t_n = t_1 x (n) to the power (r)
where t_n = time to complete the n th unit,
t_1 = time to complete the first unitr = natural log (learning ratio)/ natural log (2),
where learning ratio is for eg. 0.9 for 90% learning, 0.8 for 80% learning and so on ..
Does it imply that as the cumulative numbers increases, the time required to manufacture the units approach zero ?? Not at all.
The time required to manufacture each additional unit is negative exponentially distributed. (as given in the curve). As the cumulative numbers increase, the time needed to manufacture each additional unit approaches a theoritical minimum, which is the standard time required for the production of the unit. The magnitude of the incremental time taken for manufacturing each additional unit decreases as we manufacture more units.
When we say there is a steep learning curve, it just implies that after the first few units, the learning is very fast. A flat learning curve implies that the learning on the job is very slow and takes lot of time.
This helps companies to competitively bid for complex products, as the cost it takes to manufacture multiple units of complex parts decreases as the volume increases (a steep curve indicates costs to manufacture future components will be much less than the time to manufacture earlier components while a less steep curve indicates the drop in time to be less..)