How to increase productive uptime and OEE

Ensuring efficiency and productivity by minimising downtime and reducing rejects is essential to increase the profitability of a production line. Beyond financial factors, increasing uptime helps boost sustainability credentials too.

The concept of overall equipment effectiveness (OEE) is considered the gold standard when it comes to calculating manufacturing productivity. It measures how well a manufacturing operation is running compared to its full potential.

An OEE score of 100% for example would mean a manufacturer is ensuring zero wastage, with no downtime, as fast as possible. Realistically, 85% is considered an ideal benchmark.

CALCULATING OEE

OEE is calculated by multiplying availability, performance and quality.

Availability is the ratio of run time to planned production time. It refers to how readily available equipment is according to its schedule. More specifically, it considers availability loss, including any events that significantly slow production, whether planned (e.g. changeovers) or unplanned (e.g. technical or operator issues).

Performance is based on how much waste is created when running at less than optimal speed. It takes into consideration anything that hinders the speed of production, from slow cycles to unexpected stops. Comparing the actual cycle times with ideal cycle times, performance ultimately highlights just how much production is lost by operating at less than ideal speeds.

Quality highlights how much time is lost by producing products that don’t meet quality standards. It compares how many good parts are made versus those which are defected – therefore the percentage of time being spent on products that meet specification.

PLANNING FOR THE UNPLANNED

Though these elements are essentially part of the OEE equation, they also highlight key considerations for manufacturers when it comes to general productivity.

Reducing reject rates is a key concern. The biggest challenge for many lies in understanding how to reduce downtime. Unplanned downtime, or unexpected issues, may be the first thing that springs to mind, but optimising performance to reduce planned downtime can also have a significant effect.