Maxwell Laboratories, Inc.

Mcdonnell Douglas Corporation

Cold Jet, Inc.

Richard R Hamm

Michael C Cates

Wayne N Schmitz

Michael W Lewis

John D Hoogerwerf

Cyril J Silberman

Alan C Kolb

Edmond Y Chu

John D Hoogerwerl

Leonard W Braverman

A system is provided for removing material from a structure having at least one layer of the material formed on a substrate. The system includes a radiant energy source, such as a flashlamp, with an actively cooled reflector for irradiating a target area of a structure with radiant energy, preferably sufficiently intense in at least the visible and ultraviolet, to break or weaken chemical bonds in the material, and an abrasive blaster for impinging the material after irradiation with a cool particle stream, preferably including of CO.sub.2 particles, to remove the irradiated material and cool the substrate. The system may also include light sensors used in a feedback loop to control the removal process by varying the speed at which the radiant energy source is moved along the structure, the repetition rate of the source, the intensity of the source, the pulse width of the source and/or the distance between the source and the structure.

System for removing a coating from a substrate

An improved system and method are provided for removing material coatings or contaminants such as paints from a structure. The system and method include a radiant energy source, such as a flashlamp, for irradiating the target area of the structure with the radiant energy sufficient to initiate the pyrolysis and/or ablation of the coating or contaminant and a low temperature carbon dioxide stream which is directed at the target area to disperse the material from the structure, clean the exposed surface and cool the underlying substrate. The low temperature carbon dioxide stream is formed from a liquid carbon dioxide from a liquid carbon dioxide source which undergoes phase transition to yield a predetermined amount of low temperature carbon dioxide gas and carbon dioxide snow. The system and method eliminate the need for a carbon dioxide pelletizer, a carbon dioxide pellet transport hopper, and a compressed carrier gas which are used in related systems.

Method and apparatus for removing contaminants and coatings from a

A method and system for improving the capability of a surface of an organic structure to bond with another material includes irradiating a target area of the surface of a structure with pulsed, incoherent optical energy having wavelength components which range from 160-5000 nanometers at an intensity sufficient to photodecompose any adventitious organic substances on the surface and to photodecompose a thin layer of molecular bonds forming the surface of the structure; and exposing the target area of the surface to ionized gas that chemically reacts with the target area of the surface to increase the surface free energy of the surface. A similar method and system may also be employed to improve the bondability of a metallic surface by first precleaning the metallic surface to dislodge any inorganic substances from the surface; and second irradiating a target area of the surface with pulsed, incoherent optical energy having wavelength components in the range of 160-5000 nanometers at an intensity sufficient to photodecompose any organic substances present on the surface.

Method for using pulsed optical energy to increase the bondability of a

A method is provided for removing material from a structure having at least one layer of material formed on a substrate. The method includes the steps of irradiating a target area of a structure with radiant energy sufficient to break or weaken chemical bonds in the material, and impinging the target area with a particle stream to remove the pyrolyzed material from the structure. The method may be implemented by a system comprising a housing having a window; a radiant energy source mounted in the housing for irradiating the target area of the structure with the radiant energy; and a nozzle mounted to the exterior of the housing for directing the stream of particles at the target area.

Method and system for removing a coating from a substrate using radiant

Pulsed light sources, such as a flashlamp or laser, remove coatings from substrates via the ablation method. A photodetector circuit, sensing reflected light from the surface being ablated, provides a feedback signal that indicates the reflected color intensity of the surface being ablated. The boundary between the coatings or substrate surfaces is distinguished by a change in color intensity between an upper coating and an undercoating, e.g., between a topcoat of paint and a primer coat of paint, or between a coating and the substrate surface itself. The color intensity determination thus provides a measure relative to when one coating has been removed and another coating remains. The photodetector circuit is also useful for providing feedback information relative to the quality of a stripped work surface for quality control or other purposes.

Method and system for selective removal of material coating from a

A method for removing material from a structure, comprising the steps of: (1) generating a light beam; (2) irradiating the surface material of a structure with the light beam having an intensity sufficient to ablate the surface material and to cause the surface material to generate spectral emission signals having intensities; (3) scanning the structure with the light beam at a scan speed; (4) monitoring the spectral emissions to detect a selected one of the spectral emission signals having a selected wavelength and generating an electronic output signal representative of the intensity of a selected one of the spectral emission signals in response to detecting the selected one of the spectral emission signals; (5) determining an updated scan speed functionally related to the electronic output signal; and (6) directing the scan speed to be equal to the updated scan speed. A second embodiment determines the updated scan speed based on the intensity of spectral emission signals detected during predetermined intervals while the structure is illuminated by the light source. A third embodiment determines an updated scan speed based on the intensity of spectral emission signals resulting from a laser pulse irradiating the structure when the output of the light beam is approximately at a minimum.

Method and system for control of a material removal process using

The present invention provides an automated system and method for removing one or more layers of a material from a substrate. The system and method include irradiating a structure comprising at least one layer of material formed on a substrate with a light beam having an intensity sufficient to ablate the materials in order to expose selected regions of the substrate, where the ablated material generates photoacoustic signature signals; scanning the structure with the light beam along a predetermined path at a scan speed; detecting the photoacoustic signature signals; determining an updated scan speed functionally related to the detected photoacoustic signals; and directing the scan speed to be equal to the updated scan speed. Another embodiment exposes a selected layer of a multilayered structure in a process which includes irradiating the surface of multilayered structure at a first location with a light beam having sufficient intensity to ablate the irradiated layer and generate photoacoustic pressure wave signals; detecting the photoacoustic pressure wave signals generated at the irradiated surface; comparing representations of the photoacoustic pressure wave signals with a reference value corresponding to a photoacoustic signature signal of a layer of the structure selected to be exposed; and directing the light source to scan the surface of the structure at a scan speed functionally related to the difference between the photoacoustic pressure wave signals and the reference value.

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San Diego, CA, United States of America

Richard R Hamm