Method of using image data in the production of thin wall extrusions

Abstract

A method of coating metal wire with extrudate using an extrusion system. The method includes the steps of advancing the metal wire through an extrusion die of the extrusion system and extruding molten extrudate over the metal wire as the metal wire is advanced through the extrusion die. Image data is generated, using one or several electronic cameras, concurrently with the advancing, and extruding to provide visual feedback indicative of the concentricity or non-concentricity of extrudate surrounding the metal wire as the metal wire exits the extrusion die.

1 . A process for producing an ultra-thin walled, pinhole free thermoplastic polymer coated conductor, comprising:
 (a) providing an extruder for producing polymer coated wires, including (i) a die, comprising an opening out of which a wire is pulled, surrounded by molten extrudate; and (ii) a heater set immediately outside of the opening;   (b) introducing molten thermoplastic material into the die;   (c) filtering the molten thermoplastic material to remove thermally degraded polymer material greater than  3  microns in diameter;   (d) pulling wire through the die as the molten thermoplastic material is being introduced into the die, thereby forming an extrudate swell about the wire as it exits the die; and   (e) while the wire is being pulled through the die, controlling the heater to raise the temperature in the immediate vicinity of the opening, thereby subjecting the extrudate swell to a heat that allows for a finished extrudate having a wall thickness of less than about 50.8 microns (2 mils) to be produced without shear or pinholes.   
     
     
         2 . The process of  claim 1  wherein the wire has a diameter of about 25.4 microns (1 mil). 
     
     
         3 . The process of  claim 1  further comprising:
 operating a feedback loop using a temperature measurement sensor to control the heater. 
 
     
     
         4 . The process of  claim 1  further comprising:
 visually inspecting the concentricity of the finished extrudate. 
 
     
     
         5 . The process of  claim 4  further comprising:
 adjusting positioning of the die of the extruder during operation of the extruder in response to the visually inspecting. 
 
     
     
         6 . The process of  claim 5  wherein the adjusting occurs using die adjusting screws. 
     
     
         7 . The process of  claim 5  wherein the adjusting occurs using piezoelectric actuators.