scholarly journals Throughput scaling by spatial beam shaping and dynamic focusing

2021 ◽  
Author(s):  
Malte Kumkar ◽  
Myriam Kaiser ◽  
Jonas Kleiner ◽  
Daniel Flamm ◽  
Daniel Günther Grossmann ◽  
...  
Keyword(s):  
High Power ◽  
Ultrafast Lasers ◽  
Process Development ◽  
Short Pulse ◽  
Processing Parameters ◽  
In Situ Stress ◽  
Beam Shaping ◽  
Heat Accumulation ◽  
Transparent Materials

With availability of high power ultra short pulsed lasers, one prerequisite towards throughput scaling demanded for industrial ultrafast laser processing was recently achieved. We will present different scaling approaches for ultrafast machining, including raster and vector based concepts. The main attention is on beam shaping for enlarged, tailored processed volume per pulse. Some aspects on vector based machining using beam shaping are discussed. With engraving of steel and full thickness modification of transparent materials, two different approaches for throughput scaling by confined interaction volume, avoiding detrimental heat accumulation, are exemplified. In Contrast, welding of transparent materials based on nonlinear absorption benefits from ultra short pulse processing in heat accumulation regime. Results on in-situ stress birefringence microscopy demonstrate the complex interplay of processing parameters on heat accumulation. With respect to process development, the potential of in-in-situ diagnostics, extended to high power ultrafast lasers and diagnostics allowing for multi-scale resolution in space and time is addressed.

scholarly journals The challenges of productive materials processing with ultrafast lasers

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rudolf Weber ◽  
Thomas Graf
Keyword(s):  
Ultrafast Lasers ◽  
Average Power ◽  
Processing System ◽  
Processing Parameters ◽  
Materials Processing ◽  
High Tech ◽  
X Rays ◽  
Heat Accumulation ◽  
Physical Limitations ◽  
Air Breakdown

Abstract Materials processing with ultrafast lasers with pulse durations in the range between about 100 fs and 10 ps enable very promising and emerging high-tech applications. Moreover, the average power of such lasers is steadily increasing; multi kilowatt systems have been demonstrated in laboratories and will be ready for the market in the next few years, allowing a significantly increase in productivity. However, the implementation of ultrafast laser processes in applications is very challenging due to fundamental physical limitations. In this paper, the main limitations will be discussed. These include limitations resulting from the physical material properties such as the ablation depth and the optimal fluence, from processing parameters such as air-breakdown and heat accumulation, from the processing system such as thermal focus shift, and from legal regulations due to the potential emission of soft X-rays.

Ultrafast Laser Applications in Manufacturing Processes: A State-of-the-Art Review

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Shuting Lei ◽  
Xin Zhao ◽  
Xiaoming Yu ◽  
Anming Hu ◽  
Sinisa Vukelic ◽  
...  
Keyword(s):  
Ultrafast Lasers ◽  
Process Development ◽  
Short Pulse ◽  
Industrial Applications ◽  
Ultrafast Laser ◽  
Future Research ◽  
Manufacturing Processes ◽  
Laser Applications ◽  
Short Pulse Duration ◽  
Process Innovations

Abstract With the invention of chirped pulse amplification for lasers in the mid-1980s, high power ultrafast lasers entered into the world as a disruptive tool, with potential impact on a broad range of application areas. Since then, ultrafast lasers have revolutionized laser–matter interaction and unleashed their potential applications in manufacturing processes. With unprecedented short pulse duration and high laser intensity, focused optical energy can be delivered to precisely define material locations on a time scale much faster than thermal diffusion to the surrounding area. This unique characteristic has fundamentally changed the way laser interacts with matter and enabled numerous manufacturing innovations over the past few decades. In this paper, an overview of ultrafast laser technology with an emphasis on femtosecond laser is provided first, including its development, type, working principle, and characteristics. Then, ultrafast laser applications in manufacturing processes are reviewed, with a focus on micro/nanomachining, surface structuring, thin film scribing, machining in bulk of materials, additive manufacturing, bio manufacturing, super high resolution machining, and numerical simulation. Both fundamental studies and process development are covered in this review. Insights gained on ultrafast laser interaction with matter through both theoretical and numerical researches are summarized. Manufacturing process innovations targeting various application areas are described. Industrial applications of ultrafast laser-based manufacturing processes are illustrated. Finally, future research directions in ultrafast laser-based manufacturing processes are discussed.

Ultrafast Laser Applications in Manufacturing Processes: A State of the Art Review

2019 ◽  
Author(s):  
Shuting Lei ◽  
Xin Zhao ◽  
Xiaoming Yu ◽  
Anming Hu ◽  
Sinisa Vukelic ◽  
...  
Keyword(s):  
Ultrafast Lasers ◽  
Process Development ◽  
Short Pulse ◽  
Industrial Applications ◽  
Ultrafast Laser ◽  
Future Research ◽  
Manufacturing Processes ◽  
Laser Applications ◽  
Short Pulse Duration ◽  
Process Innovations

Abstract With the invention of chirped pulse amplification for lasers in the mid-1980s, high power ultrafast lasers entered into the world as a disruptive tool, with potential impact on a broad range of application areas. Since then, ultrafast lasers have revolutionized laser-matter interaction and unleashed their potential applications in manufacturing processes. With unprecedented short pulse duration and high laser intensity, focused optical energy can be delivered to precisely defined material locations on a time scale much faster than thermal diffusion to the surrounding area. This unique characteristic has fundamentally changed the way laser interacts with matter and enabled numerous manufacturing innovations over the past few decades. In this paper, an overview of ultrafast laser technology with an emphasis on femtosecond laser is provided first, including its development, type, working principle, and characteristics. Then ultrafast laser applications in manufacturing processes are reviewed, with a focus on micro/nano machining, surface structuring, thin film scribing, machining in bulk of materials, additive manufacturing, bio manufacturing, super high resolution machining, and numerical simulation. Both fundamental studies and process development are covered in this review. Insights gained on ultrafast laser interaction with matter through both theoretical and numerical research are summarized. Manufacturing process innovations targeting various application areas are described. Industrial applications of ultrafast laser based manufacturing processes are illustrated. Finally, future research directions in ultrafast laser based manufacturing processes are discussed.

A geometallurgical characterization study of the Crystalkop Reef at the Great Noligwa Mine, Klerksdorp Goldfield, South Africa

2017 ◽  
Vol 120 (3) ◽  
pp. 303-322
Author(s):  
D. Pienaar ◽  
B.M. Guy ◽  
C. Pienaar ◽  
K.S. Viljoen
Keyword(s):  
South Africa ◽  
Treatment Plant ◽  
Processing Parameters ◽  
Processing Plant ◽  
Small Contribution ◽  
Gold Cyanide ◽  
Three Samples ◽  
Characterization Study ◽  
Different Sources

Abstract Mineralogical and textural variability of ores from different sources commonly leads to processing inefficiencies, particularly when a processing plant is designed to treat ore from a single source (i.e. ore of a relatively uniform composition). The bulk of the Witwatersrand ore in the Klerksdorp goldfield, processed at the AngloGold Ashanti Great Noligwa treatment plant, is derived from the Vaal Reef (>90%), with a comparatively small contribution obtained from the Crystalkop Reef (or C-Reef). Despite the uneven contribution, it is of critical importance to ensure that the processing parameters are optimized for the treatment of both the Vaal and C-Reefs. This paper serves to document the results of a geometallurgical study of the C-Reef at the Great Noligwa gold mine in the Klerksdorp goldfield of South Africa, with the primary aim of assessing the suitability of the processing parameters that are in use at the Great Noligwa plant. The paper also draws comparisons between the C-Reef and the Vaal Reef A-facies (Vaal Reef) and attempts to explain minor differences in the recovery of gold and uranium from these two sources. Three samples of the C-Reef were collected in-situ from the underground operations at Great Noligwa mine for mineralogical analyses and metallurgical tests. Laboratory-scale leach tests for gold (cyanide) and uranium (sulphuric acid) were carried out using dissolution conditions similar to that in use at the Great Noligwa plant, followed by further diagnostic leaching in the case of gold. The gold in the ore was found to be readily leachable with recoveries ranging from 95% to 97% (as opposed to 89% to 93% for the Vaal Reef). Additional recoveries were achieved in the presence of excess cyanide (96% to 98%). The recovery of uranium varied between 72% and 76% (as opposed to 30% to 64% for the Vaal Reef), which is substantially higher than predicted, given the amount of brannerite in the ore, which is generally regarded as refractory. Thus, the higher uranium recoveries from the C-Reef imply that a proportion of the uranium was recovered by the partial dissolution of brannerite. As the Vaal Reef contain high amounts of chlorite (3% to 8%), which is an important acid consumer, it is considered likely that this could have reduced the effectiveness of the H2SO4 leach in the case of the ore of the Vaal Reef. Since the gold and uranium recoveries from the C-Reef were higher than the recoveries from the Vaal Reef, the results demonstrate that the processing parameters used for treatment of the Vaal Reef are equally suited to the treatment of the C-Reef. Moreover, small processing modifications, such as increased milling and leach retention times, may well increase the recovery of gold (particularly when e.g. coarse gold, or unexposed gold, is present).

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