Resistance Spot Welding Monitoring System and Method

• US 20080041827A1
• Filed: 05/10/2007
• Published: 02/21/2008
• Est. Priority Date: 05/26/2006
• Status: Abandoned Application

• Current Assignee: Chrysler Group LLC (Stellantis NV)
• Original Assignee: Chrysler Group LLC (Stellantis NV)
• Inventors: Grzadzinski, Gerald A., Cerjanec, Daniel, Li, Wei
• Application Number:
  US11/747,069
• Publication Number:
  US 20080041827A1
• Time in Patent Office: Days
• US Class Current: 219/109
• 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 11/255 the measured parameter being a force B23K11/253 takes precedence
• CPC Class Codes: B23K 11/256 the measured parameter being the inter-electrode electrical resistance
• CPC Class Codes: B23K 11/257 the measured parameter being an electrical current
• CPC Class Codes: B23K 11/258 the measured parameter being a voltage
• CPC Class Codes: B23K 31/125 Weld quality monitoring

Abstract

A resistance spot welding monitoring system includes a plurality of sensors coupled to a resistance spot welding system to receive welding data produced during a welding operation. The monitoring system further includes a nugget prediction system. The welding data is indicative of welding parameters used to produce the weld nugget. The nugget prediction system retrieves the welding data and predicts a nugget size based upon the welding data received from the plurality of sensors. Additionally, the nugget prediction system generates a nugget size signal. The monitoring system also includes an indicator that receives the nugget size signal and notifies an operator of a predicted nugget size.

Claims

1. A resistance spot welding monitoring system, comprising:

a plurality of sensors adapted to be coupled to a resistance spot welding system for receipt of welding data, wherein the welding data is indicative of the welding parameters used to produce a weld nugget;

a nugget prediction system coupled to the plurality of sensors and configured to retrieve the welding data, wherein the nugget prediction system is operable to predict a nugget size based upon the welding data received from the plurality of sensors, and to generate a nugget size signal; and

an indicator coupled to the nugget prediction system and operably receiving the nugget size signal, wherein the indicator notifies an operator of a predicted nugget size.

2. The resistance spot welding monitoring system of claim 1, wherein the welding data include electrical energy data and contact area data used to form the weld nugget.

3. The resistance spot welding monitoring system of claim 2, wherein the contact area is a function of a dynamic resistance associated with a welded plurality of materials.

4. The resistance spot welding monitoring system of claim 2, wherein the electrical energy data further comprises:

a welding current and a tip voltage associated with a pair of electrodes of the resistance spot welding system.

5. The resistance spot welding monitoring system of claim 2, wherein the welding data further comprises at least one of the following:

material thickness data;

welding time;

electrode force; and

dynamic resistance.

6. The resistance spot welding monitoring system of claim 1, wherein the nugget prediction system is further operative to determine whether a severe expulsion occurs during a welding operation.

7. The resistance spot welding monitoring system of claim 6, wherein the nugget prediction system ignores the nugget size whenever a severe expulsion is determined.

8. The resistance spot welding monitoring system of claim 6, wherein the nugget prediction system compares a detected expulsion to a predetermined expulsion threshold to determine whether a severe expulsion has occurred.

9. The resistance spot welding monitoring system of claim 8, wherein the detected expulsion is indicative of a sudden drop in dynamic resistance when a dynamic resistance for the weld nugget is compared with at least one previously obtained dynamic resistance.

10. The resistance spot welding monitoring system of claim 1, wherein the nugget prediction system further comprises a user interface configured to allow an operator to input at least one of the welding parameters.

11. The resistance spot welding monitoring system of claim 1, wherein the nugget size is predicted based on

12. A method for monitoring resistance spot welding, comprising:

sensing welding data associated with a welding operation forming a weld nugget within a plurality of materials, wherein the weld data is indicative of welding parameters used to produce the weld nugget;

predicting a nugget size of the weld nugget based upon the welding parameters; and

notifying an operator of a predicted nugget size.

13. The method of claim 12, further comprising:

determining whether a severe expulsion occurred during the welding operation; and

,

ignoring the predicted nugget size whenever the severe expulsion is determined.

14. The method of claim 13, wherein determining whether the severe expulsion occurs further comprises:

comparing a detected expulsion associated with the weld nugget to a predetermined severe expulsion threshold.

15. The method of claim 14, wherein the severe expulsion occurs when a detected expulsion for the weld nugget is above the predetermined severe expulsion threshold.

16. The method of claim 15, wherein the detected expulsion is indicative of a sudden drop in dynamic resistance when a dynamic resistance for the weld nugget is compared with at least one previously obtained dynamic resistance.

17. The method of claim 12, wherein the welding parameters further comprise at least one of the following:

electrical energy;

contact area;

material thickness data associated with each of the plurality of sheet metals;

welding time;

dynamic resistance; and

electrode force.

18. The method of claim 17, wherein the contact area is a function of the dynamic resistance associated with forming the weld nugget.

19. The method of claim 18, wherein the dynamic resistance is determined by

20. The method of claim 12, wherein the nugget size is determined by