Method and Apparatus for Controlling a Welding System

Abstract

A method and apparatus for controlling a welding-type power supply includes providing a current wave form having an arc current portion and a short circuit current portion. An arc state is entered by retracting a welding wire, and a short circuit state is entered by advancing the wire. The current enters the arc current portion prior to the creation of the arc and the current enters the short circuit current portion prior to the creation of the short, by coordinating the wave form with the wire retraction. This may be preformed on a wire having a diameter of 2.4 mm or more to a weld and applying a welding current of less than 100 amps, or of less than 35 amps. One current waveform during the arc state includes at least three segments, and the last segment is entered into prior to the short circuit state being entered, and is the same current magnitude as the current magnitude at the start of the short circuit state. Penetration and/or bead formation may be controlled by controlling the advancement of the wire into the weld pool. The balance may be user set.

1 . A method of controlling a welding-type power supply comprising:
 providing a current wave form having an arc current portion and a short circuit current portion;   causing an arc state to be entered by retracting a welding wire;   causing a short circuit state to be entered by advancing the wire;   causing the current to enter the arc current portion prior to the creation of the arc by coordinating the wave form with the wire retraction;   causing the current to enter the short circuit current portion prior to the creation of the short by coordinating the wave form with the wire advancing.   
   
   
       2 . The method of  claim 1 , further comprising controlling the penetration by controlling the advancement of the wire into the weld pool. 
   
   
       3 . The method of  claim 1 , further comprising controlling bead formation by controlling the advancement of the wire into the weld pool. 
   
   
       4 . The method of  claim 1 , wherein the current magnitude during the arc portion and the short portion is used to control heat applied to the weld, and wherein advancing and retracting the wire is used to control the time at which the process transitions from the arc state to the short circuit state and from the short circuit state to the arc state. 
   
   
       5 . The method of  claim 1 , further comprising determining a time T 1  for the transition between the arc state and the short circuit state, and retracting the wire such that the arc is created by time T 1 , and determining a time T 2  for a transition from the arc state to the short circuit state, and retracting the wire such that the short circuit state is entered by the time T 2 . 
   
   
       6 . The method of  claim 5 , further comprising changing the current wave form from the short circuit portion to the arc portion by the time T 1 , and the changing the wave form from the arc portion to the short circuit portion by the time T 2 . 
   
   
       7 . The method of  claim 1 , further comprising, controlling the portion of time the process spends in the arc state relative to the short circuit state, by controlling the length of time between the successive retraction and advancing of the wire. 
   
   
       8 . The method of  claim 7 , further comprising receiving a user selectable input indicative of a desired arc state time relative to short circuit state time. 
   
   
       9 . The method of  claim 1 , further comprising controlling the welding process to enter a pulse state, in addition to the arc state and the short circuit state, wherein the amount of time spend in the pulse state, relative to the short circuit state, is responsive to a user selectable input. 
   
   
       10 . The method of  claim 9 , further comprising, controlling the mixture of gas from two or more sources in response to the users selectable input. 
   
   
       11 . The method of  claim 1 , further comprising controlling the welding process to enter a pulse state, in addition to the arc state and the arc state, wherein the amount of time spend in the pulse state, relative to the arc state, is responsive to a user selectable input. 
   
   
       12 . The method of  claim 11 , further comprising, controlling the mixture of gas from two or more sources in response to the users selectable input. 
   
   
       13 . The method of  claim 1 , further comprising controlling the penetration by controlling the polarity of the current, wherein the polarity is changed a plurality of times to control the penetration. 
   
   
       14 - 66 . (canceled) 
   
   
       67 . A welding-type power supply for short circuit welding comprising:
 means feeding wire to a weld; disposed near the wire;   means for advancing the wire to enter into a short circuit state, disposed near the wire;   means for retracting the wire while the wire is advancing to a torch, disposed near the wire, thereby entering an arc state; and   means for using polarity control to control the heat applied to the weld pool, connected to a power source, disposed to provide power to the wire.   
   
   
       68 - 71 . (canceled) 
   
   
       72 . A welding-type power supply for short circuit welding comprising:
 means for feeding and retracting a wire, disposed to drive wire to a weld;   means for providing welding-type power, disposed to provide power to the weld;   power control means for controlling the means for providing such that the power output has a wave shape including arc current portions and short circuit current portions, operatively connected to the means for providing;   wire control means for controlling the means for feeding, operatively connected to the means for feeding, such that process enters short circuit states and arc states; and   means for controlling the heat by controlling a current polarity, connected to the power control means.   
   
   
       73 . A welding-type power supply for short circuit welding comprising:
 means for providing welding-type power, disposed to provide power to the weld; and   control means for controlling power control means and for causing the transitions between the arc current portions and the short circuit portions.   
   
   
       74 . A method of welding, comprising directing a wire having a diameter of 2.4 mm or more to a weld; and applying a welding current of less than 100 amps. 
   
   
       75 . The method of  claim 74 , wherein, applying a current includes applying a current of less than 35 amps. 
   
   
       76 . A method of controlled short circuit welding, comprising providing an arc state and a short circuit state, wherein the current waveform during the arc state includes at least three segments, and the last segment is entered into prior to the short circuit state being entered, and is the same current magnitude as the current magnitude at the start of the short circuit state.