Capital goods such as advanced medical systems, baggage handling systems, advanced printing systems and lithography systems are highly complex and customer-specific products, typically assembled or engineered to customer specification. After delivery and installation at the customer site, the customer uses the product for many years, during which the product is maintained and possibly upgraded. Unplanned downtimes generally have a large effect on the primary processes of the customers, and therefore high system availabilities are required.
In general, it holds that the higher the required system availability level is, the higher the maintenance costs will be. Another way to increase the availability level is by making changes in the design of the capital good, which lead to a change in the acquisition cost, or future maintenance cost. In other words, there is a trade-off. Increasing availability or decreasing downtime on the one hand, normally increases Total Cost of Ownership (TCO) on the other hand and vice versa. The mission of research within our research line Maintenance Operations and Reliability Engineering is to break through this trade-off. In other words, to improve the service level, whilst simultaneously reducing total cost.
We distinguish three research themes, all of which are directly related to reducing the downtime of capital goods.
•Design and control of service supply chains
Within this theme, we consider the worldwide networks in which spare parts and service engineers are positioned to support corrective maintenance actions. Through this theme, we aim to influence the maintenance delay.
This theme includes the trade-off between preventive and corrective maintenance, the monitoring of machine performance and the application of condition-based maintenance. Through this theme, we aim to influence the number of failures and maintenance delay.
•Design for availability
Within this theme, we study the design of a capital good from the perspective of availability or downtime. The focus is on finding techniques that increase the total availability of a machine and we quantify their effect in terms of TCO. Through this theme, we aim to influence the number of failures, the maintenance delay and the repair time.
Over the last couple of years we have had a significant impact on both scientific and industry levels. In our research projects, we closely cooperate with several companies, among which: ASML, DAF, IBM, KLM Maintenance, NedTrain, Océ, Philips Healthcare, Marel Stork and Vanderlande Industries. These collaborations led to important scientific insights, and simultaneously reduced the costs of the companies involved. An example of this is a joint research project with ASML in which we developed a partial pooling concept. Through a case study we showed that both downtime and costs could be reduced drastically. This concept has been implemented by ASML, and had the predicted impact, leading to major cost reductions. Recently, this concept was extended to a more general concept that includes the planning at the central warehouses. Based on the partial pooling concept developed for ASML, we developed a similar concept for the car stocks and quick response stocks at Océ Technologies. Here again we found important improvement opportunities. Also this study was followed by an implementation in their practice.