1. MAINTENANCE METRICS IN OEE
INTRODUCTION
In the manufacturing sector, world-over, machines have overwhelmingly taken over the
production of goods. Machines, as we all know, are subject to wear and tear, and if not
repaired timely, eventually, break down. To address the issue of maintenance
manufacturing firms would benefit by adopting TPM to monitor their machines’
performance and condition. The preventive metric of OEE can be used as a tool by the
management and workers to continually assess how well machines are serving their
owners, in real time, and determine action for repairs as and when required.
PREVENTIVE METRICS IN CONTEXT OF OEE
OEE or Overall Equipment Effectiveness, a performance metric quantifies the efficiency
of machines. It brings to visibility the entire factory floor, along with the machines and
2. the various production processes in the production lines. Before we set appreciate the
implications of preventive metrics, let first understand how an OEE system operates.
OEE provides digital data in the real time primarily by basing its calculation on 3 key
elements of production :
1. Availability = (Operating time – Downtime) /Total Operating Time
2. Performance = Total output/potential output
3. Quality = Good output/total output
The OEE system
The TPM metrics is derived from the study and analysis of data provided by OEE on
above 3 critical elements.
Advantages of the Preventive Metric
Reduces Downtime
One main feature of the OEE system that reflects TPM metrics is the Availability feature
which captures Operating time, Downtime and Total Operating time. In the process,
OEE helps in tracing a host of issues, including adverse machine conditions that cause
downtime. The issues can be detected at the individual level, a cell or line level, or the
whole plant level.
3. Tracing Equipment Fault in Real Time
The data provided by OEE reaches the minute levels of production processes, to show
where a machine is at fault. Once fault is found, appropriate action can be taken, and
thus, downtime be reduced. TPM metrics calls upon the unit to nip an equipment’s
problem at the bud stage, so as to prevent problems from aggravating in the future.
Reduces Repair Costs
Preventive metrics drastically reduces your repair costs. Without OEE, the faults of the
bigger and more complicated machines cannot easily be detected, more dso in real time.
An interface of OEE with CMMS ( Computerised Maintenance Management System )
further aids the TPM system to take preventive measures promptly. Timely repairs
could avert breakdowns causing downtime, and a significant loss for the firm.
The TPM metric could be checked from the Rate of Quality percentage as well. The rate
gives comparative statistics on the acceptable parts produced versus the scrap. Since the
preventive metric gathers data both at individual machine and line levels, it facilitates
detection of faults at its root.
Case Study
The benefit of the application of maintenance metric can be seen in the case of GE
Fanuc. The organisation had earlier sought to decrease its downtime duration by the use
of engineering processes. It was successful in its endeavour, but not satisfactorily. Later
when it switched over to OEE, GE application, the management detected plant’s
bottleneck area - hundreds of brief line stoppages due to simple misalignment causing a
dip in productivity were traced. Subsequently, when the firm took corrective measures,
production spiked.
CONCLUSION
When you have machines cranking out goods for your firm, don’t neglect their
well-being. The solution indeed is to keep a quantified vigilance over their efficiency and
4. productivity. And what better way to do so than using the maintenance metric under the
arc of the OEE system.
