Ultrasonic disruption of an anodotic film during electropolishing of medical implants

Abstract

A method of electropolishing a medical implant is provided. During the electropolishing, an anodotic film forms around surfaces of the implant. Two or more ultrasonic transducers are oriented around the implant and are activated to disrupt the anodotic film. The ultrasonic transducers are activated only during a portion of the electropolishing process to allow the anodotic film to at least partially reform.

I claim: 
     
         1 . A method of electropolishing a medical implant, comprising:
 immersing said medical implant, an anode and a cathode in an electrolytic fluid;   contacting a surface of said implant with said anode;   applying a voltage across said anode and said cathode, said implant thereby being electropolished and an anodotic film forming on a surface of said medical implant;   activating a first ultrasonic transducer, said first ultrasonic transducer introducing a first wave through said electrolytic fluid and disrupting at least a portion of said anodotic film;   activating a second ultrasonic transducer, said second ultrasonic transducer introducing a second wave through said electrolytic fluid and disrupting at least a portion of said anodotic film, said first and second ultrasonic transducers being disposed at least about 45° apart from each other; and   applying a voltage across said anode and said cathode after activating said first and second ultrasonic transducers, said implant thereby being electropolished after said anodotic film is disrupted.   
     
     
         2 . The method according to  claim 1 , wherein said voltage is applied across said anode and said cathode before said first and second ultrasonic transducers are activated. 
     
     
         3 . The method according to  claim 1 , wherein said cathode is disposed along a wall defining a bath of said electrolytic fluid. 
     
     
         4 . The method according to  claim 1 , wherein said cathode is disposed along an entirety of said wall defining said bath. 
     
     
         5 . The method according to  claim 1 , wherein said first and second ultrasonic transducers are disposed at least about 90° apart from each other. 
     
     
         6 . The method according to  claim 5 , wherein said first and second ultrasonic transducers are disposed more than 90° apart from each other. 
     
     
         7 . The method according to  claim 1 , further comprising activating a third ultrasonic transducer, said third ultrasonic transducer introducing a third wave through said electrolytic fluid and disrupting at least a portion of said anodotic film, and activating a fourth ultrasonic transducer, said fourth ultrasonic transducer introducing a fourth wave through said electrolytic fluid and disrupting at least a portion of said anodotic film, said first, second, third and fourth ultrasonic transducers being disposed at least about 90° apart from each other. 
     
     
         8 . The method according to  claim 7 , wherein said first, second, third and fourth ultrasonic transducers are activated sequentially, said second ultrasonic transducer being disposed at least about 120° apart from said first ultrasonic transducer, said third ultrasonic transducer being disposed at least about 90° apart from said second ultrasonic transducer, and said fourth ultrasonic transducer being disposed at least about 120° apart from said third ultrasonic transducer. 
     
     
         9 . The method according to  claim 1 , wherein said first and second ultrasonic transducers are activated at different times. 
     
     
         10 . The method according to  claim 9 , wherein said first and second ultrasonic transducers are each activated for about 2 to about 60 seconds. 
     
     
         11 . The method according to  claim 10 , wherein said first and second ultrasonic transducers are each activated for about 2 to about 15 seconds. 
     
     
         12 . The method according to  claim 11 , wherein said first and second ultrasonic transducers are each activated for about 2 to about 5 seconds. 
     
     
         13 . The method according to  claim 9 , wherein said first and second ultrasonic transducers are activated sequentially. 
     
     
         14 . The method according to  claim 13 , wherein said voltage is applied across said anode and said cathode while said first and second ultrasonic transducers are activated, said implant thereby being electropolished while said anodotic film is disrupted by said first and second ultrasonic transducers. 
     
     
         15 . The method according to  claim 13 , further comprising pausing said first and second ultrasonic transducers between activating said first and second ultrasonic transducers. 
     
     
         16 . The method according to  claim 15 , wherein said voltage is applied across said anode and said cathode while said first and second ultrasonic transducers are paused, said implant thereby being electropolished and said anodotic film forming during said pause. 
     
     
         17 . The method according to  claim 16 , wherein said pause is about 1 to about 10 seconds. 
     
     
         18 . The method according to  claim 16 , wherein said pause is about 3 to about 5 seconds. 
     
     
         19 . The method according to  claim 1 , wherein said first and second ultrasonic transducers are disposed at least about 90° apart from each other, said first and second ultrasonic transducers are activated at different times, said first and second ultrasonic transducers are activated sequentially, and said voltage is applied across said anode and said cathode while said first and second ultrasonic transducers are activated, said implant thereby being electropolished while said anodotic film is disrupted by said first and second ultrasonic transducers. 
     
     
         20 . The method according to  claim 19 , further comprising pausing said first and second ultrasonic transducers between activating said first and second ultrasonic transducers, said voltage is applied across said anode and said cathode while said first and second ultrasonic transducers are paused, said implant thereby being electropolished and said anodotic film forming during said pause, said first and second ultrasonic transducers are each activated for about 2 to about 15 seconds, and said pause is about 1 to about 10 seconds. 
     
     
         21 . The method according to  claim 20 , wherein said first and second ultrasonic transducers are each activated for about 2 to about 5 seconds, and said pause is about 3 to about 5 seconds. 
     
     
         22 . The method according to  claim 21 , further comprising activating a third ultrasonic transducer, said third ultrasonic transducer introducing a third wave through said electrolytic fluid and disrupting at least a portion of said anodotic film, activating a fourth ultrasonic transducer, said fourth ultrasonic transducer introducing a fourth wave through said electrolytic fluid and disrupting at least a portion of said anodotic film, and pausing said second and third ultrasonic transducers between activating said second and third ultrasonic transducers, pausing said third and fourth ultrasonic transducers between activating said third and fourth ultrasonic transducers, said voltage is applied across said anode and said cathode while said first, second, third and fourth ultrasonic transducers are paused, said implant thereby being electropolished and said anodotic film forming during said pauses, said first, second, third and fourth ultrasonic transducers are each activated for about 2 to about 5 seconds, and said pauses are about 3 to about 5 seconds, and said first, second, third and fourth ultrasonic transducers are activated sequentially, said second ultrasonic transducer being disposed at least about 120° apart from said first ultrasonic transducer, said third ultrasonic transducer being disposed at least about 90° apart from said second ultrasonic transducer, and said fourth ultrasonic transducer being disposed at least about 120° apart from said third ultrasonic transducer. 
     
     
         23 . The method according to  claim 21 , wherein said cathode is disposed along a wall defining a bath of said electrolytic fluid, and said voltage is applied across said anode and said cathode before said first, second, third and fourth ultrasonic transducers are activated.