An article appeared in an engineering forum entitled Why Designs Fail. As I thought about the article and the examples presented, the Titanic, Tacoma Bridge, etc., I realized mitigating the consequences of a failure are more important than preventing the failure.
One of the subjects I did not learn in the classroom was Failure Mode and Effect Analysis (FMEA). I do not intend to cover the subject of FMEA but would like to emphasize one small portion. FMEA was introduced to me on my first jo
When something goes wrong in manufacturing after a long period with no issues we ask “who went on vacation.” Once that is out of the way we go to the drawings to get re-educated. Yep all the callouts are OK. But you continue to stare at the drawings looking for the problem source. The manufacturing engineer is contacted and he checks his shop paper. Machines have all been calibrated, correct cutter/abrasive is called out, and incoming inspection paperwork indicates material received is OK
My answer to that question would have been yes, and like all absolute answers, it would prove to be incorrect. An axiom in manufacturing is that the design engineer should not dictate manufacturing processes unless it is vital to the function of the design, metal vs. plastic, casting vs. forging etc. Once passed the gross requirements, dictating which machine tool to use would be beyond the design engineer’s prerogative unless there was a compelling reason! However, this should not be taken as t
Over the years I have witnessed a particular mistake repeated. It is usually with an old product that has a problem, or the old product requiring a change or a feature added. The mistake manifests itself with everyone believing they carry the true operation and understanding in their heads. Aside from Scotty aboard the USS Enterprise, most should assume there is something they may not know.
When a new product is being developed the team usually follows some development process with defined
I did not write the linked article. I should have since you will not learn this in school. When we finish 4 or more years of an ME education we are all wound up. We have been working at a pace which would kill us if tried it indefinitely. What shocked me when I entered industry was the trivia that engineers must be involved with. Perhaps like a soldier, you train to fight, but you don't do it 8-12/hr per day for 30 years. I don't know if the following article is accurate for small companies but
The link below is an article about the value of certification for manufacturers. It is a heavy sell for certification. In my opinion it misses the most basic benefit of certification, which is the path to getting certified.
Here I would like to touch on two subjects that came together during a single project. 1) Anticipating abuse of equipment and, 2) balanced designs. Abuse is self-explanatory. I use the term balanced not in terms of center of gravity but a design that has all components of similar strength or life expectancy. No single component is excessively weaker or stronger than the rest of the system.
A little background is required before the real
I get great satisfaction when working with my hands. When I do so I always ask why the item I am working on is as it is. One source of frustration I believe many have experienced it the lack of tool access. Sometimes n-1 fasteners are a breeze to access and the nth takes more time to remove than all the other combined.
I don’t recall from my machine design class ever addressing this real world situation. I learned how to size bolts, bearings, and cross-sections but I don’t recall any mentio
Recently I was interviewed by a Mechanical Engineering student on the importance of communications. I’m approaching 40 years in engineering practice so the examples began to flow and the student’s 15 minute time estimate for the meeting quickly turned into two hours. The meeting itself was a lesson in communications. My awareness of the root cause, that I will describe below, I believe made the information more valuable.
The student and I covered many issues on the topic of communications,
I have often said to young engineers that the tools we have today were not even science fiction when I first graduated. Now a 3D CAD system can easily create complex shapes. Before the 3D programs there where products with complicated shapes. This video explains how cars were designed and the number of man hours that went into it. This old video was the closest I ever got to the advanced design studios. This was high security as indicated in the video. When I look at designs of many old p
I recall many years ago first hearing the term Over Engineered. It rang a sour note but I had not given it much thought. I still hear this said today about older equipment. For instance the DC Generators at Pratt Institute in Brooklyn NY have been in operation for over 100 years. http://inspectapedia.com/heat/Steam_Systems_Pratt_Milster.php I had the opportunity a few years ago to visit my alma mater. To my surprise and delight the Chief Engineer who provided the tour of the facility to my class
Nearly Forty years ago, a fellow engineer told me a story that must now be 70 years old. This engineer was born and educated in Egypt. His first job was a large civil engineering project with massive amounts of earth moving. Having a formal education but no local real world experience, he started to estimate how many steam shovels and trucks were required for the job. A Sr. engineer asked, what he planned do with all the equipment once the project was done, and what about the 99 local laborers l
This is a follow-up to the article Anticipating Abuse and Misuse of Equipment and Balanced Designs. Here is where the design engineers thought they had a balanced design.
This story took place in Germany and told to me by a very senior engineering manager in the USA. The events may date back to the 1960’s or early 1970’s but the lesson is timeless. The warranty repairs for cars made in Germany by the American subsidy in Germany and driven in Germany were having unusually high manual
Since a lot of young people visit this forum I thought it could be of value repeat what I learned 40 years ago.
I did learn the following from one of my professors not in the classroom but during a meeting with her as my adviser. I did not fully appreciate what she suggested though I did follow her advice and it was the correct thing for me.
I was in a city community college (CC). The four year city colleges were somewhat prestigious. The CC prepared students to transfer within the cit
A warning by Dr. D. posted on this site reminded me of two funny incidents. Dr. D. was responding to the use of PPM for perpetual motion machine. These initials according to Dr. D. are used for Permanent Magnet Motor. This may sound trivial, but the following, I was not warned about in school.
If you have ever worked in big corporations especially defense or government related there are new languages you will need to learn. Shortly after joining a defense company, I told my boss if I did
I have been encouraged to contribute to the Mechanical Engineering web site by Dr. D. I have started the blog "Not Taught in Class". The purpose of the blog is to provide examples of lessons learned in the field that you would not learn in class. These stories are not white papers, just real life examples of things not expected and problems solved. The blog postings will also attempt to provide insight and perspective that comes with many years in the field of engineering. I hope the blog postin
As a young engineer I had just completed a lot of book learning and of course turned to my books for solutions once on the job. I have witnessed a similar focus on computer tools as 3D CAD and FEA. Both are valuable tools but you must understand the problem before the tools are applied.
During my early days as a mechanical engineer in the auto industry the Japanese where taking market share at an alarming rate. Motown was scrabbling for an explanation. Statistics became the jargon of the d
I have learned to take most news reports with a pound of salt. The VW diesel scandal may deserve at least a pinch of salt. That is my take from the attached article, “VW Dieselgate…”
Most who have taken exams to receive their medical, law, or engineering licenses would likely not pass the exam on any given day as normally administered. I am sure I could solve a sufficient number of problems to get a passing grade on a PE exam but not in the 8-hour window.
In the real world, our clients
This came to me via e-mail. I am sure little of this is 100% correct. But just think if just 50% are 50% correct.
The Exponential Age?
Just a few things for us all to ponder, especially the younger ones amongst us.
Did you think back in 1998 that 3 years later you would never take pictures on film again?
In 1998 Kodak had 170,000 employees and sold 85 % photo paper worldwide. Within just a few years their business model disappeared and they went bankrupt. Wha