## 3 Results  
At the end of the additive manufacturing process, the new rotor was subjected to measurements, weighed, and compared with the defective one (Figure 15). These operations revealed that the physical dimensions of the new rotor exhibit minimal dimensional deviation, approximately 0.01 mm (most likely a measurement error), and its weight is lower due to the reduced volume of the magnets used. The reduced mass of the rotor and the arrangement of the magnets one millimeter closer to the instantaneous center of rotation of the rotor reduce the moment of inertia, resulting in a faster response of the flowmeter to flowrate variations. Figure 16 illustrates the assembly process where the rotor has been mounted within the subassembly, and the flowmeter has been fully assembled. Figure 15: The measurement, weighing, and comparison of the new flowmeter rotor. Following the assembly of the flowmeter, functional tests were conducted in the General Hydraulics Laboratory of IHP using the servo-technical test stand facilities. These tests involved connecting the remanufactured flowmeter in series with another flowmeter (Figure 17)--a flowmeter with higher precision--and comparing the values transmitted by them using the \"LabVIEW\" (2019) data acquisition and processing software. The experimental setup included a variable flow control pump and control system, the remanufactured flowmeter, the reference flowmeter, a data acquisition board NI 6259, a 24 V power supply, a computing system, and a control panel with digital displays. Through this setup, a hydraulic fluid with variable flowrates ranging from 3.2 to 17.8 L/min (Figure 17) was circulated. On the panel with digital displays, it can be observed that, at a flowrate of 12.6 L/min, the pressure drop across the two flowmeters is 5.2 bar. The experimentation lasted 28.7 s, and Figure 18 presents the time variation of the flowrates for the two flowmeters (a) and details of this variation for three distinct periods: the beginning of the measurements (b), the end of the measurements (d), and the middle of the measurements (c). The red curve (Q1) represents the flowrate of the reference flowmeter, while the blue one (Q2) represents the flowrate of the remanufactured flowmeter. In the same figure, one can notice that, when changing the flowrate value, there is a small lag (delay) between the two flowrates, which is caused by the moment of inertia of the remanufactured flowmeter's rotor. Additionally, on the linear portions of the curve, the flowrate value of the remanufactured flowmeter is slightly higher, by approximately 0.05 L/min, compared to the reference flowmeter's value. This offset should be electronically applied in the data acquisition software afterward to ensure both flowmeters display identical values (calibration purposes). Figure 16: Mounting of the rotor in the flowmeter assembly. Figure 17: The experimental setup and data acquisition. Figure 19 displays the linear correlation between the two flowrates. If the correlation coefficient is close to zero, it indicates a lack of significant linear correlation between the two variables. Conversely, a correlation coefficient close to \(-1\) or \(+1\) signifies a strong linear correlation between the variables. The closer the correlation coefficient is to \(-1\) or \(+1\), the stronger the correlation is. Figure 18: The time variation of the flowrates for the two flowmeters and details of the variation. (**a**) Whole variation of flowrates for the two flowmeters; (**b**) Variation detail—beginning segment; (**c**) Variation detail—middle segment; (**d**) Variation detail—end segment. Comparing the measurement error of the remanufactured flowmeter with the reference flowmeter (Figure 20), there is a deviation of \(+0.28\) and \(-0.08\) L/min (absolute \(0.36\) L/min), with the absolute percentage error being less than \(1\%\) (\(+0.7\%\) and \(-0.2\%\)). These deviations primarily arise due to the lag between the two measurements. Figure 19: The linear correlation between the two flowrates.