A door assembly comprises a rectangular door frame that has a first, second, third, and fourth frame member. The first frame member has an outer surface that has a first pair of parallel slots. A first parallel flange protrudes from and perpendicular to the outer surface between the parallel slots. A vane extends from the first frame member to the second frame member between the third and fourth frame members. The vane has a first end that includes a pair of parallel flanges fitted into the parallel slots such that a rear surface of the first planar flange is arranged between rear edges of the first parallel flanges. A bar is mounted to the rear surface of the first planar flange and configured to hold the rear edges of the first parallel flanges in substantially the same plane as the rear surface of the first planar flange.

BACKGROUND 
     Aspects of the present disclosure relate to server mounting infrastructure, more particular aspects relate to server door construction. 
     Typical server doors are designed to allow air to flow through the server door, while preventing noise and electromagnetic radiation from spreading from one side of the door to the other. These conflicting design objectives lead to server doors of varying complexity, which often causes the doors to be expensive to manufacture and assemble. 
     SUMMARY 
     Some embodiments of the present disclosure can be illustrated by an assembly for a door. The assembly comprises a rectangular door frame that has a first, second, third, and fourth frame member. The first frame member comprises an outer surface that has a first pair of parallel slots. The outer surface has a first planar flange arranged between the first pair of parallel slots and protrudes out from and perpendicular to the outer surface. The assembly further comprises a vane extending from the first frame member to the second frame member and between the third and fourth frame members. The vane has a first end that includes a first pair of parallel flanges fitted into the first pair of slots, such that a rear surface of the first planar flange is arranged between rear edges of the first parallel flanges. The door assembly also comprises a bar mounted on the rear surface of the first planar flange. The bar is mounted such that it holds the rear edges of the first parallel flanges in substantially the same plane as the rear surface as the first planar flange. 
     Some embodiments of the present disclosure can be illustrated by a method of assembling a door. A first end of a first vane is attached to a first frame member of the door. The attaching includes inserting a first pair of parallel flanges on the first end into a first pair of parallel slots on an outer surface of the first frame member. The parallel flanges are inserted into the slots such that a rear surface of a first planar flange is arranged between rear edges of the first parallel flanges. The attaching also includes mounting a first bar to the rear surface of the first planar flange such that the bar holds the rear edges of the first parallel flanges in substantially the same plane as the rear surface of the first planar flange. A second end of the first vane is then attached to a second frame member of the door. The second frame member is opposite the first frame member with respect to the door. The attaching the second end includes inserting a second pair of parallel flanges on the second end into a second pair of parallel slots on an outer surface of the second frame member. The parallel flanges are inserted into the slots such that a rear surface of a second planar flange is arranged between rear edges of the second parallel flanges. The attaching the second end also includes mounting a second bar to the rear surface of the second planar flange such that the second bar holds the rear edges of the second parallel flanges in substantially the same plane as the rear surface of the second planar flange. Finally, the attaching the second end further comprises mounting the first sub member to a second sub member of the second frame member, the second sub member being fixedly attached to the door assembly. 
     The above summary is not intended to describe each illustrated embodiment or every implementation of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings included in the present application are incorporated into, and form part of, the specification. They illustrate embodiments of the present disclosure and, along with the description, serve to explain the principles of the disclosure. The drawings are only illustrative of certain embodiments and do not limit the disclosure. 
         FIG. 1A  depicts the frame of a server-rack door to which insulating components may be added, in accordance with embodiments. 
         FIG. 1B  depicts a vane that may be added to a server-rack door, in accordance with embodiments. 
         FIG. 1C  depicts the frame of a server-rack door to which multiple vanes have been added, in accordance with embodiments. 
         FIG. 2  depicts the end of a vane that may be securely attached to a server door, in accordance with embodiments. 
         FIG. 3  depicts a frame member with which the end of a vane may interface, in accordance with embodiments. 
         FIG. 4A  depicts a frame member and end of a vane interfacing, in accordance with embodiments. 
         FIG. 4B  depicts the end of a vane secured with a securing bar, in accordance with embodiments. 
         FIG. 4C  depicts an alternative view of a vane secured with a securing bar, in accordance with embodiments. 
         FIG. 5  depicts the ends of multiple vanes interfacing with a frame member, in accordance with embodiments. 
         FIG. 6A  depicts a view of a first frame sub member installed in a server door frame, in accordance with embodiments. 
         FIG. 6B  depicts a view of a second frame sub member that may attached to the first frame sub member, in accordance with embodiments. 
         FIG. 6C  depicts a view of the second frame sub member attached to the first frame sub member, in accordance with embodiments. 
         FIG. 7A  depicts a cross-sectional view of a vane, in accordance with embodiments. 
         FIG. 7B  depicts a cross-sectional view of a flexible insulating member, in accordance with embodiments. 
         FIG. 7C  depicts a cross-sectional view of a flexible insulating member inserted into a vane, in accordance with embodiments. 
         FIG. 7D  depicts a cross-sectional view of a flexible insulating member inserted into a vane in an alternate orientation, in accordance with embodiments. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
     DETAILED DESCRIPTION 
     Aspects of the present disclosure relate to server mounting infrastructure, more particular aspects relate to server door construction. While the present disclosure is not necessarily limited to such applications, various aspects of the disclosure may be appreciated through a discussion of various examples using this context. 
     Some components in specialized computer systems, such as large servers, are typically produced in small volumes. In some cases this may be due to those components being custom designed for each use case. In some other cases this may be due to those components being used in extremely high-end products, the market for which may be small. These small volumes oftentimes do not justify the up-front expense of developing solutions to automate tooling or assembly of the related components. Server rack doors, for example, are typically built at volumes that do not justify machine welding of door components, such as the aerodynamic components used to direct airflow into or out of the server rack or insulation components used to stop electromagnetic radiation or the noise of server fans from spreading to the server room. Human labor may be utilized for these components, which may be very expensive per part. Further, the cost of human labor increases quickly as the complexity or intricacy of a component or assembly process increases. Thus, server-rack doors are often designed to keep labor costs low. These basic server-rack-door designs are often less functional than optimal designs that may cost more to produce. 
     Some embodiments described in the present disclosure improve upon server-rack-door technology by providing component design and a method of assembly that may be performed by human labor quickly while still producing efficient airflow and acoustic and electrical insulation. In some embodiments little to no welding of door components may be required. Some embodiments may hide the mounting points of all door components, resulting in an aesthetically appealing design. Some embodiments may utilize similar connections across multiple components, enabling the same or similar construction methods to be utilized across multiple server-rack doors designed for different use cases. 
       FIG. 1A  depicts the Frame  100  of a server-rack door to which aerodynamic and insulating components may be added (referred to herein as “vanes”). Frame  100  may have two Side Members  102 , Top Member  104 , and Bottom Member  106 . Together these four members may define Opening  108 , through which air may flow to cool components of the server.  FIG. 1B  depicts Vane  110 , which may be added to Frame  100 . In some embodiments Vane  110  may interface with any of Top Member  104 , Bottom Member  106 , and Side Members  102 . For example,  FIG. 1C  illustrates multiple Vanes  110  interfacing with Bottom Member  106 . In some embodiments Vanes  110  may interface with Top Member  104  or both Top Member  104  and Bottom Member  106 . In other embodiments, Vanes  110  may span the opening in a perpendicular direction by interfacing with one or both of Side Members  102 . 
       FIG. 2  illustrates one embodiment of the end of a vane that may be securely attached to a server door without welding or other significant human labor. The end of Vane  200  has two parallel Flanges  202 . Flanges  202  are “L shaped,” which creates a gap between the vertical portion of each Flange  202  and the body of Vane  200 . These Flanges  202  may be inserted into an opening on the frame of a server door and used to secure Vane  200  in place in the door. Flanges  202 , in this embodiment, have Rear Edge  204  and Side Edge  206 , one or both of which may be utilized in bracing Vane  200  when Flanges  202  are inserted into a server door. 
     In some embodiments, other flange shapes may be utilized with similar effects. In some embodiments, for example, Flanges  202  may be curved to create a hook shape, rather than bent as shown. In other embodiments Flanges  202  may not exhibit any bend or curve, but may protrude straight from Vane  200 . In this embodiment two Flanges  202  are shown on either side of the end of Vane  200 , which may increase stability of Vane  200  when mounted. However, in some embodiments different positions of Flanges  202  may be utilized. 
       FIG. 3  illustrates one embodiment of a frame member with which the end of a vane may interface. Opening  300  is found on Surface  302 , which may be the end of a server-door frame (e.g., Bottom Member  106  of  FIG. 1C ). The ends of a vane may be inserted through Opening  300  and into Slots  304  to secure the vane in place. For example, Flanges  202  of  FIG. 2  may be inserted into Slots  304  such that the gap between the vertical portion of the L-shaped Flange  202  and Vane  200  are positioned on opposite ends of the frame member (e.g., Bottom Member  106  of  FIGS. 1A & 1C ). This may prevent Vane  200  from separating from the frame member without first being lifted out of Slots  304 . Note that, in this embodiment, Opening  300  is significantly greater than Slots  304 . This may enable vane ends of different shapes to interface with the frame member. In other embodiments, however, Opening  300  may be of a shape and size corresponding to a specific vane end (e.g., an opening corresponding to Flanges  202  of Vane  200  may be limited to two parallel slots). 
     The frame member of  FIG. 3  also has Planar Flange  306 . In some embodiments Planar Flange  306  may be used as a structural support for additional components that may assist in securing the end of a vane to the frame member. In this embodiment such components may attach to the flange through Hole  308  (e.g., by means of a bolt), but in other embodiments other attachment mechanisms may be used. 
       FIGS. 4A-4C  illustrate one embodiment of the end of a vane such as Vane  200  of  FIG. 2  interfacing with a frame member such as in  FIG. 3 . In  FIG. 4A , Flanges  402  have been inserted into the slots of the frame member. Rear Edges  404  of Flanges  402  may be flush with Rear Surface  408  of Flange  406 . In this illustration, no securing mechanism is present to prevent Flanges  402  from separating from Flange  406 . In some embodiments a securing member may be added to prevent Flanges  402  and Flange  406  from separating. Such an embodiment is shown in  FIG. 4B . Securing Bar  410  lies against Rear Edges  404  and Rear Surface  408  (not shown), preventing Flanges  402  from separating from Flange  406  (not shown). In this illustration Securing Bar  410  is held in place in part by Bolt  412 , which may extend through a hole in Flange  406 . In some embodiments Bolt  412  may be tightened to an extent that Securing Bar  410  prevents Flanges  402  from vibrating in place. In other embodiments Securing Bar  410  may be held in place by other mechanisms, such as a clamp, adhesive, a welded bond, any of which may be located near Flange  406  or elsewhere (e.g., on a different flange on the same frame member or at either end of the frame member). 
       FIG. 4C  provides an alternative view of Securing Bar  410  fastening Flanges  402  (and thus the connected vane) in place. In  FIG. 4C , Flanges  402  are connected to Vane  414 , and inserted through a pair of slots in Frame Member  416 .  FIG. 4C  shows that the horizontal portion of Securing Bar  410  interfaces with the Rear Surface  408  (not shown) of Flange  406  and Rear Edges  404  (not shown) of Flanges  402 . In this embodiment, only one Vane  414  has been inserted into an opening on Frame Member  416 . However, three other openings are present, each of which may have flanges corresponding to Holes  418  in Securing Bar  410 . In this embodiment, additional vanes with L-shaped flanges may be added and held in place by Securing Bar  410 . Further bolts may be inserted through Holes  418  to increase the ability of Securing Bar  410  to hold the vanes in place. In other embodiments Frame Member  416  may contain only the opening corresponding to Vane  414 , in which case Securing Bar  410  may be significantly shorter, and Holes  418  may not be present. Alternatively, Securing Bar  410  as shown (with Holes  418 ) may be utilized in embodiments with a small number of vanes (e.g., one or two vanes). In other words, Securing Bar  410  may be utilized in various embodiments in which the number of openings in the frame member (and the corresponding number of vanes to secure) may differ from the length of Securing Bar  410  and the number of holes in Securing Bar  410 . 
       FIG. 5  illustrates the modularity with which the solutions described in the present disclosure may be used. In  FIG. 5 , two rows of Vanes  500  have been attached to Frame Member  502 . In this embodiment, the bottom row has four vanes, whereas the top row has five vanes. Each of the vanes contain a set of L-shaped Flanges  504 . The top-row vanes are held in place by Securing Bar  506 , and the bottom-row vanes are held in place by Securing Bar  508 . In this embodiment Securing Bar  506  and Securing Bar  508  are interchangeable parts, and thus Securing Bar  508  contains unused Hole  510 . In some embodiments either the top row or bottom row may contain more than five vanes, in which case one or both of Securing Bar  506  and Securing Bar  508  may be longer, or all securing bars may have five holes, but multiple securing bars may be used on rows with more than five vanes. In other embodiments Frame Member  502  may have more than two rows of vanes, in which case more securing bars may be used. 
     In the embodiment illustrated by  FIG. 5 , many parts may be interchangeable to other parts used for the same purpose. This may reduce the cost of designing and setting up the manufacturing processes for the components of multiple different server-rack door designs (e.g., a door with four rows with four vanes and a door with one row of three vanes may each use securing bars with six holes). In some instances this may also enable components to be obtained at high-volume prices. In this embodiment, for example, all nine Vanes  500 , both Securing Bar  506  and Securing Bar  508 , and all bolts may be substantially identical to similarly used components (e.g., each Vane  500  is substantially identical to each other Vane  500 ) such that they are interchangeable. Because these substantially identical parts may, in some embodiments, be used in other server-door designs as well, only one manufacturing solution may be necessary for multiple implementations, even when those implementations differ. This increases the ability to and benefit of ordering components at high volume. 
     In this embodiment the openings in Frame Member  502  that correspond to the top-row vanes differ in design from the openings corresponding to the bottom-row vanes. Namely, the top-row openings are not bound on all four sides. This may reduce the time and effort required to insert the L-shaped Flanges  504  for the top-row Vanes  500  into the openings, which may reduce the human-labor cost of the server-door assembly. In some other embodiments, however, there may be cost savings in the top and bottom row openings being interchangeable (e.g., the cost to machine a single opening design may be significantly less than the cost to machine two opening designs), in which case the openings may be substantially identical. 
       FIGS. 6A-6C  illustrate an embodiment in which a frame member is composed of multiple sub members that may be separated to increase the ease with which vanes may be attached to the frame member. This may also reduce the human-labor cost of the server-door assembly.  FIG. 6A  shows a section of a Door Frame  600  with a frame Sub Member  602 . Sub Member  602  has a series of Holes  604  through which a second frame sub member may be attached to Sub Member  602 .  FIG. 6B  illustrates Sub Member  606  separated from a server-door assembly. Sub Member  606  has two rows of openings into which the end of a vane may be inserted, similar to Frame Member  502  of  FIG. 5 . Protruding from Sub Member  606  are Flanges  608  at the locations of the bottom-row openings and Flanges  610  at the locations of the top-row openings. Both Flanges  608  and  610  contain Holes  616 , through which a securing bar may be attached to the flanges. However, each of Flanges  610  contain an additional Hole  612  which, in this embodiment, corresponds to one of Sub Member  602 's Holes  604 . 
       FIG. 6C  illustrates Sub Member  606  attached to Sub Member  602 . Screws  614  have been inserted through Holes  612  and  604 , securing Sub Member  606  to Sub Member  602 . In some embodiments this attachment may be performed before vanes have been attached to Sub Member  606 . However, in the embodiment illustrated in  FIGS. 6A-6C  it may be beneficial to attach vanes prior to attaching Sub Member  606  to Sub Member  602 ; Sub Member  602  may impede access to Flanges  608  once Sub Member  606  is attached. Further, attaching vanes to Flanges  608  and  610  prior to attaching Sub Member  606  may increase the speed at which the vanes may be inserted to corresponding openings on an opposite frame member (e.g., opposite the door frame of Sub Member  606 ). This may reduce the cost of human labor in assembling the server door. 
     In this embodiment Sub Members  606  and  602  are connected through Holes  612  and  604 . However, in some embodiments each of Flanges  610  may be designed with only Hole  616 . In these embodiments Sub Members  606  and  602  may be connected through Hole  616 , the same hole through which a securing bar is attached to Flanges  610 . In other embodiments Sub Members  606  and  602  may be connected through another means, such as a clamp, adhesive, a welded bond, or others. 
       FIGS. 7A-7D  illustrate a cross-section profile of one embodiment of a vane with a flexible insulating member installed in multiple configurations. Vane  700  may be a vane design that may be installed in a frame member according to any of  FIGS. 1-5 . Vane  700  has Cavity  702 , into which an insulating member may be installed to reflect or absorb sound and electromagnetic radiation or to redirect air flow. Vane  700  has a Tab  704  on each side of Cavity  702 . Tab  704  may be used to secure insulating members in Cavity  702 , as will be shown in connection with  FIGS. 7C and 7D . In some embodiments, Tab  704  may extend the entire length of Vane  700 . In other embodiments, one shorter Tab  704  may be located only at one point throughout the length of Vane  700  (e.g., the middle) or multiple shorter Tabs  704  may be located throughout the length of Vane  700  (e.g., at each end and at the middle). In some embodiments Vane  700  may have a tab only on one side of Cavity  702 . 
       FIG. 7B  illustrates one embodiment of a cross section of an Insulating Member  706  that may be inserted into Cavity  702 . Insulating Member  706  may be composed of any material with sufficient flexibility to be inserted into Cavity  702  past Tabs  704  and with insulating properties. For example, Insulating Member  706  may be composed of open-cell polyurethane foam or closed-cell polystyrene or neoprene foam. Insulating Member  706  has a pentagon cross section in this embodiment, but in other embodiments it may take other forms (e.g., a square, a kite, or a regular or irregular hexagon). 
       FIG. 7C  illustrates one embodiment in which Insulating Member  706  may inserted into Cavity  702 . This orientation of Insulating Member  706  may be beneficial when space limitations preclude Insulating Member  706  from spreading past Tabs  704  or for airflow considerations. Insulating Member  706  has been deformed by Tabs  704 , which, in this embodiment, prevent Insulating Member  706  from exiting the cavity. In this embodiment Insulating Member  706  may also be prevented from vibrating or rattling in Cavity  702  by the pressure placed upon it by Tabs  704 . In some embodiments Insulating Member  706  may be slightly shorter, such that Tabs  704  only make contact with the top of Insulating Member  706  and do not squeeze the sides of Insulating Member  706 . This may make Insulating Member  706  less likely to exit Cavity  702 , but may also make Insulating Member  706  more likely to vibrate within Cavity  702 . 
       FIG. 7D  illustrates a second embodiment in which Insulating Member  706  may be inserted into  FIG. 7D . This orientation may be beneficial to direct airflow to either side of Vane  700  in embodiment in which space limitations are less constricting than in  FIG. 7C . In this embodiment Tabs  704  again deforms Insulating Member  706 , which may again prevent Insulating Member  706  from exiting Cavity  702 . 
     As  FIGS. 7C and 7D  show, Insulating Member  706 , if flexible, may be installed in multiple orientations in different embodiments. This may enable assemblers of server-rack doors to order a high volume of one flexible-insulating-member design, which may reduce the cost of the part. Further, because the insulating member is flexible, it can be inserted into the cavity of a vane with ease by a human installer without the use of any tools, which may reduce the cost of human labor. 
     The descriptions of the various embodiments of the present disclosure have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.