Equipment or, for that matter, any physical asset in our plants and facilities is generally expected to be efficient and effective. In other words, it’s expected to do what it was designed to do under defined operating conditions for specified periods of time. It doesn’t seem like we’re asking too much: RCM (reliability-centered maintenance) focused on improving equipment maintenance with a generally accepted definition of efficiency and effectiveness.
Another, broader perspective of equipment efficiency and effectiveness, however, also deserves our consideration. This concept was introduced in the 1980s with the concept of Total Productive Maintenance (TPM).
When TPM hit U.S. shores in the mid to late ‘80s, it was supposed to help us develop organization-wide work cultures for improving equipment effectiveness. The five basic, interdependent “Pillars of TPM” defined principles that made the process work. Coupled with the Theory of Constraints, those principles should have launched a paradigm shift in equipment-performance improvement. In fact, in 1990, I was constantly insisting that TPM would become the predominant equipment-effectiveness strategy of the 21st century. Little did I realize it could become so de-constructed that it would no longer represent an effective business-improvement process.
What changed? TPM’s intent of improving equipment effectiveness devolved into the widespread practice of “operator care.” [Specifically, the Autonomous Maintenance (AM) model for training turned into yet another spin on operator care as being synonymous with TPM.]
As guided by the first Pillar of TPM, the “focused-improvement” principle morphed into a calculated metric of Overall Equipment Effectiveness (OEE). In turn, OEE launched itself into a mega-metric, well beyond its intended use to compare a machine to itself over a period of time.
Of the original five principles (Pillars) of TPM, two were widely embraced by many implementations: operator care/autonomous maintenance and OEE-percentage. Much to my dismay, this reality debunked my previously mentioned “predominant equipment-effectiveness strategy” prediction. Unfortunately, operator care and OEE do not define true TPM.
But it’s not too late to learn from TPM. Given industry’s skilled-worker shortages, demand for significantly improved equipment performance and reliability, and dependence on rapidly growing new technologies, true TPM will be the answer, whether labeled “TPM” or not.
Consider TPM’s expressed aim to improve equipment effectiveness by engaging the entire organization. The first Pillar, “improving equipment effectiveness by eliminating the (six) major losses,” led to a growing list of such losses (or causes of poor performance). The bottom line is that the starting point for TPM-based improvements is the identification of the problems to be eliminated.
Let’s explore those two foundational principles: eliminating the major losses and engaging the entire organization. Improving equipment effectiveness begins and ends with them (and all remaining Pillars of TPM rely on them.)
What gets measured gets done
Building on the original TPM teachings of the Six Major Losses, let’s jump into what I refer to as “actual equipment losses.” Identifying them is central to improving equipment effectiveness, as well as to getting organizational buy-in and ownership of root causes and sustainable corrective actions.
The accompanying diagram was developed for a client organization to help personnel recognize metrics and measurements that must exist as a foundation for improving bottom-line business performance, as well as help in deploying plant-floor business-oriented metrics in critical bottleneck areas.
Equipment capacity losses
Because the plant-improvement project focused primarily on improving production flow through the manufacturing processes, it was important to understand Equipment Capacity. A fundamental re-definition was necessary since the site had historically linked the concept to standard production rates. Downtime was treated separately, and in very general terms.
Basic equipment capacity was ultimately defined as the design capacity or historical best. Capacity Utilization losses occur when plant leadership makes a conscious decision to not run the equipment. Consider these losses “Planned,” as shown in the diagram.
Equipment utilization losses
Losses occurring when equipment is scheduled to run are categorized in the diagram as Equipment Utilization losses. As shown, some of them, i.e., Unplanned Downtime, Efficiency, and Yield losses, are straightforward. Setup/Changeover losses, though, can be planned or unplanned.
Setup/Changeover losses occur as Planned when those actions are accomplished properly, in the designated timeframe. When setups/changeovers are not completed within the planned timeframe and/or not performed properly, they should be categorized as Unplanned Downtime losses.
While the literature is rich with standard terms for equipment-related losses, there’s a significant advantage in leveraging terminology that is commonly used at a site. The diagram shows a combination of traditional definitions used around the client’s operations, with the addition of new loss descriptions: No or Defective Material, No Operator, and the granularity of three Yield losses.
Material: All bottleneck equipment in the plant depended on material flow to the machine. Unplanned Downtime should be captured whenever material is not available or when it’s damaged or incapable of being run at acceptable rates.
No Operator: Occasionally, some of the plant’s most critical equipment couldn’t be operated due to the absence of a skilled operator. Regardless of the reason, these incidents are logged as a type of Unplanned Downtime: No Operator.
Yield & Waste: Yield losses have a negative impact on planned flow through the equipment and the rest of the plant. The site is now tracking three types of them as part of its flow-improvement project and a separate waste-reduction initiative.
Product Rework losses have a triple impact on the business, i.e., waste of materials, unproductive machine time, and the cost of committing additional labor and machine time to rework the defects or sort the good items from the bad items.
Despite the amount of actual material waste being created, the plant didn’t historically capture materials lost due to equipment Startups and/or Setups (including Adjustments). This type of loss also contributed to inaccurate inventory downstream, leading to additional small lot re-runs.
Tapping the hidden factory
Plant-floor employees and senior management, and all those in between, should be able to understand the impact of equipment-related losses that have a direct line-of-sight to business goals and objectives.
Tracking Equipment Effectiveness losses and then focusing on eliminating the impact of the “critical few” depends on a collaborative effort that begins with equipment operators. Engaging them and the Operations leadership team in loss-elimination efforts is not only a key component of TPM, it’s an essential element of any reliability-improvement initiative. MT
Bob Williamson, CMRP, CPMM and member of the Institute of Asset Management, is in his fourth decade of focusing on the “people side” of world-class maintenance and reliability in plants and facilities across North America. Contact him at RobertMW2@cs.com.