The concept of lean applies to many aspects of manufacturing, operations, maintenance, and any process in general. As you might guess, being lean aims to trim away the unnecessary portions of your usual activities. The result of this philosophy is a more cost-effective program without sacrificing quality.
What Is Lean Maintenance?
A lean maintenance approach finds its origins in Total Productive Maintenance (TPM), a strategy that maximizes effectiveness through organizational involvement. Essentially, each worker from all levels of the organization supports maintenance and reliability initiatives. The ideas behind TPM are fundamental to a lean approach, including the 5S principle, autonomous maintenance, and continuous improvement. Lean maintenance puts these philosophies into practice to minimize costs while increasing the reliability of equipment and systems.
To understand the meaning of "lean maintenance," we must first look into the definition of lean. In simple terms, being lean means eliminating waste. This concept is frequently used in manufacturing applications. You might have heard of the term "lean manufacturing," which provides a framework to guide manufacturing and service operations. In lean manufacturing, the types of waste to look out for include unplanned downtime, overproduction, waiting time, transportation inefficiencies, and inventory surplus. Lean maintenance is similar to lean manufacturing in the sense that both approaches aim to eliminate waste. However, waste can take different forms when speaking from a maintenance standpoint.
Maintenance-related wastes have a lot to do with nonessential activities. For instance, without the right schedules and criteria to execute tasks, teams are at risk of performing unnecessary maintenance. The precision of identifying the need to perform maintenance before a breakdown significantly reduces nonessential work. Another example of reducing waste is in eliminating inefficient maintenance habits. You want your parts to be available in time for a planned shutdown. This way, you can keep your repair time to a minimum while accomplishing all essential tasks. By efficient scheduling, maintenance teams can maximize any downtime allotted to planned work. This step also reduces the need for costly, not to mention risky, hasty maintenance work.
How to Evaluate the Efficacy of a Lean Maintenance Program
With all the promises of lower costs and maximized reliability, wanting to go lean shouldn't come as a surprise. But how exactly do you know that you've achieved what you expected? Moreover, how do you know whether you've reached your maximum potential or you've got a long way ahead? To manage your objectives and see how you're tracking, you need to put metrics and measures in place. After all, a crucial step to improving your performance is gathering the data to know where you are.
What Metrics Do I Choose to Evaluate the Impact of a Lean Maintenance Program?
Choosing the right metrics can help you get a snapshot of your performance. By having the right ones in place, you can get a sense of your achievements and lowlights for a given period. You can then track how changes in your strategy affect these values as you fine-tune your program. Here are seven areas you can quantify to evaluate the impact of a lean maintenance program:
Hours of unscheduled downtime
Also known as equipment downtime, this metric tells you the amount of lost productivity in a month. While some scheduled downtime is necessary, such as in shutdowns, this metric typically concerns unexpected stoppages.
Cost of unscheduled downtime
Similar to the first metric, the cost of unscheduled downtime relates to the loss of productivity. Expressing this metric in dollars provides more context about its impact on production value losses.
Labor costs of planning and scheduling
Planning and scheduling activities are always going to be part of the maintenance process. Being lean adds value by minimizing these activities and doing things right with precise timing. Not only are you maximizing the time spent on maintenance, but you’re also eliminating the need for any rework.
Labor costs of testing
Similar to planning and scheduling, testing routines are essential to some maintenance procedures. By taking a lean approach, you aim to plan for an efficient order of testing procedures to eliminate waste.
Labor costs of scheduled maintenance
You want to have metrics that compare how you are tracking with what you were planning to do. Monitoring costs allocated to scheduled maintenance gives you an idea of your planned expenses.
Labor costs of unscheduled repairs
As opposed to scheduled maintenance, you generally want to keep your unscheduled work at a minimum. Unexpected repairs mean additional downtime and lower productivity. Lowering these costs is a good sign that your lean maintenance approach is paying off.
Cost of materials for testing, maintenance, and repairs
Now that we've covered the labor costs, we also want to know our material costs. Part of this metric has to do with the way you manage inventory. You want to balance having just the right amount of capital tied into stocked spares while ensuring that you can perform your tasks on schedule.
What Should I Measure in a Lean Maintenance Program?
The previous section gives examples of metrics that can help assess the effects of a lean maintenance program. Those previously discussed evaluation metrics closely relate to the measures you want to keep tracking while running the course of your strategy. Think of these areas as longer-term indicators of your performance.
Compare scheduled versus unscheduled repairs
One of the driving ideas behind a lean approach is minimizing any non-planned work. Throughout your program, there are several ways to quantify this amount. You can take the percentage of work orders for scheduled maintenance and compare that with the total number of work orders. Increasing this percentage puts you in control of your schedule. You can manage the best time to put your equipment out of service for repair. You can even maximize that time and plan several tasks if it makes sense to do so.
Another way to compare the number of scheduled repairs out of the entire list of activities is by looking at your labor time. As with work orders, you want to allocate most of your total work time to scheduled repairs. Note that you might still need to leave room in anticipation of any unscheduled maintenance. A ballpark target of around 80% of labor time assigned to scheduled work is practical.
Track your training
A lean maintenance philosophy promotes a culture that engages the different teams to work efficiently. Tracking training hours might not be the first thing that pops into your mind when talking lean. However, as this measure goes up, so does your maintenance team's ability to focus on more complex tasks.
You can track training progress by quantifying the amount of time the maintenance team spends training operators in testing and preventive maintenance. As experience develops, workers can participate in doing routine condition testing and maintenance. A more hands-on team then compounds your ability to increase reliability while promoting a culture of continuous improvement.
It's easy to misunderstand downtime and strive to eliminate it. But in practical scenarios, it is specifically unplanned downtime that you want to avoid. The distinction between scheduled and unscheduled downtime should reflect in the way you set up your measures. You want to focus on the purposefulness of your equipment's idle time and not merely the amount.
One way to reflect whether or not downtime adds value is by measuring how much of it is due to unscheduled repairs. With higher percentages of planned equipment downtime, then you may be trending in the right direction. Further, you can characterize your measure by factoring in the actual costs incurred by lost production during downtime. Calculate the lost value from periods of inactivity and quantify the percentage coming from scheduled downtime. Similarly, you want the bulk of the costs from lost production to come from planned work instead of unscheduled repairs. That way, you can look at any downtime as a value-adding investment rather than a waste.
Having the right parts at the right time is vital to execute proactive maintenance tasks according to plan. By performing proper analysis, you can drill down into inventory-related issues and be a step closer to a solution.
A good starting point is identifying how much of your downtime is due to a lack of spare parts. Moreover, what is the impact on production if a part is not available on hand? Think of the major components that comprise a piece of equipment that is critical to your operations. If, for example, one of those components suddenly fails, how much is the hourly cost of production losses? What is the part's lead time when coming from the vendor? What is the total stockout cost considering all these variables? Knowing these measures gives you an idea of how inventory management can cut your wastes.
Following the previous scenario, it also helps to track the cost of storing replacement parts on hand. These costs include labor costs of warehouse personnel, preservation costs, and warehouse space requirements. After summing these up, you now have both sides of the equation: the impact of missing a part and the price to stock it. You can then make an informed decision whether or not you need to procure and hold a spare.
How Does a Lean Maintenance Program Reduce Costs?
By now, you can see how a lean mindset reduces waste and finds opportunities to take the most value from a situation. To appreciate how such programs reduce costs, consider the benefits in the following focus areas.
Extend the Life of Assets
Remember that a lean maintenance program is foremost a maintenance approach. It doesn't only aim to reduce costs, but more importantly, increase the availability and reliability of your equipment.
Maximize Manpower Effort
A lean maintenance program recognizes the value of work and labor. The time and effort exerted by maintenance teams focus on value-adding tasks and activities. You can expect to reduce labor costs by targeting the energy of your workforce on jobs that matter.
Optimizing Spares and Maintenance Materials
Where possible, a lean approach aims to bring in resources according to a just-in-time system. A reliable schedule of activities allows teams to prepare for a job ahead of time, and bring in resources just in time. With this system, teams can effectively allocate resources to stock highly critical materials.
Efficient Planning and Scheduling
A lot of the cost reduction from a lean system is rooted in planning and scheduling. In a lean approach, maintenance teams can perform activities with control and focus if efficiently planned.
What If My Lean Maintenance Program Isn't Keeping Costs to a Minimum?
The first thing to keep in mind is that any analysis you do is only as good as your data's quality. Address any inconsistencies that you notice in your data before they become a headache in the future. If you have a CMMS or EAM available, make sure to align its functions with your measures. These tools are already recording a lot of your maintenance activity. Having that information in a form that is ready for analysis can save you heaps of manual work.
With full confidence in your data, you can then look at the metrics that evaluate your execution. If you don't think costs are where they should be, then you can start seeing the red flags from your measures. See which areas are contributing the most waste. In the process, identify opportunities to make your scheduling more efficient. Remember that it's not all about eliminating downtime but making the most of it. Trending towards increasing scheduled tasks and identifying the right maintenance jobs are examples of areas that can pay back in sums.
It may take some time to see significant changes to your bottom line when moving to an entirely new system. What you need to build confidence is the right data and an objective approach to analysis.
5 Lean Tools Used by Manufacturers
Lean maintenance makes use of several tools, processes, and strategies. Some of these are fundamental to lean maintenance, whereas others play more of a supporting role. The most common tools used include the following.
1. 5S Process
Central to lean maintenance and TPM is the 5S process. This process is intended for regular personnel, and it represents steps the average worker can follow in order to support maintenance processes.
5S stands for:
- Sort – Determine which materials to keep on hand and which to discard.
- Straighten – Organize everything to minimize wasted time.
- Shine – Keep equipment, tools, and work areas clean.
- Standardize – Plan when and how the first three S’s will be performed.
- Sustain – Perform audits, support new practices, and sustain the previous 4 S’s long-term.
In lean maintenance, mistake-proofing refers to making plans and implementing procedures to keep mistakes to a minimum. Mistake-proofing might include:
- Making sure preventive maintenance procedures are well defined
- Creating detailed job plans
- Color-coding lubricants and cleaning supplies
- Labeling all equipment
- Creating complete change management processes
The better detailed and user-friendly your plans, procedures, and processes are, the less likely you’ll waste resources due to human error.
3. Kaizen Events
Kaizen events are short-term projects put on by management in order to help a team improve in some way, such as in implementing 5S principles. Typically, these events don’t last longer than a week, and they’re led by a facilitator.
The end goal of a kaizen event is to support continuous improvement. While each event may be treated like a one-off, they should be conducted regularly in different areas of your company. That way, your team members get multiple opportunities to practice 5S principles and other aspects of lean maintenance with the benefit of ongoing feedback.
4. Modern CMMS
Lean maintenance relies on self-directed teams performing tasks automatically, and that requires routine tasks to be scheduled as efficiently as possible. A CMMS can assist with lean maintenance by streamlining maintenance planning and scheduling processes, work order management, and other components.
5. Maintenance Analysis
Continuous analysis of your maintenance processes is key to making sure they are as lean as possible. Areas of your maintenance analysis might include:
- Assessing preventive maintenance tasks to make sure they’re actually effective
- Performing root cause analysis (RCA) to track down the source of equipment failures
- Implementing PdM and condition monitoring on key assets
- Examining workflows and schedule compliance when performing PM tasks
Setting Up a Lean Maintenance Workflow
The process of implementing lean maintenance doesn’t happen all at once. It takes time, and you need a number of elements in play to make it work. The following steps will help you get your lean maintenance process set up.
1. Form a Maintenance Team
You’ll want to start by forming a maintenance team. You’ll need team members who have experience working on the specific assets you’ll be managing since they’ll have a strong sense of what has gone wrong with each. The team might include maintenance technicians, but it could just as easily be composed of machine operators.
2. Choose a Leader
The next step is to choose someone to lead on planning and scheduling maintenance tasks. This person should have a general knowledge of how each machine should be managed, but they also need strong leadership and organizational skills as well.
3. Pick Systems to Manage
Again, lean maintenance doesn’t happen all at once, and it’s often best to start with just one system. Choose one that needs the most help—probably the one that contributes most to maintenance costs or production downtime—and start there. As you learn from implementing lean maintenance practices with that system, you’ll be able to expand to other systems more easily.
Ideally, you’d eventually extend to all systems in your facility, taking maintenance costs down throughout your organization.
4. Schedule Lean Maintenance
Once you have a team, a leader, and a system in place, start determining what tasks need to be done and schedule the best time to complete each.
Within a preventive maintenance strategy, those tasks will be scheduled on a recurring time-centered basis. If you have condition-monitoring instrumentation in place in the system, maintenance scheduling might be based more on when PdM alerts are triggered by your CMMS.
5. Work in Cycles
Lean maintenance involves recurring tasks, and that means your team could face spikes in workloads at regular intervals if you’re not careful. To keep workloads at consistently manageable levels, work in cycles, with your team cycling through different systems to make sure they get to all of them.
This is especially important if you have a lot of machinery or numerous systems to maintain.
Since lean maintenance is proactive, it needs to be repeated regularly in order to make sure each piece of equipment stays in top working condition.
As you repeat each cycle of your lean maintenance procedures, conduct audits to make sure it’s working as efficiently as possible. If you see areas where time or resources are being wasted, make changes to help your team operate more efficiently.
Lean maintenance is more than just cutting costs and eliminating redundant processes. A lean approach aims to maximize value from parts and services to achieve high reliability. With the right focus in place, teams can increase efficiencies and improve their overall performance.