Method of automatically setting a welding parameter for mig/mag welding and a controller for performing the method

Abstract

A method of automatically setting a welding parameter for MIG/MAG welding including the following steps:—initiating (S1) a parameter setting welding operation;—measuring (S12) a welding voltage and retrieving (S13) a parameter representing a wire feed speed during said parameter setting welding operation; and—identifying (S14) a second function mapping said welding current to said welding voltage from said measured welding voltage and said retrieved parameter.

What is claimed is: 
     
         1 . A welding controller for automatically setting a welding parameter for MIG/MAG welding comprising:
 a first function identification control block arranged to determine a first function from a detected response welding current and a present wire feed speed, said first function defining a relationship between the welding current and the wire feed speed; and   a wire feed speed control block arranged to determine a desired wire feed speed from the first function provided from first function identification control block and from a desired welding current.   
     
     
         2 . The welding controller according to  claim 1 , further comprising:
 an operator interface arranged to receive operator information about an actual thickness of a workpiece; and   a desired welding current control block arranged to determine the desired welding current from said actual thickness of the workpiece.   
     
     
         4 . The welding controller according to  claim 2 , wherein the operator interface is further arranged to receive operator information about a wire material used in a welding process. 
     
     
         5 . The welding controller according to  claim 2 , wherein the desired welding current control block utilizes a desired welding current mapping function to map the actual thickness of the workpiece to the desired welding current. 
     
     
         6 . The welding controller according to  claim 5 , wherein the desired welding current mapping function is a linear mapping expressed as I=k 1 *T+k 2 *T 2 , where I represents welding current, T represents thickness of a workpiece, and k 1  and k 2  are parameters dependent on a material of the workpiece. 
     
     
         7 . The welding controller according to  claim 2 , wherein the desired welding current control block uses a look up table to define a relationship between the actual thickness of the workpiece and the desired welding current. 
     
     
         8 . The welding controller according to  claim 1 , wherein the first function of the first function identification control block may be a linear mapping expressed as v=k*I p , where v represents wire feed speed, I represents current, and p is a value between 1 and 2. 
     
     
         9 . The welding controller according to  claim 1 , wherein the welding controller includes further control blocks that enable the welding controller to:
 generate, during a parameter setting welding operation, a plurality of data couples, each data couple comprising a welding voltage and a wire feed speed parameter;   identify a second function mapping a relationship between the welding voltage and the wire feed speed parameter based on the data couples, wherein the second function is defined outside of real welding operating points;   determine a welding wire material category using the second function defined outside of the real welding operating points; and   determine a controlling voltage based on wire welding material from said second function.   
     
     
         10 . The welding controller according to  claim 1 , wherein the wire feed speed control block determines the desired wire feed speed by interpolating in a look up table that defines a relationship between welding current and the first function, or by using a third function that defines a relationship between the welding current and the first function. 
     
     
         11 . A MIG/MAG welding apparatus including a power source, an electrode feeder adapted to feed an electrode to a welding torch, and a welding controller arranged to control the welding current and voltage supplied by the power source to the welding torch, wherein said welding controller furthermore includes:
 a welding controller for automatically setting a welding parameter for MIG/MAG welding, the welding controller configured to:
 generate, during a parameter setting welding operation, a plurality of data couples, each data couple comprising a welding voltage and a wire feed speed parameter; 
 identify a second function mapping a relationship between the welding voltage and the wire feed speed parameter based on the data couples, wherein the second function is defined outside of real welding operating points; 
 determine a welding wire material category using the second function defined outside of the real welding operating points; and 
 perform a continued welding process subsequent to the parameter setting welding operation. 
   
     
     
         12 . The MIG/MAG welding apparatus of  claim 11 , further comprising:
 a general controller that is configured to provide a present wire feed speed and a response welding current to the present wire feed speed.   
     
     
         13 . The MIG/MAG welding apparatus of  claim 12 , wherein the welding controller further comprises:
 a first function identification control block arranged to determine a first function from the response welding current and the present wire feed speed.   
     
     
         14 . The MIG/MAG welding apparatus of  claim 12 , wherein the welding controller further comprises:
 a first sensor adapted to sense a short circuit between the electrode and the workpiece; and   a second sensor adapted to sense an arc between the electrode and the workpiece.   
     
     
         15 . The MIG/MAG welding apparatus of  claim 14 , wherein the welding controller further comprises:
 short circuit percentage value determination control block that establishes a short-circuiting time with the first sensor and establishes an arc time with the second sensor, the short circuit percentage value determination control block is further configured to determine a short circuit percentage value.   
     
     
         16 . The MIG/MAG welding apparatus of  claim 15 , wherein the welding controller further comprises:
 a welding voltage reference value determination control block that determines a correctional term for a reference voltage from the short circuit percentage value received from the short circuit percentage value determination control block.   
     
     
         17 . The MIG/MAG welding apparatus of  claim 16 , wherein the general controller receives the reference voltage from the welding voltage reference value determination control block. 
     
     
         18 . The MIG/MAG welding apparatus of  claim 17 , wherein the general controller controls increases voltage supplied to the electrode if a measured short-circuiting time of a period time, where the period time is a sum of the short-circuiting time and the arc time, exceeds a pre-defined value and decreases the voltage supplied to the electrode if the short-circuiting percentage goes below the pre-defined value. 
     
     
         19 . The MIG/MAG welding apparatus of  claim 11 , further comprising:
 a first sensor configured to detect a present wire feed speed; and   a second sensor configured to detect a response welding current to the detected present wire feed speed.   
     
     
         20 . The MIG/MAG welding apparatus of  claim 14 , wherein the welding controller further comprises:
 a first function identification control block arranged to determine a first function from the detected response welding current and the present wire feed speed.