Modelo de factores críticos de éxito para proyectos de implementación

The next step is defining daily maintenance that workers should carry out them-selves. Workers are often only trained for production, and maintenance, be it simple or complex, is left to be carried out by trained professionals. This happened in many companies before TPM principles were introduced; workers were trained for production leaving all the other aspects to specialists. Assigning maintenance to external operators often leads to the following consequences:

• Loss of information that can only be registered by workers that use a certain machine on a daily basis. We offer the following example: in a manufacturing company a worker noticed strange vibrations that led, a couple of days later, to a massive breakdown. The worker had been trained to produce as much as possible, without wasting time with reports or warning, leaving maintenance to other members of staff.

• Loss of awareness regarding the fact that the quality of the product also depends on the quality of the machine.

• Increase in machine management costs.

• Reduction of machine life expectancy.

Workers require specific training if they are to simultaneously produce, check performance and product quality, and carry out maintenance. Companies that apply TPM recommend training based on:

• 5S;

• Basic technical knowledge of the machine;

• Basic maintenance, lubrication, cleaning, adjustments, check-ups, and so on;

• How to predict breakdowns;

• Knowledge on defining the cause of a breakdown;

• Knowledge on common causes of breakdown or decrease in quality;

• Basic process knowledge and information regarding what can cause defects in products;

• Knowledge regarding how to interpret altered machine functioning;

• How to identify the cause of defects and how to deal with said causes;

• How to react in case of emergency;

• How to replace and repair machine components;

• Safety measures.

To help workers adjust to new procedures, checklists containing instructions on how to carry out operations can be drawn up.

6.9.3 Preventive Maintenance

Workers who have been suitably trained can carry out daily maintenance procedures. These procedures are thus included in daily production activities and

are no longer considered additional services that waste production time. By cleaning, lubricating, adjusting, carrying out small maintenance operations and keeping tabs on quality and performance, OEE levels dramatically increase in short periods of time. Thus efficiency and productivity increase, and general defectiveness decreases. The worker will, however, have limited knowledge regarding certain functions and technical details because these are increasingly linked to complex software and structures: complicated or specific maintenance will have to be carried by a specialized professional.

Once daily maintenance has been ensured, the next problem is programming maintenance that has to be carried out periodically over longer periods of time.

Maintenance that has to be carried out once a month, every 2 months or every half-year has to be planned in advance. Preventive maintenance needs to be viewed as a necessary measure to avoid breakdowns, machine failures or loss of quality that could cause great damage. Often machines break down due to lack of maintenance, causing major hold-ups in production; even small losses of speed can be avoided through regular maintenance.

The main problem is calculating how often these maintenance operations should be carried out to avoid problems. Specific software and files need to be kept up-to-date with all maintenance carried out, acting as a reminder for the next appointments. This database should initially refer to recommendations listed in manuals; however, over longer periods of time, unexpected problems requiring immediate attention could crop up. Workers should carry out daily maintenance and check-ups, reporting any anomalies or problems they notice and, if necessary, modifying the maintenance plan. Figure6.24shows a typical worksheet recording maintenance carried out and any problems registered. The area is checked and maintained according to a checklist; any problem or unexpected operation has to be recorded. These sheets can be used, according to the type of machine, for periods of time varying from 1 week to a month; the team will have to deal with unexpected problems when they crop up.

These reports, recorded in the database, help workers understand whether the frequency of certain operations needs to improve, or whether new maintenance programs need to be introduced. The problem described on the spreadsheet regards vibrations caused by the recirculation screws; if this problem should cause a breakdown every 14 months, for example, a specific maintenance operation should be carried out at least once a year. Maintenance databases use the following indicators to analyze problems:

Mean Time Between FailuresðMTBFÞ ¼ Mean Time To Failure ðMTTFÞ þ Mean Time To Repair ðMTTRÞ MTTF is applied to systems that cannot be repaired, measuring the time leading up to the failure of the system, which then needs to be replaced. Most screws have several tens of thousands of hours of MTTF; they are then replaced because they cannot be repaired. MTBF is applied to systems that can be repaired; it is the total of MTTF (calculated regarding the component that requires reparation) and the

114 6 The Main Methods of Lean Organization

average time necessary for the repair. For example: a mold has MTTF of 260 days and an average repair time of around 15 days, altogether 275 days.

Bibliography

Alukal, G., Manos A.: Lean Kaizen: A Simplified Approach to Process Improvements, p. 900.

ASQ, Milwaukee (2008)

Arai, K., Sekine, K.: TPM for the Lean Factory: Innovative Methods and Worksheets for Equipment Management. Productivity Press, Portland (1998)

Machine maintenance sheet

Machine: MP IT 2 Month: June Check list: WI-18

Machine problems/failures – Unexpected maintenance

# Date/time Problem Signature State

1 5/6- 8:23 Vibration on

screw (X -axis)

Paul N

2 14/6-5.00 Docking tool

post. It doesn’t release it

Paul IM –

A45

3 15/6-8:41 Vibration on

X-axis screw (see note)

John R

Explanation:

N = New. Observed for the first time R = Repetitive (it needs analysis) IM = Immediate Maintenance

PM = Postponed Maintenance (Operator not able to) Note:

3 – In my opinion you can perceive vibrations just during the first work-hour

Fig. 6.24 Sheet recording problems and unexpected maintenance

Ballakur, A., Steudel, H.J.: A within-cell utilization based heuristic for designing cellular manufacturing systems. Int. J. Prod. Res. 25, 639–665 (1987)

Ham, I., Hitomi, K., Yoshida, T.: Group Technology: Applications to Production Management.

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Imai, M.: Gemba Kaizen: A Commonsense Low-Cost Approach to Management. McGraw Hill, New York (1997)

Junewick, M.A.: Lean Speak: The Productivity Business Improvement Dictionary. Productivity Press, New York (2002)

Khanna, V.K., Vrat, P., Shankar, R., Sahay, B.S.: Usage of quality tools in the Indian automobile sector. J. Manage. Res. 3, 157–169 (2006)

Kusiak, A.: The generalized group technology concept. Int. J. Prod. Res. 25, 561–569 (1987) Liker, J.K.: The Toyota Way, 14 Management Principles from the World’s Greatest Manufacturer.

McGraw-Hill, New York (2004)

Monden, Y.: Toyota Production System: An Integrated Approach to Just-in-Time. Industrial Engineering & Management Press, Norcross (1993)

Ohno, T.: Toyota Production System Beyond Large-Scale Production. Productivity Press, Cambridge, MA (1988)

Sekine, K.: One-Piece Flow: Cell Design for Transforming the Production Process. Productivity Press, Cambridge, MA (1992)

Shingo, S., Dillon, A.P.: A Revolution in Manufacturing: The SMED System. Productivity Press, Stamford (1985)

Tapping, D.: The Lean Pocket Guide: Tools for the Elimination of Waste. MCS Media Inc – Technology & Engineering, Chelsea (2002)

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Mag. 16, 347–353 (2004)

116 6 The Main Methods of Lean Organization

Lean Metric, Lean Accounting and Value Stream Accounting

Everything that can be counted does not necessarily count;

everything that counts cannot necessarily be counted A. Einstein

7.1 Introduction

Chapter4, which mainly focused on Hoshin Kanri strategic planning, discussed the importance of defining strategic goals that can be deployed to measurable annual targets when striving to apply Lean. The indicators and targets of these goals control Kaizen workshops and other improvement program results directly through Key Performance Indicators (KPIs). Specific Lean KPIs fall into the Lean Metric category and will be explained in further detail in the following sections. Several of these indicators are also used by TQM systems and are known as cost of quality;

others are specific to Lean application, such asOverall Equipment Effectiveness (OEE). Each company should carefully evaluate its strategic goals to be able to decide which process indicators are best suited, according to the deployment process explained in Chap, 4. Organizations of business excellence that have already applied Lean recommend that indicators should be shared, easy to measure and, in particular, measurable in real-time. One of the main principles that Lean is based on is, in fact:

Solve problems when they occur without postponing them.

To be able to resolve problems when they occur means having access to key indicators every single day, without having to wait for monthly reports. Many authors and companies that have successfully applied Lean claim that Lean means speed; thus it is vitally important to have day-by-day or, even better, day-by-the-hour process data updates. Many organizations make use of expensive ERPs or similar management systems that produce interesting and detailed monthly reports. However, for many types of analysis one month is nothing short of forever and customers do not like having to wait that amount of time. If the process or cell

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DOI 10.1007/978-88-470-2510-3_7,# Springer-Verlag Italia 2013

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does not abide to takt-time or if it produces defects, then changes have to be made as soon as possible. If no automatic monitoring systems are available, then flipcharts and whiteboards can provide good solutions: in this case the amount of products, defects and problems occurred should be recorded every hour or at the end of each shift. Analyzing these results can lead to discussions regarding the efficiency of traditional analytic accounting systems.

The system should in any case highlight, even approximately, the economic benefits obtained. Problems linked to correctly charging overhead costs and calculations based on the hours of manual labor can lead to aberrations and distortions.