Maandelijks archief: september 2017

Ideas on maintenance

Before the industrial revolution, hardly any maintenance was carried out. Objects of use were usually produced as single pieces and were mostly designed on ‘run to fail’.

Later, maintenance consisted of a series of operations dictated to the user based on the manufacturer’s experience. Not all parts were designed with the same robustness. Some parts were more subject to wear and tear than others. The underlying idea behind that maintenance policy is that failure can be prevented or delayed. Especially for mass-produced goods it was and is possible to formulate generic maintenance rules. These rules are drawn up on the basis of average conditions of use. However, follwing these maintenance rules were no guarantee against failure. Often this failure was due to non or poorly maintained parts due to incorrect or incorrect material choices. Before the period of mass-produced consumer goods product were overdesigned, oversized and overdimensioned.

In the 1980s, the focus was on increasing the reliability of the various components of a composition. The sum of the reliability of a system was the result of the reliability of the individual components. Much effort was put into discovering and eliminating the weakest link in systems. If this was not possible, parts were redundantly designed. Maintenance activities focused in that days on increasing reliability. Later, attention was paid to the quality of the produced goods as indicators for maintenance efforts.

Today, perceptions about expected performance and presentation seem to shift slowly. In the case of maintenance, a balance has to be find between higher revenues due to better utilization of the assets on the one hand and maintenance costs on the other. The design, the materials used also affect the maintainability of an asset. In addition, the ‘licence to operate’ has to be taken into account, and regulations on the environment, safety and health are also increasing. The level of maintenance and its effectiveness depends on a lot of other factors: e. g. the availability of a sufficient number of trained staff, the availability of tools and spare parts and consumables. In addition, the operating conditions play an important role in the correct choice of a maintenance policy. Evaluation of choices of maintenance policy is difficult, sometimes before the end of the technical service life, a device needs to be replaced in favor for more advanced technologies. In short, there are (and were) different and shifting ideas about maintenance. Many of these are based on assumptions and short-sightness. Ideally, owners of capital-intensive assets should have a longer-term focus. Conscious choices in maintenance are often the result of a carefully chosen strategy. Maintenance must not longer regarded as a cost item.