Lean Fundamentals and Principles
What the exam tests
This domain covers the foundations you will reuse in every other section: the customer definition of value, the five Lean principles, the TPS house, and the difference between value-adding work and waste. Expect questions that ask you to classify a situation, not just recite a definition.
Core rules and concepts
- Value is defined by the customer: what they will pay for, when they need it, at a price they accept.
- The five principles are specify value, identify the value stream, create flow, establish pull, and pursue perfection.
- TPS rests on just-in-time and jidoka, stabilized by heijunka, standard work, and kaizen. Respect for people is not a slogan; it is the operating assumption.
- Waste (muda) is activity that consumes resources without creating customer value. Mura is unevenness; muri is overburden. Removing muda without addressing mura and muri often moves the problem.
- Push schedules work to a forecast; pull authorizes work from downstream consumption.
Worked example
A cell has 480 minutes available and customer demand of 240 units per day, so takt time is 2.0 minutes per unit. Three steps have cycle times of 1.6, 2.3, and 1.9 minutes. The bottleneck at 2.3 minutes exceeds takt, so the cell cannot meet demand even though the average cycle time is 1.93 minutes. The reasoning: capacity is set by the constraint, not the average. Options are reduce the 2.3-minute step below 2.0, add a parallel resource, or move work to the 1.6-minute step. Adding WIP would hide the gap and increase lead time.
Traps that cost marks
Treating Lean as a cost-cutting toolbox; calling any non-work activity value-added; confusing takt time with cycle time; assuming automation is always the answer; and ignoring muri when a process is overloaded.