The object of production improvement activities is to increase productivity by minimizing input and maximizing output. More than sheer quantity, “output” includes improving quality, reducing costs, and meeting delivery dates while increasing morale and improving safety and health conditions, and the working environment in general.
The relationship between input and output in production activities can be illustrated in a matrix (in Fig. 2). Input consists of labor, machines, and materials, while output is composed of production (P), quality (Q), cost (C), delivery (D), safety, health and environment (S), and morale (M).
Correlating these factors in terms of equipment maintenance demonstrates clearly that all aspects of PQCDSM are related to output. With increasing robotization and automation, the more the production process shifts from workers to machines, the larger the role played by the equipment itself in controlling output, or PQCDSM. Productivity, quality, cost, and delivery, as well as safety and health, environment, and morale all depend on the condition of equipment. TPM strives to maximize output (PQCDSM) by maintaining ideal operating conditions and running equipment effectively. A piece of equipment that suffers breakdown experiences periodic speed losses, or lacks precision and produces defects are not operating effectively. The life cycle cost (LCC) (the cost incurred during the equipment’s life span) required maintaining equipment at its optimal level is limited. TPM strives to achieve overall equipment effectiveness by maximizing output while minimizing input, i.e. LCC.
To achieve overall equipment effectiveness, TPM works to eliminate the “six big losses” that are formidable obstacles to equipment effectiveness. They are as follows:
EQUIPMENT EFFECTIVENESS IS A MEASURE OF THE VALUE ADDED TO THE PRODUCTION THROUGH EQUIPMENT
TPM MAXIMISES EQUIPMENT EFFECTIVENESS THROUGH TWO TYPES OF ACTIVITY:
QUANTITATIVE: INCREASES TOTAL AVAILABILITY OF EQUIPMENT AND ITS PRODUCTIVITY WITHIN A GIVEN PERIOD OF OPERATING TIME
QUALITATIVE: REDUCING NUMBER OF DEFECTIVE PRODIUCTS AND STABILIZING AND IMPROVEMENT QUALITY.
* Number of good products = Input – (start up defects–process defects–trial products)
Overall Equipment Effectiveness = Availability x Performance Rate x Quality Rate
Various factors influencing availability and their interdependencies are given in Figure - 3
STABILISE EQUIPMENT FAILURE INTERVALS (MTBF)
LENGTHEN EQUIPMENT LIFE
PERIODICALLY RESTORE DETERIORATION
PREDICT EQUIPMENT LIFE