Tolerance optimization using the Lambert W function: an empirical approach

This paper explores the integration of the Lambert W function to a tolerance optimization problem with two unique features. First, the Taguchi loss function has been a popular tool for quantifying a quality loss incurred by the customer. This paper utilizes an empirical approach based on a well-established regression analysis, which may be more appealing to engineers and better capture the customer's perception of product performance. Second, by trading off manufacturing and rejection costs incurred by a manufacturer and quality loss incurred by the customer, this paper shows how the Lambert W function, widely used in physics, can be efficiently applied, which is perhaps the first attempt in the literature related to tolerance optimization and synthesis. Using the concept of the Lambert W function, this paper derives a closed-form solution, which may serve as a means for quality practitioners to make a quick decision on their optimal tolerances without resorting to rigorous optimization procedures using numerical methods. A numerical example is illustrated and a sensitivity analysis is performed.