Production Planning
The downtime is the cost everyone books. The recovery curve is the cost nobody does.
— %
At this point on the recovery curve
A target efficiency at or above the steady rate is unreachable and the units-to-target figure will run to infinity or return no answer — the curve approaches the steady rate asymptotically and never crosses it. The half-life must be fitted from your own hourly output records after real changeovers; it varies enormously with how similar the new style is to the old and with whether the same operators keep the same operations. Production lost is measured against the steady rate as though the line could have run at it from minute one, which is the right comparison for judging changeover frequency and the wrong one for judging the operators.
Multi-Style Line Changeover Penalty & Recovery Curve — free, with the formula and a worked example, at Textile School.