Tolerance Allocation Considering Multiple Phases of the Product Life Cycle for Optimum Cost, Performance, and Sustainability Using the HEIM Framework

Abstract

Tolerance allocation is usually considered only during the stages when designers are designing the product and manufacturing/process engineers are forming a process flow for the production. In this paper, the tolerances for a product are allocated by considering the most crucial stages of manufacturing, quality, use, and reuse stages of a product life cycle. This approach helps to sustainably allocate the tolerances. A framework characterized by attributes such as cost, performance, and sustainability, is discussed to achieve the intended tolerance allocation by considering multiple stages of the life cycle using the Hypothetical Equivalents and Inequivalents Method (HEIM). HEIM allocated the weightage to different parameters. In this case, HEIM is used to give weightage for different stages of the product life. This helps to allocate the tolerances with due importance to each stage. This is the main contribution of this paper, as the application of HEIM for tolerance allocation was not found in the literature. Extending this framework to products like mobile phones, laptops, watches, etc. would help to avoid the redesigning of the product in the future, making them more efficient in terms of cost, performance, and sustainability. Also, using this concept, products can be reused with liberalized tolerances while maintaining the same performance as new ones, leading to cost savings and improving the sustainability of the product. The proposed methodology has been applied in the present work to estimate the tolerances for achieving the least cost of manufacturing a product.