Five steps to applying predictive maintenance

The following steps are predicated on the assumption that all assets in a facility have been identified within a functioning PM program that uses a computerized maintenance management system (CMMS).

10/05/2015


Ensuring the right work is performed at the right time to minimize downtime on production assets is crucial to productivity, but avoiding costly unplanned maintenance is paramount as well. It can be expensive to remove a piece of equipment from production to perform routine preventive maintenance, only to find a function dictated by the Preventive Maintenance (PM) task was not necessary. Predictive Maintenance (PdM) is based on the operating conditions of the asset and the set parameters of its function, rather than time- or calendar-based PMs.

The following steps are predicated on the assumption that all assets in a facility have been identified within a functioning PM program that uses a computerized maintenance management system (CMMS), which includes all planned and unplanned maintenance activities, labor and material costs accurately.

1. Follow the dollars

First, you need to determine where financial and human resources are expended and itemize the assets that are vital to your process. Concentrate first on assets lacking a spare. Aircraft manufacturing is one of the few industries where multiple redundancies are engineered into a product. Chances are, you have a few backups such as supplementary pumps for critical processes. But no one can afford an idle production line just in case it is needed if something breaks down on the primary line.

Using data extracted from the CMMS, identify the high-cost and/or frequent incidents that are consuming the maintenance budget and generating lost production. Examine 2to 3yrof data to ensure all potential issues are addressed. Include the cost of lost product, whether it's pieces, cases, gallons, or tons. Many times these costs are neglected in the calculations, and an important piece of the cost picture is lost. Occasionally, the cost of lost product exceeds that of the repair itself. Just because an incident has a low occurrence rate doesn't mean it should be discounted from a PdM program.

2. Perform analysis

Once you have identified the bad actors by cost/frequency, conduct an analysis to examine the mean time between failure/rate (MTBF/R), and identify whether the mean time is increasing or decreasing. Perhaps you've already undertaken some remedial actions and improved the MTBF/R on a particular unit. However, don't dismiss these incidents even if the number of incidents is decreasing. The time and costs consumed can still be significant and warrant investigation

3. Determine where to use PdM

Some assets are, and will generally be expendable and can be run to failure. A ¼-hp motor on a conveyor segment comes to mind. These motors are likely in stock or can be obtained quickly and easily. However, a 200-hp dc motor on a reversing rougher in a steel mill would be a prime candidate for PdM, as well as its gearbox.

The intent is to identify the assets that would cause a catastrophic impact should they unexpectedly fail. While some assets will immediately come to mind, others may come as a surprise as to their difficulty to detect an impending failure.

To better understand where PdM should be deployed, a failure mode effects analysis (FMEA) exercise should be conducted, with the equipment ranked by their susceptibility of failure based on severity, occurrence, and detection criteria. This will generate the risk priority number on which to prioritize the assets. This requires accurate data from a CMMS to trace past breakdowns.

4. Define the technologies to be used

Not all machines need be included in PdM strategies. However, rotating equipment, gearboxes, and electrical distribution components are prime targets for PdM. Vibration monitoring, oil/wear particle analysis, and thermography are the most prevalent PdM strategies deployed, regardless of the industry. Bearing temperature analysis is also a common tool. The failure that the site is attempting to detect drives the technology employed.

Obviously, there is an initial investment to acquire the needed technology and tools to implement PdM. Prudent research and common sense need to be applied. For example, only one infrared thermography camera needs to be purchased, as it can be used sitewide. The same would be true for vibration monitoring, since a portable unit can be used throughout the facility. Generally, oil analysis is conducted offsite by a firm specializing in tribology, sometimes by the actual oil vendor.

Another factor to remember is training staff in using data collection tools and data analysis. Acquisition of data is meaningless unless there is trained staff to analyze and interpret the results, and actions are taken to correct the potential failures identified. If a site is not going to train staff or use the information obtained, it is better off outsourcing the PdM function.

5. Deploy tools

After the tools have been purchased and the staff trained in their use, you can acquire the initial baseline data and capture the results in the tracking program to plot it against performance standards developed by the site or manufacturer. These results should be continually plotted on an asset deterioration curve. Many software packages are available that will perform this function. Bear in mind, the validity of a deterioration model is based on the accuracy and reliability of the data employed.

When the impending failure has been detected, planning should begin to address the problem at the appropriate time, based on production, business conditions, and the amount of deterioration revealed. A technological strategy for today's high-tech equipment is a sound approach to maintaining assets with minimal production loss. A PdM program can reduce costs and downtime to undertake inspections, as it uses noninvasive tools and procedures without interrupting production. Assets that are properly monitored and maintained via PdM rarely fail and generate unplanned downtime. PdM has the potential to generate savings of about 30% in maintenance expenditures. Too little or too much maintenance is avoided, freeing staff to pursue other activities such as reducing the backlog or performing capital projects.

What's not to like about that?

Mike Johnston, CMRP, is a senior consultant for T.A. Cook.



Top Plant
The Top Plant program honors outstanding manufacturing facilities in North America.
Product of the Year
The Product of the Year program recognizes products newly released in the manufacturing industries.
System Integrator of the Year
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
June 2018
2018 Lubrication Guide, Motor and maintenance management, Control system migration
May 2018
Electrical standards, robots and Lean manufacturing, and how an aluminum packaging plant is helping community growth.
April 2018
2017 Product of the Year winners, retrofitting a press, IMTS and Hannover Messe preview, natural refrigerants, testing steam traps
June 2018
Machine learning, produced water benefits, programming cavity pumps
April 2018
ROVs, rigs, and the real time; wellsite valve manifolds; AI on a chip; analytics use for pipelines
February 2018
Focus on power systems, process safety, electrical and power systems, edge computing in the oil & gas industry
Spring 2018
Burners for heat-treating furnaces, CHP, dryers, gas humidification, and more
April 2018
Implementing a DCS, stepper motors, intelligent motion control, remote monitoring of irrigation systems
February 2018
Setting internal automation standards

Annual Salary Survey

After two years of economic concerns, manufacturing leaders once again have homed in on the single biggest issue facing their operations:

It's the workers—or more specifically, the lack of workers.

The 2017 Plant Engineering Salary Survey looks at not just what plant managers make, but what they think. As they look across their plants today, plant managers say they don’t have the operational depth to take on the new technologies and new challenges of global manufacturing.

Read more: 2017 Salary Survey

The Maintenance and Reliability Coach's blog
Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
One Voice for Manufacturing
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Maintenance and Reliability Professionals Blog
The Society for Maintenance and Reliability Professionals an organization devoted...
Machine Safety
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
Research Analyst Blog
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Marshall on Maintenance
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
Lachance on CMMS
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
Electrical Safety Update
This digital report explains how plant engineers need to take greater care when it comes to electrical safety incidents on the plant floor.
Maintenance & Safety
The maintenance journey has been a long, slow trek for most manufacturers and has gone from preventive maintenance to predictive maintenance.
IIoT: Machines, Equipment, & Asset Management
Articles in this digital report highlight technologies that enable Industrial Internet of Things, IIoT-related products and strategies.
Randy Steele
Maintenance Manager; California Oils Corp.
Matthew J. Woo, PE, RCDD, LEED AP BD+C
Associate, Electrical Engineering; Wood Harbinger
Randy Oliver
Control Systems Engineer; Robert Bosch Corp.
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me