Abstract:
A robotic turntable includes a first rotating table, a second rotating table, and a workpiece table. A motor rotates the first rotating table. The second rotating table is coaxial with the first rotating table and rotationally positionable relative to the first rotating table. The workpiece table is rotationally fixed with respect to the second rotating table and is tiltably positionable with respect to the second rotating table. A first actuator cooperates with the second table to change the rotational position of the second table with respect to the first table. A second actuator cooperates with a lever attached to the first table to change the tilt of the workpiece table. Changes to rotation and tilt are obtained solely by the positions of the actuators and rotation of the first table by the motor.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to turntables and in particular to a robotic turntable for presenting various aspects of an object for scanning. 
   Various small objects are used as models for molding shaped articles. For example, ear canal moldings are made to manufacture in-the-ear hearing aids, and tooth molds are made for manufacturing crowns. Modern equipment enables scanning of moldings to generate numerical models of the shapes of moldings, and the numerical models may be used to control equipment which manufactures the final product. Known equipment for scanning moldings is expensive, and the costs are prohibitive for placement of scanning machines at dental or medical offices. As a result, moldings are mailed, resulting in mailing costs and delays in providing a product. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention addresses the above and other needs by providing a novel robotic turntable suitable for use in individual medical and dental offices. The robotic turntable includes a first rotating table, a second rotating table, and a workpiece table. A motor rotates the first rotating table. The second rotating table is coaxial with the first rotating table and rotationally positionable relative to the first rotating table. The workpiece table is rotationally fixed with respect to the second rotating table and is tiltably positionable with respect to the second rotating table. A first actuator cooperates with the second table to change the rotational position of the second table with respect to the first table. A second actuator cooperates with a lever attached to the first table to change the tilt of the workpiece table. Changes to rotation and tilt are obtained solely by the positions of the actuators and rotation of the first table by the motor. 
   In accordance with one aspect of the invention, there is provided a robotic turntable comprising a motor, a first table rotationally driven by the motor, and a workpiece table rotationally coupled to the first table and tiltable with respect to the first table. A first actuator has a free position and a stop position. In the free position, the workpiece table rotates with the first table, and in the stop position, a rotation of the first table is coupled to a change in the rotational position of the workpiece table with respect to the first table. A second actuator has a second free position and a second stop position. In the second stop position, the rotation of the first table is coupled to a change in tilt of the workpiece table. 
   In accordance with another aspect of the invention, there is provided a method for controlling a workpiece table. The method includes aligning a workpiece table supporting a workpiece with a first table and rotating the first table to scan a workpiece. After scanning the vertically aligned workpiece, the rotation of the first table is stopped and a second actuator arm is aligned with a spindle lever. The first table is rotated to pivot the spindle lever, thereby causing a spindle attached to the workpiece table to tilt and thereby the workpiece table to tilt. After moving the second actuator arm out of alignment with the spindle lever, the first table is again rotated thereby rotating the tilted workpiece table to obtain a scan of the tilted workpiece. The method may further include stopping the rotation of the first table and aligning a first actuator arm with an actuator notch. The first table is then rotated to create a new rotational relationship between the first table and the tilted workpiece table, wherein a new face of the workpiece is caused to tilt downward. The first actuator arm is moved out of alignment with the actuator notch and the first table again rotated thereby rotating the tilted workpiece table with a different view of the workpiece. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
       FIG. 1A  is a side view of a robotic turntable according to the present invention. 
       FIG. 1B  is a top view of the robotic turntable according to the present invention. 
       FIG. 1C  is a system including a sensor and a Personal Computer (PC) cooperating with the robotic turntable. 
       FIG. 2  depicts a workpiece suitable for use with the present invention. 
       FIG. 2A  depicts the workpiece tilted with a face “A” tilted down. 
       FIG. 2B  depicts the workpiece tilted with a face “A” tilted down and rotated 90 degrees clockwise from  FIG. 2A . 
       FIG. 2C  depicts the workpiece tilted with a face “A” tilted down and rotated 180 degrees clockwise from  FIG. 2A . 
       FIG. 2D  depicts the workpiece tilted with a face “A” tilted down and rotated 270 degrees clockwise from  FIG. 2A . 
       FIG. 3A  shows the workpiece tilted with a face “B” tilted down. 
       FIG. 3B  depicts the workpiece tilted with a face “B” tilted down and rotated 90 degrees clockwise from  FIG. 3A . 
       FIG. 3C  depicts the workpiece tilted with a face “B” tilted down and rotated 180 degrees clockwise from  FIG. 3A . 
       FIG. 3D  depicts the workpiece tilted with a face “B” tilted down and rotated 270 degrees clockwise from  FIG. 3A . 
       FIG. 4  shows the geometric alignment of a first table, second table, and workpiece table before rotations or tilts. 
       FIG. 5  shows the geometric alignment of the first table, the second table, and the workpiece table after rotating the second table with respect to the first table. 
       FIG. 6  shows the geometric alignment of the first table, the second table, and the workpiece table after rotating the second table with respect to the first table and tilting the workpiece table with respect to the first table and the second table. 
       FIG. 7  shows the geometric alignment of the first table, the second table, and the workpiece table after rotating the second table with respect to the first table and tilting the workpiece table with respect to the first table and the second table and rotating the first table. 
       FIG. 8  shows the geometric alignment of the first table, the second table, and the workpiece table after tilting the workpiece table with respect to the first table and the second table without any rotations. 
       FIG. 9  shows the geometric alignment of the first table, the second table, and the workpiece table after tilting the workpiece table with respect to the first table and the second table and rotating the first table. 
       FIG. 10  shows the geometric alignment of the first table, the second table, and the workpiece table after tilting the workpiece table with respect to the first table and the second table and rotating the first table and then rotating the second table with respect to the first table. 
       FIG. 11  is a base plate of the first table with a spindle lever pivotally attached and with the spindle lever in a first position. 
       FIG. 12A  is the base plate of the first table with a spindle guide over the spindle lever. 
       FIG. 12B  is the base plate of the first table with the spindle guide over the spindle lever and with the spindle lever in a second position. 
       FIG. 13A  shows the base plate rotated and a second actuator with a second actuator arm positioned to cooperate with the spindle lever. 
       FIG. 13B  shows the base plate with the spindle lever pushed to the second position by the rotation of the base plate. 
       FIG. 14  shows an upper plate attached to the base plate. 
       FIG. 15  is a second table according to the present invention. 
       FIG. 16  is a cross-sectional view of the second table taken along line  16 - 16  of  FIG. 15 . 
       FIG. 17A  shows a workpiece table attached to the second table which is attached to the first table. 
       FIG. 17B  shows the workpiece table attached to the second table which is attached to the first table with the second table and work piece rotated 90 degrees counter clockwise. 
       FIG. 17C  shows the workpiece table attached to the second table which is attached to the first table with the second table and work piece rotated 180 degrees counter clockwise. 
       FIG. 17D  shows the workpiece table attached to the second table which is attached to the first table with the second table and work piece rotated 270 degrees counter clockwise. 
       FIG. 18  shows the workpiece table attached to the second table which is attached to the first table and a first actuator and first actuator arm. 
       FIG. 19A  depicts the second actuator arm positioned to cooperate with an actuator notch on the second table. 
       FIG. 19B  depicts the cooperation of the second actuator arm with the actuator notch on the second table. 
       FIG. 19C  depicts further cooperation of the second actuator arm with the actuator notch on the second table. 
       FIG. 20  describes a method according to the present invention. 
   

   Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
   A side view of a robotic turntable  10  according to the present invention is shown in  FIG. 1A , and a top view of the robotic turntable  10  is shown in  FIG. 1B . The turntable  10  includes a base  11  with a motor  18 , actuators  22  and  28 , and a rotating table assembly  17 . The motor  18  is preferably controllable in a way that permits programmable and precise motion, and is controllable in speed, direction of rotation, and shaft angular position, and is more preferably a stepping motor, an AC servo motor, or a DC servo motor, and is most preferably a DC Servo motor with an incremental encoder attached to the motor back shaft. Alternatively, with proper feedback, an air motor, hydraulic motor and the like may be used. 
   The motor  18  is supported by a motor support  18   a . A belt  20  connects the motor  18  to the rotating table assembly  17 . The belt  20  may be a timing belt, gear drive, chain drive or similar reliable method of transmitting the exact motion of the motor shaft to the rotating table assembly  17 , and is preferably a toothed belt to help maintain the timing between the motor  18  and the rotating table assembly  17 . 
   The actuators  22 ,  24  may be solenoid actuators, air driven actuators, or hydraulic actuators, and are preferable solenoid actuators, and more preferably 12 volt solenoid actuators. The first actuator  22  includes a first actuator arm  24 , and the second actuator  28  includes a second actuator arm  30 . The motor  18 , the first actuator  22 , and the second actuator  28  are preferably jointly computer controlled to coordinate the rotation of the rotating table assembly  17  with the actuation of the first actuator  22  and the second actuator  28  to obtain the desired behavior as described below. A home position detector comprising elements  37  and  37   a  initialized the position of the turn table assembly at start-up. The home position detector is preferably a hall effect device, an optical switch, or micro switch, and is more preferably a hall effects sensor  37  and magnet  37   a  which allow an initial motor/table timing to be established. 
   The rotating table assembly  17  includes a first table  12 , a second table  14 , and a workpiece table  16 . A spindle  34  is rotationally fixed to the workpiece table  16  and is supported at a table end  34   a  by spindle supports  36 . As described below in  FIG. 15A , the spindle supports  36  are preferably flat springs  76 . However, the spindle supports  36  may be any support structure which constrains the workpiece table  16  to rotate with the second table  14 , but allows the workpiece table  16  to tilt with respect to the second table  14 . For example, the spindle supports  36  may be a solid structure with a keyed ball and socket to allow the spindle to tilt but not freely rotate. A rotating table assembly with any spindle support which rotationally fixes the spindle while allowing the spindle to tilt is intended to come within the scope of the present invention. 
   The second table  14  includes an actuator notch  26  for cooperation with the first actuator arm  24 , and the first table  12  includes a spindle lever  32  for cooperation with the second actuator arm  30 . The actuators  22  and  28  raise the respective arms  24  and  30  to obtain the cooperation of the arms  24  and  30  with the notch  26  and lever  32 . 
   The robotic turntable  10  may be programably controlled using a robotic controller comprising an electrical (e.g., a computer), or a mechanical controller (e.g., using cams, levers, hydraulics and/or pneumatics,) is preferably controlled using a computer, and is more preferably controlled using a Personal Computer (PC). A sensor  13  and a PC  39  are shown in  FIG. 1C  cooperating with the robotic turntable  10 . The sensor  13  directs a sensor beam  13   a  onto the workpiece  38  to generate a digital representation of the workpiece  38 . The PC  39  is connected by cables  39   a  to the sensor  13  and the robotic turntable  10 . The sensor  13  may be, for example, a laser sensor. 
   The PC  39  includes a micro-processor, memory, other elements of known personal computers, and a controller (although the controller may also reside outside the PC  39 ). The PC  39  programs the controller to control the robotic turntable  10 . A controller program may be stored in the PC  39  and loaded into the controller as needed or the controller program may be stored in RAM on the controller card. The motor  18  provides encoder signals to the controller, and the controller includes interfaces for the encoder signals that detect signal errors. For example, the interface may look for a missing signal. Encoder signals generally comprise pairs of up and down pulses. If one pulse is missing, the interface sets an alarm. If a duty cycle of the pulses falls outside an expected range, an alarm may also be set. The controller further includes a set of software counters which increment or decrement according to the incoming encoder signals. Regardless of whether or not power is being provided to the motor  18 , the counters continue to maintain a total representing the position of a motor shaft of the motor  18 , thereby avoiding errors in motor shaft position due to outside influences that might force the motor shaft out of an intended position. A power supply in the PC  39  provides power to drive the motor  18  in both directions with a signal voltage output from 0 volts to approximately +−10 Volts. This power signal is passed to an amplifier to provide motor power in proportion to the signal voltage. 
   The robotic controller receives instructions from a computer program to rotate the motor shaft in the form of total encoder counts to define the size of the rotation and encoder counts per second to define angular velocity. Angular acceleration and angular deceleration are similarly defined. When the robotic controller executes a rotation, it first calculates a trajectory based on the angular speed and duration of the move. Then it begins to apply a power level to the motor  18  which rotates the motor shaft in the desired direction. The angular position of the motor shaft is monitored by observing the encoder counts several thousand times a second. The angular position of the motor shaft is compared with the theoretical trajectory and the error is converted to a power change to the motor  18 , in the direction that will correct the error. 
   The robotic controller has the ability to turn off or on a number of signal outputs at points in time or according to pre-defined conditions, thereby controlling the actuators  22 ,  28 . A complicated string of instructions to rotate the motor shaft, stop the motor shaft, operate an actuator  22  or  28  and rotate the motor shaft again are assembled to achieve the desired motions of the workpiece  38 . 
   A workpiece  38  suitable for use with the robotic turntable  10  is shown residing vertically in  FIG. 2 . The workpiece  38  includes faces A, B, C (on a back side), and D. The workpiece  38  may be fixed to the workpiece table  16  and is aligned with a third coordinate system (X 3 , Y 3 , Z 3 ) of the workpiece table  16 . The coordinate systems are described in detail in  FIGS. 4-10 . The present invention allows the workpiece  38  to be rotated for scanning or for any other process benefitting from the positioning provided by the present invention. The workpiece  38  may be rotated while in the vertical position about the axis of rotation  40  as indicated by vertical workpiece rotation  42 . The axis of rotation  40  does not tilt with respect to the second table  14 . 
   In many instances, a simple single axis rotation as depicted in  FIG. 2  is not adequate to provide sufficient views of the workpiece  38 . This inadequacy may be addressed by tilting and rotating the workpiece  38  as depicted in  FIGS. 2A ,  2 B,  2 C, and  2 D. The workpiece  38  is shown tilted with a face “A” tilted down in  FIG. 2A . The workpiece  38  is rotated about the axis of rotation  40  and in each position shown in  FIGS. 2A-2D , the face A remains down. 
   The workpiece  38  is depicted in  FIGS. 3A ,  3 B,  3 C, and  3 D tilted and rotated with the face “B” tilted down. The workpiece  38  may further be tilted with faces C and/or D down, and rotated about the axis of rotation  40 . Note that the axis of rotation  40  remains fixed, regardless of the tilt of the workpiece  38 . 
   The alignment of the first table  12 , the second table  14 , and the workpiece table  16  before any rotations or tilts is shown in  FIG. 4 . The first table  12  is geometrically described by coordinate system X 1 , Y 1 , Z 1 . The second table  14  is geometrically described by the coordinate system X 2 , Y 2 , and Z 2 . The workpiece table  16  is geometrically described by the coordinate system X 3 , Y 3 , and Z 3 . The axis of rotation  40  is aligned with the Z 1  axis. 
   The alignment of the first table  12 , the second table  14 , and the workpiece table  16 , after rotating the second table  14  with respect to the first table  12  by an angle Θ 1 , is shown in  FIG. 5 . The second table  14  is geometrically described by the axes X 2 ′, Y 2 ′ and Z 2 , and the workpiece table  16  is geometrically described by the axes X 3 ′, Y 3 ′, and Z 3 . The workpiece table  16  is constrained to rotate with the second table  14 . The Z 1 , Z 2 , and Z 3  axes remain unchanged and aligned. 
   The alignment of the first table  12 , the second table  14 , and the workpiece table  16  after rotating the second table  14  by the angle Θ 1  with respect to the first table  12  (as seen in  FIG. 5 ), and after tilting the workpiece table  16  by an angle φ 1  with respect to the first table  12  and the second table  14 , is shown in  FIG. 6 . The axis of rotation  40  remains fixed and aligned with the original Z 1  axis. The tilted workpiece table  16  (and therefore the tilted workpiece  38 ) axis Z 3 ″ is aligned to a spindle axis  35  which intersects the X 1  axis of the first table  12 . The spindle axis  35  intersects the first table  12  along the X 1  axis regardless of the rotation of the second table  14 , or of the tilt of the workpiece table  16 . 
   The geometries depicted in  FIG. 6  are shown after an additional rotation of Θ 2  of the first table  12  in  FIG. 7 . The relative rotation of the second table  14  with respect to the first table  12  is unchanged, and the tilt of the workpiece table  16  with respect to the second table  14  is unchanged. For example, the change from  FIG. 6  to  FIG. 7  is representative of the basic rotation of the rotating table assembly  17  while the workpiece  38  is being scanned. The same face of the workpiece  38  (i.e., the face aligned with the Y 3 ″ axis) is leaning downward in both  FIGS. 6 and 7 . The rotation Θ 2  is representative of rotations occurring during scanning a workpiece. 
   The alignment of the first table  12 , the second table  14 , and the workpiece table  16  after tilting the workpiece table  16  by φ 1  with respect to the first table  12  and the second table  16  without any rotations, is shown in  FIG. 8 . It is thus shown that the operation of tilting the workpiece table  16  is independent of the rotation of the rotating table assembly  17 , and of the rotation of the second table  14  with respect to the first table  12 . Note however, the face of the workpiece  38  being tilted downward does depend on the rotation of the second table  14  with respect to the first table  12 . In  FIG. 8 , the face opposite the X 3 ′ axis is tilted downward. In  FIG. 6  (after rotation of the second table with respect to the first table) the face aligned with the Y 3 ″ axis is tilted downward. 
   The alignment of the first table  12 , the second table  14 , and the tilted workpiece table  16  of  FIG. 8  after rotating the rotating table assembly  17  by Θ 3  is shown in  FIG. 9 . The face of the workpiece  38  approximately aligned opposite to the X 3 ′ axis is tilting down, as in  FIG. 8 . 
   The alignment of the first table  12 , the second table  14 , and the tilted workpiece table  16  of  FIG. 9 , after rotating the second workpiece table  14  by Θ 4  with respect to the first table  12 , is shown in  FIG. 10 . The rotation of the second table  14  relative to the first table  12 , with no change in the tilt of the workpiece table  16 , results in a change in the downward facing face of the workpiece  38 . The face approximately aligned with axis x 3 ′ is now the downward tilting face. 
   A base plate  48  of the first table  12  with the spindle lever  32  pivotally attached is shown in  FIG. 11 . Three blocks  50   a ,  50   b , and  50   c  reside on the base plate  48  and provide support and mounting for an upper plate  68  (see  FIG. 14 ). A spindle bed  56  is formed in the based plate  48  to accommodate a lever (or moving) end  34   b  of the spindle  34  (see  FIG. 1A ). The spindle lever  32  includes a first spindle slot  58  for cooperating with the lever end  34   b  of the spindle  34 . A magnet  54  is carried by the lever  32 , and cooperates with stops  52   a  and  52   b  to provide a first position (at stop  52   a ) and a second position (at stop  52   b ). 
   The base plate  48  of the first table  12  with a spindle guide  60  residing over the spindle lever  32  and with the spindle lever  32  in the first position is shown in  FIG. 12A . The spindle guide  60  includes a second spindle slot  62 , and an assembly feature  64 . The second spindle slot  62  is skewed (i.e., is not aligned) with respect to the first spindle slot  58 , wherein the intersection of the spindle slots  58  and  62  create a unique position for the lever end  34   b  of the spindle  34 . The base plate  48  with the spindle lever  32  in the second position is shown in  FIG. 12B . The first position of the spindle lever  32  results in the spindle axis  34  residing in a tilted position as shown in  FIG. 8 , and the second position of the spindle lever  32  results in the spindle axis  34  residing in a vertical position as shown in  FIG. 4 . The second spindle groove  62  thus corresponds to the X 1  axis in  FIGS. 4-10 . 
   The spindle lever  32  cooperates with the second actuator arm  30  to move the spindle lever  32  between the first position and the second position. The first table  12  may be rotated in the direction Θ 5  while the second actuator arm  30  is aligned with the spindle lever  32  to block the rotation of the spindle lever  32 . Thus blocked from rotating, the spindle lever  32  moves from the first position to the second position (relative to the base plate  48 ) as shown in  FIG. 13B . The motor  18  (see  FIGS. 1A and 1B ) is controlled to rotate the rotating table assembly  17  to position the magnet  54  sufficiently close to the stop  52   b , wherein magnetic attraction between the magnet  54  and the stop  52   b  pulls the spindle lever  32  into the second position. The spindle  34  is vertical when the spindle lever  32  is in the second position. 
   The spindle lever  32  may be moved from the second position to the first position by the reverse of the actions described in  FIGS. 13A and 13B , wherein the actuator arm  30  is positioned to intercept the spindle lever  32  on the side opposite that depicted in  FIGS. 13A and 13B , and the motor  18  rotates the base plate  48  opposite the direction Θ 6  to move the spindle lever from the second position to the first position. The spindle  34  is tilted when the spindle lever  32  is in the first position. 
   An upper plate  68  is shown attached to the base plate  48  in  FIG. 14 . The upper plate  68  resides on the blocks  50   a ,  50   b , and  50   c  (see  FIG. 11 ), and includes rollers  72 , spindle passage  74 , and detent  70 . The rollers  72  cooperate with the second table  14  to provide rotation to the second table  14  with respect to the first table  12 . There are preferably three rollers  72 . The spindle passage  74  allows the spindle  34  to pass through the upper plate  68  and to move between the vertical and the tilted position. The detent  70  is preferably a spring loaded ball protruding from the upper plate  68 , which detent  70  cooperates with the second table  14  to provide angular indexing for the second table  14  with respect to the first table  12 . The detent  70  is preferably biased upward by a leaf spring attached to a bottom surface of the upper plate  68 . 
   The second table  14  is shown separate from the rotating table assembly  17  in  FIG. 15 . The perimeter of the second turntable  14  includes the actuator notch  26  for cooperation with the first actuator  22  (see  FIGS. 1A and 1B ). The interior of the second turntable  14  is circular. 
   A cross-sectional view of the second table  14  taken along line  16 - 16  of  FIG. 15  is shown with a cooperating roller  72  in  FIG. 16 . Preferably, three concave rollers  72  (see  FIG. 14 ) cooperate with a convex inner edge  14   a  of the second table  14  to rotatably position the second table  14  with respect to the first table  12 . A bottom surface  14   b  of the second table  14  includes indentations  78  for cooperation with the detent  70  (see  FIG. 14 ) to index the second table  14  with respect to the first table  12 . There are preferably two to six spaced apart indentations  78  on the second table  14 , and more preferably four approximately evenly spaced indentations  78 . The rotational cooperation between the second table  14  and the first table  12  may include frictional elements instead of the detent and indentations described herein. 
   The workpiece table  16  is shown in  FIG. 17A  attached to the second table  14  by spindle supports comprising flat springs  76 . The flat springs  76  form an “X” above the second table  14  and support the workpiece table  16  while allowing the workpiece table  16  to tilt but not rotate with respect to the second table  14 . The flat springs  76  preferably are in the form of an inverted “U”. The second table  14  is rotatably held by the rollers  72  (also see  FIGS. 14 and 16 ) which are attached to the upper plate  68  of the first table  12 . 
   The second table  14  is shown rotated 90 degrees counter clockwise with respect to the first table  12  in  FIG. 15B , rotated 180 degrees counter clockwise in  FIG. 15C , and rotated 270 degrees counter clockwise in  FIG. 15D . 
   The rotating table assembly  17  is shown with the first actuator  22  and first actuator arm  24  in  FIG. 18 . While scanning, the first actuator arm is moved (or dropped) out of the way of the actuator notch  26  to allow free rotation of the rotating table assembly  17 . 
   The second actuator arm  44  positioned to cooperate with the actuator notch  26  (see  FIG. 18 ) of the second table  14  is shown in  FIG. 19A . The rotating table assembly  17  (see  FIG. 1A ) is rotated by Θ 7  with respect to  FIG. 18 , and the actuator notch  26  has been brought into contact with the first actuator arm  24 . 
   The cooperation of the second actuator arm  24  with the actuator notch  26  resulting in the rotation of the second table  14  with respect to the first table  12  is depicted in  FIG. 19B . The first table  12  rotates through an angle Θ 8  and the actuator arm  24  blocks the rotation of the second table  14 . 
   The further cooperation of the first actuator arm  24  with the actuator notch  26  on the second table  14  is shown in  FIG. 19C . The first table  12  is rotated by Θ 9  to the next indexing point while the second table  14  has been held by the first actuator arm  24 . 
   A method according to the present invention for rotating a workpiece is described in  FIG. 20 . The method includes aligning a workpiece table supporting a workpiece with a first table at step  100  and rotating the first table thereby rotating the workpiece table to scan a workpiece at step  102 . After scanning the vertically aligned workpiece, the rotation of the first table is stopped at step  104 , and a second actuator arm is aligned with a spindle lever at step  106 . The first table is rotated to pivot the spindle lever at step  108 , thereby causing a spindle attached to the workpiece table to tilt and the workpiece table to tilt. After moving the second actuator arm out of alignment with the spindle lever at step  110 , the first table is again rotated thereby rotating the tilted workpiece table to obtain a scan of the tilted workpiece at step  112 . The method may further include stopping the rotation of the first table at step  114  and aligning a first actuator arm with an actuator notch at step  116 . The first table is then rotated at step  118  to create a new rotational relationship between the first table and the tilted workpiece table. The first actuator arm is moved out of alignment with the actuator notch at step  120  and the first table again rotated at step  122  thereby rotating the tilted workpiece table with a different view of the workpiece. 
   While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.