The present disclosure relates to additive manufacturing systems and processes, and more particularly to an additive manufacturing system and method which delivers a powdered material suspended in a solution to a surface, after which the solution evaporates leaving just the powdered material, which is then melted by a heat source to form a material layer of a part.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Current powder delivery systems for additive manufacturing (“AM”) processes such as Selective Laser Sintering (“SLS”), Direct Metal Laser Sintering (“DMLS”), or Diode based Additive Manufacturing use a single type or composition of powder per part. The powder is swept over a lowered part creation zone creating a layer of powder of a specified thickness.
As layer upon layer of material is deposited in a traditional SLS or DMLS system, the part being created grows thicker and thicker. For the first few initial layers of part creation, the heat delivered to melt the material is removed by conduction to the base substrate that the powder is initially deposited on. As the part becomes thicker and thicker, this conduction pathway becomes insufficient at removing the excess heat in the part. As a result, the part begins to rise in temperature. The temperature of the part continues to increase as successive materials layers are melted, until the part eventually reaches a temperature which is just below the melting point of the powder. Accordingly, cooling the part to permit the continued application of material layers typically becomes a significant challenge. Complicating this is the desire to be able to fully complete the manufacture of the part, using the AM manufacturing process, in as short a time as possible.
Also, in traditional SLS or DMLS systems, the powder bed is filled with the powder to be melted, as well as a portion of the powder which is not melted. This can result in the powder bed being required to support significant weight when heavy and/or dense powdered material types are being used.
The present disclosure relates to a system for manufacturing a part via an additive manufacturing process. The system may comprise a reservoir for containing a heated solution forming a mixture of a volatile component and meltable powdered material particles, the heated solution being heated to a point where the heated solution is at least about to begin boiling. A nozzle is included which is operably associated with the reservoir for channeling a quantity of the heated solution onto at least one of a substrate or a previously formed material layer. A processor is included which is configured to control flow of the heated solution through the nozzle to enable the heated solution to be flowed onto at least one of the substrate or the previously formed material layer. A heat source is included which is responsive to the processor for generating heat sufficient to melt the meltable powdered material particles. The heat source is controlled to melt the meltable powdered material particles in the quantity of the heated solution flowed onto at least one of the substrate or a previously formed material layer after the volatile component has at least substantially evaporated from the mixture. The volatile component operates to cool a previously formed material layer before heating of the meltable powdered material particles takes place, and wherein the heating of the meltable powdered material particles fuses the meltable powdered material particles into a single structural layer. The part is thus formed exclusively by the meltable powdered material particles.
In another aspect the present disclosure relates to a system for manufacturing a part via an additive manufacturing process. The system may comprise a reservoir for containing a heated solution forming a mixture of a volatile component and meltable powdered material particles, the heated solution being heated to a point where the heated solution is at least about to begin boiling. A nozzle is included which is operably associated with the reservoir for channeling a quantity of the heated solution onto at least one of a substrate or a previously formed material layer. A processor is included which is configured to control flow of the heated solution through the nozzle to enable the heated solution to be flowed onto at least one of the substrate or the previously formed material layer. A heat source is included which is responsive to the processor for generating heat sufficient to melt the meltable powdered material particles. The heat source is controlled to melt the meltable powdered material particles in the quantity of the heated solution flowed onto at least one of the substrate or a previously formed material layer after an expiration of a predetermined time period sufficient to enable the volatile component to be at least substantially evaporated from the mixture. The volatile component provides a cooling effect on a previously deposited material layer of a part being formed in a layer by layer process, and such that the cooling takes place intermittently with every application of a new quantity of the meltable powdered material particles about to be fused to form a new structural layer of the structural part. The heating of the meltable powdered material particles fuses the meltable powdered material particles, layer by layer, into a single structural layer, and the part is formed exclusively by the meltable powdered material particles.
In still another aspect the present disclosure relates to a system for manufacturing a part via an additive manufacturing process. The system comprises a first reservoir for containing a first heated solution forming a mixture of a first volatile component and a quantity of first meltable powdered material particles. The system also comprises a first nozzle operably associated with the first reservoir for channeling a quantity of the heated solution onto at least one of a substrate or a previously formed material layer. A second reservoir is included for containing a second heated solution forming a second mixture of a second volatile component and a quantity of second meltable powdered material particles. A second nozzle is included which is operably associated with the second reservoir to channeling a quantity of the second heated solution onto at least one of the substrate or the previously formed material layer. A processor is included which is configured to control flow of the flows of the first heated solution through the first nozzle and the second heated solution through the second nozzle, to enable the first and second heated solutions to be flowed onto at least one of the substrate or the previously formed material layer. A laser is included which is configured to produce an optical signal. The laser is responsive to the processor and the optical signal generates heat sufficient to melt the quantities of first and second meltable powdered material particles. The laser is controlled to melt the quantities of first and second meltable powdered material particles in the first and second heated solutions flowed onto at least one of the substrate or a previously formed material layer after an expiration of a predetermined time period sufficient to enable the volatile components in the quantities of first and second heated solutions to be at least substantially evaporated. The volatile component of each of the first and second heated solutions provides a cooling effect on a previously deposited material layer of a part being formed in a layer by layer process, and such that the cooling takes place intermittently with every application of a new quantity of the first meltable powdered material particles and the second meltable powdered material particles about to be fused to form a new structural layer of the structural part. The heating of the meltable powdered material particles fuses the meltable powdered material particles, layer by layer, into a single structural layer, and the part is formed exclusively by the meltable powdered material particles.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
The system and method of the present disclosure makes use of a cooling mechanism in the form of a volatile solvent. The volatile solvent acts as a carrier fluid for material particles which are deposited on a substrate, or on a previously formed layer, during an additive manufacturing (“AM”) process. The latent heat of vaporization of the fluid is capable of removing a great deal of heat and can effectively cool the surface of the part where it sees the thermal heat flux, and is the hottest.
Referring to
While three nozzles 12-16 are illustrated, the system 10 is not limited to use with any particular number of different nozzles or material types. Thus, it is expected that the desired material qualities and/or the specific type of part being manufactured may dictate whether one, two, three or more different material types will be chosen/required for making a specific part.
Each of the nozzles 12-16 includes an associated reservoir R1, R2 and R3, where a specific solution is contained that is deposited through its associated nozzle 12-16. Operation of the deposition of the solution from each nozzle 12-16 may be controlled by a processor 18 by opening and closing suitable valves V1, V2 and V3 associated with the nozzles 12-16. The processor 18 may also control a suitable heat source 20 for melting the particles of powdered material 22a-22c in each of the solutions 12a-16a after each is deposited on a substrate. The heat source 20 may comprise any device suitable for providing the required heat to melt the particles 22a-22c. For example, the heat source 20 may be formed by a laser or a diode laser light source. A high powered diode laser system that may be suitable for use in forming the system 10 is disclosed in co-pending U.S. patent application Ser. No. 13/785,484, filed Mar. 5, 2013 (U.S. Pub. No. 2014/0252687), and assigned to Lawrence Livermore Security LLC, the teachings of which are hereby incorporated by reference into the present disclosure.
The processor 18 may include suitable software 18a which includes information stored in a non-volatile memory, for example a lookup table 18c stored in non-volatile random access memory 18b, on specific temperatures and/or durations that need to be delivered to melt the particles of powdered material 22a-22c in each solution 12a-16a. As such, the delivery of optical power can be specifically “tuned” to the specific types of particles mixed into each of the solutions 12a-16a in order to melt the different types of particles within a determined time frame. The solutions 12a-16a in
Each solution 12a-12c is applied to a substrate 26 (or to a previously formed material layer) while the solution 24a-24c is at, or nearly at, its boiling point. As a result of the latent heat of vaporization, the volatile component 24a-24c of each solution 12a-12c then evaporates, leaving just the previously suspended particles of powdered material 22a-22b on the substrate 26 (or previously formed material layer) in the desired configuration. Importantly, the latent heat of evaporation effectively helps to cool the surface, that is either the substrate 26 or the surface of the previously formed layer(s), in the process.
Similar to how an inkjet printer delivers multi-colored ink, the system 10 is able to deliver multiple types of powdered materials. The powder layer remaining after the volatile component 24a-24c of each solution 12a-12c evaporates may be melted with the heat source 20 using a predetermined amount of energy selected for the specific type of powdered material. Thus, different types of particles of powdered material may have different amounts/levels of heat used to accomplish the melting of the particles thereof. The next layer of solution 12a-12c can then be deposited onto the surface of the just-formed layer and the material powder 22a-22b subsequently melted using the heat source 20. The evaporative cooling caused by the latent heat of vaporization of the volatile component 24a-24c of each solution 12a-12c keeps the surface of the previously formed material layer, and thus the part that is being produced, at a relatively constant temperature. This is an important benefit because it helps to maintain the entire part at an acceptable temperature as one layer after another of the part is built up using the system 10. As AM processes increase in speed in the years to come, the waste process heat might be such that the manufacturing process will need to periodically stop to give the part time to cool down. This technique would eliminate that need.
A particularly significant advantage of the system 10 is that it enables the manufacturing of parts containing many different materials to be fabricated in a single layer at once, or substantially at once. Thus, as an example, portions of a part that may require additional strength may be formed from one or more types of powdered material while other portions of the part requiring less strength can be formed using different types of powdered material. The ability to form a single part from a plurality of different powdered materials, and to be able to control where each powdered material is deposited, enables the physical properties of the produced part to be closely tailored to meet specific performance requirements (e.g., durability, longevity, thermal tolerance, stress tolerance, etc.) for the produced part.
The system 10 also enables potentially faster powder deposition over traditional “sweeping” methods typically employed in an AM process. In such traditional methods, typically one raster scan of material is laid down, with a plurality of scans (sometimes dozens or even hundreds) being required to form a single material layer. The system 10 enables multiple materials to be “printed” simultaneously, or virtually simultaneously, using the heat source 20 to form an entire layer of the part at one time or substantially at one time. The ability to cool the underlying surface on which the newest layer of solution 12a-12c has been applied, using the evaporative cooling which results from the latent heat of vaporization of the volatile components 24a-24c, allows cooling to be achieved at those locations on the part where the cooling is needed the most.
While a bed of powder may still be necessary for support, the bed can be made of materials that are of low cost while high cost materials can still be used in the layer that form portions of the actual part being produced. This eliminates the need to have a powder bed full of the material that is to be printed, especially if the printed part is small relative to the bed size, the material to be printed is expensive, or of high density. The nozzles 12a-12c can be rastered across the powder bed using the processor 18, printing (i.e., depositing) either only where material is desired, or printing material where desired to melt, and using a less expensive or lighter weight filler material everywhere else. In this regard it will be appreciated that by being able to use different types of powdered materials, the system 10 may potentially enable a part to be produced which is lighter than what would otherwise be the case with an AM formed part made from a single material.
Referring to
At operation 106 the heat source 20 may then be used to melt the powdered materials 22a-22c. The melting may be performed across the entire material layer substantially at once, rather than by raster scanning the heat source 20 back and forth over the substrate 26. This significantly expedites the formation of each layer of the part. As the melting of the powdered materials 22a-22c occurs, the particles of each type of material are fused together. Thus, any portions where powdered materials 22a remain will be fused into a solid section of the material layer, and the same will occur for powdered materials 22b and 22c.
At operation 108, a check is made by the processor 18 if the entire part has been completed, and if not, then operations 104-108 are re-performed as many times as needed to form the entire part, layer by layer. Once the check at operation 108 indicates that the part is completely formed, the AM process is then complete.
The system 10 and method thus allows for a plurality of powdered materials to be deposited, simultaneously, at each layer of a part to tailor the use of materials to the physical characteristics that are needed for the part. The latent heat of vaporization of the fluid also enables the part to be maintained at a reasonably consistent temperature during the AM process, which would otherwise be difficult or impossible to achieve with a conventional AM process.
While various embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the present disclosure. The examples illustrate the various embodiments and are not intended to limit the present disclosure. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.
This application is a divisional and claims priority of U.S. patent application Ser. No. 16/989,463, filed Aug. 10, 2020 and presently allowed, which in turn claims priority from U.S. patent application Ser. No. 14/504,646 filed on Oct. 2, 2014. The entire disclosure of each of the above applications is incorporated herein by reference.
This invention was made with Government support under Contract No. DE-AC52-07NA27344 awarded by the United States Department of Energy. The Government has certain rights in the invention.
Number | Date | Country | |
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Parent | 16989463 | Aug 2020 | US |
Child | 17744721 | US | |
Parent | 14504646 | Oct 2014 | US |
Child | 16989463 | US |