Automatic airfoil root prep machine and associated method

Abstract

An apparatus for polishing an airfoil root includes a fixture for holding the airfoil, an actuation cylinder assembly for moving the fixture holding the airfoil, a brush, a motor for rotating the brush, a switch, and control circuitry. The actuation cylinder assembly is configured to move the fixture holding the airfoil toward the brush to trigger the switch, and the control circuitry is configured to run a timer when the switch is triggered to control contact between the airfoil and the brush for polishing.

The invention claimed is:  
     
       1. An apparatus for polishing an airfoil root, the apparatus comprising:
 a fixture for holding the airfoil;  
 an actuation cylinder assembly for moving the fixture holding the airfoil;  
 a brush;  
 a motor for rotating the brush;  
 a switch, wherein the actuation cylinder assembly is configured to move the fixture holding the airfoil toward the brush to trigger the switch; and  
 control circuitry, wherein the control circuitry is configured to run a timer when the switch is triggered to control contact between the airfoil and the brush for polishing.  
 
     
     
       2. The apparatus of  claim 1 , wherein the actuation cylinder assembly comprises a linear pneumatic cylinder. 
     
     
       3. The apparatus of  claim 1  and further comprising:
 a limit switch configured to detect excessive travel of the fixture indicative of brush wear or the absence of the airfoil in the fixture.  
 
     
     
       4. The apparatus of  claim 1  and further comprising:
 a hood for shielding at least the brush during operation.  
 
     
     
       5. The apparatus of  claim 4  and further comprising:
 a proximity sensor for detecting whether the hood is open.  
 
     
     
       6. The apparatus of  claim 1  and further comprising:
 a pair of operator controls for activating the apparatus to perform a polishing operation, wherein the pair of operator controls are configured such that all must be triggered to activate the apparatus to perform a polishing operation.  
 
     
     
       7. The apparatus of  claim 1 , wherein the actuation cylinder is pressurized at approximately 96.53 kPa (14 psi) to advance the fixture. 
     
     
       8. The apparatus of  claim 1 , wherein timer is configured to run to a time period of approximately 1-2 seconds before the actuation cylinder moves the fixture away from the brush, wherein the actuation cylinder continues to advance the fixture toward the brush during the time period of the timer. 
     
     
       9. The apparatus of  claim 1  and further comprising:
 a vent system for venting airborne material present during operation of the apparatus.  
 
     
     
       10. The apparatus of  claim 1  and further comprising:
 a mask for masking a portion of the airfoil during polishing.  
 
     
     
       11. A method of polishing a workpiece, the method comprising:
 positioning the workpiece in a fixture, wherein the fixture is movable;  
 rotating a brush;  
 moving the fixture toward the rotating brush at a given pressure in the actuation cylinder so that the workpiece can contact the brush;  
 triggering timer when a position of the fixture reaches a given point relative to the rotating brush; and  
 moving the fixture away from the rotating brush with the actuation cylinder after a time period of the timer has elapsed.  
 
     
     
       12. The method of  claim 11 , wherein time period of the timer is approximately 1-2 seconds. 
     
     
       13. The method of  claim 11 , wherein operation of the actuation cylinder continues to advance the fixture toward the brush during the time period of the timer. 
     
     
       14. The method of  claim 13 , wherein a pressure in the actuation cylinder to move the fixture toward the rotating brush is approximately 96.53 kPa (14 psi). 
     
     
       15. The method of  claim 11 , wherein the brush is rotated for at least 2 minutes when activated to reduce motor cycling between polishing operations. 
     
     
       16. The method of  claim 11  and further comprising:
 detecting a movement limit of the fixture relative to the rotating brush, to detect excessive movement of the fixture.