Your Reliability Engineering Professional Development Site
Find all articles across all article series listed in reverse chronological order.
Technical drawings and electrical specifications often include tolerances.
The range of values allowed for a particular aspect of the part.
Reliability engineers do not set the tolerances, yet we should both understand and influence them.
A critical element of design for reliability is the creation of a robust product.
It is not just robust in the end use, your product should also be robust to the variability that will occur during manufacturing and transportation. [Read more…]
If you are like me, then you have at least once found yourself struggling with Reliability & Maintenance(R&M) in a plant. Whether you are trying to implement planning & scheduling, manage spare parts or develop effective PMs, it can be frustrating. Not to mention how difficult it is to tie all of the different pieces together and making it stick.
The intention of this blog and website is to provide information on not only the different parts of a R&M program, but how they all tie together. This is what separates the profitable manufacturers from the ones that close. Preventing these closures is what High Performance Reliability and myself want to do. [Read more…]
Guest Post by John Mason (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
The audit is finished, the exit meeting conducted and the audit report has hit your desk. As discussed, there should be no surprises, there should be correctly categorized findings, and specific examples.
Now you have 3, 6, 9 or 12 months in which to fix them.
If you have findings that have to be addressed within 3 months, then you have got a nonconformity or a major corrective action (of course the names are different for every certification service provider). [Read more…]
The very best asset managers have maintenance under control.
Their entire organization’s systems and methods are tuned to preventing unplanned stoppages. They only do that which has first been thought through and prepared for.
But most importantly they understand the key factor to excellent asset care and work toward it continuously and energetically.
Keywords: preventative maintenance, reliability-centered maintenance, RCM, total productive maintenance, TPM. [Read more…]
Did you shake a wrapped gift as a child?
Sometimes the rattling sound may indicate the hidden contents. A sweater from Grandma would make a muffled sound, while a new Lego set would rustle the many parts.
Your customers may not shake the package to guess its contents, yet your product will experience vibration and shock.
The environments of assembly, transpiration, use, maintenance, etc all include shock and vibration inputs to your product. The operation of your product may include producing vibration and shock loading across the product.
Understanding the basics of vibration and shock will assist you to design your product to operate as expected in the noisy, shaky world.
The rattling about your product experiences is just one of the many environmental and use factors. [Read more…]
Reliability engineers all have a start.
A point zero.
The transition point from pursuing something else, or nothing at all, then we begin our journey as a reliability engineering professional.
Getting started can be difficult and at times overwhelming.
Then you find Accendo Reliability and there is a lot of great content, maybe too much. So, this short article has the intent to create a starting point for you.
Plus, for those well along in their career, a request.
What is your advice to those just starting their career? My plan is to gather the advice from this community and assembly a start here guide just for those just starting their career.
Leave a comment below with your words of wisdom. [Read more…]
A term that I use when describing product goals that are tangible and drive program decisions is “Product Asset.”
A Product Asset is “a fundamental attribute of a product that can be characterized as a quantitative measurable goal.”
The five Product Assets that I commonly select are the following:
Weld preheating is the purposeful application of heat to warm metal to a desired temperature prior to welding.
Preheating slows down the cooling rate of the weld and gives the metal more time to form a good microstructure, release internal stresses and dissipate hydrogen from the weld.
Keywords: thickness, weld puddle, cooling rate, temperature. [Read more…]
Guest Post by Paul Kostek (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
One of the keys to a successful project is having a set of requirements that are well defined and stable. We’ve all worked on projects where a lack of defined and controlled requirements has led to scope creep which result in schedule delays.
The requirements development process must also include mitigations for the risks identified in the Risk Management Plan. To accomplish this the initial risk assessment must be completed before the requirements development process begins. [Read more…]
Materials expand or contract with temperature change. Water expands as it freezes, whereas steel contracts as it cools.
This motion can limit the life of your system.
Materials and mechanical engineers include the expected motion into their designs, well the better engineers do.
Even centuries ago, craftsmen used expansion slots or features when attaching wooden table tops to their frames.
The motion due to temperature change will occur and has the potential to create immense strain within your product. [Read more…]
When your reliability program is working well, it may be difficult to recognize the benefits incurred.
Likewise, when the program is not working, it is obvious.
As you work to improve your program, keep in mind you may need to include elements to ensure your efforts remain visible.
I don’t mean staging field issues that you can solve quickly, rather that you are able to show the impact you and your program make to the organization. [Read more…]
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…]
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…]
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.
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…]