OBJECTIVE ZERO STOP/BREAKDOWN, ZERO FAULTS, ZERO ACCIDENTS
To be efficient, a site needs a reliable production tool. The TPM approach or Total Productive Maintenance is therefore centred on the machine. When a company plans to work Just In Time and Zero Stock, it must not forget that it will not be able to meet the deadlines it has announced to its clients if it is not certain that :
The machines and tools will be available during all the operating time.
The quantities launched will be obtained (good products).
When do we have to use TPM, Total Productive Maintenance?
TPM should be reserved for equipment for which the cost of underperformance is higher than the cost of obtaining performance. The implementation of the TPM is done in stages following a structured and rigorous methodology. It must start with a PILOTE project. This makes it possible to train the first level management, the sector manager and support functions such as methods and maintenance right from the start. On this basis and as soon as the significant results are obtained, the TPM can begin to be deployed in the rest of the site. So it's a long-term job.
Minimize losses with TPM
By observing the day of a machine, one realizes that it does not work during all the opening time of the workshop. There are operations that require shutdown or at least unproductive phases such as series changes, recharging, maintenance, preheating... This introduces the notion of gross running time.
During the gross running time, one would expect a production equal to this time divided by the nominal rate. However, production records quickly show that this is not the case! This does not take into account all the hazards affecting performance: breakdowns, deviations, micro-stops... and the actual rate which is very often or even always lower than the nominal rate.
The gross operating time cut of the lost time gives the actual operating time, or net operating time. Unfortunately the losses do not stop there. It is obvious that only good parts can be sold to customers. This is the useful operating time.
This diagram below, highlights the proportion of the really useful time compared to the total opening time according to the losses. Your company's profit is not assured with such a waste! It is important to notice that each "loss" finds its cause in an area that will interest maintenance. To increase productivity, we must therefore reduce all these losses. It is possible to know with precision the actions to carry out thanks to the OEE, Overall Equipment Effectiveness.
Potential opening time
Real opening time
Plant capacity not used
Gross operating time
Planned stops
Net operating time
Breakdowns, performance losses
Useful operating time
No quality
The ideal would then be :
Zero failure / stop
Zero fault
Zero accidents
In practice this amounts to :
Maintain the equipment in good condition, repair, clean and lubricate it
Penalize production as little as possible
Consider all aspects of maintenance
Les 8 piliers de la TPM
In 1989, the JIPM defined 8 pillars on which a TPM approach is based to achieve a high level of industrial performance.
They can be divided into two families of 4:
The first family aims to improve the efficiency of the production system
Autonomous management and maintenance of equipment, elimination of waste / improvements on a case by case basis, planned maintenance and improvement of knowledge and know-how
The second goes beyond the strict framework of production towards services and related functions
Safety, working conditions and environment, quality control (maintenance), control of product and associated equipment design, efficiency of related services or "TPM in offices".
According to the sources and authors, the number and denomination of the pillars vary. The TPM can be considered as a building with the 5S as foundation and the 8 pillars. The solidity of the whole is linked to the quality of the foundations (5S). If a minimum number of pillars is installed, the building holds. Unlike, if a few pillars fail, the building can still survive. It is therefore not necessary to have all the pillars, nor that they are of identical size/strength to obtain results thanks to the TPM.
Pillar 1
Independent equipment management and maintenance
This pillar considerably increases the skill level of the operators so that they are autonomous to take care of maintenance and small maintenance interventions. The objective is to respond to the need for reactivity in the event of malfunction and to develop the autonomy of the teams. It involves, empowers and motivates operators more and above all frees expert technicians from maintenance for preventive interventions, improvement...
Pillar 2
Elimination of waste and improvement on a case-by-case basis
The method is to understand how the equipment affected by the loss works. We're analyzing the drifts. All waste and causes of loss of efficiency are targeted. The search and elimination of the root cause must definitively eliminate the malfunctions. The indicator and the OEE are its components which after analysis will focus the improvement actions...
Pillar 3
Planned maintenance
Planned maintenance favours preventive or even conditional maintenance. It aims at reducing or even eliminating breakdowns, reducing costs, avoiding the use of unplanned overtime, managing spare parts, etc.
Pillar 4
Improving knowledge and skills
If we want to establish and develop new working methods, there are necessarily new skills to acquire. It is therefore a matter of managing knowledge by first making an inventory and then establishing training needs, planning training with emphasis on sponsorship (an insider will train a beginner). Training may be differentiated according to the personnel targeted; operators to be informed, operators to be involved, members of an autonomous group, members of the coordination committee.
Pillar 5
Control of product design and associated equipment
The objective is, above all, to avoid repeating the mistakes of the past, to retain all the lessons learned during problem solving projects and to integrate improvements in the choice of new equipment (design, ease of operation, maintainability, etc...). By structuring the development of new projects according to this principle, development can be greatly reduced or even eliminated and costs are reduced.
Pillar 6
Quality control
The objective is to maintain and improve product quality, by seeking the stability of equipment and processes. We seek to eliminate the causes of non-quality, so that every minute produces a "good" product. Product quality control is based on the following actions :
Systematically measure in order to operate equipment that does not generate quality defects
Check that the measured values are within the reference ranges (tolerances, control limits, monitoring limits, etc.)
Monitor changes of the measured values to predict the risk of faults occurring and act preventively on the equipment
Eliminate any unusual deterioration: production must have equipment for which only normal wear and tear persists
Pillar 7
Efficiency of related services or "TPM in offices".
This pillar applies to administrative and production-related services (warehouses, maintenance, etc.) and consists in building on the successes obtained in the workshops by methods, tools and approaches such as 5S. Their activities, if not conducted efficiently, can indeed affect production. Improvements include quality, costs, quantities and lead times.
Pillar 8
Safety, working conditions and environment
Within the context (official or not) of sustainable development and the regulations in force, this pillar aims to eliminate any potential cause of problems related to :
Safety, particularly at sites where most accidents occur
