Electric arc welder system with waveform profile control for cored electrodes

Abstract

An electric arc welder for creating a welding process in the form of a succession of AC waveforms between a particular type of cored electrode, with a sheath and core, and a workpiece by a power source comprising an high frequency switching device for creating the individual waveforms in the succession of waveforms, each waveform having a profile is formed by the magnitude of each of a large number of short current pulses generated at a frequency of at least 18 kHz where the profile is determined by the input signal to a wave shaper controlling the short current pulses; a circuit to create a profile signal indicative of the particular type of electrode; and a select circuit to select the input signal based upon the profile signal whereby the wave shaper causes the power source to crate a specific waveform profile for the particular type of cored electrode.

1 . An electric arc welder, comprising: 
 means for identifying a particular type of electrode used in a given welding process;    means for selecting a particular waveform profile according to an identified electrode type;    a power source operative to provide a succession of waveforms between an electrode and a workpiece according to a wave shape signal; and    means for providing the wave shape signal to the power source at least partially according to the selected particular waveform profile;    wherein the selected waveform profile causes a sheath and a core of the identified electrode to melt at about the same rate.    
   
   
       2 . The welder of  claim 1 , wherein the means for identifying the particular type of electrode comprises a reading device that automatically identifies a particular type of electrode used in a given welding process and provides a corresponding electrode type input to the means for selecting a particular waveform.  
   
   
       3 . The welder of  claim 1 , wherein the means for selecting a particular waveform profile comprises: 
 a lookup component receiving an electrode type input from the means for identifying the particular type of electrode and generating a profile output according to the electrode type input and a welding process setpoint;    a select component receiving the profile output from the lookup component and selecting a particular stored waveform profile according to the profile output.    
   
   
       4 . The welder of  claim 1 , wherein the means for providing the wave shape signal comprises a waveform generator receiving a selected particular waveform profile and providing a wave shape signal to the power source at least partially according to the selected particular waveform profile.  
   
   
       5 . The welder of  claim 1 , further comprising a profile control component for setting at least one profile parameter of an individual waveform, the parameters selected from the class consisting of frequency, duty cycle, up ramp rate and down ramp rate.  
   
   
       6 . The welder of  claim 5 , further comprising a magnitude circuit for adjusting the individual waveform to set total current, voltage and/or power without substantially affecting the general fixed profile.  
   
   
       7 . The welder of  claim 1 , wherein the selected waveform profile has a leading edge and a ramp portion at the leading edge to control melting of the sheath.  
   
   
       8 . The welder of  claim 1 , wherein the electrode has an outer diameter and the selected waveform profile controls the arc length between the electrode and the workpiece to about 1.5 times the outer diameter of the electrode or less.  
   
   
       9 . The welder of  claim 1 , wherein the power source provides a succession of AC waveforms between the electrode and the workpiece according to the wave shape signal.  
   
   
       10 . An electric arc welder, comprising: 
 a power source operative to provide a succession of waveforms between an electrode and a workpiece according to a wave shape signal;    a reading device that identifies a particular type of electrode used in a given welding process;    means for selecting a particular waveform profile according to the identified electrode type;    means for providing the wave shape signal to the power source at least partially according to the selected particular waveform profile;    a profile control component for setting at least one profile parameter of an individual waveform, the parameters selected from the class consisting of frequency, duty cycle, up ramp rate and down ramp rate; and    a magnitude circuit for adjusting the individual waveform to set total current, voltage and/or power without substantially affecting the general fixed profile.    
   
   
       11 . The welder of  claim 10 , wherein the selected waveform profile causes a sheath and a core of the identified electrode to melt at about the same rate.  
   
   
       12 . The welder of  claim 10 , wherein the selected waveform profile has a leading edge and a ramp portion at the leading edge to control melting of the sheath.  
   
   
       13 . The welder of  claim 10 , wherein the electrode has an outer diameter and the selected waveform profile controls the arc length between the electrode and the workpiece to about 1.5 times the outer diameter of the electrode or less.  
   
   
       14 . The welder of  claim 10 , wherein the power source provides a succession of AC waveforms between the electrode and the workpiece according to the wave shape signal.  
   
   
       15 . An electric arc welder, comprising: 
 a power source operative to provide a succession of waveforms between an electrode and a workpiece according to a wave shape signal;    a reading device that identifies a particular type of electrode used in a given welding process;    means for selecting a particular waveform profile according to the identified electrode type;    means for providing the wave shape signal to the power source at least partially according to the selected particular waveform profile;    a data store with addressable data blocks each indicative of a specific cored electrode;    a select component with a number of stored waveform signals for setting a given waveform profile in the means for providing the wave shape signal; and    an output component to output a special data block to select a given waveform signal upon selecting the address for the identified electrode type.    
   
   
       16 . The welder of  claim 15 , wherein the waveforms are AC waveforms individually comprising a positive portion with a first shape and having a first time, and a negative portion with a second shape and having a second time, wherein one of the first and second shapes is greater in magnitude than the other of the shapes, and wherein the time of the shape with the greater magnitude is substantially less than the time of the other shape.  
   
   
       17 . The welder of  claim 15 , further comprising a set point storage device including a plurality of data blocks individually indicative of a specific wire feed speed set point, wherein the select component is responsive to both the data block outputted from the data store and the set point storage device.  
   
   
       18 . The welder of  claim 15 , wherein the given waveform profile causes the sheath and core to melt at about the same rate.  
   
   
       19 . The welder of  claim 15 , wherein the output component outputs the special data block to select the given waveform signal upon selecting the address according to the particular cored electrode and according to a wire feed speed of the welding process.  
   
   
       20 . The welder of  claim 15 , wherein the electrode has an outer diameter and the selected waveform profile controls the arc length between the electrode and the workpiece to about 1.5 times the outer diameter of the electrode or less.