Total Productive Maintenance: An Overview

What it is and how it can improve your OEE

Jonathan Trout, Noria Corporation

Total productive maintenance (TPM) is the process of using machines, equipment, employees and supporting processes to maintain and improve the integrity of production and the quality of systems.

Total Productive Maintenance  

What Is Total Productive Maintenance (TPM)?

According to Aberdeen Research, the average hourly cost of downtime across all businesses is $260,000, and it seems to be rising. This figure is up from the 2014 data of $164,000. This is especially concerning since nearly all industrial and manufacturing production is accomplished using machines, making it largely dependent on those machines operating continuously.

So, how can you help remedy this issue? Total productive maintenance (TPM) is the process of using machines, equipment, employees and supporting processes to maintain and improve the integrity of production and the quality of systems. Put simply, it's the process of getting employees involved in maintaining their own equipment while emphasizing proactive and preventive maintenance techniques. Total productive maintenance strives for perfect production. That is:

  • No breakdowns
  • No stops or running slowly
  • No defects
  • No accidents

Since the goal of total productive maintenance is to improve productivity by reducing downtime, implementing a TPM program can greatly impact your overall equipment effectiveness (OEE) over time. To do this, preventive maintenance should always be at the forefront of everyone's mind. For example, running machines with the mindset of "we'll fix it when it breaks" is not an option with total productive maintenance. A TPM program helps get rid of this mindset and turns it into one of putting machinery at the core focus of an operation and maximizing its availability.

Improving OEE through TPM is often done by forming small, multidisciplinary teams to address core areas such as preventive and autonomous maintenance, training employees who operate machinery, and the security and standardization of work processes. Total productive maintenance focuses on the efficient and effective use of the means of production, meaning all departments should be involved. These small teams work together to increase productivity and decrease downtime through equipment reliability.

 

Benefits of Total Productive Maintenance (TPM)

Going from reactive to predictive maintenance is one of the biggest advantages of implementing a TPM program. Reactive maintenance or "firefighting" is costly, as you're not only footing the bill for machinery repairs but also dealing with the cost of unplanned downtime. Let's take a look at some of the direct and indirect benefits that result from total productive maintenance.

Benefits of Total Productive Maintenance
Direct Benefits Indirect Benefits
Less unplanned downtime resulting in an increase in OEE Increase in employee confidence levels
Reduction in customer complaints Produces a clean, orderly workplace
Reduction in workplace accidents Increase in positive attitudes among employees through a sense of ownership
Reduction in manufacturing costs Pollution control measures are followed
Increase in product quality Cross-departmental shared knowledge and experience
 

The 8 Pillars of Total Productive Maintenance (TPM)

Traditional total productive maintenance was developed by Seiichi Nakajima of Japan. The results of his work on the subject led to the TPM process in the late 1960s and early 1970s. Nippon Denso (now Denso), a company that created parts for Toyota, was one of the first organizations to implement a TPM program. This resulted in an internationally accepted benchmark for how to implement TPM. Incorporating lean manufacturing techniques, TPM is built on eight pillars based on the 5-S system. The 5-S system is an organizational method based around five Japanese words and their meaning:

8 Pillars of Total Productive Maintenance
  • Seiri (organize): eliminating clutter from the workspace
  • Seiton (orderliness): ensure order by following "a place for everything and everything in its place"
  • Seiso (cleanliness): clean the workspace and keep it that way
  • Seiketsu (standardize): standardize all work processes, making them consistent
  • Shitsuke (sustain): constantly reinforcing the first four steps

The eight pillars of total productive maintenance focus on proactive and preventive techniques to help improve equipment reliability. The eight pillars are: autonomous maintenance; focused improvement (kaizen); planned maintenance; quality management; early equipment management; training and education; safety, health and environment; and TPM in administration. Let's break down each pillar below.

  1. Autonomous maintenance: Autonomous maintenance means ensuring your operators are fully trained on routine maintenance like cleaning, lubricating and inspecting, as well as placing that responsibility solely in their hands. This gives machine operators a feeling of ownership of their equipment and increases their knowledge of the particular piece of equipment. It also guarantees the machinery is always clean and lubricated, helps identify issues before they become failures, and frees up maintenance staff for higher-level tasks.

    Implementing autonomous maintenance involves cleaning the machine to a "baseline" standard that the operator must maintain. This includes training the operator on technical skills for conducting a routine inspection based on the machine's manual. Once trained, the operator sets his or her own autonomous inspection schedule. Standardization ensures everyone follows the same procedures and processes.

  2. Focused improvement: Focused improvement is based around the Japanese term "kaizen," meaning "improvement." In manufacturing, kaizen requires improving functions and processes continually. Focused improvement looks at the process as a whole and brainstorms ideas for how to improve it. Getting small teams in the mindset of proactively working together to implement regular, incremental improvements to processes pertaining to equipment operation is key for TPM. Diversifying team members allows for the identification of recurring problems through cross-functional brainstorming. It also combines input from across the company so teams can see how processes affect different departments.

    In addition, focused improvement increases efficiency by reducing product defects and the number of processes while enhancing safety by analyzing the risks of each individual action. Finally, focused improvement ensures improvements are standardized, making them repeatable and sustainable.

  3. Planned maintenance: Planned maintenance involves studying metrics like failure rates and historical downtime and then scheduling maintenance tasks based around these predicted or measured failure rates or downtime periods. In other words, since there is a specific time to perform maintenance on equipment, you can schedule maintenance around the time when equipment is idle or producing at low capacity, rarely interrupting production.

    Additionally, planned maintenance allows for inventory buildup for when scheduled maintenance occurs. Since you'll know when each piece of equipment is scheduled for maintenance activities, having this inventory buildup ensures any decrease in production due to maintenance is mitigated.

    Taking this proactive approach greatly reduces the amount of unplanned downtime by allowing for most maintenance to be planned for times when machinery is not scheduled for production. It also lets you plan inventory more thoroughly by giving you the ability to better control parts that are prone to wear and failure. Other benefits include a gradual decrease in breakdowns leading to uptime and a reduction in capital investments in equipment since it is being used to its maximum potential.

  4. Quality maintenance: All the maintenance planning and strategizing in the world is all for naught if the quality of the maintenance being performed is inadequate. The quality maintenance pillar focuses on working design error detection and prevention into the production process. It does this by using root cause analysis (specifically the "5 Whys") to identify and eliminate recurring sources of defects. By proactively detecting the source of errors or defects, processes become more reliable, producing products with the right specifications the first time.

    Possibly the biggest benefit of quality maintenance is it prevents defected products from moving down the line, which could lead to a lot of rework. With targeted quality maintenance, quality issues are addressed, and permanent countermeasures are put in place, minimizing or completely eliminating defects and downtime related to defected products.

  5. Early equipment management: The TPM pillar of early equipment management takes the practical knowledge and overall understanding of manufacturing equipment acquired through total productive maintenance and uses it to improve the design of new equipment. Designing equipment with the input of people who use it most allows suppliers to improve maintainability and the way in which the machine operates in future designs.

    When discussing the design of equipment, it's important to talk about things like the ease of cleaning and lubrication, accessibility of parts, ergonomically placing controls in a way that is comfortable for the operator, how changeovers occur and safety features. Taking this approach increases efficiency even more because new equipment already meets the desired specifications and has fewer startup issues, therefore reaching planned performance levels quicker.

  6. Training and education: Lack of knowledge about equipment can derail a TPM program. Training and education apply to operators, managers and maintenance personnel. They are intended to ensure everyone is on the same page with the TPM process and to address any knowledge gaps so TPM goals are achievable. This is where operators learn skills to proactively maintain equipment and identify emerging problems. The maintenance team learns how to implement a proactive and preventive maintenance schedule, and managers become well-versed in TPM principles, employee development and coaching.
  7. Safety, health and environment: Maintaining a safe working environment means employees can perform their tasks in a safe place without health risks. It's important to produce an environment that makes production more efficient, but it should not be at the risk of an employee's safety and health. To achieve this, any solutions introduced in the TPM process should always consider safety, health and the environment.

    Aside from the obvious benefits, when employees come to work in a safe environment each day, their attitude tends to be better, since they don't have to worry about this significant aspect. This can increase productivity in a noticeable manner. Considering safety should be especially prevalent during the early equipment management stage of the TPM process.

  8. TPM in administration: A good TPM program is only as good as the sum of its parts. Total productive maintenance should look beyond the plant floor by addressing and eliminating areas of waste in administrative functions. This means supporting production by improving things like order processing, procurement and scheduling. Administrative functions are often the first step in the entire manufacturing process, so it's important they are streamlined and waste-free. For example, if order-processing procedures become more streamlined, then material gets to the plant floor quicker and with fewer errors, eliminating potential downtime while missing parts are tracked down.
 

How to Implement Total Productive Maintenance (TPM)

Now that you have an understanding of the foundation (5-S system) and pillars on which the TPM process is built, let's take a look at how to implement a TPM program. This is generally done in five steps: identifying a pilot area, restoring equipment to prime operating condition, measuring OEE, addressing and reducing major losses, and implementing planned maintenance.

Total Productive Maintenance 5 steps

Step 1: Identify a Pilot Area

Using a pilot area to begin implementation helps gain more acceptance from staff when they see the benefits that come out of the process. When choosing equipment for a pilot area, consider these three questions:

  • What's the easiest to improve? Selecting equipment that is easiest to improve gives you the chance for immediate and positive results; however, it doesn't test the TPM process as strongly as the other two options.
  • Where's the bottleneck? Choosing equipment based on where production is clearly being held up gives you an immediate increase in total output and provides quick payback. The downside is that employing this equipment as a pilot means you're using a critical asset as an example and risk the chance of it being offline longer than you would like.
  • What's the most problematic? Fixing equipment that gives operators the most trouble will be well-received, strengthening support for the TPM program. However, this doesn't give you as much immediate payback as the previous approach, and it may be challenging to obtain a quick result from figuring out an unsolved problem, leading to disinterest.

If this is your first time implementing a TPM program, your best choice is typically the first approach – the easiest equipment to improve. If you have some or extensive experience with total productive maintenance, you may choose to correct the bottleneck. This is because you can build temporary stock or inventory, making sure downtime can be tolerated, which minimizes risk.

Include employees across all aspects of your business (operators, maintenance personnel, managers and administration) in the pilot selection process. It's a good idea to use a visual like a project board where you can post progress for all to see.

Step 2: Restore Equipment to Prime Operating Condition

The concept of restoring equipment to prime operating condition revolves around the 5-S system and autonomous maintenance. First, TPM participants should learn to continuously keep equipment to its original condition using the 5-S system: organize, cleanliness, orderliness, standardize and sustain. This might include:

  • Photographing the area and current state of the equipment and then posting them to your project board.
  • Clearing the area by removing unused tools, debris and anything that can be considered waste.
  • Organizing the tools and components you use regularly (a shadow board with tool outlines is a popular option).
  • Cleaning the equipment and the surrounding area thoroughly.
  • Photographing the improvements of the equipment and surrounding area and then posting to the project board.
  • Creating a standardized 5-S work process to maintain the continuity of this process.
  • Auditing the process with lessening frequency (first daily, then weekly, etc.) to ensure the 5-S process is being followed (update the process to keep it current and relevant).

Once you've established a baseline state of the equipment, you can implement the autonomous maintenance program by training operators on how to clean equipment while inspecting it for wear and abnormalities. Creating an autonomous maintenance program also means developing a standardized way to clean, inspect and lubricate equipment correctly. Items to address during the planning period for the autonomous maintenance program include:

  • Identifying and documenting inspection points, including parts that endure wear.
  • Increasing visibility where possible to help with inspection while the machine is running (replacing opaque guarding with transparent guarding).
  • Identifying and clearly labeling set points with their corresponding settings (most people put labels with settings directly on the equipment).
  • Identifying all lubrication points and scheduling maintenance during changeovers or planned downtime (consider placing difficult-to-access lubrication points that require stopping the machine on the outside of the equipment).
  • Training operators to make them aware of any emerging or potential issues so they can report them to the line supervisor.
  • Creating an autonomous maintenance checklist for all operator-controlled tasks.
  • Auditing the process with lessening frequency to ensure the checklist is being followed.

Step 3: Measure OEE

Step three requires you to track OEE for the target equipment, either manually or using automated software (as long as it includes code tracking for unplanned stoppage time). For details on how to calculate OEE manually, reference Reliable Plant's article on OEE. Regularly measuring OEE gives you a data-driven confirmation on whether your TPM program is working and lets you track progress over time.

Since the biggest losses in regard to equipment are the result of unplanned downtime, it's important to categorize every unplanned stoppage event. This gives you a more accurate look at where a stoppage is occurring. Include an "unknown" or "unallocated" stoppage time category for unknown causes.

It's recommended that you gather data for a minimum of two weeks to get an accurate representation of the unplanned stoppage time and a clear picture of how small stops and slow cycles impact production. Below is a simplified example of a top 5 loss chart. Each loss is categorized and is in descending order from the loss that causes the most downtime to the loss that causes the least.

Top 5 Loss Chart
Loss Rank Loss Category Lost Time (minutes)
1 Equipment Failure: Filler Jam 400
2 Equipment Failure: Bottle Labeler Down 250
3 Setup/Adjustments: Bottle Change 170
4 Setup/Adjustments: Label Change 165
5 Equipment Failure: Bottle Jam 10
Total Lost Time = 995 minutes (16.5 hours)

Step 4: Address/Reduce Major Losses

Once you've got a data-driven snapshot of where your top losses are, it's time to address them. This step uses the previously discussed pillar of focused improvement or kaizen. To do this, put together a cross-functional team of operators, maintenance personnel and supervisors that can dissect the OEE data using root cause analysis and identify the main cause(s) of the losses. Your team's process might look something like this:

  • Select a loss based on OEE and stoppage time data. This should be the biggest source of unplanned stoppage time.
  • Look into the symptoms of the problem(s). Collect detailed information on symptoms like observations, physical evidence and photographic evidence. Using a fishbone diagram to track symptoms and record information while you're at the equipment is strongly recommended.
  • With your team, discuss and identify potential causes of the problem(s), check the possible causes against the evidence you've gathered, and brainstorm the most effective ways to solve the issue.
  • Schedule planned downtime to implement the agreed-upon fixes.
  • Once the fix has been implemented, restart production and observe how effective the fix is over time. If it resolves the issue, make a note to implement the change and move onto the next cause of stoppage time. If not, gather more information and hold another brainstorming session.

Step 5: Implement Planned Maintenance

The last step of the TPM implementation process is the integration of proactive maintenance techniques into your program. This involves working off the third pillar of planned maintenance. Choose which components should receive proactive maintenance by looking at three factors: wear components, components that fail and stress points. Identifying stress points is often done by using infrared thermography and vibration analysis.

Next, use proactive maintenance intervals. These intervals are not set in stone and can be updated as needed. For wear and predicted failure-based components, establish the current wear level and then a baseline replacement interval. Once these have been determined, you can create a proactive replacement schedule of all wear- and failure-prone components. When doing this, use "run time" as opposed to "calendar time." Finally, develop a standardized process for creating work orders based on the planned maintenance schedule.

You can optimize maintenance intervals by designing a feedback system. Things like log sheets for each wear- and failure-prone component where operators can record replacement information and component condition at the time of replacement will be key. Additionally, conduct monthly planned maintenance audits to verify the maintenance schedule is being followed and the component logs are being kept up to date. Review the logs' information to see if adjustments to the maintenance schedule need to be made.

What About The Remaining Four TPM Pillars?

You may have noticed the implementation process negated four of the eight pillars: quality management, early equipment management, safety and TPM in administration. So, when should you introduce these activities? They should be instituted as needed. Let's take a look at some examples.

  • Quality maintenance should be introduced to the TPM process when significant issues about quality are being raised by customers or employees.
  • The best time to use early equipment management is when new equipment is in the design phase or is being installed.
  • Safety, health and environment should always be at the forefront of any process or program design. Use it in tandem with the five-step implementation process.
  • TPM in administration should be addressed before you implement the final version of your planned maintenance schedule. Issues in administration like work order delays, processing problems and part procurement greatly delay the rest of the production process.
 

Sustaining the Improvement Achieved with Total Productive Maintenance (TPM)

Implementing a total productive maintenance program offers relatively short-term success. The trick is sustaining that success over the long term. This starts with the employees. If employees buy into the TPM program, envision the improved future of the company and can see how this improved future benefits them, it can create a powerful sense of cohesiveness. Rewarding achievements is an excellent way to strengthen the established cohesiveness among employees.

Another way to achieve sustainable improvement with your TPM program is by having engaging, active leadership. This shows the importance of the program through not just words but actions. Engaging leadership prevents employees from slipping back into old habits and breathes new energy into the process on a regular basis.

Finally, don't overlook kaizen. Continuous improvement helps your TPM program adapt to changing environments and keeps the program from becoming stale and employees from becoming disinterested.

 

Total Productive Maintenance: A Case Study

In the past, American industries have been reluctant to implement total productive maintenance into their current processes. In fact, a survey done by the Manufacturing Research Center showed that only 27 percent of respondents said TPM was a current business initiative, but only 6 percent said they were fully implementing it. Additionally, only 5 percent of respondents said TPM was their plant's approach to maintenance and reliability.

Despite this lack of interest, plants around the world are reaping significant benefits from making total productive maintenance the focus of their maintenance efforts. A study published in the International Journal of Innovative Science, Engineering & Technology found that, in a small-scale polymer company, the OEE value before TPM implementation was 75 percent. After a TPM program was implemented, OEE improved to 85 percent, and a better quality rate was achieved. The study further revealed how profitability increased by 12 percent, as breakdown and maintenance costs dropped sharply (80 and 20 percent) while labor efficiency increased. Many other tangible and intangible benefits were also uncovered as a result of implementing a TPM program.

One of the most discussed case studies for TPM implementation is that of Latin American brewing company Cervecería Cuauhtémoc Moctezuma, makers of six beer brands including Tecate, Dos Equis and Sol. This article lays out the company's TPM success in detail, showing how total productive maintenance plays out in a real-world scenario.

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