METHOD AND APPARATUS FOR THE QUALITY INSPECTION OF LASER WELDING
First Claim
1. An apparatus for inspecting the quality of laser welding, comprising:
- a laser welding system configured to perform a laser welding process on a laser welding part;
a quality inspection sensor configured to sense a plasma light generated from the laser welding part and then output a plasma light sensing signal; and
a quality inspection unit configured to receive the plasma light sensing signal outputted from the quality inspection sensor, convert the received plasma light sensing signal into an electrical signal, filter the converted electrical signal, and determine the quality of the laser welding based on an instantaneous variation of the plasma light as an AC component of the filtered electrical signal of the plasma light,wherein the quality inspection unit further comprises a frequency dividing and filtering/amplifying portion configured to divide the plasma light sensing signal outputted from the quality inspection sensor into a plurality of frequency bands, filter one or more of the frequency band divided signals individually, amplify one or more of the frequency band divided signals individually, synthesize the filtered and amplified signals, and output a square of an input value of the synthesized signal through a multiplication amplifier.
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Abstract
The present invention relates to a method and apparatus for inspecting the quality of laser welding by monitoring the size of a metal molten pool (i.e., weld metal) during a laser welding process. The present invention provides a method and apparatus for inspecting the quality of laser welding, in which a new type laser welding quality inspection system is implemented in which one sensor signal and one filtered electrical signal of the plasma light can be used to perform a correct welding quality inspection through the development of a filtering method of an electrical signal of the plasma light, thereby facilitating a laser welding quality management and making possible its example application to a vehicle body laser welding process.
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Citations
16 Claims
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1. An apparatus for inspecting the quality of laser welding, comprising:
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a laser welding system configured to perform a laser welding process on a laser welding part; a quality inspection sensor configured to sense a plasma light generated from the laser welding part and then output a plasma light sensing signal; and a quality inspection unit configured to receive the plasma light sensing signal outputted from the quality inspection sensor, convert the received plasma light sensing signal into an electrical signal, filter the converted electrical signal, and determine the quality of the laser welding based on an instantaneous variation of the plasma light as an AC component of the filtered electrical signal of the plasma light, wherein the quality inspection unit further comprises a frequency dividing and filtering/amplifying portion configured to divide the plasma light sensing signal outputted from the quality inspection sensor into a plurality of frequency bands, filter one or more of the frequency band divided signals individually, amplify one or more of the frequency band divided signals individually, synthesize the filtered and amplified signals, and output a square of an input value of the synthesized signal through a multiplication amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for inspecting quality of laser welding comprising:
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performing a laser welding process on a laser welding part; sensing a plasma light generated from the laser welding part using a quality inspection sensor to output a plasma light sensing signal; converting the plasma light sensing signal into an electrical signal; filtering the converted electrical signal; and determining a quality of the laser welding based on an instantaneous variation of the plasma light as an AC component of the filtered electrical signal of the plasma light, wherein the step of determining the quality of the laser welding comprises i) dividing the plasma light sensing signal into a plurality of frequency bands, ii) at least one of either filtering or amplifying the frequency band divided signals individually, iii) synthesizing the filtered and amplified signals, and iv) outputting a square of an input value of the synthesized signal through a multiplication amplifier, whereby whether the quality of the laser welding is acceptable is determined using the outputted instantaneous variation of the plasma light. - View Dependent Claims (11, 12, 13, 14)
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15. A method, comprising:
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sensing a plasma light generated from a laser welding process as a plasma light sensing signal; determining an instantaneous variation of the plasma light by; i) dividing the plasma light sensing signal into a plurality of frequency bands, ii) at least one of either filtering or amplifying the frequency band divided signals individually, iii) synthesizing the filtered and amplified signals, and iv) outputting a square of an input value of the synthesized signal through a multiplication amplifier as the instantaneous variation of the plasma light; and determining quality of the laser welding process based on the instantaneous variation of the plasma light.
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16. A tangible, non-transitory computer-readable media comprising software, the software when executed by a processor operable to:
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sense a plasma light generated from a laser welding process as a plasma light sensing signal; determine an instantaneous variation of the plasma light by; v) dividing the plasma light sensing signal into a plurality of frequency bands, vi) at least one of either filtering or amplifying the frequency band divided signals individually, vii) synthesizing the filtered and amplified signals, and viii) outputting a square of an input value of the synthesized signal through a multiplication amplifier as the instantaneous variation of the plasma light; and determine quality of the laser welding process based on the instantaneous variation of the plasma light.
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Specification