## 4 Discussion  
In the presented design, each Chinese medicine powder gallipot is equipped with its own base with a powder discharge mechanism. 3D printing was used for the prototype of the gallipot base, demonstrating the feasibility of this design. For future commercialization, the gallipot base can be mass produced, and the cost per unit will be low due to its simple design. Since each gallipot has its own base, cross-contamination of the powder will not occur while discharging. Moreover, the power driving the discharge mechanism comes from the stepping motor on the weighing mechanism via the coupling of the coupler and the drive. Although many gallipot bases are required for each shelf, only one weighing mechanism is needed for each shelf. The stepping motors used on the weighing mechanism for rotating the coupler, flipping the medicine spoon, and retracting/extending the retractable platform are 200 steps per revolution at 100 Hz. The average speed of powder discharge is 0.22 g/s. Faster stepping motors could be used to improve the discharge speed for commercialization of this machine. The number of shelves can be increased in accordance with the needs of the application, as an aluminum extrusion frame is utilized. The presented machine has two shelves, with a total of 10 gallipots. If 100 gallipots were needed, a 5-shelf machine could be designed with 20 gallipots on each shelf. The size of such a design would have a height of 160 cm and a width of 200 cm. The estimated cost for this 5-shelf 100-gallipot machine would be $1800. Since powder discharge is achieved by the coupling of the coupler teeth and the drive teeth, it is necessary to precisely move the weighing mechanism to the gallipot base at the right position so that the rotation motor is able to drive the discharge mechanism. Furthermore, it is also necessary to raise/lower the mixing bowl on the lifting platform to the right position in order to collect the powder from the medicine spoons. Positioning errors for both were all within 2 mm, satisfying the precision requirement. The weighing element used in this study can read up to 1 kg, at the resolution 0.01 g. The weighing average absolute errors were in the range of 0.03 g-0.28 g. For a 3-day, 9-dose prescription (3 doses per day), the weighing errors per dose were in the range of 0.003 g-0.03 g, which is acceptable. Since the weighing mechanism consists of three motors, a load cell, and other parts, its weight is not light. Moreover, its moving speed affects the dispensing time. A more powerful stepping motor is used for driving this weighing mechanism. Two different speed control curves, trapezoidal curve and S-curve, were tested. The average transverse moving speed of the S-curve was faster than that of the trapezoidal curve. The S-curve speed control was also more stable during starting and stopping periods than the trapezoidal speed control. With the help of the weighing mechanism, the powder consumption of each gallipot can now be systematically recorded in the database. Therefore, the development of a gallipot inventory becomes possible. In the future, a management system could be developed to send an alarm when a gallipot is almost depleted for replacement. Another interesting feature that would also be feasible is optimal gallipot location planning for faster dispensing. Based on historical statistical data, it would be possible to place the most commonly used Chinese medicine at locations as close as possible to the initial position of the weighing mechanism, resulting in faster dispensing. Since the gallipot bases were printed by a 3D printer, the quality of the gallipot bases leaves room for improvement in the commercialization of this machine. Nano coating can also be applied to gallipot \begin{table}
\begin{tabular}{c c c c c} \hline  & \multicolumn{3}{c}{**Unit: g/s**} \\ \hline  & 3 g & 5 g & 10 g & 15 g \\ \hline speed & 0.27 & 0.22 & 0.22 & 0.19 \\ \hline  & \multicolumn{3}{c}{average speed} & & 0.22 \\ \hline \end{tabular}
\end{table} 
Table 7: Discharge speed.