Waste elimination and continuous improvement (kaizen)
Waste elimination and continuous improvement (kaizen) tests whether you can identify waste with evidence, choose a countermeasure, and improve the standard rather than run a one-off cleanup.
Core rules
- The classic seven wastes are transport, inventory, motion, waiting, overproduction, overprocessing, and defects; unused human potential is often added as an eighth. Overproduction is usually treated as the worst because it creates other wastes.
- Separate muda from mura (unevenness) and muri (overburden). A process that swings from idle to overtime has mura; asking people to absorb the swing is muri.
- Kaizen follows PDCA: define the problem and target, grasp the current condition, find root cause, test a countermeasure, check results, and update standard work. Small, frequent changes are normal; big events are not the only form.
- Use data and direct observation. A spaghetti diagram, time observation, or defect Pareto can make waste visible; opinions alone are weak evidence.
- Improve the process, not just the output. A countermeasure that relies on extra inspection may move the defect downstream.
Worked example
An assembler walks 120 steps per cycle, completes 40 cycles per shift, and works two shifts. Daily walking = 120 × 40 × 2 = 9,600 steps. At 2.5 feet per step, that is 24,000 feet, or about 4.5 miles. Relocating a rack removes 30 steps per cycle: 30 × 40 × 2 = 2,400 steps/day, or 6,000 feet, about 1.14 miles saved daily. The reasoning: calculate the waste in the unit that matters (steps and distance), then verify that the new layout does not create transport waste or safety risk elsewhere. Update the layout standard and audit it.
Traps
Do not list wastes without linking them to evidence. Do not call necessary inspection waste without checking customer or regulatory requirements. Do not stop at operator error; that is rarely a root cause. Do not run kaizen without a baseline and a standard to improve.
Key points
- Seven wastes plus unused talent; overproduction creates other wastes.
- Separate muda, mura, and muri.
- Kaizen is PDCA with baseline, root cause, countermeasure, and new standard.
- Use observation and data, not opinion.