WO1998033622A1

WO1998033622A1 - Method and apparatus for cutting windows in a constant-velocity joint cage

Info

Publication number: WO1998033622A1
Application number: PCT/US1997/001309
Authority: WO
Inventors: Graham Le Grove; David G. Suttie
Original assignee: Raycon Corporation
Priority date: 1997-01-30
Filing date: 1997-01-30
Publication date: 1998-08-06
Also published as: AU1756497A

Abstract

Under the direction of a computer numerical control, a multi-axis manipulator (66) moves the collet and an attached cage supported by a cage holder (54) along an interpolated motion control path to cause a stationary laser beam from a laser generator to cut windows in the cage. The manipulator (66) includes multi-axis translators and rotators that allow formerly impractical window geometries to be produced. A beam exit casing includes a lens that converges the laser beam and a mirror that bends the beam to a ninety-degree cutting angle. The beam-bending mirror is disposed between the lens and a reflected image-side focal point of the lens. The resulting proximity of the mirror to the focal point allows the beam bender nose to fit into and cut from within a confined space such as a CV joint cage interior.

Description

METHOD AND APPARATUS FOR CUTTING WINDOWS IN A CONSTANT-VELOCITY JOINT CAGE

TECHNICAL FIELD

This invention relates generally to an apparatus and method for cutting windows from constant velocity universal (CV) joint cages and, more particularly, to an apparatus and method for cutting such windows using a laser.

BACKGROUND OF THE INVENTION

Constant velocity universal joint cages are used to guide torque-transmitting ball bearings in universal joints. Such cages typically have annular semi-spherical shapes designed to nest between convex and concave spherical surfaces of articulating CV joint members. A plurality of windows (usually 6 and sometimes 8) are evenly spaced around each cage circumference. Each window guides a single torque- transmitting ball bearing along grooves formed in the respective convex and concave spherical surfaces of the articulating CV joint members. Wall surfaces defining each window must be formed to close tolerances to insure that the windows will successfully guide their respective ball bearings in the true median plane of the joint, regardless of how the joint may articulate.

A conventional method of forming windows in metal cages for guiding roller elements is by punching the windows out of metal cage blanks. However, punching operations of this type typically result in poor edge quality. Therefore, additional steps are necessary to achieve the necessary tolerances. These additional steps conventionally include the use of a "broach" cutting tool which simultaneously machines the side and end walls of two diametrically-opposed cage windows. This is accomplished by passing the cutting tool completely through the cage via the two opposed windows. In most circumstances it is then necessary to grind the inside of each window to achieve the required precision for the cage.

The simultaneous broaching of two diametrically opposed windows obviously requires a CV joint cage to have windows disposed in diametrically- opposed pairs with window side and end walls that are parallel to each other. As shown in Fig. 1, parallel side walls 284' result in ribs 286' with trapezoidical window rib profiles. These are not necessarily optimum geometrical attributes for a CV joint cage. However, more optimum geometries can be difficult and uneconomical to manufacture.

An example of a window-punching operation is disclosed in United States Patent Numbers 4,689,982 and 5,410,902. Following window punching, these patents disclose the additional time-consuming steps of heat treating and finish grinding to form the windows to required tolerances.

It has been proposed to use a laser beam to cut portions of a CV joint cage. United States Patent Number 4,942,652 to Hazebroo et al . (the Hazebrook patent) makes general reference to the possibility of using a laser to cut an annular semi-spherical CV joint cage. However, rather than cutting windows into a "complete" CV joint cage blank, the Hazebrook method contemplates fabricating the cage in two "circularly shaped multi-limbed starfish" - shaped halves that are later joined together to form a complete annular semi- spherical cage. The Hazebrook patent does not disclose a method for cutting windows from a complete CV joint cage blank.

There are laser delivery systems currently available with laser generators that produce laser beams strong enough to cut metal the thickness of a CV joint cage wall. Some of these systems include convergent lenses that focus laser beams to a small focal width for cutting. Some of these systems also include beam bending mirrors that re-direct laser beams to aim at surfaces that might otherwise be difficult to reach. For example, United States Patent Number 4,760,583, issued to Coherent, Inc. (the Coherent patent) , discloses such a system. As shown in Fig. 11 of the patent, the system includes a beam bender assembly with a final beam-bending mirror 156 and a focusing lens 158. However, the beam bender assembly disclosed in the

Coherent patent does not pass the beam through the focusing lens 158 until after beam bending is complete. This requires the mirror 156, the lens 158 and the full focal length (typically five inches) of the focusing lens 158 to all be aligned in the direction of the exiting laser beam. Consequently, the distance measured along a ray extending from an image-side focal point of the focusing lens 158, upstream along the beam path and through the final beam-bending mirror 156 to the furthest extremity of the beam-bender assembly, i.e., the "insertion width," may be well in excess of 5 inches.

It is difficult if not impossible to accommodate insertion widths in excess of 5 inches in the interior of a CV joint cage that has an inside diameter of less than 5 inches. Therefore, CV joint cage windows must be cut from the outside-in when using a laser delivery system with insertion widths greater than the inside diameter of the CV joint cage to be cut.

When high-energy lasers are used to cut a complete CV joint cage from the outside-in, hot byproducts of the laser cutting operation, such as offal, dross, window slugs and metal combustion byproducts are allowed to contact, coat and/or fuse themselves to the CV joint cage interior. In addition, once the laser beam has penetrated a target wall of a CV joint cage from the outside-in, undesirable secondary laser cutting can occur on a portion of the interior surface of a CV joint cage diametrically opposite the target wall. Still further, a focused, radially- inwardly directed high-energy laser beam will cause a rapid heat build-up within the target CV joint cage and its vicinity - a build-up that would be extremely difficult to dissipate.

What is needed is a method and apparatus for cutting conventional and/or alternative window geometries from a complete CV joint cage blank while producing a minimum of offal and dross. What is also needed is an apparatus for cutting such windows that includes a beam bender assembly with an insertion width smaller than the interior diameters of most or all CV joint cages thereby allowing laser cutting to be accomplished from the inside-out. SUMMARY OF THE INVENTION

In accordance with this invention a method is provided for making inside-out angled laser cuts from within a confined space such as the interior of a CV joint cage blank. The method employs an apparatus that comprises a laser beam-bender assembly including a final beam-bending mirror disposed between a beam-converging lens and the reflected image-side focal point of the lens. By positioning the final beam-bending mirror close to the focal point, a nose portion of the beam bender assembly can be made small enough to fit within a confined space and to make angled laser cuts from within that confined space.

The apparatus additionally comprises a laser generator that emits a laser beam along a laser beam path when energized. A cage holder is disposed adjacent the beam path to releasably hold a CV joint cage for laser cutting. A manipulator is operatively connected to at least one of the laser generator and the cage holder to direct a laser beam from the laser generator at a wall of the cage. The manipulator manipulates at least one of the laser beam and the cage holder to cause the laser beam to cut a window-shaped slug from the cage wall.

The beam-bender assembly is optically coupled to the laser generator. To support the final beam bending mirror and the beam-converging lens, the beam- bender assembly includes a casing. The beam-bender assembly has an insertion width measured along a ray extending from the image-side focal point of the beam- converging lens along the beam path and through the final beam-bending mirror to the furthest extremity of the beam-bender assembly along that ray. According to another aspect of the present invention, the beam-bender assembly includes a cooling system in the form of a water jacket disposed adjacent the final beam-bending mirror. The water jacket extracts heat energy built-up in the final bending mirror by the converging laser beam.

According to another aspect of the present invention, the beam-bender assembly includes a beam exit nozzle supported adjacent the final beam-bending mirror in a nose portion of the casing. The beam exit nozzle provides an aperture for the converging laser beam to exit through.

According to another aspect of the present invention, the manipulator includes a B-axis rotator for rotating the cage holder about a central rotational "B" axis and an A-axis tilt mechanism for tilting the cage holder. The A axis is disposed perpendicular to and intersects the B axis.

According to another aspect of the present invention, the manipulator includes an X-axis translator for moving the cage holder laterally along a horizontal translational X axis that is disposed perpendicular to the B axis. A Y-axis translator moves the cage holder laterally along a horizontal translational Y axis that is disposed perpendicular to the X axis. A Z-axis translator moves the beam-bender assembly vertically along a vertical translational Z axis that is disposed perpendicular to the X and Y axes.

According to another aspect of the present invention, the beam-bender assembly is physically supported on and fixed in relation to the laser generator .

According to another aspect of the present invention, the laser generator comprises a C0₂ laser.

According to another aspect of the present invention, a cage loader assembly is disposed adjacent the cage holder to supply blank CV joint cages to the cage holder. The cage loader assembly comprises a load track and a loader-gripper-slide disposed adjacent an exit end of the load track. The loader-gripper-slide includes a load gripper that moves between a loader pick-up position adjacent the load track exit end and the cage holder. The loader-gripper-slide also includes radially-extendable keeper fingers mounted on the load gripper. The fingers are pneumatically driven in a radially outward direction to engage CV joint cage blanks from within.

According to another aspect of the present invention, the cage holder comprises a radially- segmented spindle. Each the spindle segment is movable between a radially outward cage-engagement position and a radially inward cage-release position. The spindle includes a central spindle aperture for receiving a tapered rod. Reciprocal coaxial movement of the rod within the aperture drives the spindle segments between their engaged and disengaged positions. The spindle also includes a sliding cover that protects radially- extending gaps between the spindle segments from offal , dross and other contaminants.

According to another aspect of the present invention, a slug conveyor belt is disposed below the cage holder to catch and remove hot slugs. The slug conveyor belt is made of Kevlar®.

According to another aspect of the present invention, a cage unloader assembly is disposed adjacent the cage holder for removing CV joint cages from the cage holder after laser cutting. The cage unloader assembly includes an unload track and an unloader- gripper-slide. The unloader-gripper-slide includes an unload gripper mounted for reciprocal translational movement between the cage holder and an input end of the unload track. Radially-extendable keeper fingers are supported on the unload gripper for reciprocal radial movement.

According to still another aspect of the present invention, an electronic controller connected to the manipulator to controlling the speed and position of all linear and conventional motors.

According to another aspect of the present invention, a method is provided for cutting a window in a CV joint cage using the claimed apparatus. The method includes moving a cage to a position adjacent the cage holder, causing the cage holder to engage the cage then moving either the cage, the beam-bender assembly, or both to place the nose portion of the beam-bender assembly inside the cage in a position where the nozzle is aiming at the point on the inner cage wall where a cage window is to be cut. The laser is then energized to burn a hole through the cage wall. Either the laser, the cage, or both, are then manipulated to cause the laser beam to cut a window-shaped slug from the cage wall. The cage is then rotated around the B axis and the cutting process is repeated until a desired number of window-shaped slugs have been cut from around the cage wall. The laser is then shut off and either the cage, the laser beam-bender, or both are moved to position the beam-bender nose outside the cage.

According to another aspect of the present invention, the manipulating step includes the step of aiming the laser beam downward toward a portion of the cage disposed below the beam-bender nozzle. This allows the slugs to drop free to the slug conveyor belt instead of dropping inside the cage.

The manipulating step may also include the steps of rotating the cage around the cage central rotational B axis to make circumferential cuts in the cage wall, moving the cage in a direction parallel to the B axis to make cuts in the cage wall that are perpendicular to the circumferential cuts, and tipping the cage about an A axis, perpendicular to the B axis to control the beam cutting angle relative to the cage wall inner surface and to compensate for a hole tapering phenomenon inherent in the laser cutting process.

The step of forming a window side wall may include the step of adjusting the pitch of the side wall by rotating a cage holder collet of the cage holder around the B axis. The side wall pitch may be adjusted to compensate for inherent hole taper and/or to vary rib profiles .

The manipulating step may also include the step of moving at least one of the cage holder and the beam-bender assembly along a computer numerically controlled multi-axis interpolated motion control path. According to another aspect of the present invention, the method may include initially positioning the beam-bender nozzle to aim at a portion of the inner circumferential surface of the cage wall interior to where the cage window perimeter walls are to be cut. This keeps the area of extra burn, i.e., the initial "burn-through" area, away from where the window perimeter walls will be.

According to another aspect of the present invention, the method includes the additional step of injecting a coaxial assist gas into the casing thereby forcing the gas to exit the casing through the nozzle during lasing. This assists with the cutting process by helping to vaporize and burn-away the metal.

According to another aspect of the present invention, the method includes moving the cage holder to an unload position after cutting is complete, then engaging the cage with the unloader-gripper-slide and removing the cage from the cage holder. The unloader- gripper-slide then transports the cage to an unload track and releases the cage to roll down the unload track .

BRIEF DESCRIPTION OF THE DRAWINGS

To better understand and appreciate the invention, refer to the following detailed description in connection with the accompanying drawings:

Figure 1 is a cross-sectional side view of a prior art constant velocity joint cage; Figure 2 is a perspective view of a constant velocity joint cage manufactured by the method and apparatus claimed in the present invention;

Figure 3 is a cross-sectional side view of the constant velocity joint cage of Fig. 2;

Figure 4 is a plan view of a laser cutting apparatus constructed according to the present invention;

Figure 5 is a front view of the laser cutting apparatus of Fig. 4;

Figure 6 is a front view of a beam-bender assembly lower end constructed according to the present invention;

Figure 7 is a partial cross-sectional side view of the beam-bender assembly lower end of Fig. 6;

Figure 8 is a perspective view of a water jacket of the beam-bender assembly lower end of Fig. 6;

Figure 9 is a partial cross-sectional top view of a cage holder, a B axis rotator, and an A axis tilt mechanism constructed according to the present invention;

Figure 10 is a partial cross-sectional side view of the cage holder and B axis rotator taken along line 10-10 of Fig. 9 ;

Figure 11 is a back view of the B axis rotator and A axis tilt mechanism of Fig. 9; Figure 12 is a fragmentary partial side view of the B axis rotator and A axis tilt mechanism of Fig. 9;

Figure 13 is a partially cut-away cross- sectional view of the A axis tilt mechanism taken along line 13-13 of Fig. 9;

Figure 14 is a fragmentary partial cross- sectional side view of the cage holder, B axis rotator, and A axis tilt mechanism of Fig. 9;

Figure 15 is a fragmentary front view of a cage loader assembly and a cage unloader assembly constructed according to the present invention;

Figure 16 is a partially cut-away partial side view of a first cutting station of the laser cutting apparatus of Fig. 4;

Figure 17 is a front view of a laser column support tower of the first cutting station of Fig. 16;

Figure 18 is a top view of a cage loader assembly and a cage unloader assembly of the first cutting station of Fig. 16 and a fragmentary diagrammatic view of the cage holder, B axis rotator, and A axis tilt mechanism of Fig. 9;

Figure 19 is a perspective view of a cage- holder collet of the cage holder of Fig. 9;

Figure 20 is a partially cut-away cross sectional side view of an unloader cage gripper of the cage unloader assembly of Fig. 18; Figure 21 is a cross sectional end view of the unloader cage gripper of Fig. 20 taken along line 21-21 of Fig. 20; and

Figure 22 is an end view of a modified SMC gripper of the unloader cage gripper of Fig. 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An apparatus for cutting windows in constant- velocity joint cages and the like is generally shown at 20 in Figs. 4, 5 and 16. The apparatus 20 includes a single laser system, generally indicated at 22 in Figs.

4, 5 and 16. The laser system 22 includes a laser generator, shown at 24 in Fig. 4, and a laser beam- bender assembly, generally indicated at 26 in Figs. 4,

5, 6, 7 and 16. The laser generator 24 comprises an Arrow Ultimate 10 watt convergent energy C0₂ laser.

The apparatus 20 also includes first and second cutting stations, generally indicated at 28 and 30, respectively, in Figs. 4 and 5. Both cutting stations 28, 30 are enclosed in a single class-I laser enclosure, shown at 32 in Figs. 4 and 5.

The laser generator 24 emits a laser beam along a laser beam path, shown at 25 in Figs. 4-7 and 16, when energized. The beam-bender assembly 26 defines the laser beam path 25 and includes a series of conduits, shown at 34 in Figs. 4, 5 and 16, for enclosing the majority of the beam path 25. The beam- bender assembly 26 also includes a BSU 400 beam- switching unit, shown at 36 in Fig. 4, that switches the main laser beam between two separate paths that each leads to one of the cutting stations 28, 30. The beam bender assembly 26 also includes a series of beam- reflecting mirrors, shown at 38-42 in Fig. 4, at 42 in Fig. 5, at 42 and 44 in Fig. 16 and at 46 in Figs. 6 and 7 that direct the beam along each path through the conduits 34 to a point within each of the two cutting stations 28, 30 where laser cutting takes place. An exhaust system, shown at 48 in Figs. 4 and 5, extracts particulate matter and fumes from the class I laser enclosure 32. A dust collector 50 collects the particulate matter extracted from the enclosure 32.

Because the two cutting stations 28, 30 are virtually identical, the following description will refer only to the cutting station generally indicated at 28 in Figs. 4 and 5, i.e., the first station.

A column assembly of the laser system 22, generally indicated at 52 in Figs. 4, 5 and 16, is included at the first cutting station 28. Also located at the first cutting station 28 is a cage holder, generally indicated at 54 in Figs. 9, 10, 14, 16 and 19. The cage holder 54 includes an expanding collet, best shown at 56 in Figs. 10 and 19, that holds CV joint cages such as the cages generally indicated at 58 in Fig. 1 and at 60 in Figs. 2, 3, 9, 10, 14, 15 and 18, for laser window cutting.

The first cutting station 28 also includes a cage-loader assembly, generally indicated at 62 in Figs. 4, 5, 15, 16 and 18, that loads CV joint cages 60 onto the cage holder collet 56; a cage-unloader assembly, generally indicated at 64 in Figs. 4, 5, 15, 16 and 18, that unloads CV joint cages 60 from the cage holder collet 56; and a manipulator, generally indicated at 66 in Figs. 4, 5, and 16, that moves a portion of the beam- bender assembly 26 and the cage holder collet 56 through a laser window-cutting operation.

As shown in Fig. 16, the cage holder 54 is supported on a portion of the manipulator 66 adjacent the beam path 25. The cage holder 54 releasably holds CV joint cages 60 for laser cutting. Certain portions of the manipulator 66 are operatively connected to portions of the laser system 22 and other portions of the manipulator 66 are operatively connected to the cage holder 54. All portions of the manipulator 66 cooperate to direct a laser beam from the laser generator 24 at a wall 67 of the cage 60.

As shown in Figs. 9-14, 16 and 18, the manipulator 66 rotates the cage holder 54 about a rotational "B" axis 68 (Fig. 9) , tips the cage holder 54 about a rotational "A" axis 70 (Fig. 9) and moves the cage holder 54 along horizontal translational "X" and "Y" axes (shown in Fig. 9 at 72 and 74, respectively), to cause the laser beam to cut a series of window-shaped slugs from around the cage wall 67 and to facilitate loading and unloading of CV joint cages 60 on the cage holder collet 56.

As is best shown in Fig. 4, the beam-bender assembly 26 is both optically and physically coupled to the laser generator 24. A beam-converging lens, shown at 76 in Fig. 7, is supported in a beam exit casing 78 of the beam-bender assembly 26 disposed at a lower end of the beam-bender assembly 26 in the laser beam path 25. The lens 76 is held in place by an exteriorly threaded lens retaining ring 77 which engages an interiorly-threaded lens receiving aperture 79. The lens 76 is available from Haas Laser Technologies under the designation #CL115Z-P. Other suitable lenses and mounting hardware may be used in place of the Haas #CL115Z-P.

The series of beam-bending mirrors 38-46 includes a final beam-bending mirror, shown at 46 in Figs. 6 and 7, that is supported on the beam exit casing 78 at a final bending point in the laser beam path 25 between the beam-converging lens 76 and a reflected image-side focal point 80 of the beam-converging lens 76. The final beam bending mirror 46 is available from Haas Laser Technologies under the designation 406778.

As shown in Fig. 7, the beam-bender assembly 26 has an insertion width "W" measured along a ray extending from the image-side focal point 80 of the beam-converging lens 76 along the beam path 25 and through the final beam-bending mirror 46 to the furthest extremity of the beam-bender assembly 26. As shown in Fig. 7, in the preferred embodiment, the furthest extremity along the ray is an upper surface 82 of a nose portion 84 of the beam exit casing 78. The insertion width W of the beam bender assembly 26 determines the size of aperture that the nose portion 84 of the beam- bender assembly 26 may be inserted into to make right- angle, inside-out laser cuts.

As stated above, the final beam-bending mirror 46 is the last bending mirror along the beam path 25 and is disposed down-stream along the beam path 25 from the beam-converging lens 76. Because the beam-converging lens 76 precedes the final beam-bending mirror along the beam path 25, the laser beam is converging as it strikes the final mirror 46. The convergent laser beam generates a considerable amount of thermal energy at the point where it strikes the final beam-bending mirror 46. For this reason, the beam-bender assembly 26 includes a cooling system disposed adjacent the final beam-bending mirror 46.

The cooling system includes a water jacket, generally indicated at 86 in Figs. 6-8. The water jacket 86 is fastened to the beam exit casing 78 in a position close to the final beam-bending mirror 46. The water jacket 86 is positioned close to the final beam- bending mirror 46 to more effectively extract heat energy that the converging laser beam generates as the beam reflects off the beam-bending mirror 46 prior to exiting the beam exit casing 78. The water jacket 86 is formed from a U-shaped metal block 88 dimensioned to fit flush against a portion of the beam exit casing 78 that conforms in exterior dimensions to the dimensions of the inner portion of the U-shaped metal block metal block.

As is best shown in Fig. 8, there are three apertures 90, 92 generally aligned in a row across a top portion of the water jacket 86. The outer two apertures 90 are smaller in diameter than the center aperture 92 and extend into an enclosed water channel 94 disposed inside the water jacket 86. As shown in Fig. 6, pipe elbows 96 are sealingly fixed within the outer apertures 90. Sealingly fixed over respective outer ends of the elbows 96 are flexible water intake 98 and outlet 100 tubes for transporting water to and from the water jacket 86, respectively. One of the outer apertures 90 directs water from the intake tube 98 into the water channel 94 while the other of the outer apertures 90 directs water from the channel 94 into the water outlet tube 100. The water channel 94 provides a path for the cooling water to pass between the two apertures 90 as shown in Fig. 8.

The third (center) water jacket aperture 92 extends completely through the upper portion of the water jacket 86 and is coaxially aligned above a casing aperture 102 disposed through an upper wall of the beam exit casing 78. The casing aperture 102 extends into an interior 104 of the casing 78. An oxygen-in line 106 extends through the third (center) water jacket aperture 92 and is threadedly and sealingly inserted into the casing aperture 102. The oxygen-in line 106 injects oxygen into the casing interior 104 as a coaxial assist gas, i.e., a gas that assists in cutting by acting as an oxidizer to help burn and vaporize metal.

The beam-bender assembly 26 includes a beam exit nozzle, shown at 108 in Figs. 6 and 7. The beam exit nozzle 108 is supported adjacent the final beam- bending mirror 46 in the nose portion 84 of the beam exit casing 78. The exit nozzle 108 has a nozzle aperture 110 disposed concentrically around the laser beam path 25. The nozzle 108 provides the beam exit casing 78 with an exit point for both the converging laser beam and the coaxial assist gas.

The manipulator 66 includes a B-axis rotator, generally indicated at 112 in Figs. 9-12, 14, 16, 18, that rotatably supports the cage holder collet 56 about the rotational "B" axis 68. The "B" axis 68 is the central rotational axis of both the cage holder collet 56 and any cage 60 mounted on the cage holder collet 56. As shown in Figs. 9, 11, 12 and 18, the B-axis rotator 112 includes a drive motor 114, available from Kollmorgen under the designation "Gold Line B-102. " As best shown in Fig. 11, a first pulley 115 is fixed to one end of the drive motor 114. A belt 116 operatively connects the first pulley 115 to a second pulley 117 coaxially fixed to a collet support drum 118 that is rotatably mounted on ball bearings 120. As shown in Fig. 10, a hollow spindle 122 is coaxially and reciprocally mounted within the support drum 118 and is attached at one end to a rotary coupling 121 for receiving compressed air into the spindle 122. The coupling 121 is attached to a cage holder air cylinder 123. The cage holder air cylinder 123 of the present embodiment is available from Bimba under the designation "FO-31-.625-M. " An aft end of the cage holder air cylinder 123 is supported on an outer B-axis rotator casing 126 by a support bracket 128.

The manipulator 66 also includes an A-axis tilt mechanism, generally indicated at 130 in Figs. 9, 11-14, 16 and 18. The A-axis tilt mechanism 130 supports the cage holder 54 and the B-axis rotator 112 on a manipulator platform 131 for tilting motion about the rotational "A" axis 70. The rotational A axis 70 is disposed perpendicular to the rotational B axis 68 to allow the cage holder 54 and an attached cage 60 to be tilted during laser cutting. By tilting the cage 60 around the A axis 70, angles may be cut in circumferential perimeter walls of each cage window, i.e., the "end" walls, shown at 132 in Figs. 2 and 3, that are aligned with the cage circumference and are disposed perpendicular to the B axis 68. In other words, the pitch of the cage window end walls 132 may be controlled by the amount of A axis tilt imparted to the cage holder 54 as the end walls 132 are being cut. As is best shown in Figs. 9 and 13, the tilt mechanism 130 includes a tilt drive motor 134 that drives a cone-drive worm wheel 136. The drive motor 134 of the present embodiment is available from Kollmorgen under the designation "Gold Line B-106." As best shown in Fig. 9, the worm wheel 136 is integrally connected to an axially-extending drive shaft 137 which is bolted to a drive arm 139 which is bolted to one side of the cage holder 54. Bolted to an opposite side of the cage holder 54 is an idler arm 141 which is bolted to an idler shaft 143 which is rotatably supported on the manipulator platform 131. The idler shaft 143 is coupled to a rotary encoder rod 145. The encoder rod 145 of the present embodiment is available from Heidenhain under the designation "426 .0013-10.000" and part number 254.048.66. When actuated, the drive motor 134, drives the cage holder 54 and B axis rotator 112 through a short arc about the A axis 70 with the encoder rod 145 providing feedback to an electronic controller. As shown in Figs. 9 and 14, a damper air cylinder 149 is connected between the cage holder 54 and the manipulator platform 131. The damper air cylinder 149 of the present embodiment is available from Bimba under the designation "F0-09-1.500-1. "

As is best shown in Fig. 9, the A-axis 70 intersects the B-axis 68 at the centroid 138 of a cage 60 mounted on the cage holder collet 56. With the rotational A-axis 70 passing through the cage centroid, a cage 60 mounted on the cage holder 54 will experience a minimum amount of lateral movement for a given amount of tilt.

The manipulator 66 also includes X, Y and Z axis translators, generally indicated at 140, 142 and

144 in Fig. 16. As is best shown in Fig. 16, the X and Y axis translators move the cage holder 54 in the horizontal X and Y axes 72, 74 and the Z axis translator 144 moves a lower reciprocating portion 146 of the laser system column assembly 52 in a vertical Z axis 150.

The X axis translator 140 supports the cage holder 54 for lateral motion along the horizontal translational X axis 72 which is disposed perpendicular to the B axis 68 as shown in Fig 9. The X axis translator 140 includes a horizontally-disposed box- shaped structure that is movably secured on a guideway (not shown) on an upper surface of a stationary, horizontally-disposed rectangular cutting station platform 148.

As shown in Fig. 16, a Y axis translator 142 supports the cage holder 54 for lateral motion along the horizontal translational Y axis 74 which is disposed perpendicular to the X axis 72 as shown in Figs. 9 and 18. In the present embodiment, the X axis translator and Y axis translator are components of a watercooled X- Y table assembly available from Anorad under the part number designation LW10-6. In the Anorad table assembly, the Y axis translator 142 is stacked on top of the X axis translator 140 and is movably secured on a guideway (not shown) and is oriented at a ninety-degree angle to the X axis translator 140. The manipulator platform 131 is stacked on top of and fastened to the Y axis translator 142 portion of the Anorad X-Y table assembly by conventional fastening hardware (not shown) .

As shown in Figs. 5, 16 and 17, the Z axis translator 144 supports a lower reciprocating portion 146 on a vertically oriented guideway 147 of the laser system column assembly 52 for motion along a vertical translational Z axis 150. The Z axis 150 is disposed perpendicular to the X axis 72 and the Y axis 74. As is best shown in Fig. 16, beam bender mirrors 42 and 44 are supported at upper and lower ends of a telescoping conduit section 152 that is surrounded by an accordion- pleated flexible collar 153. The telescoping conduit section 152 allows the Z axis translator 144 to move only the relatively small reciprocating portion 146 of the laser system 22 that includes the beam exit casing 78. This, in turn, allows the majority of the laser system 22 to remain stationary and allows the cutting stations 28, 30 to manipulate their respective beam paths independently.

As is best shown in Fig. 17 the Z axis translator 144 includes a vertically disposed column cylinder, generally indicated at 154. The column cylinder 154 is fixed to an upper surface of a tower flange 158 extending laterally from one side of a laser column support tower 160. The column cylinder 154 of the present embodiment is available from PHD under the designation "AVR 1.375 X 6.5." A nose-positioning ram 162 is supported for driven reciprocal movement within the column cylinder 154 and extends axially downward therefrom. A clevis 164 fixed to a lower end of the nose-positioning ram 162 connects the ram 162 to a rectangular sliding frame 166 of the laser column support tower 160. The sliding frame 166 is slidably mounted on the support tower 160 for reciprocal vertical translational motion on the guideway 147. The support tower 160 and sliding frame 166 are disposed directly above the A axis tilt mechanism 130, the B axis rotator 112 and the X and Y axis translators 140, 142. The lower reciprocating portion 146 of the laser system column assembly 52 is fixed to a support bracket 168 extending laterally outward from the sliding frame. The support bracket 168 supports the lower reciprocating portion 146 of the column assembly 52 and spaces the reciprocating portion 146 from the support tower 160 in the Y direction.

As shown in Fig. 16, a column drive motor 161 is supported in the support tower 160. The column drive motor 161 of the present embodiment is available from Kollmorgen under the designation "B-106." A first gearbelt pulley 163 is coaxially fixed to a drive shaft extending vertically upward from the column drive motor 161. A gearbelt 165 (available from Browning under des. 210L050) operatively connects the first gearbelt pulley 163 to a second gearbelt pulley 167 coaxially fixed to an upper end of a ball screw 169 as shown in Fig. 17. The gearbelt pulleys of the present embodiment are available from Browning under designation 18LG-050. The ball screw 169 is threadedly engaged with a ball nut 171 (available from Star under designation 1512-0-1004) which is bolted to the sliding frame 166. Actuation of the column drive motor 161 causes the ball screw 169 to turn which alternately raises and lowers the sliding frame 166.

As shown in Fig. 16, the cage-loader assembly

62 is disposed adjacent the cage holder 54 to supply blank CV joint cages 60 to the cage holder 54 from outside the class I laser enclosure 32. The cage-loader assembly 62 comprises a load track, shown at 170 in Figs. 4, 5, 15 and 18. The load track 170 has a length extending between an input end 172 and an exit end 174. The input end 172 is disposed adjacent an entrance to the class I laser enclosure 32 and the exit end 174 is disposed adjacent a cage staging nest 176, best shown in Fig. 15. The load track 170 is positioned to allow cages 60 to roll downhill from the load track input end 172 to the staging nest 176 at the load track exit end 174. The load track exit end 174 is positioned to allow cages 60 to drop to a loader pick-up position 178 of the staging nest 176, best shown in Fig. 15.

The cage-loader assembly 62 further includes a loader-gripper-slide, generally indicated at 180 in Figs. 4 and 18. The loader-gripper-slide 180 is disposed below the load track exit end 174 and is laterally displaced from the staging nest 176 and the loader pick-up position 178 in a direction parallel to the Y axis. As best shown in Fig. 18, the loader- gripper-slide 180 comprises a horizontally-disposed loader air cylinder 182 with a load ram 184 extending axially from the loader air cylinder 182, parallel to the Y axis and toward the staging nest 176. The load ram 184 is positioned to be in axial alignment with any cage 60 that is seated in the loader pick-up position 178 in the staging nest 176. In other words, in the loader pick-up position 178, each cage 60 is held in axial alignment with the load ram 184.

The loader air cylinder 182 is bolted to a cylinder support bracket 186 which is, in turn, fastened by well-known means to an upper surface of a generally box-shaped riser platform 188. The riser platform 188 is bolted to the cutting station platform 148. As shown in Fig. 18, a loader cage gripper 190 is supported on the load ram 184 for reciprocal horizontal translational motion relative to the loader air cylinder 182.

As best shown in Fig. 18, the load ram 184 carries the loader cage gripper 190 between the loader pick-up position 178, a verification position 191 disposed slightly axially aft of the loader pick-up position 178 in a direction toward the loader air cylinder 182, and a load position 192. In the load position 192 a mounted cage 60 (a cage 60 mounted on the loader cage gripper 190) is in a position surrounding the cage holder collet 56 and in contact with a datum surface 193. The cage holder 54 load position is at the far left limit of travel along the X axis 72 for the cage holder 54 (as viewed in Fig. 18) . A proximity sensor switch (not shown) is mounted in the staging nest 176 in a position where a cage 60 mounted on the loader cage gripper 190 will disrupt an electromagnetic field of the proximity sensor switch when the cage 60 is moved to the verification position. In other embodiments, any one of a number of suitable proximity sensors, such as mechanically-actuated electrical micro switches, may be used.

As shown in Figs. 5, 15, 16 and 18, a staging nest gate 194 is vertically and slidably disposed between the loader pick-up position 178 and the load position 192. A gate cylinder, shown at 196 in Figs. 15, 16 and 18, is connected between the nest gate 194 and the cutting station platform 148 from below and serves to raise and lower the nest gate 194. The gate cylinder 196 is available from PHD under the designation AVCF 11/8 X 2.00-P-E.

When raised, the staging nest gate 194 is positioned across an opening in the staging nest 176 to retain cages 60 in the loader pick-up position 178 when the cages 60 are dropped from the load track 170. As is best shown in Fig. 15, the staging nest gate 194 has an arcuate cutaway upper edge 198. When the nest gate 194 is fully lowered, the cutaway upper edge 198 provides an opening to allow the loader cage gripper 190 to axially transport a cage 60 past the nest gate 194 to the cage holder collet 56.

A part escapement (not shown) is disposed on an outer wall of the class I laser enclosure 32 adjacent the load track input end 172. At each actuation, the part escapement feeds a single CV joint cage 60 to the loader cage gripper 190 for transfer to the cage holder collet 56. The part escapement includes a sliding door (not shown) that opens intermittently to allow a single cage 60 at a time to enter the enclosure 32 and roll down the load track 170 to the staging nest 176.

As is best shown in Fig. 19, the expanding collet 56 includes three identical collet segments 200. The general shape of the collet 56, with all three segments 200 joined together, is that of a segmented ring or collar. As shown in Fig. 10, the collet segments 200 are held together by an annular collet retainer 202.

The collet retainer 202 includes an axially inboard ring 204 and an axially outboard ring 206. The inboard ring 204 is bolted to the collet support drum 118. A base flange portion 208 of each collet segment 200 is sandwiched between the inner 204 and outer 206 rings. Thus, axially-extending portions 210 of the collet 56 are free to splay radially outward to a cage- engagement position (shown in Fig. 10) and to retract radially inward to a cage-release position. Each collet segment 200 includes a semicircular trough 212 disposed in an outer semi-circumferential surface of each collet segment 200 between the base flange portion 208 and axially-extending portion 210. The troughs 212 produce a reduced section that provides the aforesaid aid in collet segment flexing.

As shown in Figs. 9, 10 and 19, each collet segment 200 has an outer semi-circumferential cage engagement surface 214 for releasably engaging an inner circumferential CV joint cage surface when the collet 56 is in the cage-engagement position. As shown in Figs. 10 and 19, the collet 56 further includes a tapered, frusto-conical central collet aperture 216 coaxially disposed along the B axis 68. Seated within this tapered aperture 216 is a tapered frusto-conical collet driver, shown at 218 in Fig. 10. The conical collet driver 218 is integrally attached to a forward end of the spindle 122. The tapered conical collet driver 218 is supported for reciprocal coaxial movement along the B axis 68 within the collet aperture 216 between an extended and an retracted position. In the extended position the collet driver 218 drives the collet segments 200 radially outward to their engaged positions. In the retracted position the collet driver 218 allows the collet segments 200 to spring back to their disengaged positions. A coil spring 220 is coaxially disposed around the cage holder air cylinder 122 between a base end of the collet driver 218 and a spring seat 222 fixed within the collet support drum 118 as shown in Fig. 10. The spring 220 biases the collet driver 218 and the outer end of the cage holder air cylinder 122 to the extended position. The collet driver 218, spindle 122 and rotary coupling 121 are pneumatically withdrawn to the retracted position by the cage holder air cylinder 123.

In other embodiments, the collet segments 200 may have any one of a number of different configurations as may be suitable for gripping cages of different shapes .

As is best shown in Fig. 19, the cage holder collet 56 has been modified to include three thin seal plates 224 disposed adjacent the outer semi- circumferential cage engagement surface 214. Each seal plate 224 is slidably disposed across one of three gaps 226 disposed between the collet sections 210 to prevent offal, dross and other contaminants from entering the gaps 226 and fouling the collet 56.

A first edge 228 of each seal plate 224 is glued into a slot 230 ground into one of the collet sections 210. A second edge 232 of each seal plate 224, opposite the first edge 228, is slidably disposed on a sliding surface 234 of a rectangular contour ground into a neighboring collet section 210. In other words, each collet section 210 includes a slot 230 fixedly engaging one of the seal plates 224, and a rectangular contour with a sliding surface 234 slidably engaging another of the seal plates 224. Because the seal plates 224 are slidably connected between the collet sections 210, the collet 56 is free to splay radially outward to the cage- engagement position and to retract radially inward to the cage-release position.

As shown in Figs. 10 and 12, the apparatus 20 also includes a collet purge gas delivery assembly 124 that assists in preventing offal, dross and other contaminants from entering the gaps 226 and fouling the collet 56 during laser cutting. The collet purge gas delivery assembly 124 includes the rotary coupling 121, and the spindle 122. A compressed air source (not shown) is connected to the rotary coupling 121 and injects pressurized air through the rotary coupling 121 into the spindle 122. Four holes 227 are disposed at circumferentially spaced locations through a circumferential wall of the spindle 122 adjacent the collet driver 218. The compressed air escapes the spindle 122 by flowing radially outward through the holes 227 and into the cage holder collet 56. The compressed air exits the collet after passing through crevices around the collet sections 210 and the gaps 226 between the collet sections 210. The collet purge gas delivery assembly 124 provides a constant air flow through and around the collet sections that prevents airborne contaminants from entering and lodging in the gaps 226 and crevices. The constant air flow also aids in cooling the spindle 122 and collet 56.

As shown in phantom in Fig. 16, an inclined copper slug slide 236 is disposed below the cage holder 54. An upper end of the slide 236 is disposed directly below the cage holder 54 when the cage holder 54 is aligned with the beam bender assembly 26 for cutting. Window slugs cut from the cage 60 drop from the cage 60, against the slide 236 and slide downwardly.

As is also shown in Fig. 16, a copper slug chute 238 is disposed below a lower end of the slug slide 236. The chute 238 is vertically oriented to guide slugs downward to a slug conveyor belt (not shown) disposed below a lower end of the chute. To withstand the heat of the freshly-cut slugs, the conveyor belt is made of Kevlar®.

The cage unloader assembly 64 is disposed adjacent the cage holder 54 in a position that allows the unloader assembly 64 to remove CV joint cages 60 from the cage holder 54 after the laser window cutting operation is complete. The cage unloader assembly 64 comprises an unload track, shown at 240 in Figs. 4, 5, 15, 16 and 18. The unload track 240 has a length extending between and input end 242 and an exit end 244. The input end 242 of the unload track 240 is supported adjacent the cage holder 54. The exit end 244 is disposed adjacent an outer wall of the enclosure 32 as shown in Fig. 5.

The cage unloader assembly 64 also comprises an unloader-gripper-slide, shown at 246 in Figs. 4, 16 and 18. As is best shown in Fig. 18, the unloader- gripper-slide 246 includes an horizontally-disposed unloader air cylinder 248 with an unload ram 250 extending axially from the unloader air cylinder 248 toward the unload track 240. The loader 182 and unloader 240 air cylinders are available from PHD under the designation NEAG NS41 3/8 x 6 P-E.

The unloader air cylinder 248 is bolted to the cylinder support bracket 186. An unloader cage gripper 252 is mounted to the unload ram 250 for reciprocal translational movement relative to the unloader air cylinder 248. The unload ram 250 carries the unloader cage gripper 252 between positions adjacent the cage holder 54 and the unload track 240.

The unloader-gripper-slide 246 is axially aligned with an unload position of the cage holder 54 shown at 254 in Fig. 18. The cage holder 54 unload position 254 is at the far left limit of travel along the X axis 72 for the cage holder 54 (as viewed in Fig. 18) . The loader cage gripper 190 and the unloader cage gripper 252 are identical to one another. Therefore, the following description of the unloader cage gripper 252 also applies to the loader cage gripper 190. As shown in Figs. 20-22, the unloader cage gripper comprises an SMC gripper 256 available from SMC under part number MHR3-15R. The SMC gripper 256 has three radially-extendable keeper fingers 258 attached by screws to a circular face 260 of the SMC gripper. The fingers 258 are supported on the unloader cage gripper for reciprocal radial movement between retracted and extended positions. The fingers 258 are spring-loaded to the retracted position and are pneumatically driven radially outward by the SMC gripper 256 to engage inner circumferential cage 60 surfaces. The fingers 258 are modified to include beveled notches 261 that correspond to the interior circumference and contours of the cages 60 when the fingers 258 are in the extended position. The keeper fingers 258 also serve as drop guides when the cages 60 are individually lowered into the loader pick-up position 178 of the staging nest 176 from the load track exit end 174.

The SMC gripper 256 includes a cylindrical gripper shaft 262 that is coaxially fastened to a gripper mount 263 by three head cap screws 255. The gripper mount 263 includes a central annular mount shaft

264 and a gripper mount flange 265 that extends radially and integrally outward from the mount shaft 264. As is best shown in Fig. 20, the gripper mounting flange 265 is sandwiched between an annular disk-shaped adapter 266 and a gripper stop ring 268. The adapter 266 is coaxially fixed to an outer end of the unload ram 250 as shown in Figs. 16 and 18. Three springs 270 (Lee part number LC-035E-15) are mounted in spring seats between the adapter 266 and the gripper mounting flange 265, biasing the mounting flange 265 axially away from the adapter 266. As shown in Figs. 20 and 21, a screw 272 is disposed through each of three holes in the stop ring 268 and three corresponding holes in the gripper mounting flange 265 and are threadedly engaged in three threaded holes in the adapter 266. A bushing 274 (Bunting part number P26-8) is coaxially disposed around each screw 272 and is seated, at each of two opposite ends, in the adapter 266 and the stop ring 268, respectively. The three bushings 274 stabilize the unloader cage gripper 252 and limit gripper mounting flange 265 motion to a reciprocal, axial motion between the adapter 266 and the stop ring 268. As shown in Fig. 20, the axial position of the gripper mounting flange 265 between the adapter 266 and the stop ring 268, and, therefore, the axial position of the SMC gripper 256, may be adjusted by advancing or withdrawing three adjustment screws 276. The adjustment screws 276 are circumferentially spaced around the stop ring 268, and are in threaded engagement with three threaded holes in the stop ring 268. The adjustment screws 276 engage an annular face 278 of the gripper mount flange 265 in opposition to the biasing force of the springs 270. When the screws 276 are advanced, they drive the flange 265 axially aft against the biasing force of the springs 270. When the screws 276 are withdrawn, the biasing force of the springs 270 drives the flange 265 forward toward the unload position 254 as shown in Fig. 18.

The electronic controller is a Computer

Numerical Control (CNC) (not shown) operatively connected to the manipulator 66 to control the speed and position of all linear and conventional motors in the window-cutting apparatus 20 with high precision and fast dynamic response. The CNC used in the present embodiment is a Siemens 840C CNC. Other suitable CNCs and other types of motion control systems may be used in place of the Siemens 840C.

In practice, the process of cutting windows in a CV joint cage 60 begins when the CNC signals the escapement to release a cage 60 to roll into the enclosure 32, down the load track 170 and into the staging nest 176. The cage 60 is then released from the staging nest 176 and drops to the loader pick-up position 178 in coaxial alignment with the loader cage gripper 190 of the loader-gripper-slide 180. The CNC signals the loader cylinder 182 to axially advance the loader cage gripper 190 to the loader pick-up position 178. In the loader pick-up position 178 the loader cage gripper grips the cage 60 and pulls the cage 60 axially back to a verification position. In the verification position the cage 60 disrupts the electromagnetic current field of the proximity sensor switch, which, in turn, signals the CNC that a cage 60 is, in fact, ready for installation on the cage holder 54.

Once the CNC verifies the presence of a cage 60 on the loader cage gripper 190, the CNC signals the gate cylinder 196 to lower the staging nest gate 194. The CNC then signals the loader air cylinder 182 to axially advance the load ram 184 and loader cage gripper

190 past the lowered gate 194 to the load position 192 with the mounted cage 60 disposed flush against the datum surface 193 and surrounding the cage holder collet 56. At this point the CNC signals the cage holder 54 to engage the cage 60 and signals the loader cage gripper 190 to release the cage 60 and axially retract. Once the loader cage gripper 190 has retracted, the CNC signals the gate cylinder 196 to raise the staging nest gate 194.

In the load position 192, the cage holder 54 is at the far left limit of its travel along the X axis 72 as is best shown by the position of the cage 60 in Fig. 18.

The cage holder 54 moves along the X axis 72 and the Y axis 74 to a cutting position 280 between the load 192 and unload 254 positions of the cage 60 as shown in Fig. 18.

The CNC then signals the lower reciprocating portion 146 of the laser system column assembly 52 to drop down along the Z axis 150 to a position where the nose portion 84 of the beam-bender assembly 26 is axially aligned with the cage 60 and the cage holder 54. The CNC then signals the cage holder 54 to axially advance the cage 60 toward the nose 84 and into the cutting position 280 where the cage 60 surrounds the nose portion 84 of the beam-bender assembly 26. In the cutting position 280 the beam-bender nozzle 108 is aiming downward at, and the converging lens 76 is focusing on, a lower portion of an inner circumferential 282 surface of the cage wall 67. The laser nozzle 108 is initially aimed at a central portion of the region where the cage window is to be cut to keep the area of extra burn, i.e., the initial "burn-through" area, away from where the window perimeter walls will be. In other words, the burn-through area is confined to the interior of each window slug where it will not affect the finish quality of the window perimeter walls. Before the CNC signals the laser generator 24 to energize and/or signals the beam-switching unit 36 to direct the beam along the beam path 25 leading to the first cutting station 28, cooling water is channeled through the water jacket 86. Cooling water continues to flow through the water jacket 86 whenever the laser is firing. When the CNC signals the laser generator 24 to energize, a laser beam issues from the generator 24. If the beam-switching unit 36 in the proper position, the beam is reflected along the path 25 to the first cutting station 28 by the series of beam-bending mirrors 38-46 supported in the beam-bender assembly 26. Prior to reflecting off the final beam bending mirror, the beam passes through the converging lens 76. The laser beam leaves the converging lens 76 and reflects off the final beam-bending mirror. The final beam-bending mirror directs the converging beam out the exit nozzle 108. The approximate point of beam convergence, i.e., the reflected converging lens image-side focal point 80, is located at the cage wall 67 being cut.

As the laser beam is burning a hole through the cage wall 67, and whenever the beam is energized and being directed to the first cutting station 28, oxygen is being fed into the beam exit casing 78 through the oxygen intake tube 98. The oxygen exits the casing 78 through the beam exit nozzle 108 where it serves as an assist gas, i.e. an oxidizing agent that helps vaporize and burn-away the metal.

Once the laser beam has burned through the cage wall 67, the laser beam remains stationary as the CNC executes a four or five-axis interpolated motion control path to complete the cutting of one window in the cage 60. In other words, the CNC signals the B axis rotator 112, the A axis tilt mechanism 130 and the X and Y axis translators 140, 142 to move the cage holder 54 along a path that causes the stationary laser beam to cut a window-shaped slug from the cage wall 67. The resulting windows (and window slugs) have a generally rectangular shape with rounded corners.

To make circumferential cuts in the cage wall 67, i.e., to cut the window end walls 132, the CNC commands the B axis rotator 112 to rotate the cage holder 54 and cage 60 around the B axis 68 and/or commands the X axis translator 140 to move the cage holder 54 and in a linear motion along the X axis 72.

To make cuts in the cage wall 67 that are perpendicular to the circumferential cuts, i.e., to cut window side walls, shown at 284 in Figs. 2 and 3, the CNC commands the Y axis translator 142 to move the cage holder 54 and cage 60 in a direction parallel to the B axis 68.

To control the angle of the side walls 284, and therefore the profile of ribs 286 formed between adjacent windows, the CNC adjusts the cutting angle of the laser beam by rotating the cage holder collet 56 and cage 60 around the B axis 68 and translating the collet 56 and cage 60 along the X axis 72. If, for example, a cage such as the cage shown at 58 in Fig. 1, is pre- positioned in preparation for cutting each window side wall 284' solely by moving the cage 58 laterally along the X axis 72 with no B axis 68 rotation, opposing window side walls 284' will be cut parallel to one another, resulting in ribs 286' with generally trapezoidical rib profiles. If, however, a cage such as the cage shown at 60 in Figs. 2 and 3, is pre-positioned in preparation for cutting each window side wall solely by rotating the cage 60 around the B axis 68 with no X axis 72 translation, the resulting side walls 284 will extend radially through the cage walls, resulting in ribs 286 with generally rectangular rib profiles. In other words, as shown in Figs. 2 and 3, opposing window side walls 284 will be non-parallel, diverging radially outwards .

During cutting, the laser beam is aimed downward from within the cage 60 toward a portion of the cage wall 67 disposed below the beam-bender nozzle 108. This allows the window slugs to drop free to the slug slide 236, slide down the slug slide 236 and fall through the slug chute 238 onto the slug conveyor belt (not shown) .

After each window is cut, the CNC either signals the laser generator 24 to de-energize, signals a shutter mechanism (not shown) of the laser system 22 to re-direct the laser beam to a beam dump (not shown) , or signals the beam-switching unit 36 to re-direct the beam from the first cutting station 28 to the second cutting station 30. With the laser off, the CNC signals the B axis rotator 112 to rotate the cage holder 54 and cage 60 around the B axis 68 until the nozzle 108 is aimed at a portion of the inner circumferential surface of the cage wall 67 where an additional cage window is to be cut. The same cutting and manipulating process is then carried out for each successive window, until a desired number of window-shaped slugs have been cut from around the cage wall 67.

When cutting is complete, the CNC signals the Y axis translator 142 to axially withdraw the cage 60 from around the beam-bender nose portion 84. The CNC then signals the Z axis translator 144 to lift the lower reciprocating portion 146 of the laser system column assembly 52 upward.

To discharge the finished cage 60, the CNC signals the X axis translator 140 to move the cage holder 54 and cage 60 laterally along the X axis 72 to the unload position 254 where the cage 60 lies in axial alignment with the unloader cage gripper 252 of the unloader-gripper-slide 246. The CNC then signals the unloader cage gripper 252 to advance toward and grip the cage 60. Once the unloader cage gripper 252 has gripped the cage 60, the cage holder 54 releases the cage 60 and the CNC signals the unloader cage gripper 252 to axially withdraw, transporting the cage 60 to a position above the unload track 240. The unloader cage gripper 252 then releases the finished cage 60 and allows the cage 60 to drop to and roll down the unload track 240 and out of the enclosure 32.

Set forth below is a documented listing of a part program created for the Siemens 840C CNC that operates the first cutting station 28 of the apparatus 20 described above. The program directs the CNC to cut windows in a constant-velocity joint cage 60 as is generally described above. In addition, the program directs the CNC to cut cage windows with both clockwise and counterclockwise cutting paths .

This reversal of cutting paths helps to minimize nozzle wear and dross accumulations. The nozzle wears most severely on a trailing edge of the nozzle when the laser is initially cutting through, i.e., penetrating a cage wall, and when the laser first accelerates out of an initial "burn-through" position. Consequently, making alternating clockwise and counterclockwise cuts helps to distribute the nozzle wear on opposite edges of the nozzle.

Path reversal also helps to identify and differentiate between different CV joint cages. The direction that a cage has been cut is discernable on the finished cage by observing the position of witness marks that are left at the cutting start and end points. By programming the CNC to cut the windows of each type of cage in a pre-selected fashion, the cages may later be distinguished from one another by the positions of the witness marks.

Within the following documented listing, parenthetical statements are explanatory rather than executable steps. Following the listing are further explanations of various steps and series of steps found in the listing.

Transtec Advanced Machine Division - CV Joint Laser Cutting System

Documented Listing: For Siemens 840C CNC Control

1. %MPF1234

2. (LOGFILE NAME IS: G34LR71.LOG)

3. (START POSITION IS: X=-3 Y=-2 Z=+0.7262)

4. Rl=-3 R2=-2 R3=+0.7262 R5= 8 R704= 16.65 5. (THE PREVIOUS THREE LINES ARE A REQUIREMENT TO THE FORMAT OF THIS TEMPLATE)

6. (DO NOT TRANSLATE OR CHANGE THOSE LINES)

7. (G55 IS OFFSET FOR CUTTING - X0 Y0 Z0 SHOULD BE BOTTOM DEAD CENTER) 8. (PARAMETER RIO IS DESIGNATED FOR WINDOW WIDTH TRIMMING - BOTH HEADS.)

9. (NOTE: RIO SHOULD BE SMALL <+/-0.31MM)

10. N0010 R50 = RIO * RIO 11. R51=0.31*0.31

12. R50 R51 K100 (IF RIO <> 0.31 STOP ELSE GOTO N100)

13. MOO

14. (VALUE RIO IS TOO BIG!)

15. K-10 (LOOP UNTIL FIXED) 16. N0100M12 (SELECT CW)

17. M68 (BEAM ON)

18. L182 (MOVE TO SAFE POSITION)

19. N1000 L181 (CALL SUBROUTINE TO UNLOAD)

20. M01 (OPTIONAL STOP) 21. G01 G90 G64 Yl=-25 Zl=30 F10000

22. G01 G90 Xl=70 Bl=120

23. G02 G17 Xl=70 Yl=-25 Bl=240 J-10 F5000

24. G01 G90 Xl=130 B1=0 F10000

25. G01 G90 Z1=R107 26. LI80 (CALL SUBROUTINE TO LOAD)

27. G55 G64 G71 (SELECT WORK COORDINATE SYSTEM)

28. GOO G90 G640 X1=0 Yl=-30 Zl=110 A1=0 Bl=-0 F3000(MOVE TO 1ST WINDOW)

29. GOO G90 G640 Yl=-30 Zl=15 (MOVE TO 1ST WINDOW) 30. GOO G90 G600 X1=R1 Y1=R2 Z1=R3 A1=0 (START POSITION - 1ST WINDOW)

31. M40 (WAIT)

32. M61 (LO GAS PRESSURE ON - EXPEDITE)

33. M14 (SELECT BEAM) 34. M64 (LO PRESSURE GAS ON - HOLD)

35. R4= 0 (PRESET WINDOW NUMBER)

36. N1100 R4=R4+1 (INCREMENT WINDOW NUMBER)

37. R4 Kl KlllO K2 K1120 K3 K1130 K4 K1140 K5 K1150 K6 K1160 38. K9000 39. NlllO GOl G90 G600 X1=R1 Y1=R2 Z1=R3 A1=0 B1=0 F20000 (START POSITION - 1ST WINDOW)

40. R0= 0 + RIO (WIDTH COMP. + WIDTH OFFSET)

41. K1200 42. N1120 GOl G90 G600 X1=R1 Yl=R2+0 Z1=R3 A1=0 Bl=60 F20000 (START POSITION - 2ND WINDOW + HEIGHT COMP.)

43. R0= 0 + RIO (WIDTH COMP. + WIDTH OFFSET)

44. K1200

45. N1130 GOl G90 G600 X1=R1 Yl=R2+0 Z1=R3 A1=0 Bl=120 F20000 (START POSITION - 3RD WINDOW + HEIGHT COMP.)

46. R0= 0 + RIO (WIDTH COMP. + WIDTH OFFSET)

47. K1200

48. N1140 GOl G90 G600 X1=R1 Yl=R2+0 Z1=R3 A1=0 Bl=180 F20000 (START POSITION - 4TH WINDOW + HEIGHT COMP.) 49. R0= 0 + RIO (WIDTH COMP. + WIDTH OFFSET)

50. K1200

51. N1150 GOl G90 G600 X1=-R1 Yl=R2+0 Z1=R3 A1=0 Bl=240+R5 F20000 (START POSITION - 5TH WINDOW + HEIGHT COMP . ) 52. R0= 0 + RIO (WIDTH COMP. + WIDTH OFFSET)

53. K1201

54. N1160 GOl G90 G600 X1=-R1 Yl=R2+0 Z1=R3 A1=0 Bl=300+R5 F20000 (START POSITION - 6TH WINDOW + HEIGHT COMP . ) 55. R0= 0 + RIO (WIDTH COMP. + WIDTH OFFSET)

56. K1201

57. N1200

58. /M01 (OPTIONAL STOP)

59. M07 60. G01G17G64G91 Xl=-3.5781 Yl=+1.9514 Zl=+0.2588 Al=- 0.1500 F2400

61 . R50= R5

62 . R51= -R0 -5 . 7299

63 . G01G17 Xl=-1 . 3011 Yl=+0 . 7096 Zl=+0 . 2447 64 . G01G17 Xl=-0 . 9759 Yl=+0 . 5322 Zl=+0 . 2389 65. G01G17 Xl=-0.6506 Yl=+0.3548 Zl=+0.1865

66. G02G17 Xl=-0.3909 Yl=+0.3070 Zl=+0.1591 1+0.7182 J+1.3168

67. G02G17 Xl=-0.3127 Yl=+0.5320 Zl=+0.1585 1+1.1091 J+1.0098

68. G02G17 Xl=-0.0782 Yl=+0.4779 Zl=+0.0766 1+1.4218 J+0.4779

69. G02G17 Xl=+0.5009 Yl=+2.4000 Zl=+0.1770 1+6.0000 F2400 70. G02G17 Xl=+2.8837 Yl=+2.9999 Zl=-0.1412 1+5.4990 J- 2.4000

71. G02G17 Xl=+2.6153 Yl=+0.6000 Zl=-0.3524 1+2.6153 J- 5.3999

72. G02G18 Xl=+8.5750 Zl=+0.0000 Bl= R50 1+4.2875 K+27.117 F1633

73. G02G17 Xl=+2.6153 Yl=-0.6000 Zl=+0.3524 J-6.0000 F2400

74. G02G17 Xl=+2.8837 Yl=-2.9999 Zl=+0.1412 1-2.6153 J- 5.3999 75. G02G17 Xl=+0.5009 Yl=-2.4000 Zl=-0.17701-5.4990 J- 2.4000

76. G02G19 Yl= R51 Zl=+0.0000 J-2.8649 K+26.800 Al=+0.3000 F2400

77. G02G17 Xl=-0.5009 Yl=-2.4000 Zl=+0.1770 1-6.0000 F2400

78. G02G17 Xl=-2.8837 Yl=-2.9999 Zl=-0.1412 J+2.4000 I- 5.4990

79. G02G17 Xl=-2.6153 Yl=-0.6000 Zl=-0.3524 J+5.3999 I- 2.6153 80. G03G18 Xl=-8.5750 Zl=+0.0000 Bl=-R50 1-4.2875 K+27.117 F1633

81. G02G17 Xl=-2.6153 Yl=+0.6000 Zl=+0.3524 J+6.0000 F2400

82. G02G17 Xl=-2.8837 Yl=+2.9999 Zl=+0.1412 J+5.3999 1+2.6153 83. G02G17 Xl=-0.5009 Yl=+2.4000 Zl=-0.1770 J+2.4000 1+5.4990

84. G03G19 Yl=-R51 Zl=+0.0000 J+2.8649 K+26.800 Al=- 0.3000 F2400 85. M08 G01G17 Xl=+1.5000 Yl=+3.0000 Zl=-0.0452

86. K-1100

87. N1201

88. /M01 (OPTIONAL STOP)

89. M07 90. G01G17G64G91 Xl=+3.5781 Yl=+1.9514 Zl=+0.2588 Al=- 0.1500 F2400

91. R50= -R5

92. R51= -R0 -5.7299

93. G01G17 Xl=+1.3011 Yl=+0.7096 Zl=+0.2447 94. G01G17 Xl=+0.9759 Yl=+0.5322 Zl=+0.2389

95. G01G17 Xl=+0.6506 Yl=+0.3548 Zl=+0.1865

96. G03G17 Xl=+0.3909 Yl=+0.3070 Zl=+0.1591 1-0.7182 J+1.3168

97. G03G17 Xl=+0.3127 Yl=+0.5320 Zl=+0.1585 1-1.1091 J+1.0098

98. G03G17 Xl=+0.0782 Yl=+0.4779 Zl=+0.0766 1-1.4218 J+0.4779

99. G03G17 Xl=-0.5009 Yl=+2.4000 Zl=+0.1770 1-6.0000 F2400 100. G03G17 Xl=-2.8837 Yl=+2.9999 Zl=-0.1412 1-5.4990 J- 2.4000

101. G03G17 Xl=-2.6153 Yl=+0.6000 Zl=-0.3524 1-2.6153 J- 5.3999

102. G03G18 Xl=-8.5750 Zl=+0.0000 Bl= R50 1-4.2875 K+27.117 F1633

103. G03G17 Xl=-2.6153 Yl=-0.6000 Zl=+0.3524 J-6.0000 F2400

104. G03G17 Xl=-2.8837 Yl=-2.9999 Zl=+0.1412 1+2.6153 J- 5.3999 105. G03G17 Xl=-0.5009 Yl=-2.4000 Zl=-0.1770 1+5.4990 J- 2.4000

106. G02G19 Yl= R51 Zl=+0.0000 J-2.8649 K+26.800 Al=+0.3000 F2400 107. G03G17 Xl=+0.5009 Yl=-2.4000 Zl=+0.1770 1+6.0000 F2400

108. G03G17 Xl=+2.8837 Yl=-2.9999 Zl=-0.1412 J+2.4000 1+5.4990

109. G03G17 Xl=+2.6153 Yl=-0.6000 Zl=-0.3524 J+5.3999 1+2.6153

110. G02G18 Xl=+8.5750 Zl=+0.0000 Bl=-R50 1+4.2875 K+27.117 F1633

111. G03G17 Xl=+2.6153 Yl=+0.6000 Zl=+0.3524 J+6.0000 F2400 112. G03G17 Xl=+2.8837 Yl=+2.9999 Zl=+0.1412 J+5.3999 I- 2.6153

113. G03G17 Xl=+0.5009 Yl=+2.4000 Zl=-0.1770 J+2.4000 I- 5.4990

114. G03G19 Yl=-R51 Zl=+0.0000 J+2.8649 K+26.800 Al=- 0.3000 F2400

115. M08 G01G17 Xl=-1.5000 Yl=+3.0000 Zl=-0.0452

116. K-1100

117. N9000 M41 (RELEASE PROCESS 2)

118. M63 (GAS OFF) 119. GOO G90 G640 X1=0 Yl=-30 Zl=15 B1=0 F10000(SAFE POSITION MOVE)

120. GOO G90 G600 Yl=-30 Zl=100 F3000(SAFE POSITION MOVE)

121. GOO G54 G90 G640 X1=R105 Y1=R106 Z1=R107 A1=R108 B1=R109 (MOVE TO UNLOAD POSITION)

122. K-1000 (LOOP TO N1000) 123. M02 (END PROG)

The part program set forth above is illustrative of a program for cutting windows in constant-velocity joint cages having six windows rather than the five shown in Figs. 2 and 3. This program takes care of the automation relating to parts handling and cuts the cage with both clockwise and counterclockwise cutting paths to minimize nozzle wear, dross accumulations and to identify the component.

Lines 1-18 of the documented listing initialize the apparatus 20 and are executed only once at the beginning of a continuous machine cycle.

In line 19, "L181" is a command which calls a subroutine which activates the mechanisms necessary to unload a cage 60 from the cage holder 54. At the beginning of a cycle this command simply ensures that no cage 60 is currently loaded.

In line 20, "M01" is an optional stop which allows the window cutting process to be selectively stopped before any machine motion takes place. It also selectively stops the cutting process after unloading each finished component.

Lines 21-26 cause the X and Y axis translators 140, 142, to move the cage holder 54 to the load position 192 but also move in such a way that a nozzle brush, shown at 288 in Fig. 14, sweeps a lower tip of the nozzle 108 during this motion. The "LI" command is a subroutine call which activates the mechanisms necessary to load the cage 60 onto the cage holder 54.

Lines 27-31 cause the X and Y translators to move the cage holder 54 and cage 60 from the load position 192 to the cutting position 280, i.e., the correct position to begin laser cutting. In this case, the cage 60 and nozzle 108 are positioned so that the nozzle 108 cuts the windows from a position inside the cage 60. In this position the "M40" command causes the process to wait until the second cutting station 30 has finished with the laser beam and until the BSU 400 beam- switching unit 36 has directed the beam along the beam path 25 leading to the first station 28.

Lines 32-35 initialize the window-cutting apparatus 20 for cutting on the first cutting station

28. The assist gas is turned on and the beam switching unit 36 is activated to direct the laser beam to the first cutting station 28.

Lines 36-56 is a sequence that begins a loop in the program execution which repeats (six times in this case) for each window that needs to be cut. For each window the start position may be uniquely defined and the direction of cut selected. Additionally, the exact window width for each window can be adjusted to compensate for thermal expansion of the component which occurs during processing. In this case, the first 4 windows are cut in a counterclockwise fashion whereas the last 2 windows are cut counterclockwise.

Lines 57-86 is a sequence of commands that cause the Z axis translator 144 to move the lower reciprocating portion 146 of the laser system column assembly 52, and that cause the X axis and Y axis translators 140, 142, the B axis rotator and the A axis tilt mechanism 130 to move the cage holder 54 in such a way as to cause the laser beam to cut one window in a clockwise fashion. Lines 87-116 is a sequence of axis moves that is executed to cut one window in a counterclockwise fashion. (The path is identical to the clockwise path except that the X axis commands are reversed.)

In lines 117-121 the M41 command allows the second laser cutting station 30 to proceed if it is currently waiting. The assist gas is then turned off and the X and Y axis translators 140, 142 move the cage holder in a safe fashion to the unload position 254.

Line 122 causes the program sequence to return to Line 19. where the subroutine to unload the cage 60 is called and executed. The process then repeats for another cage 60.

Because the final beam-bending mirror is disposed between the beam-converging lens 76 and its image-side focal point 80, the final beam-bending mirror may be positioned close to the focal point 80. Because the final beam-bending mirror is positioned close to the focal point 80, the beam bender insertion width W is reduced sufficiently to fit within a confined space (such as a CV joint cage interior) and make right-angle laser cuts. This allows the laser to cut windows in a CV joint cage 60 from inside-out rather than outside-in without having to reduce the beam-converging lens 76 focal length.

By using an apparatus constructed according to the present invention in executing the method of the present invention, the manufacture of alternative cage geometries is made commercially practicable. Such alternative geometries include odd numbers of cage windows and generally rectangular window rib profiles as with the cage 60 best shown in Figs. 2 and 3. One advantage of a more rectangular rib profile, as shown at 286 in Fig. 3, is that it optimizes the relationship between the strength of the ribs 286 and the available clearance between the ribs 286 and the ball bearings disposed between the ribs 286. A cage having rectangular ribs 286 may therefore be designed to be stronger, lighter or both.

I intend the above description to illustrate embodiments of the present invention by using descriptive rather than limiting words. Obviously, there are many ways that one might modify these embodiments while remaining within the scope of the claims. In other words, there are many other ways that one may practice the present invention without exceeding the scope of the claims.

Claims

We claim:

1. An apparatus for cutting windows in constant-velocity (CV) joint cages and the like, said apparatus comprising; a laser generator that emits a laser beam along a laser beam path when energized, a cage holder disposed adjacent said beam path to releasably hold an annular object such as a CV joint cage for said laser beam to cut; and a manipulator operatively connected to at least one of said laser generator and said cage holder to direct a laser beam from said laser generator at a wall of the object and to manipulate at least one of said laser beam and said cage holder to cause the laser beam to cut a window through the object wall that will fully surround a bearing supported therein.

2. An apparatus as defined in claim 1 and further comprising a beam-bender assembly optically coupled to said laser generator and defining a final portion of said beam path, said beam-bender assembly including: a beam exit casing; a final beam bending mirror supported on said casing at a bending point in said laser beam path; and a beam-converging lens supported on said casing in said laser beam path; said beam-bender assembly having an insertion width measured along a ray extending from an image-side focal point of said beam-converging lens along said beam path and through said final beam-bending mirror to the furthest extremity of the beam-bender assembly; said final beam-bending mirror disposed between said beam-converging lens and said focal point to reduce said insertion width by positioning said final beam-bending mirror close to said focal point thereby enabling said beam-bender to make right-angle laser cuts from within a confined space such as a CV joint cage interior.

3. An apparatus as defined in claim 2 in which said beam-bender assembly includes a cooling system disposed adjacent said final beam-bending mirror.

4. An apparatus as defined in claim 1 in which said manipulator includes a B-axis rotator rotatably supporting said cage holder about a central rotational B axis of said cage holder.

5. An apparatus as defined in claim 4 in which said manipulator includes: an X axis translator supporting said cage holder for lateral motion along a horizontal translational X axis disposed perpendicular to said B axis ; and a Y axis translator supporting said cage holder for lateral motion along a horizontal translational Y axis disposed perpendicular to said X axis.

6. An apparatus as defined in claim 5 in which said manipulator includes an A-axis tilt mechanism supporting said cage holder for tilting motion about a rotational A axis disposed perpendicular to said rotational B axis.

7. An apparatus as defined in claim 6 in which said A-axis intersects said B-axis at a point where the centroid of a CV joint cage would be located when the cage is mounted on said cage holder.

8. An apparatus as defined in claim 2 in which said manipulator includes a Z-axis translator supporting said beam-bender nose portion for motion along a vertical translational Z axis disposed perpendicular to said X and Y axes.

9. An apparatus as defined in claim 1 in which said laser generator comprises a C0₂ laser.

10. An apparatus as defined in claim 1 in which said cage holder comprises: a radially-segmented collet including at least two collet segments; each said collet segment having an outer circumferential cage engagement surface; each said collet segment movably supported to splay radially outward to a cage-engagement position and to retract radially inward to a cage-release position.

11. An apparatus as defined in claim 10 in which said collet includes a central collet aperture coaxially disposed along said B axis and in which said cage holder comprises a tapered collet driver supported for reciprocal coaxial movement along said B axis within said collet aperture between an extended and a retracted position.

12. An apparatus as defined in claim 10 in which said collet comprises gaps between said collet segments when said collet segments are splayed out of said cage-release position and in which said cage holder includes at least two seal plates slidably supported on said collet segments, each said seal plate spanning a portion of one of said gaps when said collet segments are splayed out of said cage-release position.

13. An apparatus as defined in claim 10 further including a collet purge gas delivery assembly supported on said manipulator to force gas through the cage holder collet to prevent contaminants from fouling the collet during laser cutting.

14. An apparatus as defined in claim 13 in which said collet purge gas delivery assembly includes a spindle supported on said manipulator adjacent said collet, said spindle having a hollow center and at least one gas escape orifice for delivering pressurized gas to said collet.

15. An apparatus as defined in claim 14 in which said collet purge gas delivery assembly includes a rotary coupling supported on said spindle to receive compressed air into said spindle for delivery to said collet.

16. An apparatus as defined in claim 1 further including an electronic controller operatively connected to said manipulator.

17. An apparatus for cutting windows in constant-velocity joint cages, said apparatus comprising; a laser generator that emits a laser beam along a laser beam path when energized, a cage holder disposed adjacent said beam path to releasably hold a CV joint cage for said laser beam to cut, said cage holder having a central rotational B axis ; and a manipulator operatively connected to at least one of said laser generator and said cage holder to direct a laser beam at a wall of the cage and to manipulate at least one of said laser beam and said cage holder to cause the laser beam to cut a window in the cage wall, said window defined by at least one window perimeter wall, said manipulator including a tilt mechanism connected to said cage holder to adjustably tilt the cage holder about at least one axis to control the pitch of said window perimeter wall.

18. An apparatus as defined in claim 17 further comprising a beam-bender assembly optically coupled to said laser generator and defining a final portion of said beam path, said beam-bender assembly including: a beam exit casing; a final beam bending mirror supported on said casing at a bending point in said laser beam path; and a beam-converging lens supported on said casing in said laser beam path; said beam-bender assembly having an insertion width measured along a ray extending from an image-side focal point of said beam-converging lens along said beam path and through said final beam-bending mirror to the furthest extremity of the beam-bender assembly.

19. An apparatus as defined in claim 18 in which said final beam-bending mirror is disposed between said beam-converging lens and said image-side focal point.

20. An apparatus for cutting windows in constant-velocity (CV) joint cages and the like, said apparatus comprising; a cutter; a cage holder disposed adjacent said beam path to releasably hold an annular object such as a CV joint cage for said cutter to cut; a manipulator operatively connected to at least one of said cutter and said cage holder to direct said cutter through a wall of the object and to manipulate at least one of said cutter and said cage holder to cause the cutter to cut a window through the object wall; said cage holder including a collet comprising at least two collet segments outwardly splayable from a release position to an engagement position, said collet comprising gaps between said collet segments when said collet segments are splayed out of said cage-release position; and said cage holder including at least two seal plates slidably supported on said collet segments, each said seal plate spanning a portion of one of said gaps when said collet segments are splayed out of said cage- release position to prevent offal, dross and other contaminants from entering the gaps and fouling the collet.

21. An apparatus as defined in claim 20 in which a first edge of each said seal plate is fixed to one of said collet segments and a second edge of each seal plate is slidably disposed on a sliding surface of another of said collet segments.

22. A method for cutting a window through a circumferential wall of an annular object such as a CV joint cage, using an apparatus comprising a laser generator that emits a laser beam along a laser beam path when energized, a cage holder disposed adjacent the beam path, a manipulator operatively connected to at least one of the laser generator and cage holder, and a beam-bender assembly optically coupled to the laser generator and defining a final portion of the beam path, the beam bender assembly having a nose portion that houses a final beam-bending mirror and a beam exit nozzle; said method comprising the steps of: moving at least one of the cage holder and the beam-bender assembly to position the beam-bender nose where the nozzle is aiming at a portion of the wall of the annular object where a window is to be cut; causing a laser beam to issue from the nozzle and to burn a hole through the object wall; manipulating at least one of the laser and the cage holder to cause the laser beam to cut a window- shaped slug from the object wall; causing the laser beam to stop issuing from the nozzle; moving at least one of the cage holder and the beam-bender assembly to reposition the beam-bender nose away from the object.

23. A method as defined in claim 22 including the additional step of injecting a coaxial assist gas into the nose portion of the beam bender assembly thereby forcing the gas to exit the casing through the beam exit nozzle during lasing.

24. A method as defined in claim 22 including the additional step of purging the cage holder at least during said step of manipulating at least one of the laser and the cage holder, said purging step included to prevent airborne contaminants from fouling the cage holder during cutting.

25. A method as defined in claim 24 in which said purging step includes the step of causing air to flow through the cage holder.

26. A method as defined in claim 22 in which said step of moving at least one of the cage holder and the beam-bender assembly to position the beam-bender nose where the nozzle is aiming at a portion of the object wall includes the step of positioning the nose portion of the beam-bender assembly inside the object with the nozzle aiming at an interior surface of the circumferential wall of the object.

27. A method as defined in claim 26 in which said manipulating step includes the step of aiming the laser beam downward toward an interior surface of a circumferential wall portion disposed below the beam- bender nozzle.

28. A method as defined in claim 26 in which said step of moving at least one of the cage holder and the laser beam-bender to place the beam-bender nose inside the annular object, includes the step of positioning the beam-bender nozzle to aim at an interior portion of the window to be cut.

29. A method as defined in claim 22 in which said manipulating step includes the step of moving at least one of the cage holder and the beam-bender assembly along a computer numerically controlled multi- axis interpolated motion control path.

30. A method as defined in claim 22 in which said manipulating step includes the steps of: forming a circumferentially-aligned window end wall disposed perpendicular to and equidistant from a central rotational B axis of the object and cage holder; and forming a window side wall perpendicular to the end wall and parallel to the B axis.

31. A method as defined in claim 30 in which said step of forming a window end wall includes the step of rotating the cage holder around the B axis.

32. A method as defined in claim 30 in which said step of forming a window end wall includes the step of translating the cage holder along a horizontal X axis perpendicular to the B axis.

33. A method as defined in claim 30 in which said step of forming a window end wall includes the step of rotating the cage holder around the B axis and translating the cage holder along a horizontal X axis perpendicular to the B axis.

34. A method as defined in claim 30 in which said step of forming a window end wall includes the step of adjusting the pitch of the window end wall by tipping the cage holder about a horizontal A axis, perpendicular to the B axis.

35. A method as defined in claim 30 in which said step of forming a window side wall includes the step of moving the cage holder in a direction parallel to the B axis.

36. A method as defined in claim 35 in which said step of forming a window side wall includes the step of adjusting the pitch of the window side wall by rotating the cage holder around the B axis.

37. A method as defined in claim 36 in which said step of adjusting the pitch of a window side wall includes the additional step of translating the cage holder along a horizontal X axis perpendicular to the B axis prior to said step of forming a window side wall.

38. A method as defined in claim 30 including the additional step of rotating the cage holder around the B axis to aim the nozzle at a portion of an inner circumferential surface of the object wall where an additional window is to be cut, said additional step accomplished prior to said step of moving at least one of the cage holder and the laser beam-bender to reposition the beam-bender nose away from the object.

39. A method as defined in claim 38 in which said steps of causing a laser beam to issue from the nozzle, manipulating at least one of the laser and the cage holder to cause the laser beam to cut a window- shaped slug from the object wall, causing the laser beam to stop issuing from the nozzle, and rotating the cage holder around the cage central axis to aim the nozzle at a portion of the inner circumferential surface of the object wall where an additional window is to be cut, are repeated until a desired number of window-shaped slugs have been cut from around the circumferential wall of the object.