Abstract: An inexpensive pulse laser device that outputs a laser pulse capable of welding a transparent member is provided. There is provided a pulse laser device including: a laser light source 1 that outputs a repeated pulse laser; a demultiplexer 2 that demultiplexes the pulse laser output from the laser light source 1 into two pulse lasers; first pulse train generation means 3 that generates a first pulse train by changing at least a peak power and/or a pulse width of one of the two pulse lasers demultiplexed by the demultiplexer 2; and a multiplexer 4 that multiplexes the other of the two pulse lasers demultiplexed by the demultiplexer 2 and the first pulse train generated by the first pulse train generation means 3, in which a pulse laser in which a low-peak power pulse laser is superimposed on a high-peak power ultra-short pulse laser is output.

Abstract: The present invention provides a laser welding method for steel sheets. The laser welding method includes irradiating a low heat input laser beam to a weld zone with a uniform welding pattern of a zigzag shape, with a constant pitch, and with a constant welding speed, so that autogenous welding may be achieved without a feed wire, such that cost of material may be reduced and joinability and performance may be improved.

Abstract: A laser beam welding head for the welding of metal parts and method of use include at least one beam path for a welding beam and means for the optical acquisition of the position of the welding seam at a first measuring position, wherein the means for the optical acquisition of the position of the welding seam allow arrangement of the first measuring position in the welding direction running ahead of the welding position of the welding beam, and, at least as a function of a lateral deviation of the welding seam from a reference position, generate a correction signal for the correction of the welding position of the welding beam, as well as a corresponding use of the laser beam welding head.

Abstract: A laser arc hybrid welding head and method which can form satisfactory beads at high speed are provided. A laser arc hybrid welding head (1) for welding a base material (W), which comprises aluminum steel sheets, by performing laser light irradiation and arc discharge, thereby combining laser welding and arc welding, splits inputted laser light (L0) into two beams, i.e., split laser light beams (L2a and L2b), then irradiates the base material (W) with the split laser light beams (L2a, L2b) while focusing these beams (L2a, L2b) on the base material (W), and also performs coaxial welding by generating an arc (A) from an arc electrode (20) disposed coaxially with the optical axis of the split laser light beams (L2a, L2b). Further, the transfer mode of a welding droplet from the arc electrode (20) is rendered spray transfer.

Abstract: A technique for laser welding an anode lead to an anode termination of an electrolytic capacitor is provided. The technique involves directing a laser beam through one or more refraction elements before it contacts the lead and anode termination. By selectively controlling the index of refraction and thickness of the refraction element, the angle at which the refraction element is positioned relative to the laser beam, etc., the laser beam may be directed to a precise weld location without substantially contacting and damaging other parts of the capacitor.

Abstract: An optical measuring device for monitoring a joint seam, joining head and laser welding head. The optical measuring device monitors a joining region in a workpiece and has at least one light-section device with a first light source for casting a light fan in the direction of the workpiece to be joined, making a triangulation light line within the joining region which intersects a joint seam. An illumination device with a second light source homogeneously illuminates the joining region. A first optical sensor with a first observation beam path for spatially resolved imaging of the triangulation light line is projected onto the joint seam. A second optical sensor with a second observation beam path for spatially resolved imaging of the joint seam is coaxially coupled with the first observation beam path. The readout rate of the first and second optical sensors is >1 kHz and <500 Hz, respectively.

Abstract: Weld seams that vary in height along the lengths of a pair of workpieces are produced using at least one laser weld head mounted for vertical and rotary movements to accommodate differences in the vertical heights and contours of seam lines along which the weld seams are to be formed.

Abstract: A system for welding a tub of a railroad tank car includes a manipulator boom adapted to move with respect to the interior surface of the tank shell. A hybrid laser arc welding head mounted to the manipulator. A supplemental gas metal arc welding head includes dual wires of welding material and is mounted to the manipulator adjacent to the hybrid laser arc welding head. An inductive heating coil is mounted adjacent to the supplemental gas metal arc welding head. The hybrid laser arc welding head welds a seam of the railroad tank car shell with the supplemental gas metal arc welding head following to generally complete filling of a resulting weld joint with welding metal. The supplemental gas metal arc welding head is followed with the inductive heating coil to provide heat to normalize the resulting weld joint.

Abstract: The repair of cracks according to the state of the art comprises the fact that defects located on the inside must be worked outward in order to be able to be welded closed. The method according to the invention proposes not to work out cracks located on the inside, but to melt the crack located on the inside utilizing a flux agent.

Abstract: A laser welding apparatus includes laser generator, arc generator, wire feeder, filler feeder, filler-feeding-abnormality detector, and controller. Controller stops welding immediately upon receiving a filler-feeding-abnormality signal from filler-feeding-abnormality detector. This can stop welding before the formation of a defective weld bead, and can also prevent the breakage of the welding apparatus.

Abstract: The time between illumination of adjacent zones of a workpiece edge is extended by a long cool-down period or delay, by interlacing a radiation beam scanning pattern. During the cool-down period, the beam successively scans (along the fast axis) two rows separated by about half the wafer diameter, and travels back and then forth (along the slow axis) across the distance between the two rows, while the radiation beam source continuously generates the beam.

Abstract: Methods and systems for ultrashort pulse laser processing of optically transparent materials are disclosed. At least one embodiment includes a method for welding materials with ultrashort laser pulses to create a bond through localized heating, at least one material being transparent at a laser wavelength. The ultrashort pulse duration causes nonlinear absorption of the laser radiation, and the high repetition rate of the laser causes pulse-to-pulse accumulation of heat within the materials. The laser is focused near the interface of the materials, generating sufficiently high fluence at the region to be welded. This minimizes damage to the rest of the material and enables fine weld lines. In various implementations the laser is focused near the sub-surface interface between two materials, generating high fluence at the region proximate to the laser focus with minimal modification to the surrounding region, including areas above and below the laser beam waist.

Abstract: A laser welding apparatus includes: a first optical element that coaxially emits, to a welded part, a laser beam emitted from a laser light source and an object beam having a different wavelength from the laser beam; a second optical element that causes the spot diameter of the object beam to be larger than the spot diameter of the laser beam on the welded part; an optical interferometer that emits the object beam to the first optical element, detects through the first optical element the object beam reflected on the welded part, and generates an electric signal based on the detected object beam; and a measuring unit that measures a penetration depth of the welded part based on the electric signal.

Abstract: Apparatuses for fabricating micro patterns using a laser diode array and methods for fabricating micro patterns are presented. The apparatus includes a laser diode array having at least one laser diode wherein light emitted from each laser diode is focused by a convex lens onto a second material layer attached to a first material layer. At least one driving shaft drives motion of the first and the second material layers. An adjustment means is used for adjusting the gap and pitch between adjacent laser diodes.

Abstract: A device for laser welding of a workpiece includes a laser treatment head, a receiver carrying the laser treatment head and displaceable along a linear treatment zone, and a support configured to be temporarily fixable to the workpiece.

Abstract: The invention relates to a laser spot welding process for executing a spot weld in two successive steps, namely a first step of preparing the surface state of the material to be welded and a second step of welding as such. The luminous energy (BR) reflected by the weld region of the material is measured in real time during the first step and then processed by a controller circuit (37) connected to a control circuit (30) of the laser source (31). In this way, the characteristics (LM) of the laser beam are adjusted in real time as a function of the measurements effected to allow effective control of the quality of the weld obtained, and in particular of its dimensions. The invention also relates to a welding device for implementing this process.

Abstract: A laser welding pressure unit comprises a housing, a rotating element, and a foot. The housing may attach to a laser head. The rotating element may include an outer ring rotatably coupled to an inner ring, wherein the outer ring is coupled to the housing. The foot may couple to the inner ring such that the foot rotates with respect to the housing. The foot may also be configured to contact an upper surface of a metal sheet and may be oriented such that while the metal sheet is being welded, the foot rotates about a central vertical axis and the laser welding pressure unit is able to move in any direction without the foot breaking contact with the surface.

Abstract: An approach for assembling and repairing probe assemblies using laser welding includes aligning a beam element to a post element on a probe substrate. The beam element is positioned in contact with the post element on the probe substrate. The beam element is then attached to the post element on the probe substrate by laser welding the beam element to the post element on the probe substrate. The approach may include the use of a vacuum capillary pickup tool to align and position the beam element. The vacuum capillary pickup tool may also operate in conjunction with a laser beam delivery system for guiding the laser beam to the correct location for welding and also to assist in removing gases and debris attributable to the laser welding process. The approach allows probe elements to be connected directly to a probe substrate without requiring an intermediate layer.

Abstract: An embodiment of the invention comprises a method associated with a PCB having a first component, and a second component, that has substantially less thermal mass than the first component. During an initial time period, the PCB and its components are placed at an initial position proximate to a first heat source, which is operable to provide heat energy in accordance with a thermal profile comprising successive phases. After the initial time period, the first heat source is operated during each of the phases in accordance with the thermal profile to selectively apply heat to the PCB and to the plurality of components thereon. During the initial time period or a specified one of the phases, selectively, heat energy from a focused heat source is directed only to the first component, and not to other components.

Abstract: A hybrid welding apparatus, and a system and method for welding at least two adjacent components having a large gap of approximately 3.0 millimeters that results in a full-penetration weld is provided. The welding system includes a hybrid welder having a defocused laser beam, an electric arc welder, and at least one bridge piece adjacent to one or more of the at least two adjacent components. The defocused laser beam and the electric arc welder are arranged and disposed to direct energy onto the at least two adjacent components to create a common molten pool operable to provide a full penetration weld to bridge the gap at a high constant weld speed, thereby joining the two adjacent components with a weld.

Abstract: The invention relates to a modular system for overlay welding at inwardly disposed surfaces of workpieces using a laser beam. In this respect, a coating can be formed on inwardly disposed surfaces using a powdery welding material. It is the object of the invention to provide possibilities for the overlay welding or for the coating of inwardly disposed surfaces of workpieces with a variable immersion depth, increased flexibility and independence of direction in the processing. A feed for powdery welding material, a feed for protective gas and a feed for a coolant are present on a system in accordance with the invention. The system is formed with a coupling module for the laser beam, at least one beam guiding module for the laser beam and a processing module, which can be connected to one another. A collimated laser beam is directed via the coupling module through the beam guiding modules) onto an optical element focusing the laser beam on the surface of a workpiece to be processed.

Abstract: This robot system includes a robot, a laser emitting portion moved by the robot, capable of scanning a welding locus with a laser beam at least in a state where the laser emitting portion is not moving, and a control portion controlling the laser emitting portion to scan the welding locus with the laser beam in order to perform welding with weaving on the welding locus at least in the state where the laser emitting portion is not moving.

Abstract: The present invention relates to a laser welding method of welding an electrode and a cable core to each other satisfactory by irradiation of a laser beam, even when the core is thin and the area of the electrode is small. The laser welding method welds on a substrate the electrode and the core of a coaxial cable to each other by irradiation of the laser beam. The core is sandwiched between a pressing member and the electrode, while the electrode and the core are brought into contact with each other at a connection section. The pressing member is a member that is transparent to the processing laser beam. A part of the core is molten by radiating the laser beam from the pressing member side. As a result, the electrode and the core are connected with each other.

Abstract: In a laser welding method including irradiating a welding portion between metallic members with a laser beam, the laser welding portion is covered with a cover made of a laser beam transmissive resin, and the metallic members are laser-welded together by irradiating the welding portion with the laser beam through the cover. The cover made of the laser beam transmissive resin may come in contact with the metallic members around the welding portion so that a gap is formed between the cover and the laser welding portion, thereby holding the gap in a hermetically closed state. It is therefore possible to provide a laser welding method between the metallic members for preventing metal particles that have spattered out of the welding portion from dispersing into surrounding areas.

Abstract: A welding system and method includes a main torch including a main electrode configured to form a first arc with a base metal; a first bypass torch including a first bypass electrode configured to form a second arc with the main electrode; and a second bypass torch including a second bypass electrode configured to form a third arc with the main electrode.

Abstract: A welding apparatus for welding a work-piece includes an energy source configured to generate a weld in a zone of the work-piece, with the work-piece characterized by a layer. The apparatus also includes a first wheel characterized by a first circumference and a first set of protrusions disposed on the first circumference, and a second wheel characterized by a second circumference and a second set of protrusions disposed on the second circumference. Each of the first and second wheels is configured to rotate relative to the work-piece, and the first and second sets of protrusions are configured to disrupt the layer as the work-piece is traversed between the first and second wheels. The energy source generates the weld in the zone of the work-piece following the disruption of the layer. A method employing the disclosed welding apparatus is also provided.

Abstract: A welding technique closely contacting a light transmissive second member to a first member and radiating deflection-controlled laser light from a second member side to weld both first and second members at a weld interface thereof. A reflectance reducing means is formed by an incident angle adjusting step provided in a cover plate that is disposed on a light radiating surface side of the second member. The reflectance reducing means reduces incident angles of the light at the light radiating surfaces of the first and second members, thus reducing the reflection loss of the laser light at the light radiating surfaces and improving the welding efficiency.

Abstract: A spatter removing device for a laser welder including an optic head to which a laser beam is transferred through an optic fiber from a laser oscillator, a cross jet mounted at one side of a lower end portion of the optic head, a safety cover provided at the outside of the optic head so as to surround the optic head, and a material injection unit that injects a material to be welded below the optic head, the device includes a discharge unit and a spatter cooling device. The discharge unit is provided with a discharge pipe that discharges a welding gas and the spatter at one side portion of the safety cover. The spatter cooling device is connected to the discharge pipe and cools the spatter so that the spatter is forcibly collected.

Abstract: A method for joining a workpiece by means of a welding head, in which at least one line of light is generated on a workpiece, which crosses a joint line at a site to be joined and a joint seam generated at a joined site after processing. The lines of light are imaged at the site to be joined and at the joined site in order to generate reference data relating to the geometry of the site to be joined and measurement data relating to the geometry of the joined sites. The reference data and the measurement data are then compared at one and the same workpiece site before and after processing, in order to determine the geometry of the joint seam independently of the geometry of the site to be joined.

Abstract: A welding apparatus for an induction motor includes a fixture operable to support a rotor and rotate the rotor about an axis of rotation of the motor, and a welding head supported adjacent the fixture and operable to weld conductor bars located about the surface of the rotor to the first shorting ring when the fixture supports the rotor. A controller controls the fixture to selectively rotate the rotor. The controller moves the welding head, the fixture, or both, so that the welding head is in a welding position, and causes the welding head to weld the conductor bars to the first shorting ring while remaining in the welding position, with the rotor rotating to create a substantially circular weld path along the first shorting ring. In some embodiments, the conductor bars are welded to both shorting rings simultaneously. A method of welding an induction motor is also provided.

Abstract: A shielding gas (SG) flow controller for an arc welder includes SG input/output with a controllable valve therebetween, and having a control input, and a controller having a first input receiving a welding signal representing arc current and a gas flow setting controller generating a flow setting output based on the welding signal, representing a desired SG flow. Input and output pressure sensors provide SG input and out pressure to second and third controller inputs, respectively. A flow setting output modifier modifies the flow setting output of the gas flow setting controller based on the SG input/output pressure, the welding signal, and a characteristic of the controllable valve into a control signal input to the control input of the controllable gas valve to maintain a substantially constant SG flow corresponding to the flow setting output substantially independent of actual SG input/output pressures.

Abstract: Manufacturing a coil with high precision and high efficiency. Device for manufacturing a coil 3 by welding U-shaped pipes 2 at both ends of a plurality of straight pipes 1. Providing a laser welding head 11 which uses a condensing lens 15 having a focal length at least twice the diameter of the pipes 1, 2 to be welded, to perform welding by irradiating a laser light 13 onto the straight pipes 1 held in position by a workpiece setting jig 24, and onto a joint position w of U-shaped pipes 2 which are temporarily fitted to both ends of the straight pipes 1. Making it possible to manufacture a coil with high precision and high efficiency, without using a filler wire.

Abstract: A welding method and apparatus for welding workpieces together by conducting a forward hybrid welding process on a joint region that includes a weld seam defined by and between faying surfaces of the workpieces, and then conducting an aft hybrid welding process on the joint region. The forward hybrid welding process simultaneously causes a forward laser beam and a forward electric arc to travel along the joint region, which in combination penetrates the weld seam and forms a weld pool that solidifies to form a weldment. The aft hybrid welding process utilizes an aft electric arc and an aft laser beam to produce a second weld pool that remelts and mixes with the weldment. On cooling, a weld joint is formed that is capable of deeply penetrating the weld seam of the joint region.

Abstract: A welding method and apparatus for welding workpieces together by conducting a laser beam welding process on a joint region that includes a weld seam defined by and between faying surfaces of the workpieces, and then conducting a hybrid laser arc welding process on the joint region. The laser beam welding process entails causing a first laser beam to travel along the joint region, penetrate the weld seam and form a weldment. The hybrid laser arc welding process remelts the weldment by simultaneously causing an electric arc and a second laser beam to overlap and travel along the joint region and form a weld pool in the weldment. On cooling, a weld joint is formed within the joint region and its weld seam.

Abstract: An arrangement for the repair of BLISK blades damaged at their leading and trailing edges by use of laser deposition welding, includes a laser source and laser optics for generating a focused laser beam (26) and a powder line (35) connected to a powder reservoir for supplying metal powder to be melted by the laser beam to the weld area. A modular, tubularly elongated welding apparatus (7) with a connection module (13) which is connected to a laser source and in which the entering laser beam is deflected in longitudinal direction and parallelized, and to the one side of the connection module (13) is connected to a camera module for a CCD camera (12) enabling the precise positioning of the welding apparatus and the deposition of the molten metal powder on the respective blade to be monitored and controlled.

Abstract: Parts are welded by way of a laser beam, wherein the parts are oriented and fixed relative to each other, a laser beam is introduced into an upper part from above and centered relative to a joint point and fuses only the inner region directly above the joint point, while the upper part and the lower part are pressed against each other and therefore move toward one another, wherein the fused region of the upper part penetrates the material of the particular lower part, which has likewise fused in the meantime. Laser welding makes it possible to weld the parts so as to form products having nearly any type of geometry with much less effort than with resistance welding or capacitor discharge welding. The welding device needs only hold and fix the parts to be welded, and apply the slight surface pressure required.

Abstract: A welding system is provided, in which two electrodes are directed at a joint between two work pieces and the electrodes are energized with DC pulse or AC welding waveforms at a controlled waveform phase angle. The systems include a synchronizing controller to synchronize the welding waveforms, and a work point allocation system provides one or more work point values to the welding machines to provide synergic control of the welding according to a user selected system work point value or parameter. The systems and methods further provide for synchronized work point value modulation for the opposite sides of a dual fillet weld. The system and method further provide a high energy heat source that directs intense heat at a portion of the weld joint to improve weld penetration.

Abstract: Powder-delivery apparatus for delivering powdered cladding-material into the vicinity of a laser-beam spot includes a plurality of powder-delivery modules. Each of the modules is arranged to receive the cladding-material and deliver the cladding-material through a plurality of nozzles. The position of the nozzles in the modules with respect to the laser-beam spot is adjustable in three Cartesian axes. The modules are selectively removable from, and attachable to the apparatus. Nozzles in any one of the modules can be selectively prevented from delivering cladding-material.

Abstract: A tube matrix and the corresponding method of joining a plurality of tubes to a base plate to create the tube matrix. The tube matrix has a base plate from which a plurality of parallel tubes extend. The base plate has holes formed though it to receive the tubes. The tubes are placed into the holes on the base plate. The tubes may have end flares that abut against the base plate and prevent the tubes from completely passing through the base plate. Once the tubes are in place in the holes of the base plate, the tubes and base plate are welded together with individual laser welds. The laser welds enable a very dense matrix of tubes to be welded to the base plate without damaging or obstructing the tubes.

Abstract: The invention relates to a method for connecting the ends of steel tubes by means of orbital welding using a hybrid laser arc technique, with the tubes preferably having wall thicknesses ?6 mm and more particularly ?12 mm and diameters of preferably ?150 mm, the ends of which tubes are connected by one or more welding passes, wherein the laser and arc welding heads as tools are guided over a guide ring fixedly arranged around a tube end in the region of the weld site during the welding and are displaced around the tube diameter. The invention also relates to a device for carrying out the method, wherein the laser and the arc welding heads are positioned separately on the guide ring and are moved over the tube circumference and controlled independently of one another during the welding process.

Abstract: A method and apparatus for fabricating a foam container by using a laser cutting apparatus to precisely cut and remove portions of foam in order to form custom and predetermined text, indentations and protective compartments in the foam, and more particularly a method of controlling the laser relative to high density foam to create precise cuts completely through the foam without subsequently adjusting the focal point of the laser, the cuts being made according to exterior dimensions of an object to be supported and protected in the high density foam.

Abstract: A welding system is described as having an energy source, in particular a laser beam source, for implementing a heat transfer for welding a first component to at least one second component in a connection area and having a sensor for detecting the processing radiation of the welding procedure. The sensor includes a measuring probe. Also described is a welding method.

Abstract: A method of manufacturing a vehicle structure including a laser welded fastener includes positioning a first panel in engagement with a second panel to provide access to the first panel by a laser beam. The first panel is laser welded to the second panel. A fastener including projections axially extending from a first surface of a flange are formed. The projections are engaged with a surface of the first panel to space apart the first surface of the flange from the surface of the first panel. Laser welding is initiated by directing a laser beam toward one of the flange of the fastener and the first panel. Gas is vented from an area between the first surface of the flange and the surface of the first panel. The flange is laser welded to the first panel.

Abstract: In a mirror for an automobile, the adoption of resin mirror body to a mirror plate can decrease the weight of the mirror body, and the mirror plate is fixed onto a mirror holder through the welding. Therefore, this eliminates the usage of both-sided adhesive tape or adhesive agent, makes assembly processes less complicated, and thus the reduction in production cost is achieved. Furthermore, since the mirror plate can be fixed onto the mirror holder firmly and strongly even when the mirror plate is not pressed strongly to the mirror holder, excessive load on the mirror holder or the mirror plate becomes avoided. In addition, at the time of the production stage, some dimensional variation in the edge part of the mirror holder or the peripheral edge of the mirror plate becomes easily acceptable.

Abstract: Described herein is a method for controlling the quality of a laser-welding process, for example of laser welds of semifinished products constituted by elements of sheet metal of different thickness and/or properties (“tailored blanks”), of the type that comprises the steps of: detecting a radiation (E*) produced in the welding area (2, 3) and issuing signals (E*) indicating said radiation; acquiring and processing said signals (E*) indicating said radiation; making a division into blocks of said signals (E*) indicating said radiation; calculating (205) for each block a block-mean value (u) and a value of block standard deviation (o); and in supplying input values comprising block-mean values (u) and values standard deviation (o) for identifying defects and/or porosities and insufficient penetration.

Abstract: A pipe production system includes a plurality of platform segments that are coupled together at a construction site to form a work platform. A helical pipe production system is mounted on the work platform. The work platform includes an integrated drive system that enables the platform to be moved around the terrain of the construction site so that pipe can be produced in-line with an intended or desire pipe laying path.

Abstract: Welding quality of a welding section W welded by laser welding is determined by acquiring an image of the welding section W and its surrounding region by means of a high-speed camera 11, analyzing, as parameters, the number of spatters P per unit length and the area of a high-luminance region in the acquired image by means of an analyzer 12, and comparing the analyzed parameters with respective comparison tables created beforehand, to determine the welding quality of the welding section Wa. Information on the welding quality of the welding section W is displayed on a monitor 13. Not only the laser welding quality of the welding section can be determined but also in-process shearing strength prediction as well as in-process fracture mode prediction can be performed, thus enabling quality control matching high-speed and high-precision laser welding.

Abstract: A gripper device for laser welding and vision inspection is provided which includes a frame unit releasably mounted on a front end of an arm of a robot and a clamping unit mounted on the frame unit. Additionally, embodied in this single gripper device is a laser-vision exchange (first) module, a laser-vision sharing (second) module and a laser-vision target (third) module all embodied in a single gripper device to irradiate laser beam for welding a welding object and obtain a vision source of an inspection object.

Abstract: A laser processing system includes a laser processing head, a powder supply device, and a controller. The powder supply device supplies powder to the laser processing head. The laser processing head includes: a laser emission unit which irradiates a workpiece with laser light; and a powder supply unit which receives the powder supplied from a powder supply device to the laser processing head, and can supply the powder to a laser spot on the workpiece. The powder supply unit includes: a powder discharge unit which can discharge the powder toward the laser spot on the workpiece; and a powder-supply control mechanism which controls the amount of the powder to be supplied to the powder discharge unit, by distributing to the powder discharge unit at least a part of a flow of the powder supplied from the powder supply device. The controller controls the distributing by the powder-supply control mechanism.

Abstract: A laser-welding apparatus may include a laser source, an incoming laser beam produced by the laser source, and a beam splitter that splits the incoming laser beam to form a leading beam and a trailing beam. A first focusing lens may focus the leading beam and a second focusing lens may focus the trailing beam to form a trailing-beam pattern on a workpiece. The trailing-beam pattern may include a crescent-shape having arms and a tail portion.