## 2 Materials and Methods
### 3D Printer and Manufacturing Parameters  
The mSLA Anycubic M3 Premium 3D printer was used in the study (Figure 5). The 3D printer has a monochrome LCD matrix of 10.1 inches and a 7680 \(\times\) 4320 pixels resolution. The available working area on this 3D printer is 218.88 mm \(\times\) 213.12 mm, and the pixel size is 28.5 \(\upmu\)m. Considering this, the smallest voxel with an assumed layer thickness of 0.05 mm can be 0.0285 mm \(\times\) 0.0285 mm \(\times\) 0.05 mm. Hence, obtaining the smallest detail with a characteristic size of about 0.03 mm is theoretically possible. The matrix in the Anycubic M3 Premium 3D printer is indirectly illuminated by a lamp that emits UV radiation with a wavelength of 405 nm. A concave mirror reflects the UV radiation. As a result of this reflection, an even and perpendicular illumination of the LCD matrix is obtained. According to the specification, UV light power is 7.8 mW/cm\({}^{2}\). As for other parameters, the backlight uniformity expressed in absolute terms is 36.205 mW/cm\({}^{3}\) (90%), the collimation level is 3\({}^{\circ}\), and the stray light level is 1.26%. In the 3D printer, a 10.1\({}^{\prime\prime}\) (218 mm \(\times\) 122.3 mm) Anycubic Screen Protector film with a thickness of 0.1 mm and a claimed transmittance of about 96.9% is applied to the die. In addition, an FEB film with a thickness of 0.15 mm (actual, measured value) is used as the bottom of the vat. The study utilized Anycubic ABS-Like Resin Pro 2 resin (Shenzhen Anycubic Technology Co., Ltd., Shenzhen, China), and the manufacturer provided the recommended manufacturing parameters for the 3D printer model used (Table 1). However, we know from experience that the value of the parameters given by the manufacturer is imprecisely fixed, which means that some 3D prints often fail. Therefore, we treat these as the starting parameters for calibration. We developed our 3D printer \begin{table}
\begin{tabular}{c c c} \hline \hline
**Name of a Parameter** & **Manufacturer’s Recommended Values** & **Values Adopted in the Research Process** \\ \hline Layer thickness & 0.05 mm & 0.05 mm \\ Bottom exposure time & 25 s & 25 s \\ Bottom layers & 2 & 3 \\ Exposure time & 2.5 s & 2.25 s \\ Light-off & 0.5 s & 1.0 s \\ Bottom layer & 2 & 3 \\ Anti-aliasing & 1 & - \\ Z-lift distance & 8 mm & 8 mm \\ Z lift speed & 6 mm/s (360 mm/min) & 6 mm/s (360 mm/min) \\ Z retract speed & 6 mm/s & 6 mm/s \\ Resin temperature & 18–30 \({}^{\circ}\)C & 28 \({}^{\circ}\)C \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Manufacturing parameters adopted for the Anycubic ABS-Like Resin Pro 2 resin. Figure 5: The Anycubic M3 Premium 3D printer used in the research process. settings. Only minor modifications have been made to the manufacturer's data. Layer exposure time is assumed to be 2.25 s. Light-off was increased to 1 s, thereby minimizing trapped-bubble defects and improving layer thickness uniformity. The number of bottom layers was increased to 3, and 6 intermediate layers were used. No anti-aliasing was used. Advanced platform lift speed control was used. The lift speed for the first 2 mm from the bottom of the vat was 70 mm/min, then 360 mm/min for a distance of 8 mm (+6 mm). Access to the platform is 2 mm from the bottom of the vat at 360 mm/min. The last section of the approach was performed at a speed of 140 mm/min. During the tests, the temperature in the 3D printer chamber was kept constant at 28 degrees. As the temperature of the resin increases, its viscosity decreases. This facilitates the flow of resin from the workpiece into the vat and reduces the force exerted by the squeezed resin when the platform reaches the screen, especially for the former, where there are very short distances between the platform, which is a uniform flat aluminum surface, and the bottom of the vat. The chamber was heated up to the set temperature 15 min before the start of printing to allow time for the temperature of the printer components and resin to stabilize.