Soft Computing Techniques for Laser-Induced Surface Wettability Control

Making decisions and deducing control actions in manufacturing environments requires considering many uncertainties. The ability of fuzzy logic to incorporate imperfect information into a decision model has made it suitable for the optimization of both productivity and final quality. In laser surface texturing for wettability control, in fact, these aspects are governed by a complex interaction of many process parameters, ranging from those connected with the laser source to those concerning the properties of the processed material. The proposed fuzzy-based decision approach overcomes this difficulty by taking into account both the random error, associated with the process variability, and the systematic error, due to the modelling assumptions, and propagating such sources of uncertainties at the input level to the output one. In this work, the laser surface texturing was carried out with a nanosecond-pulsed laser on the surfaces of AISI 304 samples, changing the laser scanning speed, the hatch distance, the number of repetitions, and the scanning pattern. A significant change of the contact angle in the range 24–121° is observed due to the produced textures. The fuzzy maps highlight the inherent uncertainty due to both the laser texturing process and the developed model.

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A Simple Model to Predict Machined Depth and Surface Profile for Picosecond Laser Surface Texturing

Applied Sciences ◽

10.3390/app8112111 ◽

2018 ◽

Vol 8 (11) ◽

pp. 2111 ◽

Cited By ~ 2

Author(s):

Jieyu Xian ◽

Xingsheng Wang ◽

Xiuqing Fu ◽

Zhengwei Zhang ◽

Lu Liu ◽

...

Keyword(s):

Mathematical Model ◽

Surface Texturing ◽

Surface Profile ◽

Picosecond Laser ◽

Scanning Speed ◽

Laser Surface ◽

Laser Surface Texturing ◽

Micro Channels ◽

Surface Profiles ◽

Simulation Parameters

A simple mathematical model was developed to predict the machined depth and surface profile in laser surface texturing of micro-channels using a picosecond laser. Fabrication of micro-craters with pulse trains of different numbers was initially performed. Two baseline values from the created micro-craters were used to calculate the estimated simulation parameters. Thereafter, the depths and profiles with various scanning speeds or adjacent intervals were simulated using the developed model and calculated parameters. Corresponding experiments were conducted to validate the developed mathematical model. An excellent agreement was obtained for the predicted and experimental depths and surface profiles. The machined depth decreased with the increase of scanning speed or adjacent interval.

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Laser surface texturing of tool steel: textured surfaces quality evaluation

Open Engineering ◽

10.1515/eng-2016-0012 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 5

Author(s):

Peter Šugár ◽

Jana Šugárová ◽

Martin Frnčík

Keyword(s):

Laser Beam ◽

Tool Steel ◽

Surface Texturing ◽

Scanning Speed ◽

Laser Surface ◽

Laser Surface Texturing ◽

Fibre Laser ◽

Textured Surfaces ◽

Machined Surface ◽

Ytterbium Fibre Laser

Abstract In this experimental investigation the laser surface texturing of tool steel of type 90MnCrV8 has been conducted. The 5-axis highly dynamic laser precision machining centre Lasertec 80 Shape equipped with the nano-second pulsed ytterbium fibre laser and CNC system Siemens 840 D was used. The planar and spherical surfaces first prepared by turning have been textured. The regular array of spherical and ellipsoidal dimples with a different dimensions and different surface density has been created. Laser surface texturing has been realized under different combinations of process parameters: pulse frequency, pulse energy and laser beam scanning speed. The morphological characterization of ablated surfaces has been performed using scanning electron microscopy (SEM) technique. The results show limited possibility of ns pulse fibre laser application to generate different surface structures for tribological modification of metallic materials. These structures were obtained by varying the processing conditions between surface ablation, to surface remelting. In all cases the areas of molten material and re-cast layers were observed on the bottom and walls of the dimples. Beside the influence of laser beam parameters on the machined surface quality during laser machining of regular hemispherical and elipsoidal dimple texture on parabolic and hemispherical surfaces has been studied.

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Improving fluid retention properties of 316L stainless steel using nanosecond pulsed laser surface texturing

Journal of Laser Applications ◽

10.2351/7.0000199 ◽

2020 ◽

Vol 32 (4) ◽

pp. 042018

Author(s):

Mahmood Al Bashir ◽

Rajeev Nair ◽

Martina M. Sanchez ◽

Anil Mahapatro

Keyword(s):

Stainless Steel ◽

316L Stainless Steel ◽

Surface Texturing ◽

Pulsed Laser ◽

Fluid Retention ◽

Laser Surface ◽

Laser Surface Texturing ◽

Nanosecond Pulsed Laser

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Performance and Accuracy of the Shifted Laser Surface Texturing Method

Micromachines ◽

10.3390/mi11050520 ◽

2020 ◽

Vol 11 (5) ◽

pp. 520

Author(s):

Jiří Martan ◽

Denys Moskal ◽

Ladislav Smeták ◽

Milan Honner

Keyword(s):

Depth Profile ◽

Processing Speed ◽

Temperature Increase ◽

Surface Texturing ◽

Scanning Speed ◽

Laser Surface ◽

Laser Surface Texturing ◽

Profile Measurement ◽

Heat Accumulation ◽

Usage Efficiency

A shifted laser surface texturing method (sLST) was developed for the improvement of the production speed of functional surface textures to enable their industrial applicability. This paper compares the shifted method to classic methods using a practical texturing example, with a focus on delivering the highest processing speed. The accuracy of the texture is assessed by size and circularity measurements with the use of LabIR paint and by a depth profile measurement using a contact surface profiler. The heat accumulation temperature increase and laser usage efficiency were also calculated. The classic methods (path filling and hatch) performed well (deviation ≤ 5%) up to a certain scanning speed (0.15 and 0.7 m/s). For the shifted method, no scanning speed limit was identified within the maximum of the system (8 m/s). The depth profile shapes showed similar deviations (6% to 10%) for all methods. The shifted method in its burst variant achieved the highest processing speed (11 times faster, 146 mm2/min). The shifted method in its path filling variant achieved the highest processing efficiency per needed laser power (64 mm2/(min·W)), lowest heat accumulation temperature increase (3 K) and highest laser usage efficiency (99%). The advantages of the combination of the shifted method with GHz burst machining and the multispot approach were described.

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Does laser surface texturing really have a negative impact on the fatigue lifetime of mechanical components?

Friction ◽

10.1007/s40544-021-0508-2 ◽

2021 ◽

Author(s):

Chia-Jui Hsu ◽

Andreas Stratmann ◽

Simon Medina ◽

Georg Jacobs ◽

Frank Mücklich ◽

...

Keyword(s):

Boundary Lubrication ◽

Surface Texturing ◽

Contact Stresses ◽

Laser Surface ◽

Laser Surface Texturing ◽

Wear Loss ◽

Textured Surface ◽

Periodic Patterns ◽

Rolling Bearings ◽

Fatigue Lifetime

AbstractLaser surface texturing (LST) has been proven to improve the tribological performance of machine elements. The micro-scale patterns manufactured by LST may act as lubricant reservoirs, thus supplying oil when encountering insufficient lubrication. However, not many studies have investigated the use of LST in the boundary lubrication regime, likely due to concerns of higher contact stresses that can occur with the increasing surface roughness. This study aims to examine the influence of LST on the fatigue lifetime of thrust rolling bearings under boundary lubrication. A series of periodic patterns were produced on the thrust rolling bearings, using two geometrically different designs, namely cross and dimple patterns. Base oil ISO VG 100 mixed with 0.05 wt% P of zinc dialkyldithiophosphate (ZDDP) was supplied. The bearings with cross patterns reduce the wear loss by two orders of magnitude. The patterns not only retain lubricant in the textured pockets but also enhance the formation of an anti-wear tribofilm. The tribofilm generation may be improved by the higher contact stresses that occur when using the textured surface. Therefore, in contrast to the negative concerns, the ball bearings with cross patterns were instead found to increase the fatigue life by a factor of three.

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Tribological effects of laser surface texturing and residual stress

Industrial Lubrication and Tribology ◽

10.1108/ilt-11-2016-0282 ◽

2018 ◽

Vol 70 (1) ◽

pp. 126-132 ◽

Cited By ~ 7

Author(s):

Shuwen Wang ◽

Feiyan Yan ◽

Ao Chen

Keyword(s):

Residual Stress ◽

Wear Resistance ◽

Friction And Wear ◽

Surface Texturing ◽

Laser Surface ◽

Friction Reduction ◽

Laser Surface Texturing ◽

Wear Testing ◽

Content Type ◽

Surface Textures

Purpose The purpose of this paper is to investigate the tribological effects of laser surface texturing (LST) and residual stress on functional surfaces. Design/methodology/approach Three different surface textures (circular dimple, elliptical dimple and groove) with two different textured area ratios (10 and 20 per cent) are designed and fabricated by a Picosecond Nd YAG Laser machine. The friction and wear performance of textured specimens is tested using a UMT-2 friction and wear testing machine in mixed lubrication. Findings Test results show that elliptical dimples exhibit the best performance in wear resistance, circular dimples in friction reduction and grooves in stabilization of friction. The surfaces with larger textured area density exhibit better performance in both friction reduction and wear resistance. The improved performance of LST is the coupled effect of surface texture and residual stress. Originality/value The findings of this study may provide guidance for optimal design of functional surface textures in reciprocating sliding contacts under mixed or hydrodynamic lubrication, which can be used in automotive and other industrial applications.

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Effect of Micro-Manufacturing Processes on Surface Behavior

ASME 2007 International Manufacturing Science and Engineering Conference ◽

10.1115/msec2007-31113 ◽

2007 ◽

Cited By ~ 1

Author(s):

Tiffany Davis ◽

Jian Cao ◽

Wei Chen ◽

Q. Jane Wang ◽

Cedric Xia ◽

...

Keyword(s):

Surface Texture ◽

Surface Texturing ◽

Steel Sample ◽

Laser Surface ◽

Laser Surface Texturing ◽

Copper Sheet ◽

Property Variation ◽

Nano Indentation ◽

Interface Surface ◽

Significant Difference

Surface texturing has become a valuable technique for reducing friction and wear in contacting parts; laser surface texturing is one such method used to create micro-dimples on the interface surface. This work investigates the surface material property variation caused by laser surface texturing. The hardness and modulus of elasticity of a steel laser surface texture sample were evaluated near the dimples and away from the dimpled zone through nano-indentation. Resulting data shows that no significant difference exists between the material properties from the two positions. An alternate technique for surface texture generation was also explored, involving the use of micro-punches to create surface features in a metal sample. Computational simulations were performed using a second material underneath a thin copper sheet. The second material was present to serve as a support and to allow extensive deformation of the top material. The choice of the support material and ratio of material thicknesses was optimized to minimize pile up. Trials were conducted for three base supporting materials: PTFE, PMMA, and aluminum. Results show that PMMA performed better than the other materials. Positive deflection was minimized when the PMMA thickness was at least fifteen times that of the copper sheet. Physical experiments were completed with a thin copper sheet to verify the results. An array of micro-indentations was also created in a bulk steel sample. In order to assess the effect of dimpling via micro-forming, nano-indentation was performed near and far from the deformed material of the dimples. Similar to the laser textured sample, no significant differences were found between the two locations.

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Effectiveness of multi-shape laser surface texturing in the reduction of friction under lubrication regime

Industrial Lubrication and Tribology ◽

10.1108/ilt-03-2015-0041 ◽

2016 ◽

Vol 68 (1) ◽

pp. 116-124 ◽

Cited By ~ 11

Author(s):

Dawit Zenebe Segu ◽

Pyung Hwang

Keyword(s):

Hydrodynamic Lubrication ◽

Surface Texturing ◽

Laser Surface ◽

Laser Surface Texturing ◽

Textured Surface ◽

Content Type ◽

Laser Ablation Process ◽

Specific Formula ◽

Steel Surfaces ◽

Lubrication Conditions

Purpose – The purpose of this paper is to investigate and discuss the effect of multi-shape laser surface texturing (LST) steel surfaces on tribological performance. Design/methodology/approach – The textured surface with some specific formula arrays was fabricated by laser ablation process by combining patterns of circles and triangles, circles and squares and circles and ellipses. The tribological test was performed by a flat-on-flat tribometer under dry and lubrication conditions, and results were compared with that of untextured surface. Findings – The results showed that the textured surface had better friction coefficient performance than the untextured surface due to hydrodynamic lubrication effect. Through an increase in sliding speed, the beneficial effect of LST performance was achieved under dry and lubrication conditions. Originality/value – This paper develops multi-shape LST steel surfaces for improving the friction and wear performance under dry and lubrication conditions.

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