# Design and Optimization of a Toothed-Plate Single-Roller Crushing Device for Waste Plastic Film
## 6 Conclusions  
A toothed-plate single-roller crushing device for waste plastic film was designed, and its working process and a crushing component design analysis have been described. Through theoretical analysis, it was found that the key factors affecting the crushing effect of the equipment include the feeding speed, the number of toothed plates, and the crushing roller rotation speed. Using the Box-Behnken design experimental method and considering the feeding speed, the number of toothed plates, and the crushing roller rotation speed as factors, a three-factor, three-level quadratic polynomial model was established with the size qualification rate and the impurity content of crushed film as the optimization indexes. The analysis results indicate that the size qualification rate and impurity content of the crushed film are 87.94% and 8.83%. After considering practical conditions, the actual verification parameters were determined; the feeding speed was set at 0.30 m/s, the number of toothed plates was 12, and the crushing roller rotation speed was selected as 815 r/min. Finally, verification tests were conducted, resulting in an actual size qualification rate of 82.551% and an impurity content of 9.57%. The errors compared to the predicted values were 6.13% and 8.38%, respectively. Both error values were within 9%, indicating that the optimized model is reliable and predictive. The design of the toothed-plate single-roller crushing device reduces cleaning difficulty and recycling processing costs and improves the quality of recycled products. Additionally, it will greatly increase the efficiency of the resource utilization of waste plastic film. However, there are still weaknesses in the crushing device in this study; for example, the toothed plates are not capable of crushing larger stones. Therefore, in future research, the material and shape of the toothed plates should be optimized to achieve the purpose of crushing stones without damage to the toothed plates.  
Conceptualization, K.G.; methodology, K.G. and H.Y.; software, K.G.; validation H.S. and H.Y.; formal analysis, X.C.; investigation, M.C.; resources, F.G.; data curation, K.G.; writing--original draft preparation, K.G.; writing--review and editing, Z.H.; visualization, Z.H.; supervision, M.C.; project administration, Z.H.; funding acquisition, F.W. All authors have read and agreed to the published version of the manuscript.  
Central Public-interest Scientific Institution Basal Research Fund, grant numbers S202305 and S202304.  
Not applicable.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Items** & \(\mathbf{X_{1}}\) **(m/s)** & \(\mathbf{X_{2}}\) & \(\mathbf{X_{3}}\) **(r/min)** & \(\mathbf{Y_{1}}\) **(\%)** & \(\mathbf{Y_{2}}\) **(\%)** \\ \hline Optimization solution & 0.30 & 12.34 & 815.44 & 87.95 & 8.83 \\ Verification solution & 0.300 & 12 & 815 & 82.55 & 9.57 \\ \hline \hline \end{tabular}
\end{table}
Table 6: The optimization and verification solutions.  
Data Availability Statement: The data presented in this study are available in the article.  
Conflicts of Interest: The authors declare no conflict of interest. The authors declare that this study received funding from Central Public-interest Scientific Institution Basal Research Fund. The funder had the following involvement with the study: [PERSON] and [PERSON].