Machine maintenance isn’t just about preventing breakdowns. It’s also done to improve safety and quality. A well-maintained machine doesn’t suffer micro stoppages that need operator attention, and isn’t a source of variability in the parts being made.
There are many ways to approach machine maintenance. A few manufacturers, wary of spending time and money on the wrong things, choose to run equipment until it fails. Others employ sophisticated approaches to predict failures and perform maintenance only when it’s needed.
The reality is, for most manufacturing companies effective maintenance means having different approaches for individual lines, cells, and machines. Below, we’ve compiled some advice for improving your equipment’s life and reliability with appropriate maintenance strategies.
“Maintenance” is any work done to put a machine in good working order — or to keep it in good working order. It ranges from carrying out inspections like checking the level of lubricating oils and hydraulic fluids, to troubleshooting faults and replacing major components and subassemblies like pumps and motors.
There are two major challenges with performing machine maintenance. One is that it’s expensive. The other is that it’s very hard to know what maintenance must be done.
The expense results from employing maintenance technicians to do the work, and from shutting down equipment. Shutting down machinery for anything other than the simplest visual checks results in downtime — which usually means lost production. However, the alternative is doing maintenance outside normal working hours, which costs even more.
Some maintenance involves routine upkeep like changing oil and replacing filters. Other times it’s done in response to a reported problem. This could be a breakdown, but may just be something that needs constant adjustment or nursing.
The latter of these are often the problems that machine operators accept they have to live with because maintenance technicians are too busy. However, these issues can increase variability in the product being made, which can often lead operators to take shortcuts that affect safety.
Most maintenance departments attempt to anticipate breakdowns, and carry out essential repairs to prevent them. However, as predicting failures is very difficult, what usually happens is that the cost and disruption of maintenance rise while breakdowns continue to occur.
It’s possible to do too much maintenance as well as too little (too much in this context meaning no measurable improvement in uptime or other metrics). More often though, manufacturers suffer from performing the wrong maintenance. In other words, they put significant time and effort into machinery maintenance but still experience breakdowns on key pieces of equipment.
The key to effective machine maintenance is to use a mix of strategies geared to the needs of individual machines. This is typically related to the impact on production of unplanned downtime, although safety is almost always another consideration.
To give a common example, many factories depend on compressed air to operate most of their machinery. If there’s only one air compressor in the factory and it breaks down, the factory could lose an entire shift’s worth of output. Conversely, if one out of five palletizing lines goes down the factory only loses 20% of its capacity. Thus, it’s more important to keep the compressor running than the palletizing lines.
To prevent key equipment from breaking down, a manufacturer will probably devote considerable time and effort to preventive maintenance — maintenance designed to keep it in good working order. Details depend on the type of equipment but may include regular oil and filter changes, as well as monitoring temperatures, pressures, and sometimes vibration.
A well-designed factory maintenance program will take account of both equipment importance and the risk of failure. Using this approach, older equipment with a high failure impact potential will receive more attention than a newer, but less important machine.
Most regular maintenance is performed on a fixed schedule, such as replacing an HVAC filter every six months. While this method is effective for simple, low-cost service work, it carries the risk of replacing items too often or not often enough.
A more sophisticated approach is to schedule maintenance on a usage basis. This is analogous to changing the oil in a car every 3,000 or 6,000 miles. It reduces the risk of doing unnecessary work (provided that the scheduled frequency is based on data), but doesn’t take account of the type of usage the car or machine has seen. For example, urban driving requires more frequent oil changes.
In order to develop a maintenance program structured around the needs and usage of each machine and piece of equipment, you need data on failures and operating hours. Over time, this forms a history for each machine and piece of equipment. By reviewing these records it’s possible to predict when key components might fail and by extension, when they should be replaced to avoid breakdown. This logic is the basis of predictive maintenance.
Manufacturers agree, predictive maintenance is the most cost-effective way of preventing machine downtime, as long as data collection doesn’t become a huge task. This is where machine monitoring comes in.
Breakout: Machine Monitoring Makes Preventative Maintenance Easy
Machine monitoring automates the collection of data about whether a machine is in production or not.
This data is useful for production monitoring— and also for logging actual “runtime” hours to inform maintenance scheduling. That way, maintenance is only performed when the machine has run for a certain amount of hours, preventing over-maintenance.
Preventative maintenance programs use some or all of these six strategies:
Effective maintenance starts by knowing and following the manufacturer’s recommendations for machine upkeep. These generally comprise a long list of points to inspect, plus a number of measurements to be made, followed by adjustment as needed. Component replacement is rarely defined, other than to change oil and filters.
Recommended maintenance is machine-specific but often includes:
It’s easy to overdo or underdo maintenance, which is what happens when you follow fixed schedules or take a reactive approach. Finding the optimal point — where maintenance costs are lowest without sacrificing levels of availability, safety, and performance — requires data.
A machine maintenance strategy takes several factors into account. It’s likely that different strategies will be needed for various machines and pieces of equipment. It’s also almost certain that the strategy will need to change over time in response to business conditions, changes in product mix, and so on.
Important factors to consider when developing a strategy include:
In most factories, responsibility for carrying out maintenance work is divided between a number of different groups or specialties, principally:
Certification provides a way of verifying skills and competencies. In the machine maintenance world, the leading authority is the Society for Maintenance and Reliability Professionals (SMRP). They offer three types of certification: Certified Maintenance and Reliability Professional, (CMRP), Certified Maintenance and Reliability Technician (CMRT), and Certified Asset Management Assessor (CAMA.)
The CMRP credential relates more to managing maintenance activities than to directly performing maintenance work. It’s recognized by ANSI, which adds value, and applicants must take and pass an exam.
As per the SMRP website, “The CMRT exam tests competency and knowledge of specific tasks within four (4) domains: Maintenance Practices, Preventative and Predictive Maintenance, Troubleshooting and Analysis, and Corrective Maintenance.” This is geared towards recognizing the capabilities of multi-skilled people who perform a variety of troubleshooting, maintenance, and repair work.
CAMA certification demonstrates the ability to audit asset management systems. This is similar to being a quality systems auditor and relates more to verifying compliance with procedures than performing actual maintenance work.
Two other types of certification to consider are those provided by Community Colleges and those from the International Maintenance Institute (IMI). Community College certifications are often pursued as part of an apprenticeship with a nearby business. The IMI website says they offer “three levels of certification for the skilled trades or technicians and two levels for maintenance management.” Achieving IMI certification, which has a number of prerequisites, entails passing a written exam. If passed, the certificate is valid for two years.
Machine maintenance is carried out to avoid or reduce other costs. The direct benefits of performing maintenance are that machines suffer fewer breakdowns, they remain safe to use, and the product coming off them is consistent and high quality. The flipside is that if not enough maintenance (or the wrong type of maintenance) is performed, then availability, quality (which show up in OEE measures), and safety will all deteriorate.
Reducing unplanned downtime increases capacity and also supports better schedule adherence. There’s less need to work overtime to make up for delays, so unit labor costs are lower.
Although the human cost is far higher, accidents can be extremely expensive for a business. There’s the immediate disruption, plus time spent on corrective or remedial actions. There’s also the possibility of claims against the company or a safety citation.
Developing and launching an effective machine maintenance strategy does mean incurring some costs. If there isn’t one already in use, you will need to implement a computerized maintenance management system (CMMS) to retain all the relevant machine history data. Identifying maintenance needs takes time and effort, as does defining and documenting the work to be done.
If you want to implement preventive and even predictive maintenance, you need to select the appropriate monitoring technologies. Mostly, this will be in conjunction with advanced tools for identifying work needed, possibly up to artificial intelligence (AI) systems.
Lastly, many businesses find that implementing effective maintenance strategies initially leads to an increase rather than a reduction in work. This is because it takes time for the improvements to show up in the form of fewer breakdowns, better quality, and so on.
Ultimately, businesses will see lower rates of equipment failure and a higher ROI in better maintenance, but it doesn’t happen overnight. It requires advanced monitoring and planning tools, the will to carry out the additional catch-up work needed, and the flexibility to adapt based on the machine data captured.
Should any reader still question the benefits of machine maintenance, here’s a recap:
The priority placed on maintenance and maintenance programs varies by industry. In continuous process industries like oil refining, plastics, and chemicals production, it’s imperative that linked equipment functions safely and reliably all the time. As a result, maintenance management is a core necessity and a major expense.
In industries with more production flexibility it’s often possible to work around inoperable machinery by moving product between lines. This may incur cost penalties, but they’re not as large as in the industries discussed previously. Consequently, machine maintenance tends to take a lower priority.
Every industry and business that uses equipment to manufacture products needs to carry out some level of maintenance to keep production running. These examples illustrate some of the differences and commonalities:
For information on capturing machine usage data and creating smarter maintenance schedules, check out Amper’s maintenance app.
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