RESISTANCE SPOT WELD HEAD WITH INTEGRATED ACCELEROMETER

• US 20190314925A1
• Filed: 04/12/2018
• Published: 10/17/2019
• Est. Priority Date: 04/12/2018
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Schultz, Steven J., Gronneberg-Schnoes, Nicholas A., Hartung, John E., Yakovlev, Vadim A., Nikrin, Peter, Tuominen, Scott N., Westenberg, Enrico, Weiss, Jeffrey P.
• Granted Patent: US 11,224,932 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 11/11 Spot welding
• CPC Class Codes: B23K 11/115 by means of two electrodes placed opposite one another on both sides of the welded parts
• CPC Class Codes: B23K 11/25 Monitoring devices
• CPC Class Codes: B23K 11/253 the measured parameter being a displacement or a position
• CPC Class Codes: B23K 31/125 Weld quality monitoring
• CPC Class Codes: B23K 9/22 Percussion welding
• CPC Class Codes: G01P 15/122 by metal resistance strain gauges, e.g. wire resistance strain gauges

Abstract

Aspects of this disclosure relate to a welding system that is configured to execute opposed, step, and parallel gap resistance spot welds (RSW) and associated methods. The system may be configured to switch bases to switch between an opposed weld configuration, a step weld configuration, and a parallel gap configuration. The system may include an accelerometer that is secured to the weld head adjacent one of the electrodes. The system may use the accelerometer to determine whether or not an RSW was defective. Acceleration data may indicate a defective weld when it includes acceleration data that is outside of a threshold range of acceptable acceleration data.

Claims

1. An apparatus comprising:

a resistance spot weld (RSW) head that defines a PGW configuration and an opposed welding configuration, the RSW head comprising;

one or more processing circuits;

a first electrode and a second electrode, wherein the first electrode and the second electrode are configured to execute a parallel gap RSW (PGW) on a first set of components secured to a first base when the RSW head is in the PGW configuration, wherein the first electrode is configured to execute an opposed RSW (opposed weld) with a third electrode of a second base on a second set of components secured to the second base when the RSW head is in the opposed welding configuration; and

an accelerometer securely attached to the first electrode at a location adjacent to the first electrode, wherein the one or more processing circuits are configured to cause the accelerometer to gather a PGW set of acceleration data of the first electrode during the PGW and gather an opposed weld set of acceleration data of the first electrode during the opposed weld,

wherein the one or more processing circuits are configured to determine that the PGW set of acceleration data indicates a first welding defect based on the PGW set of acceleration data including at least one acceleration value outside of a first threshold acceleration range, and

wherein the one or more processing circuits are configured to determine that the opposed weld set of acceleration data indicates a second welding defect based on the opposed weld set of acceleration data including at least one acceleration value outside of a second threshold acceleration range.

2. The apparatus of claim 1, wherein both the first threshold acceleration range and the second first threshold acceleration range includes different upper and lower threshold limits for different time periods of RSWs.

3. The apparatus of claim 1, wherein the one or more processing circuits are configured to analyze a first portion of the PGW set and opposed weld set of acceleration data to determine that the PGW set and opposed weld set of acceleration data indicate the first welding defect and the second welding defect, wherein the first potion includes relatively less volatility of acceleration data than a subsequent second portion of the PGW set and opposed weld set of acceleration data.

4. The apparatus of claim 3, wherein the first portion includes a first 0.003 seconds of the PGW set and the opposed weld set of acceleration data.

5. The apparatus of claim 3, wherein the one or more processing circuits are configured to analyze a prognostic portion of the first portion of the PGW set and opposed weld set of acceleration data to determine that the PGW set and opposed weld set of acceleration data indicate the first welding defect and the second welding defect.

6. The apparatus of claim 5, wherein the prognostic portion is between 0.0015 seconds and 0.003 seconds of the PGW set and opposed weld set of acceleration data.

7. The apparatus of claim 1, wherein:

the first electrode and the second electrode are configured to execute another PGW on a third set of components secured to the first base when the RSW head is in the PGW configuration;

the one or more processing circuits are configured to cause the accelerometer to gather a third set of acceleration data of the first electrode during the another PGW;

the one or more processing circuits are configured to determine that the third set of acceleration data does not indicate a welding defect by comparing acceleration values of the third set of acceleration data against the first threshold acceleration range;

the one or more processing circuits are configured to determine a first derived set of acceleration data by determining a first derivative of acceleration values of the third set of acceleration data; and

the one or more processing circuits are configured to determine that the first derived set of acceleration data indicates a third welding defect by including at least one derived acceleration value outside of a threshold derived acceleration range.

8. The apparatus of claim 1, wherein:

the first electrode is configured to execute another opposed weld with the third electrode of the second base on a fourth set of components secured to the second base when the RSW head is in the opposed welding configuration;

the one or more processing circuits are configured to cause the accelerometer to gather a fourth set of acceleration data of the first electrode during the another opposed weld;

the one or more processing circuits are configured to determine that the fourth set of acceleration data does not indicate a welding defect by comparing acceleration values of the fourth set of acceleration data against the second threshold acceleration range;

the one or more processing circuits are configured to determine a second derived set of acceleration data by determining a first derivative of acceleration values of the fourth set of acceleration data; and

the one or more processing circuits are configured to determine that the second derived set of acceleration data indicates a fourth welding defect by including at least one derived acceleration value outside of a threshold derived acceleration range.

9. The apparatus of claim 1, wherein the RSW head is configured to execute the PGW by moving both the first electrode and the second electrode toward the first base and wherein the RSW head is configured to execute the opposed weld by moving the first electrode toward the second base.

10. The apparatus of claim 1, further comprising a first arm that is configured to receive the first electrode and a second arm that is configured to receive the second electrode, wherein the first arm and the second arm are fixedly connected secured to the RSW head by a set of securing mechanisms that extend through apertures of the first arm and the second arm and extend into apertures of the RSW head.

11. The apparatus of claim 1, wherein the first electrode and the second electrode define a cross-sectional area of approximately 1.015 millimeters by 0.635 millimeters at a tip that is configured to contact the first and second set of components.

12. The apparatus of claim 1, the RSW head including a removal mechanism, wherein:

the one or more processing circuits are configured to cause the removal mechanism to physically remove the first set of components from the first base to a predetermined defect location based on the one or more processing circuits determining that the PGW set of acceleration data indicates the first welding defect; and

the one or more processing circuits are configured to cause the removal mechanism to physically remove the second set of components from the second base to the predetermined defect location based on the one or more processing circuits determining that the opposed weld set of acceleration data indicates the second welding defect.

13. The apparatus of claim 1, further comprising a display, wherein:

the one or more processing circuits are configured to cause the display to provide an indication of the first welding defect based on the one or more processing circuits determining that the PGW set of acceleration data indicates the first welding defect; and

the one or more processing circuits are configured to cause the display to provide an indication of the second welding defect based on the one or more processing circuits determining that the opposed weld set of acceleration data indicates the second welding defect.

14. The apparatus of claim 1, wherein the accelerometer is mounted to the first electrode at the location adjacent to the first electrode using one or more magnets.

15. The apparatus of claim 1, wherein the RSW head defines a step welding configuration and further comprises a third electrode that is interchangeable with the second electrode and is relatively longer than the second electrode,

wherein the first electrode and the third electrode are configured to execute a step RSW (step weld) on a third set of components secured to the first base when the RSW head is in the step welding configuration,

wherein the one or more processing circuits are configured to cause the accelerometer to gather a step weld set of acceleration data of the first electrode during the step weld,

wherein the one or more processing circuits are configured to determine that the step weld set of acceleration data indicates a third welding defect based on the step weld set of acceleration data including at least one acceleration value outside of a third threshold acceleration range.

16. A welding system comprising:

a computing device that comprises;

one or more processing circuits; and

a display,

a resistance spot weld (RSW) head that defines a PGW configuration and an opposed welding configuration, the RSW head comprising;

a first arm that is configured to receive a first electrode;

a second arm that is configured to receive a second electrode; and

an accelerometer securely attached to the first electrode at a location adjacent to the first electrode;

a first base with a first securing platform configured to secure a first set of components; and

a second base with a second securing platform configured to secure a second set of components and including a third electrode for opposed RSW (opposed weld),

wherein the first electrode and the second electrode are configured to execute a parallel gap RSW (PGW) on the first set of components as secured to the first base when the RSW head is in the PGW configuration,

wherein the first electrode and the third electrode are configured to execute an opposed weld on the second set of components as secured to the second base when the RSW head is in the opposed welding configuration,

wherein the one or more processing circuits are configured to cause the accelerometer to gather a PGW set of acceleration data of the first electrode during the PGW and gather an opposed weld set of acceleration data of the first electrode during the opposed weld,

wherein the one or more processing circuits are configured to indicate a first welding defect of the first set of components on the display based on determining that a first portion of the PGW set of acceleration data indicates the first welding defect by including at least one acceleration value outside of a threshold acceleration range, wherein the first portion includes relatively less volatility of acceleration data than a subsequent second portion of the PGW set of acceleration data, and

wherein the one or more processing circuits are configured to indicate a second welding defect of the second set of components on the display based on determining that a first portion of the opposed weld set of acceleration data indicates the second welding defect by including at least one acceleration value outside of the threshold acceleration range, wherein the first portion of the opposed weld set of acceleration data includes relatively less volatility of acceleration data than a subsequent second portion of the opposed weld set of acceleration data.

17. The welding system of claim 16, wherein the first portion of the PGW set of acceleration data includes a first 0.001 seconds of the PGW and the first portion of the opposed weld set of acceleration data includes a first 0.001 seconds of the opposed weld.

18. The welding of claim 16, wherein the one or more processing circuits are configured to analyze a prognostic portion of the first portion of the PGW set and opposed weld set of acceleration data to determine that the first and opposed weld set of acceleration data indicate the first and the second welding defect.

19. The welding of claim 16, wherein the prognostic portion is between 0.0005 seconds and 0.001 seconds of the PGW of the PGW set of acceleration data and between 0.0005 seconds and 0.001 seconds of the opposed weld of the opposed weld set of acceleration data.

20. The welding system of claim 16, wherein:

the first electrode and the second electrode are configured to execute another PGW on a third set of components secured to the first base when the RSW head is in the PGW configuration;

the one or more processing circuits are configured to cause the accelerometer to gather a third set of acceleration data of the first electrode during the another PGW;

the one or more processing circuits are configured to determine that the third set of acceleration data does not indicate a welding defect by comparing acceleration values of the third set of acceleration data against the threshold acceleration range;

the one or more processing circuits are configured to determine a first derived set of acceleration data by determining a first derivative of acceleration values of the third set of acceleration data; and

the one or more processing circuits are configured to determine that the first derived set of acceleration data indicates a third welding defect by including at least one derived acceleration value outside of a threshold derived acceleration range.

21. The welding system of claim 16, wherein:

the first electrode is configured to execute another opposed weld with the third electrode of the second base on a fourth set of components secured to the second base when the RSW head is in the opposed welding configuration;

the one or more processing circuits are configured to cause the accelerometer to gather a fourth set of acceleration data of the first electrode during the another opposed weld;

the one or more processing circuits are configured to determine that the fourth set of acceleration data does not indicate a welding defect by comparing acceleration values of the fourth set of acceleration data against the threshold acceleration range;

the one or more processing circuits are configured to determine a second derived set of acceleration data by determining a first derivative of acceleration values of the fourth set of acceleration data; and

the one or more processing circuits are configured to determine that the second derived set of acceleration data indicates a fourth welding defect by including at least one derived acceleration value outside of a threshold derived acceleration range.

22. The welding system of claim 16, wherein the RSW head is configured to execute the PGW by being moved toward the first base and enabling both the first arm receiving the first electrode and the second arm receiving the second electrode to move relative to the RSW head during the PGW and wherein the RSW head is configured to execute the opposed weld by moving the RSW head toward the second base and enabling the first arm receiving the first electrode to move relative to the RSW head during the opposed weld.

23. A method of welding comprising:

executing a parallel gap resistance spot weld (RSW)to a first set of components secured to a first base with a welding system that includes one or more processing circuits and a weld head and a first and second electrode secured to the weld head by providing current to the first electrode and enabling the current to exit through the second electrode when the first and second electrodes are contacting the first set of components;

gathering, by an accelerometer secured to the weld head, a PGW set of acceleration data of the first electrode during the period of time during which the first electrode provided current to the first set of components;

determining, by the one or more processing circuits, that the PGW set of acceleration data indicates a first welding defect by identifying that the PGW set of acceleration data includes at least one acceleration value outside of a first threshold acceleration range;

executing, with the welding system, an opposed RSW (opposed weld) to a second set of components secured to a second base that includes a third electrode, the opposed weld executed by providing current to the first electrode and enabling the current to exit through the third electrode when the first electrode and the third electrode are contacting the second set of components;

gathering, by the accelerometer, an opposed weld set of acceleration data of the first electrode during the period of time during which the first electrode provided current to the second set of components; and

determining, by the one or more processing circuits, that the opposed weld set of acceleration data indicates a second welding defect by identifying that the opposed weld set of acceleration data includes at least one acceleration value outside of a second threshold acceleration range.

24. The method of claim 23, wherein both the first threshold acceleration range and the second threshold acceleration range include different upper and lower threshold limits for different time periods of RSWs.

25. The method of claim 23, wherein the one or more processing circuits are configured to analyze a first portion of the PGW set and opposed weld set of acceleration data to determine that the PGW set and opposed weld set of acceleration data indicate the first welding defect and the second welding defect, wherein the first potion includes relatively less volatility of acceleration data than a subsequent second portion of the PGW set and opposed weld set of acceleration data.

26. The method of claim 25, wherein the first portion includes a first 0.003 seconds of the PGW set and the opposed weld set of acceleration data.

27. The method of claim 25, wherein the one or more processing circuits are configured to analyze a prognostic portion of the first portion of the PGW set and opposed weld set of acceleration data to determine that the PGW set and opposed weld set of acceleration data indicate the first welding defect and the second welding defect.

28. The method of claim 27, wherein the prognostic portion is between 0.0015 seconds and 0.003 seconds of the PGW set and opposed weld set of acceleration data.