SYSTEMS, METHODS, AND APPARATUSES FOR MONITORING WELD QUALITY

• US 20120205359A1
• Filed: 04/23/2012
• Published: 08/16/2012
• Est. Priority Date: 11/13/2009
• Status: Active Grant

• Current Assignee: Lincoln Global Incorporated (Lincoln Electric Holdings Incorporated)
• Original Assignee: Lincoln Global Incorporated (Lincoln Electric Holdings Incorporated)
• Inventors: Daniel, Joseph A.
• Granted Patent: US 8,884,177 B2
• Time in Patent Office: Days
• US Class Current: 219/130.01
• CPC Class Codes: B23K 31/12 relating to investigating the properties, e.g. the weldability, of materials
• CPC Class Codes: B23K 9/0953 using computing means

Abstract

An arc welding system and methods. The system is capable of monitoring variables during a welding process, according to wave shape states, and weighting the variables accordingly, detecting defects of a weld, diagnosing possible causes of the defects, quantifying overall quality of a weld, obtaining and using data indicative of a good weld, improving production and quality control for an automated welding process, teaching proper welding techniques, identifying cost savings for a welding process, and deriving optimal welding settings to be used as pre-sets for different welding processes or applications.

Claims

1. A method of diagnosing an arc welding process by monitoring an electric arc welder as the welder performs the arc welding process by creating actual welding parameters between an advancing wire and a workpiece to create a weld, said welding process controlled by command signals to a power supply of said welder, said method comprising:

generating a series of rapidly repeating wave shapes, each wave shape constituting a weld cycle with a cycle time;

dividing said wave shapes into states;

measuring a plurality of weld parameters occurring in one or more of said states at an interrogation rate over a period of time repeatedly during said welding process;

calculating a plurality of quality parameters for each of said one or more states based on said measurements of said weld parameters during said welding process; and

analyzing at least one of said plurality of quality parameters and said plurality of weld parameters to diagnose said arc welding process by determining one or more possible causes of one or more localized or continuous defects of the weld.

2. The method of claim 1, further comprising:

comparing a value of each of said quality parameters calculated for each period of time to a corresponding expected quality parameter value to determine if a difference between said calculated quality parameter value and said expected quality parameter value exceeds a predetermined threshold; and

if said difference exceeds said threshold, weighting said calculated quality parameter value with a magnitude weight based on said difference, and weighting said calculated quality parameter value with a time contribution weight based on a time contribution of its state to the wave shape including said state.

3. The method of claim 1, wherein said plurality of weld parameters include, for one or more of said states, two or more of an arc current, an arc voltage, a wire feed speed, a temperature of said workpiece, a level of a shielding gas, a composition of a shielding gas, a wind speed near said workpiece, a humidity level near said workpiece, and an operator position.

4. The method of claim 1, wherein said plurality of weld parameters include, for one or more of said states, two or more of a torch position, a level of sound produced by said arc welding process, at least one frequency of sound produced by said arc welding process, a pulsing rate of sound produced by said arc welding process, a level of visible light produced by said arc welding process, at least one frequency of visible light produced by said arc welding process, a pulsing rate of visible light produced by said arc welding process, a level of infrared light produced by said arc welding process, at least one frequency of infrared light produced by said arc welding process, a pulsing rate of infrared light produced by said arc welding process, and a wire feed motor current level.

5. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, two or more of a quality count average (QCA), a quality count standard deviation (QCSD), a quality voltage average (QVA), a quality voltage standard deviation (QVSD), a quality current average (QIA), a quality current standard deviation (QISD), a quality voltage variance average (QVVA), a quality voltage variance standard deviation (QVVSD), a quality current variance average (QIVA), and a quality current variance standard deviation (QIVSD).

6. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality wire feed speed average (QWA), a quality wire feed speed standard deviation (QWSD), a quality wire feed speed variance average (QWVA), and a quality wire feed speed variance standard deviation (QWVSD).

7. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality sound level average (QSLA), a quality sound level standard deviation (QSLSD), a quality sound level variance average (QSLVA), and a quality sound level variance standard deviation (QSLVSD).

8. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality sound frequency average (QSFA), a quality sound frequency standard deviation (QSFSD), a quality sound frequency variance average (QSFVA), and a quality sound frequency variance standard deviation (QSFVSD).

9. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality sound pulse rate average (QSPRA), a quality sound pulse rate standard deviation (QSPRSD), a quality sound pulse rate variance average (QSPRVA), and a quality sound pulse rate variance standard deviation (QSPRVSD).

10. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality visible light level average (QVLLA), a quality visible light level standard deviation (QVLLSD), a quality visible light level variance average (QVLLVA), and a quality visible light level variance standard deviation (QVLLVSD).

11. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality visible light frequency average (QVLFA), a quality visible light frequency standard deviation (QVLFSD), a quality visible light frequency variance average (QVLFVA), and a quality visible light frequency variance standard deviation (QVLFVSD).

12. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality visible light pulse rate average (QVLPRA), a quality visible light pulse rate standard deviation (QVLPRSD), a quality visible light pulse rate variance average (QVLPRVA), and a quality visible light pulse rate variance standard deviation (QVLPRVSD).

13. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality infrared light level average (QIRLLA), a quality infrared light level standard deviation (QIRLLSD), a quality infrared light level variance average (QIRLLVA), and a quality infrared light level variance standard deviation (QIRLLVSD).

14. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality infrared light frequency average (QIRLFA), a quality infrared light frequency standard deviation (QIRLFSD), a quality infrared light frequency variance average (QIRLFVA), and a quality infrared light frequency variance standard deviation (QIRLFVSD).

15. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality infrared light pulse rate average (QIRLPRA), a quality infrared light pulse rate standard deviation (QIRLPRSD), a quality infrared light pulse rate variance average (QIRLPRVA), and a quality infrared light pulse rate variance standard deviation (QIRLPRVSD).

16. The method of claim 1, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality wire feed motor current average (QWFMIA), a quality wire feed motor current standard deviation (QWFMISD), a quality wire feed motor current variance average (QWFMIVA), and a quality wire feed motor current variance standard deviation (QWFMIVSD).

17. The method of claim 1, wherein said one or more defects include one or more of gas inclusions in the weld (porosity, blow holes, worm holes), burnthrough of the workpiece, lack of penetration into the workpiece, splatter, an underfilled joint, undercut, cracking of the weld, voids in the weld, and lack of fusion.

18. The method of claim 1, wherein said one or more possible causes include one or more of a lack of shielding gas, a short contact tip to work distance, a long contact tip to work distance, a clogged nozzle, workpiece surface contamination, too slow a travel speed, too fast a travel speed, too slow a wire feed speed, too fast a wire feed speed, sulfur content in the workpiece or electrode, excessive moisture from the electrode or workpiece, and too small of an electrode angle.

19. A system for diagnosing an arc welding process by monitoring an electric arc welder as the welder performs the arc welding process by creating actual welding parameters between an advancing wire and a workpiece to form a weld, said welding process defined by a series of rapidly repeating wave shapes controlled by command signals to a power supply of the welder, said system comprising:

a logic state controller for segmenting each of said wave shapes into a series of time segmented states;

a circuit for selecting a specific wave shape state;

monitoring devices for monitoring a plurality of weld parameters occurring in one or more of said states at an interrogation rate over a period of time repeated during the welding process to obtain a data set for said plurality of weld parameters;

a circuit for calculating a plurality of quality parameters for each of said states based on said monitored plurality of weld parameters; and

a diagnostic logic circuit for analyzing at least one of said plurality of quality parameters and said plurality of weld parameters to diagnose said arc welding process by determining one or more possible causes of one or more localized or continuous defects of the weld.

20. The system of claim 19, further comprising:

a circuit for comparing a value of each of said quality parameters calculated for each period of time to a corresponding expected quality parameter value to determine if a difference between said calculated quality parameter value and said expected quality parameter value exceeds a predetermined threshold; and

a circuit for weighting said calculated quality parameter value with a magnitude weight based on said difference, and weighting said calculated quality parameter value with a time contribution weight based on a time contribution of its state to the wave shape including said state, if said difference exceeds said threshold.

21. The system of claim 19, wherein said plurality of weld parameters include, for one or more of said states, two or more of an arc current, an arc voltage, a wire feed speed, a temperature of said workpiece, a level of a shielding gas, a composition of a shielding gas, a wind speed near said workpiece, a humidity level near said workpiece, and an operator position.

22. The system of claim 19, wherein said plurality of weld parameters include, for one or more of said states, two or more of a torch position, a level of sound produced by said welding process, a frequency of sound produced by said welding process, a pulsing rate of sound produced by said arc welding process, a level of visible light produced by said arc welding process, a frequency of visible light produced by said arc welding process, a pulsing rate of visible light produced by said arc welding process, a level of infrared light produced by said arc welding process, a frequency of infrared light produced by said arc welding process, a pulsing rate of infrared light produced by said arc welding process, and a wire feed motor current level.

23. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, two or more of a quality count average (QCA), a quality count standard deviation (QCSD), a quality voltage average (QVA), a quality voltage standard deviation (QVSD), a quality current average (QIA), a quality current standard deviation (QISD), a quality voltage variance average (QVVA), a quality voltage variance standard deviation (QVVSD), a quality current variance average (QIVA), and a quality current variance standard deviation (QIVSD).

24. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality wire feed speed average (QWA), a quality wire feed speed standard deviation (QWSD), a quality wire feed speed variance average (QWVA), and a quality wire feed speed variance standard deviation (QWVSD).

25. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality sound level average (QSLA), a quality sound level standard deviation (QSLSD), a quality sound level variance average (QSLVA), and a quality sound level variance standard deviation (QSLVSD).

26. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality sound frequency average (QSFA), a quality sound frequency standard deviation (QSFSD), a quality sound frequency variance average (QSFVA), and a quality sound frequency variance standard deviation (QSFVSD).

27. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality sound pulse rate average (QSPRA), a quality sound pulse rate standard deviation (QSPRSD), a quality sound pulse rate variance average (QSPRVA), and a quality sound pulse rate variance standard deviation (QSPRVSD).

28. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality visible light level average (QVLLA), a quality visible light level standard deviation (QVLLSD), a quality visible light level variance average (QVLLVA), and a quality visible light level variance standard deviation (QVLLVSD).

29. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality visible light frequency average (QVLFA), a quality visible light frequency standard deviation (QVLFSD), a quality visible light frequency variance average (QVLFVA), and a quality visible light frequency variance standard deviation (QVLFVSD).

30. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality visible light pulse rate average (QVLPRA), a quality visible light pulse rate standard deviation (QVLPRSD), a quality visible light pulse rate variance average (QVLPRVA), and a quality visible light pulse rate variance standard deviation (QVLPRVSD).

31. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality infrared light level average (QIRLLA), a quality infrared light level standard deviation (QIRLLSD), a quality infrared light level variance average (QIRLLVA), and a quality infrared light level variance standard deviation (QIRLLVSD).

32. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality infrared light frequency average (QIRLFA), a quality infrared light frequency standard deviation (QIRLFSD), a quality infrared light frequency variance average (QIRLFVA), and a quality infrared light frequency variance standard deviation (QIRLFVSD).

33. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality infrared light pulse rate average (QIRLPRA), a quality infrared light pulse rate standard deviation (QIRLPRSD), a quality infrared light pulse rate variance average (QIRLPRVA), and a quality infrared light pulse rate variance standard deviation (QIRLPRVSD).

34. The system of claim 19, wherein said plurality of quality parameters include, for one or more of said states over said period of time, a quality wire feed motor current average (QWFMIA), a quality wire feed motor current standard deviation (QWFMISD), a quality wire feed motor current variance average (QWFMIVA), and a quality wire feed motor current variance standard deviation (QWFMIVSD).

35. The system of claim 19, wherein said one or more defects include one or more of gas inclusions in the weld, burnthrough of the workpiece, lack of penetration into the workpiece, splatter, an underfilled joint, undercut, cracking of the weld, voids in the weld, and lack of fusion.

36. The system of claim 19, wherein said one or more possible causes include one or more of a lack of shielding gas, a short contact tip to work distance, a long contact tip to work distance, a clogged nozzle, workpiece surface contamination, too slow a travel speed, too fast a travel speed, too slow a wire feed speed, too fast a wire feed speed, sulfur content in the workpiece or electrode, excessive moisture from the electrode or workpiece, and too small of an electrode angle.