Surface treatment of additively manufactured metal parts for any arbitrary wetting state between superhydrophilic and superhydrophobic

Holder, Daniel; Hetzel, Florian; Weber, Rudolf; Graf, Thomas

doi:10.1016/j.procir.2022.08.014

Cited by 9 publications

(9 citation statements)

References 12 publications

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“…The wall of the left side shows a poor surface quality, a rough surface topography due to the adhering powder particles. These powder particles cause high roughness values, usually S a > 10 µm depending on the build angle [3]. Smoothing the walls with the AddSub method significantly reduces the roughness to S a ≈ 1 µm and thus allows to parts with a high surface quality to be produced.…”

Section: Smoothing the Walls Of Lpbfgenerated Metal Partsmentioning

confidence: 99%

“…For example, depth-controlled micromachining with ultrafast lasers enables a reduction of shape deviations and surface roughness of around sixty to eighty percent to just a few micrometers [1,2]. In addition, postprocessing with ultrashort laser pulses opens up the potential for further functionalization of surfaces by creating surface structures in the micrometer and nanometer range [3]. These surface structures can be used, for example, to improve water repellency and heat transfer in heat exchangers [4].…”

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confidence: 99%

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Bridging additive and subtractive manufacturing

Holder,

Henn,

Buser

et al. 2024

PhotonicsViews

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Additive manufacturing with laser powder‐bed fusion (PBF‐LB/M) can generate complex metal parts with a high degree of design freedom, which are already being used in various industries. However, the PBF‐LB/M process faces some limitations in achievable surface quality and feature size. To address these challenges, we have developed a novel hybrid manufacturing approach that combines additive manufacturing via PBF‐LB/M with subtractive manufacturing via ultrafast laser machining. By alternating between additive and subtractive processes, it is possible to not only mitigate the limitations of each process but also to introduce new functionality. This synergistic combination enables the creation of parts with superior surface finishes and deep and narrow internal features that are not possible with a single method alone.

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Section: Smoothing the Walls Of Lpbfgenerated Metal Partsmentioning

confidence: 99%

mentioning

confidence: 99%

Bridging additive and subtractive manufacturing

Holder,

Henn,

Buser

et al. 2024

PhotonicsViews

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“…Cooling systems and heat exchangers are usually made from metals due to their high heat conductivity. However, the contact angle of water droplets on metallic surfaces is typically in the range of 45° < θ < 83° and thus metal surfaces are hydrophilic 34 – 36 . The contact angle of a substrate mainly depends on the surface topography and the surface chemistry 34 , 37 – 39 and it can be modified by various surface functionalization processes 40 – 42 , such as laser structuring.…”

Section: Introductionmentioning

confidence: 99%

“…Laser texturing (also known as laser structuring) by direct laser interference patterning allows for the creation of microscopic and periodic features such as dimples or small holes on the surface with dimensions of a few micrometers 47 – 51 . Laser texturing by conventional scanning of the beam over the surface can be used for the creation of microscopic and periodic features such as spikes, holes, grooves and ripples on the surface with dimensions of a few micrometers down to few hundred nanometers, which are also known as laser-induced periodic surface structures (LIPSS) 34 , 36 , 52 – 58 . The latter approach with conventional scanning is especially interesting to shape the surface topography of large parts due to the low complexity of scanner-based setups and the potential for very high texturing rates 55 , 59 .…”

Section: Introductionmentioning

confidence: 99%

“…The type and the dimensions of the generated features during laser surface texturing by scanning mainly depend on the process parameters, such as the peak fluence 34 , 52 – 54 , 58 the pulse repetition rate 54 , the scanning speed 36 , 60 , the line spacing 55 and the number of pulses per spot 52 , 54 , 61 or the accumulated fluence 56 as well as the initial surface condition prior to texturing 36 , 57 .…”

Section: Introductionmentioning

confidence: 99%

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Enhancing heat transfer at low temperatures by laser functionalization of the inner surface of metal pipes

Holder,

Peter,

Kirsch

et al. 2024

Sci Rep

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The latent heat transfer during vapour condensation in the condenser section of passive heat transport devices such as the two-phase closed thermosiphon is limited by film condensation. Dropwise condensation provides an increase of the heat transfer coefficient by up to one order of magnitude and can be achieved with a water-repellant surface. The inner surface of pipes made from stainless steel was functionalized by laser surface texturing with ultrashort laser pulses and subsequent storage in a liquid containing long-chained hydrocarbons. The pipes were separated into half-pipes by wire eroding to enable laser texturing of the inner surface, and were then joined by electron beam welding after laser texturing. As a result, superhydrophobic and water-repellent surfaces with a contact angle of 153° were obtained on the inner surface of the pipes with a length of up to 1 m. The functionalized pipes were used in the condenser section of a two-phase closed thermosiphon to demonstrate a heat transfer rate of 0.92 kW at 45 °C, which is approximately three times the heat transfer rate of 0.31 kW of a smooth reference pipe.

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Titanium: A systematic review of the relationship between crystallographic profile and cell adhesion

Celles,

dos Reis

2024

J Biomed Mater Res

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Dental implant surface properties such as roughness, wettability, and porosity ensure cell interaction and tissue integration. The clinical performance of dental implants depends on the crystallographic texture and protein and cell bonds to the substrates, where grain size, orientation, and inclination are parameters responsible for favoring osteoblast adhesion and limiting bacterial adhesion. The lack of consensus on the best crystallographic plan for cell adhesion prompted this systematic review, which aims to answer the following question: “What is the influence of the crystallographic plane on titanium surfaces on cell adhesion?” by evaluating the literature on the crystallographic characteristics of titanium and how these dictate topographical parameters and influence the cell adhesion of devices made from this material. It followed the Preferred Reporting Standards for Systematic Reviews and Meta‐Analyses (PRISMA 2020) registered with the Open Science Framework (OSF) (osf.io/xq6kv). The search strategy was based on the PICOS method. It chose in vitro articles that analyzed crystallographic structure correlated with cell adhesion and investigated the microstructure and its effects on cell culture, different crystal orientation distributions, and the influence of crystallinity. The search strategies were applied to the different electronic databases: PubMed, Scopus, Science Direct, Embase, and Google Scholar, and the articles found were attached to the Rayyan digital platform and assessed blindly. The Joanna Bringgs Institute (JBI) tool assessed the risk of bias. A total of 248 articles were found. After removing duplicates, 192 were analyzed by title and abstract. Of these, 18 were selected for detailed reading in their entirety, 9 of which met the eligibility criteria. The included studies presented a low risk of bias. The role of the crystallographic orientation of the exposed faces in a multicrystalline material is little discussed in the scientific literature and its impact is recognized as dictating the topographical characteristics of the material that facilitate cell adhesion.

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Surface treatment of additively manufactured metal parts for any arbitrary wetting state between superhydrophilic and superhydrophobic

Cited by 9 publications

References 12 publications

Bridging additive and subtractive manufacturing

Bridging additive and subtractive manufacturing

Enhancing heat transfer at low temperatures by laser functionalization of the inner surface of metal pipes

Titanium: A systematic review of the relationship between crystallographic profile and cell adhesion

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