Your Reliability Engineering Professional Development Site
Find all articles across all article series listed in reverse chronological order.
The planning of environmental or reliability testing becomes a question of sample size at some point.
It’s probably the most common question I hear as a reliability engineer – how many samples do we need. [Read more…]
Estimating the set of stress and stress curves is an interesting exercise that may have a greater purpose: safety.
The connection is clear when considering the potential consequences of failure.
For example, the loss of braking power when landing an aircraft may result in the aircraft rolling off the end of the runway. This could be into a river or road and may have a rather poor outcome not only for the aircraft. [Read more…]
Becoming an ASQ CRE is one milestone in your career. It involved gathering experience and studying the broad reliability engineering body of knowledge.
It also involved an ongoing application of what you know and learn. I’ve found being a reliability engineer involves learning about materials, designs, systems, people, and tools & techniques. Mastery takes time and a good library. [Read more…]
Ideally, in every design of every component, the stress–strength relationship looks like this figure. The stress is well below the strength.
This implies there is very little chance of failure due to the element being overstressed.
Also, ideally, we fully characterize all stresses and all strengths for each element of a product. This is generally difficult to accomplish and it is rarely done to that extent.
Every once in a while I see a comment that by following the HALT methodology you will “over design” a product.
Many question at what point or operational limit do you quit increasing the stress-strength margins. Those who hold this view of HALT do not understand the essence of what was Gregg Hobbs’ principles and paradigm shift. [Read more…]
Embarking on a product development project contains many aspirations, including that the product should work as expected.
The device functions and does so over time. Enough time for the customer to deem the device reliable.
That is one way to approach setting a reliability goal for a project. Estimate what will delight the customer. Set a target for how long without failure your new design function.
The goal provides a focus for the team. [Read more…]
Reliability or life testing involves estimating the expected durability over time of an item.
This may be an entire system, a product, or an individual component. We may also focus on an element of a component, such has a material property.
At the end of the testing, we want to say something meaningful about the expected performance over time. [Read more…]
Many years ago people would complain about “cheap Japanese” products, but today few people would associate Japanese brands with poor quality.
The turn-around is widely attributed to Deming, and Taguchi, and Juran, and other evangelists who taught not only the tools and processes but also the long-term benefits that can be realized when a company adopts good practices and a culture of quality.
Today I hear people complaining about poor quality in Chinese-made parts and products, and there have been several widely-publicized incidents (see Aston-Martin and counterfeit parts).
Many customers have decided to move their production and seek part suppliers in other locations, including “re-shoring” to North America, in part because they’ve concluded that any cost savings due to cheaper labor are outweighed by the costs of poor quality.
It’s hard to say whether this will have a negative impact on the worldwide consumer perception of Chinese brands such as Lenovo, Haier, and others.
A common question concerns the warranty period.
How long should we, the manufacture guarantee that our product will work as expected? Do we include limitations or not? How do we decide? [Read more…]
Highly Accelerated Life Testing (HALT) is a technique to expose weaknesses or faults with a product.
HALT uses individual or combined stresses in a step stress approach to quickly apply sufficient stress to reveal defects.
HALT is not a specific chamber or fixed set of test conditions. It is an exploratory process to reveal weaknesses in a design.
The product development process naturally includes a check step, to determine if the expected functions of the product work as expected.
Some teams then add a measured amount of stress (temperature, vibration, dust, load, etc.) to the product to explore functionality at elevated stress levels. [Read more…]
Here’s a short list of terms related to warranty management. Often is the words we use that matter and understanding the language of warranties is one step in mastering warranty management.
A promise made to the buyer of an item that the manufacturer (seller) will repair or replace the item if necessary within a specific time period. [Read more…]
A recent LinkedIn discussion addressed the question of the best strategy for dealing with poor supplier performance.
A lot of the respondents seemed to advocate a punitive approach, either threatening the loss of future business if performance doesn’t improve, or combing through the terms & conditions of the contract for enforcement language.
I’ve always thought that there’s a lot of similarity between managing suppliers and managing subordinates, and I wonder if some of these same people threaten their teams with punitive actions when individual performance doesn’t meet expectations. [Read more…]
In short, you probably do, better reliability performance the better the brand image.
When I’m making a purchase I prefer to buy items that I either have personal experience work well over time (reliable) or have many comments and reviews noting the durability.
As a reliability engineer, I am often asked what kind of car I drive (a Toyota Highlander, if must know). Reliability does matter -not only to me- it matters for many making a buying decision.
When a product’s actual reliability performance exceeds the customers expected reliability performance, the customer may consider the product reliable. This experience builds and when supported by other experiences from the same brand, increases brand equity. High brand equity permits a price premium, increased brand loyalty, and increased positive word of mouth support. [Read more…]
When making a transaction there is an element of trust.
The buyer is trusting you are providing a product that lives up to the claims provided. Neither party wishes to be duped. Yet, we do enter into transactions. We buy stuff.
A few hundred years ago and prior most purchases were from someone you knew, and most likely knew well. It was in the craftsman’s best interest to maintain honest dealing and create quality products. If not, they would enjoy less business. [Read more…]
Why do so many avoid failure?
In product development of plant asset management, we are surrounded by people that steadfastly do not want to know about or talk about failures.
Failure does happen. Let’s not ignore this simple fact. [Read more…]
