## 3 Results  
### Results of Extrudability Tests of the Mycelium-Based Mixtures  
The sieve analysis of the 100 g of ground Ecovative mixture provided detailed particle size distribution data with powder weight retained for each sieve size and the normalized cumulative percentage, as shown in Figure 8. The D10, D50, and D90 values were calculated to be 412 \(\upmu\)m, 1227 \(\upmu\)m, and 1833 \(\upmu\)m, respectively. These values represent the powder particle sizes at which 10%, 50%, and 90% of the sample's mass is finer. In materials science, D10, D50, and D90 are crucial metrics used to describe the spread of particle sizes within a  
Figure 7: Visual configuration of the cylindrical samples as per the L9 orthogonal array. powder, impacting properties such as flowability, packing density, and surface area. For this study, these metrics help ensure the resulted paste from this powder has consistent rheological properties for EAM, avoiding nozzle blockages and maintaining print quality. The majority of the particles fall within the 850 \(\upmu\)m to 1400 \(\upmu\)m range, as highlighted by the steep increase in the cumulative curve (Figure 8). The detailed particle size distribution is shown in Table 5.  
The detailed particle size distribution and the corresponding D-values provide a comprehensive understanding of the paste's suitability for the intended robotic EAM process. The viscosity and particle size of the paste allowed for consistent extrusion with an 8 mm nozzle without any blockage. To develop the paste directly from ground Ecovative mixture, bypassing the initial colonization step, the water content was reduced by 54%, adding 600 mL of water per 100 g of ground Ecovative mixture to maintain the integrity of the printed beads. Although no ATP assays were conducted, the streamlined workflow resulted in visible mycelial growth within 7 days. As shown in Figure 9, the mycelium formed dense, uniform hyphal networks across the surface after 7 days, similar to the morphology observed in conventional workflows using growth-bag-based colonization [12; 13; 16]. The visual assessment of the samples prepared with varying ratios of psyllium husk (PH) to water (W), detailed in Table 2, showed that sample C (Figure 10), with a 4% PH to W ratio, exhibited the best stability and form. This sample was selected for robotic EAM purposes in this study. The specific paste mixture ratios by weight are 5:30:1.2:0.8, respectively, for GM:W:PH:F. The paste ratio translates to adding 600 mL of water (W), 24 g of psyllium husk (PH), and 16 g f flour (F) per 100 g of ground Ecovative mixture (GM). The printed layers adhered well in sample C. As per the new workflow that we  
Figure 8: Powder size distribution of 100 g of ground Ecovative mixture. \begin{table}
\begin{tabular}{c c c c} \hline
**Sieve Aperture Size** **(mm)** & **Weight Retained** **(g)** & **Cumulative** **Percentage (\%)** & **Normalized Cumulative** **Percentage (\%)** \\ \hline \(<\)212 & 1.8 & 1.8 & 1.826 \\
500 [212–500] & 9.8 & 11.6 & 11.765 \\
600 [500–600] & 1.0 & 12.6 & 12.779 \\
850 [600–850] & 2.0 & 14.6 & 14.807 \\
1400 [850–1400] & 49.6 & 64.2 & 65.112 \\
2000 [1400–2000] & 33.8 & 98.0 & 99.391 \\
2360 [2000–2360] & 0.2 & 98.2 & 99.594 \\
2360\(\leq\) & 0.4 & 98.6 & 100.000 \\ \hline \end{tabular}
\end{table} 
Table 5: Particle distribution of the ground Ecovative mixture. propose for EAM of mycelium-based mixtures using Ecovative's Dehydrated Grow-It-Yourself Mushroom(r) Material (Ecovative Design LLC, Green Island, NY, USA), skipping the mycelium inoculation and primary colonization steps proved to be efficient. The proposed EAM workflow successfully sustained fungal growth while shortening the total timeline of EAM by more than half when compared to the workflow in the literature [12; 13; 16]. In order to assess the generalizability of the proposed ANN architecture for predicting extrusion speeds in the robotic fabrication of mycelium-based composites, we conducted a 5-fold cross-validation.