Total Productive Maintenance (TPM)
What Is TPM?
TPM (Total Productive Maintenance) is an approach to maintenance that empowers operators with the expanded responsibility of integrating equipment maintenance into the manufacturing process. The goal of any TPM program is to eliminate losses tied to equipment maintenance or, in other words, keep equipment producing only good product as fast as possible with no unplanned downtime. We like to refer to this as “perfect production”. TPM takes a proactive approach to maintaining and improving equipment as opposed to a typical reactive maintenance process.
TPM in Lean Manufacturing
Maintenance has traditionally been viewed as a separate entity outside of the manufacturing process. However, as companies began to identify the role of maintenance in the production process, a gradual shift in thinking occurred. Total Productive Maintenance emerged out of the need to integrate maintenance with manufacturing to improve productivity and asset availability. The culmination of change from a reactive/corrective maintenance environment to one that is based on prevention through predictive maintenance is the process of TPM.
TPM is used to drive waste out of the lean manufacturing process by reducing or eliminating production time lost to machine failures. The goal of any TPM program is to ensure that machinery and equipment is always available to manufacture products for the end customer. By minimizing rework, slow running equipment and downtime, maximum value is added at the minimum cost.
Successful TPM is a group effort where the entire organization works together to maintain and improve the equipment. One of the first steps in implementing TPM is forming teams that are empowered to improve the process. Flattening the organizational structure enables teams to address issues when they have the greatest impact – when they occur. As employees join TPM teams, operators are trained to perform routine maintenance items and assume an ownership role. Employees empowered to affect the process will typically be in a position to identify and create process improvements that would have normally been overlooked by management. An on-going refactoring of the process provides a method to implement improvements.
As maintenance issues are addressed and total productive maintenance programs implemented, the true value of TPM begins to emerge. Just as lean manufacturing relies on Kaizen or continuous improvement; continuous re-evaluation of the maintenance cycle allows for Kaizen in maintenance programs. Root cause analysis exposes the underlying issues to be addressed. By addressing issues at the root level, problems can be eliminated.
As with any lean initiative it is critical to measure change. OEE (Overall Equipment Effectiveness) is a metric originally developed to measure the success of total productive maintenance programs by associating the Six Big Losses with three measurables: Availability, Performance and Quality. OEE enables organizations to benchmark and monitor their progress with simple, easy to understand metrics. OEE provides both a gauge for the success of TPM and a framework to identify areas that can be improved.
Here is an easy way to relate Total Productive Maintenance to each OEE Factor. TPM can improve OEE Availability by preventing machine breakdowns, thereby reducing downtime. OEE Performance can be improved through TPM by keeping machinery in top condition, preventing slow cycles and small stops. Finally, continually fine-tuning equipment, including optimizing running speed, minimizes the potential for defective parts, increasing OEE Quality. Remember not to aim for a specific OEE score, but instead, to focus on incrementally improving your OEE score over time.
Benefits of TPM
Equipment maintenance is a fact of life. Companies that understand this and use TPM to get the most out of their resources will typically see the following top three benefits:
- Significantly decreased maintenance costs
- Increased equipment availability and profitability
- Improved teamwork and employee involvement
TPM makes it much easier for companies to focus on prevention as opposed to reaction. It provides the tools to turn maintenance programs into a competitive advantage.
1. Significantly Decreased Maintenance Costs
Maintaining equipment can become expensive, especially as it ages. However, it is much more expensive to fix a neglected machine that breaks down than it is to proactively maintain it to prevent breakdowns in the first place. By focusing on preventative maintenance, TPM reduces maintenance costs in the long-run.
2. Increased Equipment Availability and Profitability
One of the goals of Total Productive Maintenance is to strive for perfect production. A large part of TPM is an ongoing focus on keeping equipment in good condition, which reduces small stops and downtime while increasing profits. Beyond the efficiencies in cost gained from eliminating slow and stopped processes, TPM emphasizes producing only good parts. A decrease in defective parts that would have otherwise been scrapped or sent back for rework directly translates to a reduction in costs for the manufacturer. The best part? All of this is accomplished without additional expenses beyond small increments of time spent by current employees.
3. Improved Teamwork and Employee Involvement
Engaged employees do better work. By empowering plant-floor employees to make improvements through the TPM process, they will be more motivated to do well in other aspects of their job. This usually translates into process improvements beyond those directly related to TPM (higher quality parts, less down time, reduction in machine breakdowns, etc.) such as hitting or even exceeding shift targets.
