A
maintenance engineer checks the condition of a motor and pump and enters data
into a PC-based PDA. Source:
SKF.
Outside
firms provide several types of maintenance support including engineering,
technical, assets and more. Source: Advanced Automation.
A savvy maintenance strategy begins with hard questions based in reality. What does it cost when a part fails in your production line? How critical is it to your business? Jim Oszewski, manager of maintenance engineering at SKF’s Asset Management Services, tells a story about a bottling line that came to a screeching halt. For many bottlers, an hour of downtime quickly runs into the thousands of dollars. In this particular line, the cause of the problem had nothing to do with the bottling equipment. Because the switchgear for the system was located near the washing and bottling stations, moisture and sugar built up and caused a power interruption. How critical was the switchgear failure to the operation of the bottling line? This seems like a stupid question, but in many cases Oszewski has seen food processors that have never evaluated the cost associated with the failure of specific parts of the system.
What some people may think of as maintenance strategies, Oszewski prefers to call tools (or tasks) used to build a successful maintenance strategy. These tools include run to failure, preventive maintenance (PM), predictive maintenance (PdM) and reliability centered monitoring (RCM). Choosing the tools to protect against loss is the second step of an effective and savvy maintenance strategy, assuming assessing criticalities, the first step, has already been done. In the absence of an actual maintenance strategy, many producers simply run their equipment to failure. This may work for a while, but could eventually put a processor out of business.
Ted MacDonald, asset performance manager with Invensys Process Systems’ Avantis Division, defines maintenance strategy as a holistic concept consisting of tactical elements (PM, PdM and RCM), which addresses the effect of asset availability and utilization on the needs of the business. PM, PdM and RCM all have their place, but their effectiveness is rooted in the application of best practices.
Taking maintenance seriously
“The best way to maintain equipment is not to use it,” jokes Wonderware’s Claus Abildgren, marketing program manager, production & performance management. “It’s always a tradeoff between asset availability and asset utilization.” For example, a processor may want to slow down a packaging line because it will experience longer up time before maintenance is needed. It may run without a stop for six months at the slower speed, but may fail outright in two months when run at maximum speed.Unfortunately many processors elect the run-to-failure mode for a maintenance strategy because they never considered the criticality of a system component failure. Kevin Hardig, SKF global strategic accounts manager, says some processors actually evaluate the criticality of devices, and know that a major failure could kill their business. Yet, they still choose not to implement any maintenance strategies.
While ignorance may be bliss, some processors have other reasons for neglecting maintenance programs. Bob Vogel, Advanced Automation’s director of support services, says many processors put maintenance on the back burner because of resource restraints. For example, a key person or maintenance engineer in the plant leaves, and then everyone scrambles to put out fires.
Similarly, Hardig adds that plant personnel are there to make a product, not to repair machines. So when a problem occurs, and there is only one maintenance person, it’s not likely that line personnel will want to repair equipment. Another problem, says Hardig, is often a lack of properly trained personnel to do the job. For example: a processor has a sophisticated condition monitoring system, and an engineer writes a work order to repair a motor experiencing vibration problems, but there are no experienced motor technicians who can properly overhaul and lubricate the motor.
Vogel sees many processors that don’t even have a simple computer-based system to track maintenance. And when they do buy a computerized maintenance management system (CMMS), they don’t integrate it properly or train enough people on it. All too often, there is only one person in the company that knows how to use it.
Matt Kettunen, project engineering director at Cadbury Schweppes Americas Beverages, suggests there are several good automated systems available, but it’s not necessary to start out with an automated system. “I’m a very strong proponent of having an organized system. It doesn’t matter if you have a database you can query or a stack of paper. A stack of paper is way better than nothing!”
Sometimes processors have maintenance programs in place, and through acquisitions, wind up with several disconnected maintenance software applications, or none at all in some locations. Such was the case with ACA Co-operative Ltd. in Nova Scotia, which produces poultry and eggs. According to Ryan House, IS manager, ACA now consists of two entities that had separate maintenance software applications with repair parts totaling more than 20,000 part numbers. The maintenance applications were also disconnected from ACA’s other business programs. ACA implemented CSB-System software to pull together the maintenance operations from all the facilities, add maintenance functionality where it didn’t exist, and combine it with all business applications to have one cohesive system. Maintenance operations were added to the egg division, hatchery and barns. Maintenance items are now on the balance sheet, and there has been a 20% reduction in company-wide inventory levels.
According to Vlad Bacalu, product manager at Advanced Technology Services, a food processing plant should create an equipment reliability strategy that identifies the correct maintenance tasks performed on the right equipment at the right time for the right reason. Once the criticality of the equipment has been determined, the reliability analysis will identify applicable and effective maintenance tasks to preserve the function of the equipment.
As stated earlier, a maintenance strategy consists of one or more tools or tasks (run-to-failure, PM, PdM and RCM). It might seem as though run-to-failure isn’t a tool or part of a maintenance strategy because it implies the failure of a part may not be that important. And that is a correct implication. “If the cost to the organization and the speed of repair is less than changing the part before failure,” says Rudy Westervelt, president of Power in Learning, “then it can be run to failure. You may run a small motor or a pump to failure, then wire in a new one when it fails.” But he suggests processors have a better plan for their refrigeration system, especially if replacement parts have long lead times. Otherwise, a processor may want to plan a new business that doesn’t use refrigeration.
PM: A place to start
Beyond run-to-failure, Bacalu says tasks can be time directed (PM activities), condition directed (based on findings from PdM tools) or failure finding activities that can be conducted by maintenance personnel or equipment operators. Therefore, a reliability strategy should include the correct use of both PM and PdM activities. Performing PM alone does not provide the complete benefits of a reliability strategy. Studies show that a large number (43%) of PMs cannot be justified by a cost analysis. The same data shows that about 30% of PMs can be eliminated by using predictive maintenance instead, but this approach alone could lead to excessive maintenance costs by performing too much predictive maintenance on the equipment. Bacalu says a reliability study should optimize PMs and eliminate intrusive tasks by replacing them with condition-based monitoring and predictive maintenance tools.From an OEM point-of-view, Kelly Golden, lease supervisor at FMC FoodTech, suggests food processors choose a PM-based strategy because it is fairly easy to implement, simple to teach and cost effective. Most companies that sell equipment provide guidelines for maintenance managers and technicians, making a maintenance program easier to follow and a good first step for processors with no existing maintenance strategy.
PM often works well in the food and beverage industry where multiple processing lines are coupled with filling and packaging lines. According to MacDonald, these lines generally run on an intermittent basis due to campaign production and cleanout cycles mandated by regulation. The inherent periodic shutdowns provide a natural opportunity for carrying out PM.
Though PM is usually better than nothing at all, there are two issues associated with it. First, the “if it ain’t broke, don’t fix it” axiom may be good advice. Second, equipment that actually needs attention may not get it because maintenance time is spent on equipment that doesn’t need it. As in the example of the repair of the 500 hp motor (which showed no signs of wear) at the beginning of this article, maintenance done by the calendar may not be necessary. In this case, says Hardig, technicians reinstalled the bearings incorrectly resulting in motor failure four weeks later. This shut down the line for some time while the processor scrambled to repair the motor. Brandon Henning, GE Fanuc Automation, food and beverage industry leader, suggests teaching employees “flow to the work.” “Often you will find employees doing PMs when another piece of equipment is down. Make sure that you have a good flow-to-the-work system that both encourages effective preventive programs and shows how to move to the breakdowns as they occur.”
Henning also suggests processors develop a good equipment hierarchy for the plant that allows understanding of the key components for each line as well as sub-components. This hierarchy will help employees understand how each component relies on the others on the line and allows plant management to do cost roll-ups that show how outages and long repairs affect the profitability of the plant at different levels.
PdM applications
According to David Barberree, food industry account manager for Rockwell Automation, in applications where downtime is unacceptable, product quality is at risk and repair and replacement costs are high, a PdM approach should be applied. For example, large grinding applications can cause huge amperage spikes in motors, causing energy issues. When manufacturers change from one batch to another, some products can cause motors to overheat. Food processors must make sure they have the tools to understand the health of their equipment and identify the potential downtime associated with that particular batch recipe. A predictive approach lowers the total cost of ownership, maximizes efficiency and bandwidth, and helps identify the root causes of maintenance and reliability issues. Manufacturers may shy away from this approach, however, since it requires upfront investment, commitment and additional knowledge and skills for each application involved.While PdM has been highly valued in the petroleum refining and power generation industries where, according to MacDonald, failure in complex equipment could lead to catastrophic failure, some food processors are adopting it in applications where unplanned failure cannot be tolerated or afforded. A PdM system relies upon various types of sensing devices (vibration, temperature, IR, etc.), combined with appropriate asset performance management software. This software can monitor critical equipment and, if the software has a rules engine, can analyze the incoming data in various ways, interpret it and offer preliminary actions so the maintenance staff can avert a major failure.
According to Matt Ruth, director of the food and beverage group at Advanced Automation, vibration monitoring and PdM tools are used in about 1% of the food industry. But it’s this 1% that is ahead of the curve. Ruth sees a lot of run-time tracking, but there aren’t many processors taking advantage of condition monitoring techniques such as monitoring the bearings in mixer motors. For some manufacturers who are already using process control systems such as Wonderware, conditioning monitoring tools may be available or already in place, both real time and historical.
RCM strategies
According to MacDonald, RCM has its roots in the airline industry. It involves hypothetical analysis of failure modes and effects on critical equipment and subsequently prescribing the most appropriate maintenance tactics to manage the consequences of the failure. PM, PdM and run-to-failure tactics are often defined from the RCM analysis.According to Robb Dussault, manager Schneider Electric Services, RCM, while representing a perfect balance between reactive, proactive, time-based and condition-based maintenance, is a longer-term ideal to work toward, much like Six Sigma quality standards. A realistic plan should include short- and medium-term phases that consider available technology, current processes and training at every staff level.
RCM may not be practical for every processor. Often, current best manufacturing practices can be used to determine RCM’s applicability. For those still at a run-to-failure mode, RCM may be overkill. Henning suggests the following steps.
“A maintenance program should be viewed as a profit center-not a cost center,” says Hardig. Processors don’t realize the impact on the bottom line until equipment fails. Hardig describes one instance where a processor increased the reliability of existing equipment through proper maintenance strategies and obviated the need to build a new line.
“Maintenance is about costs,” says Patrick Pilz, president/CEO of CSB System-International. “You do maintenance to enhance your ability to execute customer orders. With a maintenance system, you want to get a certain ‘equipment availability’ at the lowest cost possible.” Pilz adds, “If you don’t have these numbers, a good start is putting systems in that get you the numbers you need to make these decisions. The biggest savings from maintenance systems [often] come where you would least expect them.”
For more information:
Kevin Hardig, SKF, 513-941-8254, kevin.g.hardig@skf.com
Ted MacDonald, Invensys/Avantis, 905-516-9560, ted.macdonald@ips.invensys.com
Claus Abildgren, Wonderware, 949-727-3200, claus.abildgren@wonderware.com
Jim Oszewski, SKF, 925-943-7077, jjoszewski@erineng.com
Bob Vogel, Advanced Automation, 610-458-8700, robert.vogel@advancedautomation.com
Vlad Bacalu, Advanced Technology Services, 309-693-5959, vbacalu@advancedtech.com
Rudy Westervelt, Power in Learning, 909-563-8700, rudy@powerinlearning.com
Kelly Golden, FMC FoodTech, 678-797-4253, kelly.golden@fmcti.com
Brandon Henning, GE Fanuc, 434-978-6139, brandon.henning@ge.com
David Barberree, Rockwell Automation, 852-9036-0450, dabarberree@ra.rockwell.com
Matt Ruth, Advanced Automation, 610-458-8700 (ext. 274), mruth@advancedautomation.com
Robb Dussault, Schneider Electric Services, 978-975-9679, obb.dussault@us.schnieder-electric.com
Patrick Pilz, CSB-System Intl., 619-640-0436 (ext. 203), obb.dussault@us.schnieder-electric.com
Sidebar 1: How to create a maintenance strategy
1. Understand the characteristics of your plant operations. This is important because it will affect maintenance resource use, windows of opportunity, preventive maintenance (PM)/predictive maintenance (PdM) schedules and the amount of maintenance required.2. Establish a maintenance plan for each process and packaging line. This should include appropriate preventive maintenance routines as well as elements of non-destructive testing where appropriate.
3. Establish a maintenance schedule for the plant, balancing the production and maintenance needs to use available windows of opportunity first, and then look at the best way to use specifically created maintenance windows.
4. Establish the initial policy for spare parts and the overhaul and/or rebuild of production equipment.
5. Establish best practice processes and procedures for conducting maintenance, including the necessary technology to facilitate these, such as a computerized maintenance management system (CMMS) or an enterprise asset management (EAM) solution.
Source: Invensys Process Systems.
