Basics of Lean Maintenance

Basics of Lean Maintenance

When properly applied to maintenance processes, lean strategies can remove waste and improve equipment performance.

Can a manufacturing operation truly be "lean" without applying lean strategies to equipment maintenance? Experts answer that question with a resounding "no."

In their book "Lean Maintenance: Reduce Costs, Improve Quality and Increase Market Share," authors Ricky Smith and Bruce Hawkins assert that manufacturers cannot achieve the maximum benefits of lean without applying it to their maintenance operations.

"Typically on the factory floor there are buffer stocks between manufacturing steps. And one of the goals of lean is to reduce these dramatically or eliminate them altogether," Hawkins tells IndustryWeek.com. "But those buffer stocks often serve to insulate or provide insurance against equipment downtime. And if the equipment is not reliable, then when one manufacturing operation step goes down, the subsequent steps also go down."

When that happens, Hawkins adds, the common refrain is: "We need maintenance to fix the equipment faster."

Bruce Hawkins: "Fast repairs is not the answer."

"Well, fast repairs is not the answer. The answer is don't let it fail in the first place," says Hawkins, who is director of field operations for the Southbury, Conn.-based Management Resources Group Inc. "So do the necessary targeted maintenance to ensure that the assets are reliable, and then you can get the benefit of lean manufacturing."

Hawkins concludes: "[Equipment] reliability is a prerequisite to a full lean implementation."

Maintenance consultant John Kravontka, president of Manchester, Conn.-based Fuss & O'Neill Manufacturing Solutions LLC, agrees. Kravontka observes that maintenance personnel often are the last to know about lean initiatives, and "in some plants they actually end up moving equipment and doing all sorts of stuff and don't know why."

In his consulting work with manufacturers, Kravontka finds that overall equipment effectiveness (OEE) rates typically hover around 50% or lower and maintenance departments "are stuck in what we call the 'breakdown mode.'"

"If they had 100 maintenance jobs, 80 to 90 would be fixing [broken equipment] and maybe 10 or so would be doing something proactive," Kravontka says. "They're stuck in that mode, and it's difficult to get out of."

Kravontka asserts that in many manufacturing plants, not much has changed since he started out as a machine tool maintenance apprentice at the age of 19.

"When I got out of the apprenticeship, our department was called 'Machine Repair,'" Kravontka says. "So right away that told you what our job was -- to repair and fix equipment. We did it well and we were rewarded for it. But it was not what we were supposed to be doing."

What Lean Maintenance Is -- and Isn't

To get out of what Kravontka calls the breakdown mode, he and other experts recommend applying lean tools to the maintenance process.

At its core, lean is about removing waste from manufacturing processes. With that in mind, Joel Levitt, a Lafayette Hill, Pa.-based maintenance consultant and author of another book titled "Lean Maintenance," defines "lean maintenance" as "delivery of maintenance services to customers with as little waste as possible, or producing a desirable maintenance outcome with the fewest inputs possible."

In his book, Levitt lists 10 maintenance inputs:

  1. Labor
  2. Management effort
  3. Maintenance parts, materials and supplies
  4. Contractors
  5. Equipment rental
  6. Service contracts
  7. Raw materials
  8. Energy
  9. Capital
  10. Overhead

In his book, Levitt notes that formal definitions of lean characterize the philosophy "as the elimination of everything in the value stream that does not provide added value to the customer or to the product." Levitt points out that the maintenance value stream "includes the work request or notification, the work order, job planning, coordination, scheduling, execution and communications." Subsidiary streams such as material management flow into the main stream, Levitt adds.

"Within the value stream there's a flow from step to step," Levitt wrote. "Our goal is to provide maintenance services without waste or waiting."

How a manufacturer defines the concept could be a hindrance to a successful implementation of lean maintenance. Levitt notes that some lean manufacturers fail at implementing lean in their maintenance processes because they view it simply as a cost-cutting tool.

"So they say lean maintenance is getting rid of half of the stuff in the storeroom," Levitt tells IndustryWeek.com. " ... Reducing waste leads to cutting costs, but cutting costs does not always lead to reducing waste."

Joel Levitt: "Reducing waste leads to cutting costs, but cutting costs does not always lead to reducing waste."

Levitt notes that "the leanest scenario is when your predictive programs are so powerful that nothing ever breaks without giving you adequate notice or the equipment is so robust that it doesn't break at all." But that doesn't jibe with reality. Consequently, he emphasizes that having an inventory of "critical spare" parts is not necessarily waste.

"Not having critical spares when you need them is way 'fat,' and in terms of consequences, much worse than having stock you don't use," Levitt tells IndustryWeek.com. He adds that having critical spares on hand reduces downtime, enables maintenance worker productivity, boosts safety (by reducing maintenance worker "improvisation") and improves mean time between failures by using the appropriate OEM parts -- all of which are congruent with the lean philosophy.

In some plants, senior leaders have used the term "lean" as a euphemism for downsizing, Kravontka points out.

"They say, 'Hey we're going to lean out the plant.' What they're really telling everybody is, 'We're going to lay off,'" Kravontka says. "So when some plants hear the word 'lean,' their antennae go up."

That's one reason why Kravontka prefers the term "maintenance excellence" over "lean maintenance."

"Because that's what we really want to get to," he says. "We want to get to the point where 80% of all of our work is planned and proactive in nature. When we do that, we're going to be adding a lot of value to that equipment. It's going to be running at a high level, and maintenance is going to be viewed as a department that does that."

Common Lean Tools Applied to Maintenance

Whether you call it lean maintenance, maintenance excellence or something else, there are a number of lean strategies that, when applied to maintenance processes, can remove waste -- and improve OEE rates and other metrics such as safety, quality and productivity.

Those lean tools include:

  • 5-S -- The 5-S process is a way to remove clutter and organize the workplace so that "what is needed to do a job is near at hand," Levitt points out in his book. While 5-S originally was not intended to be applied to maintenance, Levitt notes that the methodology "has been transposed into maintenance because the things that make it valuable in production are the same things that make it valuable in maintenance." The 5-S process is based on five steps, which, translated from Japanese into English (translations tend to vary), are: sort, straighten, shine, standardize and sustain. Some lean practitioners add safety to the list and refer to this system as "6-S."
  • Kaizen events -- A kaizen event is a short-term, team-based lean effort focused on improving a specific process or area. Adil Dalal, founder and CEO of Pinnacle Process Solutions International, Cedar Park, Texas-based company, asserts that kaizen events applied to maintenance-related processes can yield impressive results. For example, Dalal says one of the kaizen events he led was a weeklong event at a major oil and gas company that reduced the setup for a CNC machine from an hour to about 12 minutes. According to Dalal, kaizen events applied to machine changeover include training; videotaping the changeover and reviewing it; identifying and separating internal setup steps and external setup steps (external setup are steps and procedures that can be completed while the machine is operating). The teams then try to apply practical solutions to reduce or eliminate both the internal and external setup steps. Regarding the last point, Dalal emphasizes that it's not about throwing money at the problem by purchasing new equipment or applying cycle-time reduction tools such as a single-minute exchange of die. "We're saying, 'How can we use our creativity, actually solve that problem and implement the solution which will completely transform the process, resulting in efficiency, ergonomic and financial gains? '" Dalal explains.
  • Value-stream mapping -- In a presentation at the 2010 Best Plants Conference in Cleveland, Bruce Hawkins defined value-stream mapping as a tool to "scrutinize the existing work process flows for non-value-adding activities" such as redundant steps, loopbacks, wasted effort and unnecessary queues. The process involves removing all non-value-adding activities or developing value-adding workarounds, and creating a "future-state" process. "Typically the maintenance function starts at receiving a request for work and ends at closing the work out and making sure the equipment history is documented," Hawkins tells IndustryWeek. "From the cradle up front to the grave in the back, there are a ton of opportunities to waste time and resources."
  • Standardized workflow -- As detailed in Hawkins' Best Plants presentation, standardized workflow entails creating standard work processes for each of the three types of maintenance work: system-generated PM (preventive maintenance) work orders; unplanned emergency/urgent (reactive) work orders; and plannable work orders (backlog).
  • Mistake-proofing -- Applied to maintenance, mistake-proofing (or "poka yoke" in Japanese) might include: creating sufficiently detailed job plans; providing detailed quantitative PM procedures; using bills of material in the CMMS (computerized maintenance management system); color coding lubricants; using different-style connectors on utility hoses; labeling all equipment with an equipment ID number; and implementing an effective management-of-change process, according to Hawkins.

A Few Prerequisites

While these lean tools can have a significant impact on the efficiency and effectiveness of a plant's maintenance processes, there are several prerequisites for a lean maintenance initiative to be successful, Hawkins asserts. For example, "there's a very strong need to have a fully implemented computerized maintenance management system in order to both manage the work and to capture the data necessary to make continuous improvements," he explains.

"A big part of [Management Resources Group's] business is going in and helping re-implement these things, because people have taken shortcuts on the initial implementation," Hawkins says. "They've not put all the asset data in there. They've not created bills of materials to link their material items to the equipment. They typically have not done any type of ranking of criticality of the equipment, so they really don't know which is more important than the other. They typically haven't done a thorough job of implementing PM procedures."

Also, "many organizations tend to just accept the manufacturers' recommendations as the basis for their preventive maintenance programs," Hawkins laments. While "sometimes it's OK to do that," he cautions that their recommendations should be taken with a grain of salt.

"No. 1, [the OEMs] want to make sure the equipment lasts through the warranty period, so typically they're going to be very, very conservative when it comes to those requirements," Hawkins says. "The second issue that we find a lot is that the OEMs will tend to recommend component replacements on a time-directed frequency, and of course they're in the business to sell spare parts as well.

"What we prefer is to use a scientific method such as failure-modes-and-effects analysis or reliability-centered maintenance analysis to identify first the ways in which the equipment is expected to fail and then target specific maintenance actions at those potential failures."

Hide comments

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish