Abstract:
In the automotive industry, a Body-in-White (BIW) refers to the rst step, the basic structure,
in the production of a vehicle. Once a BIW production line has been built, the (maximum)
capacity is xed and throughput is therefore limited by the equipment speci ed during the
design phase. The main metric used to inform the production line design is the Net Ideal
Cycle Time (NICT). Unfortunately the state of practice to estimate the NICT is a basic
heuristic that does not account for production variation. In this paper we challenge the
current estimation approach by proposing an alternative that assumes actual production to
follow a Weibull distribution. The proposed model is derived and estimated from empirical
data. The results suggest that BIW production lines have traditionally been designed with
too low a capacity, resulting in planned throughput rarely being achieved. On the other
hand, increasing the design capacity implies higher initial investment. In this paper it is
demonstrated that the higher investment required is o set by reduced losses, resulting in
more reliable planning and returns.
