What's Six Sigma?

What is Six Sigma?

• A data-driven methodology to improve processes by reducing defects and variability.

• Goal: Achieve near-perfect quality with 3.4 defects per million opportunities (DPMO).

• Focuses on process improvement, efficiency, and customer satisfaction.

Key Principles:

1. Customer Focus – Understand and meet customer needs.

2. Data-Driven Decisions – Use facts, not guesses.

3. Process Improvement – Identify root causes of problems.

4. Proactive Management – Prevent issues before they happen.

5. Team Collaboration – Involve cross-functional teams.

6. Continuous Improvement – Always look for ways to do better.

DMAIC Framework (for existing processes):

• Define: Identify the problem and project goals.

• Measure: Collect data to understand current performance.

• Analyze: Find root causes of issues.

• Improve: Develop and implement solutions.

• Control: Maintain improvements over time.

Real-Life Examples:

• Manufacturing: Reducing defects in car parts production.

• Healthcare: Minimizing medication errors in hospitals.

• Banking: Reducing errors in loan processing times.

• Retail: Improving supply chain efficiency to reduce stockouts.

Common Six Sigma Tools

1. Process Mapping: Visualizes process flow to identify bottlenecks.

2. Fishbone Diagram (Ishikawa): Finds root causes of problems.

3. Pareto Chart: Focuses on the most critical issues (80/20 rule).

4. Control Charts: Monitors process stability over time.

5. FMEA (Failure Modes and Effects Analysis): Identifies potential failures and their impact.

6. Histogram: Shows data distribution to spot trends.

7. 5 Whys: Identifies the root cause by asking “Why?” repeatedly.

8. Cause & Effect Matrix: Links causes to their effects based on importance.

9. Value Stream Mapping: Highlights value-added and non-value-added steps.

10. SIPOC Diagram: Defines Suppliers, Inputs, Process, Outputs, Customers.

Tags:

#SixSigma

#ContinuousImprovement

#Waste

#Lean

📊 Sample of a Cause & Effect Matrix (C&E Matrix)

Scenario:

A restaurant is receiving customer complaints about slow service. The goal is to prioritize the process factors that most impact customer satisfaction.

Step 1: Identify Key Customer Requirements (CTQs)

• CTQs (Critical to Quality):

  1. Quick Service

  2. Accurate Orders

  3. Friendly Staff

  4. Food Quality

Step 2: List Process Inputs (Causes)

• Causes (Process Factors):

  
  

  A) Staff Training

  
  

  B) Order Taking Process

  
  

  C) Kitchen Workflow

  
  

  D) Inventory Management

  
  

  E) Communication Between Staff

Step 3: Assign Importance Ratings

• Rate CTQs on importance to the customer (1 = Low, 5 = High).

• Rate how strongly each cause affects the CTQ (0 = No impact, 1 = Low, 3 = Medium, 9 = High).

Cause & Effect Matrix

Process Causes	Quick Service (5)	Accurate Orders (4)	Friendly Staff (3)	Food Quality (5)	Total Score
A) Staff Training	3 × 5 = 15	9 × 4 = 36	9 × 3 = 27	3 × 5 = 15	93
B) Order Taking Process	9 × 5 = 45	9 × 4 = 36	3 × 3 = 9	1 × 5 = 5	95
C) Kitchen Workflow	9 × 5 = 45	3 × 4 = 12	1 × 3 = 3	9 × 5 = 45	105
D) Inventory Management	3 × 5 = 15	1 × 4 = 4	0 × 3 = 0	9 × 5 = 45	64
E) Staff Communication	9 × 5 = 45	9 × 4 = 36	3 × 3 = 9	3 × 5 = 15	105

✅ Analysis & Interpretation:

• Highest Scores:

  • C) Kitchen Workflow = 105

  • E) Staff Communication = 105

• These factors have the greatest impact on customer satisfaction and should be prioritized for improvement.

🎯 Next Steps:

1. Focus on optimizing kitchen workflow (e.g., streamline food prep processes).

2. Enhance staff communication (e.g., implement better coordination tools or training).

3. Reassess after improvements to measure impact on customer satisfaction.

Sample of FMEA (Failure Modes and Effects Analysis)

Let’s consider an example of a coffee machine manufacturing process to identify potential failures.

📋 FMEA Table for Coffee Machine Assembly

Process Step	Potential Failure Mode	Potential Effect of Failure	Severity (1-10)	Potential Causes	Occurrence (1-10)	Current Controls	Detection (1-10)	RPN (Risk Priority Number)	Recommended Actions
Assemble Heating Unit	Loose electrical connection	Machine won’t heat properly	8	Poor soldering technique	6	Visual inspection	5	240	Improve soldering training; add automated testing
Install Water Pump	Pump leakage	Water damage to internal parts	9	Faulty pump seal	4	Leak test after assembly	4	144	Use higher-quality seals; increase leak tests
Attach Control Panel	Unresponsive buttons	User cannot operate machine	7	Poor electrical contact	5	Manual function check	6	210	Automate functional tests; enhance inspection
Final Assembly	Loose screws	Machine parts fall apart	6	Inconsistent torque application	7	Random quality checks	4	168	Use torque wrenches with sensors; 100% checks
Packaging	Inadequate padding	Product damage during shipping	5	Incorrect packaging materials used	3	Final visual check before shipping	6	90	Update packaging guidelines; regular audits

⚡ Key Metrics Explained:

• Severity (S): Impact of the failure on the customer (1 = low, 10 = catastrophic).

• Occurrence (O): Likelihood of the failure happening (1 = rare, 10 = frequent).

• Detection (D): Ability to detect the failure before it reaches the customer (1 = easy to detect, 10 = hard to detect).

• RPN (Risk Priority Number): RPN = S × O × D (used to prioritize issues).

✅ How to Use This FMEA:

1. Identify High-RPN Areas: Focus on risks with the highest RPN (e.g., Loose electrical connection with RPN 240).

2. Take Corrective Actions: Implement the recommended actions to reduce the severity, occurrence, or improve detection.

3. Review & Update: After actions are taken, reassess RPN to confirm risk has been reduced.

🐟 Sample of a Fishbone Diagram (Ishikawa Diagram)

Scenario:

A retail store is facing an issue with declining customer satisfaction. The goal is to identify the root causes.

Main Problem:

🎯 Declining Customer Satisfaction

Categories (6 Ms):

• Man (People)

• Machine (Technology/Equipment)

• Method (Processes/Procedures)

• Material (Products/Resources)

• Measurement (Data/Feedback)

• Mother Nature (Environment)

Fishbone Diagram Structure: