Supporting maintenance strategies using Markov models

The basic principle of total productive maintenance (TPM) isto reduce and ultimately eliminate breakdowns by pre-emptivemaintenance strategies, which rely on the cooperation of allemployees. When properly applied, TPM can bring about tremendousimprovements in a company's performance. However, recent research,using interviews and questionnaires, suggests that many managersin manufacturing industries in Europe still have to be convincedof the usefulness of TPM. Many more are perhaps unsure of thelosses which can accrue as a consequence of not having an appropriatemaintenance programme implemented in their organizations. Asimple yet powerful Markov model is proposed as a diagnostictool for the manager who wants an effective way of identifyingthe prime costs involved in production line downtimes, and hencethe potential benefits of TPM. The influence of the performanceof a single machine on a line can be investigated. This is vitalinformation for strategic planning of machine replacements,which involve major capital investments. In particular, an approximateanalysis of the benefits of a machine building up a buffer stockis presented, and assessed against the costs involved. The modelhas been implemented as an Excel macro.