Reliability engineering is engineering that emphasizes dependability in the lifecycle management of a product. Dependability, or reliability, describes the ability of a system or component to function under stated conditions for a specified period of time. Reliability engineering represents a sub-discipline within systems engineering. Reliability is theoretically defined as the probability of success (Reliability=1-Probability of Failure), as the frequency of failures, or in terms of availability, as a probability derived from reliability and maintainability. Maintainability and maintenance is often defined as a part of “reliability engineering” in Reliability Programs. Reliability plays a key role in the cost-effectiveness of systems.
Reliability engineering deals with the estimation and management of high levels of “lifetime” engineering uncertainty and risks of failure. Although stochastic parameters define and affect reliability, according to some expert authors on Reliability Engineering, e.g. P. O’Conner, J. Moubray and A. Barnard, reliability is not (solely) achieved by mathematics and statistics. “Nearly all teaching and literature on the subject emphasize these aspects, and ignore the reality that the ranges of uncertainty involved largely invalidate quantitative methods for prediction and measurement”
Reliability engineering relates closely to safety engineering and to system safety, in that they use common methods for their analysis and may require input from each other. Reliability engineering focuses on costs of failure caused by system downtime, cost of spares, repair equipment, personnel and cost of warranty claims. Safety engineering normally emphasizes not cost, but preserving life and nature, and therefore deals only with particular dangerous system-failure modes. High reliability (safety factor) levels also result from good engineering, from attention to detail and almost never from only re-active failure management (reliability accounting / statistics).
Reliability engineering or the work to minimize failures, improve maintenance effectiveness, shorten repair times, and meet customer & organization expectations has many benefits. Here is a list of benefits to consider when wondering if your work as a reliability professional is worth the effort.
- Expectation – Products work under environmental and use conditions imposed by the customer. Creating a product the matches the expectations imposed by the customer permit the product to work as expected. Understanding the conditions allow the design to meet without over designing thus optimizing product cost and customer satisfaction.
- Time – Unanticipated failures cost time for customers and for the organization to resolve the failures. Using reliability and availability concepts we can minimize failures and avoid wasting time.
- Throughput – Downtime for any reason reduces the system’s throughput, downtime can be minimized by applying predictive and preventative maintenance programs. A well maintained system minimizes operating expenses and maximizes throughput.
- Production – Some products require a run-in or burn-in to identify and eliminate early life failures or to refine and optimize system operation. Using reliability engineering techniques we can minimize the time and resource impact of run-in or burn-in operations. Eliminating or minimizing the time we reduce inventory carrying costs, tooling costs, and energy requirements.
- Distribution – Fewer failures and optimized maintenance implies fewer spare parts in the logistics system. This minimizes the distribution system costs for transportation, logistics, and storage for spare parts. This also minimizes service labor costs.
- Warranty – Products that operate as expected without failure avoid being returned or serviced under warranty. Calls to service support, trouble shooting, product returns, failure analysis, and reengineering all part of the cost of unreliability. Warranty provides customers insurance in case of failure and with reliability engineering techniques the costs are minimized.
- Safety – Some product failure cause unintended or unsafe conditions leading to loss of life or injury. Reliability engineering tools assist in identifying and minimizing safety risks.
- Liability – Product failures can cause the loss of property. Minimizing failures and mitigating the damage caused by any failure minimizes the exposure to liability for the property loss.
- Design – Enhancing the design team’s reliability engineering capabilities through training and staffing of reliability professionals enables the entire team to make decisions fully considering the impact on product reliability. This reduces the need for expensive redesign or rework costs to address reliability related design errors.
There are more ways reliability engineering is of value, yet this list provides a few ways to consider the benefits of reliability engineering. Optimizing reliability has plenty of benefits, therefore enjoy the difference you are making.
