The present invention generally relates to the manufacture and repair of turbomachine products, and more particularly relates to creating preforms for use in turbomachine products.
In rotary equipment such as fans, compressors and turbines of turbomachines, field operation may result in degradation of component parts. An existing option to discarding and replacing a worn part with a newly manufactured item, is to repair and recondition the part for reuse. The ability to successfully repair parts is subject to a number of limitations. For example, the geometry of the area of the part requiring repair may be overly complex to undertake conventional repair approaches. Other limitations may arise. For example, such as with increasingly tight tolerances, returning a field run part to original specifications may not be practical.
Various types of articles may be created using additive manufacturing processes. Additive manufacture includes processes such as those that create a component or item by the successive addition of particles, layers or other groupings of a material onto one another. The article is generally built using a computer controlled machine based on a digital representation, and includes processes such as 3-D printing. A variety of different additive manufacturing processes are used for part creation, such as processes that involve powder bed fusion, laser metal deposition, material jetting, or other methods.
It is desirable to repair and reuse turbomachine parts, including those with parts having a complex geometry, by returning the parts to within original specifications in an efficient and effective manner. In addition, it is desirable to apply economical and flexible processing techniques, such as those employing additive manufacturing technologies, where doing so is efficient and effective. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
This summary is provided to describe select concepts in a simplified form that are further described in the Detailed Description section hereof. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
A number of embodiments include a method of modifying a section of a product. A preform is formed to fit the section. The preform matches preferred dimensions of the section, to achieve an extent of modification of the section required based on the section's determined state. A base material is selected with properties desired for the modification of the section. A binder is selected that vaporizes at a temperature below a melting point of the base material. The preform is built by the selective application of the binder to the base material to achieve design dimensions of the section when the preform is joined to the section. Before or after forming the preform, the section is prepared for effecting the extent of modification. The preform is positioned on the section and the two are heated at the temperature to substantially eliminate the binder from the preform and to maintain the preform below the melting point of the base material. After substantially eliminating the binder from the preform, the section and the preform are thermally processed at an elevated temperature to at least partially melt the base material to harden the preform and to bond the preform to the section.
Other embodiments include a method of modifying a section of a product including forming a preform set to fit the section. The preform set includes one or more preforms that match preferred dimensions of the section, so that when the preform is added to the section the preform achieves an extent of modification of the section required based on a determined state of the section. Forming the preform(s) includes selecting a base material with properties desired for the modification of the section. A binder is selected that vaporizes at a temperature below a melting point of the base material. The preform(s) is/are built by binder jetting additive manufacturing by the selective application of the binder to the base material layer-by-layer to achieve design dimensions of the section when the preform is joined to the section. Before or after forming the preform(s), the section is assessed to ascertain the determined state. Before or after assessing the section, the section is prepared in readiness for effecting the extent of modification. A preform is selected from the preform set to match the extent of modification needed based on the determined state, and is positioned on the section. After positioning the preform on the section, the section and the preform are heated at the temperature to substantially eliminate the binder from the preform and to maintain the preform below the melting point of the base material. After substantially eliminating the binder from the preform, the section and the preform are thermally processed at an elevated temperature to at least partially melt the base material to harden the preform and to bond the preform to the section.
In additional embodiments, a method of modifying a section of a turbomachine product includes forming a preform set to fit the section. The preform set includes one or more preforms that match preferred dimensions of the section so that when a selected preform is added to the section, the preform achieves an extent of modification required based on a determined state of the section. Forming the preform includes selecting a base material with properties desired for the modification of the section and selecting a binder that vaporizes at a temperature below a melting point of the base material. The preform(s) is/are built by binder jetting additive manufacturing by the selective application of the binder to the base material to achieve design dimensions of the section when the preform is joined to the section. The section is assessed to ascertain the determined state. The section is prepared for effecting the extent of modification, including one or more of cleaning, material removal, material addition, material shaping and forming. A preform is selected that matches the extent of modification needed based on the determined state, and the preform is positioned on the section. After positioning the preform on the section, the section and the preform are heated at the temperature to substantially eliminate the binder from the preform and to maintain the preform below a melting point of the base material. After substantially eliminating the binder from the preform, the section and the preform are thermally processed at an elevated temperature to at least partially melt and flow the base material to harden the preform and to bond the preform to the section.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Thus, any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described herein are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary, or the following detailed description.
In the current description, additive manufacturing techniques such as binder jetting may be used to achieve customized preforms for repair and/or for original manufacture of products, such as turbomachinery. In addition, features such as inserts, add-ons, protective layers and others may be created by using an additive manufacturing process such as binder jetting to extend the operational capabilities and/or life of a turbomachine system. The methods and processes disclosed herein may enable the manufacture of complex geometry and/or other performance optimizing characteristics that have been impractical prior to these developments. Repair and manufacturing techniques are disclosed herein to return parts to original specifications and/or to manufacture new parts with features that provide beneficial performance capabilities. Additive manufacturing is herein employed as an enabler for repairing/creating these complex parts, which otherwise may be prohibitively difficult or costly to repair and/or manufacture. In the examples given herein, details may be associated with a specific component and/or machine type, but the disclosure is not limited in application to any specific component or to any particular type of machine, but rather may be applied to any component, machine or assembly where improved repair options or extended performance is desired. In addition, the disclosure is not limited to any specific additive manufacturing technology.
In embodiments of the present disclosure as further described below, structural/geometry repair and methods of manufacturing relate to modifying a section of a product such as a turbomachine or one of its component parts. In general, methods may include creating a preform or a number of preforms to fit the section, where the preform(s) match preferred dimensions of the section to achieve an extent of modification required based on a determined state of the section.
In one embodiment, a preform may be created as needed based on the state of a field-run product and the extent of repair needed. In an additional embodiment, a set of preforms with a range of geometric magnitudes, materials or other varying characteristics may be created in advance to fit a product, and one preform within the set may be selected based on the extent of repair needed. In another embodiment, a preform may be created, such as with a complex geometry or other difficult to manufacture characteristic, for assembly into a new, original manufactured product. As used herein, references to a “set of preforms,” may be references to one single preform and/or to any plural number of preforms applicable for the context.
In general, modifying a section of a product may include forming a set of preforms from a base material and a binder, such as by binder jet additive manufacturing. In coordination, the section may be prepared for effecting the extent of modification needed, and an assessment may be made to determine the section's state. A preform is created or selected to match the extent of modification needed based on creating or returning the section to the design state of the product from the determined state of the product. The preform, in green condition, is positioned on the section and then the combination is heated and thermally processed with the preform in-situ on the section. The preform and section are heated at the temperature to substantially eliminate the binder from the preform, while maintaining the preform below the melting point of the base material. After substantially eliminating the binder from the preform, the section and the preform are thermally processed at an elevated temperature to at least partially melt the base material to harden the preform and to bond the preform to the section of the product. Processing the preform in-situ on the section provides efficiency and economy, including by obviating the need for pre-sintering.
Referring to
More specifically, in many types of additive manufacture, the range of feedstock material is often limited by the ability to weld the material. When applying a heat source, materials commonly used in hot section turbomachine components (combustors, turbines) may experience strain age cracking or solidification cracking. Since binder jetting, for example, does not melt the base material 24, complex shapes may be fabricated without undesirable outcomes that could be observed in additive manufacturing processes that involve fusion of molten material. The base material 24 may be a braze alloy such as a mixture of one or more metal alloys and may include a melting point suppressant, such as boron. Avoiding the use of a heat source to create a structure from a braze alloy type base material 24, avoids outcomes such as keyhole porosity, distortion, and others.
Using the manufacturing system 20 without a heat source such as in binder jetting enables the manufacture of products as braze alloy pre-formed shapes. Creating such products may be used to repair fielded hardware and may be used in creating newly manufactured original equipment hardware. Braze alloys may be used to create products such as the preform 22 and to make repairs such as healing cracks and to repair dents, nicks and erosion, including on airfoils. Braze alloys may be used in the manufacturing system 20 to create preforms 22 to dimensionally restore or build up surfaces, such as to achieve a specific effective flow area in stators and nozzles. The manufacturing system 20 enables the manufacture of intricate details (such as cooling holes) extending the ability to create new products and to repair items such as cooled nozzles without masking cooling holes.
In the embodiment of
The build platform 30 is configured for repositioning at various heights within the build chamber box 26 during a build process. An actuator 48, such as a cylinder, is coupled with the build platform 30 to effect vertical movement. Another actuator 50 is coupled with a piston 52 to move the base material 24 within the reservoir 34 for pickup by the spreader 38. Inside the build chamber box 26, the base material 24 is spread into the build area 28 on the build platform 30 one layer at a time. The print head 46 is selectively directed over individual layers of the deposited base material 24 and applies the binder 42 to areas as necessary to define a segment of the preform 22 from an applied layer. The build platform 30 is then lowered by the depth of one layer. Additional binder 42 is applied to that layer and the process is repeated for successive layers until the preform 22 is completely defined in green form, with the binder 42 adhering the base material 24 together. At this stage, the base material 24 is not fused together and the green preform 22 has a homogenous composition with no heat induced distortion or effects. The binder 42 may be a liquid binding agent and the base material 24 may be a braze alloy in powder form. In some embodiments, a relatively low temperature heat may be applied to accelerate adhesion, but without melting the braze alloy. In green form, the preform 22 may have dimensions that accommodate changes in further processing such as shrinkage due to elimination of the binder 42 or other changes such as due to heating of the base material 24.
Referring to
Processing the preform 22 and the section 56 mated together in a heated environment is depicted in
Depicted in
As shown schematically in
A thin preform 80 as a protective coating is illustrated schematically in
Referring to
The process 100 includes selecting 102 materials for a set of preforms 22, 72, 74, 80. The selecting 102 may include selecting a base material 24 with properties desired for the modification of the section 56, 82. The “base material,” is a material selected for the preform 22, 72, 74, 80, which may be a material that is substantially similar in composition to a material from which the product is made, or a material that provides desirable characteristics to enhance the product. In the case of brazing, the base material 24 may be selected to have a lower melting point than the adjoining metal of the section 56, 82. In an embodiment, a braze alloy such as MARM247 alloy or another alloy may be used. In another embodiment, the base material may be a material that has improved corrosion-resistance, oxidation-resistance, thermal performance, or other desired properties. Other specific material examples may be found in U.S. Pat. No. 7,824,510 issued Nov. 2, 2010, which is commonly assigned and which is specifically incorporated herein by reference. In a number of embodiments, the set of preforms may be created from different materials having different performance characteristics from which a selection may be made for joining with the section 56, 82 depending on the desired outcomes for the application.
As part of the selecting materials 102, the binder 42 is selected, where the binder 42 vaporizes at a temperature below a melting point of the base material 24. In an embodiment, the temperature may be in the range of 800-900 degrees Celsius. The specific binder 42 material may be a synthetic or natural binding substance, such as a wax based substance, and in practice may be any material that delivers the requisite binding action and that is compatible with the base material 24. The base material 24 and the binder 42 may be provided in a powder, liquid or another form appropriate for delivery. In an embodiment, a liquid binding agent is applied onto a thin deposited layer of powder base material particles to build the preform set 22, 72, 74, 80. Building is accomplished by the selective application of the binder 42 to the base material 24 layer-by-layer, to achieve the design dimensions of the section 56, 82 of the product when a preform is mated with a section and thermally processed. In an embodiment, the proportion of binder 42 to base material 24 in the preform 22, 72, 74, 80 may be approximately ten-percent by-weight of binder 42 or less. Maintaining a relatively low proportion of binder 42 minimizing shrinkage, while providing sufficient adhesion for mating with the section 56, 82 during handling, heating and thermally processing.
The process 100 includes preparation 104 of the section 56, 82 of the product for effecting the extent of modification desired and/or for matching a prefabricated preform 22, 72, 74, 80. Preparation 104 of the section 56, 82 may include one or more of cleaning, material removal, material addition, shaping, forming the section, and/or other operations that prepare the section 56, 82 for receiving a preform 22, 72, 74, 80. In a number of embodiments, the preparation 104 may include original creation of the section with a void to be filled by a preform. When modifying an originally manufactured product, the section 56, 82 is prepared to receive a preform 22, 72, 74, 80 so that the combination results in the intended design state. When repairing a field-run part, the section 56, 82 may be assessed 106 to ascertain its determined state and the extent of modification needed. The determined state is the condition of the product and the assessment includes determining whether the section 56, 82 is repairable, the types of repairs required, and the geometry of any required preforms to accomplish the repair. When a prefabricated set of preforms 22, 72, 74, 80 is available, the assessment includes determining which one of the set will best fit the needed repair.
Forming 108 the preform set 22, 72, 74, 80, may include forming 108 following the assessment 106 to fit the state of modification needed. In other embodiments, forming may include forming 108 in advance to provide a range of alternative preforms 22, 72, 74, 80 in a set so that one may be selected from the set based on the assessment 106. Selecting 110 from the preform set 22, 72, 74, 80 enables matching to the extent of modification needed based on a design state or on a determined state of the section 56, 82.
In a number of embodiments, the steps of preparation 104, assessment 106, forming 108, and selection 110 are carried out in coordination and in any number of orders. For example, the preparation 104 may be carried out to an extent so that when a prefabricated preform 22, 72, 74, 80 is placed in location on the section 56, 82, the end result will return the section 56, 82 to design specifications. In other embodiments, preselecting, such as from a set, which specific preform 22, 72, 74, 80 will be used assists in the determining the extent of preparation 104 needed. For example, material may be removed so that a specific existing preform will fit. In another example, where the preform 22, 72, 74, 80 is tailor made based on the determined extent of modification needed as discerned from the assessment, 106, the preparation 104 may be more limited.
Forming 108 may be carried out using the manufacturing system 20. Three-dimensional math data may be created based on the design of the section 56, 82 or based on the assessment 106. The data may be used to program the manufacturing system 20 to produce the set of preforms 22, 72, 74, 80. The manufacturing system 20 builds the preforms 22, 72, 74, 80 by depositing, via the material deposition system 32 individual layers of the base material 24 in the build area 28. Following the deposition of each layer of the base material 24, the jetting system 40 applies the binder 42 to select areas to define the green preform 22, 72, 74, 80. Employing binder jetting enables dialing in the precise amount of base material 24 needed so that excess removal is minimized following joining with the section 56, 82. When the preform 22, 72, 74, 80 is completely formed and any time for curing is run, excess base material 24 may be vacuumed or otherwise removed from the build area 28 and the preform 22, 72, 74, 80 is also removed. The preform 22, 72, 74, 80 is in a green state at this point with the binder 42 holding the base material 24 together. In some embodiments, the preform 22, 72, 74, 80 may be subjected to relatively low heat to speed curing, without driving the binder 42 out of the base material 24.
Continuing with the process 100, the preform 22, 72, 74, 80, in green condition, is positioned 112 to mate with the section 56, 82. The section 56, 82 and the preform 22, 72, 74, 80 are placed 114 in the enclosure 62. In embodiments, the section is placed 114 in a position so that the preform 22, 72, 74, 80 remains in its intended location. In other embodiments, a fixture, clamp, tape, adhesive, or other mechanism (not shown), may be used to hold the preform 22, 72, 74, 80 and the section 56, 82 together during further processing.
The section 56, 82, with the mating preform 22, 72, 74, 80 in place, is heated 116 by being subjected to an elevated temperature to eliminate the binder 42 from the base material 24, without melting or flowing the base material 24. The temperature may be in the range of 800-900 degrees Celsius, or otherwise depending on the composition of the binder 42 and the flow temperature of the base material 24. Following elimination of the binder 42, the section 56, 82 with mating preform 22, 72, 74, 80 may be transferred to a different heat treatment enclosure or may be thermally processed again in the same enclosure 62.
Following elimination of the binder 42, the preform 22, 72, 74, 80 and section 56, 82 structure is thermally processed 118 to consolidate the preform in a solid form and to join it with the section 56, 82. For example, diffusion bonding, brazing, or any other suitable consolidation/joining process may be used for the materials employed. The thermal processing 118 is conducted at higher temperatures than the heating 116. In an embodiment, the thermal processing 118 may be carried out above 1000 degrees Celsius, such as over 1200 degrees Celsius to flow the base material 24. The joining may include forming a metallurgical bond between the preform 22, 72, 74, 80 and the section 56, 82. Following the thermal processing 118, any post joining processes that are needed for the application may be carried out and the section 56, 82 is ready for use.
Through the embodiments disclosed herein binder jet additive manufacturing technology may be used to manufacture braze alloy preforms. The preforms fabricated by binder jetting expand the ability to repair field-run hardware and enable the manufacture of intricate details that otherwise would be impractical. Employing binder jetting enables dialing in the precise amount of braze alloy needed so that excess removal is minimized following brazing. While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.