Welding Process for the Welding of Aluminum

• US 20140183168A1
• Filed: 12/24/2013
• Published: 07/03/2014
• Est. Priority Date: 12/27/2012
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Arndt, Volker, Haeufgloeckner, Juergen, Ripper, Michael
• Granted Patent: US 9,884,386 B2
• Time in Patent Office: Days
• US Class Current: 219/86.51
• 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 11/185 of aluminium or aluminium alloys
• CPC Class Codes: B23K 11/255 the measured parameter being a force B23K11/253 takes precedence

Abstract

A welding process for the welding of aluminium includes a force sensor measuring a force between two welding electrodes on aluminum elements to be welded and transmitting its measured values to a welding control. Until the elapse of a set welding time, the welding control calculates and stores at least one absolute value and/or at least one increase in the measured force. The welding control compares the measured absolute value and/or the increase in the measured force with a reference value and/or a reference curve and calculates a control deviation from the comparison. After the elapse of the set welding time, the welding control subjects the welding electrodes to a constant current during a welding time extension that follows the set welding time, dependent on a magnitude of the control deviation that is measured at the point in time of the elapse and/or during the set welding time.

Claims

1. A welding process for welding aluminum, comprising:

measuring a force between two welding electrodes on aluminum elements to be welded with at least one force sensor and transmitting the measured force value to a welding control;

until a set welding time elapses, calculating and storing with the welding control during and/or after elapse of predeterminable incremental time frames at least one of at least one absolute value and at least one increase in the measured force;

comparing with the welding control the at least one of the at least one absolute value and the at least one increase in the measured force in each case with at least one of a reference value and a reference curve;

calculating a control deviation resulting from the comparison; and

after the elapse of the set welding time, subjecting the welding electrodes to a current of a constant level during a welding time extension that follows the set welding time, the current of the constant level being dependent on a magnitude of the control deviation that is calculated at a point in time of the elapse and/or during the set welding time.

2. The welding process according to claim 1, further comprising:

during the set welding time, subjecting the two welding electrodes to a differing current level, depending on the magnitude of the control deviation, the differing current level being kept constant during each incremental time frame.

3. The welding process according to claim 1, further comprising:

comparing a variation of the measured force over time during the set welding time that is stored by the welding control with a set variation over time stored in the welding control; and

depending on the resultant control deviation, determining at least one of a length of the welding time extension and the current level during the welding time extension with the welding control.

4. The welding process according to claim 1, wherein:

the force sensor is arranged on one of welding tongs and a drive of welding tongs, and

the force sensor is connected to an analog input of the welding control.

5. The welding process according to claim 1, wherein the constant level of the current during the welding time extension is at least 0.7 times and at most 1.3 times an elapse current level applied to the welding electrodes at the point in time of the elapse of the set welding time.

6. The welding process according claim 1, wherein the incremental time frames have a duration of at least 700 ms and at most 1300 ms.

7. The welding process according to claim 1, further comprising:

performing a spatter detection in an incremental time frame of at least 700 ms and at most 1300 ms during the set welding time using an inspection device to check whether welding spatter has occurred.

8. A welding process according to claim 7, further comprising:

upon detection of welding spatter, continuing the welding operation with a current adjustment sequence that is characteristic of the detection.

9. The welding process according to claim 7, further comprising:

setting and/or activating at least one of a control function of the welding control and a detection function of the inspection mechanism with an operating element.

11. The welding process according to claim 5, wherein the constant level of the current during the welding time extension is at least 0.8 times and at most 1.2 times the elapse current level applied to the welding electrodes at the point in time of the elapse of the set welding time.

12. The welding process according claim 6, wherein the incremental time frames have a duration of at least 800 ms and at most 1200 ms.

13. The welding process according claim 7, wherein the incremental time frame has a duration of at least 800 ms and at most 1200 ms.

10. A welding device for welding aluminum, comprising:

a welding control; and

at least one force sensor configured to measure a force between two welding electrodes on aluminum elements to be welded and transmit the measured force to the welding control,

wherein, up to the elapse of a set welding time, the welding control is configured to (i) calculate in each case during and/or after the elapse of predeterminable incremental time frames at least one of at least one absolute value and at least one increase in the measured force and to store the at least one of the at least one absolute value and the at least one increase in the measured force, and (ii) compare the at least one of the at least one absolute value and the at least one increase in the measured force in each case with at least one of a reference value and a reference curve and to calculate a control deviation resulting from the comparison, and

wherein, after the elapse of the set welding time, the welding control is further configured to subject the welding electrodes to a current of a constant level during a welding time extension that follows the set welding time, the current of the constant value being dependent on a magnitude of the control deviation that is measured at the point in time of the elapse and/or during the set welding time.