Lean for Machines

Lean for Machines

Applying continuous-improvement strategies to maintenance can help your plant run like a well-oiled machine.

Before General Cable Corp. began its lean journey about a decade ago, Mark Thackeray, senior vice president for North American operations, says the company's maintenance personnel were kind of like firefighters -- responding to equipment breakdowns as quickly as possible.

But now that the Highland Heights, Ky.-based manufacturer of wire and cable products has implemented lean strategies at many of its North American plants, Thackeray notes that the company has shifted from a "reactionary maintenance" mode to a "preventive and predictive maintenance" focus.

"[W]hat we've changed in our philosophy about maintenance in the lean environment is you have to be much more involved and proactive in ensuring the reliability of machines instead of running to the problem when they're broken down," Thackeray explains.

Carlos Garcia conducts an analysis of overall equipment effectiveness (OEE) at General Cable's facility in Des Plaines, Ill.

Another shift since General Cable embarked on its lean journey in North America has been the company's effort to squeeze additional output -- or "entitlement capacity" -- from its existing equipment rather than buying new equipment when plants reach full capacity. To achieve this, the company has focused on improving its overall equipment effectiveness (OEE), a measurement that shows the percentage of time that equipment, when running or required for production, is producing good-quality products at current rate (or speed) compared with theoretical maximum rate. (OEE is calculated by multiplying uptime rate by production rate by first-pass quality rate.)

"Here we look to maintenance as a key stakeholder in improving the uptime leg of the OEE metric, and finding us additional capacity without spending money on machines," Thackeray says.

General Cable has implemented a number of continuous-improvement strategies to pursue its maintenance objectives, including investing in a formal computerized maintenance management system (CMMS). Through its CMMS, General Cable can track equipment breakdowns, schedule preventive maintenance activities, anticipate its needs for maintenance parts and automatically issue purchase orders before machine maintenance work is performed, according to Thackeray.

"That has helped us to be much more compliant in work-order completion," Thackeray explains. "It's allowed us to schedule the time we need to maintain our machines in a preventive mode instead of running them to failure, without disappointing customers on work orders. And it's allowed us to minimize our investment in MRO [maintenance, repair and operations] inventory, yet still have better uptime on machines."

Thackeray notes that maintenance personnel are embedded with plants' natural work teams, a departure from the "old traditional factory" days when "maintenance was a very prized set of skills tucked away in the corner." Having maintenance and production personnel co-located not only has had an impact on OEE rates but also on metrics such as safety.

"Here we look to maintenance as a key stakeholder in improving the uptime leg of the OEE metric, and finding us additional capacity without spending money on machines."
-- Mark Thackeray, senior vice president, North American operations

"So rather than having maintenance in a separate corner of the building, we like maintenance to actually have their location in the cell, in the value stream -- we like their toolbox to be front and center of the cell -- and for them to be part of that work team that has ownership of the mini factory," Thackeray explains. "In so doing, they have daily contact with operators. So when an operator has a safety concern, they can pull maintenance right over and they can figure out the way to address that unsafe condition immediately."

When their natural work team conducts a lean activity such as a kaizen event or a single-minute exchange of dies (SMED) improvement, maintenance personnel routinely participate, Thackeray says.

Lean Tools for Maintenance

A number of common lean tools can be applied to the maintenance function to remove waste in the delivery of maintenance services and improve equipment performance and reliability.

They include:
  • 5-S (sort, straighten, scrub/shine, standardize and spread/sustain)
  • Elimination of the "Seven Deadly Wastes" (overproduction, waiting, transportation, processing, inventory, motion and defects)
  • Standardized workflow
  • Value-stream mapping
  • Just-in-time
  • Kanban (pull system and visual cues)
  • Autonomation (quality at the source)
  • Mistake-proofing
  • Kaizen
Source: "Applying Lean Concepts to the Maintenance and Reliability Function" a presentation by Bruce Hawkins of the Management Resources Group Inc.

"We may have a kaizen to develop a visual factory replenishment signal for a feeding operation. Maintenance will be involved in that for a number of reasons," he explains. "One is to help design the physical attributes of the pull signal, whether that's putting lines on the floor, a containerized replenishment signal, and on lights or something of that nature. But they also help on the upfront design of that to come up with low-maintenance solutions. From a safety perspective, they look at it from a pre-operations standpoint and ask, 'Does this create a trip hazard? Does this create a pinch point? Does this create an unsafe condition or allow for an unsafe act that we can solve before we ever put it in place?'"

Since applying continuous-improvement principles to maintenance, General Cable's North American plants, on average, have achieved a 40% improvement in their OEE rates over the past decade. Still, General Cable, which has had multiple plants named IndustryWeek Best Plants winners over the years (including two plants in 2009), is striving to improve those rates.

"I don't view it as world-class until you get to the 85% range," Thackeray says.

The Power of TPM

Like many IndustryWeek Best Plants winners and finalists, General Cable practices total productive maintenance (TPM), a comprehensive approach to maximizing equipment effectiveness. The objectives of TPM are to eliminate waste, reduce defects, maximize productivity and engage the work force, and it is considered a key enabler of a lean maintenance strategy.

One important component of TPM, as noted by Lafayette Hill, Pa.-based maintenance consultant and author Joel Levitt in his book "Lean Maintenance," is encouraging operators "to take a greater role in the health and productivity of the machines they are tending."

At the Carrier -- Carlyle Compressor Facility in Stone Mountain, Ga., for example, operators conduct daily "PMs" -- inspections based on checklists of performance and safety criteria specific to their machines -- and typically are empowered to clean, inspect and change filters on their machines as well as check gauges to make sure their machines are operating within defined operating parameters, according to Greg Bailey, facilities manager. In some cases, operators also may perform some fluid changes.

While the daily operator PMs are just one level of preventive maintenance conducted on machines (a work-order system generates a schedule of weekly, monthly and annual routine maintenance), Bailey notes that the operator PMs are "our first line of defense" against problems that could lead to unplanned machine downtime.

Plant manager Matt Walker points out that the facility has added visual indices (such as red and green stripes) on gauges to make it easy for operators to determine if equipment is running within its acceptable parameters. If a gauge "starts creeping up or getting closer to the high side," the operator can log it on his or her TPM sheet for the day, and the supervisor would enter a maintenance work order, Walker explains.

"The operator may not have the training and skillset in electrical and hydraulics troubleshooting, but they understand the basic functions of the machine and how it normally runs, and how it has run," Walker says.

"It's perfectly OK to have operators be responsible for the basics of maintenance."
-- Bruce Hawkins, director of field operations, firm Management Resources Group Inc.

The Carrier -- Carlyle facility, which was named one of IndustryWeek's Best Plants in 2009, has achieved some impressive results from its TPM approach and lean strategies. The plant's average machine availability rate last year was 99.5%. Meanwhile, the plant has reduced the number of maintenance hours by about 20% over the past three years, according to Walker.

Bruce Hawkins, director of field operations for the Southbury, Conn.-based professional services firm Management Resources Group Inc., is a big believer in the power of TPM to "help lean out the maintenance processes." He notes that the TPM philosophy emphasizes the importance of engaging "anybody who has anything to to do with the physical assets of the plant" in "managing and caring for" those assets.

Hawkins adds that with proper training, "it's perfectly OK to have operators be responsible for the basics of maintenance."

"We call the basics of maintenance 'TLC': tightening, lubricating and cleaning," Hawkins explains. "And just like I'm responsible for that on my own car, operators should be responsible for that on the machines they operate everyday. They're the ones who, in essence, own the reliability for their equipment. I don't expect the guy down at the garage to own the reliability of my car -- I do that by taking care of the basics."

While a big part of TPM is operator empowerment, an equally important aspect is how it creates a collaborative relationship between two commonly disparate functions -- maintenance and operations -- asserts John Kravontka, president of manufacturing solutions for Manchester, Conn.-based Fuss & O'Neill Manufacturing Solutions LLC. "In so many plants we walk into, you'll see the operators in one corner saying, 'Man if maintenance could fix this equipment better and if they knew what they were doing, it would run a lot better,'" Kravontka says. "And maintenance is in the other corner saying, 'If the operators didn't mess up the equipment and they knew how to operate it, this thing would work better.' It's maintenance versus the operators, and maintenance versus operations. The TPM process helps us pull both of them together to work as a team to improve the equipment performance and reliability."

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