Abstract:
A method of changing a composition and/or a density of gases inside of a hard disk drive. The method includes placing at least one tube into contact with an interior of a hard disk drive, and exchanging gases through the at least one tube. The exchange of gases occurs essentially simultaneously with another hard disk drive manufacturing process step.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the benefit of priority of U.S. Provisional Patent Application No. 61/327,328, filed Apr. 23, 2010. This patent application is also related to PCT patent application Ser. No. ______, filed on even date herewith and entitled “CHANGING THE COMPOSITION AND/OR DENSITY OF GASES INSIDE OF ASSEMBLIES DURING MANUFACTURING” (attorney docket no. 18523-0115WO1). The content of U.S. Provisional Patent Application No. 61/327,328 and of PCT patent application Ser. No. ______ (attorney docket no. 18523-0115WO1) is hereby incorporated by reference into this application as if set forth herein in full. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates to changing the composition and/or density of gases inside of assemblies, such as hard disk drives, during manufacturing. 
       BACKGROUND 
       [0003]    Operation of a hard disk drive can be affected by the composition and density of gas surrounding disk drive media and head assembly of the hard disk drive. Because the head assembly of a hard disk drive flies over the surface of the disk, the composition and density of the gas through which the head assembly flies can affect the flutter, resonance, and other critical parameters of the head assembly in conjunction with the gas. Similarly, the composition and density of the gas surrounding the spinning disk media can affect the turbulence caused by the spinning disk media. Because of the influence of the gas on the disk drive operation, the composition and density of the gas surrounding the disk drive head and media frequently needs to be controlled during disk drive manufacture. 
         [0004]    Modern hard disk drives often include a sealed enclosure around the moving parts of the hard disk drive, controlling the composition and density of the gas around these assemblies can include controlling the composition and/or density of the gas inside of the sealed enclosure. Known methods for controlling the composition and/or density of the gas inside the sealed disk drive enclosure include reducing the density of the air within the disk drive enclosure, or introducing a gas, such as helium, into the disk drive enclosure during certain manufacturing process steps. This manipulation of the composition and/or density of the gas present inside of the enclosure has been variously accomplished by placing the entire enclosure inside of a chamber in which the pressure and composition of the gases inside the chamber are controlled, or by exchanging gases through one or more apertures in the enclosure of the hard disk drive. In cases in which the gas or gases are exchanged through apertures in the hard disk drive enclosure, one or more of the apertures are fitted with a valve, either permanently or just for the duration of the manufacture. In other cases a sealing label may be used to temporarily or permanently open and close one or more of the apertures. 
         [0005]    Some known methods for exchanging gases inside the hard disk drive enclosure include processing a batch of hard disk drives at the same time in a chamber, or include manual operations to exchange the gas, or include additional process steps to complete, or include the addition of costly components to the hard disk drive 
       SUMMARY 
       [0006]    In general, this invention relates to changing the composition and/or density of gases inside of assemblies, such as hard disk drives, during manufacturing. 
         [0007]    One aspect of the invention features a method of changing the composition and/or density of gases inside of a hard disk drive. The method includes placing at least one tube into contact with the interior of a hard disk drive, and exchanging gases through the at least one tube. The exchange of gases occurs essentially simultaneously with another hard disk drive manufacturing process step. 
         [0008]    Another aspect of the invention provides a method of changing the composition and/or density of gases inside of a hard disk drive. The method includes placing at least one tube into contact with the interior of a hard disk drive, and exchanging gases through the at least one tube. The contact between the at least one tube and the interior of the hard disk drive is through at least one self-sealing membrane on the hard disk drive. 
         [0009]    Implementations of these methods may include one or more of the following features. 
         [0010]    In some implementations, the contact between the at least one tube and the interior of the hard disk drive is through at least one self-sealing membrane on the hard disk drive. 
         [0011]    The methods can be performed by automated machinery. 
         [0012]    In certain implementations, the at least one self-sealing membrane includes (e.g., is formed of) an elastomer. 
         [0013]    In some implementations, the at least one self-sealing membrane comprises a material selected from the group consisting of rubber, butyl, silicone, and fluoroelastomer (e.g., Viton®). 
         [0014]    In certain implementations, the contact between the at least one tube and the interior of the hard disk drive is through a one-way valve. 
         [0015]    In some implementations, the at least one tube includes at least a first tube and a second tube. In some cases, exchanging gases includes introducing one or more gases into the hard disk drive through the first tube and evacuating one or more gases from the hard disk drive though the second tube. The exchange of gases can be controlled by sensing a composition or density of the gases being evacuated from the hard disk drive, and terminating the exchange of gases when the composition or density meets predetermined criteria. 
         [0016]    In certain implementations, the exchange of gases proceeds for a predetermined amount of time. 
         [0017]    In some implementations, the exchange of gases proceeds until a predetermined volume of gases has been exchanged. 
         [0018]    In certain implementations, exchanging gases includes actuating a gas exchange mechanism. 
         [0019]    In another aspect, the invention provides an apparatus for the exchange of gases inside of a hard disk drive. The apparatus includes at least one tube adapted to carry a gas or vacuum, and a mechanism operable to place the at least one tube in contact with the interior of a hard disk drive. The at least one tube and the mechanism are adapted to cause the tube to penetrate a self-sealing membrane on the hard disk drive. 
         [0020]    Implementations of the apparatus may include one or more of the following features. 
         [0021]    In some implementations, the mechanism to place the at least one tube in contact with the interior of a hard disk drive is adapted to limit the penetration depth of the at least one tube. 
         [0022]    In certain implementations, the apparatus also includes a sensor for sensing the composition of the gases flowing through the at least one tube. 
         [0023]    In some implementations, the apparatus also includes a sensor for sensing the volumetric flow of the gases flowing through the at least one tube. 
         [0024]    In certain implementations, the at least one tube includes a first tube adapted to carry a gas or vacuum, and a second tube adapted to carry a gas or vacuum. The first tube is adapted to inject gases into a hard disk drive, and the second tube is adapted to evacuate gases from the same hard disk drive. 
         [0025]    According to another aspect, a hard disk drive includes at least one self-sealing membrane covering at least one aperture between an exterior of the hard disk drive and an interior of the hard disk drive. 
         [0026]    Implementations of the hard disk drive may include one or more of the following features. 
         [0027]    In some implementations, the at least one aperture and the at least one self-sealing membrane are adapted to allow the exchange of gases between the exterior of the hard disk drive and the interior of the hard disk drive via a tube that is caused to penetrate the self-sealing membrane. 
         [0028]    In certain implementations, the at least one self-sealing membrane is of a sufficient thickness to not substantially affect the hard disk drive&#39;s fitness for use. In some implementations, the at least one self-sealing membrane includes (e.g., is formed of) an elastomer. 
         [0029]    In certain implementations, the at least one self-sealing membrane includes a material selected from rubber, butyl, silicone, and fluoroelastomer (e.g., Viton®). 
         [0030]    In some implementations, the self-sealing membrane is adapted to be sufficiently flexible to allow gas pressures inside and outside of the hard disk drive to equalize. 
         [0031]    Implementations can include one or more of the following advantages. 
         [0032]    Some implementations allow multiple manufacturing process steps to be performed essentially asynchronously, to maintain the continuous nature of the manufacturing process. One advantage of maintaining a continuous flow is that it minimizes the idle time, where a partially completed hard disk drive is waiting for the next process step. Idle time can be an inefficient use of both factory space and inventory cost. 
         [0033]    In some implementations, a manufacturing method is provided that can operate continuously, is compatible with automation of the process steps, adds few or no additional process steps, and adds only very low-cost components to the hard disk drive. 
         [0034]    In certain implementations, a method is provided for injecting and/or evacuating gases from hard disk drives using automation, implemented in such a way that the method may be executed during some other hard disk drive manufacturing process step. 
         [0035]    In some implementations, a method is provided that may be practiced as a separate automated step that is of a small duration compared to many alternatives. 
         [0036]    In certain implementations, a methods is provided that may be practiced as part of a manual processing step that is of small duration and of lower likelihood of error compared to many alternatives. 
         [0037]    Other aspects, features, and advantages are in the description, drawings, and claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0038]      FIG. 1  is a perspective view of a hard disk drive. 
           [0039]      FIG. 2  is a perspective view of an end effector assembly. 
           [0040]      FIG. 3  is a perspective view of a hard disk drive tester. 
           [0041]      FIG. 4  is a perspective view of a hard disk drive with the self-sealing membranes of the current invention applied. 
           [0042]      FIG. 5  is a perspective view of an end effector assembly including a pivoting gas exchange mechanism illustrated in a quiescent position. 
           [0043]      FIG. 6  is a perspective view of an end effector assembly including a pivoting gas exchange mechanism illustrated in an engaged position. 
           [0044]      FIG. 7  is a schematic view of an end effector assembly and associated gas-handling and gas-sensing equipment. 
       
    
    
       [0045]    Like reference symbols in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0046]    Referring to  FIG. 1 , a hard disk drive  400  includes a cover  440  that encloses disk media, a head gimbal assembly (HGA), and other parts of the disk drive not shown in  FIG. 1 . The cover  440  may include one or more apertures  430  that allow gases to exchange between the interior and the exterior of the hard disk drive enclosure. At the end of manufacture, the apertures  430  may be covered by sealing labels  410  to prevent contamination from entering the hard disk drive  400 . A hard disk drive  400  may also include a vent  450 , which serves to equalize the interior and exterior air pressure during the operating life of the hard disk drive  400 . When a vent  450  is present, an internal filter, flexible membrane, or labyrinth connection may be used to prevent contamination from entering the hard disk drive  400 . 
         [0047]    In some hard disk drive manufacturing processes, the hard disk drive  400  may be transported by an automated transporter (see, e.g., item  610 ,  FIG. 3 ). Referring to  FIG. 2 , the automated transporter may include an end effector assembly  200 , which may include a camera  220 , a light source  230 , and a mechanical actuator  210 . The hard disk drive  400  may be carried by a carrier  300  ( FIG. 3 ) that is gripped by the end effector assembly  200  via the mechanical actuator  210 . 
         [0048]    Referring to  FIG. 3 , in some hard disk drive manufacturing processes, the automated transporter  610  attached to the end effector  200  may form part of a larger manufacturing system, for example a hard disk drive test system  600 . Such a system may use the automated transporter  610  to transport disk drives from an input/output station  620  to and from test slots  630  housed in racks  640 . In the example shown in  FIG. 3 , the automated transporter  610  carries the disk drive in a carrier  300 , gripped by an end effector assembly  200 . 
         [0049]    Referring to  FIG. 4 , in some implementations, the hard disk drive  400  has apertures  430  in its cover  440 , extending from the interior space of the hard disk drive  400  to the exterior, each covered by a self-sealing membrane  420 . The self-sealing membrane  420  may consist essentially of an elastomer or elastomeric compound. In some implementations, the self-sealing membrane may be of the type that is known in medicine as a septa seal, which is membrane that separates two areas, that can be punctured by a needle, cannula or the like, and which self-seals after the puncturing element is removed. An example is the Longevity™ septa available from SSP Companies. The self-sealing membrane  420  may consist essentially of a suitable elastomer, including but not limited to natural rubber, butyl, silicone, fluoroelastomer (e.g., Viton®); or other self-sealing material. The self-sealing membrane  420  is applied in such a way that, together with the cover  440 , it forms an essentially gas-tight seal around the interior of the hard disk drive  400 . The self-sealing membrane  420  can be of such a thickness that it may be left in place for the life of the hard disk drive  400  without impeding the fitness of the hard disk drive  400  for use. To achieve this thickness, while also being sufficient to form an essentially gas-tight seal, it may be beneficial for the self-sealing membrane  420  to partially intrude into the interior of the hard disk drive  420 . Alternatively, if the self-sealing membrane  420  is not sufficient to form an essentially gas-tight seal of sufficient effectiveness or duration, a sealing label may be applied to cover or replace the self-sealing membrane  420 , as part of some final hard disk drive manufacturing process step. 
         [0050]    In some implementations, the use of a self-sealing membrane  420  to cover an aperture  430  may obviate the need for a vent  450 , as well as any corresponding filter. The flexible nature of the self-sealing membrane  420  may be sufficient to equalize the pressure inside and outside of the hard disk drive  400 . 
         [0051]    Referring to  FIG. 5 , in some implementations, an end effector assembly  200  is shown gripping a carrier  300  holding a hard disk drive  400 . The end effector assembly  200  is shown also comprising a pivoting gas exchange mechanism which includes two L-shaped assemblies  500 , each of which includes a hollow needle  510 . The L-shaped assemblies  500  are shown in a position where the hollow needles  510  are held clear of the hard disk drive  400 . In this position, whatever density and composition of the gas present inside of the enclosure of disk drive  400  is maintained, and the hard disk drive  400  may be moved into or out of the carrier  300  essentially without hindrance. 
         [0052]    Referring to  FIG. 6 , in some implementations, an end effector assembly  200  is shown with the two L-shaped assemblies  500  actuated so that the hollow needles  510  penetrate the self-sealing membranes  420 . In this position, gas or vacuum may be applied under positive or negative pressure through either one or both of the hollow needles  510 , to perform an exchange or evacuation of the gases present inside of the hard disk drive  400 . With reference to  FIG. 7 , the hollow needles  510  are connected by hoses, tubes, conduits, pipes, or other gas-directing means  710  to other gas-handling equipment  720 . The connection may incorporate valves  730  or other means for controlling the flow of gas, and gas sensing equipment  740  for sensing the composition, flow, or volume of the gas flowing in to or out of the hard disk drive  400 . The gas-handling equipment  720  may be one of, but is not limited to, vacuum pumps, gas tanks, gas generators, and compressors. The gas-sensing equipment  740  may be one of, but not limited to, mass flow controllers, gas spectrometers, and oxygen sensors. The L-shaped assemblies  500  may be actuated by electrical, mechanical, or pneumatic means incorporated in the end effector assembly  200 . The L-shaped assemblies  500  may be similarly retracted by opposite electrical, mechanical, or pneumatic means. The hollow needles  510  are preferably of a non-coring type that is adapted for use with self-sealing membranes, and of such a length that the depth of their penetration in to the hard disk drive  400  is limited by the shoulder of the L-shaped assembly  500  to a distance that is sufficient to penetrate the self-sealing membrane  420  but not sufficient to damage any internal component of hard disk drive  400 . 
         [0053]    In some implementations, a new gas exchange process would be integrated with an existing hard disk drive manufacturing process step in a hard disk drive test system  600  as follows:
       1. A hard disk drive  400  is introduced into the hard disk drive test system  600  via the input/output station  620 .   2. The automated transporter  610  retrieves the hard disk drive  400  from the input/output station  620  by first retrieving a carrier  300  from an empty test slot  630 , and then transferring the disk drive  400  from the input/output station  620  to the carrier  300 . The L-shaped assemblies  500  are retracted throughout this step, so the hard disk drive  400  may be transferred to the carrier  300  without hindrance.   3. Immediately after the hard disk drive  400  is removed from the input/output station  620 , the L-shaped assemblies  500  are activated. This actuation causes the L-shaped assemblies  500  to pivot towards the top of the hard disk drive  400 , so that the hollow needles  510  penetrate the self-sealing membranes  420 .   4. As the hard disk drive  400  is transported from the input/output station  620  to the test slot  630 , the gas-handling equipment is activated to cause a gas exchange or evacuation, with the aim of changing the composition, the density, or both, of the gas inside of the hard disk drive  400 . In some implementations, the gas exchange or evacuation may be limited by time and flow. In other implementations, the gas or vacuum exchange may be limited by volume. In yet other implementations, the gas exchange or evacuation may be limited by sensing the composition of the gas flowing out of the hard disk drive  400 , and maintaining the gas flow until such time as the composition and density of the gas meets predetermined criteria.   5. Before the hard disk drive is inserted into the test slot  630 , the L-shaped assemblies  500  are refracted. This retraction causes the L-shaped assemblies  500  to pivot away from the hard disk drive  400 , thus causing the self-sealing membranes  420  to seal, and the hard disk drove  400  to be available for insertion in the test slot  630  without hindrance.       
 
         [0059]    In some implementations, a similar set of actions causes the gas in the hard disk drive  400  to be exchanged or evacuated while being transported from the test slot  630  to the input/output station  620 . 
         [0060]    In some implementations, the self-sealing membranes  420  may be covered or replaced by an adhesive sealing label as part of a later process step. 
         [0061]    In some implementations, the vent  450  may be covered as part of an earlier manufacturing process step. In some implementations, the vent  450  may be uncovered as part of a later manufacturing process step. 
         [0062]    A number of implementations of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. 
         [0063]    For example, in some implementations, the gas may be exchanged by injecting pressurized gas through a first of the two apertures  430 , and evacuating the previous gas through a second of the two apertures  430 . 
         [0064]    In some implementations, a single aperture  430  may be present, and the gas is exchanged by first evacuating essentially all of the gas through the single aperture  430 , and subsequently gas is injected through the same aperture  430 . 
         [0065]    In some implementations, more than two apertures  430  and self-sealing membranes  420  may be present. 
         [0066]    In some implementations, the process or apparatus may be used to alter the density of the gas inside of the hard disk drive enclosure, up to and including creating a vacuum. 
         [0067]    In some implementations, one or both of the hollow needles  510  may be replaced by a cannula, pipe, or other gas-carrying tube. 
         [0068]    In some implementations, the L-shaped assemblies  500  may have other shapes that are sufficient to carry the hollow needles  510 . 
         [0069]    In some implementations, the action by which the hollow needle  510  or its equivalent is caused to penetrate the self-sealing membrane  420  is not pivotal, but linear, or rotary, or some other motion sufficient to translate the tip of hollow needle  510  a sufficient distance through the self-sealing membrane  420  into the hard disk drive  400 . 
         [0070]    In some implementations, one or more of the self-sealing membranes  420  is replaced by a mechanical valve, such as a ball valve, a flapper valve, a reed valve, or any other such valve that will remain closed as long as the gas pressure inside of the hard disk drive  400  exceeds that of the surrounding environment. In such cases, any process for the exchange of gases inside of the hard disk drive  400  must end in such a state that the internal pressure of the hard disk drive  400  exceeds that of the surrounding environment, if it is required that the valve remain closed. 
         [0071]    In some implementations, one or more of the self-sealing membranes  420  is replaced by a mechanical valve, such as a ball valve, a flapper valve, a reed valve, or any other such valve that will remain closed as long as the gas pressure inside of the hard disk drive  400  is less than that of the surrounding environment. In such cases, any process for the exchange or evacuation of gases inside of the hard disk drive  400  must end in such a state that the internal pressure of the hard disk drive  400  is less than that of the surrounding environment, if it is required that the valve remain closed. 
         [0072]    In some implementations, the action that causes the hollow needles  510  to penetrate the self-sealing membrane  420  is that of moving the hard disk drive  400 , rather than that of moving the L-shaped assemblies  500 . 
         [0073]    In some implementations, the hard disk drive  400  is gripped directly by a mechanical actuator, or is held statically in a fixture, or is made available to the gas exchange or evacuation mechanism by some means other than by being held in a carrier  300 . 
         [0074]    In some implementations, the position of the apertures  430  and the self-sealing membranes  420  may be elsewhere on the hard disk drive  400  besides on the cover  440 . 
         [0075]    In some implementations, the gas exchange or evacuation process is executed during some hard disk drive manufacturing process step other than transport inside of a hard disk drive tester  600 , including but not limited to: 
         [0076]    transport or some other handling operation inside of some other type of hard disk drive manufacturing equipment; 
         [0077]    transport of the hard disk drive  400  around a manufacturing facility; 
         [0078]    loading or unloading the hard disk drive  400  to or from a conveyor; 
         [0079]    during test of the hard disk drive  400 , for example inside of the test slot  630 ; and 
         [0080]    inside of a clean room during some manufacturing process there. 
         [0081]    In some implementations, the gas exchange or evacuation process is executed as a separate manufacturing process step, not combined with some other manufacturing process step. In such implementations, the simplicity, speed, and reduced incidences of errors characteristic of the current invention are still an improvement over existing processes. 
         [0082]    In some implementations, the gas exchange or evacuation process is executed essentially manually, with a manual execution of any or all of: 
         [0083]    the actuation of the L-shaped assemblies  500 ; 
         [0084]    the gas exchange or evacuation; and 
         [0085]    the disengagement of the L-shaped assemblies  500 . 
         [0086]    In such manual implementations of the gas exchange or evacuation process, the simplicity, speed, and reduced incidences of errors characteristic of the current invention are still an improvement over existing processes. 
         [0087]    Accordingly, other implementations are within the scope of the following claims.