Your Reliability Engineering Professional Development Site
Beyond the part reliability specification, you may also add conditions or requests to your reliability specification for your supplier.
The communication with your supplier should include sufficient information that they fully understand your reliability performance expectations. When buying or contracting with a supplier, you are the customer.
Be clear about your reliability requirements including constraints and conditions. [Read more…]
Unless you are working with raw materials directly, you rely on your suppliers to provide reliable parts.
Do you suppliers know your reliability objectives for the parts they supply?
If you didn’t tell them, they probably do not know. If you did tell them, did you make it the reliability specification clear and understandable?
As with any specification, clear communication is essential. Guessing or assuming both parties know and have the same reliability goals is, well, not a good practice. The ability of a supplier to build and deliver the parts that meet all your specification has to include a clear and understandable reliability specification.
There is a range of common reliability specifications in use, some are better than others. Let’s start with a brief review of reliability specification types.
Then briefly outline how you establish the reliability specifications for each supplied component. [Read more…]
Even products with relatively quick design cycles and short stays in the market deal with part obsolescence.
Long design periods along with long durations in service or in production simply increases the chance that one or more parts will become obsolete.
Designing systems with part obsolescence in mind helps. Working with suppliers to select parts with many sources, with long-term plans to produce, and with long term commitments, all may help. Even then, companies change priorities, go out of business, or simply discontinue the part you need. [Read more…]
One aspect of creating a new product or system is the sourcing of parts, components, and materials.
Gone are the days of your organization providing every element of the final product. Henry Ford’s supply chain for early Ford automobiles includes their own forests, rubber plantations, and iron ore mines. [Gelderman, 1981]
We increasingly rely on the supply chain to create the necessary parts for the design’s functionality. Then to continue to supply those same parts for decades, in some cases. [Read more…]
Software elements of a product or system take time to create. Thus re-using blocks of code developed for previous applications may save on development time. [Read more…]
A fault tree analysis (FTA) is a logical, graphical diagram that starts with an unwanted, undesirable, or anomalous state of a system.
The diagram then lays out the many possible faults and combination of faults within the subsystems, components, assemblies, software, and parts comprising the system which may lead to the top level unwanted fault condition. [Read more…]
Physical products are made up of materials.
The materials including metals, polymers, adhesives, and many others experience loads and stresses during assembly, transport, storage, and use.
Selecting the right materials such that they both meet the needs of the customer and are sufficiently reliable relies on understanding how the material will respond to the applied stresses over time.
As with parts selection, one way to determine if a material is suitable for your application and end use is to monitor the material’s performance over time in your products. The trouble is it also transfers the risk of failure (the unknown risk of failure) to the customer.
In many cases this is unacceptable. [Read more…]
A product or system may fail for many different reasons.
One cause is a faulty part. A component is susceptible to failure when either improperly used in the design or is a damaged or flawed component. [Read more…]
When products were crafted one at a time, the design and manufacturing process was often done by the same person. The craftsman would design and build a chest of drawers or carriage.
Some trades would employ apprentices to learn the craft, which included design. Larger projects may include an architect or lead designer along with a team of engineers.
Yet the shop or site for the railroad engineer or bridge was not far allowing close communication between the ironsmith and design team. [Read more…]
I’ve often said, “reliability occurs at the point of decision.”
At the point of design during the design process. At each and every decision.
The design team of engineers establishes the bulk of the reliability capability early in the design process. The team’s decisions about materials or shape, concerning inventions or outsourcing, about how and where to build the product, and many more decisions impact the final product’s reliability performance.
Reliability is designed into the product right from the start. [Read more…]
Let’s start by understanding the difference between engineers and engineering designers.
The work we do as reliability engineers may require a different approach when working with these different types of engineers. [Read more…]
The ability to assemble a system to meet the functional requirements is constrained by the design, the materials, and the tolerances.
Some designs are impossible to assembly. While other designs take little effort to build. The discipline of design for assembly, DFA, applied during the design process can enhance the manufacturing process. [Read more…]
People build, transport, use, maintain and dispose of equipment or products.
Thus the creation of these items should include consideration of the humans involved. In order to fully benefit from the functional capability of an item or system, we, as humans, have to interact with an item’s interface, displays, sounds, etc.
Whether a smartphone or bottling machine, the ability to provide commands or direction, the ability to recognize and understand responses, and the ability to correctly identify faults or outputs all combine to permit humans to place calls or fill juice bottles.
It is in the design stage that the elements of a piece of equipment (hardware or software) thwart or enable efficient human interaction. [Read more…]
In 1968 NASA explored where machines and humans would best achieve tasks primarily during space missions. Many of the findings are true today, and in some areas, the differences are blurring.
Machines created by humans continue to improve and take on complex tasks, that once only humans could do. For example, parking a car, now a feature of newer car models. Autonomous driving is happening and continuing to improve. The ability to reason, to foresee and evaluate risks, once thought to be strictly in the domain of human capability is now being done by machines. [Read more…]
If a human is going to build, install, monitor, use, operate, repair, or dismantle, then the design team must consider human factors.
According to Wikipedia
Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.