jurgen In this graduation project we had to investigate how to improve the production process to make it more flexible and improve the delivery reliability given that the demand in the market is uncertain and volatile

Current situation and the research project

For over 70 years, Ruma Rubber B.V. has specialized in the production processes of rubber. One of the departments of Ruma produces High Voltage cable accessories, used around the world to connect subsurface HV cables for electricity transmission and distribution.

Demand in this market is uncertain and volatile. It is not surprising that the demand pattern shows large peaks. Last year the delivery lead time increased extensively because the production process was not flexible enough to handle the large variation in demand. In this graduation project we had to investigate how to improve the production process to make it more flexible and improve the delivery reliability.

In our research it turned out that the capacity of the production process was too low to be able to guarantee the delivery times. In 2011 the utilization was 98% on a yearly basis. This is of course far too much, especially in a situation with large peaks in demand. In such situations delivery times already deteriorate at an average utilization above 80%.

Several improvement proposals to the capacity of the production process needed to be examined. To examine these proposals we applied simulation techniques, specifically the software package Enterprise Dynamics of INCONTROL Simulation Solutions.

Why simulation?

We chose to simulate each of the improvement proposals in Enterprise Dynamics because that made it easy to determine the capacity of each of the proposed situations. With only minor changes in the simulation model we could try out many different scenarios. This made it easy to determine which of the improvement proposals is best.

The production process also had many sources of uncertainty. In several steps of the production process large variation in the processing time makes it difficult to mathematically determine the capacity. This problem is solved with the use of simulation.


Using Enterprise Dynamics we finally examined the two improvement proposals that looked most promising in more detail. Using the models we determined the capacity on a weekly and monthly basis for each of these situations.

Eventually one of the proposals was selected by the management. In this proposal the capacity of the process increased with 46% against minimal investment costs (ROI=21 weeks) and minimal investment in extra personnel (two new production workers on a total of twenty). The improved production line is able to handle the demand.

Who worked on this project?

kevinThe students who worked on this project are Kevin James en Jurgen Gerristen. Kevin studied Industrial engineering and Jurgen studied Logistics and Transport Management both at the Hogeschool Windesheim Zwolle. Both followed the minor "Process optimization" where they learnt to apply simulation as a technique to improve business processes in general and in particular production and manufacturing processes.