Block-based printing with dynamic beam shaping

Abstract

Aspects of additive manufacturing of constructs using tile-based printing with dynamic beam shaping are provided. An apparatus may include a powder bed depositor to deposit a layer of powder material in a powder bed, a laser beam source configured to generate a laser beam, a beam shaping component configured to adjust an energy distribution of the laser beam to obtain a beam energy distribution, and a controller. The controller may be configured to obtain information of a layer of powder material and control the beam shaping component to adjust a beam energy distribution of the laser beam to correspond to a tile energy distribution associated with a plurality of tiles in the layer. Further, the controller may be configured to apply a laser beam pulse to the plurality of blocks to fuse portions of the construct corresponding to the respective blocks.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the priority of U.S. Patent Application No. 63 / 417,983, entitled "TILE - BASED PRINTING WITH DYNAMIC BEAM SHAPING", filed on October 20, 2022, the entire content of which is incorporated herein by reference as described herein. Technical Field

[0003] This disclosure generally relates to additive manufacturing, and more particularly, to systems and methods for dynamically shaping a laser beam during additive manufacturing. Background Art

[0004] Powder - bed fusion (PBF) systems can produce structures with complex geometries (referred to as build parts), including some shapes that are difficult or impossible to create with conventional manufacturing processes. PBF systems include additive manufacturing (AM) techniques for creating build parts layer by layer. Each layer or slice can be formed by depositing a layer of powder and then fusing (e.g., melting and cooling) the area in the powder layer that coincides with the cross - section of the build part in that layer via a laser beam. This process can be repeated to form the next slice of the build part, and so on, until the build part is complete. Since each layer is deposited on top of the previous layer, PBF can be likened to forming a structure piece by piece from scratch.

[0005] However, these AM systems lack optimized control of the laser beam passing through the layer to melt and consolidate the material in front of the beam in an effective manner. In addition, these AM systems lack optimized dynamic beam shaping of the laser beam to optimize various final properties of the build part. Summary of the Invention

[0006] Several aspects of laser - based PBF based on variable beam geometry and systems, methods, and non - transient computer - readable media for additive manufacturing build parts will be described more fully below.

[0007] In one aspect of the present disclosure, an apparatus for additive manufacturing a build part is provided. The apparatus includes a powder - bed depositor configured to deposit a layer of powder material in a powder bed. The apparatus further includes a laser - beam source configured to generate a laser beam. The apparatus also includes a beam - shaping component configured to adjust the energy distribution of the laser beam to obtain a beam energy distribution. In addition, the apparatus includes a controller.

[0008] In one or more embodiments, the controller may be configured to obtain information about a powder material layer, the information including a plurality of blocks of the layer and a block energy distribution associated with each of the blocks. For example, the block energy distribution may include one or more parameters. The parameter may at least include length, width, depth, power density, or time. Additionally, the block energy distribution may include an energy distribution based on the geometry of the build piece. The geometry of the build piece may include the geometry of the edges of the build piece. Additionally, the block energy distribution may include an energy distribution that varies over time. The energy distribution that varies over time may include a melting period and at least a preheating period or a post-heating period. Additionally, the block energy distribution associated with each of the blocks may include an energy distribution based at least on the residual stress of the block, the microstructure of the block, or the pulse velocity.

[0009] In one or more embodiments, the controller may be configured to control a beam shaping component to adjust the beam energy distribution to correspond to the block energy distribution of a first block among the plurality of blocks, thereby obtaining a first beam energy distribution. In one or more embodiments, the controller may be configured to apply a laser beam pulse having the first beam energy distribution to the first block to fuse a portion of the build piece corresponding to the first block. In one or more embodiments, the controller may be configured to control the beam shaping component to adjust the beam energy distribution to correspond to the block energy distribution of a second block among the plurality of blocks, thereby obtaining a second beam energy distribution, wherein the second beam energy distribution is different from the first beam energy distribution. In one or more embodiments, the first beam energy distribution and the second beam energy distribution have different power densities over time. In one or more embodiments, a portion of the first block and a portion of the second block overlap. In one or more embodiments, the controller may be configured to apply a laser beam pulse having the second beam energy distribution to the second block to fuse a portion of the build piece corresponding to the second block.

[0010] In one or more embodiments, the apparatus may include a sensor configured to measure the temperature of the first block after the controller applies a laser beam pulse to the first block. The apparatus may further include a camera configured to capture an image of the first block after the controller applies a laser beam pulse to the first block. The image captured by the camera can be used to observe how a particular block or the powder material layer generally transitions from pre-fusion to the current state of build piece fusion. In other words, the camera image can provide information about which components of the powder material layer have cooled, transformed, or otherwise moved in position. The apparatus may further include a steering system having a laser beam source.

[0011] In another aspect of the present disclosure, a method for additive manufacturing a build is provided. The method includes depositing a layer of powder material in a powder bed. The method further includes obtaining information about the layer of powder material, the information including a plurality of zones of the layer and a zone energy distribution associated with each of the zones. In one or more embodiments, the zone energy distribution includes one or more parameters. For example, the parameters may include at least one or more of length, width, depth, power density, or time. In one or more embodiments, the zone energy distribution associated with each of the plurality of zones includes an energy distribution based on the geometry of the build.

[0012] The method further includes controlling a beam shaping component to adjust the beam energy distribution associated with a laser beam to correspond to the zone energy distribution of a first zone of the plurality of zones, thereby obtaining a first beam energy distribution. Additionally, the method includes applying a pulsed laser beam having the first beam energy distribution to the first zone to fuse a corresponding portion of the build. The method may include controlling the beam shaping component to adjust the beam energy distribution associated with the laser beam to correspond to the zone energy distribution of a second zone of the plurality of zones, thereby obtaining a second beam energy distribution, wherein the second beam energy distribution is different from the first beam energy distribution. In one or more embodiments, the first beam energy distribution and the second beam energy distribution have different power densities over time. In one or more embodiments, a portion of the first zone and a portion of the second zone overlap. Additionally, the method may include applying a pulsed laser beam having the second beam energy distribution to the second zone to fuse a corresponding portion of the build.

[0013] In one or more embodiments, the method further includes determining a processing order for each of the plurality of zones. In one or more embodiments, the method further includes determining the shape of the laser beam to be applied to each of the plurality of zones. In one or more embodiments, the method may include determining the size of each of the plurality of zones. In one or more embodiments, the method additionally includes determining the beam velocity of the laser beam to be applied to each of the plurality of zones.

[0014] In another aspect of the present disclosure, a non-transitory computer-readable medium storing computer-executable instructions executable by a processor for additive manufacturing a build is also provided to perform the methods disclosed herein.

[0015] Those skilled in the art will readily appreciate other aspects from the following detailed description, in which only several exemplary embodiments are shown and described by way of illustration. As those skilled in the art will recognize, the concepts described herein can be used in other and different embodiments, and several details can be modified in various other aspects, all of which do not depart from the present disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Aspects of the concepts described herein will now be presented in the detailed description by way of example and not limitation in the accompanying drawings, in which:

[0017] Figure 1A-1D Corresponding side views of an exemplary L-PBF system during different operating phases are shown.

[0018] Figure 2A-2C is a schematic diagram of an exemplary powder bed showing a powder material layer subdivided into a plurality of blocks.

[0019] Figure 2D An exemplary graph showing the variation of laser beam penetration with block position and power density is shown.

[0020] Figure 3 is a flowchart of an exemplary method for additive manufacturing a build part in an L-PBF apparatus. DETAILED DESCRIPTION

[0021] The detailed description set forth below in connection with the appended drawings is intended as a description of various exemplary embodiments of the concepts disclosed herein and is not intended to represent the only embodiments in which the present disclosure can be practiced. The term "exemplary" as used herein means "serving as an example, instance, or illustration" and should not necessarily be construed as preferred or advantageous over other embodiments presented in the present disclosure. The detailed description includes specific details for the purpose of providing a thorough and complete disclosure that fully conveys the scope of the concepts to those skilled in the art. However, the present disclosure may be practiced without these specific details. In some instances, well-known structures and components may be shown in block diagram form or omitted entirely to avoid obscuring the various concepts presented in the present disclosure.

[0022] Although the present disclosure generally relates to laser-based PBF (L-PBF) systems, it should be understood that such L-PBF systems can encompass a variety of AM techniques. Thus, among other things, the L-PBF process can include the following printing techniques: Direct metal laser sintering (DMLS), Selective laser melting (SLM), and Selective laser sintering (SLS). Other PBF processes to which the principles of the present disclosure are equally applicable include processes that are currently under development or are in commercial development. While the specific details of each such process are omitted to avoid over-obscuring the key concepts of the present disclosure, it should be understood that the claims are intended to cover such technologies and related structures.

[0023] The L-PBF system can produce metallic and polymeric structures (referred to as build parts) with complex geometries, including shapes that are difficult or impossible to create using conventional manufacturing processes. The L-PBF system creates the build part layer by layer, i.e., slice by slice. Each slice can be formed by a process of depositing a layer of powder and fusing (e.g., melting and cooling) the regions of the powder layer that coincide with the cross-section of the build part in the slice. This process can be repeated to form the next slice of the build part, and so on, until all layers are deposited and the build part is complete.

[0024] In a conventional L-PBF system, the path of the laser through the top layer of powder (i.e., the scan pattern) is typically a pattern of parallel lines drawn back and forth across the current build layer. The orientation of the lines can vary in some regions or can remain consistent throughout the layer. The L-PBF system then moves to the next layer and continues to direct the laser beam in a stripe pattern. For each layer, the conventional L-PBF system applies a constant energy distribution.

[0025] Aspects of the present disclosure relate to advantageous laser beam scanning apparatuses, methods, and non-transitory computer-readable media for L-PBF systems, where a build layer (e.g., a lamina) is subdivided into identified regions (i.e., patches), and then a customized energy distribution of a laser beam is applied to each individual patch in the build layer. In one or more embodiments, a patch is a two-dimensional region of a powder layer. In one or more embodiments, a patch is a three-dimensional voxel of a powder layer. The energy flux applied to each patch depends on one or more variables of the laser beam, which include the position of the beam application in two or three dimensions, the power of the beam, and the duration for which the beam is activated and focused on a given patch. Thereafter, the L-PBF system disclosed herein scans additional patches and applies a customized energy distribution to these corresponding patches in order to fuse these portions of the build to the build layer. Additionally, the disclosed systems and methods adjust the energy distribution of the laser beam to account for the characteristics of different patches, thereby optimizing the processing order of the patches. For example, adjusting the energy distribution from patch to patch can improve the characteristics of the final build, such as improving residual stress, increasing the fusion rate, or achieving a desired microstructure in the build.

[0026] In one or more embodiments, patches overlap at one or more edges of adjacent patches. For example, in the case where adjacent patches share a boundary, the area or volume of each patch will slightly extend into the area and volume of each adjacent patch to provide a “stitched” design where the build layer has no regions without patch coverage. The power of the L-PBF system can be tuned to allow for a fine overlap between patches. In one or more embodiments, patches do not overlap at the edges of adjacent patches, but rather the edges of adjacent patches are adjacent to each other.

[0027] In the L-PBF systems disclosed herein, the laser beam can be configured to use a variable beam or spot geometry (i.e., beam shaping) to increase build rates and provide additional control and flexibility in the manufacturing process. The laser spot is the surface area irradiated by the laser. Instead of using a laser beam configured to terminate in a tiny nearly point-like spot with a small radius that remains constant over time, the laser beam can instead be configured to use a variable beam or spot geometry based on the energy distribution of the blocks or build parts to be fused, depending on the scan direction. For example, the beam geometry (i.e., the area of the surface of the printed material irradiated by the laser) can be linear, square, rectangular, triangular, an asymmetric shape, or any other two-dimensional shape. The identified beam geometry can then be applied to the surface of the printed material using two-dimensional or three-dimensional scanning. When doing so, the laser beam can be applied during a PBF printing operation such that a larger continuous area of the powder bed can be processed at any given time. In an embodiment, the beam geometry can be dynamically changed during a 3-D printing operation. Thus, for example, an L-PBF 3-D printer can use a correspondingly large beam geometry to fuse a larger area, and subsequently or periodically, the 3-D printer can change the beam geometry to a thin line or a normal point-like shape to scan the corners of the object and / or to fuse details of the build part at a smaller scale.

[0028] In one or more embodiments, the dynamic beam shaping disclosed herein can be performed via a beam shaping component by changing the beam focal length or beam intensity in order to change the beam shape using a programmable laser beam source. The beam shaping component can include one or more fixed or movable optical elements in any necessary or suitable physical form. The beam shaping component can also include multiple diffractive, reflective, and refractive devices such as diffractive beam splitters, diffractive diffusers, phase plates, lenses, and mirrors. These laser beam sources can be programmed to output a pulsed laser beam whose beam shape varies according to the block to be processed.

[0029] According to aspects of the present disclosure, the laser beam geometry can be adjusted based on the energy distribution of the object (build part) to be produced, according to the block energy distribution associated with each of a plurality of blocks in a build layer. The laser beam geometry can be adjusted at the start of the scan, on a slice-by-slice basis, on a block-by-block basis, at a specified time within a slice, or dynamically in real time. Additionally, the laser beam geometry can also vary continuously as the laser scans through the powder bed, the variation being, for example, according to the expected structure of the object identified in a computer aided design (CAD) contour.

[0030] Using variable beam shaping can advantageously increase the throughput of the L-PBF process. Additionally, adjusting the beam shaping as described herein can allow for the application of laser power over a larger area onto the powder bed, meaning that a smaller energy flux can be maintained to reduce evaporation of the material. Further, given the nature of the adjusted laser spot geometry, the energy distribution of the spot geometry can be adjusted according to the scan vector (the direction of scanning) to provide heating and cooling rate control. Controlling the cooling rate during the solidification process can allow for reducing thermal stress and altering the microstructure in the resulting part to achieve desired material properties. Additionally, adding three-dimensional energy flux in a particular powder layer also improves the residual stress and the microstructure of the build.

[0031] In one or more embodiments, the processing order of the fused blocks can be optimized for various variables such as residual stress, build time speed, or material distribution on the build layer. For example, to manage the residual stress in a block, the laser beam can be pulse-modulated according to different parameters to heat portions of the block at different lengths, widths, or depths. The heating can occur below, at, or above the powder melting point in order to build portions of the build in the corresponding blocks of the layer and stitch these portions to portions in adjacent layers (i.e., in the Z-axis) to manage the residual stress during laser beam exposure. Additionally, the processing order of the blocks can take into account the characteristics of adjacent blocks, including temperature, the state of the build structure in these blocks, etc. In one or more embodiments, the processing order of the blocks is dynamically determined substantially in real time.

[0032] Figure 1A -D shows corresponding side views of an exemplary laser-based PBF (L-PBF) system 100 during different operational stages. As described above, Figure 1A -D is one of many suitable examples of an L-PBF system that employs the principles of the present disclosure. It should also be noted that Figure 1A the elements in -D and other figures in this disclosure are not necessarily drawn to scale, but may be drawn larger or smaller for the purpose of better illustrating the concepts described herein. The L-PBF system 100 can include a depositor 101 that can deposit each layer of powder material; a controller 102; a laser beam source 103 that can generate a laser beam; a beam shaping component 104 that can shape the laser beam according to a selected beam geometry; a deflector 105 that can apply the laser beam in the form of the selected beam geometry to fuse the powder material; and a build plate 107 that can support one or more builds (such as build 109).

[0033] The controller 102 or other processing system may coordinate the L-PBF additive manufacturing process. The controller 102 may be a central processing unit or other known type of processor. In one or more embodiments, the controller 102 may be operably coupled to a positioning system that controls the structure of the L-PBF system 100 (e.g., the depositor 101, the laser beam source 103, the beam shaping component 104, etc.). In this way, the organized operation time can be carefully coordinated by the central controller.

[0034] Although the laser beam source 103 and the beam shaping component 104 are generally identified as separate components, in some exemplary embodiments, the functions of these two components may be included as part of a single integrated structure without departing from the scope of the present disclosure.

[0035] In one or more embodiments, the laser beam source 103 is included in or coupled to a steering system or a gantry system.

[0036] The L-PBF system 100 may also include a build platform 111 located within the powder bed container. The walls 112 of the powder bed container may generally define the boundary of the powder bed container, which is defined between the sides of the walls 112 and a portion of the build platform 111 below. The build platform 111 may gradually lower the build plate 107 so that the depositor 101 can deposit the next layer of powder material. The L-PBF system 100 may additionally include a chamber 113 that can enclose other components of the L-PBF system 100 (e.g., the controller 102, the laser beam source 103, the beam shaping component 104, and the deflector 105), thereby protecting such other components, enabling atmosphere and temperature regulation, and reducing the risk of contamination. In addition, the L-PBF system 100 may include temperature sensors 122 to monitor the atmospheric temperature, the temperature of the powder 117, and / or the temperature of the components of the L-PBF system 100. The depositor 101 may include a hopper 115, for example, the hopper contains the powder 117, such as metal powder. The depositor 101 may also include a leveller 119 that can level the top of each layer of deposited powder (e.g., see Figure 1B of the powder layer thickness 123) by shifting the deposited powder 117 above a predefined layer height (e.g., corresponding to Figure 1C of the powder layer 125).

[0037] Specifically referring to Figure 1A , this figure shows the L-PBF system 100 after a build piece 109 has been fused, but before the next layer of powder 117 has been deposited. In fact, Figure 1AThe time showing the current state where the L-PBF system 100 has deposited and fused slices in multiple layers (e.g., 150 layers) to form the build 109 (e.g., formed by 150 slices). The multiple deposited layers have created a powder bed 121 that includes powder that has been deposited but not fused.

[0038] Figure 1B Shows the L-PBF system 100 at a stage where the build platform 111 can lower the powder layer thickness 123. The lowering of the build platform 111 causes the build 109 and the powder bed 121 to drop by the powder layer thickness 123, such that the top of the build and the powder bed is lower than the top of the powder bed container wall 112 by an amount equal to the powder layer thickness. In this way, for example, a space of uniform thickness equal to the powder layer thickness 123 can be created above the top of the build 109 and the powder bed 121.

[0039] Figure 1C Shows the L-PBF system 100 at a stage where the depositor 101 is positioned to deposit powder 117 into the space created above the top surfaces of the build 109 and the powder bed 121 and defined by the powder bed container wall 112. In this example, the depositor 101 gradually moves above the defined space while releasing the powder 117 from the hopper 115. The leveling device 119 can level the released powder to form a powder layer 125 having a thickness substantially equal to the powder layer thickness 123 (see Figure 1B ). Thus, the powder 117 in the L-PBF system 100 can be supported by a powder material support structure that can include, for example, the build plate 107, the build platform 111, the build 109, the wall 112, etc. It should be noted that the thickness of the shown powder layer 125 (e.g., Figure 1B the powder layer thickness 123) can be greater than the actual thickness for the example discussed above with reference to Figure 1A the 150 previously deposited layers.

[0040] In one or more embodiments, information about the powder layer 125 can be obtained by one or more sensors 126 of the L-PBF system 100. The sensors 126 can capture information about the powder layer 125 and other conditions within the chamber 113. For example, the sensors 126 can collect information about the amount of powder in portions of the powder layer, the temperature of the layer at different portions of the powder layer, and other (including depth) or other characteristics of the layer. In one or more embodiments, the sensors 126 are operably coupled to the controller 102 such that the information collected by the sensors can be processed by the controller. In one or more embodiments, the controller 102 can receive information that divides the powder material layer into a plurality of blocks or regions of layers. In one or more embodiments, a block energy distribution is associated with each of the blocks in the block. The blocks can form a grid, can overlap with adjacent blocks, or can have other shapes and sizes according to the needs of the build.

[0041] In automated embodiments where the temperature is closely monitored (e.g., using a temperature sensor adjacent to the build), the block order for printing can occur in real time. That is, the controller can determine the order based on the temperature of the deposited layer, the expected geometry of the completed build, or other factors after printing has started.

[0042] Figure 1D An L-PBF system 100 is shown that generates the next slice in the build 109 after the deposition of the powder layer 125 ( Figure 1C ). Refer to Figure 1D, the laser beam source 103 can generate a laser beam. The beam shaping component 104 can be used to change the geometry of the laser beam into a linear, square, rectangular or other two-dimensional shape. In some aspects, the beam shaping component 104 can shape the laser beam through a phase plate and free-space propagation. The beam shaping component 104 can include a plurality of diffractive, reflective and refractive devices, such as diffractive beam splitters, diffractive diffusers, phase plates, lenses, mirrors or other optical elements. For example, the change in the size and geometry of the laser beam 127 can be achieved by the motorized displacement of the optical elements of the beam shaping component 104. In one or more embodiments, the controller 102 can execute instructions that are configured to control the beam shaping component 104 to adjust the beam energy distribution associated with the laser beam source 103 to correspond to the block energy distribution of the first block among a plurality of blocks in the powder layer 125, thereby obtaining a first beam energy distribution. In some aspects, the geometry of the beam shape can be set according to the build part 109. The geometry of the beam shape can be modified on a block-by-block or slice-by-slice basis based on the geometry of the build part to reduce the scanning time and achieve the residual stress or specific microstructure of the build part for a specific block, slice or layer. In some aspects, the geometry of the beam shape can also be modified in intermediate blocks, intermediate layers or even continuously during the entire scan of the build part 109.

[0043] Thereafter, the controller 102 can be configured to apply a laser beam pulse having the first beam energy distribution to the first block to fuse a portion of the build part corresponding to the first block. The deflector 105 can apply the laser beam 127 in the selected geometry to fuse the first block identified in the build part 109. In various embodiments, the deflector 105 can include one or more gimbals and actuators that can rotate and / or translate the laser beam source 103 and / or the beam shaping component 104 to position the laser beam 127. In various embodiments, the laser beam source 103, the beam shaping component 104 and / or the deflector 105 can modulate the laser beam, for example, turning the laser beam on and off when the deflector scans so that the laser beam is only applied to the appropriate area of the powder layer. For example, in various embodiments, the laser beam can be modulated by a digital signal processor (DSP).

[0044] In some aspects, the controller 102 can be configured to control the beam shaping component 104 to adjust the beam energy distribution so that it corresponds to the block energy distribution of the second block among a plurality of blocks, thereby obtaining a second beam energy distribution. For example, the second beam energy distribution is different from the first beam energy distribution. Thereafter, the controller 102 can be configured to apply a pulse of the laser beam source 103 having the second beam energy distribution to the second block to fuse a portion of the build part corresponding to the second block.

[0045] In one or more embodiments, the beam energy distribution can be adjusted based on a customized time profile. In other words, the controller can configure the laser beam to be activated at an initial power for a duration from t0 to t1 and then at a modified power for a duration from t1 to t2. For example, the controller can configure the laser beam to be activated at 400 watts for a selected duration over a particular region and then at 600 watts for a different duration over the same region. Additionally, the controller can configure the system to scan the laser beam across the region as the applied laser beam power changes. In this way, the systems herein can vary the energy input over time to achieve a desired microstructure in the build.

[0046] As Figure 1D shown, most of the fusion of the regions of the powder layer 125 occurs in the region where the powder layer is on top of the previous slice, i.e., the previously fused powder. An example of such a region is the surface of the build 109. Figure 1D The fusion of the powder layer in

[0047] Now referring to Figure 2A-2C , an exemplary powder bed 200 including a deposited layer of powder material 202 is provided. In one or more embodiments, the powder bed 200 can be the powder bed described elsewhere herein (e.g., powder bed 121). In one or more embodiments, the layer of powder material 202 can be a layer of powder material as described elsewhere herein (e.g., powder layer 125). Information regarding the layer of powder material 202 can be obtained by one or more sensors or cameras (not shown) that are operably configured to obtain information regarding the powder bed 200.

[0048] As Figure 2A shown, the layer of powder material 202 is subdivided into a plurality of regions 205a, 205b, 205c, 205d, 205e, 205f, 205g, etc. Although the plurality of regions 205 are shown as a grid, the regions need not be subdivided into a grid. For example, the plurality of regions 205 can be square, rectangular, circular, triangular, or other geometric or non - geometric shapes. In some embodiments, the plurality of regions 205 are of equal size or approximately equal size. In other embodiments, the plurality of regions 205 are of different sizes. Additionally, although the layer of powder material 202 is shown in Figure 2B from a top - down perspective, the plurality of regions 205 are not limited to two - dimensional areas. Instead, each region 205 can be a three - dimensional voxel having a volume. For example, the depth 208a of the region volume can be the depth of the region in a particular slice of the powder material 202 being scanned, as shown by the dashed line of region 205a in Figure 2C .

[0049] Each of the plurality of blocks 205 has an energy distribution associated with each block. The energy distribution is a representation of the scan performed by the laser beam at the block. These corresponding energy distributions correspond to the portions of the build component to be fused in the respective block regions. These energy distributions may vary from block to block or may be the same. For example, as Figure 2D shown, blocks 205a and 205b have the same energy distribution, block 205c has an energy distribution different from that of blocks 205a, 205b, blocks 205d and 205g have further energy distributions, and blocks 205e, 205f do not have an associated energy distribution, which means that no fusion will occur on these blocks.

[0050] In one or more embodiments, in a shaped laser beam, the energy distribution associated with the laser beam can be configured such that the energy level can be adjusted three-dimensionally along the respective block 205. This laser beam energy distribution represents the power density of the laser beam applied to the block 205 over time. In other words, the laser beam source can be tuned to produce a laser beam that is applied to a specific block at a specific power in the form of pulses at specific positions on the block and is tuned to penetrate to a depth that matches the energy distribution of the block. As Figure 2D shown, as the laser beam moves through the block, the energy distribution of the beam can vary such that the laser beam penetrates the block 205 at different positions within the block plane and penetrates to different depths according to the energy distribution. The depth to which the laser beam penetrates can be based on a continuous increase and decrease in the power (i.e., energy flux) applied to the block surface. For example, in zone 210a, the energy flux level is zero. Thereafter, the laser beam scan continues through the block with increasing power in regions 210b, 210c, thereby increasing the energy flux applied to the block and increasing the heating penetration of the powder material. When each successive zone is applied to the same region of the powder material, the energy flux level (e.g., laser beam intensity) can be increased, which in turn can increase the temperature of the powder material. Thereafter, in zone 210d, the power is reduced, and the reduced energy flux results in less penetration of the powder layer. The power of the laser beam is continuously adjusted at zones 210e, 210f, 210g to match the energy distribution associated with the block.

[0051] In one or more embodiments, the laser beam energy distribution can be configured to preheat the powder material before heating the powder to melting, thermal fluctuations. Thus, the resulting thermal stress can be reduced.

[0052] Figure 3is a flowchart of an exemplary method 300 for additive manufacturing of a build in an L-PBF apparatus as disclosed herein. Referring first to step 305, method 300 includes depositing a layer of powder material in a powder bed. For example, the layer of powder material can be deposited by a depositor. Additionally, the powder layer can be subdivided into a plurality of blocks (i.e., portions or regions of the build layer), each block having a width, length, and depth. At step 310, a laser beam source is configured to generate a laser beam. The laser beam includes an associated beam energy distribution, which can be adjusted by a beam shaping component, step 315.

[0053] Thereafter, method 300 proceeds to obtain information about the powder material layer, the information including the plurality of blocks of the layer and a block energy distribution associated with each of the blocks, step 320. In one or more embodiments, a processing order for each of the plurality of blocks is determined. For example, the block processing order can be determined by optimizing the block processing order to generate a build having a desired residual stress or microstructure at a particular block. In one or more embodiments, the processing order of the plurality of blocks takes into account the energy distribution of adjacent blocks.

[0054] At step 325, method 300 controls the beam shaping component to adjust the beam energy distribution to correspond to the block energy distribution of a first block of the plurality of blocks, thereby obtaining a first beam energy distribution. Thereafter, at step 330, a laser beam pulse having the first beam energy distribution is applied to the first block to fuse a portion of the build corresponding to the first block. For example, the laser beam pulse can be applied at the first block by scanning the laser beam across the block in a horizontal plane of the block. In some embodiments, after applying the pulse for a period of time, the laser beam pulse can be turned off, and then the laser beam spot can be moved to a different location in the block according to the first block energy distribution, and the laser beam pulse can be applied again. In one or more embodiments, the laser beam pulse is fixed at the beam spot on the block. In one or more embodiments, the laser beam pulse can have some slight movement around the beam spot at the block. In one or more embodiments, the application of the laser beam pulse is performed in view of the shape of the block to be fused. For example, the laser beam pulse can be applied to the perimeter of a circular block before applying the laser beam inside the block.

[0055] Optionally, at step 335, method 300 continues by measuring the temperature of the first block by a sensor after the controller applies the laser beam pulse to the first block. Based on the temperature information, the laser beam pulse can be adjusted to optimize the fused portion of the build. Optionally, at step 340, method 300 can include capturing an image of the first block by a camera after the laser beam pulse has been applied to the first block. By capturing the image, the progress of the build can be viewed and possible fusion errors can be inspected.

[0056] Thereafter, at step 345, the beam shaping component can be controlled to adjust the beam energy distribution to correspond to the block energy distribution of the second block among the plurality of blocks, thereby obtaining a second beam energy distribution. In one or more embodiments, the second beam energy distribution is different from the first beam energy distribution. At step 350, method 300 applies a laser beam pulse having the second beam energy distribution to the second block to fuse a portion of the build corresponding to the second block.

[0057] The foregoing description is provided to enable a person skilled in the art to practice the various aspects described herein. Various modifications to these exemplary embodiments presented throughout this disclosure will be readily apparent to those skilled in the art, and the concepts disclosed herein can be applied to other support structures and systems and methods for removing support structures. Accordingly, the claims are not intended to be limited to the exemplary embodiments presented throughout this disclosure, but should be accorded the full scope consistent with the claim language. All structural and functional equivalents of the elements of the exemplary embodiments described throughout this disclosure that are known or later become known to a person of ordinary skill in the art are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element shall be construed under the provisions of 35 U.S.C. § 112(f) or similar laws of the applicable jurisdiction, unless the element is expressly recited using the word "means" or, in the case of a method claim, the element is recited using the words "for step".

Claims

1. An apparatus for additive manufacturing of a building component, comprising: A powder bed depositor configured to deposit a layer of powder material in a powder bed; A laser beam source configured to generate a laser beam; A beam shaping component configured to adjust the energy distribution of the laser beam to obtain a beam energy distribution; And A controller configured to: Obtain information about the powder material layer, the information including a plurality of blocks of the layer and a block energy distribution associated with each of the blocks; Control the beam shaping component to adjust the beam energy distribution to correspond to the block energy distribution of a first block among the plurality of blocks, thereby obtaining a first beam energy distribution; Apply a laser beam pulse having the first beam energy distribution to the first block to fuse a part of the building component corresponding to the first block; Control the beam shaping component to adjust the beam energy distribution to correspond to the block energy distribution of a second block among the plurality of blocks, thereby obtaining a second beam energy distribution, wherein the second beam energy distribution is different from the first beam energy distribution; and Apply a laser beam pulse having the second beam energy distribution to the second block to fuse a part of the building component corresponding to the second block.

2. The apparatus according to claim 1, wherein the block energy distribution includes one or more parameters.

3. The apparatus according to claim 2, wherein the one or more parameters at least include length, width, depth, power density, or time.

4. The apparatus according to claim 1, wherein the first beam energy distribution and the second beam energy distribution have different power densities with the change of time.

5. The apparatus according to claim 1, wherein a part of the first block and a part of the second block overlap.

6. The apparatus according to claim 1, further comprising a sensor configured to measure the temperature of the first block after the controller applies the laser beam pulse to the first block.

7. The apparatus according to claim 1, further comprising a camera configured to capture an image of the first block after the controller applies the laser beam pulse to the first block.

8. The apparatus according to claim 1, further comprising a steering system having the laser beam source.

9. The device according to claim 1, wherein The block energy distribution associated with each of the plurality of blocks includes an energy distribution based on the geometry of the building component.

10. The apparatus according to claim 9, wherein the geometry of the building component includes the geometry of the edge of the building component.

11. The apparatus according to claim 1, wherein the block energy distribution associated with each of the blocks includes an energy distribution based on different melting depths of the powder material in the block.

12. The apparatus according to claim 1, wherein the block energy distribution associated with each of the blocks includes an energy distribution that changes with time.

13. The apparatus according to claim 12, wherein, The energy distribution that changes with time includes a melting period and at least a preheating period or a post-heating period.

14. The apparatus according to claim 1, wherein, The block energy distribution associated with each block in the block includes an energy distribution based at least on the residual stress of the block, the microstructure of the block, or the velocity of the pulse.

15. A method for additive manufacturing of a workpiece, comprising: Depositing a layer of powder material in a powder bed; Obtaining information about the layer of powder material, the information including a plurality of blocks of the layer and a block energy distribution associated with each block in the blocks; Controlling a beam shaping component to adjust the beam energy distribution associated with a laser beam to correspond to the block energy distribution of a first block among the plurality of blocks, thereby obtaining a first beam energy distribution; Applying a laser beam pulse having the first beam energy distribution to the first block to fuse a portion of the workpiece corresponding to the first block; Controlling the beam shaping component to adjust the beam energy distribution associated with the laser beam to correspond to the block energy distribution of a second block among the plurality of blocks, thereby obtaining a second beam energy distribution, wherein the second beam energy distribution is different from the first beam energy distribution; And Applying a laser beam pulse having the second beam energy distribution to the second block to fuse a portion of the workpiece corresponding to the second block.

16. The method according to claim 15, wherein the block energy distribution includes one or more parameters.

17. The method according to claim 16, wherein the one or more parameters include at least one or more of length, width, depth, power density, or time.

18. The method according to claim 15, wherein the first beam energy distribution and the second beam energy distribution have different power densities with respect to changes over time.

19. The method according to claim 15, wherein a portion of the first block and a portion of the second block overlap.

20. The method according to claim 15, further comprising determining a processing order for each block among the plurality of blocks.

21. The method according to claim 15, further comprising determining the shape of the laser beam to be applied to each block among the plurality of blocks.

22. The method according to claim 15, wherein, The block energy distribution associated with each block in the plurality of blocks includes an energy distribution based on the geometry of the workpiece.

23. The method according to claim 15, further comprising determining the size of each block among the plurality of blocks.

24. The method according to claim 15, further comprising determining the beam velocity of the laser beam to be applied to each block among the plurality of blocks.

25. A non-transitory computer-readable medium storing computer-executable instructions executable by a processor for additive manufacturing of a workpiece to: Deposit a layer of powder material in a powder bed; Obtain information about the layer of powder material, the information including a plurality of blocks of the layer and a block energy distribution associated with each block in the blocks; Control a beam shaping component to adjust the beam energy distribution associated with a laser beam to correspond to the block energy distribution of a first block among the plurality of blocks, thereby obtaining a first beam energy distribution; Apply a laser beam pulse having the first beam energy distribution to the first block to fuse a portion of the build corresponding to the first block; Control the beam shaping component to adjust the beam energy distribution associated with the laser beam to correspond to the block energy distribution of a second block among the plurality of blocks, thereby obtaining a second beam energy distribution, wherein the second beam energy distribution is different from the first beam energy distribution; And Apply a laser beam pulse having the second beam energy distribution to the second block to fuse a portion of the build corresponding to the second block.

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