Abstract
In this paper, we investigate the influence of the following parameters: pulse duration, pulse repetition rate, line-to-line and pulse-to-pulse overlaps, and scanning strategy on the ablation of AISI 316L steel and CuZn37 brass with a nanosecond, 1064-nm, Yb fiber laser. The results show that the material removal rate (MRR) increases monotonically with pulse duration up to the characteristic repetition rate (f0) where pulse energy and average power are maximal. The maximum MRR is reached at a repetition rate that is equal or slightly higher as f0. The exact value depends on the correlation between the fluence of the laser pulses and the pulse repetition rate, as well as on the material properties of the sample. The results show that shielding of the laser beam by plasma and ejected material plays an important role in reducing the MRR. The surface roughness is mainly influenced by the line-to-line and the pulse-to-pulse overlaps, where larger overlap leads to lower roughness. Process optimization indicates that while operating with laser processing parameters resulting in the highest MRR, the best ratio between the MRR and surface roughness appears at ~50% overlap of the laser pulses, regardless of the material being processed.
Highlights
Laser ablation, a process in which material is removed layer by layer by systematic guidance of a laser beam over a sample, known as laser engraving or laser milling, has been established in recent decades as an alternative to conventional methods of material removal in a wide range of industrial applications [1,2,3,4]
In addition to many outstanding properties of laser milling compared to conventional milling techniques, the recently increased interest of the industry [5,6,7,8,9] has been mainly influenced by the development of new laser sources which are more efficient and adaptable in terms of pulse energies and temporal shapes
We have investigated the influence of processing parameters on the ablation of AISI
Summary
A process in which material is removed layer by layer by systematic guidance of a laser beam over a sample, known as laser engraving or laser milling, has been established in recent decades as an alternative to conventional methods of material removal in a wide range of industrial applications [1,2,3,4]. In addition to many outstanding properties of laser milling compared to conventional milling techniques, the recently increased interest of the industry [5,6,7,8,9] has been mainly influenced by the development of new laser sources which are more efficient and adaptable in terms of pulse energies and temporal shapes. High quality laser engraving depends on minimization of unwanted side effects, such as the heat-affected zone (HAZ), burrs, microcracks, and remolten material. It is well-known that these side effects increase by increased pulse durations [10,11,12,13,14,15].
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