Method and system for control of a material removal process using spectral emission discrimination

A method for removing material from a structure, comprising the steps of:

• (1) generating a pulsed light beam having a pulse period;
• (2) irradiating the surface material of a structure with said pulsed light beam at an intensity sufficient to ablate said surface material and to cause said ablating surface material to generate spectral emission signals having intensities;
• (3) scanning the structure with the light beam;
• (4) monitoring said spectral emissions to detect a selected one of said spectral emission signals having a selected wavelength and generating electronic output signals representative of the intensity of said selected one of said spectral emission signals in response to detecting said selected one of said spectral emissions signals;
• (5) determining an updated scan speed functionally related to said electronic output signals generated during a predetermined interval of said pulse period of said light beam;
• and
• (6) directing said scan speed to be equal to said updated scan speed.

A method for removing material from a structure, comprising the steps of:

• (1) generating a pulsed and coherent light beam having a broadband output and a pulse period;
• (2) irradiating the surface material of a structure at a target area with said pulsed light beam at an intensity sufficient to ablate said surface material;
• (3) irradiating said target area of said structure with a laser pulse having an intensity sufficient to ablate said surface material so as to cause said surface material to generate spectral emission signals having intensities when a difference between said spectral characteristics of said light beam and said spectral emission signals is substantially at a maximum;
• (4) scanning said structure with said light beam at a scan speed;
• (5) monitoring said spectral emission signals to detect a selected one of said spectral emission signals having a selected wavelength, and generating electronic output signals representative of the intensity of said selected one of said spectral emission signals in response to detecting said selected one of said spectral emission signals;
• (6) determining an updated scan speed functionally related to said electronic output signals generated during a predetermined interval of said pulse period;
• and
• (7) directing said scan speed to be equal to said updated scan speed.

A system for removing material from a structure, comprising:

• an optical energy source for generating a pulsed light beam for irradiating the surface material of a structure with said a pulsed light beam having an intensity sufficient to ablate said surface material and to cause said ablated surface material to generate spectral emission signals having intensities;
• scanning means supporting said optical energy source for scanning said structure with said light beam;
• photodetecting means for monitoring said spectral emissions to detect a selected one of said spectral emission signals having a selected wavelength and for generating an electronic output signal functionally related to the intensity of said selected one of said spectral emission signals in response to detecting said selected one of said spectral emission signals;
• and
• a data processor operably coupled to said photodetecting means and said scanning means for determining a scan speed functionally related to said electronic output signal and for directing said scanning means to transport said optical energy source at said scan speed so that said light beam scans said structure at said scan speed.

A system for removing material from a structure, comprising:

• an optical energy source generating a pulsed, incoherent light beam for irradiating the surface material of a structure with said light beam having an intensity sufficient to ablate said surface material and to cause said ablated surface material to generate spectral emission signals having intensities, where said light beam has a pulse period;
• scanning means for scanning said structure with said light beam;
• photodetecting means for monitoring said spectral emissions to detect the intensity of a selected one of said spectral emission signals having a selected wavelength and generating electronic output signals representative of said selected one of said spectral emission signals in response to detecting said selected one of said spectral emissions signals;
• and
• a data processor operably coupled to said photodetecting means and to said scanning means for determining a scan speed functionally related to said electronic output signals generated during a predetermined interval of said pulse period.

A system for removing material from a structure, comprising:

• an optical energy source generating a pulsed, incoherent light beam having a pulse period for irradiating the surface material of a structure at a target area with said light beam having an intensity sufficient to ablate said surface material;
• a laser generating a pulsed, coherent laser beam for irradiating said target area of said structure with said laser beam having an intensity sufficient to ablate said surface material so as to cause said surface material to generate spectral emission signals having intensities when said amplitude of said waveform of said light beam is approximately at said minimum amplitude;
• scanning means supporting said incoherent optical energy means and said laser for scanning said structure with said incoherent light and laser beams;
• photodetecting means mounted to said scanning means for monitoring said spectral emissions to detect a selected one of said spectral emission signals having a selected wavelength and generating an electronic output signal representative of the intensity of said selected one of said spectral emission signals in response to detecting said selected one of said spectral emission signals generated by said laser pulse;
• a data processor operably coupled to said monitoring means and said scanning means for determining a scan speed functionally related to said electronic output signal generated during a predetermined interval of said pulse period.