the above-mentioned forming process is repeated to form the next layer of the workpiece 12.

[0040] It should be understood that the configuration of the powder spreading device 13 should not be limited to the specific examples described above or shown in the figures, but can be changed as long as it can achieve the functions described herein. For example, the position of the powder spreading device 13 (or its scraper 131) in the vertical direction can be changed.

[0041] The molding cavity 15 is configured to provide a space for molding the workpiece 12. Figure 1 The molding cavity 15 is defined by the frame 101 and the substrate 17. The substrate 17 is movable relative to the frame 101. As the workpiece 12 is molded layer by layer, the substrate 17 moves downward in the direction of arrow C. The workpiece 12 is manufactured layer by layer in the upward direction indicated by arrow D. Accordingly, the size of the molding cavity 15 gradually increases, and the powder material filled therein gradually increases.

[0042] The material in the molding cavity 15 includes two parts, namely, a first part M1 (also called "effectively utilized part") consumed to form the workpiece 12 and an unused second part M2. The second part M2 is still basically in powder form, just like the state of the material PM in the storage bin 111.

[0043] The substrate 17 is configured to carry or support the powder material and the workpiece 12. The forming process of forming the workpiece 12 from the powder material is performed on the substrate 17, so the substrate 17 can also be called a "forming platform". In this embodiment, the substrate 17 includes a first support portion 171 and a second support portion 172. The first support portion 171 and the second support portion 172 can both move in a vertical direction relative to the frame 101. The first support portion 171 and the second support portion 172 can also move relative to each other.

[0044] To this end, the additive manufacturing system 10 may also include a first drive device 175 for moving the first support portion 171 and a second drive device 176 for moving the second support portion 172. In this way, the first support portion 171 and the second support portion 172 can be controlled and moved independently of each other. The first drive device 175 can be, for example, a mechanical drive device such as a screw, an electric drive device including a motor, an electromagnetic drive device including a magnet and a coil, a hydraulic drive device, or a pneumatic drive device. Similarly, the second drive device 176 can be, for example, a mechanical drive device, an electric drive device, an electromagnetic drive device, a hydraulic drive device, or a pneumatic drive device. In other words, the configuration of the first drive device 175 and the second drive device 176 should not be limited as long as they can achieve the functions described herein.

[0045] The workpiece 12 is merely an example of a workpiece having a complex outer shape such as a curved surface, a concave-convex structure, a hole or a channel, and is used to describe how the shape of the molding cavity 15 according to the present application changes according to the shape of the workpiece 12 (described in detail below). Figure 1 In the example of FIG. 1 , the workpiece 12 has a generally cylindrical body 121, at one end ( Figure 1 The lower end of the convex part 120 has a concave curved surface 122. The curved surface 122 defines a concave portion 125. It should be understood that the workpiece suitable for being manufactured by the additive manufacturing system according to the present application should not be limited to the specific examples shown in the figures.

[0046] The following will refer to FIG. 2A to FIG. 2C To describe the use of the additive manufacturing system 10 according to the present application to manufacture such Figure 1 The manufacturing process of the workpiece 12 is shown. Figure 2A A stage for forming a first layer L1 of a workpiece 12 is shown; Figure 2B shows a stage for forming an nth layer Ln of a workpiece 12; Figure 2C A stage for forming the last layer L0 of the workpiece 12 , ie, a stage for forming the entire workpiece 12 , is shown.

[0047] Reference Figure 2A When the workpiece 12 is to be manufactured, that is, when the first layer L1 of the workpiece 12 is to be formed, the second support portion 172 of the substrate 17 is driven by the second drive device 176 to move downward relative to the frame 101. The distance the second support portion 172 moves downward corresponds to the thickness of the first layer L1 of the workpiece 12. The first support portion 171 does not move, for example, and remains with the frame 101. Figure 1 The scraper 131 is shown aligned.

[0048] After the second support 172 is moved into position, the powder spreading device 13 spreads powder on the substrate 17. Since the first support 171 does not move (i.e., is aligned with the scraper 131), the powder material is basically spread on the second support 172. There is almost no powder material on the first support 171, or there is very little powder material. After the powder spreading is completed, the heat source 19 is turned on to start forming the first layer L1 of the workpiece 12. Repeat the above steps, and then form the second layer (not shown) of the workpiece 12.

[0049] Reference Figure 2B When the nth layer Ln of the workpiece 12 is to be formed, in addition to the second support 172, it is also necessary to lay powder material on the first support 171 and form a part of the workpiece 12. Therefore, the first support 171 and the second support 172 move downward together by a certain distance. The powder laying process and the forming process are the same as those mentioned above. Figure 1 The powder spreading process described is the same as the molding process, so it will not be described in detail. After the n-th layer Ln of the workpiece 12 is formed, the curved surface 122 of the workpiece 12 has been manufactured.

[0050] Thereafter, the first support portion 171 and the second support portion 172 are moved downward together to form the cylindrical portion of the workpiece 12 until the last layer L0 of the entire workpiece 12 is manufactured. Figure 2C See Figure 2C Combined with Figure 1 , the top surface 171a of the first support portion 171 protrudes a certain distance relative to the top surface 172a of the second support portion 172 and extends into the recessed portion 125 of the workpiece 12. Since the top of the first support portion 171 occupies most of the space of the recessed portion 125 of the workpiece 12, the powder material filled in the recessed portion 125 is significantly reduced compared with the existing additive manufacturing system with a monolithic substrate. In the existing additive manufacturing system with a monolithic substrate, the substrate has a flat supporting surface, so the entire recessed portion 125 of the workpiece 12 is filled with powder material.

[0051] From the above content, it can be known that through the relative movement between the first support part 171 and the second support part 172, the shape of the molding cavity 15 can be changed so that the shape of the molding cavity 15 conforms to the external shape of at least a part of the workpiece 12 as much as possible, thereby reducing the total amount of powder material filled into the molding cavity 15.

[0052] The present application proposes a molding cavity for an additive manufacturing system or device, the shape of which can be changed according to the shape of the workpiece during the workpiece molding process, thereby reducing the total volume of the raw material, thereby improving the utilization rate of the raw material, and thus significantly reducing the cost. The additive manufacturing device or system with a deformable molding cavity is suitable for manufacturing workpieces with complex shapes such as curved surfaces, concave-convex structures, holes or channels.

[0053] The "total volume of raw materials" and "utilization rate of raw materials" mentioned here refer to the total volume and utilization rate of powder materials laid in the molding cavity by the powder laying device during the entire additive manufacturing process of a certain workpiece. The "shape of the molding cavity" mentioned here refers to the shape that can affect the total volume and utilization rate of the raw materials, in particular, the shape of the surface in contact with the raw materials.

[0054] The shape of the molding cavity according to the present application can be changed by changing the shape of the supporting surface of the substrate. In this case, in the molding design, the outer surface of the workpiece to be processed with a complex shape such as a curved surface, a concave-convex structure, a hole or a channel can be positioned adjacent to or facing the supporting surface of the substrate.

[0055] The substrate can be provided in a split type, including at least two supporting parts that can move relative to each other. When one of the supporting parts moves relative to the other supporting parts, the shape of the surface of the substrate used to support the raw material and manufacture the workpiece is changed. Preferably, one of the supporting parts can move relative to the other supporting parts in a direction opposite to the forming direction of the workpiece. The supporting part that rises relative to the other supporting parts can be filled in the concave part of the workpiece. Compared with the solution in the prior art in which the concave part is completely filled with raw materials, the present invention omits the amount of raw materials corresponding to the filling part of the supporting part. As a result, the utilization rate of the raw materials is significantly improved.

[0056] It should be understood that the configuration of the substrate 17 should not be limited to the specific example shown in the figure, as long as a part of it can be moved relative to other parts to fill the concave portion on the outer surface of the workpiece. The substrate 17 can be designed or arranged according to the external shape of the workpiece to be manufactured. The substrate 17 can be installed in a replaceable manner, so that when it is necessary to process a workpiece with a different shape, the substrate 17 with a different structure can be replaced accordingly.

[0057] Figure 3 is a schematic top view of a substrate 200 according to another embodiment of the present application. Figure 3The substrate 200 shown includes a first support portion 201, a second support portion 202, a third support portion 203 and a fourth support portion 204. The first support portion 201, the second support portion 202, the third support portion 203 and the fourth support portion 204 are arranged in a nested manner. Specifically, the first support portion 201 has a rectangular or square cross-section, the second support portion 202 is annular and is located outside the first support portion 201, the third support portion 203 is annular and is located outside the second support portion 202, and the fourth support portion 204 is annular and is located outside the third support portion 203. The substrate 200 is configured so that each support portion can move relative to each other, but the powder material will not fall between each support portion. The substrate 200 is suitable for manufacturing a workpiece having, for example, a central concave portion or an annular concave portion.

[0058] Figure 4 It is a schematic top view of a substrate 300 according to yet another embodiment of the present application. Figure 4 The substrate 300 shown includes a first support portion 301, a second support portion 302 and a third support portion 303. The first support portion 301, the second support portion 302 and the third support portion 303 are arranged in a side-by-side manner. The substrate 300 is configured so that each support portion can move relative to each other, but the powder material will not fall between the support portions. The substrate 300 is suitable for manufacturing a workpiece having a step portion, for example.

[0059] Figure 3 and Figure 4 Different arrangements of the substrate are shown. However, it should be understood that the number or arrangement of the support parts of the substrate, the shape or size of each support part, etc. can be changed according to the shape of the workpiece to be processed, and should not be limited to the specific examples described herein or shown in the figures. For example, multiple support parts can be combined to adopt nested and side-by-side arrangements. In addition, each support part can have the same shape or size, or different shapes or sizes.

[0060] Next, we will refer to Figure 5 The additive manufacturing method S0 according to an embodiment of the present disclosure is described. Figure 5 is a flow chart of an additive manufacturing method S0 according to an embodiment of the present disclosure.

[0061] See also Figure 5 In step S11, first, the various supporting parts of the substrate 17 are selectively moved or not moved according to the outer shape of the workpiece 12 (especially the outer shape adjacent to and facing the substrate). In step S11, if a supporting part corresponds to the concave part 125 of the workpiece 12, the supporting part can be not moved, while the other supporting parts are moved. Figure 2A As shown, the first supporting portion 171 is not moved, but the second supporting portion 172 is moved downward.

[0062] When the support part is moved into position, the powder material is spread on the substrate by the powder spreading device 13 (see step S12). In step S12, the powder spreading device 13 usually moves back and forth in a direction perpendicular to the forming direction of the workpiece. Figure 1 As shown, the workpiece forming direction is vertical, and the powder spreading device 13 reciprocates in the horizontal direction.

[0063] After the powdering is completed, proceed to step S13. In step S13, the powder material on the substrate is printed with a predetermined scanning path based on the layer design parameters of the workpiece model by the heat source 19. The printing described herein refers to the process of heating the powder, melting the powder material until it solidifies to form a layer structure of the workpiece.

[0064] The above steps S11 to S13 may be repeatedly performed until the entire workpiece is formed, that is, the workpiece is manufactured (step S14).

[0065] As can be seen from the above description, it is advantageous to make the surface of the workpiece having a complex outer shape (especially, the outer surface having a concave portion) adjacent to and facing the substrate, such as Figures 1 to 2C Therefore, when the workpiece is modeled using a computer, the model of the workpiece can be positioned so that its outer surface having the recessed portion is adjacent to and faces the substrate, thereby obtaining layer data (or layer design parameters) of the workpiece model.

[0066] It should be understood that the additive manufacturing method according to the present disclosure should not be limited to the specific examples described herein or shown in the drawings, but can be changed. For example, steps can be added, steps can be omitted, the order of each step can be changed, etc. according to actual needs.

[0067] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the specific embodiments / examples described and shown in detail herein, and that various changes may be made to the exemplary embodiments by those skilled in the art without departing from the scope defined by the claims.

Claims

1. An additive manufacturing system, comprising: frame; a substrate, the substrate being arranged in the frame; a molding cavity defined by the frame and the substrate; as well as a powder spreading device, the powder spreading device being configured to spread powder material on the substrate so as to perform additive manufacturing on the substrate, Wherein, the base plate comprises at least two supporting parts, and the supporting parts are movable relative to each other.

2. The additive manufacturing system of claim 1, wherein: The at least two supporting portions of the base plate are arranged in a nested manner.

3. The additive manufacturing system according to claim 1, wherein: The at least two supporting parts are arranged side by side.

4. The additive manufacturing system according to claim 1, further comprising at least two driving devices for independently driving the at least two supporting parts respectively.

5. The additive manufacturing system according to claim 1, wherein: The base plate is configured such that the support portion is movable in a direction opposite to a molding direction of the workpiece.

6. The additive manufacturing system according to any one of claims 1 to 5, wherein: The additive manufacturing system further includes a heat source, which is configured to print the powder material in a predetermined scanning path according to the layer design parameters of the workpiece model after the powder laying is completed.

7. An additive manufacturing method for manufacturing a workpiece using the additive manufacturing system according to any one of claims 1 to 6, comprising the following steps: selectively moving or not moving each support portion of the substrate based on the outer shape of the workpiece; The powder spreading device spreads powder material on the substrate; as well as The powder material on the substrate is printed in a predetermined scanning path based on the layer design parameters of the workpiece model.

8. The additive manufacturing method according to claim 7, wherein: In the step of selectively moving the supporting portions, the supporting portions corresponding to the recessed portions of the workpiece are not moved, and the other supporting portions are moved.

9. The additive manufacturing method according to claim 7, further comprising: The steps of moving the support portion, spreading powder and printing are repeated until the workpiece is manufactured.

10. The additive manufacturing method according to any one of claims 7 to 9, further comprising: The workpiece is modeled to obtain layer design parameters of the workpiece model, wherein the workpiece model is positioned such that an outer surface having the recessed portion is adjacent to and faces the substrate.

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