1  What Is Industrial & Manufacturing Engineering?

Week 1 Sample draft — replace with instructor draft ≈ 25 min read

Industrial engineers study how people, materials, information, and machines flow together to create value.

ImportantLearning objectives

By the end of this week you should be able to:

1. Define industrial engineering and manufacturing engineering in your own words.
2. Describe at least three industries where IMEs work and what they do there.
3. Explain the terms throughput, cycle time, bottleneck, and utilization.
4. Find the bottleneck of a simple process and estimate its maximum throughput.

Story from the field

The engineer who redesigned the kitchen

Lillian Gilbreth began her career studying factory and office work with her husband, Frank. Using film and multiple-exposure photographs, the couple broke jobs down into elemental motions they called therbligs, and then eliminated the wasted ones. After Frank died in 1924, Lillian applied the same motion study methods to housework (National Museum of American History, n.d.).

In the kitchen she placed the stove and counter side by side, put food storage above and pans below, and kept the refrigerator a step away. Cooks could then work in a tight loop instead of walking back and forth across the room (Hafner & Mayer, 2023). If your kitchen has an L-, U-, or galley-shaped work area, you are living with her ideas.

Why it matters: IE isn’t only about factories. Wherever people do work, there’s a system that can be studied and improved.

Source: Smithsonian National Museum of American History

1.1 Engineering systems, not just things

Most engineering disciplines are named after what they design. Civil engineers design structures, electrical engineers design circuits, and mechanical engineers design machines. Industrial engineers design how everything works together.

The Institute of Industrial and Systems Engineers (IISE) gives the field’s classic definition:

Industrial and systems engineering is concerned with the design, improvement and installation of integrated systems of people, materials, information, equipment and energy. (Institute of Industrial and Systems Engineers, n.d.)

The key word is system. A hospital emergency department, an Amazon fulfillment center, and a combine assembly line are all systems. Each one transforms inputs into outputs through a series of steps, and each can be made safer, faster, cheaper, or more humane. An industrial engineer practices systems thinking, which means asking how a change in one place ripples through the whole system.

Manufacturing engineering is the closely related discipline that focuses on the processes and equipment that physically make products: machining, molding, welding, additive manufacturing, and automation. At NDSU, the two fields share a department because modern production needs both. Someone has to design the process, and someone has to design the system it runs in.

Table 1.1: Two closely related fields

	Industrial engineering	Manufacturing engineering
Central question	How should the whole system be designed and run?	How should this product be made?
Typical decisions	Layout, staffing, scheduling, quality systems, supply chains	Process selection, tooling, machine programming, automation
Example tools	Process maps, simulation, statistics, optimization	CAD/CAM, CNC programming, process planning
Works in	Factories, hospitals, logistics, finance, government	Factories, suppliers, equipment builders

1.2 Where IMEs work

Because every organization runs on processes, IMEs work almost everywhere:

• Manufacturing. Agricultural equipment, aerospace, electronics, food processing, and medical devices.
• Healthcare. Reducing patient wait times, scheduling operating rooms, and preventing medication errors.
• Logistics and e-commerce. Designing warehouses, routing delivery fleets, and managing inventory.
• Service and government. Banks, airlines, theme parks, and public agencies all use IEs to improve service.

Career spotlight

Industrial engineers by the numbers

According to the U.S. Bureau of Labor Statistics, industrial engineers held about 365,100 jobs in 2025 and earned a median annual wage of $102,440. Employment is projected to grow 12 percent from 2025 to 2035, much faster than the average for all occupations (U.S. Bureau of Labor Statistics, 2026).

Source: U.S. Bureau of Labor Statistics, Occupational Outlook Handbook

1.3 How IMEs think: measure, model, improve

When an IME looks at a process, a few questions come first:

• How much does the system produce per hour? This is its throughput.
• How long does each step take? This is its cycle time.
• Which step limits the whole system? That step is the bottleneck.
• How busy is each resource? This is its utilization.

Worked example: the morning coffee rush

A campus coffee cart has three steps. Each customer is served by one worker at each step.

flowchart LR
  A([Customer<br/>arrives]) --> B[Take order<br/>30 s]
  B --> C[Make drink<br/>75 s]
  C --> D[Pay<br/>20 s]
  D --> E([Customer<br/>leaves])
  style C fill:#ffc82e,stroke:#0a5640,stroke-width:2px

Figure 1.1: Process flow at the campus coffee cart, with the time per customer at each step.

Each step can serve at most \(3600 / \text{time per customer}\) people per hour:

Table 1.2: Capacity of each step

Step	Time per customer	Max customers per hour
Take order	30 s	120
Make drink	75 s	48
Pay	20 s	180

The system can never go faster than its slowest step, so making drinks is the bottleneck and the cart serves at most 48 customers per hour (Table 1.2).

Now suppose 60 customers arrive per hour during the 8 a.m. rush. The takt time, the pace needed to keep up with demand, is

\[ \text{Takt time} = \frac{\text{available time}}{\text{demand}} = \frac{3600 \text{ s}}{60 \text{ customers}} = 60 \text{ s per customer}. \]

Drink-making takes 75 s, which is longer than the 60 s takt time, so the line keeps growing. If a second barista is added, drinks are finished every 37.5 s on average, and the cart’s capacity becomes \(3600 / 37.5 = 96\) customers per hour. Each barista is then busy

\[ \text{Utilization} = \frac{60 \times 37.5}{3600} = 62.5\% \text{ of the time.} \]

Find, measure, and relieve the bottleneck, then look for the next one. That habit is the core of the IE approach, and we’ll come back to it with lean in Week 8 and simulation in Week 10.

Hands-on notebook

IE by the numbers: throughput, bottlenecks, and takt time

View on GitHub · Download .ipynb

1.4 Your toolkit this semester

Along with learning about the profession, you’ll build the computer skills engineers use daily:

• Spreadsheets and Python to calculate, analyze, and manage data (Weeks 11–12).
• Project planning tools such as a Gantt chart and the critical path (Week 13).
• Technical writing and presentations to communicate your results (Week 14).

In-class activity

Spot the system (10 minutes, pairs)

Pick a campus process you used this week, such as the dining center line, the bookstore checkout, or getting a parking permit.

1. List its inputs, steps, and outputs.
2. Estimate the time each step takes.
3. Which step do you think is the bottleneck? What is one change that would relieve it?

Be ready to share your process map with the class.

1.5 Key takeaways

• Industrial engineering designs and improves integrated systems of people, materials, information, equipment, and energy. Manufacturing engineering focuses on how products are made.
• IMEs work in nearly every sector: manufacturing, healthcare, logistics, service, and government.
• A system’s throughput is limited by its bottleneck. Improving any other step won’t increase output.
• Takt time connects the system to customer demand.

TipCheck your understanding

1. In one sentence, how does industrial engineering differ from mechanical engineering? Mechanical engineering designs machines and devices. Industrial engineering designs the systems (people, equipment, information, materials) those machines operate within.

2. A process has steps of 40 s, 55 s, and 35 s. What is the bottleneck and the maximum hourly throughput? The 55 s step. \(3600 / 55 \approx 65\) units per hour.

3. Demand is 80 units in a 4-hour shift. What is the takt time? \(4 \times 3600 / 80 = 180\) s per unit.

NoteKey terms in this chapter

• Additive manufacturing — Building parts layer by layer directly from a digital model; commonly called 3D printing.
• Automation — Using machines and control systems to perform tasks with reduced human intervention.
• Bottleneck — The resource or step with the least capacity relative to demand; it limits the throughput of the entire system.
• CNC — Computer numerical control; machine tools whose motions are directed by programmed instructions.
• Critical path — The longest sequence of dependent tasks in a project; any delay on it delays project completion.
• Cycle time — The time between completions of successive units at a workstation or process; sometimes used for the total time one unit spends in the process.
• Gantt chart — A bar chart that shows project tasks against a timeline, including start dates, durations, and dependencies.
• Inventory — Stock of materials, work-in-process, or finished goods held to buffer against uncertainty in supply and demand.
• Manufacturing engineering — The branch of engineering that plans, designs, and improves the processes, tooling, and equipment used to turn raw materials into finished products.
• Motion study — The analysis of the body motions used to perform a task in order to eliminate unnecessary motions and reduce effort, pioneered by Frank and Lillian Gilbreth.
• Scientific management — A management approach, associated with Frederick W. Taylor, that uses systematic observation and measurement to find better methods of work.
• System — A set of interacting components (people, machines, materials, information) organized to achieve a common purpose.
• Systems thinking — An approach that studies how the parts of a system interact and influence the whole, rather than optimizing parts in isolation.
• Takt time — The pace of production required to meet customer demand, equal to available working time divided by customer demand.
• Therblig — One of the elemental motions (such as search, grasp, transport, and hold) defined by the Gilbreths for analyzing manual work; the word is Gilbreth spelled nearly backward.
• Throughput — The rate at which a system produces good output, such as parts per hour or patients per day.
• Utilization — The fraction of available time a resource is actually busy, calculated as time used divided by time available.

1.6 Further reading

• Kanigel’s biography of Frederick Taylor tells the story of the birth of scientific management (Kanigel, 1997).
• The Gilbreths’ own account of motion study is Applied Motion Study (Gilbreth & Gilbreth, 1917).
• The Handbook of Industrial Engineering surveys the whole field (Salvendy, 2001).

Gilbreth, F. B., & Gilbreth, L. M. (1917). Applied motion study. Sturgis & Walton.

Hafner, K., & Mayer, J. (2023). This efficiency-obsessed psychologist (and mother of 11) revolutionized kitchen design. In Scientific American. https://www.scientificamerican.com/article/this-efficiency-obsessed-psychologist-and-mother-of-11-revolutionized-kitchen-design/

Institute of Industrial and Systems Engineers. (n.d.). Industrial and systems engineering body of knowledge. Retrieved October 12, 2026, from https://www.iise.org/Details.aspx?id=43631

Kanigel, R. (1997). The one best way: Frederick winslow taylor and the enigma of efficiency. Viking.

National Museum of American History. (n.d.). On time: Saving time: Lillian gilbreth’s kitchen. Retrieved October 12, 2026, from https://www.americanhistory.si.edu/ontime/saving/kitchen.html

Salvendy, G. (Ed.). (2001). Handbook of industrial engineering: Technology and operations management (3rd ed.). Wiley.

U.S. Bureau of Labor Statistics. (2026). Industrial engineers. Occupational Outlook Handbook. https://www.bls.gov/ooh/architecture-and-engineering/industrial-engineers.htm