Autonomous Maintenance

Autonomous maintenance is a cornerstone of the TPM (Total Productive Maintenance) methodology, enabling operators to take on inspection, cleaning and basic maintenance tasks, thereby reducing breakdowns and improving equipment reliability

Introduction

TPM is a system designed to maximise operational efficiency, taking into account the entire lifecycle of equipment. It involves all sectors of the organisation, engages all employees, and is implemented through teamwork on the shop floor.

TPM was developed by the Japan Institute of Plant Maintenance (JIPM) based on concepts introduced to Japan, notably the Preventive Maintenance approach developed at General Electric. The earliest recorded applications began precisely with the inclusion of machine operators in basic maintenance tasks, a practice that came to be known as Autonomous Maintenance.

What is Autonomous Maintenance?

Autonomous Maintenance aims to establish, from an equipment perspective, a well-organised system where any deviations from the norm are quickly detected. From the operators’ perspective, it aims to enhance their knowledge and skills so that they are prepared to carry out tasks such as:

• Cleaning and inspecting equipment.

• Lubrication and simple adjustments.

• Early identification of faults.

  
  

As a result, operators become responsible for the proper functioning of the machines they use on a daily basis, fostering a culture of ownership and prevention.

The implementation of Autonomous Maintenance involves a shift in the way production and maintenance teams work, moving away from working in isolation and towards working in a complementary manner.

Benefits of Autonomous Maintenance

• Reduction in unscheduled downtime: problems are detected before they become critical failures.

• Longer equipment lifespan: regular maintenance prevents premature wear and tear

• Increased productivity: less time wasted on repairs

• Increased staff motivation: as they learn more about how the equipment works and the causes of the most common problems

Autonomous Maintenance: Implementation

The implementation of autonomous maintenance follows these steps:

1. Initial Cleaning

This first stage is a structured process aimed at restoring the machine’s basic condition and identifying faults. It includes activities such as removing dirt, identifying and rectifying faults.

Dirt has a number of negative consequences for equipment:

• Foreign particles that adhere to moving parts and cause excessive friction, vibration, wear, leaks, etc

• Conveyor belts blocked by foreign particles, hindering the supply of compone

• Quality issues due to contamination (e.g. decoration, injection moulding, electrical contacts)

• Difficulty in detecting leaks, wear, play, loose fittings, etc.

• Demotivation of operators

  
  

This initial task is not merely about cleaning, but rather about identifying and eliminating all types of contamination. Through cleaning, the operator gains a thorough understanding of the equipment, removing dirt, debris and faults that could compromise its performance. During cleaning, sources of contamination, worn parts, leaks, abnormal vibrations and other signs of deterioration are identified. Following cleaning, there is an opportunity to lubricate gears and moving parts of the equipment

Whenever possible, any faults detected should be repaired immediately. Faults that cannot be rectified straight away should be marked with a red label and included in a list of faults

A note on the growing use of IoT devices in machinery which, by collecting data such as vibration, temperature, pressure and energy consumption, enable faults to be identified even before a failure occurs. Information from these sources should be incorporated into the first stage of Autonomous Maintenance.

2. Countermeasures to sources of contamination and dificult acess

After the initial cleaning, it is necessary to ensure that the equipment remains clean and that access to cleaning, inspection and lubrication points is improved. This second stage focuses on removing the causes of dirt and improving ergonomics and safety to facilitate self-maintenance activities.

To this end, it is necessary to identify the sources of dirt and contamination:

• Internal to the process:

  • Chips, swarf, cutting fluid, flux, release agent

  • Material residues (sheet metal, plastic, rubber)

• External to the process and internal to the equipment:

  • Lubricating oil, hydraulic oil, solvents, water

  • Metal particles from parts in contact

  • Defective product

• External to the process and equipment:

  • Dust, moisture, smoke, workwear, insects

  • Waste from pallets, cardboard, components

    
    

Following this identification, it is necessary to define measures to reduce internal contamination within the process, improve access to hard-to-reach areas and install containment devices.

It is also necessary to improve the cleaning method, as the time available for cleaning is limited; it is therefore necessary to set time targets for these tasks:

Identify the necessary cleaning operations that have not been eliminated by containment measures or equipment improvements:

• Select cleaning tools suited to the operations

• Define a cleaning sequence that minimises operator movements

• Draw up a draft version of the equipment cleaning standard

This stage is crucial because it makes cleaning a sustainable practice, preventing it from becoming a repetitive and ineffective chore. Furthermore, it paves the way for the third stage, which involves standardisation.

3. Cleaning and Lubrication Standards

Once stages 1 and 2 have been completed, it is essential to ensure that best practices become standard procedures. The third stage of Autonomous Maintenance involves establishing clear standards for cleaning, lubrication and inspection, ensuring that operators carry out these tasks consistently and effectively.

The key points of this stage are as follows:

• Establishment of cleaning standards

• Establishment of visual standards: checklists, labels, colours and signage to indicate lubrication and inspection points:

Frequency and responsibles: Determine when and who carries out each task (daily, weekly, monthly) and, on that basis, draw up a cleaning, inspection and lubrication schedule

Example of Mainteance Plan

Maintenance Plan on Tablet

The technologies currently available also play an important role in the third stage of autonomous maintenance:

• Displays or apps provide information on the machine’s condition,

• Tablets or mobile phones can be used to support maintenance plans:

  • Guiding the operator through the inspection sequence

  • Enabling the collection of photos and the reporting of faults

  • Providing access to more detailed instructions (in video format, for example) in case of uncertainty regarding the execution of the task

• Elimination of paper-based documentation

4. Training for Autonomous Maintenance

In the previous stages, the basic condition of the equipment, which had deteriorated, was restored; sources of dirt were eliminated; access to maintenance points was improved; and standards for cleaning, inspection and lubrication were developed. This established the conditions necessary to prevent accelerated deterioration.

In stage 4, there is a strong focus on deepening operators’ technical knowledge and improving their ability to detect anomalies. At this stage, operators begin to carry out more detailed inspections, going beyond basic checks.

To this end, based on an analysis of the equipment’s structure and operation, it is necessary to:

• Define inspection categories

• Review inspection activities

• Determine the necessary skills

• Assess operators’ qualifications

• Establish the training programme

• Prepare training materials

• Train operators

The digital resources mentioned above can help to reduce training time. Short videos demonstrating how to carry out each task can be used, which simplifies the training process and gives operators an initial introduction to the task. These resources also allow the operations performed by each operator to be recorded, making it easier to monitor the training plan and validate skills.

Audits in Autonomous Maintenance

Self-monitoring audits are an essential part of the methodology, as they ensure that each stage is being implemented correctly and that operators are maintaining the defined standards. These audits serve as a mechanism for verification and continuous improvement.

Audits objectives:

• Assess whether the activities planned for each stage have been completed.

• Identify strengths and areas for improvement.

• Ensure progression to the next stage (not allow the team to move on to a stage until the previous one has been completed)

  
  

How are the audits made:

• Step-by-step checklist: each stage of Autonomous Maintenance has specific criteria (e.g. initial cleaning, elimination of sources of dirt, standardisation).

• Direct observation at the workstation: checking the condition of the equipment, visual standards, records and operator involvement.

• Scoring or grading: a scale (e.g. 0 to 100%) is usually used to measure compliance.

• Immediate feedback: auditors communicate the results and suggest corrective actions.

• Action plan: definition of improvements before the next audit.

• Frequency

  • Monthly or quarterly, depending on the stage of the TPM project.

• Internal audits (conducted by the team) and external audits (conducted by TPM specialists or consultants).

KPIs

To measure the impact of autonomous maintenance, indicators such as the following can be used:

• OEE (Overall Equipment Effectiveness): measures the overall effectiveness of equipment (availability, performance and quality).

• MTBF (Mean Time Between Failures): average time between failures, indicating reliability.

• Number of faults detected by operators: an indicator of the effectiveness of autonomous inspections.

• Percentage of autonomous tasks completed: measures operators’ adherence to maintenance routines.

• Reduction in unscheduled downtime (%): assesses the direct impact on production continuity.Maintenance cost per unit produced: demonstrates financial gains following implementation.

Conclusion

Autonomous Maintenance is not merely an operational practice, but rather a cultural shift that transforms the relationship between people and equipment. By involving operators in cleaning, inspection and basic maintenance, an environment of greater responsibility, knowledge and prevention is created. This approach, integrated into the TPM philosophy, helps to reduce faults, increase reliability and improve productivity, fostering a genuine culture of continuous improvement.

Implementing all stages of Autonomous Maintenance requires discipline, training and support, but the results justify the investment: fewer stoppages, greater safety and more motivated teams. Ultimately, maintenance ceases to be seen as a cost and becomes a strategic factor for competitiveness.