Aug 15, 2021 · The emergy of the dies is given as follows: (11) E M m = ∑ i = 1 n t m i T m i × U m i × V c where U m is the monetary value of a die, T m is the lifespan of a die, and t m is the time-of-use of a die (the duration of contact between a die and a workpiece in relative motion), and i is the processing time. 3.3. Waste emergy