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 the way of working "Just in time".
The philosophy of TPM TPM is a maintenance philosophy aimed at eliminating production losses due to equipment status, or in other words, keeping equipment in a position to produce at maximum capacity, the expected quality products, with no unscheduled stops. This includes:
The eternal fight between maintenance and production Maintenance has traditionally been seen with a separate and external part to the production process. TPM emerged as a need to integrate the maintenance department into the operation or production one to improve productivity and availability. In a company that TPM has been implemented, all the organization works on maintaining and improving equipment. It is based on five principles:
Six great losses Since the philosophy of TPM, it is considered that a machine stop for making a change; a breakdown in a machine; machine which does not work at 100% of capacity or that manufactures defective products; are intolerable situations which cause losses to the company. The machine should be considered unproductive in all these cases, and appropriate actions designed to avoid them in the future should be taken. TPM identifies six sources of loss (called the ‘six great losses’) that reduce the effectiveness because of interfering with the production:
Participation of the operator 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 have been transferred to production staff, who no longer feels the equipment like something that others take care of it, but as their own, they have to pamper and repair it, the operator feels the equipment as his. Maintenance involves differences in three levels:
There is a fundamental difference between philosophy of TPM and RCM: while the TPC is based on the people and the organization as the center of the process, the RCM maintenance is based on failure analysis, and preventive measures to be taken to avoid them, rather than on people. TPM implementation in a company The Japan Institute of Plant Maintenance (JIPM) developed a seven-step method aimed at achieving a change in attitude, which is essential to the success of the programme. The steps to develop this change of attitude are: Phase 1. Initial Cleaning In this phase, It is tried to clean the machine from dust and dirt, to leave all parts clearly visible. It is also implemented a lubrication programme, the machine components are fitted and an equipment commission is performed (all known failures are repaired) Phase 2. Measures to discover the causes of dirt, dust and faults After cleaning the machine it must not get dirty again and fall into the same state. Causes of dirt, dust and irregular operation must be avoided (oil leaks, for example), access to clean and lubricate difficult places must be improved and to reduce the time needed for these two basic functions (clean and lubricate) is sought. Phase 3. Preparation of procedures for cleaning and lubrication In this phase appear again two primary maintenance functions or first level functions, assigned to the production staff: at this stage are prepared standard procedures in order that the activities of cleaning, lubrication and minor adjustments of the components can be done in short time. Phase 4. General inspections Once you get that staff be responsible for cleaning, lubrication and minor adjustments, you should train the production personnel so that they can inspect and check the equipment for minor failures and failures in gestation process, and of course, solve them. Phase 5. Autonomous inspections In this fifth phase, the ranges of autonomous 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. Order and Harmony in the distribution Activities standardization and procedurisation is one of the essences of Total Quality Management (TQM), which is the philosophy behind both the TPM and the JIT. This establishes procedures and standards for cleaning, inspection, lubrication, maintenance of records which reflect all maintenance and production activities, management of tools and spare parts, etc. Phase 7. 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 programme varies from 2 to 3 years, and usually is developed as follows: Management announces to all the company the decision to implement TPM. The program's success depends on the emphasis put by the General Manager in his announcement to all staff. It makes a massive campaign of information and training to all levels of the company so that everyone understands clearly the concepts of TPM. All possible means are used, such as lectures, posters, bulletin boards, etc.., So a favourable atmosphere is created to start the program. Organizations to promote TPM are set up, such as a Management Committee, Departmental Committees and Task Groups to discuss each topic. Basic policies and goals that will state in the TPM programme are defined and issued. To this objective a survey is conducted for all company operations to measure the real effectiveness of the operation team and know the situation with regard to the "6 great losses". In conclusion, goals are set and a programme to fulfil them is proposed. A master plan for TPM development is defined, which results in a programme of all activities and stages. Once the previous preparatory stage is finished, the "official party" comes to the TPM programme a starting ceremony attended by the highest authorities of the company and with guests from all areas. Begins the analysis and improvement of the effectiveness of each of the equipment of the plant. An information system is defined and is established to record and analyze data for reliability and maintainability The system is defined and autonomous maintenance groups are formed to start their activities immediately after the "official party". At this time the maintenance department will work to increase considerably due to the requirements generated by the groups from areas of production. A scheduled maintenance is implemented at the maintenance department. It is started the training for operators and maintainers to improve their knowledge and skills. It creates the improvement system of the plant equipment that allows to implement the ideas of change and design modifications to improve reliability and maintainability. Finally it is consolidated the full implementation of TPM and you get a high level of team effectiveness. With this purpose, incentives to domestic achievements of TPM programme should be created in the various departments of the company. The hiring of external advice in the process of TPM implementationThe hiring an external company to implement TPM, means hiring a specialist consultancy service responsible for implementing in consecutive phases the total productive maintenance. In general, a single advisor is usually enough. Sometimes counselling takes full time, but this is only profitable if the company has many production lines. Typically, counselling and mentoring process can be done at part time, spending more time at first and gradually leaving the on the production staff hands, the leadership of the implementation project.
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RCM or Reliability Centred Maintenance is one technique more within the possibilities to develop a maintenance plan in an industrial plant that it has some important advantages over other techniques. Initially, it has been developed for the aviation sector, where the high costs derive from the systematic replacement of parts threatened the airlines profitability. Later, this technique has been transferred to the industrial field, after establishing the excellent results it has had in the aeronautical field.RCM was firstly documented in a report written by FS Nowlan and H.F. Heap and published by the Department of Defense of United States in 1978. Since then, the RCM has been used to help to formulate strategies for managing physical assets in virtually all areas of organized human activity, and in virtually all industrialized countries in the world. This process defined by Nowlan and Heap has been the basis for various application documents in which the RCM process has been developed and refined in subsequent years. Many of these documents retain key elements of the original process. However, the widespread use of the name "RCM" has led to the emergence of a large number of failure analysis methodologies that differ significantly from the original, but its authors also called "RCM". Many of these other processes fail to achieve the objectives of Nowlan and Heap, and some are even counterproductive. In general try to abbreviate and summarize the process, leading in some cases completely denature.
As a result of international demand for a rule setting minimum standards for a failure analysis process can be called "RCM" emerged in 1999, the SAE JA 1011 standard and in 2002 the SAE JA 1012 standard. These rules not intend to be a guide or manual procedures, but merely set out, as noted, criteria that should satisfy a methodology that can be called RCM. Both standards are available at www.sae.org website The methodology described in these articles matches these rules.
The fundamental objective of a suitably managed department is not the pressing solution of failures that occur. Unfortunately, this seems to be the objective of many installations. In fact, the objectives are wider and more varied.
Maintenance department of an installation has six objectives which must mark and run its work:
Secureness objective Many of the accidents that occur in the installations happen because these suffer from functioning failures that turns them insecure. The vast majority of the installations are do manged according to manufacturer's instructions and the engineering that designed them, and safety standards established with the help of risk analysis are fulfil. These are installations with a probability of accident almost negligible. Only a failure in a component, equipment or system, changes the controlled conditions and makes the probability of an accident unacceptable. Thus, the first maintenance objective must assure that degradation that usage and time make on equipment outweigh enough to not risk people’s security. Environmental objective Likewise, many of the environmental accidents and incidents that cause a negative impact in environment happen due to an unexpected functioning of these, occurring from a failure in a component, equipment or system. The majority of the installations are do manged according to manufacturer's instructions and the engineering that designed them, and standards established with the help of environment risk analysis are fulfil. These are installations with a probability of environmental accident or incident almost negligible. In the majority of the installations, only a failure in a component, equipment or system, changes the controlled conditions and makes the probability of an environmental accident unacceptable. Therefore, the second objective of maintenance must assure that degradation that usage and time make on an equipment outweigh enough without risk of the environment suffering a negative impact. Availability objective The availability of an installation is defined as the proportion of time when that installation has been in willingness of production or been used, regardless of whether it has or has not been used, for reasons beyond its technical condition. The most important maintenance objective is to guarantee that the installation is in disposition of produce or be used a certain minimum number of hours per year. It is an error to think that the objective of maintenance is to achieve the maximum availability possible (100%) as this can become very expensive. Thus, achieving the marked availability objective with a certain cost is generally enough. As will be seen further on, availability is an indicator that offers great possibilities of reckoning. Therefore, only for certain installations that operate intermittently (plants which produce in campaign, plants or installations that only function in certain periods) the objective of availability focuses on the hours reckon to produce, and the availability or not of the plant when it is not require to produce is relatively trivial. The definition of availability calculation estimation plays a crucial role in judging if the department of maintenance of any industrial installation is doing its job accurately or an improvement is needed. The principal factors to bear in mind in the estimation of availability are the following:
There are several calculation estimations for this indicator that will be seen further on, on the chapter dedicated to maintenance indicators. It is crucial to highlight that the IEEE develop an specific rule for the reckoning of the installation that can be extrapolated to other type of installations, trying to avoid partial interpretations that may benefit some part at the expense of another (contractor owner, and so). Reliability objective Reliability is an indicator that measures the capacity of a plant to achieve the production plan intended. In an industrial installation, it usually refers to fulfilment of the production intended, and, in general, understood by both internal and external clients. The achieving of this load program may have consequences like financial penalties, and hence the importance of measuring these value, and bearing it in mind when designing the maintenance management of an installation. Factors to keep in mind for the reckoning of this indicator are two:
The objective of maintenance seeks this parameter to always be above an intended value established in the design techno-economical design of the plant, and its value is frequently quite high (same or higher than 99,0%). A well-managed installation ought not to have any problem to reach this value. The shelf life of a plant. The fifth great maintenance objective is to guarantee a long shelf life for the installation. In other words, the industrial plants must present a condition of deterioration consonant with what intended, in a way that neither the availability nor the reliability nor the maintenance cost could be out of the objectives settled for a long period of time, usually in accordance with the repayment term of the plant. The lifespan of a typical industrial installation is placed between 20 and 30 years, when the benefits of the plant and its maintenance objectives must always be inside the values intended. A bad-managed maintenance, with a low proportion of hours intended to preventive tasks, with poor budget, lack of means and personnel, and based in provisional repairs, provokes the rapid degradation of any industrial installation. It is remarkable of bad-managed plants that although little time has passed since its initial start, the visual aspect does not correspond to its youth (in terms of lifespan). The achieving of the budget. The objectives of availability, reliability and shelf life cannot be obtain at any cost. The department of maintenance has to achieve the objectives intended adjusting its expenses to what was settled in the annual budget of the plant. As said in the previous section, this budget has to be reckon with extreme care, since a lower budget than the plant needs worsen irretrievably the results of production and limit the shelf life of the installation; on the other hand, an upper budget than the installation needs worsen the operating account results. 1.The difficulty of finding a practical application to the types of maintenance This division of types of maintenance has the disadvantage of that each equipment needs a mix of each of these maintenance types, so that we can not think of applying one of them to a particular equipment. Thus, for a particular engine, we will take care of lubrication (periodic preventive maintenance); if it is required, we will measure the vibrations or temperature (predictive maintenance);we also may qualify for an annual tune-up (overhaul) and we will repair the faults coming up(corrective maintenance). The most suitable mixture of these types of maintenances will dictate to us strict reasons linked to the cost of production losses in a stop that equipment, the repair cost, environmental impact, safety and quality of a product or a service, among others. The disadvantage, therefore, of the anterior division is that it is not able to give a clear answer to this question: Which is the maintenance that should be applied to each of the equipment that make up a particular plant? To answer this question it is convenient to define the concept of Maintenance Models. A Maintenance Model is a mixture of the previous types of maintenance in certain proportions, and it responds appropriately to the needs of a particular equipment. We think that every equipment will need a different mix of different types of maintenance, a particular mix of tasks, so that maintenance models will be as many as existing equipment. But this is not entirely correct. 4 of these mixtures can be clearly identified, and they can be supplemented with two types of additional tasks, as we shall see. 3. Maintenance models Each of the models presented below include several of the previous types of maintenance at the indicated rate. Moreover, all of them include two activities: visual inspections and lubrication. This is because it is demonstrated that these tasks realization in any equipment is profitable. Even in the simplest model (Corrective Model), in which virtually the equipment is left on its own and we do not deal with it until a fault occurs. It is advisable to observe it at least once a month, lubricate it with suitable products to their characteristics. Visual inspections virtually no cost money (these inspections will be included in a range where we have to look at other nearby equipment, so it will not mean we have to allocate resources specifically for this function). This inspection allows us to detect faults in an early stage and its resolution will generally be cheaper as soon as detected. Lubrication is always profitable. Although it does represent a cost (lubricant and labour), it is generally so low that it is more than warranted, since a malfunction due to a lack of lubrication will always involve a greater expense than the corresponding to lubricant application. With this remark, we can already define the various possible maintenance models. A. CORRECTIVE MODEL This is the most basic model, and includes, in addition to visual inspections and lubrication mentioned previously, the arising breakdowns repair. It is applied, as we will see, to equipments with the lowest level of criticality, whose faults are not a problem, economically or technically. In this type of equipment is not profitable to devote more resources and efforts. B. CONDITIONAL MODEL It includes the activities of the previous model, and also this model carries out a series of tests that will determine a subsequent action. If after testing we discovered an anomaly, we will schedule an intervention; on the contrary, if everything is correct, we will not act on the equipment. This maintenance model is valid in equipment not to very used, or for equipment that despite being important in the production system the probability of failure is low. C. SYSTEMATIC MODEL This model includes a set of tasks we will perform no matter what is the condition of the equipment , also we will perform some measurements and tests to decide whether to carry out other tasks of greater magnitude, and finally, we will repair faults that arise. It is a model widely used in equipment of medium availability, of some importance in the production system whose failures cause some disruption. It is important to note that equipment subjected to a systematic maintenance model does not have to have all its tasks with a fixed schedule. Just a equipment with this model of maintenance can have systematic tasks that are carried out regardless of the time it have been operated or state of the elements on which it works. It is the main difference with the previous two models in which to perform a maintenance task should be some sign of failure. An example of equipment subjected to this maintenance model is a discontinuous reactor, in which the tasks that must react are introduced at once, the reaction takes place, and then the reaction product is extracted before making a new load. Regardless of this reactor is doubled or not, when operating should be reliable, so it is warranted a series of tasks regardless of whether any signs of failure have been arose.Other examples:
It is the most demanding and exhaustive model of them. It is applied to that equipment that under no circumstances may suffer a breakdown or malfunction. These are equipments to whom are also required very high levels of availability, above 90%. The reason for such high level of availability is generally high cost in production due to a fault. With a demand so high, there is no time to stop the equipment if the maintenance requires it (corrective, preventive, systematic). To maintain this equipment is necessary to use predictive maintenance techniques that allow us to know the status of the equipment when is working, and scheduled shutdowns, which supposes a complete overhaul, with a frequency usually annually or higher. This review will replace, in general, all parts subject to wear or failure probability over the years (parts with a lifetime less than two years). These reviews are prepared well in advance and not have to be exactly the same every year. Since in this model the corrective maintenance is not included, that is, the aim should be zero breakdowns on this equipment; usually there is no time to properly address the issues that occur, being desirable in many cases quick provisional repairs that will maintain the equipment working until the next overhaul. Therefore, the Annual Overhaul must include the resolution of all those provisional repairs that have had to be made throughout the year.Examples of this model of maintenance may be:
4. Other considerations When designing the Maintenance Plan should be taken into account two important considerations affecting some equipment in particular. Firstly, some equipment are subjected to legal rules that regulate their maintenance, forcing them to perform certain activities with an established frequency. Secondly, some of the maintenance activities can not be performed with the regular maintenance equipment (either their own or hired) because it requires knowledge and / or specific resources that are only up to the manufacturer, distributor or a specialist team. These two aspects should be assessed when trying to determine the maintenance model that we should apply to an equipment. A. LEGAL MAINTENANCE Some equipment are subjected to rules or regulations by the Administration. Above all, there are equipment that are hazardous to people or the environment. The Administration requires the completion of a series of tasks, tests and inspections, and some of them must be performed by companies duly authorized to carry them out. These tasks must necessarily be incorporated into the Maintenance Plan of the equipment, whatever model you decide to apply.Some of the equipment subjected to this type of maintenance are:
When we talk about a specialist, we refer to an individual or a company specialized in a particular equipment. The specialist may be the equipment manufacturer, importer’s technical service, or a company that has specialized in a particular type of intervention. As we said, we must turn to a specialist when:
The subcontracted maintenance to a specialist is usually the most expensive alternative, as the company offering it is aware that not compete. The prices are not market prices, but monopoly prices. You should try to avoid it as far as possible by cost increase and higher external dependence that it involves. The most reasonable way to avoid this is to develop a training plan that includes specific training for those equipment that do not have enough knowledge also acquired the necessary technical means. Traditionally, 5 types of maintenance have been distinguished, which are differentiated by the nature of the tasks that they include:
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