Patent Publication Number: US-2016221122-A1

Title: Hybrid additive manufacturing method for rotor

Description:
BACKGROUND 
     The subject matter disclosed herein generally relates to turbomachinery rotors, and more specifically, hybrid additive manufacturing methods for fabricating turbomachinery rotors. 
     Current manufacturing technologies may limit the optimization of aerodynamic surfaces on components such as fan rotors used in aircraft systems. Known fan rotors are formed using traditional subtractive manufacturing to remove material from a block of metal such as aluminum or titanium. For example, the block of metal may be machined to produce the finished fan rotor. However, unused material is often discarded, costs are not recuperated, and the machining process may be expensive and time consuming. 
     BRIEF SUMMARY 
     In one aspect, a method of manufacturing a rotor having a hub and a plurality of vanes extending therefrom is provided. The method includes providing the hub, the hub having an outer surface, and depositing a laser cladding on the hub outer surface to form the plurality of vanes. 
     In addition to one or more of the features described above, or as an alternative, further embodiments include: wherein the step of providing the hub comprises providing a block of material from which the hub will be formed, and machining the block of material to form the hub; wherein the step of depositing a laser cladding comprises depositing a first layer of laser cladding on the hub outer surface, subsequently machining the first layer, depositing a second layer of laser cladding on the machined first layer, and subsequently machining the second layer to form a first vane of the plurality of vanes on the hub outer surface; wherein the step of depositing a laser cladding comprises depositing a first layer of laser cladding on a first location of the hub outer surface, subsequently machining the first layer and depositing a second layer of laser cladding on a second location of the hub outer surface, subsequently machining the second layer and depositing a third layer of laser cladding on the machined first layer, subsequently machining the third layer of laser cladding to form a first vane of the plurality of vanes on the hub outer surface, and depositing a fourth layer of laser cladding on the machined second layer, and subsequently machining the fourth layer of laser cladding to form a second vane of the plurality of vanes on the hub outer surface; rotating the hub between the steps of depositing a first layer of laser cladding on a first location of the hub outer surface and subsequently machining the first layer and depositing a second layer of laser cladding on a second location of the hub outer surface; wherein the step of rotating the hub includes rotating the hub approximately 180°; and/or forming the first vane and the second vane on diametrically opposite sides of the hub. 
     In another aspect, a workstation for fabricating a rotor having a hub and a plurality of vanes extending therefrom is provided. The workstation includes a workpiece platform configured to hold the hub, a laser cladding device configured to deposit a laser cladding on the hub, and a vane machining device configured to machine the deposited laser cladding to form one or more vanes of the plurality of vanes. 
     In addition to one or more of the features described above, or as an alternative, further embodiments include: a hub machining device configured to machine a workpiece to form the hub; a measuring device configured to measure at least one of the hub and the plurality of vanes; a controller in signal communication with the workpiece platform, the laser cladding device, and the vane machining device, the controller programmed to deposit, with the laser cladding device, a first layer of laser cladding on the hub outer surface, subsequently machine the first layer with the vane machining device, deposit a second layer of laser cladding on the machined first layer, and subsequently machine the second layer to form a first vane of the plurality of vanes on the hub outer surface; a controller in signal communication with the workpiece platform, the laser cladding device, and the vane machining device, the controller programmed to deposit, with the laser cladding device, a first layer of laser cladding on a first location of the hub outer surface, subsequently machine the first layer with the vane machining device, and deposit a second layer of laser cladding on a second location of the hub outer surface, subsequently machine the second layer and deposit a third layer of laser cladding on the machined first layer, subsequently machine the third layer of laser cladding to form a first vane of the plurality of vanes on the hub outer surface, and deposit a fourth layer of laser cladding on the machined second layer, and subsequently machine the fourth layer of laser cladding to form a second vane of the plurality of vanes on the hub outer surface; wherein the controller is further programmed to rotate the hub between the steps of depositing a first layer of laser cladding on a first location of the hub outer surface and subsequently machining the first layer and depositing a second layer of laser cladding on a second location of the hub outer surface; and/or wherein rotating the hub comprises rotating the hub approximately 180°. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a perspective view of an exemplary completed fan rotor manufactured according to a hybrid additive manufacturing process; 
         FIG. 2  is a perspective view of a fan rotor hub of the completed fan rotor shown in  FIG. 1 ; 
         FIG. 3  is a perspective view of a partially completed fan rotor; 
         FIG. 4  is a perspective view of a partially completed fan rotor; 
         FIG. 5  is a schematic view of an exemplary workstation for manufacturing the fan rotor shown in  FIG. 1 ; and 
         FIG. 6  is a flow diagram of an exemplary method of manufacturing the fan rotor shown in  FIG. 1 . 
     
    
    
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exemplary turbomachinery rotor  10  fabricated by a hybrid additive manufacturing process, as described herein in more detail. In one embodiment, rotor  10  may be a fan rotor  10 . However, turbomachinery rotor  10  may be fabricated for various other components such as compressors, turbines, or the like. In the illustrated embodiment, rotor  10  is a fan rotor  10  having a hub  12  and a plurality of blades or vanes  14 . 
     As shown in  FIGS. 1-4 , hub  12  includes an outer diameter surface  16  from which vanes  14  radially extend. Hub  12  is fabricated from a metal material by traditional machining, casting, forging, or other known manufacturing process. 
     Vanes  14  are subsequently added to or formed on outer diameter surface  16  by additive manufacturing such as laser cladding material onto hub  12  with material feed wire or powder. Laser cladding by metal injection includes a laser  18  ( FIG. 5 ) directing a laser beam down a passage in focused alignment with a flow of powdered metal (or feed wire), typically in a conical flow around the laser. Laser  18  melts both a thin layer of hub outer surface  16  and the metal powder/wire introduced to surface  16 , allowing the molten powder/wire metal to fuse with outer surface  16  to form a first layer  20  ( FIG. 3 ). Layers  20  of various thicknesses can be formed on hub  12  using laser cladding. For example, a layer  20  may be in a range of between 0.25 and 0.75 inches in a single pass. Multiple layers  20  may be formed on top of each other to form each vane  14  (see  FIG. 4 ). Moreover, one layer  20  may comprise a plurality of sub-layers (not shown) formed using laser cladding. 
     During formation of vane  14 , the metal deposition material builds-up on hub  12  to form an oversized vane  14  that is bonded to hub  12  at outer surface  16 . The oversized vane  14  is larger than a desired vane size, and the oversized vane  14  is subsequently machined to the desired dimensions. In one example, the subsequent machining includes grinding, grit blasting, polishing, or other known machining methods to provide a smooth surface. Accordingly, the hybrid additive manufacturing process includes machining hub  12 , forming a plurality of vanes  14  on hub  12  via a laser cladding process, and machining vanes  14  to a desired shape and size. 
       FIG. 5  is a schematic view of an exemplary workstation  100  for carrying out the hybrid additive manufacturing process. Workstation  100  generally includes a workpiece platform  102 , one or more hub machining devices  104 , one or more laser cladding devices  106 , one or more vane machining devices  108 , and a measuring device  110 . 
     Workpiece platform  102  is configured to secure or hold hub  12  during the manufacture of fan rotor  10 . Workpiece platform  102  may be configured to spin or rotate hub  12  along one or more axes during the manufacturing process. In one embodiment, workpiece platform  102  holds a metal block while hub machining device  104  forms hub  12  therefrom. Laser cladding device  106  is configured to deposit multiple layers  20  onto hub  12  to form each vane  14 . Vane machining device  108  is configured to machine oversized vanes  14  to form a desired shape and size for each vane  14 . For example, vane machining device  108  may remove superficial layers of oversized vane  14  to maintain a desired airfoil profile and/or remove surface disparities or surface porosity in order to form the desired vane contour. 
     During formation, each partially completed vane  14  may be alternated between laser cladding  106  and vane machining device  108 . As such, a first layer  20  of a first vane  14  may be formed on hub  12 . That first layer  20  may subsequently be machined by device  108  while laser cladding device  106  forms a first layer  20  of a second vane  14 . A second layer  20  of the first vane  14  may then be formed on the machined first layer  20  while vane machining device  108  machines the first layer  20  of the second vane  14 . The process may be alternated until the multiple layers  20  are deposited and machined to form the first and second vanes  14 . Additional vanes  14  may then be formed in the same manner. In alternate embodiments, rather than deposition of a single layer  20  followed by machining, a plurality of layers  20  may be formed or deposited on hub  12  before being machined by device  108 . In one embodiment, the first vane  14  and the second vane  14  are formed on diametrically opposed sides of hub  12  by rotating hub  12  to alternate the opposed first and second vanes  14  between oppositely oriented devices  106 ,  108 . In one embodiment, a second set of opposed devices  106 ,  108  are utilized such that four vanes  14  may be simultaneously formed on hub  12 . 
     In one embodiment, laser cladding device  106  and vane machining devices  108  are stationary and workpiece platform  102  rotates hub  12  about an axis  22  ( FIG. 1 ) to enable devices  106 ,  108  to work on various areas around the circumference of hub  12 . In other embodiments, laser cladding device  106  and vane machining device  108  are independently movable relative to workpiece platform  102  to work on hub  12 . 
     In another embodiment, hub machining device  104 , laser cladding device  106 , vane machining device  108 , and measuring device  110  may all be located in independent workstations  112  ( FIG. 5 ), and a robot or other component (e.g., platform  102 ) may move hub  12  from workstation to workstation  112  as fan rotor  10  is formed. In this way, most or all of workstations  112  may be constantly operated and multiple fan rotors  10  may be fabricated in a short period of time. 
     Workstation  100 ,  114  may include a controller  116  programmed to control the hybrid manufacturing process and one or more of devices  102  to  110 . As such, controller  116  may be in signal communication with devices  102 ,  104 ,  106 ,  108 , and  110 . As used herein, the term controller refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality. 
       FIG. 6  illustrates an exemplary method  150  of manufacturing fan rotor  10 . Method  150  includes, at step  152 , providing a block of material from which hub  12  will be formed. At step  154 , the block of material is machined with machining device  104  to form hub  12 . At step  156 , a laser cladding layer  20  of a first vane  14  is deposited or formed on hub  12  with laser cladding device  106 . At step  158 , hub  12  is rotated (e.g., 180°) such that previously deposited layer  20  is positioned proximate vane machining device  108 . 
     At step  160 , vane machining device  108  machines the previously formed layer  20  of the first vane  14  while laser cladding device  106  forms a new layer  20  of a second vane  14  on hub  12 . At step  162 , hub  12  is rotated to its previous position (e.g., approximately 180°) such that the machined layer  20  of the first vane  14  is positioned proximate the laser cladding device  106  and the newly formed layer  20  of the second vane  14  is positioned proximate vane machining device  108 . 
     At step  164 , vane machining device  108  machines the previously formed second layer  20  of the first vane  14  while laser cladding device  106  forms a second layer  20  of the first vane  14  on the previously machined first layer  20 . Steps  158  to  164  may be repeated until the first and second vanes  14  are completed. As such, each vane  14  is formed by forming a layer  20 , machining the layer  20 , forming another layer  20  on the previously machined layer  20 , and machining the newly formed layer  20 , and so on. The process is repeated until a vane  14  having a desired size and shape is formed. 
     At step  166 , completed vanes  14  may be measured by measuring device  110  to confirm if the vane  14  is within a predetermined tolerance of size and shape for that specific vane  14 . If measured vane  14  is not within the predetermined tolerance, at step  168 , vane  14  may undergo additional machining by vane machining device  108 . If measured vane  14  is within the predetermined tolerance, at step  170 , it is determined if additional vanes  14  need to be formed on hub  12 . If additional vanes  14  are required, at step  172 , steps  156  to  164  are performed to create additional vanes  14  on hub  12 . If additional vanes  14  are not required, the method ends at step  174 . 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.