Systems and methods for building large single crystal objects using segmented scanning patterns

Abstract

The segmented scan pattern yields a 3D printed metal object having a large scale cubic crystal structure. A first patterned layer is produced by moving a molten pool in the first powder layer along a first layer scan pattern that includes a first layer first section, a first layer second section, and a first layer first lap at which the first layer first section and the first layer second section intersect. A second patterned layer is produced by moving the molten pool in the second powder layer along a second layer scan pattern that includes a second layer first section, a second layer second section, and a second layer first lap at which the second layer first section and the second layer second section intersect. The second-layer first lap joint part is overlaid on the first-layer first section or the first-layer second section. And the second layer of first lap joint part is not superposed on the first layer of first lap joint part.

Description

[0001] Cross-reference to related applications

[0002] This patent application claims priority and benefits to U.S. Provisional Patent Application No. 63 / 511,155, filed June 29, 2023, entitled "Systems and methods for using a segmented scan pattern to build large single crystal objects". Technical Field

[0003] The aspects described generally involve additive manufacturing, 3D printing, selective laser melting (SLM) printing of 3D objects, and 3D printing of cubic materials. These aspects also involve controlling the shape and overlap of the melt pool to form oriented and single-crystal microstructures in 3D printed objects. Background Technology

[0004] Objects can be printed by 3D printers using various techniques, such as stereolithography (SLA), selective laser melting (SLM), selective laser sintering (SLS), fused deposition modeling (FDM), direct metal printing (DMP), electron beam melting (EBM), directed energy deposition (DED), and laser bed powder fusion (LBPF). The field is rapidly evolving, leveraging new technologies under development and existing techniques being refined. Many techniques operate by forming patterned material layers on a substrate and then forming additional layers on top of previously generated layers. Some techniques (e.g., DED) produce patterned layers by creating a molten pool and then adding material to the pool while it is being moved. Some techniques (e.g., SLM, EBPF) produce patterned layers by laying down powdered material layers and then creating patterned layers of solid material by selectively melting the powdered material. The materials used for additive manufacturing are typically cubic materials. Cubic materials are materials that form... <100> Materials with oriented cubic crystal structures.

[0005] Additive manufacturing is a technology of only a few decades, while classical processes are technologies of thousands of years. For example, the Bronze Age began around 5,000 years ago, and the Iron Age began 3,000 years ago. Classical processes are highly refined because they have been studied and improved over thousands of years. There is a need for systems and methods to produce additively manufactured objects that meet or exceed the material properties exhibited by objects produced using classical processes. Summary of the Invention

[0006] The following summary is provided to facilitate understanding of some innovative features specific to the disclosed examples and is not intended to be a complete description. A full understanding of the various aspects of the examples can be obtained by viewing the entire specification, claims, drawings, and abstract as a whole.

[0007] One aspect of the subject matter described in this disclosure can be implemented by a method. The method may include depositing a first powder layer. The method may further include generating a first patterned layer by moving a molten pool in the first powder layer along a first layer scanning pattern, the first layer scanning pattern including a first segment of the first layer, a second segment of the first layer, and a first layer first overlap where the first segment of the first layer intersects with the second segment of the first layer. The method may further include: depositing a second powder layer on the first patterned layer; generating the second patterned layer by moving a molten pool in the second powder layer along a second layer scanning pattern; depositing a third powder layer on the second patterned layer; and generating a third patterned layer by moving a molten pool in the third powder layer along a third layer scanning pattern, the third layer scanning pattern including a third layer first segment, a third layer second segment, and a third layer first overlap where the first segment of the third layer intersects with the second segment of the third layer. The third layer first overlap is superimposed on either the first segment of the first layer or the first layer second segment, and the third layer first overlap is not superimposed on the first layer first overlap.

[0008] Another aspect of the subject matter described in this disclosure can be implemented by a system. This system may include: a powder feeder configured to generate a first powder layer and a second powder layer by depositing powder on a powder bed; a beam source configured to generate a molten pool in the powder; and a beam scanner configured to generate a first patterned layer and a second patterned layer by moving the molten pool relative to the powder bed. The first patterned layer is generated by moving the molten pool in the first powder layer along a first layer scanning pattern, the first layer scanning pattern including a first layer first segment, a first layer second segment, and a first layer first overlap where the first layer first segment intersects with the first layer second segment; the second patterned layer is generated by moving the molten pool in the second powder layer along a second layer scanning pattern, the second layer scanning pattern including a second layer first segment, a second layer second segment, and a second layer first overlap where the second layer first segment intersects with the second layer second segment, wherein the second layer first overlap overlaps with either the first layer first segment or the first layer second segment, and the second layer first overlap does not overlap with the first layer first overlap.

[0009] Another aspect of the subject matter described in this disclosure can be implemented by a system. This system may include a deposition apparatus for generating multiple powder layers by depositing powder, and a patterning apparatus for generating multiple patterned layers by moving a molten pool through the powder. A first patterned layer is generated by moving a molten pool in a first powder layer within a first powder layer along a first layer scanning pattern, the first layer scanning pattern including a first layer first segment, a first layer second segment, and a first layer first overlap where the first layer first segment intersects with the first layer second segment. A second patterned layer is generated by moving a molten pool in a second powder layer within a second powder layer along a second layer scanning pattern. A third patterned layer is generated by moving a molten pool in a third powder layer along a third layer scanning pattern, the third layer scanning pattern including a third layer first segment, a third layer second segment, and a third layer first overlap where the third layer first segment intersects with the third layer second segment. The second patterned layer in the patterned layer is located above the first patterned layer in the patterned layer and below the third patterned layer in the patterned layer, and the first overlap of the third layer does not overlap the first overlap of the first layer.

[0010] In some implementations of the method and apparatus, the first layer scan pattern includes a plurality of first layer segments and a plurality of first layer overlaps where one of the first layer segments intersects with another of the first layer segments; the third layer scan pattern includes a plurality of third layer segments and a plurality of third layer overlaps where one of the third layer segments intersects with another of the third layer segments; the third layer segments are superimposed on the first layer segments, and the third layer overlaps are not superimposed on any of the first layer overlaps. In some implementations of the method and apparatus, the growth of stray grains in the first layer overlap is prevented by moving the molten pool twice through the first layer overlap. In some implementations of the method and apparatus, the first layer first segment includes a first scan line segment, and after the molten pool moves along the first scan line segment, the molten pool extends through the entire length of the first scan line segment. In some implementations of the method and apparatus, the first layer, first segment, includes a first scan line segment and a second scan line segment. After the molten pool moves along the first scan line segment, the molten pool extends through the entire length of the first scan line segment. After the molten pool moves along the first scan line segment, the molten pool immediately moves along the second scan line segment. After the molten pool moves along the second scan line segment, the molten pool does not extend through the entire length of the first scan line segment.

[0011] In some implementations of the method and apparatus, the first layer, first segment, includes a first scan line segment and a second scan line segment. After the molten pool moves along the first scan line segment, the molten pool extends through the entire length of the first scan line segment. After the molten pool moves along the first scan line segment, the molten pool immediately moves along the second scan line segment. After the molten pool moves along the second scan line segment, the molten pool does not extend through the entire length of the first scan line segment, and due to lateral heating, the molten pool extends from the second scan line segment into the first scan line segment. In some implementations of the method and apparatus, multiple lengths of multiple scan line segments are used to set the beam power of the energy beam that generates the molten pool. In some implementations of the method and apparatus, a lookup table associates multiple scan line lengths with multiple beam power values, and multiple lengths of multiple scan line segments are used to set the beam power of the energy beam that generates the molten pool according to the lookup table. In some implementations of the method and apparatus, the beam power when scanning the first scan line segment is not equal to the beam power when scanning the second scan line segment because the first and second scan line segments have different lengths.

[0012] In some implementations of the method and apparatus, a first layer, first segment, includes multiple scan segments of multiple lengths, and the lengths of the scan segments are used to set the scanning speed of the energy beam that generates the molten pool. In some implementations of the method and apparatus, the scanning speed has a first speed value when scanning a first scan segment, a second speed value when scanning a second scan segment, and the first speed value is not equal to the second speed value because the first and second scan segments have different lengths. In some implementations of the method and apparatus, a lookup table associates multiple scan line lengths with multiple scanning speed values, the first layer, first segment includes multiple scan segments of multiple lengths, and the lengths of the scan segments are used to set the scanning speed according to the lookup table. In some implementations of the method and apparatus, an energy beam is scanned to thereby move the molten pool, the energy beam having a scanning speed and beam power, a series of molten pool images showing the molten pool shape, and the scanning speed or beam power is adaptively controlled to obtain a molten pool shape as a desired molten pool shape.

[0013] In some implementations of the method and apparatus, the first layer includes a first scan segment and a second scan segment parallel to the first scan segment. After the molten pool moves along the first scan segment, it extends through the entire length of the first scan segment. After moving along the first scan segment, the molten pool immediately moves along the second scan segment. After moving along the second scan segment, the molten pool does not extend through the entire length of the first scan segment, and due to lateral heating, the molten pool extends from the second scan segment into the first scan segment. In some implementations of the method and apparatus, multiple lengths of multiple scan segments are used to set the power of the beam source or the scanning speed of the molten pool. In some implementations of the method and apparatus, a third layer first overlap is superimposed on a first segment or a second segment of the first layer. In some implementations of the method and apparatus, the growth of stray grains is prevented by moving the molten pool twice through the first layer overlap. Attached Figure Description

[0014] The accompanying drawings further illustrate examples and, together with the detailed embodiments, serve to explain the examples disclosed herein. In the drawings, the same reference numerals refer to the same or functionally similar elements throughout the individual views, and the drawings are incorporated into and form a part of the specification.

[0015] Figure 1 These are advanced concept images of an SLM-style 3D printer based on some aspects.

[0016] Figure 2 This is a high-level concept diagram showing the scan pattern and molten pool based on some aspects.

[0017] Figure 3 This is a high-level concept diagram showing a segmented scanning pattern based on some aspects.

[0018] Figure 4 This is a high-level concept diagram showing the movement of the molten pool along a segmented scanning pattern based on several aspects.

[0019] Figure 5 This is a high-level concept diagram showing that, according to some aspects, the overlap in one layer does not superimpose on the overlap in another layer.

[0020] Figure 6 This is a high-level concept diagram illustrating a control system for controlling the beam scanner and beam source based on several aspects.

[0021] Figure 7 This is a high-level conceptual diagram showing a comparison table that correlates different scan line lengths with different beam powers or scan speeds based on several aspects.

[0022] Figure 8 This is a high-level concept diagram illustrating how scanning speed or beam power is adaptively controlled based on several factors to obtain a molten pool shape as the desired molten pool shape. Detailed Implementation

[0023] The specific values ​​and configurations discussed in the following non-restrictive examples may vary and are only referenced to illustrate one or more examples, not intended to limit their scope.

[0024] Examples will now be described more fully below with reference to the accompanying drawings. The examples disclosed herein may be embodied in different forms and should not be construed as limiting the claims; rather, these examples are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the claims to those skilled in the art. The same reference numerals always denote the same elements. A device configured to produce a result may produce that result when the device is in operation.

[0025] The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that, when used in this specification, the terms “comprising” or “including” specify the presence of the stated feature, integer, step, operation, element, or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof.

[0026] Throughout the specification and claims, terms may have subtle meanings beyond those explicitly stated, implied or suggested in the context. Similarly, the phrase "in one example" as used herein does not necessarily refer to the same example, and the phrase "in another example" as used herein does not necessarily refer to different examples. The claimed subject matter is intended to include combinations of aspects of the examples.

[0027] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms such as those defined in common dictionaries shall be interpreted as having the same meaning as they have in the context of the relevant field, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0028] It should be understood that the examples described herein are illustrative and not restrictive. These aspects may be employed in various examples without departing from the scope of the claims. Those skilled in the art will recognize or be able to determine many equivalents of the specific processes described herein using only conventional experimentation. Such equivalents are considered to be within the scope of the claims.

[0029] When used in conjunction with the term "comprising" in the claims or description, the use of the words "a" or "an" can mean "one," but it is also consistent with the meaning of "one or more," "at least one," and "one or more." Unless otherwise expressly stated, the use of the term "or" in the claims implicitly includes "and." Throughout this application, the term "about" indicates values ​​that include inherent variations in the error of the apparatus, variations in the method used to determine the value, or variations that exist between research subjects.

[0030] As used in this specification and claims, the words “comprising” (and any form of inclusion, such as “comprising” and “including”), “having” (and any form of having, such as “having” and “having”), “containing” (and any form of inclusion, such as “containing” and “containing”), or “containing” (and any form of containing, such as “containing” and “having”) are inclusive or open-ended and do not exclude additional, unlisted elements or method steps.

[0031] As used herein, the term "or combinations thereof" refers to all permutations and combinations of the items listed preceding the term. For example, "A, B, C, or combinations thereof" is intended to include at least one of the following: A, B, C, AB, AC, BC, or ABC, and also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB if the order is significant in the particular context. Continuing with this example, combinations containing repetitions of one or more items or terms are explicitly included, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, etc. Those skilled in the art will understand that there is generally no limit to the number of items or terms in any combination unless it is obvious from the context.

[0032] According to this disclosure, the systems and methods disclosed and claimed herein can be manufactured and performed without excessive experimentation. While systems and methods have been described with reference to examples, it will be apparent to those skilled in the art that variations can be applied to the systems and methods, as well as the steps or sequences of steps of the methods described herein, without departing from the concept, spirit, and scope of the claims. All such similar substitutions and modifications that are apparent to those skilled in the art are considered to be within the spirit, scope, and concept of the claims.

[0033] Figure 1 This is a high-level concept diagram of an example of an SLM-style 3D printer 100 based on some aspects. A powder feeder can be configured to produce a powder layer in a powder bed. In this example, powder feeder 110 deposits powder 112 to produce a powder layer 105 in a powder bed 108. The initially deposited powder layer (initial layer) can be located directly on the powder bed or on a substrate that can be placed in the powder bed before the powder layer is deposited. A beam source can be configured to generate a molten pool by generating an energy beam that melts some of the powder, thereby creating a molten pool. A beam scanner can be configured to generate a patterned layer by moving the molten pool. In this example, beam scanner 101 can move beam source 102 or manipulate an energy beam 111 generated by beam source 102. The energy beam can be a laser beam, an electron beam, etc. The energy beam 111 generates a molten pool 104, in which the energy beam 111 melts some of the powder in the powder bed 108. The molten pool 104 has a molten pool depth 103. The melt pool depth 103 is shown to be large enough to also melt some patterned layers 106 directly beneath the powder layer 105. In some implementations, the melt pool may extend downwards through multiple lower layers. A beam scanner moves the melt pool 104 along a path through the topmost powder layer to selectively melt some powder, thereby creating a patterned layer. The first deposited powder layer becomes the bottom patterned layer 107. 3D objects are printed by iteratively depositing powder layers and using an energy beam to melt patterns into the powder layers, thus creating patterned layers.

[0034] Figure 2 This is a high-level concept diagram showing a scan pattern and a molten pool according to some aspects. A powder layer 201 has been deposited and is ready to be patterned by moving the molten pool along a scan pattern 206. The scan pattern has a first scan line 207, a second scan line 208, etc. Figure 2 The initial scan line of scan pattern 206 is shown as the first scan line, but any scan line can be referred to as the first scan line or the second scan line. Figure 2The scan pattern 206 shown is a bidirectional scan pattern, where the scan direction changes 180 degrees from one scan line to the next. A molten pool can be generated by moving an energy beam (e.g., a laser beam, electron beam, etc.) along the scan pattern. The energy beam completely melts the material in the region of the layer to create a fully molten pool region 202. The material cools rapidly, and as the molten pool cools, grains or dendrites grow in the molten pool. The partially molten pool region 203 is the portion of the molten pool in which grains or dendrites grow. The molten pool 104 can thus include both fully molten pool regions and partially molten pool regions. The patterned region 204 is the region where the molten pool has solidified. The patterned layer 205 is generated by moving the molten pool along the scan pattern 206 and allowing the molten pool to solidify. Figure 2 As shown in the figure, the fully molten pool region 202 is shown as a black area, and the partially molten pool region 203 is shown as a gray area.

[0035] Figure 3 This is a high-level concept diagram illustrating a segmented scan pattern 301 according to some aspects. The segmented scan pattern may have two or more segments and one or more overlaps. An overlap is the area where one segment intersects with another segment. Figure 3 The scanning pattern 301 shown is a unidirectional scanning pattern, wherein the scanning direction is the same from one scanning line segment to the next. The scanning pattern 301 includes a first segment 302 and a second segment 303. Figure 3 The non-limiting example shown illustrates scanning the second segment 303 after the first segment 302. In practice, either segment can be scanned first. Furthermore, it is not necessary to scan a segment immediately after a segment, as... Figure 3 As shown. The first overlap 304 is the region where the first segment 302 and the second segment 303 intersect. When moving along the first segment 302 of the scanning pattern, the molten pool moves through the first overlap 304, and when moving along the second segment 303 of the scanning pattern, the molten pool also moves through the first overlap 304. In this way, the material in the first overlap 304 can be completely melted twice by the energy beam. The molten pool moves through the first overlap twice to prevent the growth of stray grains at the intersection of the first and second segments. An example of stray grains can be dendrites growing from the end of the scan line segment in a direction parallel to the scan line direction. The second melting of the overlapping region can prevent the growth of such stray grains.

[0036] Figure 4 This is a high-level concept diagram illustrating the movement of the molten pool along a segmented scanning pattern according to several aspects. The scanning pattern has a first segment 401, a second segment 402, and a third segment 403. Figure 4In a non-limiting example, the molten pool is scanned through a first segment 401, then through a second segment 402, and then through a third segment 403. The powder layer 400 is not patterned in the segments through which the molten pool has not yet moved. After the molten pool moves along each segment, it is seen that the molten pool extends across the entire length of that segment. Importantly, the molten pool melts each entire segment, as melting the entire segment promotes the growth of large crystal structures. Here, the problem is that the molten pool cools rapidly, which limits its length. Segmentation produces scanned patterns of segments in which the molten pool extends along the entire length of the segment, thus promoting the growth of large crystal structures. It can also be seen that each segment has many scanned segments. The molten pool can move along the first segment and then immediately along a second segment adjacent to the first segment. After the molten pool moves along the first scanned segment, it extends across the entire length of the first segment, but this portion of the molten pool solidifies rapidly and can solidify completely before the molten pool has moved completely along the second segment. Therefore, after the molten pool moves along the second scan line segment, it does not need to extend across the entire length of the first line segment. However, as Figure 4 As shown, due to lateral heating, the molten pool can extend from the second segment into the first segment. Lateral heating occurs when the heat of the molten pool moves laterally into the material near the molten pool. Melting the previously scanned line or keeping it in a molten state is important because it promotes crystal structure growth from one scanned segment to the next. The required lateral heating is another limitation on the scanned line length, as the previously scanned segment must still be hot in order to remain in a molten state or be fully melted by lateral heating.

[0037] The first overlap 406 is where the first segment 401 and the second segment 402 intersect. The second overlap 407 is where the second segment 402 and the third segment 403 intersect. As described above, the material in the overlap is melted twice by the energy beam. Therefore, the crystal structure grown in the patterned first segment can grow into the patterned second segment. After the molten pool has completely moved along all segments of all sections, the patterned layer 405 is retained and allowed to fully solidify.

[0038] Figure 5 This is a high-level concept diagram illustrating that, according to some aspects, the overlap in one layer does not superimpose on the overlap in another layer. Objects can be 3D printed by repeatedly depositing powder layers and generating patterned layers from the powder layers. The powder layers can be deposited on a substrate or on previously generated patterned layers. Figure 4 The powder layer 400 shown can be the first powder layer. The first powder layer can be an initial powder layer or a subsequent powder layer. Figure 4The segmented scan pattern shown can be an example of a first-layer scan pattern, such that the first-layer scan pattern includes a first-layer first segment 401, a first-layer second segment 402, a first-layer third segment 403, a first-layer first overlap 406, and a first-layer second overlap 407. Moving the molten pool along the first-layer scan pattern can generate a first patterned layer. A second patterned layer 507 can be generated directly on the first patterned layer 405. It can be seen that the second-layer scan pattern is orthogonal to the first-layer scan pattern. Furthermore, the second-layer scan pattern is not segmented because each scan line of the second-layer scan pattern is smaller than a threshold. The threshold is a value that allows the molten pool to extend the entire length of the scan line and is used for lateral heating into the previous scan line to promote the growth of the crystal structure from the previous scan line into the molten pool.

[0039] A third patterned layer 508 can be directly generated on the second patterned layer 507. It can be seen that the third scan pattern is parallel to the first scan pattern and orthogonal to the second scan pattern. Experiments show that large crystals can be generated by rotating the scan pattern from one layer to another, such as... Figure 5 As shown. The third layer scan pattern can be considered as a segmented scan pattern with a first segment, a second segment, and a third segment. Moving the molten pool along the first segment of the third layer generates the first segment 511 of the third patterned layer. Figure 5 In the example, moving the molten pool along the second segment of the third layer generates the second segment 510 of the third patterned layer. Moving the molten pool along the third segment of the third layer generates the third segment 509 of the third patterned layer. The first overlap of the third layer is where the first segment of the third layer and the second segment of the third layer intersect. The first overlap of the third patterned layer 513 is located where the molten pool moves through the first overlap of the third layer. The second overlap of the third layer is where the second segment of the third layer and the third segment of the third layer intersect. The second overlap of the third patterned layer 512 is located where the molten pool moves through the second overlap of the third layer.

[0040] like Figure 5As shown, the overlaps in the third patterned layer do not superimpose on the overlaps in the first patterned layer. More specifically, the first overlap 513 of the third patterned layer superimposes on the first patterned layer 405, but not on the first overlap 406 or the second overlap 407 of the first patterned layer. Furthermore, the second overlap 512 of the third patterned layer superimposes on the first patterned layer 405, but not on the first overlap 406 or the second overlap 407 of the first patterned layer. Importantly, overlaps in a layer do not superimpose on the nearest lower layer (previous layer) or any overlaps in many previous layers to facilitate the growth of large crystal structures through these layers. The previous layer can be any patterned layer below the top layer. Patterned segments not in overlaps are more likely to have higher quality crystal structures than patterned segments in overlaps. Therefore, higher quality crystal structures are more likely to grow from the lower layer to the top overlap.

[0041] Figure 6 This is a high-level concept diagram illustrating a control system 601 that controls a beam scanner and a beam source according to some aspects. The control system may be a computer running software for controlling a 3D printer. When running the control system software, the computer can send control signals to the beam scanner 101, the beam source 102, and other components of the 3D printer. Those skilled in the art have long and extensive experience running control system software on a computer that controls a 3D printer. The control system may store scan patterns 602. Scan patterns 602 may include a first layer scan pattern 603, a second layer scan pattern 611, a last layer scan pattern 612, and other layer scan patterns. Layer scan patterns may include segments. For example, a first layer scan pattern 603 is shown as including a first layer first segment 604, a first layer second segment 609, a first layer last segment 610, and may include a number of other first layer segments. Segments may include path data associated with scan speed and beam power. For example, the first segment 604 of the first layer is shown as a table with rows, each row including an x-coordinate 605, a y-coordinate 606, a scan speed value 607, and a beam power value 608. The control system 601 can read the table rows and then command the beam scanner 101 and the beam source 102 to set the energy beam to the beam power indicated by the beam power value 608, and to move the molten pool from its current position to the position indicated by the x-coordinate 605 and y-coordinate 606 at a scan speed indicated by the scan speed value 607.

[0042] Figure 7This is a high-level conceptual diagram of a reference table 701 that correlates different scan line lengths with different beam powers or scan speeds according to some aspects. The amount of energy deposited by the beam into the volume of the patterned material depends on the beam power and how long the beam contacts the material volume. Here, the energy beam scans along the scan pattern, thus moving the molten pool. Therefore, the amount of energy deposited into the volume depends on the scan speed and the beam power. As mentioned above, it is desirable for the molten pool to extend completely through the entire scan line or segment, and it is desirable for lateral heating to melt into the previous scan line. It is also desirable for the molten pool to extend slightly into the previous layer directly below the top layer. The amount of energy deposited is limited because too much energy simply melts the object being produced, melting too large a volume, thus reducing print resolution, etc. Therefore, the beam power 704, scan speed 703, or both can be a function of the scan length 702. The scan length is the length of a segment in a section or a scan line in a scan pattern. For example, the molten pool moves along the entire scan line while patterning... Figure 5 The second patterned layer 507 is shown. The molten pool moves along the scan line segment while being patterned. Figure 5 The first patterned layer 405 and the third patterned layer are shown. A table 701 comparing scan length, scan speed, and scan power can be used to determine... Figure 6The values ​​in the scan pattern 602 shown. Alternatively, lookup table 701 can be used to set the beam power and scan speed during the printing operation. In the example, when the first segment in the line segment has a first length 705, the energy beam generates a molten pool according to the lookup table, and this first length can be looked up in lookup table 701 to determine the first beam power value 707 and the first scan speed value 708. In another example, the lookup table does not contain entries for length, and the first beam power value 707 and the first scan speed value 708 are calculated via interpolation. The beam source can be set to the first beam power value 707 as the molten pool moves along the first segment in the line segment. The scan speed of the beam scanner can be set to the first scan speed value 708 as the molten pool moves along the first segment in the line segment. The second segment in the line segment can have a second length 706. The beam power or scan speed used for the second segment in the line segment may not be equal to the beam power or scan speed used for the first segment in the line segment because the first segment in the line segment and the second segment in the line segment have different lengths. When the first length 705 is not equal to the second length 706, the line segments have different lengths. Therefore, the second length 706 can be looked up in or calculated from the lookup table 701 (e.g., via interpolation) to determine the second beam power value 709 and the second scan speed value 710. The beam source can be set to the second beam power value 709 as the molten pool moves along the second line segment. The scan speed of the beam scanner can be set to the second scan speed value 710 as the molten pool moves along the second line segment. Some implementations can use a single scan speed and vary the beam power. Some implementations can use a single beam power and vary the scan speed. Some implementations can vary both the scan speed and the beam power.

[0043] Figure 8This is a high-level concept diagram illustrating adaptive control of scan speed or beam power based on several factors to obtain a desired molten pool shape. Imager 809 can image the molten pool 104 and generate a molten pool image 806, which is an image of the molten pool. Imager 809 can be a camera operating in the visible light range (visible to humans), the infrared light range, etc. Molten pool image 806 can be a time series of molten pool images, such as one image every tenth of a second, one image every thirtyth of a second, etc. Molten pool image 806 can be received by image analyzer 804, which determines molten pool shape 802. Molten pool comparator 803 can compare molten pool shape 802 with desired molten pool shape 801. For example, the desired molten pool shape may extend the entire length of the nearest scan line or scan segment, and the molten pool may extend to the middle (lateral) of the previous scan line or scan segment. The difference between the observed molten pool shape and the desired molten pool shape can indicate an increase in beam power, a decrease in beam power, an increase in scan speed, a decrease in scan speed, etc. The parameter adjuster 805 can generate a beam power adjustment 807 sent to the beam source 102 or a scan speed adjustment 808 sent to the beam scanner 101. The beam power adjustment 807 and the scan speed adjustment 808 can give the molten pool 104 the desired molten pool shape.

Claims

1. A method, the method comprising: Deposit the first powder layer; A first patterned layer is generated by moving a molten pool in the first powder layer along a first layer scanning pattern, the first layer scanning pattern including a first layer first segment, a first layer second segment and a first layer first overlap, wherein the first layer first segment and the first layer second segment intersect at the first layer first overlap; A second powder layer is deposited on the first patterned layer; The second patterned layer is generated by moving the molten pool in the second powder layer along the second layer scanning pattern; Deposit a third powder layer on the second patterned layer; and A third patterned layer is generated by moving the molten pool in the third powder layer along a third scanning pattern. The third scanning pattern includes a third layer first segment, a third layer second segment, and a third layer first overlap, wherein the third layer first segment and the third layer second segment intersect at the third layer first overlap. in: The third layer's first overlapping portion is superimposed on the first layer's first section or the first layer's second section; and The third layer first overlap portion does not overlap the first layer first overlap portion.

2. The method according to claim 1, wherein: The first layer scan pattern includes multiple first layer segments and multiple first layer overlaps, wherein one of the first layer segments intersects with another of the first layer segments; The third-layer scanning pattern includes multiple third-layer segments and multiple third-layer overlaps, wherein one of the third-layer segments intersects with another of the third-layer segments at the multiple third-layer overlaps; The third layer segment is superimposed on the first layer segment; and The third layer overlap does not superimpose on any of the first layer overlaps.

3. The method according to claim 1, wherein, The growth of stray grains in the first overlap of the first layer is prevented by moving the molten pool through the first overlap twice.

4. The method according to claim 1, wherein: The first segment of the first layer includes a first scan line segment; and After the molten pool moves along the first scan line segment, the molten pool extends through the entire length of the first scan line segment.

5. The method according to claim 1, wherein: The first segment of the first layer includes a first scan line segment and a second scan line segment; After the molten pool moves along the first scan line segment, the molten pool extends through the entire length of the first scan line segment; Immediately after the molten pool moves along the first scan line segment, the molten pool moves along the second scan line segment; and After the molten pool moves along the second scan line segment, the molten pool does not extend through the entire length of the first scan line segment.

6. The method according to claim 1, wherein: The first segment of the first layer includes a first scan line segment and a second scan line segment; After the molten pool moves along the first scan line segment, the molten pool extends through the entire length of the first scan line segment; Immediately after the molten pool moves along the first scan line segment, the molten pool moves along the second scan line segment; After the molten pool moves along the second scan line segment, the molten pool does not extend through the entire length of the first scan line segment; and The molten pool extends from the second scan segment into the first scan segment due to lateral heating.

7. The method according to claim 1, wherein, Multiple scan line segments of multiple lengths are used to set the beam power of the energy beam that generates the molten pool.

8. The method according to claim 1, wherein: The lookup table correlates multiple scan line lengths with multiple beam power values; and Multiple lengths of multiple scan lines are used to set the beam power of the energy beam that generates the molten pool according to the lookup table.

9. The method according to claim 1, wherein, The beam power when scanning the first scan segment is not equal to the beam power when scanning the second scan segment, because the first scan segment and the second scan segment have different lengths.

10. The method according to claim 1, wherein: The first segment of the first layer includes multiple scan line segments of multiple lengths; and The length of the scan line segment is used to set the scanning speed of the energy beam that generates the molten pool.

11. The method of claim 10, wherein: The scanning speed has a first speed value when scanning the first scan segment in the scan segment; The scanning speed has a second speed value when scanning the second scan segment of the scan line segment; and The first speed value is not equal to the second speed value because the first scan segment and the second scan segment in the scan segment have different lengths.

12. The method according to claim 1, wherein: The lookup table correlates multiple scan line lengths with multiple scan speed values; The first segment of the first layer includes multiple scan line segments of multiple lengths; and The length of the scan line segment is used to set the scan speed according to the lookup table.

13. The method according to claim 1, wherein: The energy beam is scanned, thereby moving the molten pool; The energy beam has a scanning speed and beam power; A series of images of the molten pool show the shape of the molten pool; and The scanning speed or the beam power is adaptively controlled to obtain the molten pool shape as the desired molten pool shape.

14. A system comprising: A powder feeder configured to produce a first powder layer and a second powder layer by depositing powder on a powder bed; A beam source configured to generate a molten pool in the powder; as well as A beam scanner configured to generate a first patterned layer and a second patterned layer by moving the molten pool relative to the powder bed. in: The first patterned layer is generated by moving the molten pool in the first powder layer along the first layer scanning pattern, the first layer scanning pattern including a first layer first segment, a first layer second segment and a first layer first overlap, wherein the first layer first segment and the first layer second segment intersect at the first layer first overlap; The second patterned layer is generated by moving the molten pool in the second powder layer along the second layer scanning pattern, the second layer scanning pattern including a second layer first segment, a second layer second segment, and a second layer first overlap, wherein the second layer first segment and the second layer second segment intersect at the second layer first overlap; The second layer's first overlap is superimposed on the first layer's first section or the first layer's second section; and The second layer first overlap does not superimpose on the first layer first overlap.

15. The system according to claim 14, wherein, The growth of stray grains is prevented by moving the molten pool through the first layer overlap twice.

16. The system according to claim 14, wherein: The first layer includes a first scan line segment and a second scan line segment parallel to the first scan line segment; After the molten pool moves along the first scan line segment, the molten pool extends through the entire length of the first line segment; Immediately after the molten pool moves along the first scan line segment, the molten pool moves along the second scan line segment; After the molten pool moves along the second scan line segment, the molten pool does not extend through the entire length of the first line segment; and The molten pool extends from the second scan line segment into the first line segment due to lateral heating.

17. The system according to claim 14, wherein, Multiple lengths of multiple scan segments are used to set the power of the beam source or the scanning speed of the molten pool.

18. A system comprising: A deposition apparatus for producing multiple powder layers by depositing powder; as well as A patterning apparatus for producing multiple patterned layers by moving a molten pool through the powder; in: The first patterned layer in the patterned layer is generated by moving the molten pool in the first powder layer in the powder layer along the first layer scanning pattern. The first layer scanning pattern includes a first layer first segment, a first layer second segment, and a first layer first overlap, wherein the first layer first segment and the first layer second segment intersect at the first layer first overlap. The second patterned layer in the patterned layer is generated by moving the molten pool in the second powder layer in the powder layer along the second layer scanning pattern; The third patterned layer in the patterned layer is generated by moving the molten pool in the third powder layer along the third layer scanning pattern. The third layer scanning pattern includes a third layer first segment, a third layer second segment, and a third layer first overlap, wherein the third layer first segment and the third layer second segment intersect at the third layer first overlap. The second patterned layer in the patterned layer is above the first patterned layer in the patterned layer and below the third patterned layer in the patterned layer; and The third layer first overlap portion does not overlap the first layer first overlap portion.

19. The system according to claim 18, wherein, The third layer first overlap portion is superimposed on the first layer first section or the first layer second section.

20. The system according to claim 18, wherein, The growth of stray grains is prevented by moving the molten pool through the first layer overlap twice.

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