The work of industrial engineers falls under any of the following categories:-

Quality Control
Statistical Process Control
Productability
Motion Economy
Research & Development

Industrial engineers are usually involved in any of following activities :-

Devising better methods and facilities for manufactring and services. They study the various industrial processes involved and use mathematical models and computer simulation to devise new manufacturing systems that are more efficent.

They are involved in automating a production process. They first have to determine what aspect of production needs t be automated and if it makes financial sense. As an industrial engineer they also decide as to whic machine fit the requirements.

They figure out the best possible system for handling and storage of raw material, setting inventory size as well as packaging and the physical distribution of goods and services. In addition to these they are responsible for worker safety and quality work environment.

They determine the most effective ways for an organization to use the basic factors of production- people, machines and materails to make a product or provide aservice.

Industrial engineers determine the suitability of location for factories depending on the best combination of raw material availability , transportation and other costs.

In actual plant design , an industrial designer figure out which computer systems, machines and automated eqipments will be used in the design and manufacturing process. They determine the most effective layout for computers, equipments and offices such that it is flexible and easily maintainable.

They calculate how much work each machine or worker should deliever and if necessary initiate the use of automation and robots. They aid in financial planning and cost analysis, design production systems as well quality control procedures.