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TPM (Total Productive Maintenance) emerged in Japan thanks to the efforts of the Japan Institute of Plant Maintenance (JIPM) as a system destined for achieving the elimination of so-called ‘six great losses’ of equipment, in order to facilitate the implementation of “Just in time” management.
By Santiago García Garrido
The Philosophy of TPM
TPM is a philosophy with the goal of eliminating production losses due to equipment failures, or in other words, keeping equipment maintained at such a level that they can operate at maximum capacity without unscheduled stops. This includes:
- Zero breakdowns
- Zero downtime
- Zero failures attributed to poor condition of equipment
- No loss of efficiency or production capacity due to this equipment
meaning can be found in its name. Total Productive Maintenance aims to provide maximum productivity.
The Fight Between Maintenance And Production
Traditionally maintenance has been seen as a separate and external part to the production process. TPM emerged as a way to integrate the maintenance department into the operation with the aim to improve productivity and availability of machinery. In a company that has implemented a TPM system all of the organization towards the upkeep of necessary machinery. It is based on five principles:
- Staff participation: From senior management to plant operators. The goal is for equipment maintenance to be thought about at all levels of the business.
- Corporate culture: The companies aim throughout all levels of employees should be to obtain maximum efficiency in the production system. ‘Global efficiency’ is pursued.
- Prevention: Management implements a system with the aim of eliminating losses due to down time before they happen.
- Management systems implementation for all aspects of production, including design and development, sales and management.
The Six Great Losses
The philosophy of TPM is that the stopping of a machine due to a breakdown or repair means that the plant is not running at full capacity. A machine which does not work at 100% of capacity or that manufactures defective products is intolerable to the company. The machine should be considered unproductive in all these cases, and appropriate actions should be designed to avoid them in the future. TPM identifies six sources of loss (called the ‘six great losses’) that reduce the effectiveness of production:
- Equipment failure: Producing unexpected loss of time.
- Commissioning and machine settings (or downtime) which delay the start of an operation.
- Idle, waits and minor stoppages (minor failures) during normal operation which cause loss of time, either by problems in the instrumentation, small obstructions, shift changes etc..
- Reduction of operation speed (the machine does not operate at full capacity), which causes production losses because the design speed of the process is not achieved.
- Defects in the production requiring the remake or replacements of components or parts.
- Loss of time associated with learning a new process, training etc.
Each of these can be a cause of low productivity so finding solutions to eliminate them and the means to implement these changes are a top priority. It is essential that the analysis is done by the production staff and maintenance staff together so that the changes don’t cause unexpected results.
Participation In Maintenance Tasks
From a practical point of view, implementing TPM in an organization means that maintenance is perfectly integrated into production. Therefore, part of the maintenance work has been transferred to production staff. Production staff should see equipment as theirs to look after as well, not as something that is looked after by someone else.
Maintenance is separated into three levels:
- Operator’s level, who will be responsible for operative maintenance tasks that are very simple, such as cleaning, adjustment, parameter monitoring and repairs to minor failings.
- Integrated technical level. Within the production team, there is at least one maintenance person who works with the production staff; he/she is just one of them. This person solves problems more significance, for which more knowledge is needed. This employee should be available quickly for mid-level repair work.
- For higher-level interventions, and scheduled overhauls that involve complex dis-assemblies, delicate adjustments, etc., the company has a maintenance department which is not integrated into the structure of production.
Operator’s involvement in maintenance tasks makes him better understand the machine and the installation he is operating, its characteristics and capabilities. Employees should work as a team, this facilitates sharing of experiences and mutual learning, and this improves personal motivation.
There is a fundamental difference between the philosophies of TPM and RCM: while TPM is based on the people and the organization being the center of the process, whereas RCM maintenance is based on failure analysis, and preventive measures to be taken to avoid them before they happen.
Implementing TPM In A Company
The Japan Institute of Plant Maintenance (JIPM) developed a seven-step method aimed at achieving the required changes in personal attitude and the adoption of TPM through a company. The steps to develop this change of attitude are:
Phase 1. Initial Cleaning
In this phase a thorough cleaning of the machine is done to remove visible dust, dirt and grease etc. Equipment is also fully repaired, given oil changes etc.
Phase 2. Measures to discover the causes of dirt, dust and faults
After cleaning the machine the aim is for it to not get dirty again. Causes of dirt, dust and irregular operation must be avoided (oil leaks, for example), access to cleaning products and lubricants must be improved and available in easy to access places.
Phase 3. Preparation of procedures for cleaning and lubrication
A procedure is then created that allows for the rapid cleaning, the replacement of oil/grease and necessary services to be done as quickly and efficiently as possible.
Phase 4. General inspections
Once the staff are responsible for cleaning, lubrication and minor adjustments of their machinery you should train the production personnel so that they can inspect and check the equipment for minor failures and sources of potential failures in the future.
Phase 5. Autonomous inspections
In this phase, the ranges of maintenance or operation maintenance are prepared. In this phase checklists of the machines are prepared by the operators themselves, and then they are put into practice. This is the stage where there is real implementation of periodic preventive maintenance performed by the personnel operating the machine.
Phase 6. Optimization and autonomy in the activity
The last phase aims to develop a culture of continuous improvement across the company: It registers systematically the time between failures, analyzes them and proposes solutions. All this is promoted and led by the production team.
The time required to complete the program varies from 2 to 3 years. The transformation’s success depends on the emphasis put forward by upper management over the course of the changes and the push towards training and improvement at all levels of the company.
Hiring External Advice In The Transition To TPM
Some companies choose to hire an external company that specializes in the implementation rather than attempting it themselves. In general, a single advisor is usually enough to oversee the changes. In larger companies the changes may requires a full time specialist overseeing the changes but this is only likely if the company has many production lines. Typically, the counseling and mentoring process can be done part time. The expert will spend more time on site at first and then gradually transferring the process back to leadership as they gain more experience.