Laser fusion cutting of stainless steel is often considered in a material range from 0,3mm up to 4mm and laser powers up to 2kW. For a given material thickness, different optimum beam and process parameters can be determined empirically, leading to a dross-free cut for high tool travel speeds. Realising sharp 90-degree corners, dross formation is observed and leads to a deteriorated cutting quality. With reorientation at small radii, the speed-dependent change in the cutting process is superimposed by the existing beam to nozzle misalignment and contributes to the stability of a cut. The feature radius R on the stability of the cutting process is being determined by reducing feature radius R. In this paper, cutting of different radii for different sized conventional nozzles is considered and analysed. Based on cutting quality evaluation, fine feature cutting is defined by discussing thickness-dependent finest cutting feature for a given gas dynamic input.
High contrast marking of metals is used in a wide range of industries. Fiber laser marking of these metals provides non-contact marking with no consumables, offering many advantages over traditional methods of metal marking. The laser creates a permanent mark on the material surface combining heat and oxygen with no noticeable ablation. The focussed beam of the fiber laser in combination with precision control of the heat input is able to treat small areas of the material surface evenly and consistently, which is critical for producing black anneal marks. The marks are highly legible which is ideal for marking serial numbers or small data matrices where traceability is required. This paper reports the experimental study for producing black anneal marks on various grades of stainless steel using fiber lasers. The influence of metal surface finish, beam quality, spot size diameter and pulse duration are investigated for producing both smooth and decorative anneal marks.
Medium and high-power fiber lasers operating in the 1um region have proven their capabilities for cutting and welding
in industrial manufacturing applications. This paper reviews the process performance capabilities of medium power (up
to 500W) fiber lasers in a range of precision cutting, fusion-welding and additive manufacturing applications.
High performance fibre lasers are now well established as an extremely robust and reliable technology enabling a
growing and diverse number of demanding industrial and medical and applications. Compared to rival technologies,
such as carbon-dioxide (CO2), Lamp/Diode-Pumped Solid-State (L/DPSS) and disk lasers, fibre lasers offer a number of
unique characteristics that have resulted in their wide adoption in an increasing number of industrial sectors. In addition
to replacing conventional lasers in existing applications, fibre lasers have been very successful in enabling new
applications, both factors which explain their increasing market share. In this paper we describe the basic features of
fibre lasers, and discuss their generic advantages compared with other laser technologies and consider how these may
translate to defence applications. We explain our proprietary cladding-pumping technology (GTWaveTM) and the laser
architectures we use to implement our commercial products. We present parametric performance data that show the vast
range of pulse waveforms that can be produced and discuss some new industrial applications that they have recently
enabled. Finally, we reference some of the leading research results for multi-kW continuous-wave (CW) fibre lasers and
summarise SPIE's published work in this field.
Fiber-integrated high power fiber lasers (HPFLs) have demonstrated remarkable levels of parametric performance, efficiency, operational stability and reliability, and are consequently becoming the technology of choice for a diverse range of materials processing applications in the "micro-machining" domain. The design and functional flexibility of such HPFLs enables a broad operational window from continuous wave in the 100W+ power range, to modulated CW (to 50kHz prf and above), and to quasi-pulsed operation (kW/μs/mJ regime) from a single design of laser system. A long-term qualification program has been successfully completed to demonstrate the robustness and longevity of this family of fiber lasers.
In this paper we report for the first time on the power-scaling extension of SPI's proprietary side-coupled cladding-pumped GTWaveTM technology platform to output power levels in the multi-hundred watt domain. Fiber and system design aspects are discussed for increasing both average power and peak power for CW and quasi-pulsed operation respectively whilst maintaining near-diffraction limited beam quality and mitigating non-linear effects such as Stimulated Raman Scattering. Performance data are presented for the new family of laser products with >200W CW output power, M2 ~ 1.1 and modulation performance to 50kHz: Furthermore, the modular, flexible approach provided by GTWaveTM side-pumped technology has been extended to demonstrate a two-stage MOPA operating at >400W.
High Power Fiber Lasers (HPFLs) and High Power Fiber Amplifiers (HPFAs) promise a number of benefits in terms of their high optical efficiency, degree of integration, beam quality, reliability, spatial compactness and thermal management. These benefits are driving the rapid adoption of HPFLs in an increasingly wide range of applications and power levels ranging from a few Watts, in for example analytical applications, to high-power >1kW materials processing (machining and welding) applications. This paper describes SPI’s innovative technologies, HPFL products and their performance capabilities. The paper highlights key aspects of the design basis and provides an overview of the applications space in both the industrial and aerospace domains. Single-fiber CW lasers delivering 1kW output power at 1080nm have been demonstrated and are being commercialized for aerospace and industrial applications with wall-plug efficiencies in the range 20 to 25%, and with beam parameter products in the range 0.5 to 100 mm.mrad (corresponding to M2 = 1.5 to 300) tailored to application requirements. At power levels in the 1 - 200 W range, SPI’s proprietary cladding-pumping technology, GTWaveTM, has been employed to produce completely fiber-integrated systems using single-emitter broad-stripe multimode pump diodes. This modular construction enables an agile and flexible approach to the configuration of a range of fiber laser / amplifier systems for operation in the 1080nm and 1550nm wavelength ranges. Reliability modeling is applied to determine Systems martins such that performance specifications are robustly met throughout the designed product lifetime. An extensive Qualification and Reliability-proving programme is underway to qualify the technology building blocks that are utilized for the fiber laser cavity, pump modules, pump-driver systems and thermo-mechanical management. In addition to the CW products, pulsed fiber lasers with pulse energies exceeding 1mJ with peak pulse powers of up to 50kW have been developed and are being commercialized. In all cases reducing the total “cost of ownership” for customers and end users is our primary objective.