A full worked DMAIC case study on an injection-molding cell — baseline DPMO and sigma level, fishbone/5 Whys root cause analysis, the process change implemented, and a validated before/after defect-rate improvement with a control plan.
The project brief: an injection-molding cell producing a snap-fit plastic enclosure has run a persistent, never-formally-investigated scrap rate that operators had informally blamed on "bad resin." This module runs a complete Define–Measure–Analyze–Improve–Control cycle to establish a real baseline defect rate, find the actual root cause, implement a targeted fix, and validate the result.
This module walks the whole project the way a real Six Sigma practitioner would: a worked baseline DPMO and sigma-level calculation, a Pareto-prioritized fishbone/5 Whys root cause investigation, the specific process and preventive-maintenance change implemented, and a follow-up measurement showing the validated sigma-level improvement plus the control plan that sustains it. The full worked numbers, before/after metrics table, and finished DMAIC reasoning are part of the unlocked module below.