Dynamic manufacturing costs—Describing the dynamic behavior of downtimes from a cost perspective

Downtimes in a manufacturing cell, a production line or an individual machine are characterized by a complex statistical behavior that their frequency and duration display. The work reported here concerns likenesses and differences between various statistical distributions that apply to functional times (TBF) and downtimes (DT) in connection with different discrete manufacturing processes. The TBF and DT are viewed as varying over the whole production time for the batch. A method is presented for analyzing the dynamic behavior involved in terms of costs. An important element in this method is the statistical analysis of downtimes, making use of both empirical and theoretical distribution functions that apply to functioning times and downtimes of specific types. For demonstrating how the method is employed, use is made of real data obtained from the Swedish company Alfa Laval.