Example of a master thesis project: Mike Grolleman at DAF

Research theme Production Management

Research title Batch Size Decisions in the DAF Supply Chain

Researcher Mike Grolleman

Research period From August 2011 to March 2012

Supervisor Sipke Hoekstra


This master thesis project is about the subject “Batch Size Decisions in the DAF Supply Chain”. At DAF Trucks Eindhoven the CF and XF truck models are assembled. The supply chain in this study consists of a sheet metal component plant, a paint shop with two warehouses for unpainted and painted parts, a central warehouse and an assembly plant. The sheet metal component plant prefers large batch sizes due to high machine setup times. The assembly plant requires small batch sizes and hence a low inventory level derived from the lean philosophy and due to a limited floor space. It is unknown which batch sizes result in the lowest costs for the total supply chain.

Sheet metal component plant Assembly plant


A supply chain batch size model was designed in Excel. This model should support the material planners in their batch size decisions by providing insight in the batch sizes that minimize the total supply chain costs. A macro is programmed where the optimization can be performed for a set of multiple items.


The results show that the optimized batch sizes are on average a factor 3.7 higher for the sheet metal component plant and a factor 2.3 higher for the paint shop compared to the current applied batch sizes. The optimized batch sizes would decrease the current annual total supply chain costs with 31.8%.

Personal experience

It was very interesting to translate the characteristics of a complex production environment into a mathematical optimization model. Furthermore analyzing business processes is very interesting since you learn a lot about the whole company.