## 4 Conclusions  
From the simulation results of the separation process, it was observed that at lower rotational speeds, the separation rate between raisins and adhered foreign materials was suboptimal, with a low separation rate for adhered impurities. As the rotational speed increased to 400 r/min, the separation performance significantly improved, leading to a higher separation rate for adhered foreign materials. Further increasing the speed to 600 r/min achieved a satisfactory separation state, where most adhered impurities were effectively separated. However, when the rotational speed exceeded 600 r/min, although the separation rate for adhered impurities remained high, excessively high speeds increased the risk of raisin breakage. Regarding the screening process simulation, stem and branch fragments exhibited a favorable separation rate even at low airflow velocities due to their shape and density characteristics, but this resulted in a relatively high raisin loss rate. As the airflow velocity increased to 10 m/s, the removal rate of stems and branches improved, while the raisin loss rate decreased. For stones, their high density enabled effective screening at lower airflow velocities, but excessively high velocities compromised screening performance. The screening rate of plastic fragments depended on their density and shape: lighter plastic fragments could be separated at lower velocities, whereas heavier ones required higher velocities for effective separation. Ultimately, an airflow velocity of 11 m/s was identified as optimal. From the perspective of the actual removal effect of the equipment and relevant experiments, the optimal actual rotational speed and the wind speed of the raisin foreign matter removal system designed in this paper are 650 r/min and 11 m/s, respectively. The equipment has a material processing capacity of 120 kg/h, with a separation rate of 93.76%, a damage rate of 3.05%, a residue rate of 4.28%, a removal rate of 94.52%, and a carry-over ratio of 71:1. It possesses the capability for automated separation and screening of adhered foreign matters, providing new ideas and methods for the development of related technologies. It can effectively enhance the purity and quality of raisin products, improve production efficiency, and reduce labor costs. However, there are still some deficiencies in this study. Subsequent research can be carried out from the following aspects: equipment processing capacity, equipment's removal of non-rigid foreign matters, and the external structure of the equipment. First, regarding the equipment processing capacity, although the equipment's processing capacity is higher than that of manual labor (10-20 kg/h), it is still relatively low compared with existing equipment that directly removes raisins with adhered foreign matters. Subsequent improvements to the structure are required to increase the overall processing capacity of the equipment. Second, concerning the equipment's removal of non-rigid foreign matters, currently, the foreign matters targeted by the equipment are fruit stems, branches, stones, and plastics, while there is a lack of research on foreign matters such as nylon strips and ropes. Subsequent research can focus on foreign matters like nylon strips and ropes and combine the processing methods for rigid and non-rigid foreign matters to improve the applicability of the equipment. Finally, with regard to the external structure of the equipment, currently, the equipment only uses aluminum profiles to fix each module. In the future, the external frame can be replaced with a sheet metal enclosure and undergo corresponding surface treatment. Additionally, a visual window can be added to directly observe the operating status inside each module. R.Z. : conceptualization, methodology, writing--reviewing and editing. M.N. : data curation, writing--original draft preparation, visualization. H.M.: supervision, software. Z.Z. : validation. All authors have read and agreed to the published version of the manuscript.