Compensation for a fluid cutting apparatus

Abstract

A system and method for positioning a fluid stream for cutting a double contour workpiece includes a compensation module configured to receive information regarding a contour path in at least five degrees of freedom for cutting the double contour workpiece and a velocity of movement of the fluid stream during cutting and configured to provide as an output a modified contour path of said at least five degrees of freedom based on Kerf compensation errors. A motion controller is adapted to receive the modified contour path of said at least five degrees of freedom and the velocity and is configured to provide control signals. A positioner is configured to receive the control signals and position a fluid stream adjacent the workpiece accordingly.

1 . A system for positioning a fluid stream for cutting a double contour workpiece, the system comprising: 
 a compensation module configured to receive information regarding a contour path in at least five degrees of freedom for cutting the double contour workpiece and a velocity of movement of the fluid stream during cutting and configured to provide as an output a modified contour path of said at least five degrees of freedom based on Kerf compensation errors;    a motion controller adapted to receive the modified contour path of said at least five degrees of freedom and the velocity and configured to provide control signals; and    a positioner configured to receive the control signals and position a fluid stream adjacent the workpiece accordingly.    
     
     
         2 . The system of  claim 1  wherein the motion controller is adapted to provide information related to changes in velocity of the fluid stream during cutting across the workpiece, and wherein the compensation module is adapted to modify the contour path based on the change in the velocity.  
     
     
         3 . The system of  claim 1  and further comprising means for indicating a change in thickness of the double contour workpiece at the point of cutting, and wherein the compensation module is adapted to modify the contour path based on a change in thickness.  
     
     
         4 . The system of  claim 3  wherein the means for indicating a change in thickness of the double contour workpiece at the point of cutting includes a sensor adapted to measure the thickness at the point of cutting.  
     
     
         5 . The system of  claim 3  wherein the means for indicating a change in thickness of the double contour workpiece at the point of cutting includes positional information pertaining to the design of the workpiece.  
     
     
         6 . The system of  claim 1  wherein the compensation module includes a compensation assembly that is adapted to receive information regarding a contour path in at least five degrees of freedom for cutting the double contour workpiece and the velocity of movement of the fluid stream during cutting and that is adapted to provide information related to Kerf compensation based on empirical data.  
     
     
         7 . The system of  claim 6  wherein the empirical data is of the form of polynomial equations.  
     
     
         8 . The system of  claim 6  wherein the compensation module includes a Kerf compensation component configured to receive the information related to Kerf compensation based on empirical data, the contour path and the velocity and provide the modified contour path of said at least five degrees of freedom.  
     
     
         9 . The system of  claim 8  wherein the Kerf compensation component includes a module configured to determine a tool path vector at any point along the contour path, and wherein the modified contour path of said at least five degrees of freedom is based on the tool path vector.  
     
     
         10 . The system of  claim 9  wherein the Kerf compensation component includes: 
 a first module configured to determine Kerf compensation errors in at least 5 dimensions based on the tool path vector are in a coordinate system different that the contour path; and    a second module configured to use the Kerf compensation errors in at least 5 dimensions based on the tool path vector in the coordinate system different that the contour path to provide the modified contour path.    
     
     
         11 . The system of  claim 9  wherein the motion controller is adapted to provide information related to changes in velocity during cutting, and wherein the compensation module is adapted to modify the contour path based on the change in velocity.  
     
     
         12 . The system of  claim 9  and further comprising means for indicating a change in thickness of the double contour workpiece at the point of cutting, and wherein the compensation module is adapted to modify the contour path based on a change in thickness.  
     
     
         13 . The system of  claim 12  wherein the means for indicating a change in thickness of the double contour workpiece at the point of cutting includes a sensor adapted to measure the thickness at the point of cutting, and wherein the compensation assembly is adapted to modify the Kerf information based on change in thickness.  
     
     
         14 . The system of  claim 12  wherein the means for indicating a change in thickness of the double contour workpiece at the point of cutting includes positional information pertaining to the design of the workpiece, and wherein the compensation assembly is adapted to modify the Kerf information based on thickness from positional information pertaining to the design of the workpiece.  
     
     
         15 . A method for providing a contour path for cutting a double contour workpiece, the method comprising: 
 receiving information regarding a contour path in at least five degrees of freedom for cutting the double contour workpiece and a velocity of movement of the fluid stream during cutting;    determining a modified contour path of said at least five degrees of freedom based on Kerf compensation errors; and    outputting the modified contour path.    
     
     
         16 . The method of  claim 15  and further comprising receiving information related to changes in velocity of the fluid stream during cutting across the workpiece, and wherein determining the modified contour path of said at least five degrees of freedom based on Kerf compensation errors includes being based on the change in the velocity.  
     
     
         17 . The method of  claim 15  and further comprising receiving information related to changes in a thickness of the double contour workpiece at the point of cutting, and wherein determining the modified contour path of said at least five degrees of freedom based on Kerf compensation errors includes being based on a change in thickness.