Predictive Maintenance Environment in Food Processing Plants Provides Early Warning System

Maintenance is moving from preventive to predictive mode with condition monitoring, maintenance system upgrades and the promise of easier integration.

By Bob Sperber, contributing editor

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Fix Me - Serving Up Condition-based Maintenance

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Plug it in?: The decision to integrate condition monitoring

Want to save $616,500 a year on a couple of sets of bearings? Consider this simple math word problem:

Johnsonville Sausage LLC had nine checkweighers on which the $55 bearings (50 per machine) were wearing out every two weeks [$55 X 50 bearings X 9 machines X 26 replacements per year = $643,500 per year].

The maintenance guy replaced them with $75 bearings that lasted 15 months each [$75 X 50 bearings X 9 machines X 0.8 replacements per year = $27,000 per year].

“And that doesn’t include my team’s labor,” says Tom Ehrenberg, engineering systems analyst at the Johnsonville, Wis., sausage company. “I wouldn’t have noticed the repair and purchasing history without the trending and analysis of a CMMS [computerized maintenance management system],” he says. In his case, it was the MaintiMizer from Ashcom Technologies Inc.

For more than two decades, the maintenance profession has undergone an evolution from fixing equipment when it breaks to preventing failures to predicting when problems will occur. The results are lower risks to products, productivity and people working in the plant.

Working in a predictive maintenance (PdM) environment can provide this kind of early warning. But not everything needs to be predicted; some assets are more cost-effectively maintained by other means. Plants must consider the three alternative approaches to maintenance for any given asset. According to David Berger, partner in Western Management Consultants, Toronto, they are:

  1. Failure-based maintenance (FBM): An asset is run until it fails, at which point it’s repaired or replaced. Depending on the asset, this approach can be hugely economical (e.g., light bulbs), or highly expensive or even life threatening (e.g., large rotating equipment).
  2. Use-based maintenance (UBM): An asset is maintained on a periodic or metered basis such as every three months or 10,000 gallons of use. In many cases, this is a more economical approach than FBM, especially when the consequences or cost of running equipment to failure are higher than the cost of the UBM program.
  3. Condition-based maintenance (CBM): Triggers are established that correlate to impending equipment degradation or failure. When these conditions are identified through periodic inspections or monitoring, defensive actions are taken, such as repair or replacement of a part, to pre-empt the failure just in time.

 

Condition-based monitoring identifies impending equipment degradation or failure so corrective action can be taken before a catastrophic failure.

“There are always three choices for maintaining a piece of equipment,” Berger says. No matter the size or sophistication of reliability engineering and failure modes studies, “The same kinds of fundamental questions apply in any context: What does the asset do? What happens if it fails? What program can we put in place that can cost-effectively ensure its reliability?”

Because of the expense of bringing monitoring technology to bear in data-gathering and historical trend analysis, CBM is typically reserved for the most critical assets in a plant whose failures will most risk a production line to go down, a severe health or safety risk such as an explosion or a repair that will take operations offline and torpedo fulfillment of customer orders.

Condition monitoring technologies are many and varied. Vibration monitoring equipment is commonly used to compare meter readings against manufacturer design specifications to quantify the gradual degradation of shafts or bearings and to decide when it's time to make a repair.

Lubrication analysis goes well beyond viscosity readings for serious PdM-ers, who typically send samples to outside laboratories for detailed measures of particulates, oxidation and flashpoint, which pinpoint causes of performance degradation. Likewise, infrared thermography, ultrasonic and laser monitoring systems are in use across many industries.

“There are a lot of different ways to go about condition monitoring,” says Steve Matthews, business manager for Predictive Maintenance Solutions. The Richmond, Va., company provides laser shaft alignment equipment for rotating machinery from sister company Vibralign, and resells DLI Engineering vibration monitoring systems and services. Customers typically outsource services due to the specialized skills required to analyze the data.

Management systems

Compared to the real-time automation systems that control production machinery and processes, condition monitoring doesn’t require and can’t always benefit from integration from the sensor level into management systems. But at every step, advances in software features and data migration methods are helping to make CBM a more integrated discipline.

In terms of the CMMS/EAM feature set, Berger advises users to look for PdM-friendly features. “At the very least, maintenance professionals should look to include the ability to establish upper and lower control limits that trigger an alarm. Systems should also provide notifications in their workflows to initiate a task when one of these triggers occurs,” he says. Other PdM-friendly features include: 

  • Multiple indicators per asset
  • One indicator can reset all other triggers for a given asset
  • Nesting of triggers with different cycles
  • Combining indicators using Boolean logic to create consolidated/alternate indicators
  • Forecasting future meter readings based on historical readings
  • Validating readings with a user-defined validation formula
  • Basing triggers on calculations of condition-based historical trends. For example, the average, average variance, sum, median, max or min of the last 10 readings can be used to establish control limits
  • User-friendly graphical interface features from color-coded alarm indicators, drill-down features and quick entry of new condition data

Overall, maintenance management systems are becoming more user-friendly in their features as well as in their underlying architectures and their ability to plug and play with condition monitoring solutions. SAP’s Plant Maintenance module and IBM’s Maximo are the 500-pound gorillas in the field.

Invensys offers an integrated platform, from Wonderware plant automation and MES offerings to maintenance systems and condition monitoring hardware and software. At Infor, the latest EAM upgrade adds predictive energy-oriented trending. IFS North America stresses a friendly new user interface as Synactive customizes the SAP front end with its GuiXT suite at Tyson Foods and Foster Farms. And MaintiMizer, a food-targeted CMMS from Ashcom Technologies Inc. expands its functional footprint with CIP routines for sanitation staff and others so that “production, research and QC departments can all operate with the same system,” according to Tim Good, president.

“But the food industry really hasn’t caught on yet,” adds Craig Miller, food accounts manager at Ashcom, Ann Arbor, Mich. “All the audits for food industry has to undergo — AIB, HACCP, GMPs — are taking all the spending. But it’s precisely the kind of data that CMMS systems collect and their auditing functions that can make these certification programs easier.”

“The whole shift today is that there's more integration coming into the picture,” says Wil Chin, director of field systems for ARC Advisory Group. Facing a proliferation of standards and no single best technology for integrating all applications, Chin says “There's always going to be more than once choice. The maintenance guy and the operator only want to view one application that can not only see the automation assets but the production assets — everything from motors to couplings — everything they think is critical should show up on one screen.”

This need is addressed in many kinds of systems, such as the MES systems that display Optimal Equipment Efficiency (OEE) data to both production and maintenance users. 

 

Ideally, maintenance and production should share at least some software, database and middleware tools to provide enterprise-wide asset management.

Maintenance and production share additional software, database and middleware tools to aggregate and apply advanced analytical algorithms to data from distributed process control systems and their Plant Asset Management software add-ons, historical databases and multiple condition monitoring databases. While these remain overkill for most food plants, the technology is creeping toward the mainstream. Additionally, control and software vendors are bringing to market maintenance software products that can support the data flow from control systems to MES systems.

For example, GE Fanuc in April added a “Maintenance Gateway” module to its Proficy automation suite that allows both maintenance and production to share real-time and OEE indicators. The system can reside on the plant floor, in the maintenance department or both. “Whatever pieces of our system you want to integrate, whether it's work order generation or vibration analysis or other condition monitoring measures, we'll provide out-of-the-box integration with EAMs,” says Brandon Henning, GE’s Global Industry Manager for Food & Beverage.

IBM's Maximo system is first with a full interface, to be followed by SAP, Oracle, Datastream and others, the company reports. Henning adds that OPC and other standard integration tools may fill the bill for users in the meantime.

Even at the lowest level of plant-floor automation, smart-transmitting sensors can report self-diagnostic data to warn technicians when they are about to fail. One example is the Ingold line of pH and dissolved oxygen sensors from Mettler-Toledo, Bedford, Mass. They include a smart chip in the sensor tip that diagnoses its own impedance and compares historic calibration trends. “So you can go into a predictive cycle, where the sensor tells you it's time to recalibrate or replace,” says Roger Goavert, engineering, procurement and construction projects manager with Mettler-Toledo Ingold.

From sensor to plant floor to management systems, industry standards are crucial to having these solutions interconnect and communicate with one another.

Standardizing CBM

As information technology and automation standards converge, reliability and maintenance vendors and end users (though none in the food industry yet) are rallying around Open O&M, an umbrella organization itself comprised of standards groups (MIMOSA, ISA, OPC Foundation, WBF and OAGi). The vision of the standard is broad, covering connectivity standards that span everything from sensors and data to front-office business systems.

The effort is in large part aimed at raising the visibility of maintenance leaders to make them “true peer partners with their enterprise systems counterparts in the organization. If they don't, decisions will be made without their input,” says Alan Johnston, president of MIMOSA, the Management Open Systems Alliance and chair of Open O&M.

Why is this important? “Because,” he says, “the corporate guys don't generally come down to the maintenance department and ask those guys for their viewpoint on interoperability standards.”

The core MIMOSA architecture places equal importance on CBM, reliability engineering and maintenance management systems. In the MIMOSA model, “open condition management” starts with sensors, data input and manipulation, alarms and events, diagnostic health assessment and prognostic assessments. Vibration tests, portable data collectors and other tools are used at this “diagnostic health assessment” level. Systems today are generally limited at that level, and human intervention is needed to provide the actual “prognosis assessment” following judgments based on common sense and further studies into methodologies such as root-cause analyses.

“In the old days and at many companies today, the operations and maintenance guys turn weekly planning and scheduling meetings into screaming and shouting matches,” Johnston continues. Production stresses the need to meet production goals, and maintenance argues for preventive and corrective maintenance time. And operations would traditionally win that argument while maintenance is given second-class status.

 

Infrared thermography reveals the motor in the background is running much hotter than the one in the foreground, which is operating under similar load conditions. The reading indicates a bad bearing or some other problem that will soon cause motor failure.

 

Today, he says, more companies are using condition monitoring and additional data to conduct orderly, fully informed meetings where maintenance is a full participant in the discussion. With empirical data, the maintenance representative at the table can say to production, “Look, we’re both trying to achieve operational optimization. If you don’t let me do X, this week’s metrics may make production look good, but next week you may pay for it in quality, yield or safety.” Today’s data-driven and increasingly integrated systems “allow the maintenance guy to be an integral business partner to the operations guy.

“That's the important over-arching theme for the maintenance professional,” says Johnston. “It's no longer about carrying a greasy rag and a wrench. It’s about being a full peer partner in determining what needs to be done for the operation.”

The actual standards are generally from the engineering, automation and especially the information technology worlds. (For example: ODBC, SQL, OPC UA; industrial Ethernet; various sensor, field and device buses). The importance of integration at the top, enterprise level is critical, says Johnston, who has put on many frequent flyer miles promoting the importance of open, integrated maintenance from an enterprise risk management perspective.

Note to Management
“A cultural shift has been going on for the past 20 years in American industry,” says Steve Matthews, business manager for Predictive Maintenance Solutions. “Going forward, the most competitive companies will not be looking at their maintenance departments as cost centers but as profit centers. The real value of maintenance isn’t fixing things when they’re broken. The real value of a maintenance department is to deliver plant uptime.”

SAP, the enterprise vendor with an equally dominant maintenance module, is promoting a survey conducted by Reliabilityweb.com in which only 20 percent of respondents characterized their CMMS/EAM implementation as successful and 57 percent said that theirs failed to generate the anticipated return on investment. That doesn’t sound like cause for celebration. But things could be changing as technology standards like Open O&M (see above article) take root.

In his own pitch to industry, Matthews’ favorite survey is more optimistic for those in a preventive, condition-based maintenance mindset. He cites an Electric Power Research Institute study in which maintenance costs are figured in dollars per horsepower. Reactive or failure-based maintenance was $17, preventive was $13, which is or 24 percent lower, and predictive was $9, which is 47 percent lower than reactive/running to fail.

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