*2.2. Scaffold Geometry*

Figure 2 shows the scaffold geometry, which was used for the FE study and validation tests. A modified polar f2cc,z unit cell was used. A total number of four cells in radial direction (*n*1,2 = 4), a total number of 17 cells in circumferential direction (*m* = 17) and a total number of 12 cells in height direction (*n*<sup>3</sup> = 12) was chosen. The scaffold has a total height of *h* = 12 mm and a diameter of *d* = 10 mm. The nominal strut radius is *rs* = 0.1 mm. The cell width *b* results from *b* = (*d* − 2*Rm*)/(2*n*1,2) = 0.9 mm, where *Rm* = 1.4 mm is the radius of central cavity, or rather the inner radius of the first cell ring, measured at the cells edges. Since the cells only approximate a circle, the radial position of the midpoint of the cells side faces lies at *rm*,*<sup>i</sup>* = *ri* cos(*ϕ*/2) for the inner face and *rm*,*<sup>a</sup>* = *ra* cos(*ϕ*/2) for the outer face, where *ri* is the inner radius of the cell edges and *ra* is the outer radius of the cell edges and *ϕ* = 2*π*/*m* is the proportion that a cell has in the total circumference. The strut inclination *ω* of the circumferential diagonal struts can be calculated for the inner diagonals of each cell ring (*ωi*) and for the outer diagonals of each cell ring (*ωo*) as followed:

$$
\omega\_{i} = \arctan(h/b\_{i}); \omega\_{o} = \arctan(h/b\_{o}) \tag{2}
$$

The radial orientated diagonals strut inclination is equal for all cell rings and results from *ω<sup>r</sup>* = tan(*h*/*b*). Table 1 sums the resulting geometric parameters of the scaffold. It should be noticed that for the outer rings, the strut inclinations of the diagonals become lower 45°, which usually leads to unfavorable conditions in the AM process. By an optimization of the manufacturing parameters, see Section 2.1 for reference, and the good processability of the material, it was nevertheless possible to produce flat angles, as shown in Figure 3. The strut diameters of the manufactured scaffolds were measured at random positions, resulting in *rs* ≈ 0.092–0.106 mm, which lies in an acceptable tolerance range of the nominal strut radius.

**Table 1.** Resulting geometric parameters of the scaffold used for this study (*Rm* = 1.4 mm); *i* defines the actual ring, starting from the middle with *i* = 1 according to Figure 2.


**Figure 2.** Scaffold geometry used for the study.

**Figure 3.** Resulting LPBF produced scaffold used for the physical evaluation.
