Your Reliability Engineering Professional Development Site
A listing in reverse chronological order of articles by:
The analysis of residuals helps to guide the analyst when analyzing data. It provides a way to select the model, analyze the data, develop parameter estimates, and to develop confidence in the results. [Read more…]
Perry defines Design of Experiments with one simple statement.
“A tool to assist in the process of understanding a system.”
Just 2 minutes and 10 second long, lets break down and understand each phrase in this basic definition of design of experiments. [Read more…]
Memory circuits store 1’s and 0’s for you so that you can retrieve them later. The 1/0’s can represent data or instructions.
Today, no computing device operates without some memory. Memory devices store pictures, music, documents. How many USB (Unified Serial Bus) memory sticks do you have scattered on your desk?
Semiconductor memory comes in many flavors: Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), Read Only Memory (ROM), Erasable Programmable Memory (EPROM), NAND/NOR Memory (a.k.a. Flash), Solid State Drive (SSD). Without power volatile memories like SRAM and DRAM lose their stored values. Non-Volatile memories retain their stored value when power is absence. [Read more…]
Semiconductor Integrated Circuits (ICs) can have millions of digital circuits which can translate to billions of transistors.
I know these numbers can be intimidating, but I assure you the challenges of testing ICs started in the mid-late 1970’s. Lots of effort has been put into Electronic Design Automation (EDA) systems and Design for Test (DFT) techniques to manage the development and application of digital circuit testing.
In the beginning these software programs and DFT techniques used the Stuck at Fault Model. [Read more…]
Here is an example of a common engineering development task. A design engineer needed a life test plan for a switch verification in a safety system. We jointly developed a plan by taking a system view of the component function, considered corporate and regulatory requirements, customized it to the supplier’s test capabilities, executed the plan, and made design changes to remove product defects. [Read more…]
Depending upon the type of engineer you ask the word test evokes a different notion of goals and expectations.
Engineers who work on the design of semiconductors test that their designs meet the specifications.
This can be done pre-silicon and naturally verified in-depth on silicon.
Engineers concerned with manufacturing of a product test to find defects and to verify performance.
Similar approaches can be taken by both engineers though there exist differences in the amount of time. To be cost effective, a manufacturing test must be completed in as short a time as possible. Let’s continue to compare and contrast design validation with manufacturing test. [Read more…]
Before embarking on a complicated task one needs to have the basics understood.
In the musical “The Sound of Music,” Maria teaches the Von Trapp children to sing by first teaching them the musical scale.
She quickly discovers that the basics really do need to be learned one note at a time.
By the end of the “Do Re Mi” song she has them singing harmony while she sings a new melody with the words “When you know the notes to sing, you can sing most anything.” [Read more…]
Sometimes we get so used to managing without things that it becomes the way things are done. An astronaut giving a presentation at a conference I attended referred to this as “normalization of deviance.” In other words, we get so used to the way things are, that either right or wrong, they become the norm! Unfortunately, the obvious is many times ignored – because it is obvious. If you intend to have a sustainable Root Cause Analysis program, then there are things that must be done. People must be trained, reports must be written, analyses must be performed, and progress must be tracked and reported. Until a program becomes self-sustainable, it must continue to be driven. [Read more…]
Telematics data analysis can be used to improve our understanding of how people use their vehicles. It is an objective source to validate product requirements. In cars and trucks, sensor signals are read by electronic modules share the data on a CAN bus. Some signals contain data for continuous variables. Some examples of continuous variables are vehicle speed, engine speed, engine torque, ambient temperatures, in-vehicle temperatures, pressures, voltages, and the battery state of charge. Another name for the continuous variables is parametric data. This CAN data is a rich source of information
As with other programs, an RCA program needs to be driven from the top and supported through all levels of the organization. This includes upper management, supervision or mid-management, and those on the front line doing the [Read more…]
In my prior article, an overview of vehicle telematics was provided. Telematics data includes time stamped records and fields containing count or parametric data recorded from the vehicle CAN bus. The count data is always a non-negative integer and the parametric data is stored as real numbers, generally in scientific format. This article focuses on the analysis of counting data.
Count data is used to monitor events, i.e., the number of trips, the days of operation, the calendar date, door open/close cycles, the number of engine starts/stops, or other variables. So, if a variable is selected for analysis, how can it be analyzed and a vehicle be characterized? How can fleets be analyzed? Can vehicle usage percentiles be determined?
[Read more…]
This is the first in a nine-part series of articles. This first one will lay out what I think are essential characteristics of an RCA program. The other articles will follow up on each of the items in some detail.
Have you ever felt overwhelmed with too much to do? I imagine most of us have struggled with time management at one time or another. There are just too many things on our plate, and they never go away.
Some may attribute this burden to their life, or perhaps they are inefficient time managers, or something else. Regardless, I doubt many enjoy the feeling or the situation.
If only we could walk across the bridge to self improvement and be enlightened.
Product design, development, and reliability engineers need to verify that their product meets specifications, which include dimensional requirements, functional definitions, and life testing. How are the requirements validated?
Telematics data is collected to show how a vehicle has been operated. Fleets and retail data are stored on servers for engineering analysis. This data can be used to set new requirements or validate older requirements.
In my last article, RCA Templates Use or not?, I discussed templates and suggested that while beneficial for many things, they may not provide as much value for those doing RCA’s. This is because for any specific effect, the variability in the cause tree is significant and difficult to predict. This doesn’t mean that there are no options to utilize templates to help speed up the process, but perhaps not in the way that people might be used to. [Read more…]