TPM revitalises and enhances the quality management approach to improve capacity while reducing not only maintenance costs but overall operational costs. Its implementation has also resulted in the creation of safer and more environmentally sound workplaces.
TPM emphasizes the following facets:
i) Recognition of importance and total commitment to the program by upper level management is required, and
ii) Employees must be empowered to initiate corrective action
TPM brings maintenance into focus as a necessary and an integral part of the manufacturing process. Maintenance is no longer regarded as a non-profit activity. Down time for maintenance is scheduled as a part of the manufacturing day; it is no longer simply squeezed in whenever there is a break in material flow. The goal is to hold emergency and unscheduled maintenance to a minimum [485].
Equipment supplier’s maintenance schedules are reviewed by operators. The plant crew – machine operators – are additionally trained in the maintenance program and collaborates more closely with the maintenance personnel.
TPM is a manufacturing led initiative that emphasises the importance of people, production and maintenance staff working together, a ‘can do’ and ‘continuous improvement’ philosophy implementation. It is presented as a key part of an overall manufacturing philosophy. As an example, in one manufacturing plant, one punch press was selected as a problem area. The machine was studied and evaluated in extreme detail by the team. Production over an extended period of time was used to establish a record of productive time versus nonproductive time. Some team members visited another plant which operated a similar press much more efficiently. A course of action to bring the machine into a “world class” manufacturing condition was soon designed. This involved taking the machine out of service for cleaning, painting, adjustment, and replacement of worn parts, belts, hoses, etc. As a part of this process, training in operation and maintenance of the machine was reviewed. A daily check list of maintenance duties to be performed by the operator was developed. A factory representative was called in to assist in some phases of the process.
After success has been demonstrated on one machine improved production, another machine was selected, then another, until the entire production area had been brought into a “world class” condition with significantly higher production rates.
Note that in the example above, the operator was required to take an active part in the maintenance of the machine. This is one of the basic innovations of TPM. Routine daily maintenance checks, minor adjustments, lubrication, and minor part change out become the responsibility of the operator. Extensive overhauls and major breakdowns are handled by plant maintenance personnel with the operator assisting. Even if outside maintenance or factory experts have to be called in, the equipment operator must play a significant part in the repair process.
TPM 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 norms:
Availability (Time), Performance (Speed) & Yield (Quality).
When the losses from Time, Speed and 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.
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 [486].
Ford, Eastman Kodak, Motorola, Boeing, Dupoint; these are just a few of the companies that have implemented TPM successfully. All report an increase in productivity using TPM. Kodak reported that a $5 million investment resulted in a $16 million increase in profits which could be traced and directly to implementing a TPM program. One appliance manufacturer reported the time required for die changes on a forming press went from several hours down to twenty minutes! This is the same as having two or three additional million dollar machines available for use on a daily basis without having to buy them. Texas Instruments reported increased production figures of up to 80% in some areas. Almost all the above named companies reported 50% or greater reduction in down time, reduced spare parts inventory, and increased on-time deliveries. The need for out-sourcing part or all of a product line was greatly reduced in many cases.
Many companies who recognise the important roll equipment and process performance have on bottom-line results are turning to the measure which drives TPM called Overall Equipment Effectiveness (OEE) which incorporates not only Availability but also Performance Rate and Quality Rate. In other words, OEE addresses all losses caused by the equipment: not being available when needed due to breakdowns or set-up and adjustment losses; not running at the optimum rate due to reduced speed or idling and minor stoppage losses; and not producing first pass A1 quality output due to defects and rework or start-up losses. A key objective of TPM is to cost effectively maximise Overall Equipment Effectiveness through the elimination or minimisation of all losses. A simple model outlining these losses is shown below .
When organisations measure Overall Equipment Effectiveness (before implementing TPM) it is not uncommon to find they are only achieving around 40% - 60% (batch) or 50% - 75% (continuous process) whereas the international best practice figure is recognised to be +85% (batch) and +95% (continuous process) for Overall Equipment Effectiveness. In effect, this means there exists in most companies the opportunity to increase capacity / productivity by 25% - 100%.
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