Six Sigma - Understanding basic concepts

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Six Sigma - Understanding basic concepts
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Business Relevance of 6s
Substitution
Improvement (in Qly, Cost, Del Serv.)
Govt. Policies
Competition
Maintenance (Old Products Services)
Customer
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Gap analysis Dos Needs
Quality
Supplier
Defect Free
Customer
Needs
Delivery
Dos
Cycle Time
Price
Cost
Gaps to be addressed continuously
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Six sigma Simple concept

• 6 s is a level of performance that reduces the
  defects in products services significantly
• A set of statistical tools that helps to measure,
  analyse, improve and control processes.
• A commitment to customers to achieve an
  acceptable level of performance
• Mind Set Tool Set Six s

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6 Sigma Theme

• Customer focussed
• Processes are key drivers
• Fact driven and Proactive for creativity
• Result oriented - demands financial analysis to
  verify gains

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6 Sigma Theme

• Voice of Customer (VOC) Specs decided by
  customers (Dependent variable, say Y)
• - Response time TAT Breakdowns Product
  performance, waiting time at ATM/counter etc.
• Voice of Process (VOP) Variability of a process
  Process variations cause defects (Independent
  variable, say x)

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6 Sigma Quality Theme
Six Sigma Quality
Hitting the Target (Centralise the Process)
Elimination of Process variability
Process should be with minimum variability and
on the target
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What does 6 Sigma do?
Statistical solution
Statistical problem
Real life problem
Y
y
y f(xi)
Real life solution
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6 Sigma Steps - RDMAIC
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6 Sigma Steps - RDMAIC

1. To identify the major business issues
2. To recognise key processes that need improvement
3. Areas that need break throughs

1. Identify critical to customer (CTC)
2. Drill down to CTQ (translating expectations to
   parameters)
3. Define specs, UL LL, Targets

Y f (xi)
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6 Sigma Steps - RDMAIC

• Tools generally used
• QFD Matrix
• Importance gain matrix

• Project selection criteria
• high gain
• low hanging fruits
• Urgency
• Efforts required

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6 Sigma Steps - RDMAIC

1. Define the key requirements to customer
2. Customers know their language
3. Listening to customers means understanding their
   needs.
4. Drill down the CTC

• Define step will deliver
• Project Chartering
• (Goal, Milestone, Roles)
• Process Mapping (SIPOC model)

• Customer say Engineers say..
• Long life 20,000 Hrs life
• Reliable 3000 MTBF
• Comfort cooling 24 1 Deg C

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6 Sigma Steps - RDMAIC

1. Input, Process and output measures are to be
   defined
2. Measure process stability
3. Measure repeatability and reproducability
4. Measure current process capability

Standard softwares are available to process the
data
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3 Sigma process
99.78
95.44
68.26
Upper Control Limit
Total surface area 100
Lower Control Limit
1?
1?
1?
1?
1?
1?
X
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Customer perceive and register the variance more
than average
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6 Sigma process (statistical vision)
Upper Spec.
Lower Spec.
6?
6?
X
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Defects vs Defectives
Defects Countable failures that are associated
with a single unit. A single unit can be
defective but may contain more than one defect.
Defectives Completed units that are classified
as bad or not meeting specs. Whole unit is said
to be of defective.
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Terminologies used
DPU DPU Defects / unit
DPMO
DPU x 1,000,000
DPMO
Opportunities per unit
Defects

x 1,000,000
Opportunities
Defects per million opportunities
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6 Sigma process (measures)
Sigma Defects per Million
(DPMO) 2 308,537 3 66,807
4 6,210 5 233 6 3.4
non-defective 69.1
93.32 99.379 99.9767 99.99966
24 6 0.6 0.023
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Example 1 52 defects, 250 AMC proposals, 4
defects opportunities / proposal DPMO (52)/
(2504) X 1000000 52,000 3.1
Sigma level
Traditional approach 5 applications were
rejected (contains 52 defects) 5/250 2
rejection
Example 2 99 defects, 750 products, 150
defects opportunities /product DPMO (99)/
(750150) X 1000000 880 4.65
Sigma level
Traditional approach 10 products were rejected
(contains 99 defects) 10/750 1.33 rejection
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Software (Minitab) outputs some screens..
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Software (Minitab) outputs some screens..
P gt 0.05 Data follows normal distribution
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Software (Minitab) outputs some screens..
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6 Sigma Steps - RDMAIC

1. Identify cause effect y f (x)
2. Use analytical tools to vital few
3. Short list causes that are vital few which can be
   taken to improve phase

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6 Sigma Steps - RDMAIC
Identify and formulate causes
Identify Opportunities
Quantify and verify causes

• process mapping
• FMEA
• QFD
• Process Capability
• Stratification
• Seven QC tools
• Why-why analysis
• Brainstorming

• Hypothesis tests
• DOE

• Identify success factor
• List of opportunities in vital few

Y f(x1, x2, x3, x4, x5,..xn) This s the
function that models and quantifies the
relationship between X Y
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6 Sigma Steps - RDMAIC

1. To find out vital causes (x)
2. Optimal value of causes
3. Verify optimal setting with set tolerances

DOE is one of the tools used to establish
relationship between inputs outputs
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6 Sigma Steps - RDMAIC

1. Measurement System validation for inputs
2. Process capability
3. Implementation of SPC Charts

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FMEA
FMEA is an analytical technique used by
designers, engineers and analysts to ensure that
all design or manufacturing or process failure
modes have been considered and are assessed with
a view of elimination.

• System FMEA
• Process FMEA
• Product/Design FMEA

What is a failure? A component or system not
meeting or not functioning as per design (Ex.
Break failure)
What is a failure mode? The manner in which a
component or a system failure occurs (Ex. leakage
of break oil )
What is an Effect? The impact or consequence of
failure (vehicle meeting accident)
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FMEA
Degree of chances that it gets detected before it
goes to customer

1. Severity of effect? (Scale 1-10)
2. Possibility of failure? (scale 1-10)
3. Possibility of detecting? (scale 1-10)

Severity of impact
Prob. of occurrence
RPN (Risk Priority Number)
Detectability
1. 8
4
2
64 (Max 1000, Min 1)
2. 4
9
216
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Work on high RPN Reduce severity, rarely
changes Reduce prob of occurrence (Have parallel
system, hand break) Improve detectability
(process, tests, reliability)
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QFD
Tool used priorities the areas to focus.
Correlation between Xs
H
M
L
X1
X2
X3
X4
X5
3
2
6
5
2
4
3
4
Customer Requirements
4
3
2
2
3
7
1
3
1
1
5
1
56
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57
Proj to focus
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DOE
Structured proactive process for finding
relationship between input and output
factors. Multiple input factors are considered
and controlled simultaneously to ensure that the
effect on the output is significant.

• Why DOE?
• To find out vital few Xs that influence the
  quality of Y
• To identify the best combination of values of Xs
  to get the optimal value of process performance

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Sigma level - Customer focus

0 Sell forget
1 Know what happens to sold products
2 Inspect before despatch (QC)
3 Inspect the process (Process monitoring)- QC
4 Control the process
5 Understand the process control it (SPC)
6 Re-engineer the process in line with customers expectation (RDMAIC)
7 Right product meeting expectations (RDMAIC)
8 Understand customer requirements design prod / service features defect free (Design for 6 s)
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Sigma level of different sectors
Tax advice
Prescription writing
Restaurant bill
Payroll processing
1000,000
Air Lines Baggage handling
100,000
10,000
Best in Class
Air Lines safety
1000
Defects in PPM
100
10
1
2
4
5
6
7
3
1
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Thank you