One of the easiest ways to improve capacity and decrease costs is to reduce equipment and process downtime. There can be many contributors to downtime, but from our experience, poor maintenance is the biggest culprit. All too often, we wait for something to go wrong instead of being proactive based on experience and historical data.
Total Productive Maintenance or TPM embodies a proactive approach. Data from the manufacturer, from past performance and from operator experience are gathered to define the parameters for preemptive actions to ensure that equipment and processes stay productive. TPM maintenance and replacement schedules are then set up to help eliminate downtime.
Two of the most powerful metrics of the productivity of a piece of equipment or a processing line are Overall Equipment Efficiency or OEE and Overall Process Effectiveness or OPE. The three components of these performance measurements are:
- Availability – Percentage of time the line/process is available to produce
- Efficiency – Percentage of what was produced against an agreed to standard
- Quality – The first pass yield percentage of the output of the line or process expressed as what the line or process ended up producing versus quantity at the start
These three percentages are then multiplied together to calculate OEE or OPE. Each discreet equipment, line or process should be calculated separately and the goal is to improve against the baseline.
Reducing downtime or increasing OEE is especially critical on equipment that is part of a Lean flow process. TPM manufacturing in a flow line dictates that downtime at a constraint will cause downtime throughout the line. If Herbie stops producing so does everything else!
