Total productive maintenance (TPM)

Total productive maintenance (TPM) is the systematic execution of maintenance by all employees through small group activities.

The dual goals of TPM are zero breakdowns and zero defects; this obviously improves equipment efficiency rates and reduces costs. It also minimises inventory costs associated with spare parts.

It is claimed that most companies can realise a 15%-25% increase in equipment operation rates within three years of adopting TPM. Labour productivity also generally increases by a significant margin, sometimes as high as 40%-50%.

The Japanese imported preventive maintenance (PM) from the United States in the 1950s and it remained well established until the 1970s. This consisted mainly of time-based maintenance featuring periodic servicing and overhaul. During the 1980s PM was steadily replaced by predictive maintenance, or condition-based maintenance (see Reliability-Centred Maintenance). TPM is often defined as productive maintenance involving total participation; a kind of marriage between PM and TQM. Many organisations misconstrue this to imply that only shop floor staff need be involved. However, TPM should be implemented on a company-wide basis.

TPM aims to establish good maintenance practice through the pursuit of “the five goals of TPM”:

1. Improve equipment effectiveness: Examine the effectiveness of facilities by identifying and examining all losses which occur – downtime losses, speed losses and defect losses.
2. Achieve autonomous maintenance: Allow the people who operate equipment to take responsibility for at least some of the maintenance tasks. This can be at:
   1. the repair level (where staff carry out instructions as a response to a problem)
   2. the prevention level (where staff take pro-active action to prevent foreseen problems)
   3. improvement level (where staff not only take corrective action but also propose improvements to prevent recurrence).
3. Plan maintenance: Have a systematic approach to all maintenance activities. This involves the identification of the nature and level of preventive maintenance required for each piece of equipment, the creation of standards for condition based maintenance, and the setting of respective responsibilities for operating and maintenance staff. The respective roles of operating and maintenance staff are seen as being distinct. Maintenance staff are seen as developing preventive actions and general breakdown services, whereas operating staff take on the ownership of the facilities and their general care. Maintenance staff typically move to a more facilitating and supporting role where they are responsible for the training of operators, problem diagnosis, and devising and assessing maintenance practice.
4. Train all staff in relevant maintenance skills: The defined responsibilities of operating and maintenance staff require that each has all the necessary skills to carry out these roles. TPM places a heavy emphasis on appropriate and continuous training.
5. Achieve early equipment management: The aim is to move towards zero maintenance through Mmaintenance Prevention (MP). MP involves considering failure causes and the maintainability of equipment during its design stage, its manufacture, its installation, and its commissioning. As part of the overall process, TPM attempts to track all potential maintenance problems back to their root cause so that they can be eliminated at the earliest point in the overall design, manufacture and deployment process.

TPM works to eliminate losses:

• Downtime from breakdown and changeover times
• Speed losses (when equipment fails to operate at its optimum speed)
• Idling and minor stoppages due to the abnormal operation of sensors, blockage of work on chutes, etc.
• Process defects due to scrap and quality defects to be repaired
• Reduced yield in the period from machine start-up to stable production.

See Nakajima, S. (1988). Introduction to Total Productive Maintenance. Cambridge, MA: Productivity Press