Effects of anisotropic and isotropic LIPSS on polymer filling flow and wettability of micro injection molded parts

Gnilitskyi, Iaroslav; Alnusirat, Walid; Sorgato, Marco; Orazi, Leonardo; Lucchetta, Giovanni

doi:10.1016/j.optlastec.2022.108795

Cited by 5 publications

(5 citation statements)

References 32 publications

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“…Concerning wall slip, it is generally neglected in conventional injection molding, although it could play a significant role at the microscale [16]. Wall slip can be ascribed to the disentanglement of the bulk chains when attached to the mold walls and may increase filling length [15]. However, in the cases reported in this work, the wall slip phenomenon did not occur, as can be observed from the optical micrographs (Figures 5 and 6): no sharkskin [22] is visible in any of the obtained specimens.…”

Section: Resultsmentioning

confidence: 99%

“…The formation of weld lines and their location along the flow path is a well-studied phenomenon in conventional injection molding; however, only a few papers are devoted to micro-injection molding [11,[13][14][15][16]. As the weld line can significantly lower the mechanical strength of µIM parts, it is relevant to clarify the position of weld lines and also to provide possible routes for limiting weld line formation.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Weld Lines in Micro-Injection Molding

Liparoti,

De Piano,

Salomone

et al. 2023

Materials

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Micro-injection molding (µIM) is a widespread process for the production of plastic parts with at least one dimension, or feature, in the microscale (conventionally below 500 µm). Despite injection molding being recognized as a robust process for obtaining parts with high geometry accuracy, one last occurrence remains a challenge in micro-injection molding, especially when junctions are present on the parts: the so-called weld lines. As weld lines are crucial in determining mechanical part performances, it is mandatory to clarify weld line position and characteristics, especially at the industrial scale during mold design, to limit failure causes. Many works deal with weld lines and their dependence on processing parameters for conventional injection molding, but only a few works focus on the weld line in µIM. This work examines the influence of mold temperature on the weld line position and strength by both experimental and simulation approaches in µIM. At mold temperatures below 100 °C, only short shots were obtained in the chosen cavity. At increased mold temperatures, weld lines show up to a 40% decrease in the whole length, and the overall tensile modulus doubles. This finding can be attributed to the reduction of the orientation at the weld line location favored by high mold temperatures. Moldflow simulations consistently reproduce the main features of the process, weld line position and length. The discrepancy between experimental and simulated results was attributed to the fact that crystallization in flow conditions was not accounted for in the model.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of Weld Lines in Micro-Injection Molding

Liparoti,

De Piano,

Salomone

et al. 2023

Materials

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“…In addition, the laser-induced periodical surface structures (LIPSS), which are microand nanoscale rough structures formed by laser irradiation, can significantly change the surface morphology and chemical composition of the material, thus altering its surface energy and roughness [99][100][101][102][103]. For instance, Gaudiuso et al [104] used sub-THz bursts of femtosecond laser pulses to prepare surface-textured copper with superhydrophobic properties.…”

Section: Design Strategy Of Laser-fabricated Oil-water Separation Mat...mentioning

confidence: 99%

Laser Manufacturing of Superwetting Oil–Water Separation Materials: A Review

Xiong,

Zhu,

Jiang

et al. 2024

Separations

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The frequent occurrence of oil spills and the massive discharge of oily wastewater pose a significant threat to sustainable and healthy human development. Therefore, it is of importance to effectively separate oil–water mixtures. Inspired by nature, many superwetting surfaces/materials for oil–water separation have been developed in recent years. However, these surfaces/materials are subject to certain limitations and are unable to fully meet practical needs. With the advancement of laser technology, a novel solution has been provided for fabricating superwetting oil–water separation materials. Based on the design theory and separation mechanism, this paper summarizes the research progress of the laser-fabricated superwetting surfaces/materials for oil–water separation in recent years. First, the basic wetting theory, design strategy, and oil–water separation mechanism of the laser-fabricated materials are introduced in detail. Subsequently, the laser-fabricated oil–water separation materials, including superoleophilic/superhydrophobic materials, superhydrophilic/superoleophobic materials, and materials with reversible or superamphiphilic wettability, are systematically summarized and analyzed. Finally, the challenges and future research directions of laser-fabricated superwetting oil–water separation materials are discussed.

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“…[13] LIPSS can be fabricated on various types of solid surfaces, including metals, [14][15][16] semiconductors, [10,13,17,18] and polymers. [19][20][21][22] Ultrafast lasers enable the achievement of periodicities well below the laser wavelength, spanning from a few tens of nanometers to a few microns. [23,24] This capability encompasses metals, semiconductors, polymers, and even materials with a bandgap higher than the laser wavelength.…”

Section: Introductionmentioning

confidence: 99%

“…[ 13 ] LIPSS can be fabricated on various types of solid surfaces, including metals, [ 14–16 ] semiconductors, [ 10,13,17,18 ] and polymers. [ 19–22 ]…”

Section: Introductionmentioning

confidence: 99%

Beyond the Microscale: Advances in Surface Nanopatterning by Laser‐Driven Self‐Organization

Nakhoul,

Colombier

2024

Laser & Photonics Reviews

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Designing complex local properties that seamlessly integrate efficient functions into processed materials presents a formidable challenge. A promising solution has emerged in the form of ultrafast laser‐surface structuring. Through time‐controlled polarization ultrafast irradiation at the picosecond timescale, spontaneous self‐organization of surfaces can be induced. The thermal gradient length scale unfolds on the micro‐ and nanoscale, instigating thermoconvection that leads to structured surfaces upon quenching. Convective instabilities dynamically shape intricate yet self‐regulated periodic relief structures. The ability to achieve laser‐induced self‐organization in both surface dimensions holds immense scientific importance, as it unlocks the potential to create uniform periodic 2D patterns by harnessing the inherent regulation of nonlinear dynamics processes in fluids. This comprehensive review explores recent advances in understanding and leveraging ultrafast laser‐induced self‐organization for precise patterning across versatile scales and applications. The insights herein hold the potential to drive significant advancements in nanoscale manufacturing through 2D laser‐induced periodic surface structures.

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Effects of anisotropic and isotropic LIPSS on polymer filling flow and wettability of micro injection molded parts

Cited by 5 publications

References 32 publications

Analysis of Weld Lines in Micro-Injection Molding

Analysis of Weld Lines in Micro-Injection Molding

Laser Manufacturing of Superwetting Oil–Water Separation Materials: A Review

Beyond the Microscale: Advances in Surface Nanopatterning by Laser‐Driven Self‐Organization

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