Systems, methods, and apparatuses for monitoring weld quality

• US 9,012,802 B2
• Filed: 10/03/2013
• Issued: 04/21/2015
• 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., Chantry, Bruce J.
• Primary Examiner(s): Vu, David
• Assistant Examiner(s): Nguyen, Cuong B
• Application Number:
  US14/045,004
• Publication Number:
  US 20140027424A1
• Time in Patent Office: 565 Days
• Field of Search: None
• US Class Current: 219/61.5
• CPC Class Codes: B23K 31/02 relating to soldering or welding dip or wave soldering in the manufacture of printed circuits H05K3/34
• CPC Class Codes: B23K 31/12 relating to investigating the properties, e.g. the weldability, of materials
• CPC Class Codes: B23K 9/095 Monitoring or automatic control of welding parameters
• CPC Class Codes: B23K 9/0953 using computing means
• CPC Class Codes: B23K 9/0956 using sensing means, e.g. optical
• CPC Class Codes: G09B 19/24 Use of tools

Abstract

An arc welder including an integrated monitor is disclosed. The monitor is capable of monitoring variables during a welding process and weighting the variables accordingly, 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 evaluating a plurality of welds performed by an automated electric arc welder under substantially the same conditions and according to substantially the same arc welding process by monitoring the automated electric arc welder as the automated electric arc welder performs the plurality of welds according to the arc welding process by creating actual welding parameters between an advancing wire and a workpiece, said arc welding process controlled by command signals to a power supply of said welder, said method comprising:

during each weld;

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

(b) dividing said wave shapes into states;

(c) measuring a selected weld parameter occurring in one of said states at an interrogation rate over a period of time to obtain a data set for said selected weld parameter;

(d) for each period of time, calculating a quality value for said selected weld parameter from said data set;

(e) comparing each quality value to an expected quality value to determine if a difference between said quality value and said expected quality value exceeds a predetermined threshold;

(f) if said difference exceeds said threshold, weighting said quality value with a magnitude weight based on said difference, and weighting said quality value with a time contribution weight based on a time contribution of said state to its wave shape; and

(g) using all of said quality values, including any weighted quality values, obtained during said welding process to determine a quality score for said weld.

2. The method of claim 1, further comprising:

(h) rejecting said weld if its quality score is within a first predefined range of quality scores; and

(i) accepting said weld if its quality score is within a second predefined range of quality scores.

3. The method of claim 1, further comprising:

(h) permanently associating each weld with its corresponding quality score.

4. The method of claim 1, wherein said interrogation rate is 120 kHz.

5. The method of claim 1, wherein said period of time is approximately 250 ms.

6. The method of claim 1, wherein said selected weld parameter is arc current.

7. The method of claim 1, wherein said selected weld parameter is arc voltage.

8. An automated electric arc welder, wherein the automated electric arc welder performs a plurality of welds under substantially the same conditions and according to substantially the same arc welding process;

wherein a monitor monitors the automated electric arc welder as the automated electric arc welder performs the plurality of welds according to the arc welding process by creating actual welding parameters between an advancing wire and a workpiece;

wherein said arc welding process is defined by a series of rapidly repeating wave shapes of command signals for said parameters, each wave shape constituting a weld cycle with a cycle time; and

wherein said monitor comprises;

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

second logic for selecting a specific wave shape state;

third logic for reading a plurality of selected 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 selected weld parameter;

fourth logic for calculating a plurality of quality parameters for each of said states based on said selected weld parameters;

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

sixth logic for weighting said calculated quality parameter with a magnitude weight based on said difference, and weighting said calculated quality parameter 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,

wherein said quality parameters represent an overall quality measurement of said weld.

9. The automated electric arc welder of claim 8, wherein said monitor is integrated with said electric arc welder.

10. An automated electric arc welder, wherein the automated electric arc welder performs a plurality of welds under substantially the same conditions and according to substantially the same arc welding process;

wherein a monitor monitors the automated electric arc welder as the automated electric arc welder performs the plurality welds according to the arc welding process by creating actual welding parameters between an advancing wire and a workpiece;

wherein said arc welding process is defined by a series of rapidly repeating wave shapes of command signals for said parameters, each wave shape constituting a weld cycle with a cycle time and wherein said monitor comprises;

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

second logic for selecting a specific wave shape state;

third logic for reading a plurality of selected 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 selected weld parameter; and

fourth logic for calculating a plurality of quality parameters for each of said states based on said selected weld parameters,

wherein said selected weld parameters include, for each of said states, a count of said measurements taken for each of said selected weld parameters in said period of time, a mean voltage voltage in said period of time, a root mean square voltage RMSV in said period of time, a voltage variance V_var in said period of time, a mean current current in said period of time, a root mean square current RMSI in said period of time, and a current variance I_va, in said period of time,

wherein voltage=a sum of voltages measured in said period of time/said count of voltage measurements,

wherein

19. The automated electric arc welder of claim 10, wherein said monitor is integrated with said electric arc welder.

11. A production line comprising at least one automated electric arc welder, wherein the automated electric arc welder performs a plurality of welds under substantially the same conditions and according to substantially the same arc welding process;

wherein a monitor monitors the automated electric arc welder as the automated electric arc welder performs the plurality of welds according to the arc welding process by creating actual welding parameters between an advancing wire and a workpiece on the production line;

wherein said arc welding process is defined by a series of rapidly repeating wave shapes of command signals for said parameters, each wave shape constituting a weld cycle with a cycle time; and

wherein said monitor comprises;

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

second logic for selecting a specific wave shape state;

third logic for reading a plurality of selected 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 selected weld parameter;

fourth logic for calculating a plurality of quality parameters for each of said states based on said selected weld parameters;

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

sixth logic for weighting said calculated quality parameter with a magnitude weight based on said difference, and weighting said calculated quality parameter 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,

wherein said quality parameters represent an overall quality measurement of said weld.

12. The production line of claim 11, wherein said monitor is integrated with said at least one electric arc welder.

14. The production line of claim 11, further comprising a conveyor for delivering said workpiece to said electric arc welder.

15. The production line of claim 11, wherein the quality parameters for each weld are used to assess whether the weld is acceptable;

wherein if the weld is acceptable, the workpiece is allowed to continue on the production line; and

wherein if the weld is not acceptable, the workpiece is removed from the production line.

16. The production line of claim 11, wherein the quality parameters for each weld are used to assess whether the weld is acceptable;

wherein if the weld is acceptable, the workpiece is allowed to continue on the production line; and

wherein if the weld is not acceptable, the workpiece is diverted from the production line.

17. The production line of claim 16, wherein the workpiece is diverted to a station for manual inspection of the weld.

18. The production line of claim 11, comprising a plurality of automated electric arc welders.

13. A production line comprising at least one automated electric arc welder, wherein the automated electric arc welder performs a plurality of welds under substantially the same conditions and according to substantially the same arc welding process;

wherein a monitor monitors the automated electric arc welder as the automated electric arc welder performs plurality of the welds according to the arc welding process by creating actual welding parameters between an advancing wire and a workpiece on the production line;

wherein said arc welding process is defined by a series of rapidly repeating wave shapes of command signals for said parameters, each wave shape constituting a weld cycle with a cycle time and wherein said monitor comprises;

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

second logic for selecting a specific wave shape state;

third logic for reading a plurality of selected 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 selected weld parameter; and

fourth logic for calculating a plurality of quality parameters for each of said states based on said selected weld parameters,

wherein said selected weld parameters include, for each of said states, a count of said measurements taken for each of said selected weld parameters in said period of time, a mean voltage voltage in said period of time, a root mean square voltage RMSV in said period of time, a voltage variance V_var in said period of time, a mean current current in said period of time, a root mean square current RMSI in said period of time, and a current variance I_var in said period of time,

wherein voltage=a sum of voltages measured in said period of time/said count of voltage measurements,

wherein

20. The production line of claim 13, wherein said monitor is integrated with said at least one electric arc welder.

21. The production line of claim 13, further comprising a conveyor for delivering said workpiece to said electric arc welder.

22. The production line of claim 13, wherein the quality parameters for each weld are used to assess whether the weld is acceptable;

wherein if the weld is acceptable, the workpiece is allowed to continue on the production line; and

wherein if the weld is not acceptable, the workpiece is removed from the production line.

23. The production line of claim 13, wherein the quality parameters for each weld are used to assess whether the weld is acceptable;

wherein if the weld is acceptable, the workpiece is allowed to continue on the production line; and

wherein if the weld is not acceptable, the workpiece is diverted from the production line.

24. The production line of claim 23, wherein the workpiece is diverted to a station for manual inspection of the weld.

25. The production line of claim 13, comprising a plurality of automated electric arc welders.