Your Reliability Engineering Professional Development Site
A listing in reverse chronological order of articles by:
The t-test was first described by William Sealy Gosset in 1908, when he published his article under the pseudonym ‘student’ while working for a brewery. Gosset, an Englishman, developed the t-test and t distribution, and he is considered the “godfather” of the t-test.
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Preventive maintenance is a proactive approach used by industries to ensure the longevity and optimal performance of their assets. It involves regular maintenance tasks such as cleaning, lubrication, parts replacement, and equipment repairs to prevent unplanned downtime.
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HALT (Highly Accelerated Life Testing) is the foundation for the definition of HASS (Highly Accelerated Stress Screening) and HASA (Highly Accelerated Stress Audit).
HALT is primarily used to expose weaknesses in the design of a product by subjecting it to extreme environmental conditions such as temperature, vibration, and humidity, in order to identify and eliminate design flaws and weak points before the product is released to the market.
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Understanding the different types of data and thier respective uses is critical for product delveopment testing and analysis.
Each type of eo f data plays a a role in ensuring that products meet quality standards and fulfill user needs.
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Accelerated Life Testing (ALT) on subcomponents and durability testing for whole products are two strategies used to assess the reliability of products. ALT involves subjecting a product to conditions beyond its normal service parameters to uncover faults and potential failure modes in a short time, allowing engineers to make predictions about its service life and maintenance intervals. On the other hand, durability testing for whole products involves testing the entire product under normal operating conditions to assess its long-term reliability and performance.
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Using highly accelerated stress screening to identify supplier defects before the product is shipped saves time and money.
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The history of Design of Experiments (DOE) can be traced back to the work of various individuals, including Genichi Taguchi, a Japanese engineer and statistician. Taguchi made significant contributions to the field, particularly in the area of robust design, which aimed to improve the quality of products and processes. His work was influenced by the need for quality improvement in post-World War II Japan. Taguchi’s methodology, known as the Taguchi methods, was based on the concept of “robust parameter design,” which aimed to make processes and products insensitive to environmental factors or other variables that were difficult to control.
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Because the people that make them lie.
Not ‘obvious’ lying where lightbulb manufacturers calculate one reliability number and deliberately choose to put another number on their lightbulb packaging. But ‘insidious’ lying where they deliberately choose to measure the wrong thing to get a better number.
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Designing a proper test for the life of an electromechanical compoent involves several steps and considerations. Here are six steps that provides an outline to create a meaningful component life test.
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A one-sample t-test is a statistical test to determine if the sample mean differs significantly from a known or hypothesized population mean (expected value). It is commonly used when we have a single sample and want to compare its average to an expected value.
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Accelerated life testing (ALT) is a method used to enhance product reliability by subjecting prototypes to stress levels significantly higher than those encountered in actual use.
By increasing the stress on the component, failure is induced more rapidly, which is equivalent to speeding up the passage of time. This approach is particularly useful when waiting for failures to occur at their normal rate is not feasible, such as when a manufacturer needs to release a product to the market soon and cannot afford to spend several years performing a reliability test.
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A short video defining accelerated life testing or ALT.
An introduction to ALT or accelerated life testing. ALT is a method used to enhance product reliability by subjecting prototypes to stress levels significantly higher than those encountered in actual use. In short, it’s a way to accelerate time.
[Read more…]Some history:
The executives of the Powertrain Organization (transmissions, chassis, engines) wanted a methodology where teams (design engineering, manufacturing engineering, and production) could work on recurring chronic problems. In 1986, the assignment was given to develop a manual and a subsequent course that would achieve a new approach to solving identified engineering design and manufacturing problems.
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A short video discussing the importance to engineering test data analysis of confidence intervals.
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