## 3 Result
### Testing and Evaluation of Sorting/Ejection Equipment for Foreign Object Removal
#### 3.3.1 Testing of Separation and Sieving Processes  
This paper employs rolling extrusion separation and pneumatic sieving to achieve efficient separation of raisins from adhered foreign objects and subsequent sieving of the separated raisin-foreign object mixture. These two critical stages correspond to the separation process and the sieving process, respectively. In the separation process, motor speed serves as the most pivotal parameter, directly influencing the effectiveness of rolling extrusion separation. In the sieving process, the air velocity corresponding to fan speed becomes the core factor determining sieving accuracy. Given that the optimal ranges of motor speed and air velocity obtained through simulation require adaptive adjustment to actual operating conditions, conducting practical testing is essential. Testing enables precise evaluation of the applicability of simulation-derived parameters in real-world environments, allowing for fine-tuning of motor speed and air velocity to ensure optimal performance of both separation and sieving processes, thereby enhancing the stability of the raisin foreign object removal system. Figure 27: Equipment for separating and removing adhered foreign objects from raisins. Figure 26: Trajectory and velocity variation of raisins and various foreign objects during the screening process. For motor speed testing, five different test speeds were set based on the simulation-optimized value of 600 r/min: 500 r/min, 550 r/min, 600 r/min, 650 r/min, and 700 r/min. Adhered foreign object-contaminated raisins were then introduced into the rolling extrusion separation module for foreign object removal. After completion, key metrics were accurately recorded from the collection bin: counts of raisins without adhered foreign objects, raisins still with adhered foreign objects, damaged raisins, and raisins with adhered foreign object fragments. These data were used to calculate separation rate, breakage rate, and residue rate, with detailed results presented in Figure 28.  
In the fan wind speed testing section, based on the simulation-derived optimal wind speed of 11 m/s, three test wind speeds (10.5 m/s, 11 m/s, and 11.5 m/s) were configured. Subsequently, raisins adhered with foreign objects were introduced into the sieving module for separation. Following the sieving process, quantitative analysis was performed on key parameters including the count of foreign objects entering the raisin collection zone and the number of raisin particles migrating to the foreign object collection zone. Based on these quantified metrics, the removal rate and carry-over ratio were calculated, with experimental results detailed in Figure 29.  
A comparative analysis of key performance indicators during the separation process under varying rotational speeds revealed the following findings: As the motor speed increased from 500 r/min to 650 r/min, the separation rate exhibited an upward trend from 89.58% to 94.67%, while both the breakage rate and residue rate remained relatively stable. At this rotational speed, the balance among separation rate, breakage rate, and residue rate reached an optimal state, showing minimal deviation from the simulation-derived optimal speed range. This validates the rationality of the simulated rotational speed parameters, and through experimental optimization, the optimal operational conditions were achieved. When the speed was further increased to 700 r/min, no significant changes were observed in separation rate, residue rate, or breakage rate. Regarding the screening process under different air velocities, experimental data demonstrated that at 11 m/s wind speed, the screening rate reached its maximum value, accompanied by a carry-over ratio of 75:1. This outcome precisely matched the simulation-derived optimal wind speed, confirming the accuracy of the simulated air velocity parameters. This condition enabled effective separation of foreign objects from raisins while  
Figure 28: Separation metrics under different motor rotational speeds.