Two of the most common acronyms used regarding manufacturing screening processes are ESS and HASS.
ESS stands for “Environmental Stress Screening” and HASS stands for “Highly Accelerated Stress Screening.” [Read more…]
ESS and HASS
Human Factors and Risk
Guest Post by Paul Kostek (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
There is an aviation old joke that in the future the airplane will have a crew of two, a pilot and a dog. The pilot to feed the dog and the dog to bite the pilot if he tries to touch anything.
I started this article after reading about United Airlines plan to bring in all 12,000 of its pilots for additional training outside of their normal training schedule. This was being done as a result of several incidents that raised concerns about pilot response to failures. [Read more…]
The Connection Between Nut Torque and Bolt Tension
(Why threads strip and bolts break)
When a bolt and nut is tightened to draw the bolt head and nut together it stretches the shank, deforms the threads and loads the object trapped between the bolt head and nut.
The bolt shank acts like a spring being pulled apart and it tries to return to its unloaded condition.
The amount of tension developed in the shank is dependent on the number of turns of the nut.
The size of the torque required to turn the nut has little to do with the tension applied to the bolt shank.
Rather the amount of torque needed to turn the nut reflects the slipperiness of the threads.
Keywords: bolt tension, yield stress, the coefficient of friction.
Introduction to High-Temperature Life Testing
A common reliability test involves ‘baking’ a few units.
Various standards list temperature, duration, and sample size requirements.
When the units survive the test, meaning there are no failures, what does that mean?
How do you interpret a system or component life test using high temperature?
Do the results suggest your product is reliable? Maybe it is maybe it isn’t.
Let’s examine one way to design and interpret high-temperature testing. [Read more…]
Reliability Questions to Ask Your Suppliers
Here’s a question for you: Do you ask your suppliers the right questions concerning reliability?
Probably not.
If you are getting the right information from your suppliers, then you would enjoy few supplier related field issues, or as little downtime or low warranty costs.
Asking the right set of questions will help you gain the understanding you need to improve your reliability performance. [Read more…]
The Side Swipe (part 2): A Surge in Technology Growth
It’s no longer an option to be the strong household name brand in an industry.
You have to expand your technology capabilities to stay in the market.
There are product lines that have had a consistent core technology for long periods of time.
Companies that are leaders in these are “the experts” and they hold maximum market share because the customers know what brand to buy if they want the best.
But if there is a sudden change in the technology, then that “bulletproof” brand name can be tarnished in one product cycle.
What if the core technology suddenly changes to include new electronics or software controls or something we would never have imagined.
The competitors are about to gain market share based on feature add, sometimes “jumped into the future” feature add; The iPad, Tesla electric vehicles, Tesla assisted autonomous driving, smartphone, Solid State memory, automotive electronic fuel injection, jet engines, desktop printer – this is a “Side Swipe”. [Read more…]
Common Sense Essentials to Great Design
Guest Post by John Ayers (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
There are many design rules of thumb I have heard over the years. For example: KISS (keep it simple stupid); make it idiot proof; be realistic with tolerances; do not make assumptions that are not realizable (zero gap for instance); and many more. The most important rule of thumb I have experienced is “common sense”. To illustrate my point, I have a few examples that are below. [Read more…]
Experiences with Belt Bucket Elevators
This article covers some of the problems that can occur with bucket elevators and provides possible remedies.
Bucket elevators lift bulk materials from one level to another.
They are used on powders, granules, grain, chip shaped products and lumpy materials.
They function well when designed properly for the duty, and used as designed. [Read more…]
Overview of Benchmarking
Benchmarking is the systematic process of observation and analysis.
The evaluation of a project, method or process best practices as performed by recognized industry leader may reveal improvement opportunities for your organization.
Benchmarking may focus on diverse business processes and with both internal and external subjects.
The intent is to understand what makes the subject’s process work well.
Understanding a system that operates well may reveal the elements in your process that may benefit with a change.
Keep in mind that not all best practice processes may apply to your specific situation. (Lapide, 2005) [Read more…]
Rewards and Incentives Have an Impact On Reliability
A maxim of business management is to measure what is important.
The focus on aligning metrics, rewards, and incentives is not a new concept. Many businesses create target focused incentives with the expectation it will assist achieving those important business goals.
In many cases, simply monitoring a metric improve the team’s ability to achieve a specific goal.
In some cases, though, achieving the goal and associated incentive has an associated negative impact on the business.
If you offer a bonus for a short-term behavior or goal and offer nothing to balance with the long-term impact.
Your incentive may actually damage your business in the long term. [Read more…]
Unintended Consequences of Risk Reporting
Guest Post by Geary Sikich and Joop Remme (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
Introduction
In this article we posit three questions. The first question is: “Is it a social responsibility of companies that they undertake a comprehensive risk assessment?” The second question: “Does the notion of conscience and its application to the generation and use of risk information and information in general, create an obligation for the organization to disclose the results of the comprehensive risk assessment?” The third question “How do the people in the organization communicate the information from the comprehensive risk assessment to stakeholders and yet preserve security and protect the organization?” [Read more…]
The Importance of Fit, Tolerance & Clearance
Many equipment breakdowns and stoppages occur because of improper clearance between holes and shafts.
The shaft is too tight in the hole; the center of the hole is not at the center of the shaft making it off-center; one part is loose on another and slips out of place or does not seal as it should. [Read more…]
Getting Started in Reliability Engineering
Initially, the CRE Prep blog aimed at providing refresher material for those preparing for the ASQ CRE exam.
In discussions with readers, it has become clear to me that many new to reliability engineering have found the series of articles useful.
That is should not be surprising since many of the tutorials are introductory and practical.
The problem those new to the field have is related with where to start.
There is a lot of information related to reliability engineering.
From defining reliability to working with teams to Weibull analysis, there is a lot to know. [Read more…]
The Side Swipe: When Innovation is your Wheelhouse
Many companies achieve great success based on their ability to create, invent, and develop a technology.
If this is the dominant focus of their product development programs they will maintain a high market share by continuing to be cutting edge.
These industries and technologies are highly competitive with respect to new features and functionality for a period of time, but the growth of any specific technology slows as it matures.
When this occurs, customers begin to put more weight on cost point and reliability when deciding which model or brand to purchase.
Are Prototypes Useful for Reliability Estimates
Prototypes are precious items. A vendor sample or beta version of factory parts may provide necessary insights.
They are not real though.
The prototypes and samples we hold, admire, examine and test are just a representation of the final product or system.
It is extremely rare we will learn exactly what we need to know with these few items. [Read more…]
