Overview

Mechanical engineers build the machine. Industrial Engineers build the factory that makes the machine. They are the engineers of efficiency. Their goal is to save time, money, and effort. They make things faster, cheaper, and better.

Core Idea

The core idea is Optimization. Finding the “Best” way to do something.

  • “How can we board this plane in 10 minutes instead of 20?”
  • “How can we reduce the wait time in the ER?”

Formal Definition

The optimization of complex processes, systems, or organizations. Key Concepts: Supply Chain, Operations Research, Ergonomics.

Intuition

  • The Checkout Line: Why is the line always long? An Industrial Engineer analyzes the arrival rate of customers and the service rate of cashiers to calculate the optimal number of open lanes (Queuing Theory).
  • McDonald’s: The kitchen is a masterpiece of industrial engineering. Everything is placed exactly where it needs to be to minimize movement and maximize speed.

Examples

  • Ford’s Assembly Line: Henry Ford didn’t invent the car; he invented the process to make cars cheap. That is industrial engineering.
  • Toyota Production System (Lean): Eliminating “Muda” (Waste). If a part sits on a shelf for a week, that is waste. Just-in-Time manufacturing.
  • UPS: Their trucks don’t turn left (because left turns waste gas and time waiting for traffic). This algorithm saves millions of dollars.

Common Misconceptions

  • It’s just common sense: It’s actually complex math (Linear Programming, Statistics).
  • It treats people like robots: Taylorism (Scientific Management) was criticized for this. Modern IE includes “Human Factors” (Ergonomics) to make work safer and easier for humans.
  • Six Sigma: A method to reduce defects. (99.99966% perfection).
  • Logistics: Getting the right box to the right door at the right time.

Applications

  • Hospitals: Reducing surgery errors and patient wait times.

Criticism / Limitations

  • Fragility: Just-in-Time is efficient, but if one ship gets stuck in the Suez Canal, the whole world runs out of toilet paper. Efficiency can reduce resilience.

Further Reading

  • Goldratt, Eliyahu. The Goal. (A novel about industrial engineering).