Why You Should Do It Yourself
Qualitative mechanical design is done with layout drawings, whether made with pencil and paper or by electronic drafting (CAD). It is common for such drawings to start with sketches made by the design engineer and be converted to scale layouts by a drafter. The drafter may have any title from junior drafter to senior designer, depending on how much he or she is expected to add to the contents of the sketches. The design engineer then reviews the layout and asks for changes, and the trouble begins: "Why didn't you ask for that in the first place?" "Is it really necessary to make that change?" "Are you sure it's better?"
These are the symptoms of the drafter's disease this article has named "indelible pencil." Unfortunately it is not terminal unless it is so acute that it results in termination. It is related to having a low innovation index.
One of the reasons for your making changes is your ability to criticize an interim design, not just on the basis of easily described reasons but because of your judgment based on experience, insight, and general gut feeling. Try using that as an explanation to the drafter.
You, the Board, and CAD
You need to learn to look upon the drawing board or CAD terminal as a laboratory for trying ideas out to scale. If it is prestigious in your company to "get off the board," the prestige is wrong.
If CAD drafting is used in your company (and it is becoming universal), you must learn to use it yourself, and that can be a time-consuming and tedious task. If you do not and so require an intermediary between you and the drawing, CAD is a liability rather than an asset because you may end up with good documentation of poor products.
When Do You Stop?
One of the universal problems of design is the decision of when to stop improving (iterating) and release the design for manufacturing. Bright engineers are apt to keep generating improvement ideas forever, but you have to stop sometime and build the product or your company goes broke.
You wish you knew a formula. The conflict pits the cost in money and time versus the incremental benefits of the latest ideas, usually an apples-and-oranges comparison unless you can estimate both in terms of our universal parameter, money.
A compromise
One way to have your cake and eat it too is to freeze the design for a first batch of product and then phase in improvements in batches. Another procedure is to phase in each improvement at an optimum time for that improvement. Of course, the obstacles to introducing changes after production starts include scrapped inventory, scrapped or reworked tooling, time lag in generating new inventory, documentation, customer notification, and testing cost and time.
The problem is a severe test of management judgment, particularly for managers who like engineering.
