Laser Microtexturing Research Articles

Mechanism analysis of dual wavelength laser welding AlN-PC joint based on microtexture treatment

High-strength interfacial bonding between ceramics and transparent polymers is hardly to be achieved, especially in the field of optical packaging of biochips. This paper proposes a novel laser welding method that enhances the joint strength between aluminum nitride (AlN) ceramic and polycarbonate (PC) by laser surface microtexturing. The study investigates the influence of welding methods and microtextures on welding effectiveness, elucidating the bonding mechanisms of the joints. The obtained results showed that dual wavelength laser welding effectively achieves the connection between AlN ceramic and PC. Laser microtexturing increases surface roughness and contact area, leading to stronger mechanical interlocking and overall joint strength. The highest shear strength reached up to 14.66 MPa with longitudinal grooves microtexture. The laser microtexturing improves the hydrophilicity of the AlN surface, facilitating more effective bonding between the materials. The bonding mechanisms at the joint interface include both mechanical interlocking and chemical bonding. Microtexturing improves the stress distribution at the joint interface. The formation of C-O-Al chemical bonds at the interface effectively enhances the joint strength. Longitudinal grooves microtexture exhibit a higher substrate fracture rate due to stress concentration and capillary pores. In contrast, staggered square holes microtexture provide superior mechanical performance through uniform stress distribution and robust mechanical interlocking.

Investigation of Laser micro-textured triboelectric nanogenerator based self-powered vibration sensor for industry 4.0 application

Self-powered sensors detect a variety of crucial parameters for industrial processes without any external power source for Industry 4.0. It has capabilities to acquire, analyze, and make decisions on real-time data, these sensors are essential for the advancement of automated production systems and smart factories. In this regard, Triboelectric nanogenerators (TENGs) have potential to provide effective solution as self-powered vibration sensor for continuous monitoring of machine tools. Different techniques have been used to enhance the performance of TENG such as material doping, chemical etching, ion injection, etc. However, laser surface texturing is a low-cost, contact less, efficient technique which can be used for improving the response of TENG-based self-powered vibration sensors. In this context, Laser Induced Backside Texturing is a laser micro texturing approach to improve the electrical performance. It induces waviness and surface roughness, which leads to increased surface charge density and triboelectrification capabilities. In this work, laser micro texturing was performed using with 405 nm wavelength semiconductor diode laser to generate line pattern texture on the Fluorinated Ethylene Propylene (FEP). Laser textures TENG (LT-TENG) was developed with laser textured FEP as tribonegative material and pristine Aluminium as tribopositive material, the open-circuit voltage, short-circuit current and power density achieved 23 %, 41 %, and 47 % enhancement respectively, generating 794 V, 44 µA, and 2371.6 µW/cm2. This increase in output leads to an increased sensitivity of the sensor. When mounted on the machines, LT-TENG was able to detect their working state, vibration frequency, and harmonics i.e. 46, 92, 184 Hz for the vacuum pump and 140, 280, 410 Hz for the heat gun. These detected vibration frequencies, and their harmonics were similar to the frequencies detected by the commercial accelerometer (CTC AC115), confirming potential use of LT-TENG as a low-frequency vibration sensor. The developed LT-TENGs was integrated with the Internet of Things (IoT) supported microcontroller, which collects real-time data for continuous monitoring and analysis for machine health monitoring in smart devices.

Morphological evolution and biocorrosion response of a hierarchical micro- nano-structured Ti alloy: Physico-chemical characterization and electrochemical studies

In the present study, hierarchically architectured micro/nano-scale surface topography inspired from the leaves of Euphorbia myrsinites was fabricated on Ti-6Al-4V ELI alloy through laser micro-texturing (LT) followed by alkaline hydrothermal treatment (HT). The hybrid (LT + HT) surface revealed distinct multi-scaled morphological features differing from individually treated LT and HT surfaces. Alongside topographical cues, the evolved elemental and phase constitution also influenced the wettability, mechanical and corrosion properties. The (LT + HT) surface exhibited improved hydrophilicity and reduced surface stiffness of ~14.82 GPa (closely mimicking human bone-tissue), attributing to a hydrothermally-induced porous titania-layer extending up to a few microns depth. Corrosion tests in Hank's solution revealed that HT alone couldn't substantially improve the corrosion resistance as compared to polished surface (control). Integrating LT with HT not only altered the surface topography, but also introduced a relatively denser barrier-oxide layer (laser-induced oxidation) that transformed into a stable anatase-rich phase structure upon hydrothermal etching and subsequent annealing. Both LT and (LT + HT) recorded reduced corrosion current densities and suppressed corrosion rates, but (LT + HT) performed substantially better in the anodic polarization regime (till 2 V), with passivation current densities reduced by at least two orders of magnitude. AC impedance studies affirmed the role of an adsorptive nanostructured outer-layer in (LT + HT) towards accelerating the passivation kinetics, while the inner barrier layer imposed higher charge transfer resistance. Also, better biomineralization ability was observed in (LT + HT) after 30 days immersion in Hank's solution, with Ca: P (at. ratio) ~1.4, thereby indicating higher propensity of apatite nucleation.

Capillary-Driven Water Transport by Contrast Wettability-Based Durable Surfaces.

Controlling water transport and management is crucial for continuous and reliable system operation in harsh weather conditions. Passive strategies based on nonwetting surfaces are desirable, but so far, the implementation of superhydrophobic coatings into real-world applications has been limited by durability issues and, in some cases, lack of compliance with environmental regulations. Inspired by surface patterning observed on living organisms, in this study we have developed durable surfaces based on contrast wettability for capillary-driven water transport and management. The surface fabrication process combines a hydrophobic coating with hard-anodized aluminum patterning, using a scalable femtosecond laser microtexturing technique. The concept targets heavy-duty engineering applications; particularly in aggressive weather conditions where corrosion is prevalent and typically the anodic aluminum oxide-based coating is used to protect the surface from corrosion, the concept has been validated on anodic aluminum oxide coated aluminum alloy substrates. Such substrates with contrast wettable characteristics show long-term durability in both natural and lab-based artificial UV and corrosion tests where superhydrophobic coatings tend to degrade.

Crestal Bone and Soft Tissue Stability Surrounding Laser Microtextured Collar of Dental Implant; A 3- Year Clinical and Radiographic Evaluation

Crestal Bone and Soft Tissue Stability Surrounding Laser Microtextured Collar of Dental Implant; A 3- Year Clinical and Radiographic Evaluation

Improvement of thermal plasma sprayed coating adhesion strength by laser microtexturing of aluminum

Grit blasting and laser processing are two common methods used for surface microtexturing to enhance coating adhesion strength. This paper reports a thermomechanical method of laser microtexturing of Al 7075 alloy using a nanosecond pulsed laser to generate a large increase in surface area. The entire surface area of the substrate was microtextured using laser melting, ablation, and resolidification. The laser microtextured surface morphology consisted of tightly packed pillar-like surface features. The morphology of the microtexture was varied by controlling the laser processing parameters. The laser microtextured surface was coated with metallic particles using a thermal spray process. The tensile adhesive strength of the thermally sprayed metallic coating was higher by over 17% for a 5-μm deep microtexture, compared to that of grit-blasted samples. Also, this is the highest reported adhesion strength for laser-based microtexturing methods for thermally sprayed bond coatings.

Effect of Laser Micro-Texturing on Laser Joining of Carbon Fiber Reinforced Thermosetting Composites to TC4 Alloy.

Carbon fiber reinforced thermosetting composites (CFRTS) and TC4 alloy are important structural materials for lightweight manufacturing. The hybrid structure of these two materials has been widely used in the aerospace field. However, the CFRTS-TC4 alloy joint formed by the traditional connection method has many challenges, such as poor environmental adaptability and stress concentration. Laser micro-texturing of metal surface-assisted laser connection of CFRTS and TC4 alloy has great potential in improving joint strength. In order to study the effect of laser micro-texturing on the laser bonding of CFRTS and TC4 alloy, the simulation and experimental research of laser welding of TC4 alloy and CFRTS based on laser micro-textures with different scanning spacings were carried out, and the interface hybrid pretreatment method of laser cleaning and laser plastic-covered treatment was introduced to assist the high-quality laser bonding of heterogeneous joints. The results showed that the established finite element model of CFRTS-TC4 alloy laser welding can predict the temperature field distribution of the joint during the welding process and reflect the forming mechanism of the joint. The laser micro-textures with different scanning spacings will lead to a difference in the temperature field distribution on the polyamide (PA6) interface, which leads to a change in heat input on the CFRTS surface. When the laser scanning spacing is 0.3 mm, the joint strength can reach 14.3 MPa. The failure mechanism of the joint mainly includes the cohesive failure of the internal tear of the carbon fiber and the interfacial failure of the interface between the PA6 resin and the TC4 alloy.

The behavior of plasma sprayed thermal barrier coating with laser microtextured bond coat under high temperature testing

In this work, the laser microtexturing is exploratory studied for controlling the interface between the oxidation resistant metallic bond coat and thermally insulating ceramic top coat in Thermal Barrier Coatings.The 80 to 100 μm thick NiCrAlY layer was deposited by Atmospheric Plasma Spraying over the nickel-based super alloy substrate. Then, the infrared fiber nanosecond laser was used for shaping the topography of bond coat prior to the top coat deposition. The surface geometry was adapted by selecting the laser set-up operational conditions, mainly: (i) laser power, (ii) frequency, (iii) scanning velocity and (iv) inter-pass spacing. The two groove-based patterns were finally selected for further work together with one as-sprayed bond coat, as a reference. The 8 wt% yttria stabilized zirconia (8YSZ) was deposited by means of Suspension Plasma Spraying over all three types of bond coats. The samples were then subjected to isothermal oxidation and thermal cyclic fatigue testing in order to study the influence of bond coat topography on the overall behavior of coatings under high temperature conditions. The microstructural studies revealed that the as-sprayed bond coat topography may be progressively modified by multistep laser microtexturing. The uniform bond coat topography is found to be beneficial in promoting formation of homogeneous, columnar-like top coat. However, the modification of bond coat topography affects the behavior of the bond coat/top coat interface during high temperature testing. The study shows that the microtexture depth should be precisely controlled, otherwise the through bond coat thickness oxidation is observed, which has a detrimental effect on the overall durability of the TBC system. The bond coat asperity width plays also an important role. If it is too narrow, then the failure may propagate locally through the bond coat or the thermally grown oxide layer.

Soft and hard tissues analysis around tissue level implants with laser microtextured neck: a 12-month pilot study

OBJECTIVES: A flapless tissue level minimally invasive technique has been proposed for rehabilitation procedures with implants characterized by a laser modified neck surface. A promising computer- controlled laser microtextured technique which creates an implant neck surface with cell-sized microchannels (8 μm) has been developed. This preliminary clinical study aimed to evaluate soft and hard tissues … Continued

Nanosecond Laser Micro-Textured TC4 Double Sparse Surface and its Ice Suppression Characteristics

Nanosecond Laser Micro-Textured TC4 Double Sparse Surface and its Ice Suppression Characteristics

Soft and Hard tissues analysis around tissue level implants with laser microtextured neck: a 12-month pilot study

Objectives: A flapless tissue level minimally invasive technique has been proposed for rehabilitation procedures with implants characterized by a laser modified neck surface. A promising computer-controlled laser microtextured technique which creates an implant neck surface with cell-sized microchannels has been developed. This preliminary clinical study aimed to evaluate soft and hard tissues modification around implants … Continued

Impact of collar laser microtexturing on peri-implant health and disease: a retrospective clinical study.

This retrospective study was aimed to compare the clinical and radiographic outcomes of implants with the same body design but different collar surface (laser-microtextured vs. not laser-microtextured) after functional loading. Forty-three patients (29 females, 14 males) with 139 implants (60 laser-microtextured and 79 without laser microtexturing) were included in this study. Patients were consecutively included, and the data were collected during their implant maintenance visit. Clinical and radiographic parameters including probing depth (PD), bleeding on probing (BoP), and marginal bone loss (MBL) were recorded. In addition, the implant success index (ISI) score was determined. Statistical analysis was performed using the Mann-Whitney U test, the Kruskal-Wallis rank test, or the Pearson χ2 test, along with binary logistic regression (p < 0.05 was considered to be statistically significant). The median post-loading follow-up was 24months with 100% survival rate. There was no significant differences in terms of mean PD (3.01mm vs. 2.63mm), mean MBL (0.54 vs. 0.49mm), BoP (56.7% vs. 53.2%), and ISI score between laser-microtextured collars and implants without laser microtexturing. Logistic regression revealed arch as a significant predictor of peri-implantitis (p = 0.02). Within the limitations of this study, there was no statistically significant difference between the clinical and radiographic outcomes of implants with laser-microtextured and non-laser-microtextured collar designs. Clinical relevance Prospective studies with larger sample sizes and careful monitoring of implant placement protocols are needed for definite conclusions.

Erratum to: Fabrication of a Functional Relief on the Surface of a Polyvinyl Chloride Film by Nanosecond Laser Microtexturing

Erratum to: Fabrication of a Functional Relief on the Surface of a Polyvinyl Chloride Film by Nanosecond Laser Microtexturing

A Randomized Pilot Clinical and Microbiological Study Comparing Laser Microtextured Implants with and without Platform Switching

Minimising marginal bone loss around dental implants is of paramount importance. The success of methods such as platform switching (PS) and laser-micro-texturing (LM) are well documented. Whether or not a combination of these designs will further improve outcomes has not been studied previously. Hence, this prospective, randomized controlled single-centre pilot study compared the clinical and microbiological outcomes of implants with both PS and LM (test) to implants with only LM (control). A test and control implant were placed in thirteen patients totalling 26 implants. The primary investigated outcome was marginal bone level (MBL); secondary outcomes were peri-implant probing depths (PPD), bleeding on probing (BOP) and marginal tissue height (MTH). Additionally, the presence of five putative periodontal pathogens were assessed using real-time polymerized chain reaction. At 12 months the overall implant survival rate was 95.8%. MBL change was not found to be different between test and control at any time points, but a significant change was detected within the test implants at 6 months compared to baseline (p = 0.006). No differences were found in the secondary outcomes. Average PPD at 12 months was 2.68 ± 0.73 mm and 2.30 ± 0.46 mm and average change in MTH was 0.05 ± 0.72 mm and −0.24 ± 0.59 mm at tests and controls. No differences were reported in BOP frequency. Total periodontal pathogens count revealed no significant difference among control, test implants and adjacent tooth sites. Within the limitations of this study, it can be concluded that the addition of PS to LM implants does not significantly alter either short-term clinical outcomes or the vulnerability to pathogenic microflora colonization.

Tribological and microstructural characterization of laser microtextured CoCr alloy tested against UHMWPE for biomedical applications

The longevity of metal-on-polyethylene (MoP) joint replacements, in which a polished CoCr component articulates with a polyethylene liner, may be restricted by mechanical instability or inflammation resulting from osteolysis caused by polyethylene wear debris. Recently, laser surface texturing (LST) has emerged as an effective method to improve the tribological performance of lubricated friction pairs. The present work reports a microstructural and tribological study of surface microtextured CoCr alloy discs, modified by the LST method using a pulsed Nd:YAG laser, tested against Ultra High Molecular Weight Polyethylene (UHMWPE) cylindrical pins. Four different texturing patterns varying laser parameters such as peak power, pulse width, repetition rate and travel speed were investigated. An untextured set of CoCr alloy discs was used as reference. The microstructure and mechanical properties of the microtextured CoCr alloy discs were investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, atomic force microscopy, profilometry and nanoindentation test. The coefficient of friction and wear of the UHMWPE pins were determined by means of a pin-on-disc tribometer under lubricated sliding conditions. The microstructural analysis on the laser microtextured CoCr alloy revealed a grain refinement of secondary phases with absence of typical carbides resulting in an increased nanohardness. In addition, all texturing patterns on the CoCr alloy discs promoted a reduction on the coefficient of friction, compared against untextured CoCr alloy discs. Furthermore, it was found that UHMWPE wear was reduced when articulating against dimple textured CoCr alloy discs.

Effect of Interface Pretreatment of Al Alloy on Bonding Strength of the Laser Joined Al/CFRTP Butt Joint.

In the present research, the carbon fiber reinforced thermoplastic (CFRTP) was laser joined with the Al alloy whose joining interface was pretreated by laser micro-texturing, anodizing, and hybrid of laser micro-texturing and anodizing. The surface morphology of the pretreated Al joining interface and bonding strength of the corresponding Al/CFRTP butt joint were investigated. The results show that the laser micro-texturing has fabricated the micro-pit or micro-furrow in the Al joining interface. With the increasing of laser scanning times, the size of the micro-pit or micro-furrow decreases, when the laser scanning distance is constant. The bonding strength of the Al/CFRTP butt joint with Al joining interface pretreated by micro-texturing fluctuates with the increasing of laser scanning distance and times, reaching the maximum value of 20 MPa at laser scanning distance of 0.1 mm and 1 time. The anodizing pretreatment has formed the Al2O3 oxide layer on the Al joining interface. The Al/CFRTP butt joint with Al joining interface pretreated by anodizing obtains the maximum bonding strength of 11 MPa at anodizing time of 10 min. The hybrid pretreatment of micro-texturing and subsequent anodizing fabricates the regular grid structure with smooth micro-furrow and micro-pit, while the hybrid pretreatment of anodizing and subsequent micro-texturing fabricates the Al joining interface with explosive micro-pit and micro-furrow. The bonding strength of the Al/CFRTP butt joint with hybrid-pretreated Al joining interface is relative better than that of the Al/CFRTP butt joint with anodizing-pretreated Al joining interface but almost lower than that of the Al/CFRTP butt joint with micro-texturing pretreated Al joining interface. Such results should be attributed to the surface morphology of the Al joining interface.

Titanium implants modified by laser microtexturing enhance the bioactivity of gastric epithelial cells and fibroblast cells.

The clinical application of anastomotic instruments improves the efficiency of the digestive tract surgery. However, the stapler with titanium nails implanted is still controversial in terms of anastomotic complications, and further improvement and optimization are needed. The purpose of this study was to explore the optimal microtextured parameters that could enhance the bioactivity of titanium implants in vitro. Laser microtexturing technology was used to construct the groove-type microstructural surfaces with different parameters, and human gastric mucosal epithelial cells (GES-1 cells) and mouse fibroblasts (3T3 cells) were cultured on the surface of the titanium plates in vitro. The data of cell adhesion, cell proliferation and cell activity were obtained and statistically analyzed. The textured titanium plates meet the expected design. GES-1 and 3T3 cell adhesion were better in the surface of titanium plates in microstructural group than that in the polished group. GES-1 and 3T3 cells also showed higher proliferative activity in the microstructural group compared with the polished group. The laser textured titanium plates have good groove-type microstructure, which increase the surface roughness, change the surface wettability, promote the adhesion, proliferating and orderly growth of GES-1 and 3T3 cells, and show good biological properties.

Comparative study between implants with and without laser micro textured collar

Purpose: The aim of this study is to compare between implants with and without laser microtextured collar.Methods: 20 patients divided into two groups 10 patients in each group. Group 1 received implants with laser microtextured collar (laser lok); group 2 received implants without laser micro textured collar (oxy implant). The parameters for the cases are modified plaque index (MPI), modified sulcar bleeding index (MSBI), pocket depth (PD) and marginal bone level (MBL). All patients received implants with delayed loading protocole .Results: the mean and standard deviation were calculated for each group .changes between two groups in modified plaque index and modified sulcar bleeding index show no statistical difference. There was a statistical difference between the group one and group two in pocket depth and marginal bone level.Conclusion: The laser lok micro textured collar implant system appeared more effective design as compared to oxy implant system without laser micro textured collar.

Laser Microtextured Surfaces for Friction Reduction: Does the Pattern Matter?

Frictional performances of different textures, including axisymmetric and directional patterns, have been tested in the mixed and the hydrodynamic lubrication regimes. Experimental results, corroborated by numerical simulations, show that the leading parameter is the geometrical pattern void ratio since a large number of dimples offers, at low speed, a trap for debris whereas, at high speed, due to the flow expansion in each micro-hole, fosters a fluid pressure drop, the consequent insurgence of micro-cavitation and, ultimately, the reductions of the shear stresses. Furthermore, in this paper, it is shown that, by means of directional textures, equivalent hydrodynamic wedges can be built up, thus establishing different friction performances depending on the flow direction.

Surface Textured Drill Tools—An Effective Approach for Minimizing Chip Evacuation Force and Burr Formation During High Aspect Ratio Machining of Titanium Alloy

Abstract The real challenge pertaining to high aspect ratio drilling is the rapid increase in chip evacuation force due to the chip clogging phenomenon occurring at higher drilling depths. The clogged chips will further impede the reachability of cutting fluid at the machining zone leading to the tool temperature buildup. This will eventually result in the catastrophic failure of the tool. Hence, in the present work, an attempt has been made to minimize the chip evacuation force by functionalizing the drill tool surfaces based on the laser microtexturing principle. Microscale textures in the form of circular dimples were created on the flute and margin side of the drill tool with an objective to control the sliding friction, thereby minimizing the chip clogging effect. The effectiveness of the functionalized drill tools were assessed mainly based on the variation in thrust force and torque. Drilling experiments showed a net reduction of 17.18% in thrust force and 26.98% in torque while machining Ti–6Al–4V using the flute and margin textured tool, which justified the effectiveness of micro scale textures in minimizing the chip evacuation forces. The experimental analysis was further extended in terms of burr height evaluation, where FMT tools were found to be highly effective in burr height reduction (1.29 mm), showing a net reduction of 54.26% when compared with the non-textured tool. The outcomes from this research work will be highly beneficial for the manufacturing industries including aerospace, automobile, and spacecraft as high aspect ratio drilling of titanium alloys are still categorized to be the most challenging machining process owing to its lower thermal conductive property.