Electrode coating apparatus and method

Abstract

A method and apparatus for the processing of surface coating is disclosed concerning the design of an ultrasonic pressurized rotating friction head assembly used to apply a surface coating to a workpiece. The shape of the friction head may be flat or curved as appropriate for the workpiece. The surface coating is rotated under repetaed contact and ultrasonic vibration. The apparatus includes: a work station for the mounting and rotation of a TiC coated welding electrode workpiece; a rotating friction head assembly with an ultrasonic transducer and power source. Concurrent application of pressurized rotating friction and ultrasonic vibration, may tend to reduce the defects in the TiC coatings on welding electrodes produced using the electro-spark deposition process. While maintaining the basic coating material component contents, mechanical and physical properties unaltered, defects such as delaminations, cracks, discontinuities and voids may be reduced. Control and operation of the may be adapted to other applications.

We claim: 
     
         1 . A process of surface treatment of an ESD coating, said process comprising:
 biasing a friction head assembly against a workpiece to which an ESD coating is applied;   moving the workpiece relative to the friction head while in contact therewith; and   subjecting the coating to ultrasonic vibration while the friction head is in contact therewith.   
     
     
         2 . The process of  claim 1  wherein said process includes rotating said workpiece while said friction head is in contact therewith. 
     
     
         3 . The process of  claim 1  wherein said process includes rotating said friction head assembly while it is in contact with the workpiece. 
     
     
         4 . The process of  claim 3  wherein said process includes rotating said workpiece while said friction head is in contact therewith. 
     
     
         5 . The process of  claim 1  wherein said coating is a TiC coating. 
     
     
         6 . The process of  claim 1  wherein said process includes depositing said ESD coating. 
     
     
         7 . The process of  claim 1  wherein at least one of:
 (a) there is an ultrasonic frquency of about 50 kHz; 
 (b) there is a biasing force of about 200 N; and 
 (c) there is a rotational speed of the rotating friction head of about 1400 rpm. 
 
     
     
         8 . An apparatus for the processing of surface coating modifications of an ESD coating on a workpiece surface, wherein said apparatus comprises:
 a work station for the mounting and rotation of the workpiece;   a friction assembly, operable, in use, to be biased against the workpiece; and   an ultrasonic transducer mounted to transmit ultrasonic vibration to the workpiece while the workpiece is in contact with the rotating friction assembly.   
     
     
         9 . The apparatus of  claim 8  wherein said apparatus comprises an ultrasonic power source; the ultrasonic transducer being connected to the ultrasonic power source. 
     
     
         10 . The apparatus of  claim 8  wherein said friction head has a shape that is one of (a) flat; and
 (b) curved. 
 
     
     
         11 . The apparatus of  claim 8  wherein said friction assembly is also mounted for rotation. 
     
     
         12 . The apparatus of  claim 8  wherein at least one of:
 (a) the ultrasonic transducer operates at about 50 kHz; 
 (b) in use, the biasing force is about 200 N; and 
 (c) the friction head is mounted for rotation at about 1400 rpm.