That question is asked often. The answer is as complex as the profession itself. There are many aspects of Industrial Engineering, but they are all related. The bottom line is that the end result of any project is a cost saving. Some savings are direct and some are difficult to quantify.
The Industrial Engineer questions if there is a better way to make a product and if it is able to be made faster and easier. Everything is questioned and the necessity determined. Is a tool of some kind better than using the hands, are the supplies located properly, are all the parts necessary? Can something be combined to make a single part. Make or buy?
At the very root of all of this is the time study. Time studies are performed so that each operation has a dollar and time value attached to it. This is the basis for costing, scheduling, manpower, equipment usage, plant layout and even operator payments, etc.
The Industrial Engineer is always mindful of the work environment. A safe working environment is essential for good production. The need for safe practices should be included in every operation. Some of those practices are directly related to the operator (safety glasses, gloves, etc.) and some are passive (machine lockouts, pullbacks, etc.).
As a result of all of this, the Industrial Engineer may be involved in:
Almost Anything Else
So what does an Industrial Engineer do? While an Industrial Engineer may not do everything within a particular facility, he will have more than a passing knowledge of most of the functions within that facility.