Patent ID: 12247312

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure relates to a mandrel used in electrodeposition having an actively cooled internal core. For purposes of illustration, the aspects of the disclosure discussed herein will be described with a mandrel used during an electroforming process. It will be understood, however, that the disclosure as discussed herein is not so limited and may have general applicability within forms utilized for electroforming processes and cooling in tool dies.

All directional references (e.g., radial, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise) are only used for identification purposes to aid the reader's understanding of the disclosure, and do not create limitations, particularly as to the position, orientation, or use thereof. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order, and relative sizes reflected in the drawings attached hereto can vary.

An electroforming process for forming a metallic component38(shown in dashed line) is illustrated by way of an electrodeposition bath40inFIG.1. An exemplary bath tank50carries a conductive electrolytic fluid solution52. The electrolytic fluid solution52, in one non-limiting example, can include aluminum alloy carrying alloying metal ions. In one alternative, non-limiting example, the electrolytic fluid solution52can include a nickel alloy carrying alloying metal ions.

An anode54spaced from a cathode56is provided in the bath tank50. The anode54can be a sacrificial anode or an inert anode. While one anode54is shown, it should be understood that the bath tank50can include any number of anodes54as desired. The cathode56can be a mandrel58coated in an electrically conductive material62, including, by way of non-limiting examples, copper, silver, or nickel. The mandrel58defines a body60formed from, by way of non-limiting example, structural wax and including a cooling core82. The body can be made of a reclaimable material, such as the structural wax, where a reclaimable material is one that can be collected after an electroforming process and reused as another body in another electroforming process. For example, the structural wax can be melted from the electroformed component at heightened temperatures to reclaim the material forming the body60after the electroforming process. Suitable reclaimable materials can include waxes, plastics, polymer foams, metals, or deformable materials, which as those collectible via melting or leeching in non-limiting examples. Carbon fiber or graphene nano-particles can be used to increase thermal and electrical conductivity of wax and polymer mandrels. The addition of these particles will increase the thermal performance and resistance of slumping or deformation of the composite material. It is further contemplated that a conductive spray or similar treatment can be provided to the mandrel58to facilitate formation of the cathode56. This initial conductive layer is typically thin, with significant variation in thickness over large surface areas. For larger mandrels with complex shapes, this variation will affect early-stage current density distribution across the mandrel surface. Strategic placement of multiple electrical contact locations to the cathodic surface is critical to reduce electrical potential differences. This condition is removed by use of an electrically conductive mandrel that is in continuous, uniformly distributed electrical contact with an electrically conductive coolant core tube with end electrical isolators or couplers. In addition, while illustrated as one cathode56, it should be appreciated that one or more cathodes are contemplated for use in the bath tank50.

A controller64, which can include a power supply, can be electrically coupled to the anode54and the cathode56by electrical conduits66to form a circuit67via the electrolytic fluid solution52. Optionally, a switch68or sub-controller can be included along the electrical conduits66, and can be positioned between the controller64and the anodes54and cathode56. During operation, a current can be supplied from the anode54to the cathode56via the electrolytic fluid solution52to electroform a monolithic metallic component38at the mandrel58. During supply of the current, the metal, in this example aluminum, iron, cobalt, or nickel, from the electrolytic fluid solution52forms a metallic layer70over the mandrel58.

By way of non-limiting example in an exemplary electroforming process, a pump (P) and filter (F) are utilized to filter and chemically maintain the electrolytic fluid solution52at a particular ion concentration, or to remove any foreign matter. The filter (F) can include, by way of non-limiting example, a chemical filtering media. A heater (H) is provided to regulate a temperature of the electrodeposition bath40. In non-limiting examples, the heater (H) can be disposed within the bath tank50or proximate the bath tank50exterior to the bath tank50. Alternatively, the heater (H) can be in fluid communication with the pump (P) to heat the electrolytic fluid solution52as it is pumped by the pump (P).

The temperature of the electrodeposition bath40is directly related to the level of residual internal stresses and grain size of the deposited material forming the metallic layer70and usually ranges from 50° C. to 70° C. (125° F. to 160° F.). Therefore, it can be desirable to utilize higher temperature ranges to tailor the residual internal stresses of the deposited material. However, at higher temperatures, a gradual softening of the body60of the mandrel58can occur, which can result in deformation of the structural wax or the body, which can lead to deformation of the electroformed component or uneven deposition. The softening or deflection temperature for structural wax is about 100° C. (220° F.). Therefore, even a small increase in temperature of 30° C. or more can result in deformation.

A system42including a coolant tube76, a heat exchanger78, and the mandrel58can compensate for this softening by locally cooling the body60. The coolant tube76runs through the mandrel58and through the heat exchanger78to form a cooling circuit79having a closed loop80fluidly connected to the cooling core82within the mandrel58. A coolant (Ce), or cool electrolytic fluid, relative to a bath temperature, flows through the closed loop80after being cooled by the external heat exchanger78and recirculated with a separate pump (P2). A cooling fluid (C), such as cold water, for example, is run through the heat exchanger78to cool a warm electrolytic fluid (He) after it has run through the mandrel58. The mandrel58can therefore be actively cooled during the electroforming process by the system42. After completion of the electroforming process, the body60can be reclaimed from the electroformed component, such as through heating and melting of the body60at heightened temperatures, to reclaim the structural wax material. In this way, material waste is reduced.

The coolant tube76includes exterior components77that are in contact with the electrolytic fluid solution52. Such exterior components77or other exterior surfaces should be a thermally non-conductive material, by way of non-limiting example polyvinyl chloride (PVC). Similarly, a material such as PVC is not electrically conductive and does not collect metal ions from the electrolytic fluid solution52, and no electrodeposition occurs along the coolant tube76. Therefore, a low thermal conductivity of plastic PVC can serve as a thermal insulation between a coolant (Ce) within the coolant tube76and the warmer bath40of electrolytic fluid solution52.

In one example, the coolant (Ce) in closed loop80can be a cooled electrolyte formed from the same solution as the electrolytic fluid solution52so that in the event leaking occurs from the closed loop80, the main electrodeposition bath40remains contaminate free or does not result in a decrease in overall metal ion concentration. While the closed loop80is separate from the electrodeposition bath40, a different coolant fluid type solution than that of the electrolytic fluid solution52can be considered for the coolant (Ce). However, where the goal is to remove possible cross-contamination with the bath chemistry, a coolant similar to or identical to the electrolytic fluid solution52can be utilized. More specifically, the chemical balance of the bath is critical to the electrodeposition process as well as the resulting material properties, grain size and residual stress.

FIG.2is an exemplary cross-section of a tooling die84, shown in an open position, defining a cavity86shaped to form of the metallic component38discussed inFIG.1, as the exemplary fluid carrying duct component. The tooling die84includes a tooling die top section88aand a tooling die bottom section88beach having confronting faces89a,89b. The tooling die top section88aincludes a rounded top portion87adefining the shape of the metallic component38. The tooling die bottom section88bincludes, a rectilinear bottom portion87bincluding opposite facing slanted walls for the metallic component38.

The coolant tube76can be provided between the tooling die top section88aand the tooling die bottom section88b. While illustrated as a circular tube, the coolant tube76can be any shape including oval, rectangular, or square, and is not limited by the illustration. It is further contemplated that the coolant tube76can include annular radial fins90to define at least a portion of the cooling core82. The annular radial fins90can be added to the coolant tube76to increase a cooled concentric region92via heat transfer extending from the coolant tube76.

Turning toFIG.3, the tooling die84has been closed into a closed position, with the tooling die top section88aabutting the tooling die bottom section88bat the opposing confronting faces89a,89b. The cavity86defines a wax mold cavity formed around the coolant tube76.

Referring now toFIG.4, the cavity86of the tooling die84is filled with liquid structural wax, for example, to define the body60. The liquid structural wax is cooled to form the mandrel58.

FIG.5is an isometric view of the mandrel58and the metallic component38, having the mandrel58and the metallic component38partially cut away to show the coolant tube76with exemplary annular radial fins90(both shown in dashed line). The coolant tube76forms a cooling channel94within the mandrel58that can define at least a portion of the cooling core82. While shown as only a single cooling channel94, it is contemplated that the cooling core82can include multiple cooling channels94. It is further contemplated that the coolant tube76can be used to form the cooling core82during formation of the body60, and can be removed before the electroforming process. A complex mandrel, by way of non-limiting example, with multiple bends and elbows can have a continuous segmented coolant tube76with multiple bellowed flex-joints to assist in removal. The cooling core82can further include the annular radial fins90, as discussed herein, to cool the expanded concentric region92. The annular radial fins90can provide for both increased local cooling as well as increased local structural rigidity. Finally, prior to electroforming or electro deposition, the mandrel58can be coated or treated with a metalized cathode surface, such as the metallic layer70ofFIG.1, to form a cathode surface in the electroforming process.

Turning toFIG.6, a cross-section of the mandrel58illustrates the coolant tube76passing through the mandrel58to define the cooling channel94. In one non-limiting example, the coolant tube76within the mandrel58can be a conforming tube96having threaded ends98a,98b. The conforming tube96can be formed from an inert non-consumable material, such as a titanium conduit for example. A fitting100, such as an inert non-consumable fitting, can be provided at each end102a,102bof the mandrel58to couple exterior components77of the coolant tube76to the cooling core82. In one example, electrically conductive fittings can be threaded to threadably couple and electrically connect to the exterior components77of the coolant tube76.

Referring now toFIG.7, an exemplary alternative mandrel158, according to another aspect of the disclosure is shown. The mandrel158can be substantially similar to the mandrel58ofFIG.6. Therefore, like parts will be identified with like numerals increased by a value of one hundred, with it being understood that the description of the like parts of the mandrel58applies to the mandrel158unless otherwise noted.

It is contemplated that at least a portion of a coolant tube176includes a removable portion196. The removable portion196can be removed to form a tubeless cooling core182prior to the electroforming process to form at least one cooling channel194. While shown as a single cooling channel194, it is contemplated that the tubeless cooling core182can have multiple cooling channels194. Such cooling channels194can be discrete and fluidly isolated within the mandrel158, for example. In one non-limiting example, the removable portion196of the coolant tube176can be used for complex multi-bend ducts where removal of a solid, rigid tube is not possible after completion of the electroforming or electrodeposition process. In one non-limiting example, the removable portion196can be a water-soluble wax or plastic. A fitting200can be provided at either end202a,202bof the mandrel158. The fittings200can include multiple electrically conductive o-ring seals198a,198b, such as three or more, for example, to fluidly seal and couple the exterior components177of the mandrel158to the tubeless cooling core182.

A method for producing a metallic component38with a mandrel58,158that is actively cooled during the electroforming process includes placing the mandrel58,158in an electrodeposition bath40and flowing a coolant, such as the coolant (Ce) ofFIG.1, through a cooling core82,182to actively cool the mandrel58,158during the electroforming process. The method further includes flowing the coolant (Ce) through a heat exchanger78. Actively cooling the cooling core82,182along with the concentric region92keeps the body60, formed from structural wax, at an overall temperature of below 100° C. (220° F.) and therefore resists deflection, deformation, or softening.

It is further contemplated that the method can include coating the mandrel58,158with an electrically conductive material62to form a metallic layer70. To complete the electroforming process the metallic layer70is cooled, the body60of structural wax forming the mandrel58,158can be removed leaving behind the metallic component38as discussed herein. The structural wax forming the body60can be removed using heating or a leeching process after the electroforming process. The melting temperature for structural wax is about 120° C. (250° F.). The structural wax used to form the body60can then be melted after the electroforming process at temperatures of 120° C. or greater, and reused or poured into a tooling die to form another mandrel.

As described herein, electroforming components having thin walls or electroforming components for complex thin-walled fluid delivery implementations in an aircraft engine can significantly reduce manufacturing costs and increasing quality, having greater consistency, stress-resistance, and component lifetime. Inexpensive mandrels for electroformed components can be critical to controlling costs. The use of reclaimable materials, like structural high-temperature wax, that are easily removed from closed channel electrodeposited shapes can provide for reducing cost and increasing quality. Reclaimable low-cost mandrel tooling is beneficial for the overall economic value of electroformed components. Structural wax is a material solution that is also easy to remove, thereby reducing post-processing costs.

Additionally, the process as described herein increases the thermal and dimensional stability of the wax mandrel in the hot electrodeposition bath. External loads from gravity and buoyancy can distort long and slender components of the mandrel, in addition to increased bath temperatures. Dimensional distortions of the mandrel from the gravitational and buoyance body-force loads as well as impingement velocity forces are decreased or removed with the method described herein, particularly when electroforming on a wax mandrel that is more resistant to deformation than one that is not cooled. Implementing a core that is cooled with low temperature electrolyte increases the temperature insensitivity of the wax mandrel by maintaining the structural integrity of the wax mandrel during the electroforming process. The location and impinging force of hot fluid mixing jets on long unsupported components with small cross-sectional modulus also decreases. The mandrel described herein is removable and reusable creating a cost-effective solution for creating a stable temporary mandrel form and subsequent post-process removal.

To the extent not already described, the different features and structures of the various aspects can be used in combination with each other as desired. That one feature cannot be illustrated in all of the aspects is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different aspects can be mixed and matched as desired to form new examples, whether or not the new examples are expressly described. Combinations or permutations of features described herein are covered by this disclosure. Many other possible embodiments and configurations in addition to that shown in the above figures are contemplated by the present disclosure.

This written description uses examples to describe aspects of the disclosure described herein, including the best mode, and also to enable any person skilled in the art to practice aspects of the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of aspects of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.