United Technologies Corporation

Robert T Brown

William L Nighan

The present invention is a more efficient method for manufacturing shaped holes, which include a diffuser section and a cylindrical meter section. Unlike electro-discharge machining (EDM), which is the current method for manufacturing shaped holes, the method of the present invention laser drills the diffuser section followed by the cylindrical meter section. Laser drilling the cylindrical meter section creates the formation of re-solidified vapor in the diffuser section, which is easily milled. Recognizing that it is much easier to mill re-solidified vapor compared to the parent material, the present invention first creates the diffuser section and allows re-solidified vapor to form therein. Although the re-solidified vapor is thereafter milled, the entire process of the present invention is a more efficient method for producing shaped holes in comparison to EDM.

Method for producing shaped hole in a structure

The present invention is a method and apparatus for producing a hole in a structure utilizing both an unmodulated beam and a modulated beam. The unmodulated beam first breaks through the structure, thereby forming a guide hole, and the modulated beam then produces a reaming effect by increasing the cross section of the hole to the size of the effective diameter of the modulated beam. The modulated beam increases the cross section of the hole because the modulated beam has a higher beam intensity than the unmodulated beam for a given beam radius.

Method and apparatus for producing a laser drilled hole in a structure

The onset of electric discharge instability in rare-gas monofluoride lasers pumped by electron beam sustained electric discharges (e.g., KrF*) is delayed by employing a laser gas mixture (such as 0.95 Ar, 0.05 Kr, and 0.005 F.sub.2) which includes a small amount of a halogen compound (NF.sub.3) having a rate coefficient for electron dissociative attachment which is much larger than that for fluorine (such as 0.0005 NF.sub.3). The addition of nitrogen trifluoride to the gas mixture modifies the halogen kinetics in a manner to reduce the effect that consumption of the fluorine fuel has on the growth of secondary electrons, and therefore the occurrence of instability in the discharge. The rare-gas metastable quenching coefficient for the nitrogen trifluoride is sufficiently small (on the order of six times smaller than that of the fluorine) so that the small amount of nitrogen trifluoride utilized to stabilize the discharge exerts little or no influence on the other laser processes.

Stability enhanced rare-gas monofluoride lasers

The onset of electric discharge instability in electron beam enhanced electric discharge lasers employing halides, such as rare-gas monohalides (e.g., KrF*) and mercury vapor halide (e.g., HgBr*), is delayed by limiting the production of secondary electrons during laser pulse generation, to account for critical loss of halogen or halide fuel. Secondary electron production is controlled, in order to extend the pulse duration before the onset of discharge instability, by temporal tailoring of the primary electron concentration in the electric discharge region across the temporal expanse of possible laser action; the population of primary electrons can be temporally restrained by temporal decrease of the current density of the electron gun output, as a function, for instance, of gun driving voltage, or by temporal defocusing of the electron beam so as to provide reduced densities within the electric discharge region. Secondary electron production is also controlled by tailoring the production of rare-gas metastables. The production of metastables is controlled, in turn, by temporal tailoring of the electric field so as to provide a decreasing electric field to neutral particle density ratio across the temporal expanse of the laser pulse.

Stability enhanced halide lasers

An optically pumped laser system having a configuration capable of efficiently coupling pumping radiation with a gain medium to provide an outlet beam having a wavelength in the ultraviolet and visible spectrum is disclosed. A gain medium including halide, rare and noble gas elements is contained within a cell at total pressures from four to thirty atmospheres. The gain medium is ionized by a spark source within the cell and interacted with optical pumping radiation to provide a diffuse electrical discharge. An optical resonator having the discharge disposed therein efficiently extracts energy from the gain medium to provide an output beam having a wavelength in the visible spectrum when the total pressure of the gain medium is high, typically greater than nine atmospheres and a wavelength in the ultraviolet spectrum when the pressure is moderate, typically less than five atmospheres.

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Manchester, CT, United States of America

Robert T Brown