In-process automatic recalibration

{
  "publication_number": "US10955238B1",
  "country": "US",
  "kind": "B1",
  "title": "In-process automatic recalibration",
  "abstract": "An apparatus and associated method for a frame that is configured to rotate a workpiece around an axis of rotation. The apparatus has a measurement device, and a known fixture that is supported by the frame. A processor is configured to execute stored computer instructions to initially-calibrate the measurement device to the axis of rotation, to employ the initially-calibrated measurement device to obtain an initial-calibration value of the known fixture, to store the initial-calibration value in a digital memory, to subsequently use the initially-calibrated measuring device to obtain an in-process automatic recalibration (IPAR) value of the known fixture, and to compare the IPAR value to the initial-calibration value to calculate a compensation value indicating positional error of the apparatus.",
  "claims": [
    "1. A method of using a lathe, comprising: while the lathe is in a first configuration, initially calibrating a measurement probe installed in a tool holder of the lathe to a standard of known dimensions; while the lathe remains in the first configuration, using the initially-calibrated measurement probe to take one or more initial positional measurements of a non-rotating fixture carried by the lathe; storing the initial positional measurement values in a memory; after obtaining the initial positional measurement values, using the lathe to manufacture a plurality of workpieces; and while manufacture of the plurality of workpieces is in progress, using the probe to obtain a first set of subsequent positional measurements of the same fixture, without recalibrating the probe to the standard of known dimensions; storing the first set of subsequent positional measurement values in a digital memory; while manufacture of the plurality of workpieces is in progress, repeating the step of using the probe to obtain a second set of subsequent positional measurements of the same fixture without recalibrating the probe to the standard of known dimensions; storing the second set of subsequent measurement values in a digital memory; and using the initial and subsequent positional measurement values to automatically adjust the lathe so as to compensate for any deviation from its initial configuration.",
    "2. The method of claim 1, further comprising: after manufacturing a plurality of workpieces, using the probe to measure one or more features of one of the plurality of manufactured workpieces and obtain one or more measurement values.",
    "3. The method of claim 1, further comprising: using the initial and subsequent positional measurement values to detect any trend in the positional measurements; and counteracting any decrease in workpiece quality threatened by the trend.",
    "4. The method of claim 3 in which the counteracting step comprises ceasing manufacture of workpieces.",
    "5. The method of claim 1 further comprising: determining an acceptable range of the deviation between the subsequent positional measurements and the first configuration; and using the initial and subsequent positional measurement values to determine the deviation from the initial configuration.",
    "6. The method of claim 5 further comprising: while the deviation from the initial configuration remain within the acceptable range of deviation, calculating compensation so as to counteract any decrease in workpiece quality threatened by the deviation.",
    "7. The method of claim 5 further comprising: ceasing manufacture of workpieces when the deviation from the initial configuration is no longer within the acceptable range.",
    "8. The method of claim 2 further comprising: using the initial and subsequent positional measurement values to automatically adjust workpiece measurement values obtained using the probe to compensate for the deviation from the first configuration.",
    "9. The method of claim 8 further comprising: using the adjusted workpiece measurement values to automatically adjust a tool path to compensate for the deviation from the first configuration.",
    "10. A method of operating a lathe, comprising: calibrating a measurement probe installed in a tool holder of the lathe to a standard of known dimensions, the measurement probe comprising more than one stylus; thereafter, using more than one stylus of the measurement probe to obtain initial positional measurement values of a stationary fixture carried by the lathe using the initial positional measurement values to acquire an initial probe stylus configuration; storing the initial positional measurement values in a memory; thereafter, using the lathe to manufacture a plurality of workpieces; while the step of using the lathe to manufacture the plurality of workpieces is in progress, using more than one stylus of the measurement probe to obtain first subsequent positional measurement values of the stationary fixture, without recalibrating the measurement probe to the standard of known dimensions; storing the first subsequent positional measurement values in a digital memory; while the step of using the lathe to manufacture the plurality of workpieces is in progress, using more than one stylus of the measurement probe to obtain second subsequent positional measurements of the stationary fixture; storing the second subsequent positional measurement values in a digital memory; and comparing at least one of the first subsequent positional measurement values and second subsequent positional measurement values of the fixture to the initial positional measurement values to detect a deviation from the initial probe stylus configuration; in which the measurement probe is not recalibrated between the step of obtaining the first subsequent positional measurements and the second subsequent positional measurements.",
    "11. The method of claim 10, further comprising: adjusting the more than one stylus to counteract deviation from the initial probe stylus configuration.",
    "12. The method of claim 10, further comprising: measuring a workpiece with the probe after detecting a deviation from the initial probe stylus configuration; and using the deviation from the initial configuration to adjust values obtained from measuring the workpiece.",
    "13. The method of claim 10, further comprising: ceasing manufacture of workpieces in response to the detected deviation.",
    "14. The method of claim 10, further comprising: establishing an acceptable tolerance for workpiece measurements; measuring a workpiece with the probe after detecting a deviation from the initial probe stylus configuration to determine measurement values; and adjusting a tool path in response to measurement values indicative of a workpiece outside of the acceptable tolerance.",
    "15. The method of claim 14 further comprising: after adjusting the tool path, automatically performing additional machining to the out-of-tolerance workpiece using the adjusted tool path.",
    "16. The method of claim 14 further comprising: ceasing manufacture of workpieces in response to measurement values indicative of a workpiece outside the acceptable tolerance."
  ],
  "cpc": [
    "G01B 21/045",
    "G01B 21/04",
    "G01B 21/042",
    "G01B 5/004",
    "G01B 5/008",
    "G05B 19/401",
    "G05B 2219/37008"
  ],
  "assignees": [
    "KERR MACHINE CO"
  ],
  "filing_date": "2014-03-17",
  "publication_date": "2021-03-23",
  "grant_date": "2021-03-23",
  "priority_date": "2013-03-15",
  "application_number": "US-201414216597-A",
  "family_id": "74882772",
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