Active reduction of waviness through processing with modulated laser power

Oreshkin, Oleg; Küpper, Moritz; Temmler, André; Willenborg, Edgar

doi:10.2351/1.4906622

Cited by 18 publications

(8 citation statements)

References 1 publication

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“…According to Bordatchev [ 25 ], potential applications of the technology are the structuring of moulds for the production of light guides and texturing metal surfaces. An approach for removing waviness was considered by Oreshkin Reference [ 26 ]; the principle is called destructive interference.…”

Section: State Of the Artmentioning

confidence: 99%

Shape Deviation of Surface Structures Produced by WaveShape (Structuring by Laser Remelting) on Ti6Al4V and a Method for Deviation Reduction

et al. 2021

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Laser structuring by remelting (WaveShape) is a manufacturing process for metal surfaces in which structures are generated without material removal. The structuring principle is based on the controlled motion of the three-phase line in the area of the solidification front. The contour of the solidification front is imprinted into the remelting track during the continuous solidification process. Typically, harmonic surface structures in the form of sinusoidal oscillations are generated by means of WaveShape with virtually no material loss. However, a significant shape deviation is often observed over a wide range of process parameters. In this study, it was found that much of the shape deviation is concentrated at a spatial wavelength equal to half the spatial wavelength used for structuring. Therefore, an approach to reduce the shape deviations was specifically investigated by superimposing a compensation signal on the harmonic structuring signal. In this approach, a compensation signal with half the spatial wavelength was varied in phase and amplitude and superimposed on the structuring signal. Amplitude and phase shift of the compensation signal were further investigated for selected laser beam diameters and spatial wavelengths. This demonstrated that a shape deviation of harmonic surface structures on titanium alloy Ti6Al4V could be reduced by up to 91% by means of an adapted compensation signal.

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Section: State Of the Artmentioning

confidence: 99%

Shape Deviation of Surface Structures Produced by WaveShape (Structuring by Laser Remelting) on Ti6Al4V and a Method for Deviation Reduction

et al. 2021

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“…Due to the extremely tiny beam diameter (<100 µm [214]) and tens of microseconds pulse duration [200], the existence time of laser formed micron molten pool (molten depth less than 6 µm [223]) is very short, and the fused material has solidified before the forming of next molten pool. For the spatial wavelength of initial surface roughness δ < 80 µm, CWLP has little effect [188], while PLP can further reduce the roughness to nano-scale [205]. Xiao et al [220] successfully eliminated the rainbow pattern on monocrystalline silicon by nanosecond pulsed laser, as shown in figure 28, which was produced by ultraprecision cutting, and reduced the roughness to 0.6 nm.…”

Section: Types Of Lmpmentioning

confidence: 99%

“…Phefferkorn et al [223,229,232] systematically explored effect of pulse width on surface topography, and found that long pulse width can form larger molten pool, which can reduce low-frequency roughness better. Because of the longer duration of larger molten pool, if the laser frequency is further increased until the pulse interval is less than molten pool duration, the continuous melting process will become a quasicontinuous melting process [205]. Laser diameter decreases with the increase of defocus amount [203,235,236].…”

Section: Machining Characteristics Of Lmpmentioning

confidence: 99%

Field-assisted machining of difficult-to-machine materials

Zhang,

Zheng,

Huang

et al. 2024

Int. J. Extrem. Manuf.

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Difficult-to-machine materials (DMMs) are extensively applied in critical fields such as aviation, national defense, biomedicine, and other key fields due to their excellent material properties. However, traditional machining technology is difficult to precisely machine DMMs due to poor surface quality and low processing efficiency. In recent years, as a new generation of machining technology, field-assisted machining (FAM) technology based on innovative principles such as laser heating, tool vibration, magnetic magnetization, and plasma modification provides a new solution for improving the machinability of DMMs. It is advantageous to prevent the shortcomings of traditional machining methods, and has become a hot topic of research in the domain of ultra-precision machining of DMMs. Many new methods and principles have been presented and investigated one after another, yet few researches have been analysed and summarized from a comprehensive standpoint. To fill this gap and understand the development trend of FAM, this study provides an important overview of FAM, covering different assisted machining methods, application effects, mechanism analysis, and equipment design. The current deficiencies and future challenges of FAM are summarized to lay the foundation for the further development of multi-field hybrid assisted and intelligent field-assisted machining technologies.

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“…Kuisat et al [8] found even for the direct laser interference patterning (DLIP on Ti64 and Scalmalloy©) process using ns laser pulses that this smoothing effect is inherent to the remelting process and occurs simultaneously to the DLIP process. This is similar to the WaveShape process, which achieves structuring and polishing in one process step [23] or even utilizes a spatially adapted laser power modulation for the reduction of waviness on a surface (Oreshkin et al [24]). Overall, the laser polishing process can be seen as a spatial low-pass filtering of a surface [25,26], resulting in an effective reduction of surface roughness.…”

Section: Introductionmentioning

confidence: 99%

Laser Micro Polishing of Tool Steel 1.2379 (AISI D2): Influence of Intensity Distribution, Laser Beam Size, and Fluence on Surface Roughness and Area Rate

Temmler

Cortina

Roß

et al. 2021

Metals

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Within the scope of this study, basic research was carried out on laser micro polishing of the tool steel 1.2379 (AISI D2) using a square, top-hat shaped intensity distribution. The influence of three different quadratic laser beam sizes (100 µm, 200 µm, 400 µm side length) and fluences up to 12 J/cm2 on the resulting surface topography and roughness were investigated. Surface topography was analyzed by microscopy, white light interferometry, spectral roughness analysis, and 1D fast Fourier transformation. Scanning electron microscopy and electrical discharge analyses indicate that chromium carbides are the source of undesired surface features such as craters and dimples, which were generated inherently to the remelting process. Particularly for high laser fluences, a noticeable stripe structure was observed, which is typically a characteristic of a continuous remelting process. Although the micro-roughness was significantly reduced, often, the macro-roughness was increased. The results show that smaller laser polishing fluences are required for larger laser beam dimensions. Additionally, the same or even a lower surface roughness and less undesired surface features were created for larger laser beam dimensions. This shows a potential path for industrial applications of laser micro polishing, where area rates of up to several m2/min might be achievable with commercially available laser beam sources.

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Active reduction of waviness through processing with modulated laser power

Cited by 18 publications

References 1 publication

Shape Deviation of Surface Structures Produced by WaveShape (Structuring by Laser Remelting) on Ti6Al4V and a Method for Deviation Reduction

Shape Deviation of Surface Structures Produced by WaveShape (Structuring by Laser Remelting) on Ti6Al4V and a Method for Deviation Reduction

Field-assisted machining of difficult-to-machine materials

Laser Micro Polishing of Tool Steel 1.2379 (AISI D2): Influence of Intensity Distribution, Laser Beam Size, and Fluence on Surface Roughness and Area Rate

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