Abstract: Fiber optic laser apparatus for spot welding, brazing, or soldering comprises an optical fiber for transmitting a laser beam to a workpiece, and a tool disposed at an output end of the optical fiber for mechanically engaging and applying pressure to the workpiece. The output end of the optical fiber is supported within a longitudinal bore of the tool with the tip of the fiber closely adjacent to an opening in a workpiece-engaging end of the tool. The diverging laser beam from the end of the optical fiber projects a spot onto the workpiece through the opening with sufficient power to cause melting without the necessity for a lens system for focusing of the laser beam.

Abstract: A solder bridge between leads of a microelectronic circuit is removed by projecting a laser beam onto the solder bridge with sufficient power to cause the solder forming the bridge to melt and to flow onto a wicking tool placed into contact with the solder bridge. The wicking tool is removed during the heating to remove the solder and debridge the leads. Microelectronic leads having a width of the order of 4 mils and a pitch of the order of 8 mils may be debridged easily using the invention.

Abstract: Mechanical apparatus and method for positioning an optical fiber for injection with a laser beam is disclosed. The apparatus comprises a mechanical seat which is positioned to abut a first optical fiber which has been aligned by an optical alignment technique. Upon the need to replace the first fiber, the apparatus enables positioning of the mechanical seat at the same location so that a second fiber can be aligned in the same position as the first fiber without the need to employ an optical alignment technique.

Abstract: A system for directing successive beam pulses of a pulsed laser into different optical fibers, for transmission therethrough, is disclosed. The system comprises at least one lens, a plurality of optical fibers with the tips thereof positioned proximate a focal point of the lens, and at least one galvanometer driven mirror for directing a laser beam through the lens for focusing separately onto each fiber tip. The galvanometer, driven by computer generated position addresses, moves the mirror, between laser pulses, to predetermined positions each effective to direct the laser beam, through the lens, into one of the fiber tips for transmission via the fiber to a remote workstation location. In a first illustrated embodiment, a single mirror is mounted to direct the laser beam into fiber tips positioned substantially in the same plane and proximate the focal points of eight lenses.

Abstract: Laser materials processing apparatus for performing processing with a fiber optic transmitted beam is disclosed. A fiber injecting lens is selected to have a focal length of sufficient length to enable the use, for materials processing, of the diverging beam emitted at an output end of the fiber without the need for a beam focusing lens type output coupler.

Abstract: An optical fiber holder includes a pair of flat, adjacent surfaces. Each of the surfaces includes a straight groove, the grooves opposing so as to form a passage shaped to engage an optical fiber in a snug fit. Means are provided for fastening the two surfaces together. The optical fiber holder is preferably constructed of material transparent to a laser beam at a predetermined wavelength, thereby making the optical fiber holder particularly adapted for use with a laser device generating such a laser beam.

Abstract: A system for injecting successive beam pulses of a pulsed power laser into optical fibers, for transmission therethrough, is disclosed. The system comprises four lens, four fiber groups with the tips thereof respectively proximate the focal points of the lenses, two galvanometer driven mirrors for directing the laser beam through one of the lenses for focusing onto a selected fiber tip, and control means to drive the galvanometers to reorient the two mirrors between laser beam pulses into successive pairs of predetermined positions effective to inject the successive beam pulses into selected fibers. Failure to reorient the mirrors before the succeeding beam pulse arrives results in laser shutdown. Means are provided for detecting a malfunction of the mirrors, fracture of a lens or a missed fiber injection and, in either case, shutting down the laser.

Abstract: A low-divergence 1.06 micrometer wavelength beam from a total-internal-reflection, face-pumped laser (TIR-FPL) is focused onto the end of a quartz optical fiber to a spot having a size smaller than the fiber diameter and with a beam cone angle less than twice the numerical aperture of the fiber. The fiber transmits the energy to emerge at the other end where it is collimated and focused onto material to be processed. A laser average output power level greater than 400 watts can be transmitted through an optical fiber having a diameter less than 600 micrometers.

Abstract: Pulse laser energy in the near infrared and visible spectrum is passed through a single fiber optic at power levels required for material and metal processing. A neodymium-YAG laser used in pulsed mode is coupled to the end of a quartz fiber optic which transmits peak powers in the kilowatt range. In order to transmit higher amounts of average power, a prepared fiber end allows beam coupling through core-air and core-cladding zones. The beam at the output of the fiber optic is focused to achieve power densities capable of cutting, drilling, and welding of metals etc. The main advantage is greater flexibility of laser beam manipulation.

Abstract: Laser processes such as cutting, drilling, and welding metals and other materials are performed manually with a hand held fiber optic laser tool. A near infrared or visible wavelength pulsed laser beam is coupled to the tool by a single clad quartz fiber whose ends are prepared to reduce losses and which transmits laser energy with peak powers in the kilowatt range to the output end. The hand held laser tool is comprised of focusing optics for the laser beam, an inert gas supply for welding cover gas, and an oxygen supply for gas assist cutting.

Abstract: A high pressure metal (sodium) vapor lamp comprises an outer vitreous envelope and an inner ceramic arc tube supported within it. The arc tube contains vaporizable metal in excess of the quantity vaporized in operation and the heat balance determines a cold spot whereat excess metal collects. The temperature of the cold spot determines the vapor pressure and the voltage drop across the lamp which must lie between specified limits. A thermal link is provided to a metal member such as the exhaust tube, the heat loss from which influences significantly the temperature of the cold spot. In completed lamps measuring too low in voltage, such thermal link may be partly severed without breaking open the outer envelope in order to raise the voltage. One convenient way utilizes an auxiliary wire which is cut by aiming a laser beam at it. Another convenient way to reduce the conductive cross section of the thermal link is to use a laser to drill one or more holes through a metallic member comprising the thermal link.

Abstract: An improved laser-assisted machining process has special application to difficult-to-machine materials such as the titanium alloys and high temperature superalloys. A layer of material to be removed by a cutting tool is made weaker by drilling a series of holes using a pulse laser beam ahead of the cutting process so that the tool removes the rest of the weaker material with relative ease. There is a decrease of cutting forces, breakage of the chip to a manageable size, and reduced tool wear.

Abstract: A rapid method of cutting thin amorphous metal sheet material is to use a focused heat source such as a laser beam or electron beam to heat local regions of the material above the crystallization temperature and form brittle crystalline lines along which the material fractures when it is mechanically deformed as by passage through a set of rollers. The material is not melted and does not form burrs. A higher packing factor is possible for motor and transformer laminations.

Abstract: Residual stress measurements are made using a strain gage and stress relief achieved by local melting of a region of the object being tested by a laser beam or other finely directed heat source. Surface strain is measured dynamically before the heat of the molten region diffuses under the gage and results in thermal stress. The method is semi-nondestructive because the molten region recasts with little loss of material, is rapid, and can be utilized on difficult geometries such as the interior surface of reactor pipe.

Abstract: Copper and aluminum conductors are butt welded or corner welded by a two-part process involving heating and melting the Cu-Al interface with energy from a pulse laser and simultaneously generating a contact pressure. The laser wavelength is 1.06 micrometers or less and a single 8 millisecond pulse is used. Brittle intermetallics are found in the flash but the narrow fusion zone in the weld is substantially free of intermetallics. High conductivity aluminum is successfully welded to electrolytic tough pitch (ETP) copper wire.