PATENT DOCUMENT

Publication Number: US-9561576-B2
Application Number: US-201414185074-A
Country: US
Kind Code: B2

Title: Cylindrical lapping

Abstract:
The described embodiments relate generally to lapping operations and related systems and apparatuses. Various embodiments of lapping tables are described for applying a lapping operation to a non-planar surface of a workpiece. For example, methods and apparatus are described which allow a lapping operation to be applied to a curved outer surface portion of a cylindrical workpiece. Lapping of non-planar outer surfaces of workpieces is conducted by rotating the workpieces during the lapping operations.

Claims:
What is claimed is: 
     
       1. A method for performing a lapping operation, the method comprising:
 providing a lapping table comprising an abrasive disc defining a substantially planar abrasive surface; 
 during a first rotation, rotating the abrasive disc about a first axis, wherein the first axis extends substantially perpendicular to the substantially planar abrasive surface; 
 during a second rotation, rotating a workpiece about a second axis, the second axis being non-parallel to the first axis; and 
 during a third rotation, rotating the workpiece about a third axis offset from and substantially parallel to the first axis, such that a three-dimensional outer surface of the workpiece is in contact with and lapped by the substantially planar abrasive surface of the rotating abrasive disc, wherein the first, second and third rotations are driven independent of each other. 
 
     
     
       2. The method of  claim 1 , wherein the workpiece is a cylindrical workpiece and the second axis extends between a first and second end surface of the cylindrical workpiece. 
     
     
       3. The method of  claim 2 , wherein rotating the cylindrical workpiece about the second axis comprises engaging the first and second end surfaces of the cylindrical workpiece. 
     
     
       4. The method of  claim 3 , wherein the pressure applicator includes an actuator that is configured to apply a variable amount of pressure between the cylindrical workpiece and the substantially planar abrasive surface of the abrasive disc. 
     
     
       5. The method of  claim 3 , wherein a controller is in communication with the pressure applicator to adjust an amount of pressure that is applied to the cylindrical workpiece. 
     
     
       6. The method of  claim 2 , wherein the lapping table further comprises a pressure applicator, and the pressure applicator engages the first and second end surfaces of the cylindrical workpiece. 
     
     
       7. The method of  claim 1 , wherein the first rotation, the second rotation, and the third rotation are concurrently driven. 
     
     
       8. The method of  claim 1 , further comprising pressing the workpiece against the substantially planar abrasive surface of the abrasive disc. 
     
     
       9. The method of  claim 1 , wherein the lapping table further comprises at least one conditioning ring that is coupled to the workpiece such that the at least one conditioning ring presses the workpiece against the substantially planar abrasive surface of the abrasive disc during the lapping operation. 
     
     
       10. The method of  claim 9 , wherein the lapping table further comprises at least one support member that is coupled to the at least one conditioning ring. 
     
     
       11. The method of  claim 10 , wherein the at least one support member comprises an inner engagement mechanism having a roller that is configured to rotate the at least one conditioning ring. 
     
     
       12. The method of  claim 1 , wherein the first, second and third rotations are driven independent of each other by a controller. 
     
     
       13. The method of  claim 12 , wherein the controller is configured to control at least one finishing parameter during the lapping operation to produce a pre-determined surface finish on the workpiece. 
     
     
       14. The method of  claim 13 , wherein the at least one finishing parameter comprises rotational speed, direction, or pressure. 
     
     
       15. The method of  claim 1 , wherein a second rotational mechanism causes the second rotation and a third rotational mechanism causes the third rotation. 
     
     
       16. The method of  claim 1 , wherein the third axis is offset by a non-zero distance from the first axis. 
     
     
       17. The method of  claim 1 , wherein the method is configured to be executed by a non- transitory computer readable medium of a computing device. 
     
     
       18. The method of  claim 1 , wherein the abrasive disc is coupled to a first rotational mechanism. 
     
     
       19. The method of  claim 1 , wherein the rotation of the workpiece along the third axis is in a direction that is opposite the first axis. 
     
     
       20. The method of  claim 1 , wherein the workpiece is characterized as having a substantially even surface finish subsequent to the lapping operation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit priority under 35 U.S.C §119(e) to U.S. Provisional Application No. 61/832,555, filed on Jun. 7, 2013, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The described embodiments relate generally to lapping. In particular a method for applying lapping to a three-dimensional object (e.g., a cylindrical object) is disclosed. 
     BACKGROUND 
     Components employed to form various devices such as computing devices often undergo numerous manufacturing operations during the production thereof. Additive manufacturing processes add material to form a component. By way of example, injection molding may be employed to form a component. Conversely, subtractive manufacturing processes remove material from a workpiece or substrate to form a component. For example, material may be machined from a substrate to form the component. In some embodiments both additive and subtractive processes may be employed to form a component, depending on the particular desired final configuration of the component. 
     Computer numerical control (CNC) machining is one example of a type of subtractive manufacturing process commonly employed to form components. CNC machining typically employs a robotic assembly and a controller. The robotic assembly may include a rotating spindle to which a milling cutter, or alternate embodiment of cutter, is coupled. The milling cutter includes cutting edges that remove material from a workpiece to form a component defining a desired shape and dimensions. In this regard, the controller directs the robotic assembly to move the milling cutter along a machining path that forms the component. However, CNC machining and various other manufacturing processes may not provide a desired surface finish. 
     In this regard, the workpiece may undergo finishing operations such as lapping operations in order to produce a desired surface finish. Lapping operations generally employ a lapping table to finish flat surfaces of a workpiece. Lapping processes can be applied when a mirrored or high gloss finish is desired for a given workpiece. In this regard, lapping tables typically include a substantially planar abrasive disc capable of producing particularly smooth surface finishes. However, in general, lapping operations are not easily adapted to lapping non-planar surfaces. For example, cylindrical surfaces can be finished by other processes such as abrasive tape finishing or centerless grinding. Unfortunately, these known processes are not well suited for providing a mirrored or at least high gloss finish across a cylindrical surface. 
     Therefore, what is desired is an efficient and reliable way to apply a lapping operation to a non-planar surface. 
     SUMMARY 
     This paper describes various embodiments that relate to applying a lapping operation to a non-planar surface. 
     A method and apparatus for performing a lapping operation is disclosed. The method may include providing a lapping table comprising an abrasive disc defining a substantially planar abrasive surface. Further, the method may include rotating the abrasive disc about a first axis extending substantially perpendicularly to the substantially planar abrasive surface. Additionally, the method may include rotating a workpiece about a second axis such that a three-dimensional outer surface of the workpiece is in contact with the substantially planar abrasive surface of the abrasive disc, the second axis being non-parallel to the first axis. In this regard, outer, non-planar surfaces of objects may be subjected to lapping operations. For example, the workpiece may be a cylindrical workpiece. The method may also include rotating the workpiece about a third axis, the third axis extending substantially parallel to the first axis, to avoid issues with respect to portions of the workpiece being subjected to more abrasion. Each of the steps of the method may be performed concurrently. 
     Other aspects and advantages of the present disclosure will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1  illustrates a top view of a lapping table configured to perform a lapping operation on a workpiece defining a planar outer surface and including conditioning rings driven by a lip of an abrasive disc according to an example embodiment of the present disclosure; 
         FIG. 2  illustrates a perspective view of an alternate embodiment of a lapping table configured to perform a lapping operation on a workpiece defining a planar outer surface and including conditioning rings driven by a hub according to an example embodiment of the present disclosure; 
         FIG. 3  illustrates a top view of an alternate embodiment of a lapping table configured to perform a lapping operation on a workpiece defining a three-dimensional outer surface and including conditioning rings driven by a lip of an abrasive disc according to an example embodiment of the present disclosure; 
         FIG. 4  illustrates a perspective view of an alternate embodiment of a lapping table configured to perform a lapping operation on a workpiece defining a three-dimensional outer surface and including conditioning rings driven by a hub according to an example embodiment of the present disclosure; 
         FIG. 5  illustrates a side view of an alternate embodiment of a lapping table configured to perform a lapping operation on a workpiece defining a three-dimensional outer surface and including pressure applicators according to an example embodiment of the present disclosure; 
         FIG. 6  illustrates a perspective view of the lapping table of  FIG. 5  according to an example embodiment of the present disclosure; 
         FIG. 7  schematically illustrates a method for performing a lapping operation according to an example embodiment of the present disclosure; and 
         FIG. 8  schematically illustrates a block diagram of an electronic device according to an example embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Representative applications of methods and apparatus according to the present application are described in this section. These examples are being provided solely to add context and aid in the understanding of the described embodiments. It will thus be apparent to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the described embodiments. Other applications are possible, such that the following examples should not be taken as limiting. 
     In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments in accordance with the described embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the described embodiments, it is understood that these examples are not limiting; such that other embodiments may be used, and changes may be made without departing from the spirit and scope of the described embodiments. 
       FIG. 1  illustrates a top view of an embodiment of a lapping table  100 A. The lapping table  100 A may include an abrasive disc  102 . The abrasive disc  102  may define a substantially planar abrasive surface  104 . The abrasive disc  102  can be coupled to a rotational mechanism (e.g., a motor) configured to rotate the abrasive disc at various speeds about an axis (e.g., a central axis of the abrasive disc) extending substantially perpendicularly to the substantially planar abrasive surface  104 . The speed at which abrasive disc  102  rotates can be selected based on the type of surface finish that is desired from the lapping operation, amongst other factors. 
     The lapping table  100 A may additionally include one or more conditioning rings  106 . The conditioning rings  106  may include one or more attachment mechanisms for coupling one or more workpieces  108  (e.g., a component undergoing finishing) along an inside surface of the conditioning ring such that the workpieces are retained therein. In this regard, a center portion of the conditioning rings  106  may be hollow as illustrated, and the attachment mechanisms may engage the workpieces  108  such that workpieces are held therein. Alternatively, the conditioning rings  106  may comprise discs with cutouts therethrough configured to receive the workpieces therein. 
     In some embodiments the weight of the workpieces  108  may be great enough to produce sufficient force between the workpieces and the substantially planar surface  104  of the abrasive disc  102  to finish the workpieces to a desired extent. However, in other embodiments additional force may be applied to the workpieces  108  against the substantially planar surface  104  of the abrasive disc  102  to facilitate finishing the workpieces. For example, the workpieces  108  may be coupled to the conditioning rings  106  such that the weight of the conditioning rings presses the workpieces against the substantially planar abrasive surface  104  of the abrasive disc  102 . In another embodiment a pressure plate may press the workpieces against the substantially planar abrasive surface of the abrasive disc. 
     Regardless of the particular embodiment of the conditioning rings  106 , the workpieces  108  may be in contact with the substantially planar abrasive surface  104  of the abrasive disc  102 . However, the conditioning rings  106  may prevent the workpieces  108  from rotating with the abrasive disc  102  such that relative movement therebetween occurs in order to abrade a surface of the workpieces  108  in contact with the substantially planar abrasive surface  104  of the abrasive disc  102 . In this regard, linkages or support members  110  may be employed to hold the conditioning rings  106  in place such that relative movement between the conditioning rings and the abrasive disc  102 . For example, the support members  110  may include an outer attachment mechanism  112  that is stationary. Further, the support members  110  may include inner engagement mechanisms  114  that engage the conditioning rings  106  to prevent the conditioning rings from rotating with the abrasive disc  102 . 
     However, each of the conditioning rings  106  may rotate during operation of lapping table  100 A. In this regard, each of the conditioning rings  106  may rotate about a respective axis extending substantially parallel to the axis about which the abrasive disc  102  rotates. More particularly, the conditioning rings  106  may each rotate about a respective central axis thereof. The rotational speed of each of conditioning rings  106  can be configured as a function of a rotational speed of the abrasive disc  102 . For example, as illustrated in  FIG. 1 , in some embodiments an inner surface  116  of an outer lip  118  of the abrasive disc  102  can frictionally engage an outer periphery  120  of each of the conditioning rings  106  such that the conditioning rings are rotationally coupled therewith. Thereby, the abrasive disc  102  and the conditioning rings  106  may be mechanically coupled to one another such that a rotational speed of each conditioning ring is defined by a rotational speed of the outer lip  118  of the abrasive disc. Further, the support members  110  may allow rotation of each of the conditioning rings  106  by employing rollers as the inner engagement mechanisms  114 . 
       FIG. 2  illustrates a perspective view of an alternate embodiment of a lapping table  100 B. The lapping table  100 B of  FIG. 2  may be substantially similar to the lapping table  100 A of  FIG. 1  in a number of respects. In this regard, the lapping table  100 B may include the abrasive disc  102  defining the substantially planar abrasive surface  104 , one or more conditioning rings  106  configured to support workpieces  108  thereon. Note that support members (e.g., the above-described support members  110 ) may be employed in the lapping table  100 B to hold the conditioning rings  106  in place while allowing for rotation thereof. However, for clarity purposes, the support members are not shown in  FIG. 2 . 
     However,  FIG. 2  illustrates an alternative configuration for rotating the conditioning rings  106 . In this regard, as illustrated, the conditioning rings  106  can be engaged by a centrally positioned hub  122 . More particularly, an outer edge  124  of the hub  122  may engage the outer periphery  120  of each of the conditioning rings  106  such that the conditioning rings rotate about respective central axes thereof. In some embodiments the hub  122  may comprise a geared hub, which may be rotationally coupled to the abrasive disc  102  such that rotation of the abrasive disc  102  causes rotation of the hub  122 . Further, in some embodiments the hub  122  may be rotationally decoupled from the abrasive disc  102  and configured to rotate independently of the abrasive disc. Thereby, the conditioning rings  106  may be rotated at a number of rotational speeds, independent of a speed of the abrasive disc  102 . 
     Note that the lapping tables  100 A,  100 B described above are configured such that the conditioning rings  106  are actively rotated. More particularly, the outer periphery  120  of each of the conditioning rings  106  is contacted by either the outer lip  118  of the abrasive disc  102  (see,  FIG. 1 ) or a hub  122  (see, e.g.  FIG. 2 ) to impart rotational motion to the conditioning rings. However, the conditioning rings  106  may be rotated in various other manners within the scope of the present disclosure. 
     For example in another embodiment the conditioning rings  106  may be configured to passively rotate as a result of rotation of the abrasive disc  102 . In this regard, as the abrasive disc  102  passes underneath the conditioning rings  106 , portions of the conditioning rings farthest from the rotational axis of the abrasive disc are in contact with portions of the abrasive disc traveling at a greater speed than a speed of the abrasive disc in contact with portions of the conditioning rings closest to the center of the abrasive disc. Thus, by employing rollers at the inner engagement mechanisms  114  of the support members  110 , the conditioning rings  106  may tend to rotate as a result of the speed differential applied to inner and outer portions of the conditioning rings (relative to the rotational axis of the abrasive disc  102 ) by the abrasive disc. 
     The lapping tables  100 A,  100 B described above and illustrated in  FIGS. 1 and 2  are generally configured such that the abrasive disc  102  spins underneath the conditioning rings  106 , while the conditioning rings spin in place about respective central axes thereof. The conditioning rings  106  can be kept in place by support members (e.g., the support members  110 ). In this way, a bottom surface of each of the workpieces  108  can be exposed to varying portions of the substantially planar abrasive surface  104  of the abrasive disc  102 , thereby preventing any inconsistencies in the substantially planar abrasive surface of the abrasive disc from affecting a finish applied to the workpieces  108 . As can be readily appreciated the functionality of the above-described lapping tables  100 A,  100 B may be narrowly limited to lapping one substantially flat surface of a workpiece  108  in any given finishing operation. 
       FIG. 3  shows a top view of an alternate embodiment of a lapping table  200 A. The lapping table  200 A of  FIG. 3  may be substantially similar to the previously described lapping table  100 A illustrated in  FIG. 1  in a number of respects. In this regard, the lapping table  200 A may include an abrasive disc  202  defining a substantially planar abrasive surface  204 , one or more conditioning rings  206  configured to support workpieces  208  thereon. Support member  210  may prevent the conditioning rings  206  from rotating with the abrasive disc  202 . The support members  210  may include an outer attachment mechanism  212  that is stationary and one or more inner engagement mechanisms  214  (e.g., rollers) that engage the conditioning rings  206 . An inner surface  216  of an outer lip  218  of the abrasive disc  202  can frictionally engage an outer periphery  220  of each of the conditioning rings  206  such that the conditioning rings are rotationally coupled therewith and rotate about respective center axes thereof when the abrasive disc rotates. 
     Thus, as described above, the abrasive disc  202  can be coupled to a rotational mechanism (e.g., a motor) configured to rotate the abrasive disc at various speeds about an axis (e.g., a central axis of the abrasive disc) extending substantially perpendicularly to the substantially planar abrasive surface  204 . Further, a rotational mechanism (e.g., the conditioning rings) may be employed to rotate the workpieces  208  about axes extending substantially parallel to the axis about which the abrasive disc  202  rotates. For example, each of the conditioning rings  206  may rotate about a respective central axis thereof to rotate the workpieces  208  coupled thereto. 
     However, the lapping table  200 A illustrated in  FIG. 3  may differ from the previously-described lapping table  100 A of  FIG. 1  in that the lapping table  200 A may be configured to apply a lapping operation to a three-dimensional surface of a workpiece, rather than two-dimensional flat surface. Thus, by way of example, the lapping table  200 A may perform lapping operations on one or more cylindrical workpieces  208 , as illustrated. Note that although the lapping tables described hereinafter are generally referenced as being configured to perform lapping operations on cylinders, the lapping tables may be employed to perform lapping operations on workpieces defining various other shapes, such as a cone shape, in accordance with embodiments of the present disclosure. 
     In order to properly finish the entirety of the outer curved surface of the cylindrical workpieces  208 , each of the cylindrical workpieces may be respectively rotated about an axis such that a three-dimensional outer surface of each workpiece is in contact with the substantially planar abrasive surface  204  of the abrasive disc  202 . In this regard, the axis about which the workpieces are rotated may be non-parallel to the axis about which the abrasive disc  202  rotates. For example, as illustrated, the cylindrical workpieces  208  may be rotated about a central axis  224  thereof. In order to rotate the cylindrical workpieces  208  about the central axes  224  thereof, the lapping table  200 A may further comprise a rotational mechanism  226  rotationally coupled to each of the cylindrical workpieces  208 . For example, as illustrated, each rotational mechanism  226  may couple to opposing ends of, or extend through, one of the cylindrical workpieces  208 . Further, each rotational mechanism may be affixed to one of the conditioning rings  206 . Thus, for example, each rotational mechanism  226  may be affixed to one of the conditioning rings  206  at opposing ends of the cylindrical workpieces  208 . 
     Each conditioning ring  208  may receive one or more of the cylindrical workpieces  208 . For example, in the illustrated embodiment two of the conditioning rings  206  include one cylindrical workpiece  208  therein, whereas a third conditioning ring includes two cylindrical workpieces therein. In this regard, a bracket  228  may facilitate holding multiple cylindrical workpieces  208  in a conditioning ring  206 . Note that various other numbers of cylindrical workpieces may be received in the conditioning rings in other embodiments without departing from the scope of the present disclosure. 
     The rotational mechanisms  226  may include a rotary motor or other drive mechanism configured to rotate the cylindrical workpieces  208  about the about the respective central axes  224  thereof, as depicted in  FIG. 3 . In this way, the abrasive disc  202  can be utilized to apply a lapping operation around the entirety of the curved exterior surface of the cylindrical workpieces  208 . It should be noted that this operation can also be applied to workpieces having other non-planar geometries. This can be particularly applicable to a workpiece having a partially cylindrical surface, or to a workpiece having a substantially symmetric cross-section. 
       FIG. 4  illustrates a perspective view of an alternate embodiment of a lapping table  200 B. The lapping table  200 B of  FIG. 4  may be substantially similar to the lapping table  200 A of  FIG. 3  in a number of respects. In this regard, the lapping table  200 B may include the abrasive disc  202  defining the substantially planar abrasive surface  204 , and one or more conditioning rings  206 . The lapping table  200 B may further comprise the rotational mechanism  226  coupled to the cylindrical rings  206  and configured to rotate each of the cylindrical workpieces  208  about a respective central axis  224  of each cylindrical workpiece. Further, the bracket  228  may be configured to facilitate receipt of multiple cylindrical workpieces  208  in one of the conditioning rings  206 . Note that support members (e.g., the above-described support members  210 ) may be employed in the lapping table  200 B to hold the conditioning rings  206  in place while allowing for rotation thereof. However, for clarity purposes, the support members are not shown in  FIG. 4 . 
     However,  FIG. 4  illustrates an alternative configuration for rotating the conditioning rings  206 . In this regard, as illustrated, the conditioning rings  206  can be engaged by a centrally positioned hub  222 . More particularly, an outer edge  224  of the hub  222  may engage the outer periphery  220  of each of the conditioning rings  206  such that the conditioning rings rotate about respective central axes thereof. In some embodiments the hub  222  may comprise a geared hub, which may be rotationally coupled to the abrasive disc  202  such that rotation of the abrasive disc  202  causes rotation of the hub  222 . Further, in some embodiments the hub  222  may be rotationally decoupled from the abrasive disc  202  and configured to rotate independently of the abrasive disc. Thereby, the conditioning rings  206  may be rotated at a number of rotational speeds, independent of a speed of the abrasive disc  202 . 
     Note that the lapping tables  200 A,  200 B described above are configured such that the conditioning rings  206  are actively rotated. More particularly, the outer periphery  220  of each of the conditioning rings  206  is contacted by either the outer lip  218  of the abrasive disc  202  (see,  FIG. 3 ) or a hub  222  (see, e.g.  FIG. 4 ) to impart rotational motion to the conditioning rings. However, the conditioning rings  206  may be rotated in various other manners within the scope of the present disclosure. 
     For example in another embodiment the conditioning rings  206  may be configured to passively rotate as a result of rotation of the abrasive disc  202 . In this regard, as the abrasive disc  202  passes underneath the conditioning rings  206 , portions of the conditioning rings farthest from the rotational axis of the abrasive disc are in contact with portions of the abrasive disc traveling at a greater speed than a speed of the abrasive disc in contact with portions of the conditioning rings closest to the center of the abrasive disc. Thus, by employing rollers at the inner engagement mechanisms  214  of the support members  210 , the conditioning rings  206  may tend to rotate as a result of the speed differential applied to inner and outer portions of the conditioning rings (relative to the rotational axis of the abrasive disc  202 ) by the abrasive disc. 
     In the embodiments of the lapping tables  200 A,  200 B illustrated in  FIGS. 3 , and  4 , the workpieces  208  may be forced against the substantially planar abrasive surface  204  of the abrasive disc  202  by the weight of the workpieces. Further, the weight of the conditioning rings  206 , the rotational mechanisms  226 , and/or the bracket  228  may be applied to the workpieces  208  to force the workpieces against the substantially planar abrasive surface  204  of the abrasive disc  202 . Accordingly, the additional force applied to the workpieces  208  against the substantially planar surface  204  of the abrasive disc  202  may facilitate finishing the workpieces. 
     However, in other embodiments it may be preferable to actively press the workpieces  208  against the substantially planar surface  204  of the abrasive disc  202  or otherwise control the pressure applied by the cylindrical workpieces  208  against the abrasive disc. In this regard,  FIGS. 5 and 6  respectively illustrate side and perspective views of a lapping table  300  according to an additional embodiment of the present disclosure. The lapping table  300  may include an abrasive disc  302  defining a substantially planar abrasive surface  304 , which may be similar to the abrasive discs described above and configured to finish cylindrical workpieces  306 . 
     In this embodiment one or more pressure applicators  308  may be configured to respectively engage one or more of the cylindrical workpieces  306 . The pressure applicators  308  may be configured to engage end surfaces of the cylindrical workpieces  306  to hold the cylindrical workpieces in a desired position. Thus, as illustrated, the pressure applicators  308  may hold the cylindrical workpieces  306  such that curved outer surfaces thereof are in contact with the substantially planar abrasive surface  304  of the abrasive disc  302   
     As depicted, the pressure applicators  308  may include a rotational mechanism  310  (e.g. a motor) configured to rotate each of the cylindrical workpieces  306  about a central axis  312  thereof. Accordingly, the entirety of the curved outer surface of the cylindrical workpieces  306  may undergo the lapping operation. The pressure applicators  308  may also include a rotational mechanism  314  (e.g., a motor) configured to spin about an axis  316  substantially normal to the substantially planar abrasive surface  304  of the abrasive disc  302 . Rotation about the axis  316  substantially perpendicular to the substantially planar abrasive surface  304  of the abrasive disc  302  may be configured to function in the same manner as rotation of the above-described conditioning rings. More particularly, rotation about the axis  316  may be configured to ensure that finishing of the cylindrical workpieces  306  is conducted evenly. In this regard, without rotation of the workpieces  306  about the axis  316 , portions of the workpiece closer to an outer edge of the abrasive disc  302  may undergo a greater degree of finishing than portions of the abrasive disc closer to rotational center of the abrasive disc. 
     Thus, as described above, the lapping table  300  may perform lapping operations in a manner similar to the manner described above with respect to the lapping tables  200 A,  200 B illustrated in  FIGS. 3 and 4 . In this regard, the abrasive disc  302  can be coupled to a rotational mechanism  318  (e.g., a motor) configured to rotate the abrasive disc at various speeds about an axis (e.g., a central axis  320  of the abrasive disc) extending substantially perpendicularly to the substantially planar abrasive surface  304 . Further, the rotational mechanism  314  may be employed to rotate the workpieces  306  about axes  316  extending substantially parallel to the axis  320  about which the abrasive disc  302  rotates. Additionally, In order to properly finish the entirety of the outer curved surface of the cylindrical workpieces  306 , each of the cylindrical workpieces may be respectively rotated by a rotational mechanism  310  about an axis  312  such that a three-dimensional outer surface of each workpiece is in contact with the substantially planar abrasive surface  304  of the abrasive disc  302 . In this regard, the axis  312  about which the workpieces  306  are rotated may be non-parallel to the axis  320  about which the abrasive disc  302  rotates. 
     However, the lapping table  300  may provide additional functionality. In this regard, the pressure applicators  308  may be configured to apply pressure to the cylindrical workpieces  306  such that the workpieces are forced into contact with the substantially planar abrasive surface  304  of the abrasive disc  302 . Accordingly, by applying pressure to the cylindrical workpieces  306  in this manner, finishing thereof may be facilitated. Further, the pressure applicators  308  may be configured to apply a variable amount of pressure between cylindrical workpieces  306  and the substantially planar abrasive surface  304  of the abrasive disc  302 . In this regard, by way of example, the pressure applicators  308  may include actuators  322  (e.g., hydraulic or pneumatic actuators) configured to press the cylindrical workpieces  306  against the substantially planar abrasive surface  304  of the abrasive disc  302  with a selectable degree of pressure. 
     A controller  324  may be configured to control each of the parameters of the lapping table  300 . In this regard, the controller  324  may be in communication with the pressure applicators  308  to control the amount of pressure applied to the cylindrical workpieces  306  by the actuators  322  and the rotational speed and direction about the axes  312 ,  316  as caused by the rotational mechanisms  310 ,  314 . Further, the controller  324  may be communication with the rotational mechanism  318  configured to rotate the abrasive disc  302  control the speed and/or direction of rotation thereof. Accordingly, the controller  324  may control various finishing parameters during a lapping operation to produce a desired surface finish on the cylindrical workpieces  306 . 
     Note that each of the embodiments of lapping tables described herein may include a controller configured to control lapping operations. In this regard, a controller substantially similar to the controller  324  illustrated in  FIGS. 5 and 6  may be employed in each of the embodiments of lapping tables. In this regard, the controller may control each of the above described rotational movements and/or control of pressure applied to workpieces against the substantially planar abrasive surface of an abrasive disc. 
     Further, note that each of the rotational motions disclosed herein may be controlled (e.g., with the controller) to define desired rotational speeds. In this regard, in some embodiments the rotational speeds may be independently controlled. For example, in embodiments of the disclosure discussed above, an abrasive disc may be rotated about a first axis extending substantially perpendicularly to a substantially planar abrasive surface. Further, a workpiece may be rotated about a second axis that is non-parallel to the first axis (e.g., perpendicular thereto). Additionally, the workpiece may be rotated about a third axis, which may be substantially parallel to the first axis. More particularly, the controller can be configured to rotate the workpiece about the third axis in a first direction or a second direction opposite the first direction. In some embodiments the controller can be configured to change a direction and/or speed of rotation of the workpiece during a machining operation. In other embodiments, the workpiece can be configured to rotate freely about the third axis. Accordingly, the rotational speed of each of these rotational movements may be controlled (e.g., independently controlled) to define a desired surface finish on the workpiece and/or meet other desirable manufacturing parameters. 
       FIG. 7  illustrates a block diagram of a method for performing a lapping operation. As illustrated, the method may include providing a lapping table comprising an abrasive disc defining a substantially planar abrasive surface at operation  402 . Further, the method may include rotating the abrasive disc about a first axis extending substantially perpendicularly to the substantially planar abrasive surface at operation  404 . Additionally, the method may include rotating a workpiece about a second axis such that a three-dimensional outer surface of the workpiece is in contact with the substantially planar abrasive surface of the abrasive disc, the second axis being non-parallel to the first axis at operation  406 . 
     In some embodiments the workpiece may comprise a cylindrical workpiece and the second axis may extend between first and second end surfaces of the cylindrical workpiece. Further, rotating the workpiece about the second axis at operation  406  may comprise engaging the end surfaces of the cylindrical workpiece. The method may additionally include rotating the workpiece about a third axis, the third axis extending substantially parallel to the first axis. The third axis may be offset by a non-zero distance from the first axis. Rotating the abrasive disc about the first axis, rotating the workpiece about the second axis, and rotating the workpiece about the third axis may be conducted concurrently. The method may additionally include pressing the workpiece against the substantially planar abrasive surface of the abrasive disc. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     In this regard,  FIG. 8  is a block diagram of an electronic device  500  suitable for use with the described embodiments. In one example embodiment the electronic device  500  may be embodied in or as a controller configured for controlling lapping operations as disclosed herein. In this regard, the electronic device  500  may be configured to control or execute the above-described lapping operations performed by the above-described lapping tables  100 A,  100 B,  200 A,  200 B,  300 . In this regard, the electronic device  500  may be embodied in or as the above-described controller. 
     The electronic device  500  illustrates circuitry of a representative computing device. The electronic device  500  may include a processor  502  that may be microprocessor or controller for controlling the overall operation of the electronic device  500 . In one embodiment the processor  502  may be particularly configured to perform the functions described herein relating to lapping operations. The electronic device  500  may also include a memory device  504 . The memory device  504  may include non-transitory and tangible memory that may be, for example, volatile and/or non-volatile memory. The memory device  504  may be configured to store information, data, files, applications, instructions or the like. For example, the memory device  504  could be configured to buffer input data for processing by the processor  502 . Additionally or alternatively, the memory device  504  may be configured to store instructions for execution by the processor  502 . 
     The electronic device  500  may also include a user interface  506  that allows a user of the electronic device  500  to interact with the electronic device. For example, the user interface  506  can take a variety of forms, such as a button, keypad, dial, touch screen, audio input interface, visual/image capture input interface, input in the form of sensor data, etc. Still further, the user interface  506  may be configured to output information to the user through a display, speaker, or other output device. A communication interface  508  may provide for transmitting and receiving data through, for example, a wired or wireless network such as a local area network (LAN), a metropolitan area network (MAN), and/or a wide area network (WAN), for example, the Internet. 
     The electronic device  500  may also include a lapping module  510 . The processor  502  may be embodied as, include or otherwise control the finishing module  510 . The lapping module  510  may be configured for controlling or executing the lapping operations and associated operations as discussed herein. 
     In this regard, for example, in one embodiment a computer program product comprising at least one computer-readable storage medium having computer-executable program code portions stored therein is provided. The computer-executable program code portions, which may be stored in the memory device  504 , may include program code instructions for performing the lapping operations and associated operations disclosed herein. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20140220
Publication Date: 20170207
Grant Date: 20170207
Priority Date: 20130607
Inventors: LANCASTER-LAROCQUE SIMON REGIS LOUIS
CHAN COLLIN D.
Assignee: APPLE INC
CPC Classifications: [{"code": "B24B5/042", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B37/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B5/047", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B37/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "B24B5/045", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B37/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "B24B37/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B5/045", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B5/042", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B5/047", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 52005829