Method and Apparatus For Multi-Axis Waterjet/Abrasivejet Cutting

Abstract

A multi-axis waterjet cutting system is disclosed which eliminates high-pressure tubing coils in the area adjacent the waterjet system's cutting head and isolates critical system components from the backsplash of the cutting process. A high-pressure swivel is combined with an on/off valve arrangement in such a way that these components are closely adjacent the cutting head and rotate therewith, and are substantially shielded from waterjet back-splash. The cutting head and the swivel/valve combination are rotated about the cutting head's final axis of rotation (e.g., the A-axis) by a drive mechanism substantially shielded by the structure which rotates the cutting head associated with a prior axis of rotation (e.g., the C-axis). By eliminating high pressure tubing coils, the disclosed system reduces the clearance needed for manipulation of the cutting head around the workpiece.

I claim: 
     
         1 . A waterjet cutting system comprising:
 a cutting head;   structure for selectively and controllably translating and rotating the cutting head with respect to a plurality of axes so as to permit the cutting head to approach a workpiece from a desired direction, there being at least two axes of rotation of which rotation about one axis of rotation does not change the position of the other axis of rotation;   a high-pressure water-conducting swivel in serial fluidic communication with an on/off valve, and positioned with said valve in such a way that the swivel and valve are closely adjacent the cutting head for translation and rotation therewith, the swivel and valve being substantially shielded from waterjet back-splash;   structure supporting the cutting head and rotating with said cutting head about said other axis of rotation; and   a drive mechanism for rotating the cutting head about said one axis of rotation, said drive mechanism being substantially housed within said supporting and rotating structure.   
     
     
         2 . The cutting system of  claim 1  wherein said one axis of rotation is the A-axis, and said other axis of rotation is the C-axis associated with the waterjet cutting system. 
     
     
         3 . A waterjet cutting system comprising:
 a cutting head for producing a waterjet and directing the waterjet at a workpiece;   a C-axis structure for supporting and rotating the cutting head about the C-axis;   a hi-pressure water-conducting swivel and a valve serially coupled in fluidic communication to conduct high pressure water from an exterior source to the cutting head, said swivel and valve being mounted adjacent to the cutting head for rotation therewith about at least one axis of rotation other than the C-axis;   a shielding structure mounted for rotation with the cutting head and positioned to shield the swivel and valve from waterjet back-splash ; and   a drive mechanism for controllably rotating the cutting head about said other axis of rotation, said drive mechanism being supported substantially within the C-axis structure in such a way as to refrain from interfering with the clearance between the cutting head and workpiece while being substantially shielded from waterjet back-splash,   said C-axis structure including an internal fluid path for conducting high pressure water from an external source to said serially coupled water-conducting swivel and valve.   
     
     
         4 . The cutting system of  claim 3  wherein the internal fluid path of the C-axis structure has upstream and downstream ends, and further including
 a second swivel in fluid communication with the upstream end of the internal fluid path to couple the internal fluid path to the external high pressure water source while permitting the C-axis structure to rotate about the C-axis. 
 
     
     
         5 . The waterjet cutting system of  claim 3  wherein the shielding structure forms a portion of the cutting head housing. 
     
     
         6 . The waterjet cutting system of  claim 3  wherein the shielding structure is a housing coupled to the cutting head for rotation therewith and substantially enclosing the swivel and on/off valve. 
     
     
         7 . The cutting system of  claim 3  wherein said one axis of rotation is selected from the A-axis and the B-axis. 
     
     
         8 . The cutting system of  claim 3  including an actuator  30  operative on the valve responsive to a control signal to selectively block and permit fluid flow through the valve to deactivate and activate production of the waterjet. 
     
     
         9 . A waterjet cutting system comprising:
 cutting head having a housing that has a high pressure water inlet, a jet-forming orifice-defining member, an internal fluid path for conducting high pressure water from the inlet to the orifice-defining member and a discharge fluid path for discharging the waterjet from the cutting head, said cutting head being configured to accept a cutting nozzle within its discharge path to direct the discharged jet against a workpiece;   a cutting head inlet swivel mounted to the cutting head at its water inlet to conduct high-pressure water into the cutting head's internal fluid path;   a carriage for controllably adjusting the height of the cutting head in response to a control signal when the cutting head is mounted to the carriage, said adjustment being along a Z-axis of translation;   a C-axis member mounted on the carriage for supporting the cutting head, the C-axis member being rotatable about a C-axis of rotation that is parallel to the Z axis, the cutting head being supported by the C-axis member for rotation therewith,   the C-axis member having an upstream fluid inlet, a relatively downstream fluid outlet, and an internal passageway therebetween for permitting the flow of high-pressure water from the inlet and through the outlet via the internal passageway,   a C-axis swivel within the upstream fluid inlet of the C-axis structure for conducting high-pressure water from an external source to the C-axis member's internal passageway   a swivel/valve combination including a high-pressure water-conducting swivel in serially disposed fluidic communication with an on/off valve mounted on the C-axis structure and mechanically coupling the cutting head to the C-axis structure, the swivel/valve combination being mounted to the C-axis structure for rotation about an axis that is perpendicular to the C-axis, whereby the swivel/valve combination and cutting head can rotate about the C-axis and said perpendicular axis in response to respective control signals,   a conduit for conducting the high-pressure water passing through the C-axis member into the swivel of the swivel/valve combination, the valve of said combination having an outlet fluidically coupled to the inlet of said cutting head and configured to selectively block the flow of high pressure water from the C-axis structure from entering the cutting head;   a drive mechanism for rotating the swivel/valve combination and the coupled cutting head about said perpendicular axis,   said C-axis structure having an internal cavity for substantially housing the drive mechanism.   
     
     
         10 . The cutting system of  claim 9  wherein the internal cavity of the C-axis member is adjacent the valve/swivel combination. 
     
     
         11 . The cutting system of  claim 9  including a protective housing substantially enclosing the valve/swivel combination. 
     
     
         12 . The cutting system of  claim 11  wherein the protective housing is spaced from the cutting head. 
     
     
         13 . The cutting system of  claim 9  wherein the valve of the swivel/valve combination is a needle valve. 
     
     
         14 . The cutting system of  claim 9  wherein the C-axis swivel is axially aligned with the C-axis. 
     
     
         15 . The cutting system of  claim 9  wherein the drive mechanism includes
 an electric stepping motor, 
 
       a pair of tie rods driven by the motor and coupled the cutting head to rotate the cutting head about said perpendicular axis to a desired angular position. 
     
     
         16 . The cutting system of  claim 9  wherein the drive mechanism includes
 an electric stepping motor, 
 a helically-threaded shaft controllably rotated by the stepping motor, and 
 a coupling block that engages the threaded shaft to move linearly in a path generally parallel to the C-axis, and 
 a set of linkages coupled to the coupling block and to the cutting head to cause rotation of the cutting head about said perpendicular axis in response to said linear movement of the coupling block. 
 
     
     
         17 . The cutting system of  claim 9  wherein the drive mechanism includes an electric stepping motor and a belt and pulley system for rotating the cutting head about said perpendicular axis,
 the belt and pulley system including a split belt, an idler pulley, a driven pulley first and second coupling blocks, a carriage and a threaded shaft, 
 the driven pulley having an axis of rotation generally aligned with said perpendicular axis and coupled to the cutting head to rotate the coupling head about said perpendicular axis when rotated, 
 the split belt being coupled at one end to the first coupling block and extending therefrom around the idler pulley, and then towards and around the driven pulley to the second coupling block, to which the belt's other end is affixed, 
 said coupling block being mounted on or integral with the carriage, 
 the carriage engaging the threaded shaft, 
 the threaded shaft being controllably rotated by the stepping motor to move the carriage generally linearly in a path generally parallel to the C-axis to thereby cause rotation of the driven pulley and cutting head about said perpendicular axis via the belt. 
 
     
     
         18 . The cutting system of  claim 17  including
 a protective housing spaced from the cutting head and substantially enclosing the valve/swivel combination, said protective housing having a support arm extending generally parallel to said perpendicular axis, 
 the driven pulley being mounted generally about said arm of the protective housing to rotate the housing and cutting head about said perpendicular axis.