What is Total Productive Maintenance?

 

The modern view of maintenance is that it is all about preserving the functions of physical assets. In other words, carrying out tasks that serve the central purpose of ensuring that our machines are capable of doing what the users want them to do, when they want them to do it. The possible maintenance policies can be grouped under four headings viz.

1. Corrective - wait until a failure occurs and then remedy the situation (restoring the asset to productive capability) as quickly as possible.

2. Preventive - believe that a regular maintenance attention will keep an otherwise troublesome failure mode at bay.

3. Predictive - rather than looking at a calendar and assessing what attention the equipment needs, we should examine the 'vital signs' and infer what the equipment is trying to tell us. The term 'Condition Monitoring' has come to mean using a piece of technology (most often a vibration analyser) to assess the health of our plant and equipment.

4. Detective - applies to the types of devices that only need to work when required and do not tell us when they are in the failed state e.g. a fire alarm or smoke detector. They generally require a periodic functional check to ascertain that they are still working.

Apart from detective maintenance, the central problem that companies have struggled with is how to make the choice between the other three. This has led to the increasing interest within industry in two strategies, which offer a path to long term continuous improvement rather than the promise of a quick fix. These are Reliability Centred Maintenance (RCM) and Total Productive Maintenance (TPM). The two strategies, although having similar names, actually have very different strengths. RCM has been fully described while TPM will now be discussed.

TPM is a manufacturing led initiative that emphasises the importance of people, a 'can do' and 'continuous improvement' philosophy and the importance of production and maintenance staff working together. It is presented as a key part of an overall manufacturing philosophy. In essence, TPM seeks to reshape the organisation to liberate its own potential.

The modern business world is a rapidly changing environment, so the last thing a company needs if it is to compete in the global marketplace is to get in its own way because of the way in which it approaches the business of looking after its income generating physical assets. So, TPM is concerned with the fundamental rethink of business processes to achieve improvements in cost, quality, speed etc. It encourages radical changes, such as;

  •  flatter organisational structures - fewer managers, empowered teams,

  •  multi-skilled workforce,

  •  rigorous reappraisal of the way things are done - often with the goal of simplification.

It also places these changes within a culture of betterment underpinned by continuous improvement monitored through the use of appropriate measurement. The principal measure is known as the Overall Equipment Effectiveness (OEE). This figure ties the 'six big losses' :

1. Equipment Downtime
2. Engineering Adjustment
3. Minor Stoppages
4. Unplanned Breaks
5. Time spent making reject product
6. Waste

to three measurables:

Availability (Time), Performance (Speed) & Yield (Quality).

When the losses from Time X Speed X Quality are multiplied together, the resulting OEE figure shows the performance of any equipment or product line.

TPM sites are encouraged to both set goals for OEE and measure deviations from these. Problem solving groups then seek to eliminate difficulties and enhance performance.

TPM achievements

Many TPM sites have made excellent progress in a number of areas. These include:

  •  better understanding of the performance of their equipment (what they are achieving in OEE terms and what the reasons are for non-achievement),

  •  better understanding of equipment criticality and where it is worth deploying improvement effort and potential benefits,

  •  improved teamwork and a less adversarial approach between Production and Maintenance,

  •  improved procedures for changeovers and set-ups, carrying out frequent maintenance tasks, better training of operators and maintainers, which all lead to reduced costs and better service,

  •  general increased enthusiasm from involvement of the workforce.

    However the central paradox of the whole TPM Process is that, given that TPM is supposed to be about doing better maintenance, why do proponents end up with (largely) the same discredited schedules that they had already (albeit now being done by different people)? This is the central paradox - yes, the organisation is more empowered, and re-shaped to allow us to carry out maintenance in the modern arena, but we're still left with the problem of what maintenance should be done.

    The RCM process was evolved within the civil aviation industry to fulfil this precise need. In fact, the definition of RCM is "a process used to determine the maintenance requirements of physical assets in their present operating context". In essence, we have two objectives; determine the maintenance requirements of the physical assets within their current operating context, and then ensure that these requirements are met as cheaply and effectively as possible.

    RCM is better at delivering objective one; TPM focuses on objective two.

Can the techniques be deployed together?

The answer depends on what 'brand' of RCM is being considered. The 'hired gun' or 'magic box' approach will never be compatible with TPM. RCM must be performed by the organisation itself. The sole focus must be to teach organisations to analyse their own assets. In this way, empowered teams remain empowered, ownership is retained and enhanced and companies begin to win the asset management battle.

Your company can also benefit from TPM. Our 2 day TPM seminar will show you exactly how.

See what others have to say about our training seminars here.

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