United States

Ultra-short pulse laser machining has emerged as a transformative technology across various industries, including medical device fabrication, electronics manufacturing, and precision glass machining. With each technological leap in laser power, new industrial applications have become feasible. Yet, as the industry approaches the threshold of high-power ultra-short pulse lasers, such as kilowatt-scale femtosecond systems for advanced R&amp;D, the challenge shifts from merely harnessing this power to utilizing it intelligently without sacrificing machining quality. This is crucial as many users currently underutilize their systems&#39; capabilities due to quality degradation at higher power settings.

This presentation addresses the utilization of Multi-Plane Light Conversion (MPLC) technology to optimize and expand the capabilities of ultra-short pulse laser systems. MPLC technology, notable for its entirely reflective design, ensures durability under high power and enhances process efficiency. Its mode-cleaning feature provides stable and robust beam shaping, which is less susceptible to laser and environmental variations, making it ideal for precision applications. Additionally, MPLC allows for intricate, high-quality beam shaping with an extensive depth of field, significantly easing integration into existing systems.

We will discuss the application of MPLC in combining beam shaping with splitting functionalities, highlighting the flexibility of this approach. Specific adaptations, such as adjustable beam division pitch, shape alterations, and rotation capabilities, will be showcased alongside their impact on the quality of micro-machining processes, particularly in surface texturing. The results underscore substantial improvements in both the quality and throughput of machining processes.

ICALEO 2024

Advancing Ultra-Short Pulse Laser Machining with MPLC Technology: Enhancing Micro-Processing Capabilities

micro-processing

beam-shaping

Ultra-short pulse laser machining has emerged as a transformative technology across various industries, including medical device fabrication, electronics manufacturing, and precision glass machining. With each technological leap in laser power, new industrial applications have become feasible. Yet, as the industry approaches the threshold of high-power ultra-short pulse lasers, such as kilowatt-scale femtosecond systems for advanced R&D, the challenge shifts from merely harnessing this power to utilizing it intelligently without sacrificing machining quality. This is crucial as many users currently underutilize their systems' capabilities due to quality degradation at higher power settings.

This presentation addresses the utilization of Multi-Plane Light Conversion (MPLC) technology to optimize and expand the capabilities of ultra-short pulse laser systems. MPLC technology, notable for its entirely reflective design, ensures durability under high power and enhances process efficiency. Its mode-cleaning feature provides stable and robust beam shaping, which is less susceptible to laser and environmental variations, making it ideal for precision applications. Additionally, MPLC allows for intricate, high-quality beam shaping with an extensive depth of field, significantly easing integration into existing systems.

We will discuss the application of MPLC in combining beam shaping with splitting functionalities, highlighting the flexibility of this approach. Specific adaptations, such as adjustable beam division pitch, shape alterations, and rotation capabilities, will be showcased alongside their impact on the quality of micro-machining processes, particularly in surface texturing. The results underscore substantial improvements in both the quality and throughput of machining processes.

technical paper

  #### Welcome to the 43rd annual ICALEO!

Attention laser enthusiasts, innovators, and industry leaders! Get ready to immerse yourself in the exciting world of lasers at the 43rd annual ICALEO conference. This year, we gathered in the iconic city of Hollywood, California, for cutting-edge technology, groundbreaking presentations, and unparalleled networking opportunities.
Whether you're a seasoned professional or new to the field of photonics, the 43rd annual ICALEO had something for everyone. 

#### General Chair Welcome Message

It is with immense joy and anticipation that I extend a warm welcome to each and every one of you as the General Chair of this year's ICALEO conference.

This year, we find ourselves in the iconic setting of Hollywood, serving as a fitting backdrop for the extraordinary developments in laser technology and applications unfolding in our community.

Our main sessions cover a diverse range of topics, from the intricacies of micro and nano processing to the transformative power of laser additive manufacturing. We will explore the frontiers of battery technology, delve into the intricate world of artificial intelligence, and witness the seamless integration of lasers into these realms.

For those joining us for the first time, we extend an especially heartfelt welcome. ICALEO is not just a conference; it's a convergence of minds, ideas, and innovations. Beyond the formal sessions, I encourage you to engage in informal exchanges. The spirit of discovery and camaraderie is as much a part of the ICALEO experience as the scheduled sessions.

Thank you for being a part of ICALEO 2024. Whether you are a returning participant or a first-time attendee, your presence adds immeasurable value to our vibrant community. May this conference be, this year again, a catalyst for inspiration, collaboration, and breakthroughs that will resonate in our community and beyond.

Eric Mottay<br>
Congress General Chair, ICALEO 2024


#### About LIA

The Laser Institute of America (LIA) is the professional society for laser applications and safety. Our mission is to foster lasers, laser applications, and laser safety worldwide. Serving the industrial, medical, research and government communities for over 50 years, LIA offers technical information, training and networking opportunities to laser users
from around the globe.

#### About LIA Conferences

The conferences of the Laser Institute of America are the town square of the laser community. A large and diverse group, laser professionals often find themselves disconnected from each other. LIA conferences, however, bring the university researcher, the business executive and the production floor user together under one roof for a unique and
rewarding networking opportunity.

#### Program Tracks
Below is the list of all tracks that were on ICALEO 2024 Conference.

##### Laser Additive Manufacturing
* The Laser Additive Manufacturing (LAM) track is a forum to explore the latest innovations and research in laser-based additive manufacturing (LAM). The Laser Additive Manufacturing track focuses on diverse topics, including laser-based powder bed fusion (PBF-LB), directed energy deposition (DED), and other emerging techniques revolutionizing modern manufacturing processes. From materials science to process optimization, from design innovation to industrial implementation, this track connects researchers, engineers, and industry leaders to exchange insights and share breakthroughs in laser additive manufacturing.

##### Laser Materials Macroprocessing
* The Macroprocessing track comprises some of the most productive laser processing applications. Although these applications have been broadly adopted, researchers and industry are persistently innovating to provide new techniques and novel technologies to advance macro materials processing. The attendees will share and discuss those exciting achievements of their research with peers in these macroscopic specialized sessions.

##### Laser Materials Microprocessing
* The Microprocessing track will consist of papers and talks featuring a wide spectrum of applications and innovative equipment for materials processing in microscales with a strong focus on processes with Short and Ultrashort Pulsed Lasers. The presentations will introduce the latest and greatest advancements in their respective fields, presented by world-leading companies and research organizations. This year we will have talks around the headlines of “Beam shaping”, “Glass”, “Surface processing” and “Drilling” between other topics.

##### Frontiers in Laser Applications
* The Frontier in Laser Applications (FLA) track explores recent, cutting-edge applications of lasers, highlighting innovation at the transition of research and industry. The track has included presentations from a variety of fields: Novel 3-D Printing, Advanced Manufacturing, Laser Manufactured Devices, and Frontiers in Laser Processing. The sessions under the Frontier in Laser Application track promise to bring diverse and unique perspectives from real-world applications across laser manufacturing.

##### Laser in Battery Manufacturing
* Electrification is crucial to address global environmental challenges. The laser plays a key role in most manufacturing steps in battery production with all possible laser applications from ablation, structuring, welding, cutting, and marking. Further improvements in the batteries’ power densities, fast charging properties, and yield in battery production are related to photonics and, thus, lasers. We will hear and discuss the latest developments in research, development, and industrial applications. Join us for this year’s Battery Track.

##### Artifical Intelligence in Laser Processing
* The track ‘Artificial Intelligence in Laser Processing’ at ICALEO 2024 explores the fusion of AI and laser manufacturing. Discover cutting-edge research on optimizing laser processes and enhancing manufacturing efficiency. Explore AI’s diverse applications in parameter optimization, quality prediction, real-time process monitoring, and control. Join us to unlock the potential of AI-driven solutions revolutionizing laser materials processing, delivering unprecedented precision, productivity, and innovation.
<br><br>


To access the site please register [**here**](https://icaleo.org/attend). 

Are you an LIA Member? Find a special discount code in your LIA account at https://www.lia.org/user to apply to your registration for additional savings!

Please register for the ICALEO 2024 Conference to join the event.

Attention laser enthusiasts, innovators, and industry leaders! Get ready to immerse yourself in the exciting world of lasers at the 43rd annual ICALEO conference. 

Laser metal deposition (LMD) is already established in industry for cladding and additive manufacturing in various fields. This presentation is designed to provide a comprehensive examination of laser cladding and additive manufacturing, two critical methodologies in the field of advanced manufacturing. The primary objective is to juxtapose the utilization of wire and powder as feedstock materials in these processes.

Initially, we will explain the fundamental principles, applications, and advantages of laser cladding and additive manufacturing with multi kW diode lasers in the visible and near infrared spectrum. This foundational knowledge will facilitate a thorough investigation of the wire-fed and powder-fed techniques, underscoring their respective merits and challenges.

Subsequently, the presentation will delve into the material properties, process parameters, and performance characteristics pertinent to each technique. We will analyze the impact of these variables on the quality of the final product, encompassing facets such as surface finish, dimensional accuracy, and mechanical properties.

Through a series of case studies, we will demonstrate the practical implications of selecting wire or powder as well as the proper laser source with optical combination in diverse manufacturing scenarios. The presentation will culminate with a discourse on the future trends in laser cladding and additive manufacturing, emphasizing the potential of these techniques in revolutionizing the manufacturing industry.

This presentation invites attendees to explore this captivating domain illuminating the crucial role of wire and powder techniques in shaping the future of manufacturing and empowering them with the knowledge to make informed equipment decisions

An In-depth Comparative Analysis of Wire and Powder Techniques in Laser Cladding and Additive Manufacturing

Simultaneous Machining and Coating (SMaC) is a novel hybrid technology developed by the Fraunhofer Institute for Laser Technology ILT that combines additive manufacturing through Extreme High-speed Laser Material Deposition (EHLA) with a simultaneously engaged turning process. In the present work, the parallelization of the two sub-processes is successfully demonstrated. For the first time, systematic investigations into the influence of residual heat from the deposition process on the machining process, respectively the properties of the resulting coating are conducted. The study specifically examines geometric deviations, surface roughness, and tool wear. One of the main parameters affecting the residual heat introduced into the turning process, is the distance between the tool center points of the EHLA deposition head and the turning tool Δz. This parameter is identified as a primary factor influencing the dimensional accuracy of the coating geometry. The results show that SMaC not only offers potential for increasing the productivity of the process chain, but also has a positive effect on the service life of the cutting tools involved, potentially improving the workability of hard coating materials. Improvements in terms of the attainable surface roughness are also observed. The investigations provide a basis for research into further aspects of the SMaC process, such as adaptive tool path control methods to enhance dimensional accuracy and the influence of induced compressive stresses on processing highly brittle coating materials.

Fundamentals of Simultaneous Machining and Coating (SMaC) through Combination of Extreme High-speed Laser Material Deposition (EHLA) and Turning

As electric car age, BEV batteries are increasingly being disassembled at EOL of battery cells. In general, it can be stated that their design has not considered the disassembly of batteries in the best possible way, thinking about secondary use or efficient recycling. This paper has collected tested methods found in the literature or laser processes in use for dismantling battery packs, especially for the second life use of battery cells. The research has created a concept for the Metaverse environment, where the safety aspects that can be achieved in laser processing could be studied when the system is controlled by remote control. In addition, a case has been presented as an example of the suitability of laser brazing in a collaborative robot and handheld laser process for automatic production. The experiment uses aluminum printed battery cell components and sheet metal busbar parts to demonstrate the electrical and mechanical properties of the joint. The disassembly of busbar parts was demonstrated in the Metaverse environment using the laser machining method, which automatically disassembles the connection using the Metaverse environment, especially considering laser safety. In the study, functional solutions have been sought from the point of view of automatic disassembly of the laser brazing joint by using the Metaverse environment.

Review of Current State of Technologies Enabling Circular Economy in Vehicle Batteries and a Role of Laser Processing and Remote Operation via Metaverse

The structuring of lithium-ion battery (LIB) electrodes and the diffusion media (DM) for polymer electrolyte membrane fuel cells (PEMFCs) with ultrashort laser pulses enables improved performance characteristics of both technologies. However, the transfer of the approaches from a laboratory scale to a commercial use has previously been hindered by the low average output power of ultrashort-pulsed (USP) laser beam sources and the limited productivity of single beam structuring using scanning optics. Recent advancements in the development of USP laser systems have led to a steady increase in the available output power, thereby enabling new fields of applications. This study aims at accelerating the USP laser structuring of LIB electrodes and DM for PEMFCs to industrially relevant processing rates by comparing a single-beam with a multi-beam structuring process regarding ablation characteristics and quality. For the multi-beam strategy, the shape of the laser beam was modified by a spatial light modulator (SLM). In addition to micro-holes, the insertion of micro-channels was investigated to demonstrate the high flexibility of state-of-the-art SLMs. The geometry of the created structures was measured with a laser scanning microscope, and the different layers were tested for their geometrical and electrochemical properties to compare both technologies. The results confirmed that applying an SLM enables high-quality microstructures with significantly higher structuring rates. Furthermore, this contribution includes a theoretical analysis of the specifications required for a laser setup to reach an industrially relevant productivity of the structuring processes.

Scaling of Ultrashort-Pulsed Laser Structuring Processes for Electromobility Applications Using a Spatial Light Modulator

In recent years, there has been an increased demand for elaborate monitoring techniques in laser material processing. This has been driven by the need for fast and cost-efficient quality assurance processes. At the same time, the use of ultrashort-pulsed (USP) laser radiation has emerged as a promising technology for creating intricate microstructures in graphite anodes due to their high precision and the negligible thermal impact. However, the integration of process monitoring in USP applications for graphite anode structuring is still underexplored. There is a lack of clarity on suitable sensors, observable parameters, and extractable process-relevant insights. This study addresses this gap by demonstrating the efficacy of state-of-the-art photodiode-based monitoring systems in collecting process-relevant data and deriving valuable insights from the process. As an application case, the laser structuring of lithium battery electrodes, consisting of a porous, graphite-based, and multi-material system was selected. A sensor equipped with three photodiodes was employed to address these challenges. Exploratory data analysis techniques and machine learning methodologies were leveraged to develop a data pipeline for processing the acquired information. The data was used to train convolutional neural networks which were able to predicting the focal position with high accuracy. At the same time, the limitations of traditional regression approaches could be shown. The findings advance the understanding of the possibilities of process monitoring in USP laser applications and emphasize the significance of data-driven approaches in optimizing manufacturing processes.

Photodiode-Based Focus Monitoring in Ultrashort-Pulsed Laser Structuring of Graphite Anodes for Lithium-Ion Batteries

The artificial intelligence approach in the monitoring of laser welding is widely studied to ensure the good weld quality. In this study, a deep neural network (DNN)-based monitoring framework for weld shape prediction was established. This weld shape prediction model takes an optical signal as its input and generates a weld shape image as its output. Optical signals were acquired using the optical emission spectroscopy (OES). For the training of prediction model, this acquired optical signal was preprocessed using three methods: principal component analysis (PCA), spectral feature extraction (SFE), and relative intensity calculation (RIC). The weld shape image used for model training was generated by obtaining an eigen-image using the singular value decomposition (SVD) method. Supervised learning was used, and the generated images were labeled with optical signals according to the process conditions. Model evaluation was performed by comparing the weld area in the eigen-images with the one in predicted images. The two weld images were completely overlapped using feature points (e.g., top surface or tip of welds), and then, image accuracy was quantitatively determined by dividing the intersection area of these images by their union area. The weld shape predicted by the DNN model showed the accuracy of ~90% for all input data types.

DNN-Based Real-Time Monitoring of Weld Shape during the Laser Welding Process

Event cameras differ from conventional frame cameras: Rather than capturing images at a fixed rate, they asynchronously measure pixelwise brightness changes, and stream an event sequence that includes time, location and sign of the brightness changes. Event cameras provide attractive properties like high temporal resolution and latency (both in the order of ms), very high dynamic range (120 dB) and low power consumptions because no routine operation needs to be recorded. Hence, event cameras have been successfully used for instance for object tracking, pose estimation, or image deblurring. Due to the described advantages of event cameras compared to these sensors, this paper for the first time, investigates the potential of event cameras in laser welding. One of the key questions of event cameras is how to extract meaningful information from the event data for in-process monitoring. Therefore, we present different promising ways to process the unconventional asynchronous output of event cameras for process monitoring, including time-series representations such as event rates, as well as image representations such as projections on the xy-plane of the event camera view field or projections along the scanner path.

Our laser welding experiments show clear differences for different production scenarios in those event representations. Additionally, we propose a machine learning pipeline for the automatic detection of production errors with event camera.

Event-Based Vision in Laser Welding: An Approach for Process Monitoring

In laser welding, precision and reproducibility are fundamentally dependent on temporal and spatial processes of energy input. Induced by the dynamics of the melt pool, pressure equilibria in the vapor capillary, and solidification behavior, different weld seam qualities are achieved. To obtain the lowest possible defect frequency, new tailored joining strategies need to be investigated using multibeam and multiwavelength approaches. To improve the quality by influencing the process dynamics, a dual-beam approach is investigated that superimposes a stationary laser beam with a wavelength of 445 nm with a spatially modulated laser beam with a wavelength of 1070 nm. The aim is to utilize ∼10 times higher absorption of a 445 nm diode laser on copper with the high focusability of a 1070 nm fiber laser. In this context, the influence of the relative positions of the two beams to each other on the weld seam quality is investigated, while one of the beams moves either in front, behind, or coaxial to the other beam following the path of a line weld. The main objective is to observe how the laser beams influence each other and how the capillary depth and porosity vary for different parameters. To visualize the process dynamics, the welding experiments on copper are performed at the Deutsches Elektronen-Synchrotron DESY by means of in situ phase contrast videography. Quality-determining weld properties like the distribution of pores or process fluctuations are then extracted automatically from the image sequences by means of a trained neuronal network.

Analysis of Laser Beam Welding with Superimposed 445 nm and 1070 nm Wavelength Lasers on Copper by In situ Synchrotron Diagnostics

Laser beam shaping is an important tool for laser welding applications, particularly in battery welding where many combinations of materials, requirements and conditions can be present for production of a single unit. The ability to change intensity profile “on-the-fly”, without equipment changes, widens the processing window available to a single welding tool. Here we present a straightforward method for variable beam shaping, using freeform refractive optical elements in combination with conventional optical elements and systems.



PowerPhotonic’s manufacturing process is truly freeform, with no restrictions on rotational, translational or mirror symmetry. With this freedom, beam shaping elements can be designed to produce different output intensity profiles depending on the variation of another system parameter, such as input beam size, optic rotation or alignment. This allows optical power to be moved between different parts of an output profile with simple mechanical motion in the optical train. For example, translation of a single optic can result in adjustment of power between a central spot and a surrounding annulus.



In addition, freeform surfaces allow a wide variety of output profiles to be considered in the design, beyond the conventional Gaussians, flat-tops and rings. The flexibility in target intensity profiles combined with in-situ adjustability gives significant additional degrees of freedom for laser welding applications.

Variable Beam Shaping for Battery Welding Enabled by Freeform Optics

The advent of laser metal additive manufacturing (LMAM) unlocked a new phase in materials development and fabrication, where physical phenomenon in the melt-pool and Marangoni convection enables finer control of the material microstructure and physical properties. While these advantages make LMAM very attractive, there are various drawbacks to using metallic 'loose' powder  such as health hazards, difficulty in switching materials and recyclability. An approach to mitigate some of these disadvantages is the innovation of a novel polymer-metal composite, where metal powder is tightly packed with a polymer binder. This novel feedstock is produced via solvent casting, and sintered layer-by-layer similar to traditional LMAM process. Recent research has proved great potential in this approach, delivering promising efficiencies in LMAM and enhanced material characteristics in materials such as 304SS and high-entropy-alloys. This work will show how the selection of polymer binder can produce materials with a range of mechanical properties. Work will also be presented on a novel laser debinding approach using the polymer-metal composite. This work will cover a thorough investigation utilizing in-situ melt pool analysis combined with microstructural EBSD and XRD. In addition to increasing manufacturing efficiencies, this innovation has the potential to produce functionally gradient parts and enhanced coatings without the requirement of 'loose powder'.

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Advancing Ultra-Short Pulse Laser Machining with MPLC Technology: Enhancing Micro-Processing Capabilities

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An In-depth Comparative Analysis of Wire and Powder Techniques in Laser Cladding and Additive Manufacturing

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