Abstract:
Disclosed is a method for machining a component, comprising: installing the component on a fixture, causing a medium of the fixture to solidify to encase a first portion of the component, applying a toolset to a second portion of the component that is outside of the solidified medium, and subsequent to applying the toolset, extracting the component from the fixture when the medium is in one of a liquid state or a semi-liquid state, where the medium has a melting-point temperature that is less than 500 degrees Fahrenheit. Disclosed is a fixture for machining a component, comprising: a medium configured to encase a first portion of the component when the medium is in a solidified state, and a toolset configured to be applied to a second portion of the component that is outside of the solidified medium, the medium having a melting-point temperature that is less than 500 degrees Fahrenheit.

Description:
BACKGROUND 
       [0001]    As part of an initial or maintenance-related manufacturing procedure associated with an engine, one or more components of the engine may be machined. For example, a blade of the engine may be placed in a fixture and a portion of the blade (e.g., a root, an attachment, a platform, etc.) may be machined. 
         [0002]    The fixture is typically made of a metal alloy that has a melting-point temperature that is less than a second melting-point temperature associated with the component (e.g., the blade). In terms of the machining procedure, the component is inserted in the fixture and then the metal alloy is allowed to cool to a temperature that is less than the melting-point temperature of the metal alloy such that the metal alloy solidifies and holds the component in place. Next, the technician/operator performs the machining operation on the component. Once the machining operation is complete, the fixture is heated to a temperature that is greater than the melting-point temperature of the metal alloy in order to free/release the component from the fixture. The fixture or the component may then be subject to cleaning to remove any excess material that may be present. 
         [0003]    The use of the fixture described above presents a number of challenges. It takes a considerable amount of time to apply and remove the metal alloy from the component. The metal alloy material is costly and at least some of it ends up being wasted/expended on the component; for example, some of the material may end up needing to be cleaned from the component. The use of the metal alloy, which may include lead or bismuth, may impose additional cost in terms of environmental constraints that may need to be adhered to for safe handling/operation. Accordingly, what is needed is a more cost-efficient and environmentally friendly fixture for machining engine components. 
       BRIEF SUMMARY 
       [0004]    The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosure. The summary is not an extensive overview of the disclosure. It is neither intended to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure. The following summary merely presents some concepts of the disclosure in a simplified form as a prelude to the description below. 
         [0005]    Aspects of the disclosure are directed to a method for machining a component, comprising: installing the component on a fixture, causing a medium of the fixture to solidify to encase a first portion of the component, applying a toolset to a second portion of the component that is outside of the solidified medium, and subsequent to applying the toolset, extracting the component from the fixture when the medium is in one of a liquid state or a semi-liquid state, where the medium has a melting-point temperature that is less than 500 degrees Fahrenheit. In some embodiments, the medium includes water. In some embodiments, the medium includes an injection molded material. In some embodiments, the injection molded material includes at least one of a thermoplastic, a resin, or a wax. In some embodiments, the component is a blade. In some embodiments, the first portion of the blade includes an airfoil. In some embodiments, the second portion of the blade includes at least one of a root, an attachment, or a platform. In some embodiments, the method further comprises fixing an orientation of the component in the fixture prior to applying the toolset to the component. In some embodiments, the method further comprises determining an orientation of the component in the fixture prior to applying the toolset to the component, and adapting an operation of the toolset in accordance with the determined orientation. In some embodiments, the method further comprises applying a thermal mitigation technique to at least one of the medium or the second portion of the component when the toolset is applied to the second portion of the component. In some embodiments, the method further comprises applying heat to the medium to cause the medium to transition to the one of a liquid state or a semi-liquid state. 
         [0006]    Aspects of the disclosure are directed to a fixture for machining a component, comprising: a medium configured to encase a first portion of the component when the medium is in a solidified state, and a toolset configured to be applied to a second portion of the component that is outside of the solidified medium, where the medium has a melting-point temperature that is less than 500 degrees Fahrenheit. In some embodiments, the fixture further comprises gage pins configured to fix an orientation of the component. In some embodiments, the fixture further comprises a scanning device configured to scan the component and generate data that pertains to an orientation of the component in the fixture, and a control computer configured to process the data to determine the orientation and control the toolset in accordance with the determined orientation. In some embodiments, the scanning device is operative on the basis of white light or the use of a laser. In some embodiments, the fixture further comprises a cooling source configured to cool the medium when the toolset is applied to the second portion of the component. In some embodiments, the cooling source includes a source of liquid nitrogen. In some embodiments, the fixture further comprises a control computer, and a temperature sensor, where the cooling source is controlled by the control computer based on an output of the temperature sensor. In some embodiments, the fixture further comprises a heat sink coupled to the second portion. In some embodiments, the fixture further comprises a control computer, a temperature sensor, and a thermal pad with resistive heaters that are controlled by the control computer based on an output of the temperature sensor that cause the medium to transition from the solidified state to at least one of a liquid state or a semi-liquid state. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements. The drawings are not necessarily drawn to scale unless specifically indicated otherwise. 
           [0008]      FIG. 1  is a side cutaway illustration of a geared turbine engine. 
           [0009]      FIG. 2  illustrates a system that includes a component incorporated as part of a fixture in accordance with aspects of the disclosure. 
           [0010]      FIG. 3  illustrates a flowchart of an exemplary method in accordance with aspects of this disclosure. 
           [0011]      FIG. 4  illustrates a computing system in accordance with aspects of this disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. 
         [0013]    In accordance with aspects of the disclosure, apparatuses, systems, and methods are directed to a fixture for machining a component. The component may be incorporated as part of an engine. In some embodiments, the component may include a blade (e.g., a fan blade, a compressor blade, a turbine blade, etc.). The fixture may include a medium that may undergo a phase change for fixing/securing the component prior to a machining operation and releasing the component following the machining operation. In some embodiments, the medium may include water or an injection molded material. 
         [0014]    Aspects of the disclosure may be applied in connection with a gas turbine engine.  FIG. 1  is a side cutaway illustration of a geared turbine engine  10 . This turbine engine  10  extends along an axial centerline  12  between an upstream airflow inlet  14  and a downstream airflow exhaust  16 . The turbine engine  10  includes a fan section  18 , a compressor section  19 , a combustor section  20  and a turbine section  21 . The compressor section  19  includes a low pressure compressor (LPC) section  19 A and a high pressure compressor (HPC) section  19 B. The turbine section  21  includes a high pressure turbine (HPT) section  21 A and a low pressure turbine (LPT) section  21 B. 
         [0015]    The engine sections  18 - 21  are arranged sequentially along the centerline  12  within an engine housing  22 . Each of the engine sections  18 - 19 B,  21 A and  21 B includes a respective rotor  24 - 28 . Each of these rotors  24 - 28  includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed, adhered and/or otherwise attached to the respective rotor disk(s). 
         [0016]    The fan rotor  24  is connected to a gear train  30 , for example, through a fan shaft  32 . The gear train  30  and the LPC rotor  25  are connected to and driven by the LPT rotor  28  through a low speed shaft  33 . The HPC rotor  26  is connected to and driven by the HPT rotor  27  through a high speed shaft  34 . The shafts  32 - 34  are rotatably supported by a plurality of bearings  36 ; e.g., rolling element and/or thrust bearings. Each of these bearings  36  is connected to the engine housing  22  by at least one stationary structure such as, for example, an annular support strut. 
         [0017]    During operation, air enters the turbine engine  10  through the airflow inlet  14 , and is directed through the fan section  18  and into a core gas path  38  and a bypass gas path  40 . The air within the core gas path  38  may be referred to as “core air”. The air within the bypass gas path  40  may be referred to as “bypass air”. The core air is directed through the engine sections  19 - 21 , and exits the turbine engine  10  through the airflow exhaust  16  to provide forward engine thrust. Within the combustor section  20 , fuel is injected into a combustion chamber  42  and mixed with compressed core air. This fuel-core air mixture is ignited to power the turbine engine  10 . The bypass air is directed through the bypass gas path  40  and out of the turbine engine  10  through a bypass nozzle  44  to provide additional forward engine thrust. This additional forward engine thrust may account for a majority (e.g., more than 70 percent) of total engine thrust. Alternatively, at least some of the bypass air may be directed out of the turbine engine  10  through a thrust reverser to provide reverse engine thrust. 
         [0018]      FIG. 1  represents one possible configuration for an engine  10 . Aspects of the disclosure may be applied in connection with other environments, including additional configurations for gas turbine engines. Aspects of the disclosure may be applied in connection with non-geared engines. 
         [0019]    Referring to  FIG. 2 , a system environment  200  is shown. At least a portion of the system  200  may be associated with a fixture as described below. 
         [0020]    The system  200  is shown as including a blade  202  having an airfoil  206 . In some applications, the blade  202  may be produced via a casting process. At least a portion of the blade  202 , denoted by reference character  210 , may be subject to machining. Examples include where the blade  202  is cast, with the airfoil  206  portion of the blade  202  formed with predefined geometric characteristics but other portions of the blade  202  require more precise dimensional characteristics and surface finish than a coating process can efficiently generate. In such embodiments, the portion  210  may correspond to a root, an attachment, or a platform of the blade  202  used to precisely position the blade  202  relative to adjacent components. 
         [0021]    The blade  202  may be located within a medium  214  of a fixture. In some embodiments, the medium  214  may include water that may have an associated melting-point temperature of approximately 32 degrees Fahrenheit (approximately 0 degrees Celsius). In some embodiments, the medium  214  may include an injection molded material, such as for example a thermoplastic, a resin, a wax, etc. In some embodiments, the medium  214  may include nylon or other polymer materials. The injection molded material may have a melting-point temperature within one or more temperatures ranges, such as for example a range of 200 degrees Fahrenheit (approximately 93 degrees Celsius) and 500 degrees Fahrenheit (approximately 260 degrees Celsius). The use of an injection molded material for the medium  214  may allow the medium to tolerate higher loads than if water alone is used as the injection molded material may impart greater strength. Conversely, material removal machining techniques, including super abrasive machining, may be selected in order to minimize the induced loading on the fixture airfoil in an effort to more closely match the capability of the fixture. The medium  214  may be applied using one or more sources, such as for example the medium source  216 . 
         [0022]    The fixture may include one or more gage pins  220 . The pins  220  may be used to create a reference datum for locating the blade  202  within the fixture (e.g., the medium  214 ). The pins  220  may provide information regarding the orientation of the blade  202  in one or more spatial dimensions. The pins  220  may assist in providing a predetermined orientation to the blade  202  such that a toolset  230  associated with the machining operation may be fixed. Stated slightly differently, the pins  220  may ensure a particular orientation of the blade  202  in the fixture, such that the machining operation performed using the toolset  230  may be repeated for each instance of a blade  202  installed on the fixture. 
         [0023]    In some embodiments, a scanning device  240  may be configured to scan the blade  202  when the blade  202  is installed on the fixture. The scanning device  240  may be operative on the basis of white light or the use of a laser. The scanning device  240  may respond to commands issued by a control computer  250  to scan the blade  202 . Data acquired by the scanning device  240  (where the data may be based on absorption, reflection, diffraction, or other characteristics) may be provided to the control computer  250 . The control computer  250  may process the data to determine an orientation of the blade  202  in the fixture. This determined orientation may be used by the control computer  250  to establish a set of control parameters that may be used to control the toolset  230 . For example, the control computer  250  may establish the control parameters and control the toolset  230  in accordance therewith. Thus, the use of the scanning device  240  and/or the control computer  250  may represent an alternative to the use of pins  220 . The use of the scanning device  240  and the control computer  250  may allow for an adaptation of the toolset  230  based on variations in the orientation of the blade  202  within the fixture. 
         [0024]    As the toolset  230  is applied as part of the machining operation, the portion  210  of the blade  202  that is subject to the machining may tend to get hot based on imparted frictional loads form the machining process. In order to maintain the medium  214  in a sufficiently solidified state, one or more sources  260  may be enabled/activated as part of a loop formed with, e.g., the medium  214 , to cool the medium  214 . In some embodiments, the source  260  may include liquid nitrogen. The source  260  (or associated loop) may be enabled or disabled by the control computer  250 . The determination of whether to enable or disable the source  260  may be based on the output of one or more sensors  270  coupled to the control computer  250 . The sensors  270  may include one or more temperature sensors. The sensors  270  may be in contact with the blade  202  encased in the medium  214  to monitor heat transfer during machining. 
         [0025]    In some embodiments, a coolant collar/heat sink  280  may be applied to the portion  210  in proximity to the interface between the portion  210  and the toolset  230 . The heat sink  280  may deter or prevent a conductive heat transfer into the medium  214 . 
         [0026]    Once the machining operation is complete, any cooling that may have been provided by the source  260  or the heat sink  280  may be removed/disabled. If the melting-point of the medium  214  is less than, e.g., room temperature the medium may be allowed to sit/rest until the melting-point temperature is reached at which point the blade  202  may be extracted/removed from the fixture. Alternatively, if the melting-point temperature of the medium  214  is greater than room temperature or if there is a desire to accelerate the extraction of the blade  202  from the fixture, a source of heat may be applied to the medium  214 . The source of heat may correspond to the source  260  (e.g., the same source  260  may be used to cool or heat the medium  214 ) or a separate, dedicated source. The source of heat may be operative on the basis of a thermal pad with resistive heaters that is applied to the medium  214 . The source of heat may be controlled by the control computer  250 ; the control computer  250  may provide such control based on the output(s) of the sensor(s)  270 . 
         [0027]    Referring now to  FIG. 3 , a flowchart of an exemplary method  300  is shown. The method  300  may be used to machine a component (e.g., the blade  202 ) using a toolset (e.g., toolset  230 ) via a fixture. 
         [0028]    In block  306 , the component may be installed on the fixture. As part of the installation, a medium (e.g., medium  214 ) of the fixture may be maintained in a liquid or semi-liquid state. 
         [0029]    In block  312 , the orientation of the component may be fixed (e.g., by the pins  220 ) and/or determined (e.g., via the scanning device  240  and the control computer  250 ). 
         [0030]    In block  318 , the medium may solidify to encase a portion of the component (e.g., the airfoil  206 ). As part of block  318 , one or more cooling sources (e.g., source  260 ) or associated coolant loops may be enabled/activated to facilitate the solidification of the medium. 
         [0031]    In block  324 , a toolset (e.g., toolset  230 ) may be applied to at least a portion of the component (e.g., portion  210 ) to machine the component. To the extent that the orientation of the component in the fixture is variable, the operation of the toolset may be adapted based on the orientation determined as part of block  312 . 
         [0032]    In block  330 , one or more thermal mitigation techniques may be applied. For example, a heat sink (e.g., heat sink  280 ) may be installed on the component (e.g., the portion  210 ) and/or a cooling source or associated coolant loop may be enabled/activated. 
         [0033]    In block  336 , the machining may be completed. As part of block  336 , any thermal mitigation techniques that may have been applied (e.g., as part of block  330 ) may be removed. 
         [0034]    In block  342 , the medium may be allowed to transition from a solid to a liquid or semi-liquid state in order to allow the component to be extracted from the fixture. One or more sources of heat may be applied to the medium as part of block  342  to accelerate the extraction of the component. 
         [0035]    The blocks/operations associated with the method  300  are illustrative. In some embodiments, the blocks may execute in an order or sequence that is different from what is shown in  FIG. 3 . In some embodiments, one or more of the blocks (or a portion thereof) may be optional. 
         [0036]    Referring now to  FIG. 4 , an illustrative system  400  is shown. The system  400  may be associated with one or more computers and/or one or more controllers (e.g., the control computer  250  of  FIG. 2 ). 
         [0037]    The system  400  includes one or more processors (generally shown by a processor  402 ) and a memory  404 . The memory  404  may store data  406  and/or instructions  408 . The system  400  may include a computer-readable medium (CRM)  410  that may store some or all of the instructions  408 . The CRM  410  may include a transitory and/or a non-transitory computer-readable medium. 
         [0038]    The instructions  408 , when executed by the processor  402 , may cause the system  400  (or one or more portions thereof) to perform one or more methodological acts or processes, such as those described herein. 
         [0039]    The data  406  may include data obtained from one or more entities (e.g., the scanning device  240 , the sensor  270 ). The data  406  may include results of processing the obtained data. For example, the data  406  may include a specification of an orientation of a component (e.g., blade  202  of  FIG. 2 ) within a fixture, where the specified orientation may map to parameters that may be used to control a machining operation or a toolset (e.g., toolset  230 ). 
         [0040]    In some embodiments, the data  406  may be associated with one or more programs, such as a modeling or simulation program. For example, the data may be native to or supported by one or more computed aided design or computer aided drawing programs, either one or both of which may be referred to as CAD programs. The data  406  may be used in connection with aligning a component and tooling. 
         [0041]    The system  400  may include one or more input/output (I/O) devices  412  that may be used to provide an interface between the system  400  and one or more additional systems or components. The I/O devices  412  may include one or more of a graphical user interface (GUI), a display screen, a touchscreen, a keyboard, a mouse, a joystick, a pushbutton, a microphone, a speaker, a transceiver, a sensor, etc. 
         [0042]    Technical effects and benefits of this disclosure include machining operations facilitated by a fixture that is easier and cheaper to operate while also being more environmentally friendly/accommodating. Cycle times for machining components are reduced while providing a constant clamping load to resist vibration during machining. The use of a low melting-point medium reduces energy costs, lessens operator/technician exposure to elevated temperatures, and opens up additional, lower melting-points that may be used with the components being machined. To the extent that water is used as the fixture medium, there is no appreciable chemical interaction between the medium and the component being machined and any residual water that may be on the component following the extraction of the component from the fixture will evaporate, thereby reducing any cleaning operations. Use of water as a medium also enables incorporation of other components (composite, injection molded thermoplastic, etc.) as part of a fixture, where those other components might not be thermally compatible with conventional low-melt alloy processes. 
         [0043]    Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure. One or more features described in connection with a first embodiment may be combined with one or more features of one or more additional embodiments.