What is Breakdown Loss?

Breakdown loss refers to the loss of equipment downtime involving part replacement, and the loss time is calculated as 'number of downtime × repair time.' While reducing repair time is important, the primary goal here is to prevent the same breakdowns from occurring again. Understanding the cause of the breakdown that has already occurred and eliminating those factors leads to the prevention of breakdowns in the future.

Deployment of Breakdown Loss Improvement Steps

Here is the deployment of the 7 steps for reducing breakdown losses in the following table, along with an explanation of the content of each step.

Step 1: Classification of Historical Breakdown Data

Equipment breakdowns can occur in many different ways, which often makes it difficult to determine where to begin improvement efforts. Therefore, Step 1 starts with the classification and organization of past breakdown data. This process reveals the weak points of the equipment and clarifies the specific breakdown modes that require improvement.

 

(1) Identifying Weak Points Through Breakdown Analysis

Breakdown analysis is the work of gathering information to select an improvement theme. The process involves classifying historical data on equipment parts' breakdowns and breakdown modes of the target equipment into a matrix (see the figure below).

Example: Breakdown Analysis Matrix 

The objective is to clarify weaknesses in equipment management by analyzing breakdown mode trends, location/parts, and frequency, in order to establish an improvement theme. Furthermore, this analysis provides the basis for achieving the target value by identifying which breakdown modes must be eliminated.

 

(2) Selection of Improvement Themes

To achieve high-level objectives, such as increasing the operational/equipment availability rate and reducing downtime loss, a specific target must be set for how much breakdown loss will be reduced. Furthermore, to meet the breakdown loss reduction target, it is necessary to clarify which breakdown modes must be reduced to zero. This is defined as a sub-improvement theme (hereafter, "sub-theme").

Sub-themes should be selected from the breakdown analysis matrix by identifying breakdown modes linked to weaknesses and recurring problems. The selection should be made with the objective of "never letting the same breakdown occur twice."

From Step 2 onwards, the process proceeds on a per-sub-theme basis (see the figure)

Figure: Proceeding by Sub-Theme

Step 2: Current Status Analysis

Before starting the current status analysis, here is an explanation of the causes of breakdowns. A breakdown occurs when stress (load) exceeds strength. In other words, factors such as neglected stress, the progression of deterioration, and insufficient strength lead to breakdowns.

 

The following five factors can be considered the causes that lead to breakdowns (see the figure below):

1. Lack of basic conditions

2. Failure to comply with operating conditions

3. Neglected deterioration

4. Weaknesses in design

5. Lack of skill

Investigating breakdown mode to determine the cause, in step 2.

(1) Clarification of the Phenomenon

For some breakdowns, the cause is immediately apparent, such as operator error or the neglect of temporary countermeasures. In most cases, however, the cause is unclear.

Therefore, it is important to identify the specific breakdown mode, which represents the phenomenon of the breakdown.

Especially in the moments following a breakdown, the actual site and all physical elements (the Genba, Genbutsu) offer a wealth of information. This concept of Genbutsu includes not just the machine itself, but also processed materials, the surrounding environment, and any other physical evidence. It is essential to thoroughly gather all factual data needed to investigate the cause. This includes collecting key details, such as the exact condition of the equipment when it stopped and whether any signs or symptoms appeared beforehand.

Additionally, damaged components/parts often tell a detailed story about the cause of a breakdown.

Through the disassembly and investigation of the physical part (Genbutsu), it is important to clearly identify which component/part failed and the specific type of breakdown mode that occurred.

During the investigation into the cause of a breakdown, multiple breakdown modes may be identified.

In such cases, it is crucial to technically determine which breakdown mode was the initial trigger and to proceed with the root cause investigation from that point.

It is also necessary to investigate whether the failed component was inspected and replaced properly, and to compare its replacement history against its expected lifespan. Understanding the lifespan makes it possible to determine if the breakdown was caused by neglected deterioration, accumulated deterioration, or an inherent design weakness. 

Additionally, it is also possible and important to determine if a skill deficiency was a contributing factor by investigating whether the previous repair was performed correctly and if any operator errors occurred before the stoppage.

When setting countermeasures for past breakdowns, analysis would typically start with stored replacement parts, but in most cases, the actual physical component (Genbutsu) is no longer available. In such situations, the only resource to rely on is the breakdown data. It is important that this data preserves as much situational information as possible, clearly identifying the breakdown mode and including supplementary materials like photographs.

 

(2) Understanding Equipment Structure and Function

Once the breakdown mode is clarified, you might want to jump directly into a root cause analysis. However, it is critical not to overlook any potential contributing factors. First, it is essential to create mechanical drawings of the equipment and components related to the breakdown, using resources like blueprints and system configuration diagrams. This helps in understanding the function and structure, including actual movements, the transmission of force, how loads/stress are applied, and the relationships between parts.

 

(3) Creating a List of Inspection Items

To prevent breakdowns, each functional component must be in its correct condition.

Based on the mechanical drawings created for the parts that fail as well as surrounding and related parts, it is necessary to understand their "ideal state" from the perspective of fundamental principles. This understanding is then used to generate a comprehensive list of inspection items, including all sufficient conditions.

At this stage, it is important to exhaustively identify all inspection items, including all sufficient conditions, without yet considering their relationship to the specific breakdown mode.

 

(4) Shopfloor Investigation

The actual condition of the components is investigated against the list of inspection items that was created based on principles. In other words, a one-by-one investigation on the shop floor is conducted to determine if the basic requirements for related functions are being correctly met and if operating conditions are proper. Any non-conformities are then identified. In many cases, a failure to follow established procedures causes accumulated deterioration, which ultimately leads to a breakdown.

In case a breakdown occurs despite all operating conditions being met and no other problems being found, it is likely that there is an issue with the design.

By this stage of the investigation, it is possible to infer which one of the five breakdown causes applies. However, the cause of a breakdown is not necessarily limited to a single factor. Depending on the non-conformities discovered, multiple causes might be involved. The diagram below illustrates the procedure for Improvement Steps 1 and 2.

 

Step 3: Mechanism Analysis

The non-conformities identified during the on-site investigation (Genba Genbutsu) are classified by the five breakdown causes to verify if they could be the cause of the current breakdown mode. The relationship between the breakdown mode and the phenomenon (the breakdown itself) is also analyzed by estimating the mechanism (process) of the breakdown. (See Figure 3.1.6).

 

(1) Identify Acting Stresses

Parts deteriorate because some form of stress (load) is applied to them.

Therefore, it is essential to clarify what stresses are generated by the non-conformities discovered during the on-site investigation (Genba Genbutsu).

For example, if there is a defect related to inadequate basic conditions, such as "insufficient lubrication," the stress is identified in a sequence like: insufficient lubrication leads to a break in the oil film, resulting in an increase in frictional force.

 

(2) Estimate the Process from Stress Occurrence to the Breakdown Mode

The relationship between the stress identified from the non-conformity and the resulting breakdown mode is examined one by one.

 

(3) Estimate the Process from the Breakdown Mode to the Occurrence of the Phenomenon (Breakdown)

Next, the process from the breakdown mode to the occurrence of the phenomenon (the breakdown) is estimated. This task becomes crucial when multiple breakdown modes are identified.

 

Step 4: Implementation of Countermeasures

Countermeasures are implemented for the non-conformities (the five causes) identified during the on-site investigation (Genba Genbutsu).

 

(1) Restoration of Defects

All locations of defects found through on-site and physical investigation must be fully restored and improved. This is because if defects are left unaddressed, the deterioration will worsen, which can affect other areas and potentially lead to new and different problems. 

 

(2) Countermeasures for Weaknesses

For any breakdown primarily caused by a design weakness, a deeper investigation into the root cause must be conducted.

Challenges will be resolved by examining whether the equipment is selected to be adapted for the acting stresses and whether sufficient strength is ensured to handle those stresses.

 

Step 5: Root Cause Analysis

The investigation into the cause of a breakdown is not complete simply by taking countermeasures against its primary cause.

It is essential to investigate the true underlying issues in operation and management, such as why the defect that led to the breakdown mode occurred and why it could not be prevented.

 

As shown above, it is important to ask the following questions:

In the case of basic or operating conditions, Why were the basic and operating conditions not maintained?

In the case of neglected deterioration, why was restoration not performed?

Why could an inspection not be carried out?

In the case of a design weakness, why was the component selection incorrect?

It is crucial to utilize the "Why-Why Analysis" in this way to thoroughly investigate down to the level of human behavior (see Figure 3.1.7).

In other words, the root cause of a breakdown is human action.

 

Step 6: Confirmation of Effectiveness

The effectiveness of breakdown countermeasures is not immediately apparent and must be evaluated over the long term. However, confirming the effects after implementing countermeasures is important. Based on the results of these countermeasures and their horizontal deployment, it is necessary to confirm how the occurrence of the breakdown mode has changed for the better.

 

Step 7: Standardization and Horizontal Deployment

In Step 7, the results from the steps up to Step 6 are standardized to establish a management system for preventing recurrence. Specifically, standards for daily inspections, periodic inspections, periodic maintenance, and the division of roles between Autonomous Maintenance and Planned Maintenance will be created.

 

It is important to horizontally deploy countermeasures to similar equipment and to those with similar parts. For any issues in design, manufacturing, or installation, these should also be reflected in new equipment by utilizing MP (Maintenance Prevention) information.

*In case you have questions/comments to JMAC or the author of this article, please contact us through the inquiry form. Click here to ask JMAC!

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●Author profile

Nobuhiro Otsuka, Chief TPM Consultant

After joining the Japan Institute of Plant Maintenance (JIPM), Nobuhiro has been working on projects to improve productivity, reduce costs, and improve quality in the metal products, electrical and electronic parts, automotive, food and beverage, pharmaceutical and medical products, and paper industries. Nobuhiro provides consulting support from both a Gemba (shopfloor) perspective and a management perspective. Supports many companies both domestically and overseas. Currently works on a wide range of projects including TPM, cost management/cost reduction, quality improvement, industrial engineering, factory layout planning, purchasing/procurement, etc.

Katsunori Kanegae, Chief TPM Consultant, Director of TPM Consulting Business

After working as a production engineer at an electrical manufacturer, Katsunori became a consultant. As an expert in production strategy, production methods, and equipment management, he has been supporting domestic and international manufacturing companies in productivity improvement, cost management, defect reduction, inventory reduction, and lead time improvement projects. His expertise extends to researching advanced equipment maintenance technology and working on digital transformation in equipment maintenance. He also has authored numerous articles on digital transformation.

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