Product family design optimization considering manufacturing and assembly process costs

Simultaneous optimization of a family of related products can yield significant benefits compared to individual product optimization. Standardization of parts across different products and streamlining assembly and manufacturing processes can lead to reduced overall costs for the product family. In this study, we introduce a methodology for optimizing the design of a product family while considering detailed CAD models of individual products. The motivation arises from the challenge of achieving optimal product standardization without compromising individual product performance. Existing methods often impose predefined levels of commonality and seldom account for detailed CAD models and computationally expensive metrics of interest. To address this gap, we propose a novel approach that utilizes surrogate models to mitigate computational complexity and optimize the product family configuration based on total production cost, ensuring economically viable configurations while meeting performance requirements. The objective function incorporates the total production cost of the product family, including manufacturing and assembly process costs and volume discounts. Assembly process complexity and associated costs are quantified using Design for Assembly rules, while individual product performance, evaluated through finite element models, serves as a constraint. The results of the single-objective optimization, applied to a case study involving a product family comprising multiple gearboxes, demonstrate that by considering the product family, a better design in terms of the total production cost can be found compared to optimizing each product individually. Results indicate that the suggested method can efficiently identify optimal product family configurations, balancing standardization benefits with individual product performance. Overall, this study contributes to advancing methodologies for product family optimization and underscores the importance of considering detailed product designs in the optimization process.