Towards Large Area Submicron Surface Texturing by Femtosecond Laser Irradiation of Microparticle Arrays

Results of the work in the Laser4Fun project has been published as:

Jean-Michel Romano, Rajib Ahmed, Antonio Garcia-Giron, Pavel Penchev, Olivier Dellea, Stefan Dimov. Towards Large Area Submicron Surface Texturing by Femtosecond Laser Irradiation of Microparticle Arrays. 2nd World Congress on Micro and Nano Manufacturing (September 2018); doi: 10.3850/978-981-11-2728-1_10

Abstract

The direct laser submicron texturing of X6Cr17 stainless steel plates is reported. A hexagonal close-packed monolayer of 1um transparent silica microspheres deposited onto the metallic surface was irradiated with near-infrared femtosecond laser source to generate an array of Photonic Jets (PJ). The PJ intensity profiles were calculated by simulation. PJ full width at half maximum was estimated to be ~500nm on the surface. The influence of pulse energy and focal offset on material removal and microspheres’ ejection was studied. Different 1um-periodic submicron topographies were fabricated by a single-shot irradiation, i.e. ranging from 30nm-height bumps to 200nm-to-1um diameter holes. Consecutive multi pulse processing generated triangular laser-induced surfaces structures (LIPSS). In addition, the dry laser cleaning effect and large area texturing employing PJ were investigated.

Triangular self-organized surface textures produced by femtosecond laser irradiation on stainless steel and titanium alloy

Results of the work in the Laser4Fun project has been published as:

Jean-Michel Romano, Antonio Garcia-Giron, Pavel Penchev, Stefan Dimov. Triangular self-organized surface textures produced by femtosecond laser irradiation on stainless steel and titanium alloy. 2nd World Congress on Micro and Nano Manufacturing (September 2018); doi: 10.3850/978-981-11-2728-1_09

Abstract

The large area uniformity of laser-induced periodic surface structures (LIPSS) on ferritic stainless steel and titanium alloy is studied. A single-step process was designed to generate low spatial frequency LIPSS (LSFL) over relatively large areas. For the first time, a new LIPSS morphology is fabricated using near-infrared ultrashort pulsed laser. Extraordinarily uniform self-organized triangular structures in hexagonal arrangements were fabricated in the subwavelength range. The generation of such LSFL was found to be highly repeatable, not material dependent but very sensitive to the used laser processing settings. Therefore, the sensitivity of triangular-LSFL formation to pulse fluence and scanning speed were investigated.

Vittorio Vercillo runner up of Best Speaker Award

Last 11th of September 140 people, among students, supervisors and management, gathered in the ZAL (Zentrum für Angewandte Luftfahrtforschung) facilities in Hamburg for the 11th edition of the Airbus PhD Day 2018. Vittorio Vercillo, an Early Stage Researcher (ESR) in the Laser4Fun project, was awarded of the Best Speaker Award, Runner Up, for his contribution “Laser micro-/nano-structuring to produce icephobic surfaces”. In the picture, Vittorio receives the award from Dr. Michael Schoenwetter, Airbus R&T Partnerships & Contracting.

VERCILLO-Phd-Day-2018
Vittorio Vercillo (left) receives the award from Dr. Michael Schoenwetter

Contribution to The Laser User magazine

AILU magazine coverSome research performed within the Laser4Fun consortium was advertised in the The Laser User magazine (Issue 89 Summer 2018). The “Focus on Research” section highlighted the work of the University of Birmingham on DLW applied to anti-wetting and anti-icing properties, performed in collaboration with the Universidad Politécnica de Madrid and Airbus Group Innovation.

The Laser User magazine is edited quarterly by the Association of Lasers Users (AILU), the UK industrial/academic laser community.

To read the article: AILU Focus on Research

No more cleaning: Lasers make the lotus effect on aircraft

Filigree engravings on external surfaces of aircraft are intended to ensure that airflow remains smooth and drag on the aircraft low. For this, engineers at the Fraunhofer Institute for Material and Beam Technology IWS, the Technische Universität Dresden and Airbus have developed a laser process that produces textured surfaces at high throughput making surface contamination more difficult.
More details can be found at:

Biomimetic Surface Structuring Using Laser Based Interferometric Methods

Results of the work in the Laser4Fun project has been published as:

Andrés Fabián Lasagni, Sabri Alamri, Alfredo Ismael Aguilar-Morales, Florian Rößler, Bogdan Voisiat and Tim Kunze. Biomimetic Surface Structuring Using Laser Based Interferometric Methods. Appl. Sci. 2018, 8(8), 1260

Abstract

This review investigates the capabilities of laser-based interferometric methods for producing structures with multiple-scaled surface features imitating natural examples. Firstly, laser interference lithography is used to produce hierarchical patterns with length-scales in the micrometer and sub-micrometer range. Different strategies are discussed to produce a wide variety of periodic arrays, depending on the number of resist lasers used as well as the way in which the exposure steps are organized. After that, periodic patterns are fabricated on polymers using ns laser pulses from an UV-laser system. Additionally in this case, multiple-scale patterns are produced by using different strategies. A similar approach is described to treat metallic surfaces of steel X6Cr17 and a titanium alloy Ti6Al4V. The geometry of the produced microstructures was characterized using scanning electron microscopy and confocal microscopy. Measurement of water contact angle is performed for both polymer and metallic surfaces..

Link(s)

Laser4Fun session at LPM2018 conference in Edinburgh, Scotland, UK

The 19th International Symposium on Laser Precision Microfabrication (LPM 2018, www.lpm2018.org) takes place on June 25-28, 2018 in Edinburgh, Scotland, UK. This symposium is the world’s number one meeting of the laser user community where the most advanced developments and recent trends in laser application for fine and precise fabrication of diverse materials are discussed between industry, research and academia.

Today, Tuesday June 26th, a whole session was dedicated to presentations by near all our ESRs, disseminating results from the Laser4Fun project.

LPM2018-laser4fun
Photo: Giuseppe Giannuzzi

Luigi Capuano and Marek Mezera attended the Photonics Event in The Netherlands

On June 19th ESRs Luigi Capuano and Marek Mezera attended the Photonics Event 2018 in Enschede, The Netherlands, see https://photonics-event.nl/home-eng/. This event is the annual meeting point for the photonics community in the Benelux and Germany. At this event researchers, developers, designers and engineers working in the application and development of photonics meet to discuss the latest trends and developments. For companies from end markets such as Agriculture, Food, Healthcare, Lifescience or the High-tech Systems sector, it is a good opportunity to get acquainted with the technology and the companies that can support development.

Luigi Capuano (left) and Marek Mezera at the Photonics Event 2018.
Luigi Capuano (left) and Marek Mezera at the Photonics Event 2018.

Influence of processing parameters on surface texture homogeneity using Direct Laser Interference Patterning

Results of the work in the Laser4Fun project has been published as:

Alfredo I. Aguilar-Morales, Sabri Alamri, Tim Kunze, Andrés Fabián Lasagni. Influence of processing parameters on surface texture homogeneity using Direct Laser Interference Patterning. Optics & Laser Technology. Volume 107, November 2018, Pages 216–227.

Abstract

Surface functionalities in the field of tribology, wettability, biocompatibility and holographic marking introduced by well-defined surface structures strongly depend on the surface texture homogeneity and quality. This work presents strategies for the fabrication of homogeneous periodic surface microstructures employing the Direct Laser Interference Patterning (DLIP) technology with the fundamental transverse mode (TEM00) emitted from a nanosecond laser source. Ti6Al4V substrates are structured using line-like patterns with spatial periods of 7.20 µm, 5.82 µm and 4.31 µm. The impact of various DLIP process parameters such as laser fluence, pulse overlap, hatch distance and spatial period on the produced surface microstructures is introduced and the consequences on the surface texture homogeneity are discussed. Large-area analysis of micro structures is carried out through white light interferometry and scanning electron microscopy. A quantitative measurement scheme of the pattern homogeneity, based on topographical properties such as kurtosis, standard deviation and mean structure height was introduced. Furthermore, the influence of a second modulation arising from the employed hatch distance has been identified. A quantitative parameter, the surface error percentage, has been introduced and employed for the characterization of pattern homogeneity. It was found that specially for larger spatial periods and surfaces treated at high laser fluence, pulse-to-pulse overlaps and a short hatch distance, the overall surface texture homogeneity could be improved up to ∼80–90%.

Link(s)