## 5 Conclusions, Limitations, and Future Research  
Intending to boost overall product competitiveness, this investigation developed a comprehensive methodology for the design decision making of machine tool product families. The research process adhered to a sequence of \"model construction-model validation-system evaluation\". The primary innovations and conclusions are as follows:  
(1) The study harnessed the PFA theory as a data collection tool, validated the model using SEM, and conducted comprehensive assessments through path load normalization and AHP subjective weighting. Ultimately, this decision-making method was applied to the practical styling design of Heatking quenching machine tools, ascertaining the scientific validity and feasibility of the proposed evaluation approach. (2) By exploring the correlations between various weighting methods, such as AHP, entropy weighting, and SEM path coefficient normalization weights, and actual assessments, this research provided valuable insights for different application scenarios. This is conducive to obtaining more scientific and objective support for design decisions in the era of Industry 4.0, hence meeting personalized consumer demands. This paper, starting from the perspective of design decision-making methods, compared commonly used weighting methods and established design paradigms. It integrated the PFA theory as a tool for guiding requirement collection and employed SEM, grey weighted comprehensive evaluation, and subjective weighting methods as tools for evaluating indicators. It innovatively constructed a scientific decision-making approach following the sequence of \"model construction-model validation-system evaluation\". In the evaluation of weighting schemes, it creatively utilized the SEM normalization algorithm and combined it with the traditional subjective weighting method AHP. This approach fully considered expert opinions while also taking into account the extent of each indicator explaining latent variables. Furthermore, this investigation compared this decision-making method with the widely used comprehensive subjective-objective weighting method entropy weight-TOPSIS. Both methods yielded similar core design component rankings. Nevertheless, the decision-making approach proposed in this paper can better prevent the issue of sensitivity to outliers that is common with objective entropy weighting methods. Through the aforementioned steps, the theoretical validity of the design decision-making approach was thoroughly verified. Ultimately, this approach was applied to the industrial styling design practice of quenching machine tools. It leveraged expert opinions to identify multiple design improvement points, including industrial styling, CNC interfaces, and man-machine interaction, effectively assisting in design optimization and enhancing the overall competitiveness of machine tool products. Machine tool industrial design is a complex field that requires consideration of multiple factors. The framework proposed in this study may not encompass all influencing factors, and adjustments may be necessary in practical applications to meet the specific needs of different companies and projects. Secondly, the industrial design field evolves rapidly, and the results of this study may become outdated relatively quickly. It is important to stay up to date with the latest industry trends, continually enrich and update the content of methodologies, and remain synchronized with technological developments. Furthermore, this study primarily focuses on machine tool styling, while other product categories may require additional preliminary research to obtain relevant design criteria. Subsequent research can expand the range of applicable products and enhance the universality of methodologies. Lastly, the era of Industry 4.0 presents new challenges and requirements.