The present disclosure relates generally to Additive Manufacturing systems, and more particularly, to material handling in Additive Manufacturing systems.
Additive Manufacturing (“AM”) systems, also described as three-dimensional (“3-D”) printer systems, can produce structures (referred to as build pieces) with geometrically complex shapes, including some shapes that are difficult or impossible to create with conventional manufacturing processes. AM systems, such as powder-bed fusion (“PBF”) systems, create build pieces layer-by-layer. Each layer or ‘slice’ is formed by depositing a layer of powder and exposing portions of the powder to an energy beam. The energy beam is applied to melt areas of the powder layer that coincide with the cross-section of the build piece in the layer. The melted powder cools and fuses to form a slice of the build piece. The process can be repeated to form the next slice of the build piece, and so on. Each layer is deposited on top of the previous layer. The resulting structure is a build piece assembled slice-by-slice from the ground up.
In some cases, substances found in the atmosphere can change one or more material properties of powder used in PBF systems. For example, some metal powders used in PBF systems can react with water, oxygen, and other substances in the atmosphere. Exposure to water in the atmosphere (e.g., humidity) and oxygen can change a material property of some powders by oxidizing the powder material, e.g., oxidizing an iron powder by turning the iron into iron oxide. In this case, the material property that is changed is a chemical property of the powder material. In another example, humidity can physically change some powders, e.g., by causing the powder to moisten and clump together, thus reducing the ability of the powder to flow through pipes, openings, etc. In this case, the material property that is changed is a physical property of the bulk powder, e.g., the flowability of the bulk powder, which may be the result of changes to multiple material properties that affect the flowability.
Several aspects of apparatuses and methods for material handling in AM systems will be described more fully hereinafter.
In various aspects, an apparatus for transporting metal powder can include a chamber, a transporter that transports the metal powder through the chamber, and an environmental system that creates an environment in the chamber that decreases exposure of the metal powder to a substance that changes a material property of the metal powder.
In various aspects, an apparatus for a powder-bed fusion system can include a chamber, a transporter that transports the metal powder through the chamber, and a vacuum pump connected to the chamber.
In various aspects, an apparatus for a powder-bed fusion system can include a chamber, a transporter that transports the metal powder through the chamber, an inert gas system that injects an inert gas into the chamber.
In various aspects, an apparatus for transporting metal powder can include a chamber, a transporter that transports the metal powder through the chamber, and an environmental system that creates an environment in a chamber that decreases exposure of the metal powder to a substance that causes a property of a build piece formed from fusing the metal powder to be different than the property of a build piece formed from fusing metal powder not exposed to the substance.
In various aspects, an apparatus for a powder-bed fusion system can include a first chamber that accepts a first metal powder and a second metal powder, a second chamber connected to the first chamber, and a dose controller that controls a dose of the second metal powder from the second chamber into the first chamber based on a characteristic of at least the first metal powder or the second metal powder.
In various aspects, an apparatus for a powder-bed fusion system can include a chamber that accepts a metal powder from the powder-bed fusion system, the chamber including a first port and a second port, a powder characterizer that determines a characteristic of the metal powder, a controller that determines whether to reuse the metal powder based on the characteristic, and a powder transporter that transports the metal powder through the first port if the controller determines the metal powder should be reused and that transports the metal powder through the second port if the controller determines the metal powder should not be reused.
In various aspects, an apparatus for a powder-bed fusion system can include a chamber that accepts a metal powder from the powder-bed fusion system, a decontamination system that decontaminates the metal powder, and a powder transporter that transports the metal powder into the chamber and that transports the decontaminated metal powder out of the chamber.
In various aspects, an apparatus for a powder-bed fusion system can include a powder-bed fusion apparatus that creates three-dimensional printed structures by fusing metal powder, and a metal atomizer connected to the PBF apparatus. The metal atomizer can create the metal powder from one or more metal sources including recycled three-dimensional printed structures. The metal atomizer can include, for example, a metal atomizer that heats and melts the metal from the metal sources and an atomization system that atomizes the liquid metal to form metal powder.
In various aspects, a method for transporting metal powder in a chamber can include creating an environment in the chamber that decreases exposure of the metal powder to a substance that changes a material property of the metal powder, and transporting the metal powder through the chamber.
In various aspects, a method for transporting metal powder in a chamber can include creating a vacuum in the chamber, and transporting the metal powder through the vacuum in the chamber.
In various aspects, a method for transporting metal powder in a chamber can include injecting an inert gas into the chamber, and transporting the metal powder through the inert gas in the chamber.
In various aspects, a method for transporting metal powder can include creating an environment in a chamber that decreases exposure of the metal powder to a substance that causes a property of a build piece formed from fusing the metal powder to be different than the property of a build piece formed from fusing metal powder not exposed to the substance, and transporting the metal powder through the chamber.
In various aspects, a method for a powder-bed fusion system can include accepting a first metal powder into a first chamber, and dosing a second metal powder into the first chamber from a second chamber connected to the first chamber based on a characteristic of at least the first metal powder or the second metal powder.
In various aspects, a method for a powder-bed fusion system can include accepting a metal powder from the powder-bed fusion system into a chamber, the chamber including a first port and a second port, determining a characteristic of the metal powder, determining whether to reuse the metal powder based on the characteristic, and transporting the metal powder through the first port in response to the determination to reuse the metal powder and transporting the metal powder through the second port in response to the determination not to reuse the metal powder.
In various aspects, a method for a powder-bed fusion system can include accepting a metal powder from the powder-bed fusion system into a chamber, decontaminating the metal powder in the chamber, and transporting the decontaminated metal powder out of the chamber.
In various aspects, a method for powder-bed fusion can include creating three-dimensional printed structures by fusing metal powder, and creating the metal powder from one or more metal sources including recycled three-dimensional printed structures.
Other aspects will become readily apparent to those skilled in the art from the following detailed description, wherein is shown and described only several embodiments by way of illustration. As will be realized by those skilled in the art, concepts herein are capable of other and different embodiments, and several details are capable of modification 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 as restrictive.
Various aspects of will now be presented in the detailed description by way of example, and not by way of limitation, in the accompanying drawings, wherein:
The detailed description set forth below in connection with the appended drawings is intended to provide a description of various exemplary embodiments of the concepts disclosed herein and is not intended to represent the only embodiments in which the disclosure may be practiced. The term “exemplary” used in this disclosure means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over 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 disclosure may be practiced without these specific details. In some instances, well-known structures and components may be shown in block diagram form, or omitted entirely, in order to avoid obscuring the various concepts presented throughout this disclosure.
This disclosure is directed to material handling in AM systems, such as powder-bed fusion (PBF) systems. In particular, various exemplary embodiments are presented to illustrate aspects of decreasing exposure of a powder to substances that change a material property of the powder and/or that causes a property of a build piece formed from fusing the powder to be different than the property of a build piece formed from fusing powder not exposed to the substance. In some cases, the property of the build piece can be a material property. The term “substance” should be understood to refer to a physical substance. In this regard, electromagnetic waves (e.g., visible light), acoustic waves (e.g., sound waves), and thermal energy (e.g., thermal radiation, thermal conduction), etc., are not substances as that term is used herein.
Exposure of powder to some substances can reduce the powder's effectiveness for use in a PBF system. For example, oxygen in the atmosphere can oxidize some powder materials, which can add alloying agents that can reduce material performance parameters of build pieces. Furthermore, oxidation of the powder material can result in build pieces with coarser microstructure, which can reduce the quality of build piece. In another example, exposure of the powder to atmospheric water, i.e., humidity, can reduce the powder's effectiveness in a PBF system. Humidity can cause powder to clump together due to moisture condensing in between the grains of powder. Clumped powder can more easily clog various parts of the PBF system, such as augers and pipes.
Various exemplary embodiments are presented to illustrate aspects of mixing powders for use in PBF systems. For example, a powder that has been through a printing operation can be reused by mixing the reuse powder with new powder. In particular, if the reuse powder has a low level of contamination from the printing operation, the reuse powder may be mixed with a low percentage of new powder to be reused. On the other hand, if the reuse powder has a high level of contamination from the printing operation, the reuse powder may need to be mixed with a higher percentage of new powder. In various exemplary embodiments, the reuse powder can be dosed into a chamber of new powder, for example, based on a characteristic of the reuse powder, such as a level of contamination.
Various exemplary embodiments are presented to illustrate aspects of recovering powder after a printing operation. For example, a chamber positioned below the PBF apparatus can accept the metal powder that has not been fused after the printing operation. The chamber can include a characterizer that can determine a characteristic of the powder, such as a level of contamination. If the level of contamination is too high for reuse, the powder can be dumped through a first port in the chamber that leads to a recycling system that can, for example, melt the powder and create new powder from the liquid metal. If the level of contamination is not too high, the powder can be dumped through a second port that leads to a system that reuses the powder in the PBF apparatus. For example, the powder can be mixed with new powder as described in the paragraph above.
Various exemplary embodiments are presented to illustrate aspects of decontaminating powder. For example, a decontamination system can decontaminate powder that is going to be reused in the PBF apparatus. The decontamination system can include, for example, a furnace that heats the powder to decrease contaminants without melting the powder.
Furthermore, a powder recycling ecosystem can be created to recycle three-dimensional printed structures to create new powder for the PBF apparatus.
In many applications, the systems and methods disclosed herein can be implemented to reduce cost for PBF manufacturers and to reduce environmental impact of PBF manufacturing, thereby providing a more sustainable manufacturing platform for 3-D printed products.
Referring specifically to
In various embodiments, the deflector 105 can include one or more gimbals and actuators that can rotate and/or translate the energy beam source to position the energy beam. In various embodiments, energy beam source 103 and/or deflector 105 can modulate the energy beam, e.g., turn the energy beam on and off as the deflector scans so that the energy beam is applied only in the appropriate areas of the powder layer. For example, in various embodiments, the energy beam can be modulated by a digital signal processor (DSP).
Oxygen and humidity are examples of substances in air that can change a material property of powders used in PBF systems. In the exemplary cases described above, the changes to the material properties of the powder can also negatively impact the performance of the PBF system. For example, oxidized powder can result in build pieces that have impurities within their metal structure. Clumping powder can be difficult to transport, difficult to deposit, etc., and can result in clogged powder pathways, uneven powder layers, etc.
Fluorine is another example of a substance that can change a material property of powder. However, fluorine is not a common substance found in air. In particular, fluorine is an oxidizing agent for some metals and can cause a chemical change, which is a change in a material property.
In addition, there are some substances that can negatively impact the performance of a PBF system without necessarily changing a material property of the powder. For example, exposing the powder to carbon may not change a material property of the powder itself. However, when a build piece is formed from the powder and carbon mixture, a material property of the build piece can be different than a build piece formed from powder without carbon. For example, the carbon in the metal powder can affect the strength of the metal formed when the powder is fused. In addition, carbon can be reactive, e.g., can react with certain substances, when the build piece cools down. In various embodiments, environmental system 205 can decrease exposure of the metal powder to a substance that causes a material property of the build piece formed from fusing the powder to be different than the material property of a build piece formed from fusing powder not exposed to the substance. In some cases, such a substance does not change a material property of the powder itself
Additionally, some substances that can come in contact with the powder and get trapped and mixed with the powder can negatively impact the performance of the PBF system when the powder is heated to obtain melt pools. For example, some substances can cause the melt pool to spatter, to not form properly, etc. In these cases, a property of the build piece, e.g., a desired shape, can be different than a build piece formed from powder without these substances. In various embodiments, environmental system 205 can decrease exposure of the metal powder to a substance that causes a property of the build piece formed from fusing the powder to be different than the property of a build piece formed from fusing powder not exposed to the substance. In some cases, such a substance does not change a material property of the powder itself.
In sum, various embodiments of an environmental system can create an environment in a chamber that decreases exposure of the metal powder to a substance that changes a material property of the metal powder, decreases exposure of the metal powder to a substance that causes a material property of a build piece formed from fusing the metal powder to be different than the material property of a build piece formed from fusing metal powder not exposed to the substance, and/or decreases exposure of the metal powder to a substance that causes a property of a build piece formed from fusing the powder to be different than the property of a build piece formed from fusing powder not exposed to the substance.
Transporter 203 can transport the metal powder through the environment created by environmental system 205 in the chamber 201. In various embodiments, transporter 203 can be inside chamber 201, e.g., a conveyer belt, etc. In various embodiments, transporter 203 can be outside chamber 201, e.g., a vibrator that vibrates the chamber to move the powder.
In the example of
Chamber 503 can be tilted, and vibrator 505 can vibrate the chamber at a frequency that induces metal powder 501 to slide through the tilted chamber. It is noted that the flowability of metal powder 501 is due to liquefaction. Vibrator 505 is an example of a transporter that can be outside the chamber.
The mixture can be used in a PBF system, for example, and the mixing can be controlled to achieve a desired quality of the mixed powder for use in the PBF system. In various embodiments, either the first or the second powder can be new powder, and the other powder can be powder that has been recovered after a print operation because the powder was not fused during the print operation.
In various embodiments, the characteristic can include flowability. For example, a PBF system can require a minimum amount of flowability of the mixed powder, and the powders can be mixed based on a flowability characteristic in order to achieve the desired flowability of the mixed powder.
In various embodiments, the characteristic can include an amount of contamination. For example, a PBF system can require the mixed powder to have less than a maximum amount of contamination, and the powders can be mixed based on a characteristic that includes an amount of contamination in order to achieve less than the maximum amount of contamination of the mixed powder.
In various embodiments, the characteristic can include a print history. For example, the first powder can be new powder, and the second powder can be powder that has been recovered from a print operation of the PBF system. During a print operation, various factors can cause the not-fused powder to degrade. In this case, the recovered powder may have a reduced effectiveness due to being degraded by being used in one or more print operations. A PBF system can adjust the ratio of the first and second powders in the mixture based on how many times the second powder has been used in a print operation. In this way, for example, powder that has already been used in one or more print operations can be reused by mixing the powder with new powder in an appropriate ratio.
In various embodiments, the characteristic can include a print performance. For example, the first powder can be new powder, and the second powder can be powder that has been recovered from a print operation of the PBF system. During a print operation, the performance of the powder can be determined. In this case, the recovered powder may have performed well (e.g., allowed consistent melt pools to be formed) and, therefore, may be mixed at a higher ratio than a powder that did not perform well in the printing process.
Third chamber 811 can receive first metal powder 803 through an inlet pipe 815. In various embodiments, for example, inlet pipe 815 can be connected to a powder production system, such as powder production system 207, and first metal powder 803 can be new metal powder that is received from the powder production system through the inlet pipe.
Second chamber 807 can receive second metal powder 805 through an inlet pipe 817. In various embodiments, for example, inlet pipe 817 can be connected to a powder recovery system (examples of which are discussed below), and second metal powder 805 can be recovered metal powder that is received from the powder recovery system through the inlet pipe.
First and second metal powder mix 813 can exit first chamber 801 through an outlet pipe 819. In various embodiments, for example, outlet pipe 819 can be connected to a PBF apparatus, such as PBF apparatus 209, and first and second metal powder mix 813 can be delivered to the PBF apparatus through the outlet pipe.
Like exemplary apparatus 700, apparatus 800 can create a mixture of a first metal powder and a second metal powder based on a particular characteristic. The mixture can be used in a PBF system, for example, and the controlled mixing can account for a desired quality of the mixed powder for use in the PBF system.
In this example, first chamber 1001 is connected to a PBF apparatus 1021, such that mixed metal powder 1023 (i.e., the controlled mixture of first metal powder 1003 and second metal powder 1005) can be received by a depositor 1025 of the PBF apparatus. In this way, for example, PBF apparatus 1021 can be supplied with a controlled mixture of first metal powder 1003 and second metal powder 1005.
In various embodiments, characterizer 1015 can include, for example, a flowability determiner that determines flowability of the second metal powder, a contamination determiner that determines an amount of contamination of the second metal powder, a print history determiner that determines a print history of the second metal powder, a print performance determiner that determines a print performance of the second metal powder, etc.
Characterizer 1103 can determine a characteristic of powder 1115 and can send characteristic information to controller 1105. For example, characterizer 1103 can determine an amount of contamination of powder 1115. Based on the characteristic information, controller 1105 can determine whether to reuse powder 1115. For example, controller 1105 can determine whether powder 1115 is too contaminated to be reused. If controller 1105 determines powder 1115 should be reused, the controller can control first port 1109 to open (while second port 1111 remains closed) and can control transporter 1107 to move powder 1115 over the first port, so that the powder is dumped into a reuse pipe 1123. For example, if the powder is not too contaminated, the powder can be reused by the PBF apparatus. On the other hand, if controller 1105 determines powder 1115 should not be reused, the controller can control second port 1111 to open (while first port 1109 remains closed) and can control transporter 1107 to move powder 1115 over the second port, so that the powder is dumped into a recycle pipe 1125. For example, if the powder is too contaminated to be reused, the powder can be recycled to create new powder for the PBF apparatus. In this way, for example, powder that has been through a print operation of a PBF apparatus can be reused, recycled, etc., based on a determination of whether the powder is suitable for reusing, recycling, etc., which can reduce waste and reduce the cost of operating PBF systems.
If powder recovery apparatus 1507 determines to reuse powder 1505, the powder can be deposited in a pipe of reuse powder 1511. Reuse powder 1511 can be transported to a decontamination system 1515, such as decontamination system 1300 of
On the other hand, if powder recovery apparatus 1507 determines not to reuse powder 1505, the powder can be deposited in a pipe of recycle powder 1531. PBF system 1500 can transport recycle powder 1531 to a metal atomizer 1533, which can heat and melt the recycle powder to create new (recycled) powder 1523. PBF system 1500 can transport the new (recycled) powder to powder pipe 1527 for mixing with decontaminated powder 1517.
PBF system 1500 can include an environmental system 1535 that can create an environment that decreases exposure of the powder to a substance that changes a material property of the metal powder. For example, environmental system 1535 can operate in a similar way as environmental system 205 of
In various embodiments, the powder transport, handling, and use can be accomplished in a closed system, e.g., an air-tight system. In various embodiments, air-locks can be positioned between different sections of the closed system so that a section can be sealed off from other sections, e.g., so that the section can be accessed from the outside while maintaining the environment in the remaining sections. In various embodiments, build pieces can be inspected, and rejected build pieces can be recycled along with the recycled powder. Thus, various exemplary embodiments described above and other embodiments can allow the efficient reuse, recycling, etc., of powder and can offer cost savings for PBF systems and reduce negative environmental impact of such systems.
When car 1609 is built as a new car, part 1608 is also new. In powder recycling ecosystem 1600, part 1608 can be returned to PBF system 1601 when the part has served its purpose. For example, part 1608 can be returned if the part fails, if the part is replaced during routine maintenance, at the end of life of car 1609 (as shown in the example of
The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these exemplary embodiments presented throughout this disclosure will be readily apparent to those skilled in the art. Thus, the claims are not intended to be limited to the exemplary embodiments presented throughout the disclosure, but are to be accorded the full scope consistent with the language claims. All structural and functional equivalents to the elements of the exemplary embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112(f), or analogous law in applicable jurisdictions, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”