Larger, more sophisticated manufacturing companies have been enjoying the benefits of condition based maintenance practices for many years. Unfortunately, the cost of purchasing analytic equipment, training and implementing these programs have prevented many small and mid sized companies from gaining traction in this cost saving methodology. New technologies on the market today are changing this dynamic creating opportunities for all maintenance departments, large and small, to reap the rewards of a more proactive strategy.
Before exploring some of these new products lets first define some terms that are used by reliability professionals, sometimes with great debate as to their differences. For this discussion, we will assume the following:
Preventative Maintenance (PM) – the practice of taking proactive steps to prevent asset failures and unplanned downtime. These could be time based or condition based in nature but the end goal remains the same.
Predictive Maintenance (PdM) – an element of preventative maintenance that uses historical performance or operating condition data to predict when an asset will reach functional failure.
Condition Based Maintenance (CBM) – the practice of periodic or continuous monitoring of an asset's health through temperature, vibration, sound waves, power usage and other methods to help make decisions on when to perform repairs or maintenance.
Simple time based PM is a common practice that consists of adding lubrication, cleaning, checking tightness, etc. Most companies employ at least some form of this even if it’s not consistently carried out. The problem with time based PM, in addition to getting skipped if there are other “fires” to put out, is that you may be lubricating an item that doesn’t need it wasting time and lubricant. In the case of certain equipment such as an electric motor you may end up hastening its failure rather than preventing it.
This is where condition monitoring comes in. You might say, “We monitor the condition of assets, when the bearing starts squealing we tell production we need to shut the machine down and fix it.” Okay, technically that fits the definition. But production may say that you can’t take it down for two weeks – or more.
Two days later, in the middle of the night, you get that dreaded call. The machine is down; it’s costing $2000 every hour, customer orders are now behind and it’s your fault. Sound familiar? This is where asset heath condition monitoring can provide a different outcome. That squealing bearing was giving clues many weeks or even months prior. Using devices that can pick up these clues gives you more time to plan.
Up until recently the only way to do this type of condition monitoring was to spend $30,000 - $40,000 or more on equipment, $5000+ on training and then prioritize what needs to be monitored. Then hope that cutbacks or the person who received the training leaving for greener pastures doesn’t sidetrack your efforts. Far too many companies have equipment sitting on a shelf somewhere that no one knows how to use or exactly what it does.
There are other ramifications of not doing condition based monitoring that make the investment given in the previous example a bargain. It’s possible that the machine failing could present a health risk. There’s the cost of downtime from production lost and idle employees. Oh, and if that bearing is squealing chances are good there will be expensive damage to it's housing or shaft. But still, convincing management of this can be challenging.
Today there are new options with a smaller upfront investment. An entire industry of outside companies has cropped up that will come in and provide maintenance and reliability services. These companies will consult with you to develop an in-house program or provide a turn key solution where they do the monitoring and simply make you aware of troubling equipment trends. Even still, there will be a cost involved in setting up the program as well as the ongoing monitoring. Getting management to understand that this cost is an investment and not an expense can be difficult especially when cash is tight even though it will improve the company’s financial position in the long term.
There is also a new group of products coming to market now that provide a low-cost point of entry and are very simple to operate. One of these is the i-ALERT2 from ITT. They mount on a pump, motor or other moving piece of equipment and continuously monitor the equipment health. There is a simple interface via Bluetooth to a smartphone or tablet application that allows you to create routes, collect data or simply set alarms that warn you very early that things are moving towards failure. Bearing companies and motor manufacturers are coming out with similar products. In many cases these solutions can be implemented for under $500 per monitored point.
For more critical applications or for those companies that can not or do not want to monitor things themselves, cellular or internet connected devices can provide off site monitoring and alarming capability. There are forward thinking companies developing algorithms that predict when an asset will fail from the collected data. The information gathered can then be combined with data from similar applications worldwide to improve the accuracy of the predictions. This sophisticated form of predictive maintenance will maximize asset operating life while reducing unnecessary repairs.
To remain competitive in a global economy, companies must find new creative ways to maximize productivity and efficiency in operations. Eliminating unplanned downtime and reducing repair costs is a great place to start. Condition based preventative maintenance along with predictive strategies provides the tools to help make this happen.
If you were asked what asset absolutely could not stop running in your facility could you identify it? Right now, you are probably thinking through the equipment you have or maybe you already know. You just performed a basic criticality assessment. One of the most fundamental and important tasks you can do for your company is to identify which assets cannot unexpectedly shut down.
Unplanned downtime is the worst-case scenario for any manufacturing company. Lost production effects everyone in the company from scheduling to billing. Mitigating or eliminating unplanned downtime should be the goal of every maintenance technician. Knowing which assets must stay running based on the impact they have on plant production is the first step towards making your life easier. This critically assessment will help you determine which assets in your facility need to be monitored and what frequency of monitoring is appropriate. You will likely decide that some assets should have no monitoring and are best left to run to failure.
The question asked at the beginning either made your minds gears turn or your thoughts went directly to the asset that must run. How did you make that call? What factors did you use to determine that asset was most important? There are many other factors besides production that play a role in determining the criticality of monitoring assets. Here is a quick summary of some factors that need to be considered.
Are there health and/or safety concerns? Some assets can cause significant health, environmental, and safety issues if they fail. If your assets failure will cause any of these to become an issue then it needs to ascend the list of what is most important. While production loss can be very financially painful to the company an environmental or safety hazard can be much worse. No one wants to have an injured coworker or environmental damage occur during an unexpected asset failure.
Will it cause lost production? One of the most stressful times for the maintenance staff is when a production line goes down. Because these outages can quickly cost thousands of dollars, every minute of lost production is cause for concern and in the maintenance world with the production/plant manager breathing down your neck those minutes seem like hours. In determining criticality of each asset, you need to consider how many people will be idled and how large an impact will it have on production if this asset is unavailable. This should be a heavily weighed factor when deciding where an asset falls on your criticality ranking.
Is a batch of product likely to be ruined? In some plants, an extended outage can ruin thousands of dollars of product. For assets that have this vulnerability the cost of a ruined batch needs to be considered and appropriate redundant systems considered. Where this is too costly or not feasible, spare parts should be stocked and a high criticality ranking for monitoring should be considered.
How vulnerable is the asset? An asset under optimal running conditions will run for quite a long time. Reality tells a different story. Often the conditions the asset operates at are less than optimal which shortens the mean time to failure. Understanding and identifying these assets is important to knowing how critical monitoring will be.
Are spares readily available? It always seems like the most important assets are the hardest to quickly repair. No one wants to go to management and tell them that a critical asset has failed and a needed part replacement is days, weeks, or even months out. This can lead to expensive expediting costs and overtime patch work repairs to get back running. Maintaining adequate spares is important but this is not always feasible especially if the spare is very expensive. If the spare is inexpensive it should be kept on the shelf if possible. If spares are readily available and easy to change out then this asset will have a lower rating but if the spare is cost prohibitive, then the monitoring criticality rating will need to be higher.
These factors all play into the criticality assessment of your plants assets. The more historical operating information you can gather as well as equipment manufacturers recommendations the easier completing this assessment will be. This is the first step in helping decide upon a course of action for condition based monitoring, preventative maintenance and predictive analysis. It’s also the starting point for raising the bar on the reliability of your equipment keeping your plant profitably running letting you sleep better at night.