Your Reliability Engineering Professional Development Site
Find all articles across all article series listed in reverse chronological order.
With the design FMEA complete, the equipment should have high inherent reliability. The equipment can then be installed in the plant, and provide a high level of performance to the business, at least initially. This is where Maintenance comes in. Maintenance can enable a low Life Cycle Cost, by preserving the reliability of the equipment. [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.
You may have been tapped one morning and given the assignment. You may have pursued the role either via a university program or by simply applying for the position.
Now what? How do you start in this role? What are you expected to do? [Read more…]
Products and equipment start with a design. The functions and performance occur or do not occur according to the capabilities designed into the system.
I learned early in my career, as a manufacturing engineer, that some products were much easier to manufacture (less yield loss) than others, and it was often the design of the product that made the difference. [Read more…]
Maintaining high reliability or availability is a marked advantage for any system. A system that achieves the ability to avoid system downtime due to a single failure event, is essential in many applications. Yet, the fault tolerant capability comes at a price.
A system that achieves the ability to avoid system downtime due to a single failure event, is essential in many applications. Yet, the fault tolerant capability comes at a price.
Here is a short list and brief description of fault tolerant design disadvantages:
The nature of a fault tolerance design is to continue to operate normally even with a component failure.
Thus if the ability to detect a component failure relies on a loss of function or capability, it may be difficult to detect the failure. This sets the stage for a second component failure to cause a system downing event. [Read more…]
A common and poor technique to gather field data is to count the number of returns by week or month. This can provide a graph showing the number of returns over time.
It hides information you need to understand your field failures.
Let’s take a look at a way to gather the same field failure data and retain the critical information necessary for time to failure analysis. [Read more…]
Implementing a new reliability development paradigm in a company which is using traditional, standards-based testing can be a perilous journey.
It is especially true with introducing HALT (Highly Accelerated Life Test) in which strength against stress, and not quantifying electronics lifetimes is the new metric. Because of this significant change in test orientation, a critical factor for success begins with educating the company’s top [Read more…]
In the article, Hypothesis Tests for Proportion, the comparison is between a given value and the sample. In this case, let’s compare two populations. We take a sample which provides a proportion representing each population and determines if the populations are different from each other based on the two samples.
The exact solution uses the Binomial distribution, yet when np and 1 – np are greater than 5, then we can use a normal approximation for the test statistic and critical value. [Read more…]
Often time’s equipment is procured, setup and put into operation with a single focus on reducing the initial capital expenditure. This can be a fatal mistake as the reliability of the equipment is built into the design of the equipment. This called the inherent reliability. Once the equipment is designed and installed, there is little the maintenance department can do to improve the inherent reliability. [Read more…]
Fielded products fail day by day. Customers report these failures generally seeking a way to remedy this issue. Gathering the reported or returned products or confirmed failures is common practice.
Depending on the product a simple replacement or exchange may suffice. For other products, repair or a refund may be appropriate.
In general, and not always, when a product fails in the hands of a customer, the organization designing, manufacturing and distributing the product learns of the failure. [Read more…]
In the previous article, What is Reliability Optimization, we defined the concept. One of the elements of optimization is identifying which elements of a system to focus improvement efforts on.
Simply improving every element of a design may provide an overall improvement of reliability performance.
Given constraints such as time or funding, selecting the specific few elements that would provide the most improvement is key. [Read more…]
On occasion, you and the team sit down to review the design.
The idea is to check the design for any issues with the combined wisdom of the people involved. Or, it may be a status update for the entire team providing a focus on the most important issues and action items.
The review may involve all departments, such as marketing, operations, supplier management, and the design team.
It may involve just you and the electrical engineer in a private meeting. In either case, it is a review and a chance to illuminate salient reliability issues and form a consensus on the appropriate action. [Read more…]
It is easy to understand why the term HALT (Highly Accelerated Life Test) is so tightly couple to the equipment called “HALT chambers” systems. Many do not think they can do HALT processes without a “HALT Chamber”. Many know that Dr. Gregg Hobbs, who coined the term HALT and also HASS (Highly Accelerated Stress Screens), spent much of his life promoting the techniques and was also the founder of two “HALT/HASS” environmental chamber companies. [Read more…]
Delivering the best reliability performance within the various constraints imposed.
Without constraints such as budget, time to market, customer expectation, product functional capabilities, and product weight, you certainly could design and deliver a highly reliable product.
There always are constraints.
In the Oliver Wendall Holmes poem, The One Hoss Shay, the deacon procures the strongest oak, the supplest leather, and the best of best materials. Cost was not a constraint. And the shay lasted 100 years to the day.
If the technology permits there may be stronger or more durable components available for a price, yet cost is often a limiting factor. [Read more…]
A plan is a guide or roadmap for intended action.
A reliability plan is also a collection of specific tasks and milestones and enhanced with a rationale to allow the entire team fully understand their role accomplishing the reliability objectives.
The plan is a way to achieve the desired business objectives. Meaning the product is reliable enough to meet customer expectations, minimize warranty expenses, and garner market acceptance. The plan is just a plan, it is the accomplishment of the tasks, the decision which improves the design, the signals monitored that stabilize the supply chain and assembly process, that make the difference.
A plan without action is not worth the effort. [Read more…]
