Acoustic and Optical Monitoring of High-Power CO2 Laser Cutting

2007 ◽  
Vol 344 ◽  
pp. 161-168 ◽  
Author(s):  
Johan De Keuster ◽  
Joost R. Duflou ◽  
Jean Pierre Kruth
Keyword(s):  
High Power ◽  
Laser Cutting ◽  
Quality Parameters ◽  
Steel Plates ◽  
Cut Edge ◽  
Edge Roughness ◽  
Cut Quality ◽  
Dross Formation ◽  
Photodiode Signal ◽  
Thick Steel

In this paper, the development of a monitoring system for high-power CO2 laser cutting of thick steel plates (>15 mm) is reported. The aim of this system is to increase the robustness and autonomy of the laser cutting process of thick plates, which is still characterized by more narrow process windows compared to cutting of thin sheets. The applicability for monitoring purposes of two types of sensors is investigated: the acoustic microphone and the photodiode. For both types, correlation between the sensor output and the cut quality is investigated. Both contour cutting and piercing are covered in the study. The full penetration of the piercing can be monitored by both sensors. Furthermore quantitative relations between cut quality parameters and photodiode signal parameters could be determined: the mean level of the photodiode signal correlates well with the drag of the striations and dross formation, whereas the standard deviation proves to correlate well with the occurrence of burning defects and the cut edge roughness.

Laser forming of thick steel plates with a high power diode laser

2001 ◽  
Author(s):  
Abe Nobuyuki ◽  
Nakagawa Naoki ◽  
Tsukamoto Masahiro ◽  
Nakacho Keiji ◽  
Sogabe Michihiro ◽  
...  
Keyword(s):  
Diode Laser ◽  
High Power ◽  
Steel Plates ◽  
Laser Forming ◽  
Thick Steel ◽  
Power Diode ◽  
High Power Diode Laser

Improvement of cutting performance for thick stainless steel plates by step-like cutting speed increase in high-power fiber laser cutting

2018 ◽  
Vol 103 ◽  
pp. 311-317 ◽  
Author(s):  
Sangwoo Seon ◽  
Jae Sung Shin ◽  
Seong Yong Oh ◽  
Hyunmin Park ◽  
Chin-Man Chung ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Fiber Laser ◽  
High Power ◽  
Laser Cutting ◽  
Cutting Speed ◽  
Cutting Performance ◽  
Steel Plates ◽  
Speed Increase

Effect of Laser Beam Diameter on Cut Edge of Steel Plates Obtained by Laser Machining

2013 ◽  
Vol 467 ◽  
pp. 227-232 ◽  
Author(s):  
Imed Miraoui ◽  
Mouna Zaied ◽  
Mohamed Boujelbene
Keyword(s):  
Laser Beam ◽  
Laser Cutting ◽  
Steel Plates ◽  
Beam Diameter ◽  
Power Laser ◽  
Laser Beam Diameter ◽  
Machined Surface ◽  
Cut Edge ◽  
Thermal Influence ◽  
Cut Surface

Laser cutting is a thermal process which is used contactless to separate materials. In the present study, high-power laser cutting of steel plates is considered and the thermal influence of laser cutting on the cut edges is examined. The microstructure and the microhardness of the cut edge are affected by the input laser cutting parameter: laser beam diameter. The aim of this work is to investigate the effect of the laser beam diameter on the microhardness beneath the cut surface of steel plates obtained by CO2 laser cutting. The cut surface was studied based on microhardness depth profiles beneath the machined surface. The results show that laser cutting has a thermal effect on the surface microstructure and on the microhardness beneath the cut section. Also the microhardness of the hardening zone depends on the laser beam diameter.

Analysis of process efficiency in laser fusion cutting and some single- and multi-objective optimization aspects

2021 ◽  
pp. 095440892110627
Author(s):  
Miloš Madić ◽  
Mohamed H Gadallah ◽  
Dušan Petković
Keyword(s):  
Laser Power ◽  
Laser Cutting ◽  
Optimization Problem ◽  
Removal Rate ◽  
Cutting Speed ◽  
Process Efficiency ◽  
Laser Fusion ◽  
Cut Quality ◽  
Dross Formation ◽  
Laser Fusion Cutting

For an efficient use of laser cutting technology, it is of great importance to analyze the impact of process parameters on different performance indicators, such as cut quality criteria, productivity criteria, costs as well as environmental performance criteria (energy and resource efficiency). Having this in mind, this study presents the experimental results of CO2 laser fusion cutting of AISI 304 stainless steel using nitrogen, with the aim of developing a semi-empirical mathematical model for the estimation of process efficiency as an important indicator of the achievable energy transfer efficiency in the cutting process. The model was developed by relating the theoretical power needed to melt the volume per unit time and used laser power, where the change of kerf width was modeled using an empirical power model in terms of laser cutting parameters such as laser power, cutting speed, and focus position. The obtained results indicated the dominant effect of the focus position on the change in process efficiency, followed by the cutting speed and laser power. In addition, in order to maximize process efficiency and simultaneously ensure high cut quality without dross formation, a laser cutting optimization problem with constraints was formulated and solved. Also, a multi-objective optimization problem aimed at simultaneous optimization of process efficiency and material removal rate was formulated and solved, where the determined set of Pareto non-dominated solutions was analyzed by using the entropy method and multi-criteria decision analysis method, that is, the Technique for Order of Preference by Similarity to Ideal Solution. The optimization results revealed that in order to enhance process efficiency and material removal rate, while ensuring high cut quality without dross formation, focusing the laser beam deep into the bulk of material is needed with particular trade-offs between laser power and cutting speed levels at high pressure levels of nitrogen.

Laser cutting of thick steel plates and simulated steel components using a 30 kW fiber laser

2015 ◽  
Vol 53 (6) ◽  
pp. 916-920 ◽  
Author(s):  
Koji Tamura ◽  
Ryoya Ishigami ◽  
Ryuichiro Yamagishi
Keyword(s):  
Fiber Laser ◽  
Laser Cutting ◽  
Steel Plates ◽  
Thick Steel

Quality Analysis of Pulsed Laser Cutting of Superalloy Sheet

2006 ◽  
Vol 315-316 ◽  
pp. 113-117
Author(s):  
S.J. Lv ◽  
Yang Wang ◽  
Shi Jun Ji
Keyword(s):  
Laser Cutting ◽  
Cutting Speed ◽  
Pulsed Laser ◽  
Cutting Parameters ◽  
Recast Layer ◽  
Thin Layers ◽  
Quality Analysis ◽  
Quality Factors ◽  
Cut Quality ◽  
Dross Formation

This paper presents the experiments of Nd:YAG pulsed laser cutting of GH3536 superalloy sheet and investigates the influences of different cutting parameters on laser cut quality factors including recast layer, kerf width and dross formation. The results show that the recast layer possesses finer granularity and higher hardness than those of the matrix, and the thickness of recast layer increases with increased pulse energy and decreases as the cutting speed and gas pressure increase. Oxygen-assisted cutting comes with thick recast layers and argon-assisted cutting acquires thin layers. The low-strength oxide layer worsens the kerf surfaces in oxygen-assisted cutting while argon-assisted cutting produces unaffected surface quality and is suitable for applications with subsequent welding.

Off-Axial, Gas-Jet-Assisted, Laser Cutting of 6.35-mm Thick Stainless Steel

1995 ◽  
Vol 117 (2) ◽  
pp. 272-276 ◽  
Author(s):  
M. J. Hsu ◽  
P. A. Molian
Keyword(s):  
Stainless Steel ◽  
Laser Cutting ◽  
Gas Flow ◽  
Cutting Speed ◽  
Steel Plates ◽  
304 Stainless Steel ◽  
Gas Jet ◽  
Process Conditions ◽  
Cut Edge ◽  
Machining Rate

A dual gas-jet, laser-cutting technique involving coaxial and off-axial oxygen gas flows was developed to cut 6.35-mm thick AISI 304 stainless steel plates with a 1.2-kW CO2 gas transport laser at a cutting speed of 12.7 mm/sec (30 in./min). Under identical process conditions, the single, coaxial gas jet could not cut the stainless steel although the cutting speed was reduced to 2.11 mm/sec (5 in./min). Thresholds of off-axial nozzle diameter, gas-impinging angle, oxygen pressure, and other process parameters were determined to obtain clean-cut edge quality (average dross height 0.25 mm). Experimental data coupled with a fluid-dynamics model of gas flow were presented to show the effectiveness of the dual gas-jet, laser-cutting method in achieving the maximum machining rate without deteriorating the quality of cut.

scholarly journals Factorial Analysis of Fiber Laser Fusion Cutting of AISI 304 Stainless Steel: Evaluation of Effects on Process Performance, Kerf Geometry and Cut Edge Roughness

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2669
Author(s):  
Achim Mahrle ◽  
Madlen Borkmann ◽  
Peer Pfohl
Keyword(s):  
Stainless Steel ◽  
Focal Plane ◽  
Laser Power ◽  
Laser Cutting ◽  
304 Stainless Steel ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Cut Edge ◽  
Edge Roughness ◽  
Beam Oscillation

Factorial Design-of-Experiment analyses were applied for conventional and beam oscillation fiber laser cutting of 10 mm thick AISI 304 stainless steel. Considered factors in case of the conventional process with a static beam involve both laser and cutting gas parameters, in particular the laser power, the focal plane position, the cutting gas pressure, the nozzle stand-off distance as well as the nozzle diameter. The conducted trials were evaluated with respect to the achievable cutting speed, the cut kerf geometry and the cut edge roughness. Noticeable correlations between cut edge roughness and cut kerf geometry stimulated the development of a corresponding Computational Fluid Dynamics (CFD) model of the cutting gas flow through the kerf. A specific approach of data synchronization revealed that the experimentally determined roughness values do well correlate with numerically computed values of the backward directed component of the gas-induced shear stress and that the cut kerf geometry as internal process-inherent boundary condition influences relevant cutting characteristics more than controllable external cutting gas parameters. Finally, effects of circular beam oscillation were investigated by an additional factorial analysis considering the laser power, the focal plane position, the oscillation frequency and the oscillation amplitude as factors. The results demonstrate the potential of beam oscillation techniques for quality improvements in laser cutting.

Sign in / Sign up

Export Citation Format

Share Document