Laser Beam Welding (LBW) finds widespread use in industries like naval and automotive. To meet the demands of complex welding processes, higher power lasers have been developed. However, conventional refractive optics limit power utilization, affecting robustness. Multi-Plane Light Conversion (MPLC), a fully reflective technology, enables complex beam shaping with 16kW lasers. A MPLC-based laser head with an 800µm annular shape at 1µm wavelength has been developed. LBW of 304L stainless steel (6mm thick) at 7kW and HLAW of steel (16kW) with 23mm penetration depth are successfully demonstrated. MPLC's extended depth of field improves welding efficacy, showcasing its potential in advancing laser welding applications.
Laser Powder Bed Fusion (LPBF) is a critical additive manufacturing process known for its accuracy and complexity in producing intricate parts. However, challenges like limited production speed, hot cracking, and material restrictions hinder its efficiency. This study explores the use of Multi-Plane Light Conversion (MPLC) as a beam shaping solution to improve LPBF. By applying MPLC, we achieve faster printing while maintaining high-quality parts. Comparative analysis demonstrates the superiority of MPLC-based beam shaping in enhancing process yield and manufacturing efficiency.
Dielectrics cutting with Bessel beams formed by an axicon is nowadays a well-known technique. Typically, the axicon is used in transmission to form the elongated Bessel beam. In this contribution, we report on dielectrics cutting with a femtosecond laser using a reflective axicon and compare the results in terms of surface roughness of the cutting planes with those obtained with a standard refractive axicon. Moreover, we couple the spatial beam shaping with temporal beam shaping applying MHz- and GHz-bursts of femtosecond pluses.
Ultra-short pulse lasers have become indispensable in industrial and scientific micro-processing applications, offering advantages like surface texturing, treatment, drilling, and micro-welding. However, these applications also present unique challenges, including process speed, precision, and seamless integration into industries. This paper explores how beam shaping addresses these challenges in micro-processing. Various beam shapes, such as beam splitting, non-diffractive beams, top-hat shaping, U-shaped beams, and triangular beams, are discussed for improving process speed, precision, and integration of ultra-short pulse lasers. The paper also addresses the challenges of fibering the laser for industrial integration and how beam shaping overcomes these hurdles. In conclusion, beam shaping proves to be a valuable tool for tackling the unique challenges of micro-processing with ultra-short pulse lasers, enhancing process speed, precision, and integration into various applications.
Beam shaping has gained increasing importance in laser-based processing, offering enhanced efficiency, quality, and precision across various applications. This paper discusses the challenges of characterizing and defining criteria for evaluating shaped beams in laser material processing. It highlights the essential role of beam shaping in Continuous Wave (CW) processes like high-quality welding for e-mobility and pulsed applications like surface texturing. Various beam shaping technologies are explored, and criteria such as efficiency, uniformity, sharpness, robustness, and depth of field are proposed for evaluating beam performance. Proper characterization and evaluation of shaped beams are crucial to optimize laser performance, ensuring reliable and repeatable outcomes in laser-based processes.
The aim of this work is to demonstrate the processing of large metal foils by femtosecond laser in a roll-to-roll configuration using 2D Direct Laser Interference Patterning generate by MPLC technology, as an advanced surface functionalization for high-throughput manufacturing. Highly uniform 2D morphologies have been created on stainless steel, with a spatial periodicity of 14µm and an aspect ratio up to 0.7, suitable for numerous applications such as de-icing.
Laser welding is crucial for manufacturing e-mobility components, particularly copper and aluminum parts. However, their high reflectivity and thermal conductivity present challenges, leading to inadequate penetration and weaker welds. Beam shaping offers a promising solution by modifying the laser beam's intensity distribution. In this study, we demonstrate successful welding of aluminum battery cases, copper busbars, and hairpins using Multi-Plane Light Conversion for beam shaping. Results show improved weld quality, reduced defects, and enhanced mechanical properties. The technique provides a higher depth of field and an extra degree of freedom for optimizing weld quality, promising efficient and reliable manufacturing of e-mobility components.
Riblets manufacturing allow the reduction of flight consumption of 2 to 3% but requires both high precision in texturing and high processing speed to engrave large surfaces. An innovative combination of high-speed (100 kHz) and high energy (3 mJ) femtosecond laser with a beam division up to 9 spots, and a square shaping of the spots is presented using multi plane light conversion (MPLC) beam shaping technique for both the beam division and the square beam forming, with homogeneity of spots better than 95%. Texturing tests will be presented and compared to achievements using non shaped Gaussian laser beams.
We describe how to improve micro-processing using Second Harmonic Generation of a Ultra-Short Pulse laser combined with a Multi-Plane Light Conversion beam-shaper.
Manufacturing at 515nm presents advantages compared to 1030nm : extended depth of field, higher sharpness, and higher ablation efficiency for some materials. The beam-shaper provides a square top-hat with a 1/10 sharpness and an extended depth of field up to 10 times higher compared to other beam-shaping technologies.
We describe process results of different metal samples: LIPSS generation with a 100µm square targeting a period down to 0,5µm and holes drilling holes of a diameter smaller than 10µm.
Femtosecond lasers are available with an increasing energy per pulse. Their efficient exploitation without any decrease of quality is key. It could be done with beam-splitting and parallel processing.
We present a fully reflective CANUNDA-SPLIT module used with a 100W 1030nm 500fs laser and a 100mm F-theta. The uniformity of the beams over the Field of View is presented.
The drilling of stainless steel and Nickel cavities matrices, designed for tribological properties improvement, has been performed. The homogeneity of the cavities and the circularity are analyzed. These results paves the way to meter-scale area processing with a reduced processing time.
Industrial molds used to manufacture new type of Fresnel lenses require significant control over the size and shape of the ablation grooves. In particular, for demanding patterns, the objective is to obtain asymmetrical triangular grooves of around 10-20 μm width, micromachined with an ultra-short pulse (USP) laser for a better quality. To obtain this ablation profile we use a specific triangular beam shape obtained thanks to a reflection beam-shaping module. The idea is to move and rotate this triangular shape to have one of the edges of the triangle on one side of the groove, and its opposite point on the other side. In order to have total control of the laser process, we have collected a large amount of data of laser parameters, beam profiles and ablated groove profiles. This database allows us, thanks to the use of a deep learning algorithm, to predict the ablation profile from a set of laser parameters and beam profile pictures used for machining. The use of an artificial intelligence algorithm is justified by the fact that, at such a low resolution and with femtosecond laser pulses, light-matter interactions become complex, in particular due to nonlinear effects, which make using simulations difficult. Our deep learning model has the particularity of being a ”hybrid” model using several types of data: laser parameters, curves and images. This allows the algorithm to have an overview of the process but also to give the end-user a very fine control.
Laser Beam Welding (LBW) of complex materials, such as ferritic and austenitic steel, is challenging. An appropriate beam shape improves the process by stabilizing the keyhole.
A methodology for tailoring the beam shape has been developed. The appropriate shape for LBW of 1mm thick steel is an inner intense spot and a background top-hat shape.
A dynamic beam shaper based on Multi-Plane Light Conversion has been developed: the ratio between the shapes and the back shape dimensions can be adjusted. The optical performance and the impact on the quality of the process with a 8kW 1.07µm laser are described.
The laser technology is key to the development of the e-mobility. We demonstrate how an optimal laser beam shaping enables high speed and high quality copper welding for the battery cells manufacturing.
The beam shaping parameters are explored and optimized and the optical performance is assessed. The process window is described for four sets of shape parameters as well as the comparison with an unshaped beam. The quality in each cases for different speed and average power is discussed. An optimal process at 6m/min and 8kW is obtained. At last, different welding configuration, such as transparent welding, are described.
The development of composite-based manufactured parts has been led, by the need of the aerospace industry to reduce the weight of aircrafts while maintaining a very good structural performance. The trend to use thermoplastic instead of thermoset resin enables even lighter parts, nevertheless it involves laser heating instead of IR lamp heating.
We describe the development of a laser beam-shaper based on Multi-Plane Line Conversion technology delivering a tailored top-hat beam profile on the composite fiber to optimize its consolidation and therefore final properties. We demonstrate the performance of the process and describe the optical performance of the beam shaper.
The development of LBW processes is driven by more complex laser-based welding processes made possible with the development of lasers of higher available power. Nevertheless, most laser-heads are based on refractive optics, limiting the capability to fully use this power. Multi-Plane Light Conversion (MPLC) is a fully reflective technology enabling complex beam shaping through a succession of phase plates. A MPLC-based laser head has been developed providing an annular shape. It presents a less than a 1mm focus shift. LBW as well as HLAW of steal up to 16kW is demonstrated with improved butt-joint configuration gap welds.
Laser cutting process is a very broad application requesting a high beam quality. Optimizing the beam shape is a promising solution to the challenge of cutting thicker parts while maintaining a sufficient cutting speed.
We describe here a beam shaper compatible with industry standard equipment handling up to 16kW average power delivering an optimized non-symmetric shape. The different shapes are examined by means of online high-speed X-ray images, enabling to reconstruct the cutting front and to calculate the absorbed irradiance on the processed sample. This allows to compare the results with conventionally processed samples.
Laser microprocessing using Ultra-Short Pulse lasers has developed thanks to the achieved process quality. The main challenge of those processes is the yield improvement. This study will focus on yield improvement of applications such as such as probe card manufacturing for electronic applications with a green USP laser using beam splitting.
We present here a fully reflective beam splitter compatible with 500fs green lasers. The compatibility with an industrial machine is demonstrated through a F-theta lens, as well as through a precession head. We show here the process results including the repeatability of the pattern, and the achievable ablation rate.
Micro processing applications using femtosecond lasers have developed thanks to the quality of the process. A challenge still to be addressed is the capability to deliver the beam through a fibre. One solution is the use of hollow-core inhibited coupling fibres, nevertheless its use requires a beam stabilization to insure a stable operation.
This study attempts to qualify two beam stabilisation systems: two piezo motors coupled with four quadrant detectors and Cailabs’ all-optical mode-cleaner system based Multi-Plane Light Conversion (MPLC) technology. To do such output fibre transmission efficiency and beam quality are investigated under controlled fluctuation of beam pointing.
The microfluidics field, due to its various possibilities in the study of chemical and biological reactions with only few consumables, is expanding significantly. A flexible solution has been developed based on Ultra-Short Pulsed laser technology to engrave different microfluidic channels on a chip, and to seal them.
We describe here a solution to improve the welding’s speed and quality based on a tailored beam shaping with Multi-Plane Light Conversion (MPLC) technology. The fully reflective module is used with a high-power femtosecond laser. The optical performance of the module and achieved improvement on the welding are detailed.
Complex touch panel displays development is requiring high performance glass cutting techniques. Femtosecond lasers, combined to Bessel beam generation based on reflective axicons already showed quality and efficiency improvements, while being able to handle high peak and average power.
We described here recent developments for high quality Bessel beam generation using a fully reflective system. This complex Bessel beam presents an intensity plateau along its propagation axis, being twice more homogeneous and having a five times sharper tail compared to a classical Bessel beam. This development paves the way to complex and selective multi-layer glass cutting.
Multi-kilowatt Laser Beam Welding (LBW) processes must take up three challenges to keep improving its performance: handling high power, shaping the output beam and reducing focus shift. This will lead to a higher quality and speed as well as the capability to weld thicker parts.
We describe here a beam shaper compatible with industry standard equipment (collimation and focusing modules, arm robot and laser) handling up to 16kW average power delivering a mm-wide annular shape and reducing the focus shift. The LBW processes improvements on different materials are described.
Multi-Plane Light Conversion (MPLC) is an innovative shaping technique which allows theoretically lossless complex beam shapes. The free-space reflective design is particularly well suited to Ultra-Short Pulse (USP) laser-based processes challenges. We demonstrate the system high stability over long processing times thanks to a mode cleaning feature.
Here we show micro-cutting and engraving tests carried out on stainless-steel and brass with a high power, industrial, USP laser having squared, and circular top-hat profile generated using MPLC technology. Thanks to the sharp edges of the profile, a sensible reduction of the taper and optimization of the overlapping is observed
The recent development of Ultra Short Pulse lasers has widely broadened the range of possibilities of laser material processing. Associated with a proper beam splitting it enables adding to the surface new properties by texturing it.
We present here a fully reflective three by three beam splitter compatible with high power up to 300W with 500fs pulses lasers. The process results are presented including the repeatability of the pattern, and the achievable ablation rate. The pattern is 15µm waist gaussian beams with 300µm pitch.
Compatibility with scanning system and F-theta lenses, enabling micro-processing throughput improvement, is described.
With the development of touch panel display the need to process thinner glass using Ultra-Short Pulse (USP) laser has increased. Beam shaping improves the process yield and quality but requires specific precautions when applied to USP laser due to high peak power and dispersion.
Bessel beams improve the quality of glass drilling and cutting due to the extended depth of field. We present Bessel beam generation using a reflective off-axis axicon giving a more stable beam compatible with scanning system and with a profile closer to theory. The characteristics of the beam and of the processed glass are described.
Multi-kilowatt Laser Beam Welding processes are facing new challenges: reducing the final parts weight and improving reliability to decrease the amount of discarded parts. Appropriate beam shaping enables those improvements by decreasing the process defects and by allowing welding of new types of materials and of thinner parts.
We describe here the design and the process test results of a fully reflective beam shaper laser head compatible with high-power lasers demands integrated on a robot. The high efficiency cooling permitted by a reflective design reduces focus shift. A mm-wide annular shape onto the processed part enables melt pool size control.
Generation of nano or micro-scale structures on materials surface enables new functions and properties, such as super-hydrophobicity by lotus effect, surface blackening by light trapping, modification of surface tribological properties, etc. which are in high demand for a wide variety of industrial fields. Amongst the surface functionalization techniques, Ultra-Short Pulse lasers have been proven to be a reliable tool to create Laser Induced Periodic Surface Structures (LIPSS). Exploitation of LIPSS for industrial purposes poses some key problems like up scaling over large area with high repeatability and high throughput. Beam shaping could be a key element to overcome these issues. Specific shapes, such as top-hat line shape, could enable at once uniform processing over large surface with the consequence to reduce the processing time. Multi-Plane Light Conversion (MPLC) is an innovative technique of beam shaping which allows theoretically lossless complex beam shapes with a high control over amplitude and phase. The free-space reflective design allows for high beam shaping quality whilst maintaining the ultra-short property of the laser pulses, which is not usually achievable through other beam shaping methods. Here we show the results obtained over Stainless-Steel using an industrial femtosecond laser with a tophat line of 30μm × 594 μm intensity profile generated using MPLC technology. The beam has been delivered over the Stainless-Steel surface with a galvo scanner and focused through an f -theta lens of 100 mm. Surface morphology has been investigated via SEM and the processing time has been compared to conventional round Gaussian Beams
The development of a multisensor optronic device requires Size, Weight and Power (SWaP), cost-effective and modular rangefinders while keeping a good range performance. We report on a fully fibered monostatic laser rangerfinder based on a one lens collimator used as the aperture of both the emission and reception channels. This has been possible thanks to the use of a diplexer.
This design makes the system compacter and achieves a 200g system weight. In addition to its low volume, the fully fibered architecture allows designing a building block rangefinder with the collimator sub-system on one side and the laser and electronics cards module on the other side. Both are linked up by only an optical fiber. This kit format enables the rangefinder to better fit in any available space in higher level systems such as gimbals and multi-function imagers. Besides, no alignment is needed, and no parallax error is possible: the alignment between channels is guaranteed by design over the whole range.
The emission/reception channels of the first prototype has a 28mm diameter 80mm focal length lens, and a 1.55μm 100μJ pulsed laser firing in a burst mode. The rangefinder is set in a class 1 configuration, and measures at 1Hz. The achieved Extinction Ratio is 30dB, which is equivalent to a range on NATO targets of 7km. The achieved ER being class 1M at 5Hz is even 32dB, which is equivalent to a range of 8.5km on NATO targets.
More configurations are reported in this article with their associated performance.
Today, it is commonly agreed that mid-range rangefinders (typical range: 10 km) based on fiber laser
technology, constitute the best trade-off between performance and reliability. But to intend to compete with
long-range devices and propose an alternative to bulk solid state laser systems, it is essential to increase
significantly their extinction ratio (ER) compared to the state of the art.
In this paper, we report on successive real-time statistical algorithms performed on 2 different fiber laser
rangefinders and the feasability to achieve an extinction ratio up to 45dB in an eye-safety burst mode. Based
on a bi-static architecture and equipped with a 38 μJ and 125 μJ, 10 ns pulse fiber laser, their intrinsic ER in
single-pulse emission has been measured respectively at 28 and 33 dB. A 45 mm optical aperture receiver
and a specially designed compact electronics complete the device. This alternative to solid-states systems
dedicated to long range application, represents then a cost-effective solution.
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