Figure 3.

Repeatability of the manufacturing. Four different manufacturing samples (1–4). (a) 3D projection of the channel at the cross region, (b) Channel profile, (c) 3D projection of the main channel, (d) surface width of the channel and (e) colored photo to show width and depth. Sample 1 surface width $208 \mathsf{\mu }\mathrm{m}$, Sample 2: surface width $212 \mathsf{\mu }\mathrm{m}$, Sample 3: surface width $211 \mathsf{\mu }\mathrm{m}$ and Sample 4: surface width $216 \mathsf{\mu }\mathrm{m}$.