Laser polishing of additive manufactured aluminium parts by modulated laser power

Markus Hofele*, André Roth, Jochen Schanz, Johannes Neuer, David K. Harrison, Anjali K.M. De Silva, Harald Riegel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)
2 Downloads (Pure)

Abstract

In this study a new approach to laser polishing with periodic modulated laser power in the kilohertz regime is introduced. By varying the modulation frequency and modulation time, different periodic laser power curves with varying minimum, peak and average laser power can be created. The feasibility of the method is shown by polishing of vertical built AlSi10Mg L-PBF parts with an initial roughness of Ra = 12.22 µm. One polishing pass revealed a decreasing surface roughness with increasing energy density on the surface up to Ra = 0.145 µm. An increasing energy density results in a rising remelting depth between 50 and 255 µm and a rising relative porosity of 0.3% to 4.6%. Furthermore, the thermal process stability, analysed by the melt pool length in scanning direction, reveals a steadily increasing melt pool dimension due to component heating. Multiple laser polishing passes offers a further reduced surface roughness, especially at higher modulation frequencies and provides an improved orientation independent roughness homogeneity. The process stability regarding varying initial surface roughness revealed an almost constant relative roughness reduction rate with an achievable roughness variation after two polishing passes between Ra = 0.13–0.26 µm from an initial state of Ra = 8.0−19.2 µm.

Original languageEnglish
Article number1332
Number of pages30
JournalMicromachines
Volume12
Issue number11
DOIs
Publication statusPublished - 30 Oct 2021

Keywords

  • additive manufacturing
  • laser remelting
  • 3D printing
  • selective laser melting (SLM)
  • surface quality
  • aluminium AlSi10Mg
  • laser powder bed fusion (L-PBF)
  • surface remelting

ASJC Scopus subject areas

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

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