A single pass actuator (70, 200), such as a deformable mirror (70), quickly changes, preferably in less than 1 ms, the focus and hence the spot size of ultraviolet or visible wavelength laser pulses to change the fluence of the laser output (66) at the workpiece surface between at least two different fluence levels to facilitate processing top metallic layers (264) at higher fluences and underlying dielectric layers (266) at lower fluences to protect bottom metallic layers (268). The focus change is accomplished without requiring Z-axis movement of the laser positioning system (62). In addition, the spot size can be changed advantageously during trepanning operations to decrease via taper, reduce lip formation, increase throughput, and/or minimize damage.

Laser system and method for single press micromachining of multilayer workpieces

A laser cutting apparatus for cutting successively different configurations on a moving feed stock (22) includes a laser (40) generating a laser beam, a scanner (42) directing the beam to the feed stock, and a control device (18) which monitors the relative speed and location of the feed stock and controls the scanner. An encoder (54) and registration mark sensor (44) provide the monitoring of the speed and position of the feed stock, respectively. The laser-cut feed stock may be provided with beveled edges via appropriate focusing of the laser beam.

Dynamic laser cutting apparatus

A high energy laser is imbedded into a highly laminar high pressure stream by pumping fluid (preferably water) into a conduit, controlling the flow of fluid by a valve in the conduit, introducing the fluid into an outlet orifice assembly with a fluid chamber and a diffuser within the fluid chamber to dampen major currents of fluid velocity. A laser beam is aligned and directed through the outlet orifice. The fluid exiting the orifice creates a laminar fluid stream about the laser. The outlet orifice can have a knife edged orifice.

Water laser machine tool

A method of determining optimum heating conditions for applying a pulse laser point heat source onto a strip of a brittle material at its position in the vicinity of a tip of a crack of the strip for cleaving the strip by a thermal stress, wherein at least one of a non-dimensional pulse time of the pulse laser point heat source, a non-dimensional distance of the pulse laser point heat source from the tip of the crack, and a non-dimensional heating area is decided so that a ratio of non-dimensional stress intensity factor to temperature takes just or approximately a maximum value.

Method of cleaving a brittle material using a point heat source for providing a thermal stress

The method and apparatus for cutting through flat workpieces made of glass can cut through workpieces with greater thickness, e.g. glass panes with a thickness greater than 0.2 mm, than possible up to now with a comparable known method, without micro-fractures, glass fragments or splitter. In the method of the invention a heat radiation spot symmetric to the cutting line is produced on the workpiece. This heat radiation spot has edge portions with elevated radiation intensity and is moved along the cutting line and/or the workpiece and the heated section of the cutting line is subsequently cooled. A scanner motion produces the heat radiation spot so that edge portions of elevated radiation intensity coincide with a V- or U-shaped curve, which is open at the leading end of the heat radiation spot. The peak portion of the V- or U-shaped curve on the cutting line is at a temperature maximum that is under the melting point of the workpiece material. A controller of the scanning motion controls the scanner in circular cutting and freeform cutting so that a curved V- or U-shaped intensity distribution which fits the curved cutting path arises.

Method and apparatus for cutting through a flat workpiece made of brittle material, especially glass.

A machining head of a laser machining apparatus comprises a main assist gas nozzle at the center portion of the machining head for supplying a main assist gas and one or more annular sub assist gas nozzles surrounding the main assist gas nozzle, whose jet outlet of the innermost diameter is larger or equal to the jet outlet of main assist gas. The jet outlet of the main assist gas nozzle is positioned at upstream of said jet outlets of the respective sub assist gas nozzle. According to the above construction, the jet gas pressure and the jet gas velocity vary continuously at the assist gas jet outlet and the jet gas pressure and flow velocity fluctuation of the main assist gas are increased.

Machining head and laser machining apparatus

In the present invention, a laser beam with a prespecified oscillation frequency is divided into the arbitrary number of pulses to be irradiated to all holes in an area, and this step is repeated until the irradiation reaches a desired number of pulses, whereby an interactive time can be decided according to the number of divided pulses and a cooling period of time can be obtained, and also the number of pulses per one division is set to be a plurality of pulses, which allows an etching rate to be increased, so that the number of pulses required for machining can be reduced as compared to a case where a laser is irradiated to all the holes pulse by pulse.

Laser machining method

A laser cutting method with which cutting faults at the time of cutting condition changing are substantially eliminated. Impingement of the laser beam on the workpiece is stopped when the laser beam reaches a position along the path where the first cutting conditions are to be changed to second cutting conditions. The laser beam is then retracted along the path a predetermined distance from the position where the first cutting conditions are to be switched to the second cutting conditions. After a delay time, the laser beam is again moved along the predetermined path to cut the workpiece under the second cutting conditions. The retraction distance is set in accordance with the thickness of the workpiece. Also, an assist gas may be sprayed on the workpiece in the vicinity of the cutting path while impingement of the beam is stopped.

Laser cutting method eliminating defects in regions where cutting conditions are changed

A laser welding method which provides improved welding quality, allowing excellent products to be produced. The mixture of inactive gas or nitrogen gas and 5% to 35% of oxygen gas in terms of volume ratio and that of inactive gas or nitrogen gas and not less than 25% of dried air in terms of volume ratio are employed as an assist gas in the lap and butt weldings and filler wire-inserted welding of metal materials filmed with low melting point substance.

Method and apparatus for laser welding with an assist gas including dried air and the assist gas composition

A laser-beam operated machining apparatus capable of performing machining operations on a high-reflectivity material such as aluminum or copper. A nozzle is provided for applying a focused laser beam together with an assist gas to a surface of a workpiece to be machined. An annular electrode is provided on the end of the nozzle confronting the workpiece with the electrode being coaxial with the laser beam. An arc discharge is created between the annular electrode and the workpiece by applying a voltage between the annular electrode and the workpiece so as to cause an arc discharge therebetween.

Masaru Kanaoka

Papers

Machining head and laser machining apparatus

Laser machining method

Laser cutting method eliminating defects in regions where cutting conditions are changed

Method and apparatus for laser welding with an assist gas including dried air and the assist gas composition

Laser-beam operated machining apparatus