Total Productive Maintenance in Lean Manufacturing

Total Productive Maintenance (TPM) forms a crucial stability component that lays the foundation of the House of Lean Production. It works hand in hand with 5S, which we discussed in the previous chapter.

TPM, or Total Productive Maintenance, takes a holistic approach to equipment maintenance. Its primary objective is to achieve flawless production by eliminating breakdowns, minimizing downtime, reducing product defects, and preventing accidents. 

In practice, TPM relies on visual management to facilitate training and promotion within the workplace.

Now, let’s explore TPM in greater detail and understand how it contributes to creating stability in lean manufacturing.

Total productive management (TPM)

TPM is a maintenance approach that focuses on being proactive and preventive to ensure equipment works efficiently. When companies implement TPM, everyone in the factory is responsible for maintaining the equipment, which gets workers more involved. TPM helps increase productivity by keeping equipment running, making processes faster, and eliminating defects when used in the right environment.

The image above shows how TPM assigns essential maintenance work to production team members, such as inspection, cleaning, lubrication, and tightening. This allocation allows maintenance team members to focus on predictive maintenance, equipment upgrades, repairs, training, and other high-value activities. 

The goal of TPM is to achieve zero breakdowns. To achieve this, we take the following steps to maintain production equipment:

• Stage 1: breakdown maintenance (firefighting)
• Stage 2: Preventive maintenance (proactive planning and troubleshooting)
• Stage 3: 

TPM = (Preventive maintenance + Predictive maintenance) – total involvement

Eight pillars of TPM

TPM implementation relies on eight supporting pillars. These pillars primarily focus on proactive and preventive techniques to enhance equipment reliability. Here are the explanations of the TPM pillars:

Pillar	Definition	Function
Autonomous Maintenance	The operator is responsible for routine maintenance tasks, including cleaning, lubrication, and inspection.	Operators have greater “ownership” of their equipment.Increases the operator’s knowledge of their equipment.Ensures the proper cleaning of equipment.Identifies emerging problems.
Planned Maintenance	Use predicted and measured failure rates to schedule maintenance tasks.	Reduces unplanned stop-time events significantly.Enables planned maintenance during equipment downtime.Improves control over wear-prone and failure-prone parts to reduce inventory.
Quality Maintenance	Detect and prevent design errors in the production process. Implement Root Cause Analysis to eliminate recurring sources of quality defects.	Target quality issues by focusing on improvement projects that directly eliminate significant sources of defects.Reduce the number of defects.Catch defects early to reduce costs and avoid unreliable inspections for defect detection.
Focused Improvement	Encourage small employee groups to work together proactively, aiming for regular and incremental improvements in equipment operation.	Cross-functional teams identify and resolve recurring issues.Companies combine their collective talents to create engines for continuous improvement.
Early Equipment Management	Utilize your knowledge and practical understanding of manufacturing equipment gained through TPM to enhance new equipment designs.	New equipment achieves planned performance levels faster, thanks to reduced startup issues.Simplified and more resilient maintenance is possible through practical reviews and employee involvement before installation.
Training and Education	Operators, maintenance personnel, and managers must fill knowledge gaps to achieve TPM goals.	Operators acquire skills to maintain equipment regularly and identify arising problems.Maintenance personnel are trained in proactive and preventive maintenance techniques.Managers receive training in TPM principles and employee coaching and development.
Safety, Health, and Environment	Maintain a safe and healthy work environment.	Enhances workplace safety by eliminating potential health and safety risks.Focused on achieving an accident-free workplace.
TPM in Administration	Uses TPM techniques to improve administrative functions.	Extend TPM benefits beyond the factory floor by tackling waste in administrative functions.Improve production by optimizing administrative operations such as order processing, procurement, and scheduling.

Key measures

The leading indicators of engine effectiveness include:

• Availability.

Availability = (loading time – downtime)/loading time

• Performance efficiency (measuring efficiency while the engine runs).

Performance efficiency = (net operating time – lost time)/(net operating time)

• Overall Equipment Effectiveness (OEE) is a metric that measures the percentage of planned production time that is genuinely productive.

OEE’s creation is to help TPM initiatives by precisely tracking progress towards achieving “perfect production.

• OEE’s creation is to help TPM initiatives by precisely tracking progress towards achieving “perfect production.
• A 100% OEE score indicates an ideal output.
• For a discrete manufacturer, a world-class OEE score is 85%.
• 60% is a reasonably typical OEE score for discrete manufacturers.
• Producers without TPM or lean programs often have OEE scores as low as 40%.

OEE = availability × performance efficiency × quality level

Accurate data holds great significance. However, certain managers perceive the time workers dedicate to measure machine performance as a waste. Certain companies only document equipment failure downtime if it surpasses 30 minutes.

Maintenance is all about staying focused. We need accurate records of the equipment’s operation to ensure things run smoothly. It’s not enough to know when things are down. Luckily, technology has made advancements, and we can easily access this data using ERPs.

Most companies can generate valuable data such as Mean Time to Repair (MTTR), Mean Time Between Failure (MTBF), and more with a small investment. By pinpointing hotspots, we can address the root cause of equipment problems by implementing manual processes or adding extra buffers.

Read more: Lean Manufacturing: Definition & 3 Advantages to Utilize

Six big losses

TPM involves engaging all team members to eliminate six major disadvantages that reduce machine effectiveness. These disadvantages include:

Downtime

Source: Dennis, P. (2017); Lean Manufacturing Simplified; bathtub curve

Defects

5. Process defects encompass scrap and deficiencies that necessitate repair.
6. The yield experiences a decrease during machine startup until it reaches steady production.

The machine loss pyramid

The concept of the Machine Loss Pyramid stresses the importance of spotting small, hidden losses at an early stage. Herbert Heinrich’s book, Industrial Accident Prevention, states that for each severe injury, there are ten minor injuries, 30 incidents of property damage (without personal injuries), and 600 near misses. The same idea applies to machine losses, as illustrated in the following pyramid:

What do the numbers reveal? 

• Breakdowns or damages (when something stops working correctly) are just the starting point.
• Even short periods of downtime (when something isn’t working as well as it should) can be more important than the actual damage.
• There might be many small and hidden problems for each significant issue.
• We need to keep track of and stop many of these small and hidden problems to prevent crashes.

Noticing early signs of accidents, like minor, hidden issues, is essential for preventing damage and improving our understanding of the equipment. TPM actively pays attention to these problems and takes action before they become prominent. 

Masaaki Imai talks about a production unit at the Tokai Rika plant in Japan where engineers are encouraged to report any small or hidden issues. They keep track of these problems and involve the whole team. Toyota Cambridge also does something similar: Take Action on Accident Prevention. This approach has helped them become a top leader in machine safety and effectiveness.

Small group activity

Involve production team members in checking, reporting, and correcting hidden failures and minor downtimes. Where possible, actively engage the production team in these tasks.

Create check sheets for each major piece of equipment and system to track and display their condition. Refer to the provided image for a generic TPM check sheet.

Source: Dennis, P. (2017); Lean Manufacturing Simplified; TPM Checksheet.

We involve our team members in kaizen circles, practical kaizen training, and other small group activities to strengthen the identified hotspots. This approach enables us to:

• Improve OEE and extend machine life
• Enhance team members’ capabilities and streamline processes
• Foster a greater sense of respect for humanity

The following figure summarizes the TPM stages, from stabilizing to improving the design. These stages help streamline the production process and enhance its stability.

Summary

TPM holds the key to production stability by emphasizing proactive and preventive maintenance. Its primary goal is to maximize equipment operational efficiency and eliminate the six significant losses that hinder productivity.

Companies must actively involve employees in short-term and long-term initiatives to achieve sustainable TPM. They should establish a shared vision for the company’s future and communicate the benefits to employees. In the next chapter, we’ll explore another cornerstone of the House of Lean Production — standardized work.

Reference

Dennis, P. (2017). Lean production simplified: a plain-language guide to the world’s most powerful production system. Crc press.