Patent Description:
For instance, consider a machined tapered roller bearing <NUM> like the one shown in <FIG>. When assembled, the tapered roller bearing <NUM> has tapered rolling elements <NUM> held by a cage <NUM> between an outer ring <NUM>, also called a cup or outer race, and an inner ring <NUM>, also called a cone or inner race. To perform the precision grinding operations needed to manufacture the cone <NUM> of this tapered roller bearing <NUM>, three separate grinding machines are required: one to grind the inside/inner diameter (ID), one to grind the outside/outer diameter (OD), and one to grind the rib. Similarly, three separate machines are used for precision grinding of fuel injectors for internal combustion engines: one to grind the inlet bore, one to grind the check valve seat, and one to grind the outlet bore. <CIT> discloses a system for performing multiple manufacturing steps.

The invention is defined in the independent claims <NUM> and <NUM> respectively. An inventive precision positioning and manufacturing system can perform many manufacturing operations on a single part without the need to adjust the part manually between operations. It also eliminates the need for separate precision positioning systems and grinding wheel dressing systems and tooling for multiple machines. Instead, it can use a single precision positioning system and a single grinding wheel dresser to carry out many different grinding operations. For instance, an inventive precision positioning and manufacturing system can perform three different grinding operations (e.g., grinding the ID, OD, and rib on of a tapered roller bearing) with three grinding wheels and just one precision positioning system, just one grinding wheel dressing systems, and just one set of tooling. This dramatically reduces cost of a capital equipment needed to produce the part. In addition to reducing capital costs, it also improves quality by performing all operations on the same tooling. And it reduces transport time and costs associated with making the part by eliminated the need to move the part among three different grinding machines.

A system for performing multiple manufacturing steps may include a workhead, a first tool, a second tool, and a positioning system supporting the workhead. In operation, the workhead hold a workpiece, the first tool performs a first machining operation on the workpiece, the second tool performs a second machining operation on the workpiece, and the positioning system moves the workhead and the workpiece linearly in a plane intersecting the first tool and the second tool. The positioning system also rotates the workhead and the workpiece about an axis perpendicular to the plane intersecting the first tool and the second tool.

The first and second tools can be first and second grinding wheels, respectively. The system may also include a grinding wheel dresser mounted on the positioning system. The positioning system moves the grinding wheel dresser within the plane intersecting the first grinding wheel and the second grinding wheel. And the grinding wheel dresser dresses the first grinding wheel and the second grinding wheel.

The positioning system can move the workpiece from the first tool to the second tool while the workpiece is on the workhead, which may rotate the workpiece about an axis of symmetry of the workpiece.

The axis perpendicular to the plane intersecting the first tool and the second tool may be a first axis. The positioning system may include first, second, and third rotary tables. In operation, the first rotary table rotates about the first axis. The second rotary table supports the first rotary table and rotates about a second axis parallel to the first axis and perpendicular to the plane intersecting the first tool and the second tool. And the third rotary table supports the second rotary table and rotates about a third axis parallel to the first axis and the second axis and perpendicular to the plane intersecting the first tool and the second tool.

Alternatively, the positioning system may include a rotary table, a first slide supporting the rotary table, and a second slide supporting the first slide. The rotary table rotates the workhead about the axis perpendicular to the plane intersecting the first tool and the second tool. The first slide moves the workhead and the rotary table in a first direction within the plane intersecting the first tool and the second tool. And the second slide moves the workhead, the rotary table, and the first slide in a second direction different than the first direction within the plane intersecting the first tool and the second tool.

The system may include a spindle, operably coupled to the first tool, to rotate the first tool with respect to the workpiece. It can also include a controller, operably coupled to the positioning system, to cause the positioning system to move the workpiece between the first tool and the second tool according to a motion plan. And it can include a slide, operably coupled to the first tool, to translate the first tool in the plane with respect to the workpiece.

A method for manufacturing a part from a workpiece includes securing the workpiece to a workhead. Once the workpiece has been secured, an eccentric positioning system moves the workpiece in the workhead to a first tool, which performs a first manufacturing operation on the workpiece while the workpiece is in the workhead. The eccentric positioning system moves the workpiece in the workhead from the first tool to a second tool (e.g., within under one minute), which performs a second manufacturing operation on the workpiece while the workpiece is in the workhead. For example, the first and second manufacturing operation may include grinding inner and outer diameters of a bearing or other part. After the second manufacturing operation has been completed, the workpiece can be removed from the workhead.

In some cases, a dresser (e.g., a rotary diamond dresser) mounted on the eccentric positioning system dresses the first tool. The eccentric positioning system moves the dresser from the first tool to the second tool, and the dresser dresses the second tool.

A multi-tool positioning and manufacturing system, which is not part of the present invention, may also include a top plate, workhead, first spindle, second spindle, third spindle, and eccentric positioning system. The workhead supports a workpiece in a plane parallel to the top plate. The first, second, and thirds spindles, which are supported by the top plate, spin first, second, and third grinding wheels, respectively, in the plane parallel to the top plate. And the eccentric positioning system, which supports the workhead and the grinding wheel dresser, moves the workhead and the workpiece in the plane parallel from the first grinding wheel to the second grinding wheel to the third grinding wheel.

The workhead can spin the workpiece about an axis of symmetry of the workpiece.

The eccentric positioning system can move the workhead laterally within the plane parallel to the top plate and to spin the workhead about an axis perpendicular to the plane parallel to the top plate.

Such as a multi-tool positioning and manufacturing system may also include first and second slides mounted to the top plate. The first slide supports the first and second spindles and translate them linearly in the plane parallel to the top plate. And the second slide supports the third spindle and moves it linearly in the plane parallel to the top plate.

The multi-tool positioning and manufacturing system can also include a grinding wheel dresser mounted on the eccentric positioning system. The eccentric positioning system moves the grinding wheel dresser within the plane parallel to the top plate. And the dresser dresses the first grinding wheel, the second grinding wheel, and the third grinding wheel.

The eccentric positioning system may include first, second, and third rotary tables. The first rotary table has a first axis of rotation. The second rotary table is mounted on the first rotary table and has a second axis of rotation parallel to the first axis of rotation. And the third rotary table is mounted on the second rotary table and has a third axis of rotation parallel to the first axis of rotation and the second axis of rotation.

In one embodiment, a system uses eccentric rotary motion to position an object with three degrees of freedom that provides linear motion in a plane and rotation of the item about an axis perpendicular to that plane. In this embodiment all tools are in fixed positions.

In another embodiment, a system uses eccentric rotary motion to position an object with three degrees of freedom that provides linear motion in a plane and rotation of the item about an axis perpendicular to that plane. In this embodiment one or more tools can be moved along one or more linear axes of motion in the direction(s) of interest.

In yet another embodiment, a system uses two linear position systems that are located at right angles to each other and a rotary table to position an object with <NUM> degrees of freedom that provides linear motion in a plane and rotation of the item about an axis perpendicular to that plane. In this embodiment all tools are in fixed positions.

In still another embodiment, a system uses two linear position systems that are located at right angles to each other and a rotary table to position an object with <NUM> degrees of freedom that provides linear motion in a plane and rotation of the object about an axis perpendicular to that plane. In this embodiment one or more tools can be moved along one or more linear axes of motion in the direction(s) of interest.

Other objects, features, and advantages will occur to those skilled in the art from the following description of the preferred embodiments of the invention and the accompanying drawings, in which:.

A multi-tool precision positioning and manufacturing system can do multiple manufacturing operations on a single part. For example, it can grind the inner and outer diameters of a ball bearing's inner and outer rings; the inner diameter, outer diameter, and rib of a tapered roller bearing inner ring; or the three grinding operations for making a fuel injector. Moreover, it can perform sequential operations without any need to manually align or position the part between operations. Its precision positioning system moves the part from tool to tool with a precision of <NUM> microns in less than <NUM> seconds (e.g., less <NUM> seconds, less than <NUM> seconds, less than <NUM> seconds, less than <NUM> seconds, less than <NUM> second, or even less than <NUM> seconds). If each manufacturing operation takes about <NUM> seconds, then the total time to perform three operations is less than <NUM> seconds. In contrast, it can take several minutes just to transfer a workpiece from one grinding machine to another grinding machine, which is longer than it would take to perform all of the grinding operations with a multi-tool precision positioning and manufacturing system.

Replacing many tools with a single multi-tool precision positioning and manufacturing system offers other advantages as well. To start, a single multi-tool precision positioning and manufacturing system has a higher yield than two or more separate tools because the part isn't moved from tooling to tooling or machine to machine, reducing the opportunities for misalignment. For example, when using a multi-tool precision positioning and manufacturing system to perform three grinding operations, a machinist places the part in a shoe just once, giving only one chance for misalignment of the part with respect to the shoe. When performing three grinding operations with three separate grinding machines, the machinist must put the part in three separate shoes, there are three chances to misalign the part with respect to a shoe. If misalignment occurs during any one of these chances, the part could be ruined.

Using a single multi-tool precision positioning and manufacturing system instead of multiple tools also reduces energy consumption. The system and tools each consume about the same amount of baseline idle current, so replacing conventional tools with a smaller number of multi-tool precision positioning and manufacturing systems reduces total baseline current consumption. In addition, a single multi-tool precision positioning and manufacturing system consumes less electrical power in moving and positioning a workpiece than the total electrical power consumed by separate machines for moving and positioning a workpiece.

In addition, a single multi-tool precision positioning and manufacturing system is more compact than the tools that it replaces. As a result, it can be used in a smaller machine shop or the machine shop can be made smaller. This translates to lower construction costs, lower rent, lower heating and cooling costs, etc., for the manufacturing facility. And it uses fewer components-e.g., a single controller versus one controller per tool, a single dressing system versus one dressing system per tool, and so on-so it can be less expensive that the tools that it replaces. All of this means that a multi-tool precision positioning and manufacturing system can be less expensive to buy and operate than the tools that it replaces.

<FIG> shows a multi-tool positioning and manufacturing system <NUM> with an eccentric positioning system <NUM>. The system <NUM> includes a base <NUM> that contains and protects the eccentric positioning system <NUM>. The base <NUM> also supports a top plate <NUM>, which in turn supports two or more tools. In this example, the top plate <NUM> supports a first tool <NUM> mounted on a first motorized grinding spindle <NUM>, a second tool <NUM> mounted on a second motorized grinding spindle <NUM>, a third tool <NUM> mounted on a third motorized grinding spindle <NUM>, and a non-rotating turning tool <NUM>. The first tool <NUM>, second tool <NUM>, third tool <NUM>, and non-rotating turning tool <NUM> all intersect a plane parallel to the top plate <NUM>.

The top plate <NUM> also defines a hole or aperture for access to the eccentric positioning system <NUM>. A workhead <NUM> mounted to the eccentric positioning system <NUM> or the top of the eccentric positioning system <NUM> protrudes through this hole, allowing the eccentric positioning system <NUM> to move the workhead <NUM> with respect to the components mounted to the top plate <NUM>. The workhead <NUM> locates, supports, and rotates a workpiece <NUM>, such as the inner race of a tapered roller bearing made of hardened steel, about its axis of symmetry in the same plane that intersects first tool <NUM>, second tool <NUM>, third tool <NUM>, and non-rotating turning tool <NUM> and is parallel to the top plate <NUM>. The eccentric positioning system <NUM> also supports and moves a rotary diamond dresser <NUM> in this plane for dressing and/or shaping the grinding wheels <NUM>, <NUM>, and <NUM> shown in <FIG> as explained below.

The workpiece <NUM> may be secured to the workhead <NUM> with tooling, such as shoes or a chuck. In operation, the workhead <NUM> can rotate the chuck or a (magnetic) backing plate, which in turn rotates the workpiece <NUM>. It typically takes <NUM>-<NUM> minutes to install the tooling (e.g., the shoes and backing plate) on the workhead <NUM>. Once the tooling has been installed properly, the workpiece <NUM> (e.g., a part to be ground) can be secured to the tooling by the machine operator, robot, or dedicated workpiece loading and unloading mechanism. The machine operator, robot, or dedicated workpiece loading and unloading mechanism can also remove any part that has just been ground. The length of time it takes to replace a ground part with an unground ("black") part depends on the size of the part, tooling type (e.g., three-jaw chuck, magnetic chuck, or shoe tooling), and loading system (e.g., manual, dedicated electro-mechanical system, or general-purpose robot) and take from <NUM> second to <NUM> minutes.

In operation, the eccentric positioning system <NUM> positions the workpiece <NUM> and the workhead <NUM> with three degrees of freedom in a plane parallel to the base <NUM>. That is, the eccentric positioning system <NUM> can move the workpiece <NUM> linearly within that plane (two-dimensional translational motion) and rotate the workpiece <NUM> about an axis perpendicular to that plane (one-dimensional rotational motion). The eccentric positioning system <NUM> moves the workpiece <NUM> (and the workhead <NUM>) to a particular tool, holds the workpiece <NUM> in place as the tool removes material from the workpiece <NUM>, then moves the workpiece to the next tool automatically. The workpiece <NUM> remains on the workhead <NUM> during all of the operations performed by the tools. , eliminating any need for manual repositioning between operations by different tools.

Consider, for example, making a tapered roller bearing cone with the multi-tool positioning and manufacturing system <NUM> in <FIG>. First, a machinist secures the workpiece <NUM> to the workhead <NUM>. Then the eccentric positioning system <NUM> moves the workpiece <NUM> to the first grinding wheel <NUM>. The first motorized grinding spindle <NUM> rotates the first grinding wheel <NUM> to create the rib surface of tapered roller bearing cone. Once the first grinding wheel <NUM> has finished grinding the rib surface, the first motorized grinding spindle <NUM> stops rotating, and the eccentric positioning system <NUM> moves the workpiece <NUM> to the second grinding wheel <NUM>, which is spun by the second motorized grinding spindle <NUM> to grind the outer race of tapered roller bearing cone. And once the second grinding wheel <NUM> has finished grinding the outer race surface, the second motorized grinding spindle <NUM> stops rotating, and the eccentric positioning system <NUM> moves the workpiece <NUM> to the third grinding wheel <NUM>, which is spun by the third motorized grinding spindle <NUM> to grind the inside diameter of the tapered roller bearing cone. The third motorized grinding spindle <NUM> stops rotating once the inside diameter has been ground. Then the eccentric positioning system <NUM> moves the workpiece <NUM> to the non-rotating turning tool <NUM>, which removes material from both the inside diameter and outside diameter raceway of the workpiece <NUM>. (The operation performed by the non-rotating turning tool <NUM> could be considered a super finishing or honing operation. ) Finally, the machinist removes the workpiece <NUM> from the workhead <NUM>.

A multi-tool positioning and manufacturing system can have other tools and perform other operations as well. For example, the tools may not rotate or spin, nor do they have to be mounted on motorized grinding spindles. For example, many operations performed by a lathe, e.g., drilling, countersinking, counterboring, or chamfering, could be performed by mounting the tool in a stationary chuck. The workpiece can be rotated with respect to the tool or the tool and chuck can be mounted on the top plate as mentioned below. One or more of these lathe operations can be carried out on a complex part before or after one or more grinding steps. Other suitable tools include lasers for hole drilling, milling cutters, and single- and multi-point turning (lathe) tools. At one extreme, a multi-tool positioning and manufacturing system duplicates the functions of a three-axis horizontal computer numerical control (CNC) milling machine combined with a grinding system.

The eccentric positioning system <NUM> also positions the rotary diamond dresser <NUM> to dress or shape the grinding wheels <NUM>,<NUM> and <NUM> shown in <FIG>. The rotary diamond dresser <NUM> removes metal, dull and misshapen grains, and bonding material from the grinding material on the grinding surfaces of the grinding wheels <NUM>,<NUM> and <NUM>. This sharpens the grinding wheel. The rotary diamond dresser <NUM> may also return the grinding surfaces to their original shapes. And it can remove material from a grinding surface so that the resultant grinding surface runs true to some other surface.

Because the rotary diamond dresser <NUM> is mounted on the eccentric positioning system <NUM>, it can dress all three grinding wheels <NUM>,<NUM> and <NUM>, eliminating the need for a separate dresser for each wheel. Thus, the multi-tool positioning and manufacturing system <NUM> can carry out four machining operations and three dressing operations to be accomplished with one eccentric positioning system, reducing cost and increasing productivity and improving manufacturing accuracy.

<FIG> is a cutaway view of the multi-tool positioning and manufacturing system <NUM> with components <NUM> through <NUM> and <NUM> omitted to show the eccentric positioning system <NUM> in greater detail. The eccentric positioning system <NUM> is comprised of three circular eccentric rotary tables <NUM>, <NUM>, and <NUM>. The workhead <NUM> and the rotary diamond dresser <NUM> are mounted on the top eccentric rotary table <NUM>, which is mounted on the middle eccentric rotary table <NUM>, which in turn is mounted on the bottom eccentric rotary table <NUM>. The eccentric rotary tables <NUM>-<NUM> are not concentric when viewed from above or below. Instead, the eccentric rotary tables <NUM>-<NUM> rotate about different, parallel axes. This enables the eccentric positioning system <NUM> to translate the workhead <NUM>, workpiece <NUM>, and rotary diamond dresser <NUM> in any direction in the plane perpendicular to these rotational axes. The eccentric positioning system <NUM> can also rotate the workhead <NUM>, workpiece <NUM>, and rotary diamond dresser <NUM> about an axis parallel to or coincident with any one of the rotational axes of the eccentric rotary tables <NUM>-<NUM>.

The eccentric positioning system <NUM> can be controlled by a computerized control system (not shown). This control system is used to control the position, angle of rotation, and linear and rotary velocities and accelerations of the top eccentric rotary table <NUM>. It may be programmed with a motion plan that sets the trajectory of the workpiece <NUM> as described in greater detail below.

<FIG> is a simplified top view of three nested bearings of the eccentric positioning system <NUM>. A largest, outer bearing <NUM> encompasses a mid-size bearing <NUM> and a smallest, inner bearing <NUM>. The bearings are eccentrically mounted such that they each can rotate about a different but parallel axis as described above; as the rotations take place, these axes may become temporarily coincidental. The bearings are supported such that when the inner race of the outer bearing <NUM> is rotated, the other bearings <NUM> and <NUM> (and any structures or objects supported by such bearings) also move about the axis of rotation of the outer bearing <NUM>. Similarly, when the inner race of the middle bearing <NUM> is rotated, the inner bearing <NUM> (and any structures or objects supported by the inner bearing <NUM>) move as well. The workpiece <NUM> is directly or indirectly coupled to the inner race of the inner bearing <NUM> via the workhead <NUM> and moves with the inner race of the inner bearing <NUM>.

A solid circle <NUM> shows the path of the center of the mid-sized bearing <NUM> when the outer bearing <NUM> rotates. A dashed circle <NUM> shows the path of the center of the inner bearing <NUM> when the mid-sized bearing <NUM> rotates. The outer bearing <NUM> and/or mid-sized bearing <NUM> control the motion of the workpiece <NUM> in the X-Z plane, which is parallel to the drawing page. The workpiece <NUM> is coupled to the inner bearing <NUM> such that the workpiece <NUM> is rotated about the axis of rotation of the inner bearing <NUM>. The inner bearing <NUM> thus controls the angular orientation (theta) of the workpiece <NUM> in the XZ plane. As is evident from this drawing, the inner bearing <NUM> has an effect on the X and Z position as well as the angular orientation.

<FIG> illustrate one example of the direction and extent in degrees of rotary motion of the bearings <NUM>, <NUM>, and <NUM> that move the workpiece <NUM> in a generally straight line along the "Z" axis, from the start position shown in <FIG> to the end position shown in <FIG>. The workpiece <NUM> has the same angular orientation at the start and end of this motion, as shown in <FIG>. The motions can take place simultaneously or sequentially and are controlled appropriately by the system controller. In situations in which the path of motion is important, e.g., to avoid hitting another object with the workpiece <NUM>, straight-line or other purposeful, directed object motion can be accomplished.

In this example, the outer bearing <NUM> has an OD of <NUM> centimeters (<NUM> inches) and an ID of <NUM> centimeters (<NUM> inches). The mid-sized bearing <NUM> has an OD of <NUM> centimeters (<NUM> inches) and an ID of <NUM> centimeters (<NUM> inches). And the inner bearing <NUM> has an OD of <NUM> centimeters (<NUM> inches) and an ID of <NUM> centimeters (<NUM> inches). The motions include clockwise motion of large bearing <NUM> amounting to <NUM> degrees, counterclockwise motion of mid-size bearing <NUM> of <NUM> degrees, and clockwise motion of smallest bearing <NUM> of <NUM> degrees. With these dimensions and rotations, the workpiece moves about <NUM> centimeters (<NUM> inches) in the Z dimension.

<FIG> illustrate motions that move the workpiece <NUM> in the X direction. In this case, the workpiece <NUM> translates from the starting position shown in <FIG>, which is the same as that shown in <FIG>, to the position shown in <FIG>. The total (absolute) rotational motion of the inner races of bearings <NUM>, <NUM> and <NUM>, respectively, are: clockwise <NUM> degrees, counterclockwise <NUM> degrees, and clockwise <NUM> degrees. For the bearing dimensions given above, this equates to line motion of <NUM> centimeters (<NUM> inches) in the "X" direction.

To maintain single-axis linear motion, the overall positioning can take place in two steps: e.g., the Z axis motion shown in <FIG>, and then the X axis motion shown in <FIG>, in either order. The eccentric positioning system <NUM> is not constrained to moving the workpiece <NUM> along a single axis or even in a straight line; it can move the workpiece along curved or bent paths with the plane as well.

For more information on the eccentric positioning system <NUM>, see <CIT>.

<FIG> illustrates a control system <NUM> for the eccentric positioning system <NUM>. The control system <NUM> includes a controller <NUM>, such as a Rockwell, ACS, Siemens or FANUC controller that executes appropriate motion control software. The controller <NUM> is coupled to servo motors <NUM> in the eccentric positioning system <NUM>. These servo motors <NUM> are in turned coupled to the eccentric positioning system's mechanical system <NUM>.

The control system <NUM> can be used to control motion of the workpiece <NUM> or the grinding wheel dresser <NUM> depending on whether the current operation is modifying the workpiece <NUM> or shaping the grinding wheels <NUM>, <NUM> and <NUM>. The controller <NUM> moves the workpiece <NUM> or grinding wheel dresser <NUM> according to a motion plan <NUM>, which comprises motion control parameters input by the operator specific to the workpiece <NUM>. The motion control parameters in the motion plan <NUM> are selected so that the positioning system <NUM> moves the workpiece <NUM> from tool to tool and keeps the workpiece <NUM> in place for each machining operation. The controller <NUM> uses these motion control parameters to generate and send appropriate control signals to the servo motors <NUM>, which interact with the mechanical system <NUM> to cause object motion <NUM>.

<FIG> shows a multi-tool positioning and manufacturing system <NUM> with moving slides for the tools. Again, the eccentric positioning system <NUM> positions the workpiece <NUM> with three degrees of freedom (two linear degrees of freedom and one rotational degree of freedom) in a plane parallel to the top plate <NUM>. The first motorized grinding spindle <NUM> and second motorized grinding spindle <NUM> are mounted on a first sliding table <NUM>, which is on a first base <NUM> mounted to the top plate <NUM>. And the third motorized grinding spindle <NUM> and non-rotating turning tool <NUM> are mounted a second sliding table <NUM>, which is on a second base <NUM> mounted to the top plate <NUM>.

The slides <NUM> and <NUM> can move the spindles in the X direction independent of the workpiece <NUM> and rotary diamond dresser <NUM> and can be controlled by the same controller (e.g., controller <NUM> in <FIG>) that controls the eccentric positioning system <NUM>. (In this example, the first slide <NUM> moves the first motorized grinding spindle <NUM> and second motorized grinding spindle <NUM> together, i.e., as a single unit. ) The slides <NUM> and <NUM> can be used to position tools that are beyond the range of the eccentric positioning system, such as a bearing for a gas turbine engine which might be several meters (several feet) in diameter. There is no practical limit to the length of the slide, so a single long slide could support several spindles. The slide could move these spindles back and forth to roughly align the workpiece with the workhead before the positioning system performs the fine positioning for grinding.

The slides <NUM> and <NUM> can also be mounted differently to move in different directions and/or modified to move in additional directions. For example, either slide could be rotated by <NUM>° to move the corresponding tool in the Z direction. This is just an example; other slide orientations (e.g., <NUM>°, <NUM>°, <NUM>°, and so on) are also possible. Similarly, either slide may move the corresponding tool(s) in the Y direction, toward or away from the top plate <NUM>. A slide made also move laterally in two dimensions (e.g., the X and Z directions). Y motion is particular useful in applications where the workpiece <NUM> did not have an axis of symmetry, flat surface grinding, and gear tooth grinding to accommodate different diameter gears.

<FIG> and <FIG> show a multi-tool positioning and manufacturing system <NUM> with a rotary and linear positioning system <NUM> instead of an eccentric positioning system. The rotary and linear positioning system <NUM> includes a rotary table <NUM>, Z linear slide <NUM>, and X linear slide <NUM> that sit inside the base <NUM> and are covered by the top plate <NUM>. The top plate <NUM> supports the spindles <NUM>, <NUM>, and <NUM> and turning tool <NUM>. The workhead <NUM> and rotary diamond dresser <NUM> are mounted on the rotary table <NUM> and protrude through a hole in the top plate <NUM> (or at least a portion of the rotary table <NUM> protrudes through the hole in the top plate <NUM>).

Together, the rotary table <NUM>, Z linear slide <NUM>, and X linear slide <NUM> move the workhead <NUM> (and the workpiece <NUM>, which is on the workhead <NUM>) and the rotary diamond dresser <NUM> within a plane parallel to the top of the top plate <NUM>. The X linear slide <NUM> and Z linear slide <NUM> move the workhead <NUM>, workpiece <NUM>, and rotary diamond dresser <NUM> in the X and Z directions, respectively. The rotary table <NUM> rotates the workhead <NUM>, workpiece <NUM>, and rotary diamond dresser <NUM> about an axis that extends in the Y direction. This rotational axis can be repositioned by moving the rotary table <NUM> using the X linear slide <NUM> and Z linear slide <NUM>.

The X linear slide <NUM>, Z linear slide <NUM>, and rotary table <NUM> can move simultaneously, sequentially, and independently according to a motion plan executed by a suitably programmed control system (e.g., control system <NUM> in <FIG>). This control system is used to control the position, angle of rotation and linear and rotary velocity and acceleration of the rotary table <NUM> to which the workhead <NUM> and the rotary diamond dresser <NUM> are mounted. As explained above, the rotary diamond dresser <NUM> is used to dress or shape the grinding wheels <NUM>,<NUM> and <NUM>. And the workhead <NUM> locates, supports, and rotates the workpiece <NUM> about its axis of symmetry.

For example, consider the workpiece <NUM> may be the inner race of a tapered roller bearing made of hardened steel. The workhead <NUM> is used to locate, support, and rotate the inner race about its axis of symmetry. The rotary and linear positioning system <NUM> moves the inner race to the first motorized grinding spindle <NUM>, which rotates the first grinding wheel <NUM> to grind the rib surface of the inner race. Then the rotary and linear positioning system <NUM> moves the inner race to the second motorized grinding spindle <NUM>, which rotates the second grinding wheel <NUM> to grind the outer diameter of the inner race. The rotary and linear positioning system <NUM> then moves the inner race to the third motorized grinding spindle <NUM>, which rotates the third grinding wheel <NUM> to grind the inside diameter of the inner race. Finally, the rotary and linear positioning system <NUM> moves the inner race to the non-rotating turning tool <NUM>, which removes material from both the inside diameter and outside diameter of the inner race.

<FIG> shows a multi-tool positioning and manufacturing system <NUM> with a rotary and linear positioning system <NUM> with slides for the tools. It is like the embodiment shown in <FIG>, but the tools are mounted to two slides that supply independent motion of the tools in the X direction. <FIG> shows two X direction slides-sliding tables <NUM> and <NUM>-which are mounted to bases <NUM> and <NUM>, respectively, as in <FIG> and provide the same degrees of freedom as described above with respect to <FIG>.

Claim 1:
A system (<NUM>, <NUM>, <NUM>, <NUM>) for performing multiple manufacturing steps, the system comprising:
A workhead (<NUM>) to hold a workpiece (<NUM>);
a first tool (<NUM>) to perform a first machining operation on the workpiece;
a second tool (<NUM>) to perform a second machining operation on the workpiece; characterized by an eccentric positioning system (<NUM>, <NUM>), supporting the workhead, to position the workhead and the workpiece with three degrees of freedom in a plane intersecting the first tool and the second tool, the three degrees of freedom providing (i) two linear degrees of freedom in the plane intersecting the first tool and the second tool, and (ii) one rotational degree of freedom about an axis perpendicular to the plane intersecting the first tool and the second tool.