UpSkill Sprint Consulting
  • Lean Six Sigma
  • Beginner
  • 10 min
  • Interactive

DMAIC in 10 Minutes

DMAIC is the five-step roadmap Lean Six Sigma teams use to fix a problem in a process that already exists. One question per step, answered in order.

One project, start to finish

A DMAIC project in one chart

A pipe-cutting line re-cuts too many pipes. Follow the bad-cut rate through the five phases. (A made-up example.)

The whole project in one chart Weekly percentage of out-of-tolerance cuts on Line 2 across the five DMAIC phases. About 6% in Define, a 5.8% baseline in Measure and Analyze, 1.6% during the Improve pilot, and holding at 1.7% in Control, under the 2% goal. D M A I C 0% 2% 4% 6% Goal 2% Baseline 5.8% Pilot 1.6% Holding at 1.7% Weeks 1 to 25
Weekly bad cutsGoalShaded bands: D, M, A, I, C phases.

Define: agree on the problem

What's the problem, and what does success look like?

Tools

  • Project charter
  • SIPOC
  • Voice of the customer

You finish with

A signed-off project charter

Project charter: Line 2 re-cuts

Problem
6% of pipes re-cut
Goal
2% or less in 4 months
Scope
Line 2, both shifts
Out of scope
The upstream mill
One page that the team and sponsor agree on.

Measure: trust the data first

How big is the problem today, and can we trust our measurements?

Tools

You finish with

A baseline you trust: 5.8% bad cuts

One pipe, measured ten times Ten readings of the same pipe. The hand tape spreads from minus 5 to plus 6 millimetres, wider than the plus or minus 5 millimetre tolerance, so it cannot tell good pipes from bad. The length gauge stays within 1 millimetre. Tolerance ±5 mm Hand tape Length gauge -6 -3 0 +3 +6 mm from nominal length
The tape can't tell good pipes from bad, so the team switches to the gauge before collecting the baseline.

Analyze: find the root causes

Which causes really drive the problem?

Tools

You finish with

Root causes proven with data

Pareto chart of bad cuts by cause 232 bad cuts in the baseline. Blade wear caused 104 and stop-block setup 70: together 75% of all bad cuts. Material bow, measuring and other causes make up the rest. 104 Blade wear 70 Stop-block setup 30 Material bow 16 Measuring 12 Other 0% 50% 100% 75% from 2 causes Bad cuts by cause (bars) and cumulative % (line)
Two causes, blade wear and stop-block setup, make 75% of the bad cuts. Fix those first.

Improve: fix the causes, then prove it

Which fix removes the root causes, and does it work?

Tools

  • Solution matrix
  • FMEA
  • Pilot run
  • DOE

You finish with

A piloted fix that beats the baseline

Baseline versus pilot Out-of-tolerance cuts fell from a 5.8% baseline to 1.6% on the pilot shift, beating the 2% goal. Baseline 5.8% Pilot 1.6% Goal 2%
Pilot on one shift: a setup checklist with a reference gauge, plus a fixed blade-change schedule.

Control: make the gains stick

How do we stop the process sliding back?

Tools

You finish with

A control plan handed to the process owner

Control chart of weekly bad cuts Twelve weeks after the change, every point sits between the lower limit of 0.8% and the upper limit of 2.6%, around a centre line of 1.7%. No signals, so the gains are holding. UCL 2.6% CL 1.7% LCL 0.8% Weeks after rollout
Every week inside the limits: the gains are holding at 1.7%.

Tollgates. Each phase ends with a short sponsor review before the next one starts.

Try it

Which phase? Sort six real project activities

Pick the phase for each activity. One try each.

Interactive
1. Write a problem statement and agree the project scope with the sponsor.

2. Run a Gage R&R study to check that inspectors measure the same part the same way.

3. Use a Pareto chart and a hypothesis test to check which suspected causes really matter.

4. Pilot a new setup checklist on one shift and compare the results with the baseline.

5. Give the process owner a control chart and a plan for what to do when it signals.

6. Collect four weeks of data to find out how often parts fail today.

0 of 6 sorted

Choosing the right tool

Is DMAIC the right tool? Follow the arrows

  1. Does the process already exist?

    NoDesign it new with a design approach such as DMADV.

    Yes: next question

  2. Do you already know the cause and the fix?

    YesJust do it. No project needed.

    No: next question

  3. Are customers being hurt right now?

    YesContain it first, then start DMAIC.

    No: next question

  4. OtherwiseUse DMAIC.

4 ways DMAIC projects go wrong

  • Jumping to a fixSkipping Measure and Analyze treats symptoms.
  • Trusting bad dataCheck the gauge before the baseline.
  • Scoping too bigOne line, one defect, one goal.
  • Skipping ControlNo owner and no plan, and the gains fade.

Exam tip. ASQ's Six Sigma Green Belt and Black Belt bodies of knowledge are organized largely around the DMAIC phases. Expect "which phase does this tool belong to?" questions.

Knowledge check

Check your understanding

Comprehension quiz

Pick the strongest answer, then submit. Explanations appear after you submit.

1. What do the letters DMAIC stand for?
2. A team checks that its inspection gauge gives repeatable readings before collecting baseline data. Which phase is this?
3. Why does Analyze come before Improve?
4. Which output marks the end of the Control phase?
5. In which situation is DMAIC the wrong tool?

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