Measuring Reliability

Measuring Reliability

Equipment reliability is a critical consideration in a manufacturing environment. When implementing a lean manufacturing Six Sigma program, this becomes a particularly pertinent area of examination, as it can be a source of waste. Establishing a current reliability benchmark and quantifying the effects of process changes requires an accurate assessment of equipment reliability. It is critical, therefore, that the system of metrics used has the correct focus.

The general consensus regarding reliability is that it is intrinsically tied to maintenance practices and personnel alone. In fact, however, operations and production practices have a considerable effect upon equipment condition and performance. Plans for measurement and improvement, then, require that both maintenance and operations be charged with the responsibility of equipment reliability.

Gathering reliability data

Several sources should be consulted to gather accurate reliability data. This is particularly important to the success of lean manufacturing Six Sigma implementation in that a more accurate picture of performance may be constructed. Measuring reliability is not a matter of counting output alone. Several factors, in actuality, contribute to overall reliability. Capacity data may be obtained from operations records or manufacturing control systems. Inventory control and purchasing systems are valuable sources of information regarding parts and material use. Furthermore, accounting, quality and human resource systems should also be consulted. Each can provide illuminating data on equipment performance, operator interaction, and production conditions, all of which play a role in reliability.

Considerations in measuring reliability

To gather relevant data that provides an accurate picture of reliability, there are several considerations to keep in mind. A lean Six Sigma for manufacturing plan requires the establishment of benchmark measures before processes can be redefined with greater efficiency. Reliability measurement targets should next be determined.

When measuring reliability, it is important that the data provide a full and accurate picture of current conditions. The following activities should be included in this effort:

  • Cost data for labor, parts, maintenance and materials should be culled.
  • Factor in issues such as time, speed, scrap and quality losses.
  • Note causes of losses, such as faulty design, operation or maintenance practices.
  • Determine what departments have an impact upon downtime and to what extent.
  • Compare an organization’s available resources (manpower, materials, production location, etc.) against the current workload.
  • Quantify the severity of a work backlog (the amount of work requested or scheduled compared to delays caused by emergency or routine maintenance activities or equipment failures).