Method for implementing spatter-less welding

• US 8,835,795 B2
• Filed: 11/14/2008
• Issued: 09/16/2014
• Est. Priority Date: 11/14/2008
• Status: Active Grant

• Current Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Buse, Petru Sorin, Westbrook, Ryan Robert, Chen, Larry Henan
• Primary Examiner(s): Ross, Dana
• Assistant Examiner(s): Bae, Gyounghyun
• Application Number:
  US12/271,107
• Publication Number:
  US 20100122968A1
• Time in Patent Office: 2,132 Days
• Field of Search: 219/78.01, 219/80, 219/86.1, 219/87, 219/91.1, 219/91.2, 219/108, 219/110, 219/111, 219/117.1, 219/118, 219/127, 219/130.01, 219/130.32, 219/130.33, 219/130.5, 219/130.51, 219/136, 219/137.R, 901/42
• US Class Current: 219/108
• CPC Class Codes: B23K 11/11 Spot welding
• CPC Class Codes: B23K 11/257 the measured parameter being an electrical current
• CPC Class Codes: Y10S 901/44 inspection

Abstract

A method for optimizing a schedule for impulse welding including generating a weld lobe using a preexisting welding schedule, the schedule prescribing a current, a weld time, and a pressure; identifying an operating window on the weld lobe; analyzing the operating window, the analysis including determining a maximum time range of the operating window, and determining a maximum current range of the operating window; until (i) the determined maximum time range of the operating window is greater than a predetermined percentage of the prescribed weld time of the schedule and (ii) the determined maximum current range is greater than the prescribed current of the schedule, creating additional weld lobes by varying the pressure and repeating the identifying an operating window and the analyzing the operating window steps; and selecting, within the operating window satisfying conditions (i) and (ii), a second schedule including a second weld time, a second current, and a second pressure.

Claims

1. A method for optimizing a schedule for impulse welding, comprising:

generating a weld lobe using a preexisting welding schedule, the schedule prescribing a current, a weld time, and a pressure;

identifying an operating window on the weld lobe;

analyzing the operating window, the analysis including

determining a maximum time range of the operating window, and

determining a maximum current range of the operating window;

until (i) the determined maximum time range of the operating window is greater than a predetermined percentage of the prescribed weld time of the schedule and (ii) the determined maximum current range is greater than the prescribed current of the schedule, creating additional weld lobes by varying the pressure and repeating the identifying an operating window and the analyzing the operating window steps; and

selecting, within the operating window satisfying conditions (i) and (ii), a second schedule including a second weld time, a second current, and a second pressure.

2. The method of claim 1, wherein the maximum time range of the operating window is determined by calculating the difference in time between a weld encompassed by the operating window having the shortest weld time and the weld time of the schedule.

3. The method of claim 1, wherein the maximum current range of the operating window is determined by calculating the difference in current between a weld encompassed by the operating window having the lowest current and a weld encompassed by the operating window have the largest current.

4. The method of claim 1, wherein the predetermined percentage is 20%.

5. The method of claim 1, wherein:

the generating a weld lobe step includes identifying good welds, bad welds, and welds having expulsion; and

the selecting step includes identifying a region within the operating window satisfying conditions (i) and (ii), the region being at least 0.5 kA away from welds having expulsion, at least 1.5 kA away from bad welds, and at least a predetermined percentage of the prescribed weld time away from the bad welds.

6. The method of claim 5, wherein the predetermined percentage is 20%.

7. The method of claim 5, wherein the selecting a second schedule step further includes:

selecting a schedule within the identified region which is farthest from the bad welds.

8. The method of claim 1, further comprising determining a number of pulses and cool cycles to be included in the second weld time.

9. The method of claim 1, wherein the operating window encompasses each weld not having expulsion and generated with a weld time less than the prescribed weld time of the schedule.

10. The method of claim 8, wherein the determining step includes:

determining durations of the determined at least one pulses.