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; detecting (S2) a response welding current at a present wire feed speed during said parameter setting welding operation; determining (S4) a first function mapping said response welding current to said set wire feed speed; determining (S7) a desired wire feed speed from said first function and said desired welding current.

What is claimed is: 
     
         1 . A welding controller for automatically setting a welding parameter for MIG/MAG welding comprising:
 a plurality of sensors configured to detect a response welding current and a present wire feed speed during a paramter setting welding operation intiated by the welding controller and to enable the welding controller to collect the response welding current and the present wire feed speed as a plurality of data couples, wherein a given data couple of the plurality of data couples defines an operating point in a welding current/wire feed speed space;   a first function identification control block configured to identify a first function that maps a welding current to a wire feed speed from said response welding current and said present wire feed speed, the first function control block identifies the first function by comparing the plurality of data couples to a set of stored functions including the first function, wherein the first function best represents the plurality of data couples; 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.   
     
     
         3 . 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. 
     
     
         4 . 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. 
     
     
         5 . The welding controller according to  claim 4 , 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 the workpiece, and k 1  and k 2  are parameters dependent on a material of the workpiece. 
     
     
         6 . 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. 
     
     
         7 . 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 the welding current and the first function, or by using a third function that defines the relationship between the welding current and the first function. 
     
     
         8 . A welding controller for automatically setting a welding parameter for MIG/MAG welding comprising:
 a general controller configured to detect a response welding current and a present wire feed speed during a paramter setting welding operation intiated by the welding controller and to enable the welding controller to collect the response welding current and the present wire feed speed as a plurality of data couples, wherein a given data couple of the plurality of data couples defines an operating point in a welding current/wire feed speed space;   a first function identification control block configured to identify a first function that maps a welding current to a wire feed speed from said response welding current and said present wire feed speed, the first function control block identifies the first function by comparing the plurality of data couples to a set of stored functions including the first function, wherein the first function best represents the plurality of data couples; 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.   
     
     
         9 . The welding controller according to  claim 8 , 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.   
     
     
         10 . The welding controller according to  claim 9 , wherein the operator interface is further arranged to receive operator information about a wire material used in a welding process. 
     
     
         11 . The welding controller according to  claim 9 , 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. 
     
     
         12 . The welding controller according to  claim 11 , 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 the workpiece, and k 1  and k 2  are parameters dependent on a material of the workpiece. 
     
     
         13 . A MIG/MAG welding apparatus comprising:
 a power source;   an electrode feeder adapted to feed an electrode to a welding torch; and   a welding controller for automatically setting a welding parameter for MIG/MAG welding and arranged to control welding current and voltage supplied by the power source to the welding torch, the welding controller configured to:
 initiate a parameter setting welding operation; 
 detect a response welding current and a present wire feed speed during said parameter setting welding operation; 
 collecting the response welding current and the present wire feed speed as a plurality of data couples, wherein a given data couple of the plurality of data couples defines an operating point in a welding current/wire feed speed space; 
 identify a first function mapping a welding current to a wire feed speed from said response welding current and said present wire feed speed, the identifying comprises comparing the plurality of data couples to a set of stored functions including the first function, wherein the first function best represents the plurality of data couples; 
 determine a desired welding current; and 
 determine a desired wire feed speed from said first function and said desired welding current. 
   
     
     
         14 . The MIG/MAG welding apparatus of  claim 13 , further comprising:
 a first sensor configured to detect the present wire feed speed; and   a second sensor configured to detect the response welding current of the present wire feed speed.   
     
     
         15 . The MIG/MAG welding apparatus of  claim 13 , further comprising:
 a general controller that is configured to provide the present wire feed speed and the response welding current of the present wire feed speed.   
     
     
         16 . The MIG/MAG welding apparatus of  claim 15 , wherein the welding controller further comprises:
 a first sensor adapted to sense a short circuit between the electrode and a workpiece; and   a second sensor adapted to sense an arc between the electrode and the workpiece.   
     
     
         17 . The MIG/MAG welding apparatus of  claim 16 , 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.   
     
     
         18 . The MIG/MAG welding apparatus of  claim 17 , 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.   
     
     
         19 . The MIG/MAG welding apparatus of  claim 18 , wherein the general controller receives the reference voltage from the welding voltage reference value determination control block. 
     
     
         20 . The MIG/MAG welding apparatus of  claim 19 , 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 circuit percentage value goes below the pre-defined value.