Enhanced processing speed in laser drilling of stainless steel by spatially and temporally superposed pulsed Nd:YAG laser radiation

Walther, K.; Brajdic, Mihael; Kreutz, E. W.

doi:10.1007/s00170-006-0768-z

Cited by 50 publications

(8 citation statements)

References 16 publications

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“…This excellent beam quality allows a focus spot size 45 μm in diameter, producing a power density of 220 MW/cm 2 , as compared with M 2 = 22-38, 600 μm spot size, and approximately 3 MW/cm 2 for the laser used in Low and Li (2002) and Voisey et al (2002). Walther et al (2008) also utilized a diode-pumped solid state (DPSS) Nd:YAG laser (Powergator 1064, Lambda Physik) which has a beam quality of M 2 = 1.7, with a spot size of 42 μm, 17 ns pulse, and 1.8 mJ pulse energy, producing a power density over 20 GW/cm 2 .…”

Section: Review Of Short Microsecond Pulse Drillingmentioning

confidence: 99%

“…Kreutz et al (2007) applied this drilling technique to drill cooling holes in turbine components with multiple pulses (percussion drilling) combined with oxygen, helium, and argon assist gasses. Walther et al (2008) combined the above Nd:YAG slab laser and the DPSS Nd:YAG laser to achieve very high aspect ratio percussion drilling (5 mm through holes with 170-180 μm waist diameter). Walther et al (2008) utilized a flash lamp pumped Nd:YAG slab laser (FM015, LASAG) with a beam quality as M 2 = 2 and it can produce pulses with durations from 100 to 500 μs and a laser energy of 0.64 J.…”

Section: Review Of Short Microsecond Pulse Drillingmentioning

confidence: 99%

“…Walther et al (2008) combined the above Nd:YAG slab laser and the DPSS Nd:YAG laser to achieve very high aspect ratio percussion drilling (5 mm through holes with 170-180 μm waist diameter). Walther et al (2008) utilized a flash lamp pumped Nd:YAG slab laser (FM015, LASAG) with a beam quality as M 2 = 2 and it can produce pulses with durations from 100 to 500 μs and a laser energy of 0.64 J. This excellent beam quality allows a focus spot size 45 μm in diameter, producing a power density of 220 MW/cm 2 , as compared with M 2 = 22-38, 600 μm spot size, and approximately 3 MW/cm 2 for the laser used in Low and Li (2002) and Voisey et al (2002).…”

Section: Review Of Short Microsecond Pulse Drillingmentioning

confidence: 99%

See 2 more Smart Citations

Process Anatomy for High Aspect Ratio Micro-Hole Drilling with Short Micro-Second Pulses Using a CW Single-Mode Fiber

Tu¹,

Lehman²,

Paleocrassas³

et al. 2013

APR

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The objective of this paper is to establish a detailed process anatomy of a micro-hole drilling process using a CW single-mode 300 W fiber laser with short micro-second pulses. For the drilling process with a one micro-second laser pulse, the process started with drastic evaporation and concluded with melt ejection approximately 150 micro-seconds later. It was concluded that two distinct hole drilling mechanisms occurred, one as adiabatic evaporation by the high power initial spike of the laser beam and one as melt ejection by the low power laser energy deposition. The drilling process time line was established based on the measurements by several in-process sensors, such as photodiodes, a high-speed camera, and a spectrometer. The theoretical modeling zoomed in the early stage of the process to investigate the hole formation which could not be observed experimentally. Both experimental and theoretical results were then compared to determine the laser-material interaction mechanisms among three media involved in the process: laser, material, and vapour/plasma. Finally, a series of temporal anatomy diagrams, denoted as process anatomy, were presented to describe the entire drilling process, including process temperature, laser energy deposition, hole formation, and material removal mechanisms.

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Section: Review Of Short Microsecond Pulse Drillingmentioning

confidence: 99%

Section: Review Of Short Microsecond Pulse Drillingmentioning

confidence: 99%

Section: Review Of Short Microsecond Pulse Drillingmentioning

confidence: 99%

See 1 more Smart Citation

Process Anatomy for High Aspect Ratio Micro-Hole Drilling with Short Micro-Second Pulses Using a CW Single-Mode Fiber

Tu¹,

Lehman²,

Paleocrassas³

et al. 2013

APR

View full text Add to dashboard Cite

show abstract

“…[9][10][11][12][13][14][15][16][17][18][19][20][21] Micro structuring experiments were performed at a repetition rate = 250 kHz. The pulses per burst were changed between n = 1 and 4 pulses with a inter pulse separation of 20 ns within the burst (Fig.…”

Section: Mirror Axismentioning

confidence: 99%

Nano Structured Physical Vapor Deposited Coatings by Means of Picosecond Laser Radiation

Bobzin¹,

Bagcivan²,

Ewering³

et al. 2011

J. Nanosci. Nanotech.

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Molding of nano structures by injection molding leads to special requirements for the tools e.g., wear resistance and as low as possible release forces of the molded components. On the other hand it is not allowed to affect the replication precision. Physical vapor deposition is one of the promising technologies for applying coatings with adapted properties like high hardness, low roughness, low Young's modulus and less adhesion to the plastics melt. Although physical vapor deposition technology allows the deposition of films on micro structures without changing the structure significantly, film deposition on nano structures and small micro structures leads to a relevant change in surface topography. For this reason direct structuring of physical vapor deposition coatings might be beneficial. In this paper structuring was done using a picoseconds ultraviolet laser, Lumera Laser "Rapid," with a master oscillator power amplifier system at 355 nm. Two different coatings were deposited by magnetron sputter ion plating physical vapor deposition technology for laser structuring tests ((Cr, Al)N, (Cr, Al,Si)N). After deposition, the coatings were analyzed by common techniques regarding hardness, Young's modulus and morphology. The structures were analyzed by scanning electron microscopy. The results show a high potential for laser structuring of coatings deposited via physical vapor deposition. Linear structures with sizes between 400 nm and 10microm were realized.

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“…Fox found a decrease of irradiation time by more than a factor of two in addition to the increase in the quality as using CW only. Other DLM experiments have demonstrated improvements in laser drilling material removal rates in stainless steel by up to an order of magnitude [24][25][26]. However, there is a considerable range of results both in quality and efficiency.…”

Section: Introductionmentioning

confidence: 99%

Increasing the efficiency of material removal using dual laser micromachining

Alkhawaldeh

Coupland

Jones

2020

Int J Adv Manuf Technol

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A continuous wave melting laser combined with a nanosecond ejection laser has been shown to improve the material removal efficiency by a factor of 2 to 8 compared with laser ablation processes reported in the literature. The decrease in the energy required for the combined lasers is primarily due to the optimisation of the irradiation time in the melting process, which is responsible for the majority of the total energy. For the laser used in this study, the optimal interaction time corresponding to the highest melting efficiency was found at 9-ms melting time, and this value is compared with results derived from a onedimensional heating model. Metallurgical images of only melting and the produced hole after introducing the ejection pulse for the most efficient melting were presented as evidence of melt ejection. The results show that approximately 90% of the melt pool is ejected with little redeposited material at the periphery of the hole.

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Enhanced processing speed in laser drilling of stainless steel by spatially and temporally superposed pulsed Nd:YAG laser radiation

Cited by 50 publications

References 16 publications

Process Anatomy for High Aspect Ratio Micro-Hole Drilling with Short Micro-Second Pulses Using a CW Single-Mode Fiber

Process Anatomy for High Aspect Ratio Micro-Hole Drilling with Short Micro-Second Pulses Using a CW Single-Mode Fiber

Nano Structured Physical Vapor Deposited Coatings by Means of Picosecond Laser Radiation

Increasing the efficiency of material removal using dual laser micromachining

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