Techniques for determining weld quality

{
  "publication_number": "US11167378B1",
  "country": "US",
  "kind": "B1",
  "title": "Techniques for determining weld quality",
  "abstract": "A method and/or a system estimate a quality of a weld. For example, a weld information algorithm may be generated based on, for each of a plurality of welds, at least two of a first maximum weld force parameter, a minimum weld force parameter, or a second maximum weld force parameter. The weld information algorithm may be used to estimate the weld quality of a particular weld based on weld information obtained for that weld.",
  "claims": [
    "1. A method comprising: conducting a plurality of welds; determining weld information associated with the plurality of welds, wherein for each weld of the plurality of welds the weld information comprises at least two of a first maximum weld force parameter, a minimum weld force parameter, or a second maximum weld force parameter; determining weld strength information associated with the plurality of welds; and generating a weld information algorithm based on the weld information and the weld strength information, wherein generating the weld information algorithm comprises performing a first order linear regression on the weld information and the weld strength information, wherein the weld information algorithm is of the form: A+B·(minimum weld force)+C·(first maximum weld force)+D·(second maximum weld force), where A, B, C, and D are obtained from the first order linear regression.",
    "2. The method of claim 1, wherein for each weld of the plurality of welds the weld information further comprises a weld current.",
    "3. The method of claim 1, wherein for each weld of the plurality of welds the weld information further comprises a starting weld force parameter and a post weld force parameter.",
    "4. The method of claim 1, wherein the weld information algorithm provides an indication of weld quality.",
    "5. The method of claim 1, wherein the weld information algorithm comprises a first order algorithm.",
    "6. The method of claim 1, wherein an adjusted R 2 error of the first order linear regression is less than 0.5.",
    "7. A method comprising: conducting a plurality of welds; determining weld information associated with the plurality of welds, wherein for each weld of the plurality of welds the weld information comprises at least two of a first maximum weld force parameter, a minimum weld force parameter, or a second maximum weld force parameter; determining weld strength information associated with the plurality of welds; and generating a weld information algorithm based on the weld information and the weld strength information, wherein determining the weld information comprises for each weld of the plurality of welds: applying a weld current during a weld period; acquiring the first maximum weld force parameter during the weld period; acquiring the minimum weld force parameter after acquiring the first maximum weld force parameter during the weld period; and acquiring the second maximum weld force parameter during a hold period that follows the weld period, wherein the weld current is not applied during the hold period.",
    "8. The method of claim 7, wherein determining the weld information comprises for each weld of the plurality of welds: acquiring a starting weld force parameter at a start of a weld squeeze period that precedes the weld period, wherein the weld current is not applied during the weld squeeze period; acquiring a weld current parameter commencing an end of the weld squeeze period and terminating at an end of the weld period; and acquiring a post weld force parameter at an end of the weld hold period.",
    "9. The method of claim 1, wherein determining the weld information comprises receiving weld force signals from a force sensor.",
    "10. The method of claim 9, wherein the force sensor is located in-line with at least one electrode used for the plurality of welds.",
    "11. The method of claim 9, wherein the force sensor is located between an electrode holder member for the first electrode and a force generator that is configured to apply a force to the first electrode.",
    "12. The method of claim 9, wherein the force sensor is located between a first electrode of the at least one electrode and a force generator that is configured to apply a force to the first electrode.",
    "13. The method of claim 9, wherein the force sensor comprises a load cell.",
    "14. The method of claim 9, further comprising: applying a pre-load force to the force sensor prior to application of welding pressure to the at least one electrode.",
    "15. The method of claim 1, wherein determining the weld strength information comprises testing each weld of the plurality of welds.",
    "16. The method of claim 15, wherein the testing comprises at least one of: a tensile shear test, a bond shear test, or a peel shear test.",
    "17. A method comprising: conducting a weld; determining weld information associated with the weld, wherein the weld information comprises at least two of a first maximum weld force parameter, a minimum weld force parameter, or a second maximum weld force parameter, wherein the weld information algorithm is of the form: A+B·(minimum weld force)+C·(first maximum weld force)+D·(second maximum weld force); inputting the weld information into a weld information algorithm; and obtaining an indication of weld quality associated with the weld based on the weld information algorithm.",
    "18. The method of claim 17, wherein the weld information further comprises a weld current.",
    "19. The method of claim 17, wherein the weld information further comprises a starting weld force parameter and a post weld force parameter.",
    "20. The method of claim 17, wherein the indication of weld quality comprises an estimate of at least one of: weld tensile strength, bond shear strength, or weld peel strength.",
    "21. The method of claim 17, wherein the weld information algorithm comprises a first order algorithm.",
    "22. A method comprising: conducting a weld; determining weld information associated with the weld, wherein the weld information comprises at least two of a first maximum weld force parameter, a minimum weld force parameter, or a second maximum weld force parameter; inputting the weld information into a weld information algorithm; and obtaining an indication of weld quality associated with the weld based on the weld information algorithm, wherein determining the weld information comprises: applying a weld current during a weld period; acquiring the first maximum weld force parameter during the weld period; acquiring the minimum weld force parameter after acquiring the first maximum weld force parameter during the weld period; and acquiring the second maximum weld force parameter during a hold period that follows the weld period, wherein the weld current is not applied during the hold period.",
    "23. The method of claim 22, wherein determining the weld information comprises: acquiring a starting weld force parameter at a start of a weld squeeze period that precedes the weld period, wherein the weld current is not applied during the weld squeeze period; acquiring a weld current parameter commencing an end of the weld squeeze period and terminating at an end of the weld period; and acquiring a post weld force parameter at an end of the weld hold period.",
    "24. The method of claim 17, wherein determining the weld information comprises receiving weld force signals from a force sensor.",
    "25. The method of claim 24, wherein the force sensor is located in-line with at least one electrode used for the weld.",
    "26. The method of claim 24, wherein the force sensor is located between an electrode holder member for the first electrode and a force generator that is configured to apply a force to the first electrode.",
    "27. The method of claim 24, wherein the force sensor is located between a first electrode of the at least one electrode and a force generator that is configured to apply a force to the first electrode.",
    "28. The method of claim 7, wherein the weld information algorithm provides an indication of weld quality.",
    "29. The method of claim 7, wherein: determining the weld information comprises receiving weld force signals from a force sensor; and the force sensor is located in-line with at least one electrode used for the plurality of welds.",
    "30. The method of claim 22, wherein: determining the weld information comprises receiving weld force signals from a force sensor; and the force sensor is located in-line with at least one electrode used for the plurality of welds."
  ],
  "description_excerpt": "This disclosure relates generally to the welding of two or more parts that involve a force to keep the parts together during the heating process and, more specifically but not exclusively, to determining the quality of such a weld.\n\nVarious techniques may be used to determine the quality of a weld. Examples of these techniques include destructive testing, weld strength estimation, and visual inspection.\n\nDestructive testing may involve increasing the amount of force applied to a weld (e.g., a weld on a welded part) until the weld is damaged in some way. Based on the amount of force required to damage the weld and/or the damage caused to the weld, a determination may be made as to whether the weld was sufficiently strong for the intended use of the part. For example, if the amount of force required to break the weld exceeds the amount of force expected to be imparted on the part during the intended use by a certain threshold, the welding process may be deemed sufficient. If not, the welding process may be modified and the destructive testing repeated on another part that is welded using the modified welding process.\n\nWeld strength estimation techniques may involve monitoring one or more conditions during a welding process and estimating whether the resulting weld is sufficiently strong. For example, the amount of weld current applied during the welding process and the welding time may be measured and this information may be used to estimate the quality of the weld.\n\nIn practice, the above techniques may have one or more disadvantages.",
  "cpc": [
    "B23K 31/125",
    "B23K 11/115",
    "B23K 11/255",
    "B23K 9/0953"
  ],
  "ipc": [
    "B23K 11/10",
    "B23K 11/11",
    "B23K 11/25",
    "B23K 31/12",
    "B23K 9/095"
  ],
  "inventors": [
    "David W. Steinmeier"
  ],
  "filing_date": "2020-05-01",
  "publication_date": "2021-11-09",
  "grant_date": "2021-11-09",
  "priority_date": "2020-05-01",
  "application_number": "US-202016865277-A",
  "family_id": "78467526",
  "cited_by_count": 3,
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}