. Response to Surface Treatment: Surface Roughness Reduction
It can be seen (Figure 3a) that the low level values of both the surface treatment duration and the
chemical solution concentration showed a limited removal of the powder particles (experimental run
No. 1 and 6). An increase of the HF concentration resulted in a more effective removal of the attached
particles (run No. 3 and 8), especially when combined with a longer treatment duration (run No. 4 and 9).
The surface roughness analysis (Figure 3b) showed, only for structures produced with a designed
beam thickness of 180 μm, a progressive reduction in surface roughness with an increase of the treatment
duration and HF concentration. In the case of structures with a designed beam thickness of 140 μm, the
influence of the treatment parameters was less consistent. The largest change was observed for
experimental run No. 2. Additionally, a higher reduction in surface roughness was found for structures
with a designed beam thickness of 180 μm than for 140 μm when using the highest HF concentration and
treatment duration (run No. 4 and 9). The interaction plots, presented in Figure 3d, confirmed the higher
reduction of the surface roughness with increasing treatment duration and HF concentration.