I don’t blog much about work. Not because interesting things don’t happen there, but I would never want to cause my employer difficulty by anything I might inadvertently say.
However, some of this last week holds lessons that deserve to be told.
My job entails a lot of different activities. A small company finds value in one person who can do many things, and often a willingness to learn will keep you in a job. I have around 34 years of experience as a mechanical designer / draftsman. Now-a-days, I also do in-house sales, purchasing, and all things computer. And what have you.
This last week, I wound up working on the design of a tensioning idler for a large belt drive. This has to consist of a (in this case) fairly large roller with bearings that has to be adjustable in such a way as to push against the belt drive and exert a certain amount of force. There are a number of different ways to do this, as you will see.
My initial idea was to use a swing-arm arrangement similar to the swing-arm on a motorcycle, but larger. This would provide stability in every direction it needed to be rigid, while allowing free movement in the direction it needed to press against the belts. It is a proven design that I knew would work on the first try.
That idea went by the wayside as too complicated and expensive. So then, my boss and I came up with a simple arrangement of a roller being pulled down by four threaded rods with nuts. I had some doubts about whether it would work under the loads involved, but it wouldn’t cost much to try it. So I modeled it in Solid Edge, which took about a day (elapsed), and we showed it to our customer. He didn’t like it, so we abandoned that idea. We are now two days into this, and are starting over. I am a bit frustrated by now, even though this is the nature of the business. This ain’t my first rodeo.
So my boss and I talked it over again, and I began modeling the swing-arm idea. This would have worked, but just about the time I finished modeling it, our customer called my boss and put forth his own idea, which was for a vertical guided slide arrangement. So we abandoned the swing-arm idea (again) and started over (again). 2 1/2 days into it.
This final idea, once modeled and some details were worked out, everybody liked. It will work. So tomorrow morning, I will be detailing it out for production, and purchasing components.
All of this happened under severe time pressure. Our customer is losing money when this equipment is not running. Machine-shop and purchasing lead times are a factor in the design.
This true story demonstrates some of the fundamental things about engineering and design that they don’t tell you in school.
- Design is a collaborative, iterative process.
- You are not usually in control of the design process – whoever signs your check, and his customers, are. Get over the ‘not-invented-here’ syndrome. I got over it about 30 years ago.
- Your input does matter, though – they will listen, if you shoot their ideas down. As long as what you are saying makes sense. By the same token, you must listen when they shoot your ideas down.
- There is a lot of ‘wasted’ time involved in the process; this time is not truly wasted, but is the result of following a design far enough to detect its inherent flaws. Don’t get frustrated when this happens, it’s part of the job. If you hit a show-stopper, abandon that design.
- Sometimes, the ‘too many cooks’ syndrome kicks in. This can be detrimental, but often it is actually helpful. One of the most important parts of design is that of ‘critic’ – finding the flaws that will make it fail BEFORE you go to hardware. More minds applied to this process is almost always helpful. Don’t take it as criticism. Your pride is in the finished product. Any valid criticism before then should be welcomed.
- When it’s in hardware, you will find out what you overlooked. The shop is always in a position to find your mistakes.
In a small company, at least, you are almost never allowed to work on one thing continuously. All of the above was interspersed at random intervals with phone calls, sales work, purchasing activities, and new jobs that needed to be processed. Multitasking is essential, even though it hurts your efficiency.
Life is like that. I sure was glad when the weekend got here, because it was an intense week; but I feel pretty good about the design we came up with.