The objective of this research is to introduce key performance indicators (KPIs) measuring overall equipment effectiveness (OEE) or overall operation effectiveness (OOE) effectively. OEE is one of the most effective KPI to measure the productivity and quality levels of an equipment-centric manufacturing company and widely implemented with a spreaded TPM (total productive maintenance). OEE is the most representative time-related KPI. For ease of measurement, OEE is calculated on the basis of the quantity of the processing materials and theoretical cycle time instead of using time-related sub-indicators. Hence, setting up theoretical cycle times is the most important aspect of the OEE measurement. Increasing customer's demand and developed manufacturing technology, more products can be made in a machine. So there will be multiple theoretical cycle times in a machine, but they have not been extensively considered for setting up theoretical cycle times in previous research. Futhermore the limitation to measure a performance of an operation which is consists of multiple machines is often mentioned in previous research. This paper shows how to measure OOE based on multiple theoretical cycle time.

Remarkably improvements have occurred recently in the maintenance management of physical assets and productive systems, so that less wastages of energy and resources occur. The technology of maintenance is about finding and applying cost-effective ways of avoiding or overcoming performance deterioration. Maintenance is thus a vital support function in business, especially as increasingly large investments are being required in physical assets. TPM(Total Productive Maintenance) focuses on optimizing planning scheduling. Availability, performance and quality rate are other factors that affect productivity. Especially there are some losses that affect the overall equipment effectiveness(OEE). These losses lead to low values of OEE, which provides an indication of how effective the production precess is. This study explores the ways in which Korean small and medium manufacturing industries can improve OEE.