The Difference Between Quality and Reliability
Abstract
Adam and Fred discussing the difference between Quality and Reliability.
Key Points
Join Adam and Fred as they discuss the difference between Quality and Reliability.
Topics include:
- Can Quality and Reliability both be under the same leadership in an organization?
- Are both a part of the product development process and manufacturing process equally?
- Is Reliability everything Quality is over time or is Reliability only one aspect of Quality?
Enjoy an episode of Speaking of Reliability. Where you can join friends as they discuss reliability topics. Join us as we discuss topics ranging from design for reliability techniques, to field data analysis approaches.
SOR 121 The Difference Between Quality and ReliabilityAdam Bahret
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Show Notes
RELIABILITY IS QUALITY OVER TIME:
The term “quality of a product” is loosely taken to mean its inherent degree of excellence. In industry, this is made more precise by defining quality to be “conformance to requirements at the start of use”. Assuming the product specifications adequately capture customer requirements, the quality level can be measured by the fraction of units shipped that meet specifications.
But how many of these units still meet specifications after a week of operation? Or after a month, or at the end of a one year warranty period? That is where “reliability” comes in. Quality is a snapshot at the start of life and reliability is a motion picture of the day-by-day operation. Time zero defects are manufacturing mistakes that escaped final test. The additional defects that appear over time are “reliability defects” or reliability fallout.
The quality level can be described by a single fraction defective. To describe reliability fallout a probability model that describes the fraction fallout over time is needed. This is known as the life distribution model.