Effects of top-hat laser beam processing and scanning strategies in laser micro-structuring

Hoang Le, Pavel Penchev, Anne Henrottin, David Bruneel, Vahid Nasrollahi, Jose Ramos-de-Campos, Stefan Dimov

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)
229 Downloads (Pure)


The uniform energy distribution of top-hat laser beams is a very attractive property that can offer some advantages compared to Gaussian beams. Especially, the desired intensity distribution can be achieved at the laser spot through energy redistribution across the beam spatial profile and, thus, to minimize and even eliminate some inherent shortcomings in laser micro-processing. This paper reports an empirical study that investigates the effects of top-hat beam processing in micro-structuring and compares the results with those obtainable with a conventional Gaussian beam. In particular, a refractive field mapping beam shaper was used to obtain a top-hat profile and the effects of different scanning strategies, pulse energy settings, and accumulated fluence, i.e., hatch and pulse distances, were investigated. In general, the top-hat laser processing led to improvements in surface and structuring quality. Especially, the taper angle was reduced while the surface roughness and edge definition were also improved compared to structures produced with Gaussian beams. A further decrease of the taper angle was achieved by combining hatching with some outlining beam passes. The scanning strategies with only outlining beam passes led to very high ablation rates but in expense of structuring quality. Improvements in surface roughness were obtained with a wide range of pulse energies and pulse and hatch distances when top-hat laser processing was used.
Original languageEnglish
Pages (from-to)1-17
Number of pages17
Issue number2
Publication statusPublished - 20 Feb 2020

Bibliographical note

Funding Information:
Funding: The research was supported by two H2020 Factory of the Future projects, “Modular laser based additive manufacturing platform for large scale industrial applications” (MAESTRO, Grant agreement number 723826) and “High-Impact Injection Moulding Platform for mass-production of 3D and/or large micro-structured surfaces with Antimicrobial, Self-cleaning, Anti-scratch, Anti-squeak and Aesthetic functionalities” (HIMALAIA, Grant agreement number 766871). Also, the research was carried out with the framework of the regional ESIF project “Smart Factory Hub” (SmartFub).

Publisher Copyright:
© 2020 by the authors.


  • beam shapers
  • top-hat laser beam
  • gaussian laser beam
  • micro-structuring
  • pulse energy
  • hatch distance
  • pulse distance

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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