Broken equipment is a cement producer’s worst enemy, causing lost time, productivity and money. While many of these problems can be avoided through an effective predictive maintenance (PdM) program, operators are often hesitant to implement one due to the up-front and ongoing investment required.
According to Ken Rone, vice president of manufacturing services at Ash Grove Cement, a PdM investment is well worth the costs, paying for itself every time equipment failure and downtime is avoided.
Building the foundation
Based in Overland Park, Kan., Ash Grove Cement has nearly 9 million tons of cement capacity and is considered a leader in the U.S. cement industry. The company was founded more than 125 years ago.
Ash Grove first started its corporate Maintenance Excellence Process (MEP) in 2000, establishing standardized PdM equipment and procedures at each of its 10 U.S. plants. What varied was the staffing and consistency of data reporting. Some locations relied on onsite technical personnel while others used third-party consultants for various levels of vibration analysis, infrared thermography and oil analysis.
“We had a high-level, sophisticated program, but we identified vibration analysis as a weak link where we lacked consistency,” said Rone. “We wanted to bring in an independent third party with expertise in this area and began evaluating potential partners in August 2008. We were ready to go with Timken in early 2009.”
Timken is a technical solutions provider focused on improving uptime in industrial equipment. By applying its extensive knowledge of metallurgy, tribology, engineering and data analysis, Timken engineers help to maximize reliability and energy efficiency in machines critical to plant operation.
“We’re at our best when we can bring all our knowledge together to solve a problem,” said Rick Brooks, project manager for Timken’s services group. “When we combine optimal bearing, sealing and lubrication technology with things like proper maintenance, condition monitoring and diagnostic analysis, we really start seeing better results in how our customers’ equipment performs.”
The Ohio-based company also offers in-depth training and consulting services, working with customers to develop a program that suits their needs.
“Timken was the right choice for us because of their consulting experience,” said Rone. “Their evaluation devices also use the same technology platform as our existing PdM equipment, so we were already compatible.”
Establishing a new baseline
One challenge Ash Grove had was consistently collecting baseline readings for vibration analysis levels.
“It’s critical to establish baselines for trending purposes,” said Tod Cotter, project manager for Timken’s services group. “Once the baselines are in place, you have something to compare future readings to – if the amplitude of the readings trend upward, that’s when a problem might be occurring.”
Knowing this, Ash Grove asked Timken’s reliability experts to establish baseline vibration analysis readings and provide consistent, verifiable data for Criticality 1 and Criticality 2 equipment at each plant.
Cotter collected the data and performed analysis on all machines of 1,000 horsepower or more. He then made recommendations for changes in maintenance scheduling and procedures.
“Based on our findings, we provided an audit of what was good and bad at each location,” said Cotter. “Each plant had different equipment and operating parameters, but the process helped us identify existing best practices that could be shared among all the facilities.”
For example, the Ash Grove plants in Leamington, Utah, and Seattle stood out as having solid vibration analysis programs managed by a combination of in-house technicians and outside contractors. Their effective processes were highlighted in Timken’s recommendations and later incorporated into operations at other sites.
Expanding the collaboration
Impressed with Timken’s technical expertise and suggestions, Rone asked the company if it would be willing to help manage predictive maintenance activities at four Ash Grove plants having issues with their existing programs.
“Our approach is to establish a collaboration, not just come in and dictate what a company should do,” said Brooks. “We’re glad to work with Ash Grove’s people – both internal and external – to come up with a custom plan that helps them keep their critical assets running.”
The plan is working. In the first 10 months alone, Timken and Ash Grove discovered 10 instances in which equipment critical to plant operations was starting to fail. These discoveries enabled maintenance personnel to make repairs and replace damaged components before a problem could cause unscheduled downtime.
Avoiding breakdowns in major equipment such as kilns, crushers and fans has the potential to save Ash Grove millions of dollars. One “save” on a raw mill motor at the Leamington plant helped the company avoid approximately $350,000 in downtime costs.
In another case, Timken helped Ash Grove’s plant in Foreman, Ark., avoid an estimated 12 hours of downtime by analyzing data that indicated a fault in a ball mill’s fan gearbox. Removal of the gearbox bearing, which showed severe pitting damage, confirmed a problem. Ash Grove’s maintenance personnel replaced the gearbox before it led to a total system shutdown.
Ash Grove also has made the switch to Timken’s machine evaluator for data collection. The machine evaluator is a handheld instrument that combines sophisticated vibration analysis with shock-pulse monitoring to detect bearing damage and inadequate lubrication, as well as many other problems with mechanical and electrical equipment.
“Shock-pulse works particularly well for monitoring conditions in slow-speed cement equipment,” said Cotter. “The machine evaluator has advanced diagnosis capabilities for detecting machine faults such as imbalance, misalignment and structural weaknesses.”
Ash Grove maintenance personnel and onsite technicians also are receiving training on how to use the machine evaluator and integrate it into a comprehensive PdM program. Additional training related to maintenance and reliability is on the horizon.
Rone said training was a differentiating factor that helped Ash Grove select Timken, and Timken’s willingness to share its technical knowledge has translated into real business value. He also believes that the most successful PdM programs are consistent and ongoing. For example, part of Ash Grove’s MEP strategy is to reconfirm its vibration analysis baselines annually, with the help of Timken.
“Timken has definitely helped us strengthen our PdM practices,” he said. “With their onsite support and accurate data reporting, our own people have more confidence in their decision making. Right from the start, Timken demonstrated a level of technical know-how that is helping us achieve best-in-class results.”
For more information on this and other topics, visit the Timken Web site at www.timken.com.