=================================================================================
DMAIC (Define, Measure, Analyze, Improve, Control) is a data-driven problem solving method for identifying and addressing inefficiencies in a process, improving its outputs, and making these improvements more predictable.
The primary methodology of Six Sigma program is the application of DMAIC. Six Sigma DMAIC is used to solve quality problems of greater complexity and with unknown root causes with the five-phase cycle:
i) Define. This is the first DMAIC stage which focuses on analysis of customer identification, feedback, and requirements along with forming the project stakeholder team [1]. The project team looks at critical to quality (CTQ) and cost of quality (COQ) improvement projects that need to be addressed. It is very critical to define an accurate problem statement
along with the scope to ensure that the Six Sigma project team will invest all the time, skills, and
resources in the right direction.
ii) Measure. This is the data collection phase where types of data, measurement scales, and
sampling and collection methods are evaluated. During the measure and analyze phases of a project, data are collected from the processes to understand the baseline performance and for validation of causes. [2,3]
iii) Analyze. Measure and model relationships between variables, hypothesis testing, root
cause analysis using cause and effect analysis tools such as fishbone/Ishikawa diagrams, 8D
methodology, and 5 Whys analysis. [2,3]
iv) Improve. Post root cause analysis, this phase tries to understand optimum levels of factors responsible for causing the problem via design of experiments (DOE), giving insights to determine corrective and preventative actions. This stage involves lean strategies such as the
Kaizen Blitz, poka-yoke (mistake-proofing), cycle time reduction, etc. [3-5]
v) Control. Primary objective in this last phase is to maintain and sustain control over the process and suggest improvement activities to minimize variation and defects. Statistical process control (SPC), total productive maintenance (TPM), and control plan development are some
key tools used in the control phase. [6]
Table 4202a lists the DMAIC steps and tools usage.
Table 4202a. DMAIC steps and tools usage. [7]
| Step |
Specific tasks |
Tools and techniques used |
| Define |
Identify, evaluate and select projects
Analyze voice of customers (VOC)
Identify improvement issues
Organize project team
Set-up improvement goal
Estimate financial benefit
Select and launch the team
|
Customer complaint analysis
Cost of poor quality (COPQ)
Brainstorming
Run charts, control charts
Benchmarking |
| Measure |
Measure the size of the problem
Document the process
Identify key
customer requirements
Document potential failure modes and effects
Determine key product characteristics and
process parameters
Theorize on the cause or determinants of performance
Map process and identify inputs and
outputs
Establish measurement system for
inputs and outputs
Understand the existing capability of
process
|
Process map (SIPOC)
Cause and effect matrix
Gauge R&R
Control charts
Process capability analysis
Failure models and effects
analysis (FMEA) |
| Analyze |
Plan for data collection
Analyse the data and establish and confirm the "vital few" determinants of performance
Identify sources of variation in
process
Identify potential critical inputs
Discover the root causes
Determine tools used in the
improvement step
|
Cause-and-effect diagram
Pareto diagram
Scatter diagram
Brainstorming
Analysis of variance (ANOVA) |
| Improve |
Create the strategic actions to
eliminate the root causes
Conduct improvement actions
Use experiments
Optimize critical inputs and the process
Design and carry out experiments to determine the mathematical cause-effect relationships
|
Design of experiment (DOE)
Quality function deployment
(QFD)
Process capability analysis
Control charts |
| Control |
Standardize the process
Maintain critical inputs in the
optimal area
Verify long-term capability
Evaluate the results of improvement
projects
Design controls
Make improvements
Implement and monitor
|
Standard operation procedure
Process capability analysis
Fool-proofing (Poka Yoke)
Run charts
Failure models and effects
analysis (FMEA) |
Figure 4202. Improved DMAICL cycle. [7] |
Table 4202b. Comparison between DMAIC, A3 and 8D. |
| |
DMAIC |
A3 |
8D |
| Plan |
Define |
Clarify the problem |
D0: Prepare and plan for the 8D
D1: Create team and collect information
D2: Describe the problem |
| Measure |
Break down the problem |
| Set a target |
D3: Define containment actions |
Analyze
|
Analyze the root cause |
D4: Analyze the root cause |
| Develop contermeasures |
D5: Define possible corrective actions |
| Do |
Improve |
See countermeasures |
D6: Implement corrective actions |
Check
|
Control |
Evaluate results and processes |
D7: Define actions to avoid recurrence
D8. Congratulate your team |
| Act |
Standardize success |
============================================
[1] ISO/TS 16949:2009. Quality Management Systems. Geneva: ISO, (2008).
[2] Quality Council of Indiana. CSSBB Primer. West Terre Haute, Ind. Quality Council of
Indiana; Vol. 42010. 2014. pp. 125-134.
[3] George ML. Lean Six Sigma. New York: McGraw-Hill; 2002.
[4] Breyfogle III. Implementing Six Sigma. 2nd ed. New York: John Wiley & Sons; 2003.
[5] Nakajima S. Introduction to TPM: Total Productive Maintenance. Cambridge, MA:
Productivity Press; 1998.
[6] Wise S, Fair D. The Control Chart Dilemma. ASQ, Knoxville, Tennessee, USA: Quality
Progress; 1998.
[7] Tauseef Aized, Total Quality Management and Six Sigma, 2012.
|
