Total Productive Maintenance (TPM) was first incorporated at DENSO CORPORATION in 1971. By 1982, Seiichi Nakajima had formally introduced Overall Equipment Effectiveness (OEE) to the world in his book, TPM tenkai (TPM Deployment). Originally, OEE sprang from TPM as a practical way to nurture equipment and help us become smarter maintainers. The dream was simple: empower local work teams to increase their knowledge and collectively solve problems to eliminate the six big losses.
But fast forward to today, and we might have lost it’s original purpose and essence.
The Metric Trap
In 2013, Nakajima defined TPM as “eliminating losses through the participation of all employees”. He drew a fascinating line, noting that while traditional industrial engineering focuses on eliminating “waste,” TPM insists we must eliminate “loss”.
But here’s the kicker: obsessing over a tidy OEE percentage on a dashboard actually distances us from that original, noble TPM purpose. As Michel Baudin brilliantly put it, the heavy emphasis on OEE is a distraction driven by “metrics-obsessed, Drucker-influenced managers and consultants”. Maintenance, much like human intelligence, cannot simply be reduced to a single number.
Dr. Wheeler completely agrees, advising that while you may use metrics for availability, quality, and performance separately, you should “resist the temptation to combine them”. The only practical way to use OEE is to bypass that combined score, break it down into its core factors (Availability, Performance, and Quality), and work directly on those. This gets us right back to the original TPM goal: genuinely involving all employees in making better use of equipment.
The Ultimate Irony: Overproduction
While Dr. Wheeler touches on the potential absurdity of the combined metric, he misses its biggest danger to lean manufacturing: overproduction.
Enter Hide Oba and his excellent post, “Why is OEE not necessary TPS?”. Oba warns that overproduction is a massive problem with OEE, because running large batches artificially raises your OEE score. This means an obsession with OEE can lead you to completely ignore Just-In-Time (JIT) principles, ultimately hurting your business.
https://www.hmoperationsmanagement.com/post/why-is-oee-not-necessary-tps
The bitter irony? The unintended consequence of misusing OEE might just be making your operations less lean at an increasingly fast rate.
📦 Standout Summary: The Main Takeaways
- TPM was born to eliminate losses through the participation of all employees, rather than just eliminating waste.
- Reducing maintenance to a single OEE percentage is a distraction; it’s much better to bypass the combined score and focus directly on Availability, Performance, and Quality.
- We need to resist the urge to combine these metrics and return to the original TPM purpose of involving local work teams in collaborative problem-solving.
📦 Standout Summary: Insights from Hide Oba’s Article
- Overproduction is a big problem associated with chasing OEE.
- Producing large batches just to raise your OEE score directly conflicts with JIT principles.
- Ignoring these lean principles for the sake of a high metric can actively hurt the business.
Let’s Chat!
Have you fallen into the OEE percentage trap? Are you looking to get back to basics and empower your teams without the vanity metrics?
Contact me directly or drop a comment below to discuss how we can make your operations genuinely lean, not just “metric-lean”! I’d love to hear your thoughts.