Welder with positional heat control and method of using same

Abstract

An electric arc welder for producing a weave pattern across a workpiece with a succession of individual weld short runs or bead, each of which has a center portion extending between two transversely spaced edges. The welder comprising a power source, a wire feeder to direct a welding wire through a movable torch to the workpiece and a controller for creating a welding current between the wire and the workpiece. A mechanical device is used to move the torch along the bead and the controller has a program to perform a first weld process while the torch is moving along the center portion and a second weld process when the torch is adjacent the edges, where the first weld process has less heat input than the second weld process.

1 . An electric arc welder for producing a weave pattern across a workpiece with a succession of individual weld runs each of which has a center portion extending between two transversely spaced edges, the welder comprising:
 a power source;   a wire feeder; and   a controller for causing the power source to perform a first weld process in the center portion and a second weld process adjacent at least one of the edges.   
   
   
       2 . An electric arc welder as defined in  claim 1  wherein the controller performs the second weld process adjacent both of the edges. 
   
   
       3 . An electric arc welder as defined in  claim 1  wherein the controller performs a third weld process adjacent another of the edges. 
   
   
       4 . An electric arc welder as defined in  claim 2  wherein the first weld process is a lower heat process than the second weld process. 
   
   
       5 . An electric arc welder as defined in  claim 4  wherein the first process is selected from the class consisting of short arc transfer GMAW, surface tension transfer, low power mode, low WFS, negative polarity shorting transfer, low duty cycle VP-GMAW and CMT transfer. 
   
   
       6 . An electric arc welder as defined in  claim 4  wherein the second process is selected from the class consisting of spray transfer GMAW, pulsed spray transfer, high power mode, high WFS, positive polarity pulse and high duty cycle VP-GMAW. 
   
   
       7 . An electric arc welder as defined in  claim 1  wherein the controller includes software to create a flag wherein the welder is to transition from one of the weld processes to the other of the weld processes upon creation of the program flag. 
   
   
       8 . An electric arc welder as defined in  claim 7  wherein software of the controller creates the flag based upon a timer, a counter, a position switch, a sensed arc voltage, arc current and/or power, or combinations thereof. 
   
   
       9 . An electric arc welder as defined in  claim 1  wherein the first process includes control of the power source and control of the wire feed speed of the wire feeder of the welder. 
   
   
       10 . An electric arc welder as defined in  claim 1  wherein the second process includes control of the power source and control of the wire feed speed of the wire feeder of the welder. 
   
   
       11 . An electric arc welder as defined in  claim 1  wherein the power source is an inverter operated by a pulse width modulator with a control input for creating high frequency pulses with a width or duty cycle to control output current and/or voltage of the power source based upon the signal on the control input. 
   
   
       12 . An electric arc welder as defined in  claim 11  including a system having a waveform generator with an output and a digital circuit for comparing the output with the arc current or voltage of the power source to create a waveform profile signal driving the control input of the pulse width modulator. 
   
   
       13 . An electric arc welder as defined in  claim 1  wherein the workpiece is an open root between spaced plates and the center portion spans the open root and the edges are on the plates. 
   
   
       14 . An electric arc welder as defined in  claim 1  wherein the first weld process is a surface tension transfer process. 
   
   
       15 . An electric arc welder as defined in  claim 1  wherein the second weld process is a spray or pulse transfer process. 
   
   
       16 . An electric arc welder as defined in  claim 1  wherein the first weld process is electrode negative. 
   
   
       17 . An electric arc welder as defined in  claim 1  wherein the second weld process is electrode positive. 
   
   
       18 . An electric arc welder for producing a weave pattern across a workpiece with a succession of individual weld runs, each of which has a center portion extending between two transversely spaced edges, the welder comprising:
 a power source;   a wire feeder to direct a welding wire through a movable torch to the workpiece;   a controller for creating a welding current between the wire and the workpiece; and   a mechanical device for moving the torch along the weave pattern;   wherein the controller has a program to perform a first weld process while the torch is moving along the center portion and a second weld process when the torch is adjacent the edges; and   wherein the first weld process has less heat input than the second weld process.   
   
   
       19 . A method of producing a weave pattern across a workpiece with a succession of individual weld runs, each of which has a center portion extending between two transversely spaced edges, the method comprising:
 (a) creating a welding current between a workpiece and a welding wire moving through a torch toward the workpiece;   (b) moving the torch along the weave pattern;   (c) performing a first weld process while the torch is moving along the center portion;   (d) performing a second weld process when the torch is adjacent the edges; and,   (e) causing the first weld process to have less heat input than the second weld process.   
   
   
       20 . A method as defined in  claim 19  including:
 (f) holding the controller at the first weld process by a control element as the torch moves from a first position adjacent a first of the edges and until the torch reaches a second position adjacent the second of the edges.   
   
   
       21 . A method as defined in  claim 19  including:
 (g) providing a position identifying switch adjacent each of the edges and the welder; and,   (h) reversing the direction of the torch at each of the switches.   
   
   
       22 . A method as defined in  claim 19  wherein the first process is selected from the class consisting of short arc transfer GMAW, surface tension transfer, low power mode, low WFS, negative polarity shorting transfer, low duty cycle VP-GMAW and CMT transfer. 
   
   
       23 . A method as defined in  claim 19  wherein the second process is selected from the class consisting of spray transfer GMAW, pulsed spray transfer, high power mode, high WFS, positive polarity pulse and high duty cycle VP-GMAW.