Patent Application
20240425963
The present teachings relate generally to printing bimetallic components and, more particularly, to a system and method for printing bimetallic components.
A drop-on-demand (DOD) or three-dimensional (3D) printer builds (e.g., prints) a 3D object from a computer-aided design (CAD) model, usually by successively depositing material layer upon layer. A drop-on-demand (DOD) printer, for example, one that prints a metal or metal alloy, ejects a small drop of liquid metal alloy when a firing pulse is applied. Using this technology or others using various printing materials, a 3D part can be created by ejecting a series of drops which bond together to form a continuous part. For example, a first layer may be deposited upon a substrate, and then a second layer may be deposited upon the first layer. One particular type of 3D printer is a magnetohydrodynamic (MHD) printer, which is suitable for jetting liquid metal layer upon layer which bond together to form a 3D metallic object. Magnetohydrodynamic refers to the study of the magnetic properties and the behavior of electrically conducting fluids.
Furthermore, 3D printing technology is well known for enabling the manufacture of complex 3D designs which otherwise could not be made using traditional methods such as machining, casting, or injection molding. The joining or fabrication of dissimilar metallic materials has traditionally been accomplished by processes such as welding and brazing, though simple geometries and thin coatings over an entire material can be achieved through cladding, thermal spray, or plating processes. More recently, directed energy deposition (DED) additive manufacturing processes have been used for the same purposes. However, each of these processes has distinct limitations with respect to materials capable of being joined, stresses induced during processing, for example, deformation, bond strength, and service temperature.
Thus, a method of and apparatus for forming composite parts of dissimilar metallic materials with the use of a drop-on-demand or 3D ejector system is needed to produce a wider variety of features or functions in formed or cladded composite parts while avoiding issues associated with previously known methods and materials.
The following presents a simplified summary in order to provide a basic understanding of some aspects of one or more embodiments of the present teachings. This summary is not an extensive overview, nor is it intended to identify key or critical elements of the present teachings, nor to delineate the scope of the disclosure. Rather, its primary purpose is merely to present one or more concepts in simplified form as a prelude to the detailed description presented later.
A method of forming a bimetallic composite is disclosed, including positioning a first metal in proximity to an ejector for jetting a material. The method of forming a bimetallic composite also includes ejecting one or more drops of the liquid material to form a layer of the liquid material onto a surface of the first metal. The method of forming a bimetallic composite also includes where the liquid material may include a second metal. Implementations of the method of forming a bimetallic composite may include where the first metal can include iron, chrome, or a combination thereof. The second metal can include a metal, a metallic alloy, or a combination thereof. The second metal can include aluminum. The first metal is heated prior to ejecting one or more drops of the liquid material. The first metal is heated to a temperature from about 550° C. to about 1200° C. The method of forming a bimetallic composite may include applying an adhesive to a surface of the first metal prior to ejecting one or more drops of the liquid material. The method of forming a bimetallic composite may include forming an oxide layer onto a surface of the first metal prior to ejecting one or more drops of the liquid material. The second metal can be a liquid when first contacting the first metal, and a reduction potential of the first metal and a reduction potential of the second metal are such that a spontaneous reaction occurs between the first metal and the second metal when in contact.
A metal cladding process is disclosed, including positioning a component in proximity to an ejector for jetting a liquid material. The process also includes ejecting one or more drops of the liquid material to form a layer of the liquid material onto a surface of the component. The process also includes where the liquid material may include a second metal. Implementations of the metal cladding process can include where the component includes a first metal, such as iron, chrome, or a combination thereof. The first metal is heated to a temperature from about 550° C. to about 1200° C. prior to ejecting one or more drops of the liquid material. The metal cladding process may include applying an adhesive to a surface of the first metal prior to ejecting one or more drops of the liquid material. The metal cladding process may include forming an oxide layer onto a surface of the first metal prior to ejecting one or more drops of the liquid material. The second metal can be a liquid when first contacting the first metal, and a reduction potential of the first metal and a reduction potential of the second metal are such that a spontaneous reaction occurs between the first metal and the second metal when in contact. The second metal may include a metal, a metallic alloy, or a combination thereof. The second metal may include aluminum.
A metal cladding system is disclosed, including an ejector for jetting a liquid material, and a platform for conveying a component in proximity to the ejector. The system also includes where the system also includes an ejector configured to eject one or more drops of the liquid material to form a layer of the liquid material onto a surface of the component. The system also includes a platform configured to heat the component. Implementations of the metal cladding system may include where the liquid material is a metal, a metallic alloy, or a combination thereof.
The features, functions, and advantages that have been discussed can be achieved independently in various implementations or can be combined in yet other implementations further details of which can be seen with reference to the following description.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings and together with the description, serve to explain the principles of the disclosure. In the figures:
It should be noted that some details of the figures have been simplified and are drawn to facilitate understanding of the present teachings rather than to maintain strict structural accuracy, detail, and scale.
Reference will now be made in detail to exemplary embodiments of the present teachings, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same, similar, or like parts.
When design or performance criteria of three-dimensional parts fabricated by additive manufacturing techniques require the joining of materials, this joining of materials can be accomplished through an elevated temperature liquid metal deposition process, thereby creating a low-stress multi-material component. Furthermore, with the adjustment of system parameters or components, the bonding between materials can be achieved either through solid-state mechanisms, such as diffusion, limited remelting (similar to welding), adhesion. or a combination thereof. Unlike traditional joining processes, which require surfaces of oxidation-prone materials to be appreciably free of oxidation prior to joining in order to achieve strong bonds, liquid metal deposition processes are more tolerant of this oxidation. The use of tailored chemical additions to the metallic materials being joined can facilitate bonding and, in some cases, in situ reduction of oxide films.
The present disclosure provides a system and method for producing a metallic material deposited onto a metallic substrate (i.e. a functional part or raw material which will be converted into a functional part) via a liquid metal additive manufacturing process. The present teachings include the deposition of a metallic alloy such as aluminum, copper, or nickel, onto a heated surface to create a fused composite part. The base mechanism for bonding produced by this deposition process can be caused by an interfacial chemical reaction at the drop-substrate interface, and does not necessarily require remelting of the substrate. In addition, heat treatment or other adhesion or attachment techniques may be used to induce interdiffusion and increase the bond strength between materials. Certain alloying elements such as aluminum, magnesium, lithium, titanium, or silicon can alternatively be introduced into the print medium based on their reduction potentials with respect to the substrate chemistry. Examples of the present teachings can include printed aluminum onto surfaces of a high chromium stainless steel which causes a reduction of surface chromium oxide to provide a fused composite part. According to the reduction potential table, aluminum will work on other surfaces covered with oxides of other metals such as Zn, Ni and Fe and similar metals having reduction potentials below aluminum.
The 3D printer 100 may also include a power source, not shown herein, and one or more metallic coils 106 enclosed in a pump heater that are wrapped at least partially around the ejector 104. The power source may be coupled to the coils 106 and configured to provide an electrical current to the coils 106. An increasing magnetic field caused by the coils 106 may cause an electromotive force within the ejector 104, that in turn causes an induced electrical current in the printing material 126. The magnetic field and the induced electrical current in the printing material 126 may create a radially inward force on the printing material 126, known as a Lorenz force. The Lorenz force creates a pressure at an inlet of a nozzle 110 of the ejector 104. The pressure causes the printing material 126 to be jetted through the nozzle 110 in the form of one or more liquid drops 128.
The 3D printer 100 may also include a substrate 144, that is positioned proximate to (e.g., below) the nozzle 110. The substrate 144 may include a heating element, or alternatively be constructed of brass or other materials. In certain examples, the substrate 144 may further include a build plate made of brass which can be coated with nickel to promote the wetting of molten aluminum droplets when they impinge on the build plate. The ejected drops 128 may land on the substrate 144 and solidify to produce a 3D object. The 3D printer 100 may also include a substrate control motor that is configured to move the substrate 144 while the drops 128 are being jetted through the nozzle 110, or during pauses between when the drops 128 are being jetted through the nozzle 110, to cause the 3D object to have the desired shape and size. The substrate control motor may be configured to move the substrate 144 in one dimension (e.g., along an X axis), in two dimensions (e.g., along the X axis and a Y axis), or in three dimensions (e.g., along the X axis, the Y axis, and a Z axis). In another example, the ejector 104 and/or the nozzle 110 may be also or instead be configured to move in one, two, or three dimensions. In other words, the substrate 144 may be moved under a stationary nozzle 110, or the nozzle 110 may be moved above a stationary substrate 144. In yet another example, there may be relative rotation between the nozzle 110 and the substrate 144 around one or two additional axes, such that there is four or five axis position control. In certain examples, both the nozzle 110 and the substrate 144 may move. For example, the substrate 144 may move in X and Y directions, while the nozzle 110 moves up and/or down in a Z direction. In case of a nozzle 110 moving, the nozzle 110 and other printhead assembly components can include a nozzle or printhead motor control, not shown herein. The substrate 144 may alternatively be referred to as a platform, which can be stationary relative to a nozzle or ejector, or the platform can translate relative to a nozzle or ejector. In examples, the platform can comprise a part or component finished in a separate printer or system which can be introduced into the printer or metal cladding system of the present disclosure for cladding with a similar or different metal-based material as described herein.
The 3D printer 100 may also include one or more gas-controlling devices, which may be or include a gas source 138. The gas source 138 may be configured to introduce a gas. The gas may be or include an inert gas, such as helium, neon, argon, krypton, and/or xenon. In another example, the gas may be or include nitrogen. The gas may include less than about 10% oxygen, less than about 5% oxygen, or less than about 1% oxygen. In at least one example, the gas may be introduced via a gas line 142 which includes a gas regulator 140 configured to regulate the flow or flow rate of one or more gases introduced into the three-dimensional 3D printer 100 from the gas source 138. For example, the gas may be introduced at a location that is above the nozzle 110 and/or the heating element 112. This may allow the gas (e.g., argon) to form a shroud/sheath around the nozzle 110, the drops 128, the 3D object, and/or the substrate 144 to reduce/prevent the formation of oxide (e.g., aluminum oxide) in the form of an air shield 114. Controlling the temperature of the gas may also or instead help to control (e.g., minimize) the rate that the oxide formation occurs.
The liquid ejector jet system 100 may also include an enclosure 102 that defines an inner volume (also referred to as an atmosphere). In one example, the enclosure 102 may be hermetically sealed. In another example, the enclosure 102 may not be hermetically sealed. In one example, the ejector 104, the heating elements 112, the power source, the coils, the substrate 144, additional system elements, or a combination thereof may be positioned at least partially within the enclosure 102. In another example, the ejector 104, the heating elements 112, the power source, the coils, the substrate 144, additional system elements, or a combination thereof may be positioned at least partially outside of the enclosure 102. While the liquid ejector jet system 100 shown in
Printing systems as described herein may alternatively include other printing materials such as plastics or other ductile materials that are non-metals. The print material may include a metal, a metallic alloy, or a combination thereof. A non-limiting example of a printing material may include aluminum. Exemplary examples of printing systems of the present disclosure may include an ejector for jetting a print material, including a structure defining an inner cavity, and a nozzle orifice in connection with the inner cavity and configured to eject one or more droplets of liquid print material, wherein the ejector is configured to print a first layer of a three-dimensional printed part from a standoff position relative to the substrate 144 and the ejector is configured to print one or more remaining layers onto the first layer from a z-height position relative to a top surface of the first layer. In implementations, a first material 148 may be disposed on the substrate 144. This first material 148 can be in the form of a three-dimensional part or material that has previously been printed or formed by a similar printing system 100 or be produced by other means, such as extrusion, machining, or other fabrication methods. The first material 148 can be a metal as described herein, such as, but not limited to, aluminum, gold, silver, nickel, copper, iron, chromium, chrome, stainless steel, brass, bronze, or alloys or combinations thereof. The printing system 100 is further configured to eject one or more drops of a second print material 146, in certain examples present as a liquid material upon ejection to form a layer of the liquid second print material 146 onto a surface of the first material 148. In examples, the liquid second material 146 includes a metal, as described herein, such as, but not limited to, aluminum, gold, silver, nickel, copper, iron, chromium, chrome, stainless steel, brass, bronze, or alloys or combinations thereof. In examples, the first material 148 and the second print material 146 are different materials, while in other examples, the first material 148 and the second print material 146 have common ingredients or metals within their compositions. In still other examples, the first material 148 can be heated prior to ejecting one or more drops of the liquid second print material 146. The liquid second print material 146 can form a solid layer of metal or metal cladding layer 150 on a surface of the first material 148. The bonding of the metal cladding layer 150 to the surface of the first material 148 can be enhanced by the use of an attachment system 152 that can be either internal or external to the printing system 100. In certain examples, the attachment system can be employed prior to or during deposition of the liquid second print material 146 to introduce an element 154 to an interface between the surface of the first material 148 and the liquid second print material 146. Certain examples of attachment can include thermoforming techniques, such as, but not limited to welding. Attaching techniques that comprise welding can employ any welding techniques that are suitable for welding metals, such as, for example, ultrasonic welding, induction welding, or laser welding, all of which are generally well known in the art. The welds can be made in seams or at selective spot welding locations, as is also generally well known in the welding art. Further attachment techniques can include at least one technique selected from the group consisting of i) an adhesive between the first material 148 and the liquid second print material 146 or the metal cladding layer 150; ii) mechanical fasteners that temporarily anchor or fasten the metal cladding layer 150 to the three-dimensional part made of the first material 148; iii) thermoforming the three-dimensional part made of the first material 148 so that the shape of the three-dimensional part made of the first material 148 wraps more than 180° around the metal cladding layer 150 in a manner so that the metal cladding layer 150 is captured onto the three-dimensional part; and iv) welding the metal cladding layer 150 to the three-dimensional part made of the first material 148 using a welding process that is suitable for welding the first print material and the second print material to one another.
The present disclosure provides a system and methods directed to achieving enhanced adhesion or bonding between different metal compositions during a build of a three-dimensional structure or part. A “metal composition” may refer to a single metal, or an alloy, a metal or alloy having an additive to participate in a bonding or adhesion reaction, or a combination thereof. Specifically, for oxidation-prone metal materials, good bonding can be obtained through reduction of the metal ions in the oxide layer to its metallic form, effectively destroying or breaking the physical barrier. For example, for high chromium content stainless steel, the surface can be oxidized (in forms of Cr3+ in Cr2O3). Traditional physical means, such as remelting or soldering to achieve bonding of dissimilar metal composition could be negatively impacted by this oxide layer. In examples of the present disclosure, liquid aluminum can react with the ionic chromium Cr3+ and reduce the chromium to its metallic, elemental form of Cr, since Al is a stronger reducing agent according to a standard reduction potential table. This reaction can be simplified as: Cr3++Al→Cr+Al3+. The reduced metallic chromium would be readily exposed to the incoming liquid aluminum and form effective metallic bonding via chemical reaction.
In terms of a generalized reaction description, an existing part either introduced to the system as part fabricated externally or fabricated in a system of the present disclosure using a first metal, feed material or printing includes a surface metallic oxide layer, where metal X is in its ionic form of Xn+. A second metal, feed material, or print material incoming to the system and being subsequently deposited upon the existing three-dimensional part includes or comprises at least one secondary element Y which is a stronger reduction agent, as compared to X, such that Y will reduce Xn+ to its metallic form X. The initial barrier on the three-dimensional part formed by the oxide layer is destroyed or transformed and X will form adhesive chemical bonding with the incoming liquid metal/alloy of the second feed material or print material. Y could be the main metallic component of the alloy of the second print material, or one of the main alloying elements of the alloy. In some cases, Y could be an additive, specifically added to the second print material metal or alloy to enhance bonding. In still other examples, more than one secondary element Y, for example designated Y1, Y2, Y3, and so on, can be added to the second print material in order to produce chemical bonding in a bimetallic structure by a similar reaction as described herein. In examples, X can represent metals such as X,X,X, or combinations thereof while Y could represent metals such as Y,Y, Y, or combinations thereof. According to the reduction potential table, for example, the following metals are arrange in an descending order according to their reduction strength: Ca, Na, Mg, Al, Mn, Zn, Cr, Fe, Ni, Sn, Cu. The pairing example of [X,Y] can be any pair with X trailing Y in the list. [Cr, Al] is one example described earlier. Other examples such as [Ni, Al], [Sn, Mg] also satisfy the condition.
In examples, 6061 aluminum alloy bonded, as a second liquid metal was deposited onto a pre-formed three-dimensional part composed of 410 stainless-steel. In another example, 4008 Aluminum bonded as a second liquid metal was deposited onto a three-dimensional part composed of 6061 Aluminum and 410 stainless-steel. The second liquid metal, in examples, was deposited on the substrate composed of the three-dimensional part. In these examples, a shadow structure of approximately 1 cm was bonded to a stainless-steel substrate, or pre-existing three-dimensional part. In certain examples, the substrate could be a three-dimensional part that is coated with a secondary build or print material. The second printing material or jetted material can be selected depending upon the substrate or part made from a first material. Certain examples can employ an adhesive layer or another material layer on the substrate to enhance adhesion. In other examples, the substrate can remain partially melted during cooling, and if an ejected or deposited droplet of a second print material possesses sufficient heat, the two materials together can be welded or blended by melting together. In other examples, a redox reaction process or oxide reduction process occurs when the second liquid print material is deposited onto the first material. For example, stainless-steel SS 410 has a relatively high chromium content or CrOx layer on the surface. As the stainless-steel does not melt upon exposure to a molten drop of aluminum, due to a melting temperature mismatch, there is an oxide reduction process that takes place, where the chromium metal and aluminum droplet will react and combine with the oxide to form a bonding between the two materials. Furthermore, the reduction potentials of various metals of the first printing material and of the second printing material can be arranged in such a way that there is a spontaneous reaction between the two metals during the cladding or deposition processes, where an initial step may be to form an oxide on the substrate surface prior to or during a deposition of a liquid print material onto a substrate or three-dimensional part. Such a reaction should be spontaneous. In still other examples, a secondary attachment technique such as those described herein can be utilized. An attaching technique that involves thermoforming the metal cladding layer of the second print material can be utilized. Attaching techniques that comprise welding can employ any suitable welding techniques, such as, for example, ultrasonic welding, induction welding, or laser welding, all of which are generally well known in the art. The welds can be made in seams or at selective spot-welding locations, as is also generally well known in the welding art. In this manner, one or multiple layers of cladding can be provided onto a surface of a three-dimensional part. The one or more multiple layers of metal cladding can be the same material or can be composed of different materials or metals or metal alloys.
While the present teachings have been illustrated with respect to one or more implementations, alterations and/or modifications may be made to the illustrated examples without departing from the spirit and scope of the appended claims. For example, it may be appreciated that while the process is described as a series of acts or events, the present teachings are not limited by the ordering of such acts or events. Some acts may occur in different orders and/or concurrently with other acts or events apart from those described herein. Also, not all process stages may be required to implement a methodology in accordance with one or more aspects or embodiments of the present teachings. It may be appreciated that structural objects and/or processing stages may be added, or existing structural objects and/or processing stages may be removed or modified. Further, one or more of the acts depicted herein may be carried out in one or more separate acts and/or phases. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” The term “at least one of” is used to mean one or more of the listed items may be selected. Further, in the discussion and claims herein, the term “on” used with respect to two materials, one “on” the other, means at least some contact between the materials, while “over” means the materials are in proximity, but possibly with one or more additional intervening materials such that contact is possible but not required. Neither “on” nor “over” implies any directionality as used herein. The term “conformal” describes a coating material in which angles of the underlying material are preserved by the conformal material. The term “about” indicates that the value listed may be somewhat altered, as long as the alteration does not result in nonconformance of the process or structure to the illustrated embodiment. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.” Finally, the terms “exemplary” or “illustrative” indicate the description is used as an example, rather than implying that it is an ideal. Other embodiments of the present teachings may be apparent to those skilled in the art from consideration of the specification and practice of the disclosure herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the present teachings being indicated by the following claims.
