Abstract: A method of forming cooling holes in a gas turbine engine component. The method includes the steps of forming a hole in the component extending between a first surface of the component and a second surface of the component opposite the first surface and supplying pressurized air to the hole from the second surface of the component. The method also includes the step of sensing a parameter representative of air flow through the hole. Further, the method includes enlarging the hole until the sensed parameter represents a preselected air flow rate through the hole.

Abstract: The present invention provides a metallic article with at least one laser shock peened surface on at least a portion of the article and a plurality of volumetrically spaced apart laser shock peened protrusions extending into the article from said laser shock peened surface wherein the protrusions have deep compressive residual stresses imparted by laser shock peening (LSP). The invention may be further characterized by spaced apart circular laser beam spots on the surface from which the laser shock peened protrusions extend into the article such that the spots do not overlap.

Abstract: A method for quality assurance of a laser process and, more particularly, a laser shock peening process that uses a ballistic momentum apparatus for maintaining quality control of a laser shock peening process that uses a laser includes a movable target mass having a laser target face and confined to freely move in one direction. An indicating means indicates a maximum distance traversed by the target mass during a recoil from firing of the laser on the target face. An ablative coating is preferably applied on at least a portion of the face and preferably a transparent confinement medium, such as a flow of water, is applied over the ablative coating.

Abstract: A method for quality assurance of a laser shock peening process uses interferometry to form a fringe image from first and second interferograms of unstressed and stressed laser shock peened patches respectively of a workpiece. The fringe image may then be compared to a predetermined correlation of fringe images for indicating quality assurance. Stressing the laser shock peened patch may include loading the production and test workpieces during the production of the first and second images by interferometry while the production and test workpieces are fixtured. The loading may be done by heating, twisting, or bending of at least a portion of the production and test workpieces. The comparing of the production images of fringes may include comparing fringe characteristics of the laser shock peened patches on the production workpieces laser against fringe characteristics of the predetermined correlation.

Abstract: A method of laser shock peening a hard metallic article by firing a laser beam on different points of a laser shock peened surface of at least a portion of the article using a laser beam with sufficient power to vaporize material on the surface around laser beam spots formed by the laser beam at the points on the surface, flowing a curtain of water over the surface upon which the laser beam is firing, and firing the laser beam so as to form a plurality of volumetrically spaced apart laser shock peened protrusions extending into the article from the spots such that the protrusions have deep compressive residual stresses imparted by laser the laser beam. The surface may first be coated with an ablative material which the laser beam vaporizes and the method may be an on the fly method of laser shock peening which further includes continuously moving the article while continuously firing a stationary laser beam which repeatably pulses between relatively constant periods.

Abstract: A method of laser shock peening a gas turbine engine object continuously firing a stationary laser beam, which repeatably pulses between relatively constant periods, on a portion of the object with a low power laser beam, on the order of 3-10 joules, to vaporize material on the surface of a portion of a part made of a strong hard metal, such as a titanium alloy. Laser pulses around small laser beam spots, on the order of 1 mm in diameter, are used to vaporize material on the surface of the portion of the object with the pulses around laser beam spots formed by the laser beam on the surface and form a region having deep compressive residual stresses extending into the object from the laser shock peened surface. Flowing a curtain of water over the surface upon which the laser beam is firing while preferably moving the object until the laser shock peened surface is completely covered by laser beam spots at least once.

Abstract: A method for forming a slot in a metal component having first and second opposite surfaces utilizes a first laser beam having a pulse rate and power to vaporize the metal. The laser beam is traversed across the first surface at a feed rate so that each beam pulse vaporizes the component metal at a spot. The laser beam pulse rate and feed rate are effective so that successive spots do not substantially overlap each other. The laser beam is traversed in repeated steps in a series of passes so that the spots collectively form a continuous slot to a depth below the first surface. In a subsequent step, a second laser beam is positioned in the slot to drill a hole through a base of the slot, with the second laser beam being repositioned to drill a plurality of the through holes spaced apart from each other along the length of the slot.

Abstract: A method for forming an aperture in a component wall made of metal, the aperture having a diffuser which opens up and outward from a bottom of the diffuser to a first surface of the wall, the method includes the following steps: A) laser machining the wall with a laser which produces a laser beam having a pulse rate and power sufficient to vaporize the metal; B) firing and traversing the laser beam, preferably at an acute angle, across the surface to a predetermined first edge of the diffuser in a single pass starting at a centerline of the diffuser; and C) traversing the laser beam at an increasing rate of speed during the pass so that each beam pulse vaporizes the metal at a laser spot such that successive laser spots substantially overlap each other in decreasing amounts and the pulses nibble out the metal to form a continuous trench below the surface.

Abstract: Apparatus and method for performing material processing, such as drilling or welding, with a high intensity laser beam operating in the infrared spectrum, using a reflective holographic optical element (HOE) the surface of which is prepared to contain an image of the object under processing and energy intensity information, the object can be located in or out of line-of-sight with respect to the emitted laser beam.

Abstract: This invention relates to face-pumped slab lasers of the type that have laser head assemblies constructed of individual components, which are rigidly attached together, in order to form an integral structure. Such structures of this type, generally, allow a face-pumped slab laser component to be assembled and disassembled easily and quickly.

Abstract: A method for making a gas turbine engine component includes the steps of: providing an unfinished gas turbine engine component; directing a laser beam on a selected surface portion of the engine component to prepare the selected surface portion before at least one of a subsequent coating and bonding step; and depositing at least one layer of an abradable material, a subassembly of the component or a thermal barrier coating on the selected surface portion.

Abstract: A laser apparatus is disclosed which is capable of protecting the laser slab or rod crystal within the laser from damage due to overheating when the laser malfunctions in a manner such that laser output ceases while optical pumping of the laser crystal continues. The laser apparatus includes a laser crystal situated within a laser cavity. The apparatus also includes an excitation lamp for pumping the crystal to generate a laser beam to project along a desired main path. A first sensor senses the cessation of the projection of the laser beam along the desired main path and a second sensor senses the continuing excitation of the excitation lamp. The apparatus further includes a extinguishing circuit for extinguishing the excitation lamp a predetermined amount of time after the cessation of the laser beam such that damage to the laser apparatus due to overheating is avoided.

Abstract: A method for making a gas turbine engine component includes the steps of: providing an unfinished gas turbine engine component; directing a laser beam on a selected surface portion of the engine component to prepare the selected surface portion before at least one of a subsequent coating and bonding step; and depositing at least one layer of an abradable material, a subassembly of the component or a thermal barrier coating on the selected surface portion.

Abstract: A system for detecting energy leakage from an optical fiber transmitting high power laser beams. A second optical fiber is placed together with the laser power transmitting fiber into a jacketing tube or conduit. The second fiber is connected at one end to a light source and at the other end to a photosensitive diode. Leakage of laser energy from the power transmitting fiber will cause a failure of the second optical fiber, reducing or terminating the transmission of light to the photosensitive diode. Energy leakage from the laser power transmitting fiber can therefore be detected by monitoring the output of the photosensitive diode.