1. Summary
(MIN ZHANG)
I have been working as a Mechanical Engineer (or designer) for over 20 years in the field of:
 Heat exchangers.
 Fans and Blowers.
 Heavy duty vehicles.
 Vibration-isolation controls.
 HVAC equipment.
In this summary, however, I’m not going to talk further about this part of my background. If
interested, anyone can find more details from my work background. I’ll focus on another part
which is relevant to all the above designs – design method.
What I mostly heard on comments of my past jobs is that Min has his own way in designing.
Same CAD design software, in his hand, it’s more powerful. He has developed many macros
which help (himself and coworkers) a lot on the designing.
What is a macro? Why the macros make me special? I can say that many people, including
many engineering managers, don’t know what it is and why it has something to do with
mechanical designing. Well, it’s ok. As long as they remember, these macros I have created
might greatly improve the design efficiency and accuracy of the whole design team.
When you want somebody to do some work for you, you open your Email program and you
send him a message in a language that he understands (English, French...). When you want
AutoCAD (Inventor, Excel) to do some work for you, you open the Visual Basic Editor and you
develop a program in a language that AutoCAD (Inventor, Excel) understands. This program is
called a macro.
I have developed many macros in my life. I created these macros because I want to finish more
design jobs and I want them with less error. Just that simple. If this is also what you want.
Please continue to read, it won’t waste your time.
As a Mechanical engineer, I designed a lot of sheet metal parts. When the design of a sheet
metal part is completed, it will experience two manufacturing process before become the final
part: punching on a punch press and bending on a brake press. You’ll have to prepare two
drawings too. Our practice is to put them on two separate sheets of a drawing. First sheet for
brake press operator and the second sheet for punch press operator, or the vice versa, it really
doesn’t matter. This second sheet is an important reference to the operator because it contains

2. a flat pattern of the sheet metal part, with all the dimensions such as overall sizes of the part,
size of all holes and their centers position; bending information, etc. To create such a sheet, it
takes time, and you may miss some dimensions by mistakes. So I give the job to a macro,
activated by a button in the menu bar. Click on the button, the second sheet will come out
itself, with all the information, nothing missed. And the macro will decide the scale and
orientation (longer side of the flat pattern stays on horizontal) too.
It is a macro. It looks like you give a task to somebody for help. After 20 minutes later, he comes
back with the expected result, but actually the task is done by machine and it takes only 5
seconds! Why not? The more the better!
That’s true. I have a lot of macros for different tasks.
One macro is to draw an AutoCAD drawing based on dimensions and options in an Excel
spreadsheet. And the drawing is, of course, to scale;
One macro is to calculate the straight length of a tube part before it is bent, and then
automatically fill into a table in the drawing;
One macro is to show only sheet metal parts in an assembly file. The other macro is to hide all
purchased parts;
One macro is to list the bending radius of all the sheet metal parts in an assembly file or a folder.
The other macro is to find how many bends there are on each part in a folder, and then fill the
information into an Excel spreadsheet.
Is it like extended functions of the CAD software? And these functions are developed for me for
my company only! Because the other company may not need a tube drawing that requires the
straight length of the tube!
Your company need these extended functions too in order to speed up the design and to catch
more errors.
Some people asked me if I have IT background. I replied yes, although I have never worked as a
programmer. Developing these macros is absolutely a skill learned in order to do my jobs more
efficient. Once I developed a small macro, and realized how greatly it works, how can I stop to
develop more? In a design process, a macro can reduce 20 or more steps to one single step! Is it
amazing? Especially if these steps are used very often. Right now, I cannot do any of my jobs
without my macros!
Making my design work more efficient is not the only benefit of these macros. The other
benefit is accurate. If I have to open 100+ drawings to read some information from the
drawings, I’ll definitely give the job to a macro. Some macros can even look for potential errors
and report the results, so I can modify my design.