MAINTENANCE & LOGISTICS T.P.M TOTAL PRODUCTIVE MAINTENANCE

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1 MAINTENANCE & LOGISTICS T.P.M TOTAL PRODUCTIVE MAINTENANCE Duval Pascal, Q.L.I.O Dept IUT of Béthune 1230, rue de l Université Béthune - France Abstract: After the ISO certification, it seems that we quickly get in the Total Productive Maintenance (TPM), another step in progress. The TPM is an organisational way of management that requires a change of behaviour and responsibilities. The TPM is, therefore, independent of the size of the company. What matters is the way setting, its management of setting and support. Therefore, the TPM can bring as much things to a small or medium-sized company that it would to a large company. It is necessary to take into account that TPM is an approach to land, and that each large company is cut out in intern SMC (Small and Medium Companies). To evaluate the factors of success or failures it would be better to interview directly companies that are using TPM. This report describes logically the principle of this procedure which is based on simple definitions and concepts. Key words: Total Productive Maintenance, Organization, Performance summary, Continuous improvement, Quality. 1. INTRODUCTION Total Productive Maintenance TPM is a maintenance concept for maintaining plants and equipment. The main goal of the TPM is to increase production while, at the same time, increasing employee morale and job satisfaction. With the Total Productive Maintenance concept, maintenance is no longer considered as a non-profit activity but as an important process of the overall business increase. Total Productive Maintenance aim is to reduce as much as possible activity stops due to maintenance. Basically, TPM is to equipments and machines what medicine is to human beings. The meaning of Total Productive Maintenance is: Maintenance: Maintain, keep in good operating condition = repair, clean, lubricate and grease, and accept to allocate all the necessary time. Productive: Do the maintenance job while producing or at least minimizing the impact on production. Total: Consider every aspect and involve everybody. History of TPM Evolution of the preventive maintenance concept (born in the USA), TPM is, once more with Lean Manufacturing related concepts, a Japanese concept. Japanese firms started to implement preventive maintenance in their plants around 1951.One of these companies, noticed a cost increased due to dedicated team for maintenance operations as the automation was developing in their plant. That company then decided that operators should do themselves all standard maintenance operations. This decision gave changed the preventive maintenance to productive maintenance where productive refers to the fact that production staff are doing the maintenance. The word Total was added to show that all plant staff should be involved to achieve better result. 19

2 2 - ANALYSE Losses (MUDA) and TPM The losses are defined by an excess of expenditures over revenues generated. Regarding TPM, losses are treated as unnecessary expenses (wasteful!). That affect the performance of the equipment itself, but also that of labor, materials and energy used. TPM aims to reduce and to eliminate 16 causes of losses to improve the performance of the production system : 1 - Eight losses related to equipment 1. losses due to outages, 2. losses due to adjustments, 3. losses due to change of tools 4. losses at startup 5. losses due to micro stops and dry run, 6. losses due to sub speed 7. losses due to defects and alterations, 8. losses due to outages and the closure of the workshop 2 - Five losses in labor 1. losses due to management, 2. losses due to the speed of execution 3. losses due to the organization of the line 4. losses due to logistics, 5. losses due to measures and adjustments 3 - Three losses in materials, machinery and equipment 1. losses due to energy 2. losses due to tooling, 3. losses due to performance of the material 3. METHOD TPM has five goals according JIPM (Japan Institute of Plant Maintenance) : 1. A clear business culture is designed to continuously improve the efficiency of the total production system 2. A standardized and systematic approach is used, where all losses are prevented and/or known. 3. All departments, influencing productivity, will be involved to move from a reactive- to a predictive mindset. 4. A transparent multidisciplinary organization is reaching zero losses. 5. Steps are taken as a journey, not as a quick menu. TPM identifies the different MUDA (types of waste) and then works systematically to eliminate them by making improvements (KAIZEN). TPM has 8 pillars of activity, each being set to achieve a zero target. (Fig. 1.) 20

3 BASEMENT - 5S Fig pillars of TPM PILLAR 1 - Autonomous maintenance PILLAR 2 - Equipment and process improvement (KAIZEN) PILLAR 3 Planned Maintenance PILLAR 4 - Quality Maintenance PILLAR 5 - Initial Flow Control PILLAR 6 Education and Training PILLAR 7 - TPM in Office (Support functions) PILLAR 8 Safety, health and Environment TPM is more than keeping machines in a good state, TPM fosters improvement. Operator involvement is an opportunity to raise their know-how level and enrich their jobs with basic maintenance tasks. Operator do know well the machines, they are living intelligent sensors, able to detect abnormal situation by unusual noise, odour, colour or vibrations... The performance indicator used in TPM is the Overall Equipment Efficiency, OEE. OEE give a simple and synthetic, yet severe overview, taking into account all parameters decreasing machine yield. OEE is building on three "themes": availability, performance and quality.the follow-up and analysis of OEE components indicates where to focus for improvement. 21

4 TPM is a mature method that got evens more interest with the end of mass production. It is harder to pay-off and make profit with high cost equipment and small size, customized productions. These high-tech machines require more and more highly skilled personnel. Empowered small teams ask for more autonomy and job enrichment. As operators are keys for overall shop performance, it is management duty to keep them motivated, skilled and autonomous. The breakthrough and progress achieved with TPM, its apparent simplicity made this method popular. BUT TPM deployment is not so simple! There are several pitfalls and as many other projects, TPM sometimes will not survive after the first public address and enthusiastic beginning. Main pitfalls in TPM are bad targeting of first pilot machines, data collection and operator so deeply involved in TPM activities they'll forget to produce! It is better to start TPM in a well targeted workshop, line or machine and extend it gradually to other areas. TPM came up when machine productivity was to be improved. Japanese engineers spend a lot of time on shop floor (the "Gemba", or "where it happens") watching and taking data. A MACHINE'S DAY No machine can run during total available shop time. There are necessities like changeovers, feedings, preheating or daily maintenance requesting the machine to stop, or at least suffer non productive time. Compared to shop opening time, the machine productive time is called Gross (or raw) machining time. In this gross machining time, one expects production achievements to be equal to time divided by standard pace or machine Takt (Takt = available time / number of units consumed or sold) Yet production data show results are much lower! Random disruptions cause performance to drop; failures, drifts, micro-stops... As a matter of fact, real Takt is always lower than standard Takt. Gross machining time minus lost time equals real or net machining time. Losses occur further on when we realize time used to produce parts was spent to produce good parts as well as defective ones... Some of the defective ones may be reworked, with additional expenses; others may just end as scrap. TPM Monitoring - Loss Measurement. The fig.2. above shows well all kind of losses causing machine productivity to drop. Choosing non accurate monitoring system may not reflect the real situation. To insure a good monitoring and drive improvement projects, a far more detailed system is requested. TPM proposes an all-in-one rate combining all machine productivity factors; OEE Overall Equipment Efficiency. OEE is also called "demonstrated capacity". 22

5 Let's see how to calculate OEE and what it components are: A = available time: workshop opening time or possible operating time. Available Time = shop opening B = gross machining time B = A - total of machine stops (failures, changeovers, feedings..) Gross machining Time Planed nonproductive actions C = net machining time C = B - performance loss = difference between theoretical and actual Takt due to minor stops Net machining Time During C good parts as well as defective are processed D = usable time => time producing good parts D = C - quality loss: non quality, settings, trials, starting... Usable time non quality With above definitions, we can define three rates: Fig. 2. OEE concept breakdown, performance loss Availability rate = B/A = Workshop opening time-stops / Workshop opening time Performance rate = C/B = net running rate x speed yield with: Net running rate = (quantity processed x cycle time) / (Workshop opening time - stops) And speed yield = theoretical cycle time / real cycle time Quality rate = D/C = (Total processed quantity - No good quantity) / total processed quantity Finally a super rate: Overall Equipment Efficiency, OEE. OEE = availability x performance x quality 4 - CONCLUSION ON TOTAL PRODUCTION MAINTENANCE - TPM Benefits of TPM Here are some of the most important benefits of Total productive maintenance: Reduce cost. Increasing productivity OPE and OEE, without reducing product quality. Avoid any kind of waste. Satisfy customers needs by 100 % Reduce accidents. Follow-up of environmental control measures. 23

6 Here are some of the secondary benefits of Total productive maintenance: Increase staff s confidence level Cleaner then more attractive work zones Team work development. Stronger implication of staff Strong personal relationship between workers and the equipment. Widen staff skills TPM has proved many times that it is a working concept, giving competitive results compared to the engaged resources. One key point will be sure of the involvement of all employees and to have a fully committed management. Moreover, TPM concept is highly adaptable to other activities than industrial ones like real estate, construction, logistics Machine theoretical performances are far from actual, daily measured achievements. A lot of disturbing factors cause the performance to drop. Simple follow-up, like "machine work time/shop open time" ratio might therefore be misleading. OEE give a complete, yet synthetic, all encompassing view of the machine efficiency. Further analysis on OEE components highlight where improvement efforts must be focused. TPM does not interfere with "classic" maintenance on fundamentals, but proposes to empower the people in steady contact with machines to take over a part of the job. For them, it is an opportunity to enrich their routine. Well done, TPM improves machine yield, favors team spirit and value operator's contribution to value creation. TPM is a good opportunity to raise operator's skills and know-how, to foster improvement suggestions. TPM should be started in a pilot process or workshop and later extended. Beware not to turn actors into "accountants" as data capture for OEE requires often a huge effort! Don't forget production is about sellable goods, not data! 5. REFERENCES [1]. La Maintenance Productive Totale (TPM) Nouvelle vague de la production industrielle SEIICHI NAKAJIMA, afnor gestion, 1987 [2]. - Maintenance Méthodes et organisations François Monchy, DUNOD, 2 e édition [3]. - Le guide TPM de l unité de travail Conduite et maintenance de l installation industrielle -Kunio Shirose- Traduit de l'américain par Monique Sperry -Edition DUNOD [4]. Le zéro-panne par la topomaintenance : la TPM à la française / C. Barbier, R. Dapère, C. Huber.- Maxima.- [Paris] : diffusion Presses universitaires de France, c1993. [5]. Websites: 1. La lettre du centre des technologies nouvelles : 2. This site contains information on several items (quality, TPM, management, organization.) 24