Coating Apparatus and Methods

Abstract

A coating end effector may be carried by a robot. A plasma spray head is mounted by a joint to the end effector. A plurality of actuators couple the end effector and plasma spray head to provide articulation of the joint. The apparatus may be used to coat an airfoil cluster of a gas turbine engine. The coating may include passing the head between the airfoils.

1 . A method comprising:
 coating an airfoil cluster, the airfoil cluster comprising a metallic substrate including:
 at least first and second airfoils, each airfoil having a pressure side and a suction side, the pressure side of the first airfoil facing the suction side of the second airfoil, 
   
       wherein the coating comprises:
 moving a robotic end effector carrying a plasma spray head; 
 articulating a joint between the end effector and plasma spray head; and 
 discharging a plasma spray from the plasma spray head to coat the cluster, including while the plasma spray head is between the first and second airfoils. 
 
     
     
         2 . The method of  claim 1  wherein:
 the cluster is a vane cluster having:
 a platform; 
 a shroud; and 
 at least said first and second airfoils extending between an outer face of the platform and an inner face of the shroud; and 
 
 the articulating moves the plasma spray head between the platform and shroud. 
 
     
     
         3 . The method of  claim 2  wherein:
 the articulating comprises combined pitch, roll, and yaw. 
 
     
     
         4 . The method of  claim 1  wherein:
 the articulating comprises a pitch articulation. 
 
     
     
         5 . The method of  claim 1  wherein:
 the articulating comprises a combined at least two of pitch, roll, and yaw. 
 
     
     
         6 . The method of  claim 1  further comprising:
 separately directing flows of a carrier gas and a powder coating material to the plasma spray head. 
 
     
     
         7 . The method of  claim 1  further comprising:
 installing the end effector to a six-axis robot. 
 
     
     
         8 . A coating apparatus comprising:
 a robot;   an end effector carried by the robot;   a plasma spray head;   a joint mounting the plasma spray head to the end effector; and   a plurality of actuators coupling the end effector and plasma spray head to provide multi-axis articulation of the joint.   
     
     
         9 . The apparatus of  claim 8  wherein:
 the articulation is multi-axis articulation. 
 
     
     
         10 . The apparatus of  claim 8  wherein:
 the articulation includes pitch articulation. 
 
     
     
         11 . The apparatus of  claim 8  wherein:
 the joint is a ball and socket joint. 
 
     
     
         12 . The apparatus of  claim 8  wherein:
 the there are exactly three said actuators. 
 
     
     
         13 . The apparatus of  claim 8  wherein:
 the actuators are push-pull actuators. 
 
     
     
         14 . The apparatus of  claim 8  wherein:
 at least one of the actuators comprises a flexible member passing through a guide on the end effector. 
 
     
     
         15 . The apparatus of  claim 8  further comprising:
 a flexible conduit coupled to the plasma spray head to guide a carrier gas and powder flow to the plasma spray head; 
 a flexible conduit coupled to the head to guide a plasma gas flow to the plasma spray head; 
 a flexible conduit coupled to the head to guide a coolant flow to the plasma spray head; 
 a flexible conduit coupled to the head to guide the coolant flow from the plasma spray head; and 
 at least one electrical power line coupled to the plasma spray head. 
 
     
     
         16 . The apparatus of  claim 8  further comprising:
 a controller programmed to operate and articulate the plasma spray head to apply a coating to a vane cluster. 
 
     
     
         17 . The apparatus of  claim 16  wherein:
 the controller is programmed to operate and articulate the plasma spray head to so that the plasma spray head passes between first and second airfoils of the cluster. 
 
     
     
         18 . A coating apparatus comprising:
 a plasma spray head;   an end effector;   a joint mounting the plasma spray head to the end effector; and   a plurality of push-pull actuators coupling the end effector and plasma spray head to provide multi-axis articulation of the joint.   
     
     
         19 . The apparatus of  claim 18  wherein:
 the actuators are positioned to provide three-axis articulation of the joint. 
 
     
     
         20 . The apparatus of  claim 18  further comprising:
 a controller programmed to operate and articulate the joint to coat a vane cluster wherein the plasma spray head passes between first and second airfoils of the vane cluster.