ORiON

Editorial to Volume 37(1)

Jaco Visagie — 2021-06-29

Estimating net ideal cycle time for body-in-white production lines

Willem C. Grobler — 2021-06-29

In the automotive industry, a Body in White (BIW) refers to the first step, the basic structure, in the production of a vehicle. Once a BIW production line has been built, the (maximum) capacity is fixed and throughput is therefore limited by the equipment specified 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 a higher initial investment. In this paper it is demonstrated that the higher investment required is offset by reduced losses, resulting in more reliable planning and returns.

Vehicle routing decision support for a local retailer

Jan H van Vuuren — 2021-06-29

One of the most challenging decisions that has to made routinely by dispatch managers at distribution centres of warehousing and distribution businesses in the retail sector involves the assignment of delivery vehicles to service customers exhibiting demand for retail goods and the subsequent routing of these delivery vehicles to the various customers and back again. Perhaps surprisingly, these dispatch managers do not always use vehicle routing software to schedule goods deliveries to customers, instead often relying on teams of human schedulers who perform this task manually. The reason for not using such software is usually a perception that it may be difficult to integrate the software with existing enterprise resource planning systems already in use. In such cases, estimates of potential costs savings that may be brought about by such software is often required before the dispatch department will risk the significant step towards investing in vehicle routing planning software. Dispatch managers may then employ these cost savings estimates in cost-benefit trade-off analyses. This paper contains a practical case study in which the potential cost savings of a vehicle routing optimisation approach are quantified for a large retail distribution centre in the South African Western Cape in a bid to support its decision as to whether or not to invest in vehicle routing planning software.