# Design and Application of a New Visible Light-Curing 3D Printing Platform
## 3 Results
### Calculation of Burning Rate of Energetic Charge  
The mass burning velocity of energetic powder column was measured using the target line method. The linear burning rate can be calculated by the Formula (1). \[v=\frac{h}{t} \tag{1}\]  
where \(v\) denotes the 3D-printed powder column linear burning rate, mm\(\cdot\)s\({}^{-1}\); \(h\) refers to the distance between two target lines, mm; and \(t\) stands for burn time. The burning time of the energetic power column was recorded using an oscilloscope. The CH1 channel and CH2 channel of the oscilloscope are connected at both ends of the energetic power column, respectively, and the energetic power column is detonated by a detonator. The CH1 channel voltage of the oscilloscope changes when the powder column burns to target line 1, and the CH2 channel voltage changes when it burns to target line 2. The burning time of the powder column is obtained by observing the distance between the CH1 signal and the CH2 signal of the oscilloscope. The burning time of the energetic powder column is recorded using the oscilloscope, as shown in Figure 13. The burning rate and standard deviation of the energetic power column are shown in Table 8.  
Figure 12: Microstructure of energetic power column (**a**) Traditional pressure power column structure defects; (**b**) 3D printing of power column structure. Figure 13: Burning rate test oscilloscope waveform diagram. \begin{table}
\begin{tabular}{c c c c c c c} \hline  & **Length** & **Burning Time** & **Burning Rate** & **Average Burning Rate** & **Standard Deviation** & **Residue Ratio** \\  & **(mm)** & **(s)** & **(mm\(\cdot\)s\({}^{-1}\))** & **(mm\(\cdot\)s\({}^{-1}\))** & **(mm\(\cdot\)s\({}^{-1}\))** & **(\%)** \\ \hline
1\# & 6 & 5.13 & 1.169 & & & 2.912 \\
2\# & 6 & 5.32 & 1.128 & 1.165 & 0.0283 & 3.012 \\
3\# & 6 & 5.01 & 1.197 & & & 2.988 \\ \hline \end{tabular}
\end{table} 
Table 8: Combustion performance of energetic powder column. As shown in Table 8, according to formula 1, the length of the energetic power column is 6 mm, the average burning rate is 1.165 mm\(\cdot\)s\({}^{-1}\), and the standard deviation is 0.0283 mm\(\cdot\)s\({}^{-1}\). The difference in burning rate between power columns is not large, and the residue rate is small. The largest residue ratio, belonging to energetic power column 3#, is only 2.988%. The visible light-curing charge machine was used to charge the energetic slurry with a solid content of 80%. The cylindrical power column with a size of \(\Phi\)6 mm \(\times\) 6 mm was formed and ignited, and the combustion status of the energetic power column was observed and analyzed. The combustion effect of the energetic power column photographed with the camera shoot at a distance of 10 cm is shown in Figure 14.  
Figure 14 illustrates the combustion progression of the energetic propellant column and its state at various intervals. Between 1 s and 2 s, the power column ignites, producing a luminous yellow flame that projects uniformly in a specific direction. From 2 s to 4.5 s, the flame elongates, maintaining a stable combustion with a clear interface, and there is no emission of black smoke. As it transitions from 4.5 s to 5 s, the flame starts to diminish until the burn concludes. Throughout this process, the powder column exhibits consistent burning. The flame's elongation, followed by its reduction, suggests the complete reaction of the energetic powder column components and the high dispersion of the solid filler within the energetic slurry. The entire combustion is marked by a radiant flame, devoid of black smoke, and showcases parallel layer burning, producing a consistent yellow flame. The luminosity resulting from the energetic power column's combustion can be perceived as a point light source. This is directed towards the visible light detector's probe and is kept at a fixed distance. As the combustion ensues, its optical effect is captured by the detector probe and relayed to OPT2000.