In-situ welding pool spectral radiation process characterization

Abstract

Printers and methods for additive manufacturing constructs may include a camera and a spectrometer to obtain spectral information and optical information from a region of molten material to determine a defect condition based on an evaluation of the processed spectral information or optical information. A processor or computer may process the obtained optical information and determine defect conditions during the additive manufacturing process. The obtained spectral information and optical information may be areas of molten material, molten pools, and pasty zones. The printer and method may include a controller configured to modify process parameters to shape a weld puddle to obtain a desired effective absorptivity of a portion of the weld puddle to increase the effective absorptivity, e.g., relative to an absorptivity of a surface of a powder or material deposited by the depositor, to obtain a desired effective absorptivity of a portion of the weld puddle, e.g., relative to an absorptivity of a surface of the powder or material deposited by the depositor. And maintaining an acceptable temperature of the weld pool during the additive manufacturing process.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 379,554, filed on October 14, 2022, entitled “In-Situ Melt Pool Broad Spectrum Radiation Process Characterization and Monitoring for Transient Elemental State and Composition Changes,” and U.S. Provisional Application Serial No. 63 / 448,641, filed on February 27, 2023, entitled “In-Situ Melt Pool Broad Spectrum Radiation Process Characterization and Monitoring for Transient Elemental State and Composition Changes,” the disclosures of which are incorporated herein by reference in their entireties. Technical Field

[0003] The present disclosure relates generally to additive manufacturing and, more particularly, to obtaining spectral and optical information and determining defects during additive manufacturing of a build part based on evaluating the processed spectral and / or optical information. Background Art

[0004] Additive manufacturing (AM) systems, devices and methods can produce metal or non-metal structures (referred to as build parts) with complex geometries, including shapes that are difficult or impossible to create using conventional manufacturing processes. AM technology is used to create build parts layer by layer (i.e., slice by slice). Each layer or slice can be formed by depositing a layer of material (such as metal or non-metallic powder) and melting and / or cooling the area or region of material that coincides with the cross-section of the build part in that layer. The process can be repeated to form the next slice of the build part, and so on. Because each layer is deposited on the previous layer, AM can be likened to forming a structure piece by piece and allows the formation of structures that were previously impossible to form using traditional machining (i.e., subtractive manufacturing) techniques.

[0005] The build should conform to the required printing parameters, such as the desired shape, desired material density, desired mechanical properties, etc. However, the build often does not completely conform to the desired properties. In some cases, the lack of consistency may require post-processing techniques (such as grinding, filing, etc.) to correct the shape of the build, which may increase production costs. In some cases, the build cannot be repaired or fixed and must be discarded, which can reduce yield and significantly increase production costs. Summary of the Invention

[0006] In the present disclosure, it is recognized that detecting physical properties and states in the process (such as transient element states and temperature changes) during additive manufacturing processes (such as direct metal laser melting (DMLM), powder bed fusion (PBF), selective laser melting (SLM), etc.) can be used to determine defect conditions that may lead to defects or are themselves defects. For example, keyholing is a condition that may occur when the laser is scanned across the powder bed, in which gases in the melting process form a deep cavity in the molten pool. Keyholes may cause defects in the build part caused by bubbles of gas being trapped in the solidified material. Keyholes may be a defect condition that can be detected. Similarly, trapped bubbles themselves may be defect conditions that can be detected. If a defect condition is detected, the process can, for example, modify process parameters to reduce or eliminate the defect condition. Several aspects of apparatus and methods in AM are disclosed more fully below. The following summary of one or more aspects of the present disclosure is presented to provide a basic understanding of these aspects. This summary is not an extensive overview of all contemplated aspects and is neither intended to identify key or important elements nor to describe the scope of any or all aspects. Its purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0007] Various embodiments disclosed herein are apparatus and methods for additive manufacturing. In one aspect, the method includes applying an energy beam to melt a region of material to form a molten pool (the molten pool cools to form a portion of a build part), obtaining spectral information from the region, processing the spectral information to obtain processed spectral information, obtaining an assessment based on the processed spectral information, and determining a defect condition of the additive manufacturing based on the assessment.

[0008] In one or more embodiments, the method includes depositing a material onto a build plate, and the material includes a powder.

[0009] In one or more embodiments, the method includes obtaining optical information from the region, processing the optical information to obtain processed optical information, and performing an evaluation based on the processed optical information.

[0010] In one or more embodiments, the method for obtaining optical information includes controlling a camera to perform optical imaging at a first port with a first field of view of a region of the material, and the method for obtaining spectral information includes controlling a spectrometer to perform spectroscopy at a second port with a second field of view of the region of the material. The first field of view and the second field of view may be the same or different.

[0011] In one or more embodiments, the method of obtaining spectral information includes receiving backscattered radiation from the region.

[0012] In one or more embodiments, the method of obtaining spectral information further includes filtering the backscattered radiation to obtain filtered backscattered radiation.

[0013] In one or more embodiments, the method includes shielding the spectrometer from reflected laser power.

[0014] In one or more embodiments, the weld pool includes a mushy region, mushy region information is obtained from the region, the mushy region information is processed, and further evaluation is performed based on the mushy region information.

[0015] In one or more embodiments, the mushy zone information includes at least temperature information, temperature gradient, solidification rate, or shape information.

[0016] In one or more embodiments, the mushy area includes a slack area and a fragile area, and the mushy area information includes a ratio of a length of the slack area to a length of the fragile area.

[0017] In one or more embodiments, the evaluation includes characteristics of the weld puddle, and the characteristics of the weld puddle include keyhole information or at least size, shape, temperature, or temperature gradient. Shape includes depth, length, width, circumference, area, or volume.

[0018] In one or more embodiments, the method includes modifying process parameters of the additive manufacturing based on the defect condition.

[0019] In one or more embodiments, the method includes adjusting process parameters during additive manufacturing of the build part to maintain an acceptable temperature of the weld puddle.

[0020] In one or more embodiments, the energy beam comprises a laser beam, and the process parameters comprise at least laser power, hatch spacing, scanning speed, beam profile of the laser beam, beam size of the laser beam, or beam shape of the laser beam.

[0021] In one or more embodiments, the laser power is adjusted and at least the hatch spacing, the scanning speed, the beam distribution or the beam shape is adjusted.

[0022] In one or more embodiments, the spectral information includes at least spectral distribution or spectral intensity.

[0023] In one or more embodiments, the method includes determining a temperature distribution or a physical state of at least the weld pool or the mushy zone based on the spectral distribution or the spectral intensity.

[0024] In one or more embodiments, the processed spectral information is a change in spectral intensity value during additive manufacturing of the building block. The spectral intensity may include hydrogen spectral intensity, water vapor spectral intensity, or magnesium spectral intensity.

[0025] In one or more embodiments, the method of obtaining spectral information includes performing spectroscopy on backscattered radiation from the region.

[0026] In one or more embodiments, the method includes applying an energy beam to melt a material to form a weld pool (which cools to form a portion of a build part), obtaining spectral information from the weld pool, and adjusting process parameters based on the spectral information to shape the weld pool to obtain a desired effective absorptivity of a portion of the weld pool, for example, to increase the effective absorptivity relative to the absorptivity of a surface of a powder or material deposited by a depositor.

[0027] In one or more embodiments, the spectral information includes at least the intensity, depth, length, width, circumference, area, or volume of the reflected laser light.

[0028] In one or more embodiments, the method includes applying an energy beam to melt material to form a weld pool (which cools to form a portion of a build part), the weld pool including a mushy zone, obtaining mushy zone information of the mushy zone, and modifying process parameters based on the mushy zone information.

[0029] In one or more embodiments, the method includes applying an energy beam to melt a material to form a weld pool (the weld pool cools to form a portion of a build part), the weld pool including a mushy zone, obtaining mushy zone information of the mushy zone, processing the mushy zone information to obtain processed mushy zone information, obtaining an assessment based on the processed mushy zone information, and determining a defect condition of the additive manufacturing based on the assessment.

[0030] In one or more embodiments, the printer includes a depositor configured to deposit material; an energy beam source configured to generate an energy beam configured to melt a region of material to form a weld pool that cools to form a portion of a build part; a first device configured to obtain spectral information from the region; and a processor or computer in communication with the first device and configured to process the spectral information to obtain processed spectral information, perform an evaluation based on the processed spectral information, and determine a defect condition for additive manufacturing based on the evaluation.

[0031] In one or more embodiments, the depositor is configured to deposit material onto the build plate, the material comprises a powder, and the printer comprises a deflector configured to apply an energy beam to an area of the material.

[0032] In one or more embodiments, the printer includes a second device configured to obtain optical information from the area, the processor or computer is further configured to process the optical information to obtain processed optical information, and further perform the evaluation based on the processed optical information.

[0033] In one or more embodiments, the spectral information includes backscattered radiation received from the region.

[0034] In one or more embodiments, the printer includes a filter configured to filter the backscattered radiation to obtain filtered backscattered radiation.

[0035] In one or more embodiments, the first device includes a spectrometer and the second device includes a camera.

[0036] In one or more embodiments, the camera is coupled to a first port of the printer and the spectrometer is coupled to a second port of the printer.

[0037] In one or more embodiments, a spectrometer and a camera are coupled to the structure.

[0038] In one or more embodiments, the energy beam source includes a laser, and the printer includes a shield coupled to the structure and configured relative to the spectrometer and the laser to prevent reflected power of the laser from damaging the spectrometer.

[0039] In one or more embodiments, a camera is coupled to a first port of the device and a spectrometer is coupled to a second port of the device. The device is coupled to a printer, and the device is a housing or an optical instrument.

[0040] In one or more embodiments, the optical information includes mushy area information of the mushy area.

[0041] In one or more embodiments, the printer includes a controller configured to modify a process parameter based on the evaluation.

[0042] In one or more embodiments, the controller is further configured to modify process parameters such that an acceptable temperature of the weld puddle is maintained during additive manufacturing of the build part.

[0043] In one or more embodiments, the processor or computer is further configured to determine a temperature distribution or state of at least the mushy zone based on the spectral distribution or spectral intensity.

[0044] In one or more embodiments, the printer includes a depositor configured to deposit material; an energy beam source configured to generate an energy beam configured to melt a region of material to form a weld pool that cools to form a portion of a build part; a first device configured to obtain spectral information from the region; and a controller configured to adjust process parameters based on the spectral information to shape the weld pool to obtain a desired effective absorptivity of a portion of the weld pool, for example, to increase the effective absorptivity relative to the absorptivity of a surface of a powder or material deposited by the depositor.

[0045] In one or more embodiments, the spectral information is from the weld puddle and includes at least the intensity, depth, length, width, perimeter, area, or volume of the reflected laser light.

[0046] In one or more embodiments, a printer includes a depositor configured to deposit material; an energy beam source configured to generate an energy beam configured to melt a region of material to form a weld puddle that cools to form a portion of a build part; a first device configured to obtain information of the weld puddle; and a controller configured to modify process parameters based on the information to maintain an acceptable temperature of the weld puddle during additive manufacturing of the build part.

[0047] In one or more embodiments, the printer includes a depositor configured to deposit material; an energy beam source configured to generate an energy beam, the energy beam configured to melt a region of material to form a weld pool, the weld pool cools to form a portion of a build part, the weld pool including a mushy zone; a first device configured to obtain mushy zone information from the mushy zone; and a controller configured to modify process parameters based on the mushy zone information.

[0048] In one or more embodiments, the printer includes a depositor configured to deposit material; an energy beam source configured to generate an energy beam, the energy beam configured to melt a region of material to form a weld pool, the weld pool cools to form a portion of a build part, the weld pool including a mushy zone; a first device configured to obtain mushy zone information from the mushy zone; and a processor or computer in communication with the first device and configured to process the mushy zone information to obtain processed mushy zone information, perform an evaluation based on the processed mushy zone information, and determine a defect condition for additive manufacturing based on the evaluation.

[0049] Other aspects will be readily apparent to those skilled in the art from the following detailed description, wherein only a few exemplary embodiments are shown and described by way of illustration. As will be appreciated by those skilled in the art, the concepts described herein can be applied to other and different embodiments, and the several details can be modified in various other respects, all without departing 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

[0050] Various aspects of the present technology will be presented in the detailed description by way of example and not limitation in the appended claims and accompanying drawings. In the following description, like components are labeled with like numerals throughout the specification and drawings. The drawings are not necessarily drawn to scale, and some drawings may be shown exaggerated or generalized for clarity and conciseness.

[0051] Figures 1A-1D Respective side views of an example powder bed fusion (PBF) system useful with aspects of the present disclosure during different stages of operation according to aspects of the present disclosure are shown.

[0052] Figure 1E A functional block diagram of a PBF system according to aspects of the present disclosure is shown.

[0053] Figure 2 An example PBF apparatus that may be used in a 3-D printer is shown, the apparatus including a radiation collector for obtaining radiation and a controller for modifying one or more process parameters in closed-loop control.

[0054] Figure 3 A side cross-sectional view of a PBF system including a radiation collector is shown.

[0055] Figure 4 A perspective front view of a PBF system including first and second devices is shown.

[0056] Figure 5 An apparatus of a PBF system is shown including a plurality of devices connected to ports of the apparatus.

[0057] Figure 6 A PBF system including a melt pool of material regions and a mushy zone is shown.

[0058] Figure 7 A mushy region including a relaxed region and a fragile region is shown.

[0059] Figure 8 An example keyhole pattern is shown.

[0060] Figure 9 Example spectral intensities obtained and processed from a region of melted powder are shown.

[0061] Figure 10 The thermal radiation and spectral intensity after acquisition and processing are shown.

[0062] Figure 11 An example of a computer coupled to a spectrometer is shown.

[0063] Figure 12 A manufacturing method including obtaining and processing spectral information, obtaining an assessment, and determining defect conditions is shown.

[0064] Figure 13 A manufacturing method is shown that includes obtaining spectral information and modifying / adjusting process parameters based on the spectral information.

[0065] Figure 14 A manufacturing method is shown that includes obtaining mushy region information and modifying / adjusting process parameters based on the mushy region information.

[0066] Figure 15 A manufacturing method including obtaining and processing mushy region information, obtaining an assessment, and determining defect conditions is shown. DETAILED DESCRIPTION

[0067] In additive manufacturing, solutions have been developed to detect defects in build parts. However, all of these solutions require the build part to be formed first, and then the solution is used to detect defects within the completed build part. As a result, the build part (e.g., structure, component) may be defective and unacceptable for use, resulting in cost, waste, and lost customer production time when the defective build part is discarded.

[0068] To overcome the aforementioned issues associated with finished builds containing defects, it is desirable to prevent or mitigate defects occurring within builds during additive manufacturing by determining the defect profile of the additive manufacturing process in situ (i.e., in real time). In various embodiments, determining the defect profile can be based on an evaluation of acquired and / or processed spectral and / or optical information.

[0069] In embodiments, process parameters can be modified in situ (i.e., in real time) to mitigate or correct defects within a component. An infrared (IR) camera and a spectrum analyzer (e.g., a spectrometer), alone or in combination, can be used to monitor the weld pool temperature and its spectral radiation characteristics, for example, within a wavelength range of 10 nm to 10 μm. However, the wavelength range can include wavelengths less than 10 nm and / or greater than 10 μm. The camera can be an infrared (IR) camera, a thermal imager, an optical camera, or the like. For example, an IR camera can obtain transient temperature characteristics of the weld pool (i.e., the weld pool and the mushy zone) and monitor the region of melted powder, which can include the weld pool (i.e., the weld pool and the mushy zone) and the area surrounding the weld pool, while additively manufacturing the component. Furthermore, the IR camera can obtain quality process control variables for dimensional measurement and characterization (width and length) of the weld pool and the mushy zone to reduce thermal deformation and cracking at the micro and meso levels. The spectrum analyzer can be, for example, a spectrometer. The spectrometer can obtain spectral information from ultraviolet (UV) to near-infrared (NIR). Spectrometers can provide laser welding process monitoring and characterization via NIR spectral radiometry, including:

[0070] i) In-situ monitoring of weld pool conditions via phase change (solid to liquid, liquid to vapor), composition (Mg, Al, etc.) and temperature;

[0071] ii) Melt pool size via spectral intensity of one or more components, e.g. for Mg at wavelengths of 279 to 280 nm).

[0072] For known material alloys and laser parameters, changes in weld pool temperature or spectral intensity peaks can be acquired and characterized for known defect types. These defects can include, for example, porosity (e.g., lack of fusion, keyholes), micro- / meso-level weld cracking, undesirable microstructure, increased residual stresses, elemental composition variations, and undesirable bulk material properties. In various embodiments, active, controlled monitoring of the laser process during the early stages of keyhole formation can allow for mitigation or correction, which can improve overall process energy efficiency by reducing laser power, thereby significantly reducing overall electrical energy consumption. Meso-level finite element weld pool simulations can be performed and used to parametrically study and correlate transient thermal responses across a range of laser and process parameters. Machine learning algorithms can be developed and used to characterize and learn thermal and spectral signatures in real time to monitor for undesirable properties. Machine learning process parameter relationships can be developed in conjunction with in-situ sensor measurements (i.e., acquired spectral and / or optical information) and can provide feedback control of the build process by actively adjusting process parameters (e.g., laser power, scan speed, beam profile, etc.). The combination of real-time process monitoring (e.g., melt pool and mushy zone dimensions, etc.) and learned weld pool states can allow the disclosed methods, systems, and apparatus to mitigate defects before they occur. Measurements of the size and temperature (maximum temperature and temperature gradient) of the melt pool and mushy zone can be used to confirm finite element analysis (FEA) simulations to improve subsequent predictions. In addition, a high-speed IR camera (e.g., a camera with greater than 200 frames per second (fps)) with particle tracking software can be used to characterize and track weld pool spatter.

[0073] A three-dimensional (3-D) printer, including a powder bed fusion (PBF) system and a PBF device disclosed below, may include a depositor configured to deposit multiple layers of material (e.g., powder) onto a build plate forming a powder bed. The printer may include an energy beam source configured to generate an energy beam that is selectively applied to one or more surfaces of powder associated with a powder layer to melt an area of the powder such that the area of the powder forms a molten pool. When the energy beam moves away from the area or is no longer applied to the area, the molten pool cools to form a mushy region, which is typically composed of part liquid and part solid, which typically drags the molten pool as the energy beam is scanned across the powder layer. After a period of time, the mushy region further cools to a temperature at which it solidifies to form a portion of a build part. As used herein, the term "weld pool" includes the molten pool and the mushy region.

[0074] The printer may include a plurality of ports or structures for coupling thereto a first device (such as a spectrometer) and a second device (such as a camera) to obtain spectral and optical information during the additive manufacturing of a build part. The printer may include a processor or computer for processing (i.e., computing data, performing logical operations on the data, and all known processor functions) the obtained spectral and optical information during the additive manufacturing of the build part, and for performing an evaluation based on the processed spectral and / or processed optical information, and based on the evaluation, determining defect conditions during the additive manufacturing process of forming the build part. The processor or computer may process mushy region information obtained from the camera and / or spectrometer to perform an evaluation based on the processed mushy region information, and based on the evaluation, determine defect conditions during the additive manufacturing process of forming the build part. The camera and spectrometer may obtain information, such as spectral and optical information, from the region of powder, the melt pool, and the mushy region. The printer may include a controller configured to modify / adjust one or more process parameters during the additive manufacturing of the build part based on the spectral information, the obtained optical information, the processed spectral information, and / or the processed optical information obtained from the region of powder, the melt pool, and the mushy region. The controller can adjust one or more process parameters based on information (e.g., information obtained from regions of the powder, the molten pool, and the mushy zone during additive manufacturing of the build part and / or processed information). For example, the controller can adjust one or more process parameters to shape the weld pool so as to achieve a desired effective absorptivity of a portion of the weld pool, such as to increase the effective absorptivity relative to the absorptivity of a surface of the powder or material deposited by the depositor. The controller can adjust one or more process parameters to maintain an acceptable temperature of the molten pool during additive manufacturing of the build part.

[0075] Figures 1A-1D 1 and 2 illustrate respective side views of an example of a PBF system 100 that may be used with aspects of the present disclosure, including a 3-D printer, during different stages of operation. As described above, Figure 1A The specific embodiment shown in FIG. 1 is one of many suitable examples of PBF systems employing the principles of the present disclosure. It should also be noted that Figure 1AElements of Figure 1-D and other figures in this disclosure are simplified and not necessarily drawn to scale, but may be drawn larger or smaller and / or with reduced detail to better illustrate the concepts described herein. PBF system 100 may include: a depositor 101, which may deposit each powder layer 125; an energy beam source 103, which may generate an energy beam 127; a deflector 105, which may direct or redirect the energy beam to melt powder 117; and a build plate 107, which may support one or more build pieces, such as build piece 109. PBF system 100 may also include a build base plate 111, which is positioned within the powder bed container and between powder bed container walls 112. Build base plate 111 may gradually lower build plate 107 so that depositor 101 can deposit the next layer. In some examples, all of the above-disclosed features of the PBF system may reside in a chamber 113, which may surround other features, thereby protecting them from atmospheric conditions (e.g., providing the features in an inert environment), temperature regulation, and mitigating contamination risks. The depositor 101 may include a hopper 115 that holds powder 117 such as metal (eg, alloy) powder or non-metal (eg, plastic or thermoplastic polymer) powder, and a leveler 119 that may level the top of each layer of deposited powder.

[0076] specifically refer to Figure 1A , this figure shows PBF system 100 after a piece of build part 109 has been fused by energy beam 127 but before the next layer of powder is deposited. In fact, Figure 1A The current state at which time PBF system 100 has deposited and fused a partially completed build in multiple layers to form build 109 is shown. The multiple layers that have been deposited have created a powder bed 121, which includes deposited but unmelted powder.

[0077] Figure 1B PBF system 100 is shown at a stage in which build plate 111 can be lowered by powder layer thickness 123. The lowering of build plate 111 causes build piece 109 and powder bed 121 to drop by powder layer thickness 123, such that the top of the build piece and powder bed is lower than the top of powder bed container wall 112 by an amount equal to the powder layer thickness. For example, in this way, a space having a consistent thickness equal to powder layer thickness 123 can be created above the top of build piece 109 and powder bed 121.

[0078] Figure 1CPBF system 100 is shown at a stage in which depositor 101 is positioned to deposit powder 117 in a space created above a build piece 109 and a top of a powder bed 121 and bounded by powder bed container walls 112. In this example, depositor 101 can move over the defined space while releasing powder 117 from hopper 115. Leveler 119 can level the released powder to form a powder layer 125 having a thickness substantially equal to powder layer thickness 123 (see FIG. Figure 1B ). Thus, the powder in the PBF system may be supported by a powder material support structure, which may include, for example, build plate 107, build base 111, build piece 109, wall 112, etc. It should be noted that the thickness of the illustrated powder layer 125 (i.e., powder layer thickness 123 ( Figure 1B )) is greater than the reference above Figure 1A The actual thickness of the example in question comprises 150 previously deposited layers.

[0079] Figure 1D The figure shows a state in which after deposition of the powder layer 125 ( Figure 1C ) The PBF system 100 is shown in a stage where the energy beam source 103 generates the energy beam 127 and the deflector 105 applies the energy beam to melt the next piece in the build part 109. In various exemplary embodiments, the energy beam source 103 may be an electron beam source, in which case the energy beam 127 constitutes an electron beam. The deflector 105 may include deflection plates that may generate an electric or magnetic field that selectively deflects the electron beam to cause the electron beam to scan across the area designated to be melted. In various embodiments, the energy beam source 103 may be a laser beam source, in which case the energy beam 127 is a laser beam. The deflector 105 may include an optical system that uses reflection and / or refraction to manipulate the laser beam to scan the area / region on the selected powder layer to be melted. In various embodiments, the deflector 105 may include one or more gimbals and actuators that may rotate and / or translate the energy beam source to position the energy beam. In various embodiments, the energy beam source 103 and / or the deflector 105 can modulate the energy beam, for example, turning the energy beam on and off as the deflector scans so that the energy beam is applied only to appropriate areas / regions of the powder layer. For example, in aspects of the present disclosure, the energy beam can be modulated by a digital signal processor (DSP). The deflector can include any system known in the art, such as a galvanometer scanner or a galvanometer and / or a raster scanner. It should be noted that although a single energy beam source 103 and / or deflector 105 is shown, aspects of the present disclosure can be used for and can include systems having multiple energy sources and / or one or more deflectors.

[0080] like Figure 1DAs shown, most of the melting of powder layer 125 occurs in the area of the powder layer that is on top of the previous piece, ie the previously melted powder. An example of such an area is the surface of build part 109. Figure 1D Melting of the powder layer in the slab occurs over previously fused layers of the material representing build part 109. However, in certain areas of powder layer 125, melting may occur on top of loose powder—that is, over powder that was not fused, either inadvertently or otherwise. For example, if the patch area is larger than the previous patch area, at least a portion of the patch area will be formed over the loose powder. Applying the energy beam to melt areas of powder over the loose powder can be problematic. Melted powder is liquefied and typically denser than loose powder. The melted powder can infiltrate the loose powder, causing build part 109 to sag, curl, or otherwise deform undesirably. Because loose powder can have low thermal conductivity, melting powder in overhanging areas can result in higher temperatures than expected because low thermal conductivity can reduce the ability to conduct heat away from the fused powder. Higher temperatures in these areas lead to higher residual stresses after cooling, often resulting in a poorer quality build part. In some cases, dross can form in the overhanging areas, leading to undesirable surface roughness or other quality issues.

[0081] Figure 1E A functional block diagram is shown that may be used with the disclosed 3-D printer and PBF system and apparatus according to aspects of the present disclosure. In one aspect of the present disclosure, a control device and / or element (including computer software) may be coupled to the PBF system 100 to control one or more components or process parameters within the PBF system 100. Such a device may be a computer 150, which may include one or more process parameters 216 that may facilitate control of the PBF apparatus 100. The computer 150 may communicate with the PBF system 100 and / or other AM systems via one or more interfaces 151 (e.g., a bus system). The controller 214, computer 150, and / or interface 151 are examples of devices that may be configured to implement the various systems, apparatuses, and methods described herein, and which may facilitate control of the PBF system 100 and / or other AM systems. The interface 151 may include an input / output device that allows the controller 214 and / or computer 150 to exchange information with other devices. In some embodiments, the interface 151 may include one or more parallel ports, serial ports, or other computer interfaces.

[0082] In one aspect of the disclosure, computer 150 may include at least one processor 152, memory 154, signal detector 156, digital signal processor (DSP) 158, and one or more user interfaces 160. Computer 150 may include additional components without departing from the scope of the disclosure.

[0083] Computer 150 may include at least one processor 152, which may assist in controlling, processing, and / or operating PBF system 100. Processor 152 may also be referred to as a central processing unit (CPU). Memory 154, which may include read-only memory (ROM) and random access memory (RAM), may provide instructions and / or data to processor 152. A portion of memory 154 may also include non-volatile random access memory (NVRAM). Processor 152 typically performs logical and arithmetic operations based on program instructions stored within memory 154. The instructions in memory 154 may be executable (e.g., executed by processor 152) to implement the functions and methods described herein.

[0084] Processor 152 may include or be a component of a processing system implemented with one or more processors. The one or more processors may be implemented using any combination of general-purpose microprocessors, microcontrollers, digital signal processors (DSPs), floating-point gate arrays (FPGAs), programmable logic devices (PLDs), controllers, state machines, gated logic, discrete hardware components, dedicated hardware finite state machines, or any other suitable entities that can perform computations or other manipulations of information.

[0085] The processor 152 may also include a machine-readable medium for storing software. Software should be broadly interpreted as any type of instruction, whether referred to as software, firmware, middleware, microcode, hardware description language, or other. Instructions may include code (e.g., source code format, binary code format, executable code format, RS-274 instructions (G-code), numerical control (NC) programming language, and / or any other suitable code format). When executed by one or more processors, the instructions cause the processing system to perform the various functions described herein.

[0086] Computer 150 may also include a signal detector 156, which can be used to detect and quantify any signal levels received by computer 150 for use by processor 152 and / or other components of computer 150. Signal detector 156 can detect signals such as energy beam source 103 power, deflector 105 position, build plate 111 height, the amount of powder 117 remaining in depositor 101, leveler 119 position, and other signals. Signal detector 156 can control other components as described herein in addition to or in place of processor 152. Computer 150 may also include a DSP 158 for processing signals received by computer 150 or processor 152. The DSP can be configured to generate instructions and / or instruction packets for transmission to PBF system 100.

[0087] In some aspects, computer 150 may also include a user interface 160. User interface 160 may include a keyboard, a pointing device, and / or a display. User interface 160 may include any element or component that conveys information to a user of computer 150 and / or receives input from the user.

[0088] The various components of the computer 150 can be coupled together via a bus system 151. The bus system 151 can include, for example, a data bus, as well as a power bus, a control signal bus, and a status signal bus in addition to the data bus. The components of the computer 150 can be coupled together or use some other mechanism to receive or provide input from each other.

[0089] Despite Figure 1E Many separate components are shown in FIG, but one or more components may be combined or implemented together. For example, the processor 152 may be used to implement not only the functions described above with respect to the processor 152, but also the functions described above with respect to the signal detector 156, the DSP 158, and / or the user interface 160. In addition, Figure 1E Each component shown in FIG may be implemented using multiple individual elements.

[0090] For example, any combination of an element, any part of an element, or an element can be implemented using one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors can execute software.

[0091] In one or more aspects, the functions described can be implemented using hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, including any media that facilitates transferring a computer program from one place to another. The storage medium can be any available medium that can be accessed by the computer 150. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, compact disc (CD) ROM (CD-ROM) or other optical disc storage, magnetic disk storage or other magnetic storage device, or any other medium that can be used to carry or store the required program code in the form of instructions or data structures and that can be accessed by the computer 150. Disks and optical discs as used herein include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically, while optical discs reproduce data optically with lasers. Therefore, computer-readable media include non-transitory computer-readable media (e.g., tangible media). The RAM may include one or more static random access memories (SRAMs), dynamic random access memories (DRAMs), synchronous dynamic random access memories (SDRAMs), double data rate random access memories (DDR SDRAMs), or other suitable volatile memories. The read-only memories (ROMs) may include one or more programmable read-only memories (PROMs), erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), flash memories, or other types of non-volatile memories.

[0092] Figure 2 An example PBF device 200 is shown as a component of a 3-D printer. In some embodiments, the PBF device 200 is configured to collect radiation from a region of material that is melted by the energy beam to form a portion of a build part and used for process parameter modification via closed-loop control. Figure 3-7 Features that collect radiation from the region of molten material are shown in more detail.

[0093] Figure 2 2. Build plate 201, powder bed 203 within powder bed container wall 204, build piece 205 in powder bed 203, depositor 207, energy applicator 210, controller 214, radiation collector 221, and shielding member 246 are shown. During a recoating cycle (also referred to as a deposition cycle), depositor 207 may deposit a layer of material comprising powder in powder bed 203. Energy beam source 211 is configured to apply an energy beam (e.g., energy beam 127) during a scanning cycle to melt the powder in the deposited layer. Radiation collector 221 is configured to emit radiation from region 305 (e.g., Figure 3 127 is applied to the powder bed 203 and processes the radiation to obtain spectral information and / or optical information. The controller 214 is configured to process the spectral information and / or optical information to obtain processed spectral information and / or processed optical information, obtain an evaluation based on the processed information, and modify one or more process parameters 216 based on the evaluation. Figure 1D ) is selectively applied to the deposited powder layer (401, 402, 405, see Figure 4 ) associated with one or more surfaces of the powder to melt the region of the powder (305, see Figure 3 ) at least a portion of the region 305. Region 305 may include a weld pool 605, which may include a molten pool 620 and a mushy region 610. (See Figure 6 ) The molten pool 620 includes the melted powder (ie, liquid material) within the region 305, and the mushy region 610 includes the cooled melted powder that is typically composed of part liquid material and part solid material.

[0094] The energy applicator 210 may include an energy beam source 211 and a deflector 213 that uses a processor-controlled beam steering system to steer the energy beam across the deposited layers, such as using a galvanometer / mirror system in the case where the energy beam is a laser beam, or using a magnet and / or grid array for generating electric and magnetic fields in the case where the energy beam is an electron beam.

[0095] The radiation collector 221 obtains radiation related to the deposition of layers, the melting of powder materials, the composition of powder materials, tracking interactions, and other conditions within the 3D printer. In various embodiments, the radiation collector 221 is configured to obtain / receive radiation from the region 305, wherein the obtained radiation includes spectral information and optical information. The radiation collector 221 can process the radiation to obtain both spectral information and optical information, or can obtain spectral information or optical information. The radiation collector 221 can include one or more devices (e.g., Figure 4430, 440 in ), which is configured to obtain / receive radiation having spectral information and / or optical information from region 305. The radiation collector 221 can collect radiation that radiates from the surface of the powder bed 203 and strikes a receiving surface of the radiation collector. For example, the radiation collector 221 can include a camera and / or a spectrometer to measure radiation during a printing job. Alternative or additional sensors can be used for similar or different purposes and use different techniques and equipment, and the present disclosure is not limited to collecting radiation with the example sensors disclosed in the radiation collector 221. The radiation collector 221 can collect radiation to determine information about various characteristics of the environment in which the powder bed is located. Other circuits or other components within or external to the radiation collector 221 can use this information to determine characteristics associated with the powder bed 203, for example, including material composition and / or tracking interactions. For example, the UV spectrum can also include other information about the process, such as the frequency response of the scan, the total amount of UV radiation, the composition of the material, and whether contaminants are present (for example, using a spectrum in the UV range), and similar capabilities. As described above, the controller 214 or dedicated processor circuit can extract information from the UV spectrum in various ways. This information can be stored in a memory. The processor or other circuit system can use radiation within these UV frequencies / ranges to determine information associated with relevant portions of the powder bed 203. Using this data, the controller 214 can adjust various configurations and / or printer parameters of the PBF device 200 (e.g., the intensity of the energy beam), for example, in real time during the next expected scan cycle or for a completely independent build process. The radiation collector 221 can be configured to receive radiation in the UV spectrum during a scan cycle. That is, when the energy applicator 210 controls the energy beam source 211 to apply the energy beam, the radiation collector 221 can collect UV radiation, which causes the powder material in one or more deposited layers to fuse and interfere with elements (e.g., powder and other particles). In some embodiments, the radiation collector 221 can be configured to obtain radiation along a path corresponding to the point where the energy beam strikes the surface of the powder bed 203, which can also be referred to as a weld site. For example, the controller 214 can control the movement of the radiation collector 221 so that an unobstructed UV optical path is maintained between the radiation collector 221 and the weld site. In another example, the radiation collector 221 can be connected to the energy applicator 210 such that movement of the energy applicator 210 (e.g., movement of a galvanometer / mirror system in the energy applicator) causes radiation from the weld site (e.g., backscattered radiation) to be diverted toward the radiation collector 221.

[0096] Spectral information may include spectral distribution, electromagnetic radiation, all electromagnetic waves of the electromagnetic spectrum, spectral intensity, thermal radiation from region 305, electron emission from region 305, radiation from electronic state transitions from region 305, and backscattered radiation 320 (see Figure 3 ), where backscattered radiation 320 may include reflected energy such as reflected laser beam energy from region 305. Although various embodiments described herein focus on radiation generated by interacting with a laser beam, those skilled in the art will readily understand how the disclosed principles may be applied to other energy beams, such as electron beams.

[0097] Optical information may include thermal radiation from region 305, electromagnetic radiation, all electromagnetic waves of the electromagnetic spectrum, which may include infrared (IR), near infrared (NIR), visible, and ultraviolet (UV) light, as well as backscattered radiation 320 (see Figure 3 ), where backscattered radiation 320 may include reflected energy such as reflected laser beam energy from region 305.

[0098] Obtaining spectral information and / or optical information may include any or all physical processes for obtaining spectral information or optical information, such as capturing thermal radiation, electromagnetic radiation, all electromagnetic waves of the electromagnetic spectrum and backscattered radiation 320 and / or filtering thermal, electromagnetic and backscattered radiation, and all electromagnetic waves of the electromagnetic spectrum, etc.

[0099] The spectral information and / or optical information can be obtained by, for example, a first device (which can include a camera or a spectrometer) and a second device (which can include a camera or a spectrometer). The camera can include a thermal camera, an optical camera, an IR camera, etc. The spectrometer can include a spectrum analyzer, a spectrometer that performs spectroscopy, etc.

[0100] Processor 152 or computer 150 is coupled to the first device and the second device and is configured to process the spectral information and optical information obtained from the first device and the second device to obtain processed spectral information or processed optical information, perform an evaluation based on the processed spectral information and / or processed optical information, and determine additive manufacturing defect conditions based on the evaluation. Processor 152 or computer 150 can communicate with the first device and the second device wirelessly or by wire. Processing of the spectral information and optical information by processor 152 or computer 150 includes computer processing of data and information of the spectral information and optical information.

[0101] Defects in the AM process (i.e., AM build parts) can include:

[0102] i) defects in the component, such as porosity (caused by keyholes, lack of fusion, etc.), large pores, interlayer weld cracking, microstructural changes, increased residual stresses, changes in elemental composition, changes in material properties, or other defect types;

[0103] ii) conditions that favor defects in the build (e.g., keyholes, faulty subsequent layers, where the width, height or depth of a layer is too large or too small, the surface of a layer has large or small deviations (i.e., undulations); defects in the laser beam, process parameters (e.g., incorrect shape, distribution or spot size, incorrect power of the energy applicator, etc.);

[0104] iii) Defects in the powder bed (e.g. too thick or too thin, grooves and / or ripples in one or more layers of the powder bed).

[0105] Furthermore, drawbacks can include increased build time and material costs due to suboptimal additive manufacturing conditions.

[0106] The evaluation may use the processor 152, the computer 150, or a combination of the processor and the computer to compare the acquired and processed spectra and the processed information to values, standards, criteria, data such as historical data from previous additive manufacturing processes and / or data from the defect cases described above. For example,

[0107] Assessments may include:

[0108] i) An assessment based on whether the difference between the spectral information and the standard is above or below the value or range of the acceptance criteria;

[0109] ii) an assessment based on the difference between the optical information and the standard being above or below a value or range within the acceptance criteria;

[0110] iii) an evaluation based on the ratio of the characteristic value of the melt pool to the value of the standard;

[0111] iv) an evaluation based on the ratio of the characteristic value of the mushy area to the value of the standard;

[0112] v) an evaluation based on changes in spectral intensity values during additive manufacturing of a build part;

[0113] vi) An evaluation of the melt pool to have an acceptable temperature range during additive manufacturing of the build to prevent any defect conditions (ie any of the defects mentioned above).

[0114] The controller 214 is coupled to and in communication with the process parameters 216, the radiation collector 221, the energy beam applicator 210, the computer 150, and the processor 152, and is configured to modify the process parameters based on the evaluation. The process parameters include, for example, laser power, hatch spacing, scan speed, beam profile of the laser beam, beam size of the laser beam, beam shape of the laser beam, or any combination thereof. The controller 214 can also be configured to modify the process parameters so that the temperature of the molten pool is maintained within an acceptable range during the additive manufacturing of the build part. The controller 214 can be configured to adjust the process parameters based on the spectral information to shape the weld pool so as to achieve a desired effective absorptivity of a portion of the weld pool, for example, to increase the effective absorptivity relative to the absorptivity of the surface of the powder or material deposited by the depositor. The controller 214 can be configured to modify the process parameters based on this information to maintain an acceptable temperature (which can include a range of temperatures) of the molten pool during the additive manufacturing of the build part. The controller 214 can be configured to modify the process parameters based on the mushy zone information.

[0115] In some embodiments, as part of or in conjunction with the various features and methods described herein, one or more microcontrollers may be implemented to control any one or combination of the operations described herein (e.g., the operation of the PBF system and / or support removal system and apparatus described herein). Controller 214 includes a CPU, RAM, ROM, a clock and timer, a bus controller, an interface, and an analog-to-digital converter (ADC) interconnected via a bus. The CPU may be implemented as one or more single-core or multi-core processors and receives signals from an interrupt controller and a clock. The clock may set the operating frequency of the entire microcontroller and may include one or more crystal oscillators having a predetermined frequency. Alternatively, the clock may receive an external clock signal.

[0116] The controller 214 can be, for example, a computer processor. For example, the controller 214 can be one or both of the print controller and the processor 152 that references spectral information and optical information (such as radiation). In some embodiments, the controller 214 can be a print controller for controlling basic functions of the PBF device 200 (such as re-coating printer parameters, scan type, scan speed, beam intensity, beam steering, etc.). That is, the controller 214 can issue instructions to direct the energy beam to move across the powder bed in order to print a structure previously modeled using computer-aided design. In some embodiments, the controller 214 can be a processor that performs general printing functions and supervision of the PBF device 200, as well as functions related to control as further described herein. In other embodiments, the processor (e.g., Figure 1E) may be different from the print controller. The two processing elements (e.g., controller 214 and processor 152) may typically communicate via a bus or other line. Such communication enables the print controller to modify one or more printer parameters based on information from the processor. The controller 214 may control the depositor 207 to deposit a layer of material, may control the energy beam source 211 to generate an energy beam, and may control the deflector 213 to scan the energy beam across the deposited layer in a precise manner to obtain the build part 205. Furthermore, in various embodiments, the controller 214 may control the above-described components in the manner described above by using different determined printer parameter values or types and / or by using different determined subsets or combinations of printer parameters to achieve a desired result for the particular printing operation in question (such as managing overhang, improving surface finish quality, optimizing print speed, optimizing an overall combination of these and other operations, etc.).

[0117] Process parameter modifications can include, for example, reducing or increasing hatch spacing, scanning speed, beam distribution of the laser beam, beam size of the laser beam, or beam shape or intensity of the energy beam (such as laser beam intensity), layer thickness, gas flow rate (e.g., the flow rate of the gas across the surface of the powder bed), and other actions described herein.

[0118] In some other embodiments, PBF apparatus 200 is configured for data collection and analysis. For example, during the fabrication of build 205, PBF apparatus 200 can be configured to simultaneously collect data associated with the process status, as well as data associated with build 205 and / or powder bed 203 used in its fabrication (e.g., data regarding the material composition). Such collected data can be used for quality control, such as determining deviations from the material composition. Furthermore, such collected data can be used to adjust printer parameters 216 and / or otherwise configure PBF apparatus 200 for future printing operations, such as by developing mathematical and / or heuristic functions designed to enhance material properties and ensure build process consistency.

[0119] Figure 3 A combined deflector and radiation collector 300 is shown according to various embodiments. An energy beam 327 may be provided (e.g., from an energy beam source such as Figure 2 211 in the region) and is applied to the powder in the region 305 via the scanning optical device 375, forming a welding molten pool 605 (including a molten pool 620 and a mushy region 610). Figure 6 and Figure 7Detailed views of the weld pool are shown in FIG. In this embodiment, the scanning optical device 375 performs the function of a deflector (such as the deflector 213) and can be considered as a deflector. As the energy beam 327 is applied to the powder in the region 305, the backscattered radiation 320 is reflected from the region 305 (e.g., from the weld pool 605) through the focusing optical device 380 and reaches the first device 430 and the second device 440 via the first port 330 and the second port 340, respectively. The first device 430 and the second device 440 may include devices that can process the backscattered radiation 320 to obtain spectral information and / or optical information. In this embodiment, the first device 430, the second device 440, the first port 330, the second port 340, and the focusing optical device 380 perform the function of a radiation collector (such as the radiation collector 321) and can be considered as a radiation collector.

[0120] The focusing optics 380 may include components such as a lens, multiple lenses, and / or mirrors that redirect the backscattered radiation 320 toward the first port 330 and the second port 340, as described below. In this embodiment, the focusing optics 380 and the scanning optics 375 share some optical elements. The focusing optics 380 may additionally include a filter 435 and / or a filter 445 (see FIG. 1 ) that filters the backscattered radiation 320 to obtain filtered backscattered radiation. Figure 4 ). The filter may include an optical filter, a lens, or a lens including a transparent material (such as a UV transparent material). The filter may be coupled to one or more ports of the 3-D printer. For example, the filter may include multiple filters 435, 445.

[0121] In this embodiment, a first device 430 and a second device 440 may be coupled to structure 328. The first device may be coupled to the structure's first port 330 such that spectral information and / or optical information may be obtained by the first device in a first field of view of the melted powder region 305. The second device 440 may be coupled to the structure's second port 340 such that spectral information and / or optical information may be obtained by the second device in a second field of view of the melted powder region 305. The first field of view and the second field of view may include spectral information and optical information. The first and second devices may both be coupled to a single port of a 3-D printer, or the first device may be coupled to a first port of the 3-D printer and the second device may be coupled to a second port of the 3-D printer. In an embodiment, either the first device or the second device may be coupled to a port of the 3-D printer. However, more than two devices may be coupled to the ports of the 3-D printer, or each device may be coupled to each port of the 3-D printer. The 3-D printer may include more than two ports.

[0122] Region 305 may include a weld pool 605 having a molten pool 620 and a mushy zone 610 (see FIG. Figure 6 ). Molten pool 620 includes liquid melted powder within region 305. Mushy region 610 is typically composed of partially liquid melted powder and partially solid material resulting from cooling of the melted powder. The first device includes a camera or a spectrometer. The second device includes a camera or a spectrometer. The camera may include a thermal camera, an optical camera, an IR camera, etc. The spectrometer may include a spectrum analyzer, a spectrometer that performs spectroscopy, etc.

[0123] Figure 4 PBF system 400 is shown, which includes a build plate 407 supporting deposited powder layers 401, 402, 405 (where layers 401 and 402 have been selectively fused in a previous scan), an energy beam source 403 that generates an energy beam 427, and a deflector 404 that scans the energy beam to selectively apply the energy beam to one or more surfaces of the deposited powder layer 405 to melt regions of the powder (305, see Figure 3 ) at least a portion of the powder. Backscattered radiation 420 is reflected from the surface of the powder and is obtained by the first device 430 and the second device 440 via the first port 431 and the second port 441. The first device includes a camera or a spectrometer. The second device includes a camera or a spectrometer. The camera may include a thermal camera, an optical camera, an IR camera, etc. The spectrometer may include a spectrum analyzer, a spectrometer that performs spectroscopy, etc. In this embodiment, the first device 430, the second device 440, the first port 431 and the second port 441 perform the function of a radiation collector (such as the radiation collector 321) and can be regarded as a radiation collector. In this embodiment, the deflector is separate from the radiation collector.

[0124] Filter 435 or 445 can be included in PBF system 400 to filter backscattered radiation 420 to obtain filtered backscattered radiation. The filter can include an optical filter, a lens, or a lens including a transparent material (such as a UV transparent material). The filter can be coupled to a port of a 3D printer. For example, the filter can include multiple filters 435, 445.

[0125] Focusing optics such as Figure 3 The focusing optics 380 may be included in a Figure 4 In various embodiments, the focusing optics 380 may include a lens or multiple lenses and / or mirrors to provide the backscattered radiation 420 to the first device 430 and the second device 440.

[0126] The first device 430 may be coupled to the first port 431 so that spectral information and / or optical information may be obtained from the first device in the form of a region of melted powder (305, see Figure 3 ) is obtained. A second device 440 may be coupled to the second port 441 so that spectral information and / or optical information may be obtained by the second device in the region of the melted powder (305, see Figure 3 ) is obtained from a second field of view of the 3-D printer. The first field of view and the second field of view may include spectral information and optical information. Both the first device and the second device can be coupled to a single port of the 3-D printer, or the first device can be coupled to a first port of the 3-D printer and the second device can be coupled to a second port of the 3-D printer. In an embodiment, the first device or the second device can be coupled to a port of the 3-D printer. However, more than two devices can be coupled to the ports of the 3-D printer, or each device can be coupled to each port of the 3-D printer. The 3-D printer may include more than two ports. The molten pool 620 includes melted powder within the region 305.

[0127] Including Figure 3 and Figure 4 In various embodiments, a shielding component 246 can be coupled to the radiator collector 221, 321 or the structure 328 and configured to prevent reflected power from the energy beam source 103, 211 (such as a laser) from damaging the spectrometer. The shielding component 246 can include an optical filter; a protective lens; a low-pass filter; a UV-transparent material (such as a film or a film on a lens); and / or a wall or barrier material that prevents radiation from penetrating therethrough. The shielding component 246 is configured to reduce or eliminate interference with the function of the spectrometer.

[0128] Figure 5 Details of apparatus 505 are shown. Apparatus 505 can be coupled to a 3-D printer and is a housing or optical instrument. Apparatus 505 includes a first device 530 coupled to port 531. Apparatus 505 can include a second device 540 coupled to a second port 541. Apparatus 505 can include a third device 550 coupled to a third port 551. Each device is coupled to a port so that spectral information and / or optical information can be obtained by each first device from a field of view of a region of melted powder (e.g., 305), wherein the region includes a melt pool 620 and a mushy region 610. Apparatus 505 can have more than three ports or fewer than three ports. Furthermore, apparatus 505 can have more than three devices or fewer than three devices. The first device includes a camera or a spectrometer. The second device includes a camera or a spectrometer. The camera can include a thermal camera, an optical camera, an IR camera, etc. The spectrometer can include a spectrum analyzer, a spectrometer that performs spectroscopy, etc.

[0129] Figure 6 A magnified view of a weld pool 605 in a powder bed 621 formed from deposited powder is shown, along with an energy beam 627 selectively applied to the surface of the powder to melt at least a portion of a region of the powder, forming a molten pool 620, and when the molten pool cools, forming a mushy region 610. Thus, the weld pool includes both the melted region of the powder and the mushy region.

[0130] Figure 7 Details of mushy region 710 are shown, including fragile region 730 and relaxed region 740. Mushy region 710 is the result of melting and solidifying over a certain temperature range across a region of material. Thus, mushy region 710 represents a coexistence of liquid and solid materials. The material being processed (3D printed) can include metal, metal powder, or other materials. Figure 7 The mushy zone is shown to include a larger percentage of solid material (i.e., solid fraction) at lower temperatures and a smaller percentage of solid material at higher temperatures. In other words, as the mushy zone cools, more solid material forms. Portions of the mushy zone with relatively less solid material (i.e., relatively more liquid) can continue to cool and solidify as the temperature decreases without problems. However, once the material reaches a certain percentage of solids, further cooling may lead to problems such as cracking, susceptibility to cracking, or large grain size. Therefore, the mushy zone can be divided into a relaxed zone 740 (which contains enough liquid to avoid cracking) and a fragile zone 730 (which contains enough solid to make it susceptible to cracking). In the example weld puddle 705, the solid fraction dividing the relaxed and fragile zones is 0.9. The vulnerability of the fragile zone 730 to solidification cracking may translate into a component 205 that includes cracking. In various embodiments, such cracking may be a defect. In this example, the boundary between the fragile zone 730 and the relaxed zone 740 is defined by the solid fraction, or 0.90. In other embodiments, the boundary may vary depending on factors such as the elemental composition of the material. In order to prevent cracking or hot tearing in the construction part, it may be desirable that the fragile area be as small as possible. In other words, it may be desirable to minimize the ratio of fragile area to relaxed area.

[0131] Thus, in various embodiments, a camera and / or spectrometer can obtain mushy zone information from the mushy zone, and process parameters can be modified based on the obtained mushy zone information to prevent cracking and / or large grain size in the component. The mushy zone information includes at least temperature information, temperature gradient, solidification rate, shape information, shape or ratio of the length of the relaxation zone to the length of the brittle zone. The shape or shape information of the mushy zone information includes depth, length, width, perimeter, area or volume. The relaxation zone 740 can include a solidification stress zone. For example, the solid fraction of the relaxation zone 740 can range from 0.4 to 0.9.

[0132] Figure 8Two different modes that can occur in a molten pool are shown. A conduction mode can occur when the melting of the powder by an energy beam (e.g., a laser beam) generates gases, and the gases cause the gas pressure to push down on the surface of the molten pool and create a shallow cavity in the molten pool. The conduction mode can be beneficial because a shallow cavity can lead to more efficient absorption of the laser beam energy because the laser photons can be reflected multiple times in the cavity (e.g., Figure 8 This gives the laser photons more opportunities to be absorbed.

[0133] In contrast, a keyhole pattern occurs when the powder is melted. A keyhole pattern (i.e., a keyhole) occurs when gas pressure is too high, resulting in the formation of deep cavities in the molten pool. The keyhole pattern can cause bubbles to form in the solidifying material as the molten pool moves during scanning, and the deep cavities collapse, trapping gas inside. In various embodiments, trapped bubbles can be a defect condition because they are perceived as defects in the material. In various embodiments, a keyhole pattern can be a defect condition because it is a condition that favors the creation of defects such as bubbles.

[0134] Active controlled monitoring to determine if the melt pool is in keyhole mode, and if so, modifying process parameters to place the melt pool in conduction mode, can improve the overall process energy (electrical power) efficiency of additive manufacturing and prevent or mitigate defect conditions. This can be performed by modifying the laser process (e.g., applying energy / laser beam to the surface of the powder and melting the powder) when the melt pool is determined to be in keyhole mode, preferably in the early stages of the keyhole. During the early stages of the keyhole, the effective absorptivity is significantly increased from the typical surface absorptivity of the powder material because a greater number of laser photons are allowed to be absorbed by the walls of the shallow keyhole well (e.g., Figure 8 In other words, the laser photons are lost and absorbed in the deep cavity. For example, the effective absorptivity of aluminum in keyhole mode can be increased from 0.15 to 0.70, an increase of 460%. The laser and process parameters can be actively controlled to stabilize and maintain this efficient melt pool state or condition. Figure 8As shown, from any of the disclosed PBF systems and apparatuses described above, powder 817 can be melted using an energy beam 827, and the melted powder forms a keyhole melt pool 820. During additive manufacturing of build 205, the melt pool is continuously monitored via a camera and / or spectrometer to indirectly determine the state of liquid melting and the transition of elements to vapor. It should be noted that at a pressure of 1 bar, the vaporization temperature of aluminum is approximately 2300°C. Keyhole melt pool 820 has a large, rounded top surface and a thin / narrow peak on the bottom surface. This keyhole melt pool 820 resembles a keyhole in a safety lock. Therefore, the term keyhole can be derived from this type of lock. Powder melting in keyhole mode can lead to defects in the build. However, the present disclosure prevents defects in the build by adjusting process parameters to maintain melt pool 821 within an acceptable temperature range and / or shape, preferably maintaining the melt pool in conductive mode. For example, forming melt pool 821 with a cavity 830 can prevent keyhole melt pool 820, thereby preventing defects in the build. Therefore, the determination of defect conditions can be based on an evaluation of the characteristics of the melt pool. The characteristics of the melt pool include at least keyhole information, size, shape, temperature, or temperature gradient. The shape includes the depth, length, width, perimeter, area, or volume of the melt pool. The keyhole information can include the shape of the melt pool, the cavity shape and / or size of the melt pool, the melt pool temperature and temperature gradient, and the flow rate (such as velocity) within the melt pool. In addition, to avoid keyholes and associated large-diameter spherical voids, a spectrometer can be used to detect spectral information (e.g., spectral intensity and the presence of photon emission associated with electronic transitions).

[0135] Figure 9 An example of obtaining spectral intensities from a spectrometer and processing spectral intensities obtained from a region of melted powder (including a melt pool and a mushy region) using computer 150 or processor 152 or a combination of computer and processor during additive manufacturing of build 109 is shown. Figure 9 The normal dashed line in the graph of shows what is considered a normal additive manufacturing operating condition during the additive manufacturing of build 109 (ie, an additive manufacturing condition with no defective conditions). Figure 9The contamination line in the graph of illustrates conditions considered to have defective conditions during additive manufacturing of build 109. For example, in this example, a defective condition is a spectral intensity of H (hydrogen spectral intensity) found to be greater than that found during normal additive manufacturing operation. However, a defective condition can be determined based on spectral intensities including water vapor spectral intensity or magnesium spectral intensity. The spectral intensity of hydrogen can be directly correlated to the presence of moisture and hydrocarbon contaminants. An increase in hydrogen can lead to an increase in porosity defects. This defective condition is determined based on an evaluation of the post-processing spectral intensity obtained compared to normal operating conditions for additively manufactured build 109. The presence and relative amount of metal or other elements can be detected by a spectral distribution (i.e., the spectral intensity distribution over an area of powder (such as melted powder in a melt pool or mushy region)) or by optical intensity / spectrum from a spectrometer or by optical information from an optical camera. The spectral information includes at least the spectral distribution or spectral intensity. The processor or computer is configured or further configured to determine at least the temperature distribution or state of the mushy region based on the spectral distribution or spectral intensity. The processed spectral information may be changes in the value of the spectral intensity during additive manufacturing of the build part.

[0136] Figure 10 An example of thermal radiation obtained by an optical camera, spectral intensity obtained by a spectrometer, and processing of the obtained thermal radiation and obtained spectral intensity by a computer or processor or a combination of a computer and a processor is shown. The obtained thermal radiation and obtained spectral intensity are obtained from the surface of a molten pool during additive manufacturing of a build 109. The approximate surface temperature of the molten pool can be determined by decomposing the obtained narrow elemental spectral emission / intensity (e.g., Figure 10 The presence and relative amounts of metals or other elements can be detected by the optical intensity / spectrum of the spectrometer.

[0137] Figure 11 An example of a computer 1150 is shown, which is coupled to a spectrometer 1160 using wires 1155 so that the computer 1150 processes spectral information obtained by the spectrometer from a region of melted powder (including the melt pool and the mushy region). However, the computer 1150 can be coupled to the spectrometer 1160 using wireless communication. The spectrometer 1160 is configured to obtain spectral information from a region of melted powder (including the melt pool and the mushy region) and then provide the obtained spectral information to the computer 1150 or a processor or a combination of the computer and the processor.

[0138] refer to Figure 12, a flowchart illustrates an example method 1200 of manufacturing. Method 1200 can be performed using any disclosed PBF system and apparatus, such as PBF system 100 and PBF apparatus 200. Method 1200 can include applying an energy beam to melt a region of material to form a molten pool, which cools to form a portion of a build part (1210). The energy beam can be a laser beam that melts a surface of powder in a region that may have been deposited from a depositor. The melted powder comprises a molten pool, and the molten pool comprises a mushy region.

[0139] Method 1200 may include obtaining spectral information from a region of the melted powder (1210). The spectral information includes spectral distribution, electromagnetic radiation, all electromagnetic waves of the electromagnetic spectrum, spectral intensity, thermal radiation from region 305, electron emission from region 305, radiation from electronic state transitions from region 305, and backscattered radiation 320 (see Figure 3 ), wherein backscattered radiation 320 includes a reflected energy beam (such as a reflected laser beam from region 305). In addition, obtaining spectral information includes controlling the spectrometer to perform spectral analysis at the second port with a second field of view of the region of the material, wherein the controller can perform the control function.

[0140] Method 1200 may include processing the spectral information to obtain processed spectral information (1230).A computer or a process or a combination of a computer and a process may obtain spectral information from a region of the powder.

[0141] Method 1200 may include obtaining an assessment based on the processed spectral information (1240). The assessment may use processor 152, computer 150, or a combination of processor and computer to compare the obtained and processed spectra and processed information to values, standards, criteria, data, such as historical data from previous additive manufacturing processes, and / or data from the aforementioned defect conditions. For example, the assessment may include: i) an assessment based on a difference between the spectral information and the standard being above or below a value or range of acceptable criteria; ii) an assessment based on a difference between the optical information and the standard being above or below a value or range of acceptable criteria; iii) an assessment based on a ratio of a characteristic value of the melt pool to a value of the standard; iv) an assessment based on a ratio of a characteristic value of the mushy region to a value of the standard; v) an assessment based on a change in spectral intensity values during additive manufacturing of the build part; vi) an assessment of a melt pool having an acceptable temperature range during additive manufacturing of the build part to prevent any defect conditions (i.e., any of the aforementioned defects), as well as any assessment disclosed in the PBF systems and apparatus disclosed above.

[0142] Method 1200 may include determining defect conditions for additive manufacturing based on the assessment (1250). Defect conditions for the additive manufacturing process (i.e., additively manufactured build) may include: i) defects in the build, such as porosity (keyholes, lack of fusion, etc.), larger pores, interlayer weld cracking, microstructural changes, increased residual stress, elemental composition changes, material property changes, or other defect types; ii) conditions that may subsequently lead to defects in the build (e.g., incorrect subsequent layers, where the width, height, or depth of the layer is too large or too small, the surface of the layer has large or small deviations (i.e., undulations); defects in the laser beam, process parameters (e.g., incorrect shape, distribution, or spot size, incorrect power of the energy applicator, etc.); iii) defects in the powder bed (e.g., too thick or too thin, grooves and / or ripples in one or more layers of the powder bed), as well as any of the assessments disclosed in the PBF systems and apparatus disclosed above. Additionally, defects may include increased build time and material costs due to suboptimal additive manufacturing conditions.

[0143] Method 1200 may also include obtaining optical information from the region of the melted powder. The optical information includes thermal radiation from region 305, electromagnetic radiation, all electromagnetic waves of the electromagnetic spectrum, including infrared (IR) light, near infrared (NIR) light, visible light, and ultraviolet (UV) light, and backscattered radiation 320 (see Figure 3 ), wherein backscattered radiation 320 includes a reflected energy beam (such as a reflected laser beam from region 305). Furthermore, obtaining optical information may include controlling a camera to perform optical imaging at a first port with a first field of view of a region of material (such as powder). The first field of view and the second field of view may be the same.

[0144] Method 1200 may also include processing the optical information to obtain processed optical information.A computer or a process or a combination of a computer and a process may obtain optical information from the region of the powder.

[0145] Method 1200 may further include performing an evaluation based on the processed optical information. For example, the evaluation may include: i) an evaluation based on whether the difference between the spectral information and the standard is above or below a value or range of acceptable criteria; ii) an evaluation based on whether the difference between the optical information and the standard is above or below a value or range of acceptable criteria; iii) an evaluation based on a ratio of a characteristic value of the melt pool to a value of the standard; iv) an evaluation based on a ratio of a characteristic value of the mushy region to a value of the standard; v) an evaluation based on a change in spectral intensity values during additive manufacturing of the build part; vi) an evaluation of a melt pool having an acceptable temperature range during additive manufacturing of the build part to prevent any defect conditions (i.e., any of the defects described above), as well as any evaluation disclosed in the PBF systems and apparatuses disclosed above.

[0146] Method 1200 may also include shielding the spectrometer from reflected power from the laser that may generate the laser beam. The shielding may include a shielding component 246 that may be coupled to the radiator collector 221, 321 or the structure 328 and configured to prevent reflected power from the energy beam source 103, 211 (such as a laser) from damaging the spectrometer. The shielding component 246 may include an optical filter; a protective lens; a low-pass filter; a UV transparent material (such as a film or a film on a lens); and / or a wall or barrier material that prevents radiation from penetrating therethrough. The shielding component 246 is configured to reduce or eliminate interference with the function of the spectrometer.

[0147] Because the molten pool includes a mushy region, method 1200 may also include obtaining mushy region information from the region. The mushy region information includes temperature information, temperature gradient, solidification rate, or shape information. Figure 7 The mushy area 710 is the result of melting and solidification of the material within a certain temperature range. Therefore, the mushy area 710 is the coexistence of liquid and solid materials. The material can include metal, metal powder or other materials. Figure 7 As shown, the mushy zone includes a larger percentage of solid fractions at lower temperatures and a smaller percentage of solid fractions at higher temperatures. Due to this physical phenomenon, mushy zone 710 includes a fragile zone 730 and a relaxed zone 740. Weak zone 730 is a region susceptible to solidification cracking, which can translate into a build 205 containing cracks. For example, fragile zone 730 may include a solid fraction between 0.90 and 0.99. To prevent cracking or hot tearing in the build, liquid is required in fragile zone 730 during solidification. Furthermore, large grain sizes within the build are to be prevented. Therefore, a camera and / or spectrometer obtains mushy zone information from the mushy zone, and process parameters can be modified based on the obtained mushy zone information to prevent cracking and / or large grain sizes in the build. Mushy zone information includes at least temperature information, temperature gradient, solidification rate, shape information, or the ratio of the length of the relaxed zone to the length of the mushy zone. The shape or shape information of the mushy zone information includes depth, length, width, perimeter, area, or volume. The relaxation region 740 may include a solidification stress region. For example, the relaxation region 740 may range from a solid fraction between 0.4 and 0.9.

[0148] Method 1200 may also include processing the mushy region information.A computer or a process or a combination of a computer and a process may obtain the mushy region information from the mushy region.

[0149] The method 1200 may further include wherein the evaluation is further performed based on the mushy region information. The evaluation may be a variation of any disclosed method as described above and based on the mushy region information disclosed above.

[0150] Method 1200 may also include evaluating characteristics of the melt pool. Characteristics of the melt pool may include keyhole information, size, shape, temperature, or temperature gradient. Shape and shape information may include depth, length, width, perimeter, area, or volume. Keyhole information may include the shape of the melt pool, the shape and / or size of the melt pool cavity, the temperature and temperature gradient of the melt pool, and flow rate (such as velocity) within the melt pool.

[0151] Method 1200 may also include modifying process parameters for additive manufacturing based on the defect condition. The process parameters include at least laser power, hatch spacing, scan speed, beam profile of the laser beam, beam size of the laser beam, or beam shape of the laser beam. Modification of the process parameters may include, for example, decreasing or increasing hatch spacing, scan speed, beam profile of the laser beam, beam size of the laser beam, or beam shape or intensity of the energy beam (such as laser beam intensity), adjusting the process parameters to maintain the temperature of the molten pool within an acceptable range during additive manufacturing of the build part, or adjusting the laser power and at least the hatch spacing, scan speed, beam profile, or beam shape.

[0152] Method 1200 may also include determining at least the temperature distribution or physical state of the melt pool or mushy region based on the spectral distribution or spectral intensity. A camera may obtain thermal radiation from the melt pool, and a spectrometer may obtain spectral information from the melt pool. A computer or processor, or a combination of a computer and a processor, processes the obtained thermal radiation and the obtained spectral intensity. The obtained thermal radiation and the obtained spectral intensity are obtained from the surface of the melt pool during additive manufacturing of the component 109. The approximate surface temperature of the melt pool can be determined by decomposing the obtained spectral intensity and superimposing the obtained spectral intensity on the obtained and processed broad temperature emission (i.e., thermal radiation) from the melt pool surface. The presence and relative amount of metals or other elements can be detected by the optical intensity / spectrum of the spectrometer. The processed spectral information may include changes in spectral intensity values during additive manufacturing of the component, or may include hydrogen spectral intensity, water vapor spectral intensity, or magnesium spectral intensity. These spectral intensities can be directly correlated to the presence of moisture and hydrocarbon contaminants. For example, a defect condition is the detection of a spectral intensity of H (hydrogen spectral intensity) that is greater than that observed during normal additive manufacturing operation. The increase in hydrogen will result in an increase in porosity defects. This defect condition is determined based on an evaluation of the intensity of the spectrum obtained after processing compared to normal operating conditions of the additively manufactured component 109. The presence and relative amount of metal or other elements can be detected by a spectral distribution (i.e., a spectral intensity distribution over an area of powder (such as a melt pool or melted powder in a mushy zone)) or optical intensity / spectrum of a spectrometer or by optical information from an optical camera. The processor or computer is configured or further configured to determine a temperature distribution or state of at least the mushy zone based on the spectral distribution or spectral intensity.

[0153] refer to Figure 13 , a flowchart shows an example method 1300 of manufacturing. The method 1300 can be performed with any disclosed PBF system and apparatus (such as the PBF system 100 and the PBF apparatus 200). The method 1300 can include applying an energy beam to melt the material to form a molten pool, which cools to form a portion of the build part (1310). This feature is similar to the above Figure 12 The same as feature 1210 in.

[0154] Method 1300 may include obtaining spectral information from the melt pool (1320), similar to the above-described Figure 12 , and because the melt pool is within this region, all of the features described above related to this region can be applied to the melt pool.

[0155] Method 1300 may include adjusting process parameters based on spectral information to shape the weld pool to obtain a desired effective absorptivity of a portion of the weld pool, for example to increase the effective absorptivity relative to the absorptivity of the surface of the powder or material deposited by the depositor (1330). Active controlled monitoring can improve the overall process energy (power) efficiency of additive manufacturing. This can be performed by operating the laser process (e.g., applying energy / laser beam to the surface of the powder and melting the powder) in the early stages of the keyhole. During the early stages of the keyhole, the effective absorptivity is significantly increased from the typical surface absorptivity of the powder material. A greater number of laser photons are allowed to be absorbed in the walls of the shallow keyhole well. The effective absorptivity of aluminum in keyhole mode can be increased from 0.15 to 0.70, an increase of 460%. The laser and process parameters can be actively controlled to stabilize and maintain this efficient molten pool state or condition. As Figure 8As shown, from any of the disclosed PBF systems and apparatuses described above, powder 817 can be melted using an energy beam 827, and the melted powder forms a keyhole melt pool 820. During additive manufacturing of build 205, the melt pool is continuously monitored via a camera and / or spectrometer to indirectly determine the state of liquid melting and the transition of elements to vapor. It should be noted that the vaporization temperature of aluminum is approximately 2300°C at a pressure of 1 bar. Keyhole melt pool 820 has a large, rounded top surface and a thin / narrow peak on the bottom surface. This keyhole melt pool 820 resembles a keyhole in a safety lock. Therefore, the term keyhole can be derived from this type of lock. Powder melting in a keyhole mode can lead to defects in the build. However, the present invention prevents defects in the build by adjusting process parameters to maintain melt pool 821 within an acceptable temperature range and / or shape. For example, forming melt pool 821 with a cavity 830 can prevent keyhole melt pool 820, thereby preventing defects in the build. Therefore, the determination of defect conditions can be based on an assessment of the characteristics of the melt pool. The characteristics of the melt pool include at least keyhole information, size, shape, temperature, or temperature gradient. The shape includes the depth, length, width, perimeter, area, or volume of the melt pool. The keyhole information can include the shape of the melt pool, the cavity shape and / or size of the melt pool, the temperature and temperature gradient of the melt pool, and the flow rate (such as velocity) within the melt pool. In addition, to avoid keyholes and associated large-diameter spherical voids, a spectrometer can be used to detect spectral information (such as spectral intensity and the presence of photon emission associated with electronic transitions).

[0156] Method 1300 may include depositing a material, such as a powder, on the build plate by a depositor such that a powder bed is formed on the build plate, and a build is formed within the powder bed by energy beam melting power.

[0157] refer to Figure 14 , a flowchart illustrates an example method 1400 of manufacturing. The method 1400 can be performed using any of the disclosed PBF systems and apparatuses, such as the PBF system 100 and the PBF apparatus 200. The method 1400 can include applying an energy beam to melt a material to form a molten pool that cools to form a portion of a build part, wherein the molten pool includes a mushy region (1410). This feature is similar to Figure 12 and 13 Because the molten pool includes the mushy zone, and because the molten pool is within this zone, all of the features described above with respect to this zone can be applied to the mushy zone.

[0158] Method 1400 may include obtaining mushy zone information for the mushy zone (1420) and may include processing the mushy zone information (1430). A camera and / or a spectrometer may obtain the mushy zone information from the mushy zone, and process parameters may be modified based on the obtained mushy zone information to prevent cracking and / or large grain size in the build part. The mushy zone information includes at least temperature information, a temperature gradient, a solidification rate, shape information, a shape, or a ratio of a length of a relaxed zone to a length of a fragile zone. The shape or shape information of the mushy zone information includes depth, length, width, perimeter, area, or volume. A computer or a process or a combination of a computer and a process may obtain the mushy zone information from the mushy zone.

[0159] refer to Figure 15 , a flowchart illustrates an example method of manufacturing 1400. Method 1500 can be performed using any disclosed PBF system and apparatus, such as PBF system 100 and PBF apparatus 200. Method 1500 may include applying an energy beam to melt a material to form a molten pool, which cools to form a portion of a build part, wherein the molten pool includes a mushy region (1510); obtaining mushy region information of the mushy region (1520); and processing the mushy region information to obtain processed mushy region information (1530). These features are similar to those of 1410, 1420, and 1420 described above.

[0160] Method 1500 may include obtaining an assessment based on the processed mushy zone information (1540). A camera and / or a spectrometer may obtain the mushy zone information from the mushy zone, and process parameters may be modified based on the obtained mushy zone information to prevent cracking and / or large grain size in the component. The mushy zone information includes at least temperature information, a temperature gradient, a solidification rate, shape information, a shape, or a ratio of the length of the relaxed zone to the length of the brittle zone. The shape of the mushy zone information or shape information includes depth, length, width, perimeter, area, or volume. A computer or process or a combination of a computer and a process may obtain the mushy zone information from the mushy zone.

[0161] The evaluation can use processor 152, computer 150, or a combination of processor and computer to compare the acquired and processed spectra and processed information to values, standards, criteria, and data such as historical data from previous additive manufacturing processes and / or data from the defect conditions described above. For example, the evaluation can include: i) an evaluation based on the difference between the spectral information and the standard being above or below a value or range of acceptable criteria; ii) an evaluation based on the difference between the optical information and the standard being above or below a value or range of acceptable criteria; iii) an evaluation based on a ratio of a characteristic value of the melt pool to a value of the standard; iv) an evaluation based on a ratio of a characteristic value of the mushy region to a value of the standard; v) an evaluation based on changes in spectral intensity values during additive manufacturing of the build part; and vi) an evaluation of a melt pool having an acceptable temperature range during additive manufacturing of the build part to prevent any defect conditions (i.e., any of the defects described above).

[0162] Method 1500 may include determining defect conditions for additive manufacturing based on the assessment (1550). Defect conditions for the additive manufacturing process (i.e., additively manufactured build) may include: i) defects in the build, such as porosity (keyholes, lack of fusion, etc.), larger pores, interlayer weld cracking, microstructural variations, increased residual stress, elemental composition variations, material property variations, or other defect types; ii) conditions that may subsequently lead to defects in the build (e.g., incorrect subsequent layers, where the width, height, or depth of a layer is too large or too small, the surface of a layer has large or small deviations (i.e., undulations); defects in the laser beam, process parameters (e.g., incorrect shape, distribution, or spot size, incorrect power of the energy applicator, etc.); iii) defects in the powder bed (e.g., too thick or too thin, grooves and / or ripples in one or more layers of the powder bed), as well as any of the assessments disclosed in the PBF systems and apparatus disclosed above. Additionally, defects may include increased build time and material costs due to suboptimal additive manufacturing conditions.

[0163] It should be noted that the above operations are provided as examples only. Although some specific examples are given, those skilled in the art will appreciate that, upon understanding the disclosure provided herein, additional possibilities for automatic, semi-automatic, or manual control of the systems and devices of the disclosed support system formation and removal methods and apparatus described herein will fall within the scope of the present disclosure.

[0164] In addition, aspects of the present disclosure can be implemented using hardware, software, or a combination thereof, and can be implemented in one or more computers or computer systems, processors, or other processing systems. In aspects of the present disclosure, features are directed to one or more computers, processors, or computer systems capable of performing the functions described herein.

[0165] Computer programs (also referred to as computer control logic) may be stored in memory 154 and / or secondary storage. Such computer programs, when executed, enable the PBF system to perform features according to aspects of the present disclosure, as described herein. In particular, the computer programs, when executed, enable processor 152 to perform features according to aspects of the present disclosure.

[0166] In aspects of the present disclosure, where the method is implemented using software, the software can be stored in a computer program product and loaded into computer 150 using a removable storage drive, a hard drive, or one or more interfaces. When executed by a processor, the control logic (software) causes the processor to perform the functions described herein. In some examples, computer 150 may include one or more PBF controllers, for example, to control any one or a combination of the PBF systems described above. In another aspect of the present disclosure, the system is primarily implemented in hardware using hardware components such as application-specific integrated circuits (ASICs). Implementing a hardware state machine to perform the functions described herein will be readily apparent to one skilled in one or more relevant arts.

[0167] In this specification, reference to an aspect, aspect, or example or examples means that a particular feature, structure, or characteristic described in conjunction with the embodiment or example may be a feature included in at least one example of the present invention. Thus, the appearance of a phrase in this specification in an aspect, aspect, example, or examples, or multiple places, does not necessarily refer to the same example. Furthermore, in one or more embodiments or examples, the particular features, structures, or characteristics may be combined in any suitable combinations and / or subcombinations.

[0168] Throughout this disclosure, the term substantially or approximately may be used as a modifier to describe the geometric relationship between elements or the shape of an element or component. While the term substantially or approximately is not limited to specific variations and may encompass any variation that one of ordinary skill in the art understands to be an acceptable level of variation, some examples are provided below. In one example, the term substantially or approximately may include variations of less than 10% of the size of an object or component. In another example, the term substantially or approximately may include variations of less than 5% of the size of an object or component. If the term substantially or approximately is used to define the angular relationship of one element to another, a non-limiting example of the term substantially or approximately may include variations of 5 degrees or less. These examples are not intended to be limiting and may be added or subtracted based on an understanding of the limits that are acceptable to one of ordinary skill in the relevant art.

[0169] For the purposes of this disclosure, when the aspects or articles described herein are in an orientation for use, directional terms are generally expressed relative to a standard reference system. In some examples, directional terms are generally expressed relative to a left-hand coordinate system.

[0170] Terms such as a, an, and the refer not only to a single entity but also to a general category that can be illustrated using a specific example. The terms one, an, and the can be used interchangeably with the term at least one. The phrases at least one of the following list and at least one of the following list refer to any one of the items in the list and any combination of two or more items in the list. Unless otherwise specified, all numerical ranges are inclusive of their endpoints and non-integer values between the endpoints.

[0171] The terms first, second, third, and fourth, as well as other numerical values, may be used in this disclosure. It should be understood that unless otherwise indicated, these terms are used only in their relative sense. In particular, certain components may exist in interchangeable and / or identical multiples (e.g., in pairs). For these components, in the description, the designations first, second, third, and / or fourth may be applied to these components for convenience only.

[0172] The term powder bed fusion (PBF) is used throughout this disclosure. PBF systems can include a wide variety of additive manufacturing (AM) technologies, systems, and methods. Thus, a PBF system or process referenced in this disclosure may include, among other things, the following printing technologies: direct metal laser sintering (DMLS), electron beam melting (EBM), selective heat sintering (SHS), selective laser melting (SLM), and selective laser sintering (SLS). Other PBF processes relevant to the principles of the present disclosure also include processes currently under consideration or in commercial development. Aspects of the present disclosure may also be related to non-metallic additive manufacturing and / or metal / binder additive manufacturing (e.g., binder jetting), which may forgo an energy beam source and instead apply a binder or other bonding agent to form each layer. In the case of binder jetting, the solidified or green body can be sintered or fused in a furnace and / or infiltrated with bronze or other alloys.

[0173] The detailed description described above in conjunction with the accompanying drawings is intended to provide a description of various example embodiments of the concepts disclosed herein and is not intended to represent the only embodiment in which the present disclosure may be practiced. The terms "exemplary" and "example" as used in this disclosure mean "serving as an example, instance, or illustration" and are not necessarily to be construed as preferred or superior to other embodiments presented in this 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 cases, well-known structures and components may be shown in block diagram form, or omitted entirely, to avoid obscuring the various concepts presented in this disclosure.

[0174] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. It will be apparent to those skilled in the art that various modifications to the exemplary embodiments presented throughout this disclosure will be apparent. Therefore, the claims are not intended to be limited to the example embodiments presented throughout this disclosure, but are to be given the full scope consistent with the language claims. Structural and functional equivalents of the elements of the exemplary embodiments described throughout this disclosure that are known or will later be known to those of ordinary skill in the art are intended to be covered by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims. Unless an element is explicitly stated using the phrase "means for..." or, in the case of a method claim, an element is explicitly stated using the phrase "step for...", otherwise, the claim element is not interpreted under 35 U.S.C. § 112(f) or similar provisions in the applicable jurisdiction.

Claims

1. A method for additive manufacturing, comprising: applying an energy beam to melt a region of material to form a weld puddle that cools to form a portion of a build part; obtaining spectral information from the region; processing the spectral information to obtain processed spectral information; Obtaining an assessment based on the processed spectral information; as well as Defective conditions of the additive manufacturing are determined based on the evaluation.

2. The method according to claim 1, further comprising: The material is deposited onto a build plate, wherein the material comprises a powder.

3. The method according to claim 1, further comprising: obtaining optical information from the region; as well as processing the optical information to obtain processed optical information, Therein, the evaluation is also based on processed optical information.

4. The method according to claim 3, wherein: Obtaining the optical information includes: controlling a camera to perform optical imaging at a first port with a first field of view of an area of the material, and Obtaining the spectral information includes controlling a spectrometer to perform spectroscopy at a second port with a second field of view of the region of the material. The method of claim 4 , wherein the first field of view and the second field of view are the same.

6. The method according to claim 3, wherein: Obtaining the spectral information includes receiving backscattered radiation from the region.

7. The method according to claim 6, wherein: Obtaining the spectral information further includes filtering the backscattered radiation to obtain filtered backscattered radiation.

8. The method of claim 4, wherein the energy beam comprises a laser beam, and the method further comprises: The spectrometer is shielded from the reflected power of the laser light.

9. The method of claim 6, wherein the weld pool includes a mushy zone, and further comprising: obtaining mushy area information from the region; as well as processing the mushy area information, Wherein, the evaluation is further based on the mushy area information.

10. The method of claim 9, wherein the mushy zone information includes at least temperature information, temperature gradient, solidification rate, or shape information.

11. The method of claim 9, wherein the mushy region comprises a relaxed region and a fragile region, and in, The mushy area information includes a ratio of a length of the relaxed area to a length of the fragile area.

12. The method of claim 3, wherein the evaluating includes characteristics of the weld puddle.

13. The method of claim 12, wherein the characteristics of the weld puddle include keyhole information.

14. The method of claim 12, wherein the characteristic of the weld pool includes at least size, shape, temperature, or temperature gradient.

15. The method of claim 14, wherein the shape comprises depth, length, width, perimeter, area, or volume.

16. The method according to claim 3, further comprising: Process parameters of the additive manufacturing are modified based on the defect condition.

17. The method of claim 16, wherein the modifying comprises: The process parameters are adjusted to maintain an acceptable temperature of the weld puddle during additive manufacturing of the build part. The method of claim 16 , wherein the energy beam comprises a laser beam.

19. The method of claim 18, wherein the process parameters include at least laser power, hatch spacing, scanning speed, beam profile of the laser beam, beam size of the laser beam, or beam shape of the laser beam.

20. The method of claim 19, wherein the modifying comprises: The laser power is adjusted, and at least the hatch spacing, the scanning speed, the beam distribution or the beam shape is adjusted. The method according to claim 1 , wherein the spectral information comprises at least spectral distribution or spectral intensity.

22. The method of claim 21 , wherein the weld pool comprises a molten pool and a mushy zone, and the method further comprises: The temperature distribution or the physical state of at least the molten pool or the mushy zone is determined based on the spectral distribution or the spectral intensity.

23. The method according to claim 21, wherein The processed spectral information is the change in the value of the spectral intensity during the additive manufacturing of the building part.

24. The method of claim 23, wherein the spectrum intensity comprises hydrogen spectrum intensity, water vapor spectrum intensity, or magnesium spectrum intensity.

25. The method according to claim 1, wherein Obtaining the spectral information includes performing spectroscopy on backscattered radiation from the region.

26. A method for additive manufacturing, comprising: applying an energy beam to melt the material to form a weld puddle that cools to form a portion of the build part; obtaining spectral information from the weld pool; as well as Process parameters are adjusted based on the spectral information to shape the weld puddle to achieve a desired effective absorptivity of a portion of the weld puddle.

27. The method according to claim 26, further comprising: The material is deposited onto a build plate, wherein the material comprises a powder.

28. The method of claim 26, wherein the energy beam comprises a laser, and in, The spectral information includes at least the intensity, depth, length, width, circumference, area or volume of the reflected laser light.

29. A method for additive manufacturing, comprising: applying an energy beam to melt a material to form a weld puddle that cools to form a portion of a build, wherein the weld puddle includes a mushy region; Obtaining mushy area information of the mushy area; and Process parameters are modified based on the mushy zone information.

30. A method for additive manufacturing, comprising: applying an energy beam to melt a material to form a weld puddle that cools to form a portion of a build, wherein the weld puddle includes a mushy region; obtaining mushy area information of the mushy area; processing the mushy area information to obtain processed mushy area information; obtaining an assessment based on the processed mushy area information; as well as Defective conditions of the additive manufacturing are determined based on the evaluation.

31. A three-dimensional (3-D) printer for additive manufacturing, comprising: a depositor configured to deposit a material; an energy beam source configured to generate an energy beam, wherein the energy beam is configured to melt a region of the material to form a weld puddle that cools to form a portion of a build part; a first device configured to obtain spectral information from the region; and a processor or computer in communication with the first device and configured to: processing the spectral information to obtain processed spectral information, performing an evaluation based on the processed spectral information, and Defective conditions of the additive manufacturing are determined based on the evaluation.

32. The printer according to claim 31, wherein The depositor is configured to deposit the material onto a build plate, wherein the material comprises a powder, and the printer further comprises: A deflector is configured to apply the energy beam to the area of the material.

33. The printer of claim 31 , further comprising: a second device configured to obtain optical information from the area, wherein the processor or the computer is further configured to process the optical information to obtain processed optical information, and Therein, the evaluation is also based on processed optical information.

34. The printer of claim 33, wherein the spectral information comprises backscattered radiation received from the region.

35. The printer of claim 34, further comprising: A filter is configured to filter the backscattered radiation to obtain filtered backscattered radiation.

36. The printer of claim 33, wherein the first device comprises a spectrometer and the second device comprises a camera.

37. The printer of claim 36, wherein the camera is coupled to a first port of the printer and the spectrometer is coupled to a second port of the printer.

38. The printer of claim 36, wherein the spectrometer and the camera are coupled to a structure.

39. The printer of claim 38, wherein the energy beam source comprises a laser, and the printer further comprises: A shield is coupled to the structure and configured relative to the spectrometer and the laser to prevent reflected power from the laser from damaging the spectrometer.

40. The printer of claim 36, wherein the camera is coupled to a first port of a device and the spectrometer is coupled to a second port of the device.

41. The printer of claim 40, wherein the device is coupled to the printer, and in, The device is a housing or an optical instrument.

42. The printer of claim 33, wherein the weld pool includes a mushy region, and in, The optical information includes mushy area information of the mushy area.

43. The printer of claim 42, wherein the mushy area information includes at least temperature information, temperature gradient, solidification rate, or shape information.

44. The printer of claim 42, wherein the mushy region comprises a relaxed region and a fragile region, and in, The mushy area information includes a ratio of a length of the relaxed area to a length of the fragile area.

45. The printer of claim 31 , wherein the evaluation includes characteristics of the weld puddle.

46. The printer of claim 45, wherein the characteristics of the weld puddle include keyhole information.

47. The printer of claim 45, wherein the characteristic comprises at least size, shape, temperature, or temperature gradient.

48. The printer of claim 47, wherein the shape comprises depth, length, width, perimeter, area, or volume.

49. The printer of claim 31 , further comprising: A controller is configured to modify a process parameter based on the evaluation.

50. The printer of claim 49, wherein the controller is further configured to modify the process parameters so that an acceptable temperature of the weld puddle is maintained during additive manufacturing of the build part.

51. The printer of claim 49, wherein the energy beam source comprises a laser, and wherein the energy beam is a laser beam.

52. The printer of claim 51 , wherein the process parameters include at least laser power, hatch spacing, scanning speed, beam profile of the laser beam, beam size of the laser beam, beam shape of the laser, or any combination thereof.

53. The printer according to claim 31, wherein the spectral information includes at least spectral distribution or spectral intensity.

54. The printer of claim 53, wherein the weld pool comprises a mushy region, and in, The processor or the computer is further configured to determine at least a temperature distribution or state of the mushy zone based on the spectral distribution or the spectral intensity.

55. The printer according to claim 53, wherein The processed spectral information is the change in the value of the spectral intensity during the additive manufacturing of the building part.

56. The printer of claim 55, wherein the spectral intensity comprises hydrogen spectral intensity, water vapor spectral intensity, or magnesium spectral intensity.

57. A three-dimensional (3-D) printer for additive manufacturing, comprising: a depositor configured to deposit a material; an energy beam source configured to generate an energy beam, wherein the energy beam is configured to melt a region of the material to form a weld puddle that cools to form a portion of a build part; a first device configured to obtain spectral information from the region; as well as A controller is configured to adjust process parameters to shape the weld puddle based on the spectral information to obtain a desired effective absorptivity of a portion of the weld puddle.

58. The printer of claim 57, wherein the energy beam comprises a laser, and in, The spectral information includes at least the intensity, depth, length, width, circumference, area or volume of the reflected laser light.

59. The printer of claim 58, wherein the depth, length, width, circumference, area or volume is of the weld puddle.

60. A three-dimensional (3-D) printer for additive manufacturing, comprising: a depositor configured to deposit a material; an energy beam source configured to generate an energy beam, wherein the energy beam is configured to melt a region of the material to form a weld puddle that cools to form a portion of a build part; a first device configured to obtain information of the weld pool; as well as A controller is configured to modify process parameters based on the information to maintain an acceptable temperature of the weld puddle during additive manufacturing of a build part.

61. A three-dimensional (3-D) printer for additive manufacturing, comprising: a depositor configured to deposit a material; an energy beam source configured to generate an energy beam, wherein the energy beam is configured to melt a region of the material to form a weld puddle, the weld puddle cools to form a portion of a build, wherein the weld puddle includes a mushy region; a first device configured to obtain mushy area information from the mushy area; as well as A controller is configured to modify a process parameter based on the mushy zone information.

62. A three-dimensional (3-D) printer for additive manufacturing, comprising: a depositor configured to deposit a material; an energy beam source configured to generate an energy beam, wherein the energy beam is configured to melt a region of the material to form a weld puddle, the weld puddle cools to form a portion of a build, wherein the weld puddle includes a mushy region; a first device configured to obtain mushy area information from the mushy area; and a processor or computer in communication with the first device and configured to: processing the mushy area information to obtain processed mushy area information, performing an evaluation based on the processed mushy area information, and Defective conditions of the additive manufacturing are determined based on the evaluation.

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