Resistance spot weld head with integrated accelerometer

Patent metadata

Field	Value
Publication number	US-11224932-B2
Application number	US-201815951889-A
Country	US
Kind code	B2
Filing date	Apr 12, 2018
Priority date	Apr 12, 2018
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

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.

First claim

The invention claimed is:

1. An apparatus comprising:
a resistance spot weld (RSW) head that defines a parallel gap weld (PGW) configuration and an opposed welding configuration, the RSW head comprising:
one or more processing circuits include one or more microprocessors;
a first electrode and a second electrode, wherein the first electrode and the second electrode are in contact with a first set of components on one side, wherein the first electrode and the second electrode are configured to execute a PGW on the first set of components while the first set of components are secured to a base on an opposed side with the first electrode and the second electrode when the RSW head is in the PGW configuration, wherein, alternatively, the first electrode is configured to execute an opposed RSW (opposed weld) on a second set of components with a third electrode embedded within the base, wherein the second set of components are secured between the first electrode and the third electrode 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 execute instructions for identifying weld defects stored in a memory so as the one or more processing circuits are configured to:
determine that the PGW set of acceleration data indicates a first weld 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 weld 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 weld defect and the second weld defect, wherein the first portion 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 weld defect and the second weld 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 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 weld 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 weld 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 base on a fourth set of components secured to the 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 weld 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 weld 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 base and wherein the RSW head is configured to execute the opposed weld by moving the first electrode toward the 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 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 weld 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 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 weld 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 weld defect based on the one or more processing circuits determining that the PGW set of acceleration data indicates the first weld defect; and
the one or mo

Assignees

• Medtronic Inc

Inventors

• Schultz Steven J
• Gronneberg-Schnoes Nicholas A
• Hartung John E
• Yakovlev Vadim A
• Nikrin Peter
• Tuominen Scott N
• Westenberg Enrico
• Weiss Jeffrey P

Classifications

• B23K31/125

  Weld quality monitoring · CPC title

• B23K11/25 Primary

  Monitoring devices · CPC title

• B23K9/22

  Percussion welding · CPC title

• B23K11/115

  by means of two electrodes placed opposite one another on both sides of the welded parts · CPC title

• G01P15/122

  by metal resistance strain gauges, e.g. wire resistance strain gauges · CPC title