02 - DMAIC

Session 2: DMAIC Problem Solving

Pat Hammett, Univ of Michigan 1

1

DMAIC Problem Solving Process

2

Topics

I. Identifying Six Sigma Project Opportunities

II. Six Sigma Problem Solving Method DMAIC Methodology

III. Case Study Mold Changeover Process



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I. Identifying Six Sigma Project Opportunities

Start with your customer! External one who pays the bills Internal (Next Process Customer) next process that receives work

where possible, focus on Core Customers

External Customer Driven Projects Reactive to customer concerns / complaints (find & fix) Proactive to customer desires (strategic projects)

Internal Pain Projects Internal processing projects resulting from poor product-service

design or poor processing performance Value Stream Mapping (Flow-Variation Concerns)

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Six Sigma Project Examples

Manufacturing Operations Project Examples Conformance to customer use/ specifications (warranty reduction, customer satisfaction

projects) Conformance to internal product specifications (rework and scrap) Operational efficiency (processing time, material usage, equipment and facility usage)

Business Operations/ Transactional Project Examples Call Centers (response/ resolution time) Customer Ordering Systems (order time to delivery, order accuracy) Management Reporting (time/cost to prepare management reports) Design Process (CAD Release Errors, Drawing Completion Time) Customer complaints (call center, service center, etc.) Internal Business Processes (payroll systems, mail systems, accounting systems, working

capital improvement) Order System Processing (internal processing time/errors) Application Processing (internal approval process) IT Systems (information flow, complaints) Human Resource Management (staffing, training, benefits analysis) Retail Services (wait time, customer satisfaction) Hospital Systems (patient flow, operational efficiency, wait time)



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II. Six Sigma DMAIC Methodology

We often find it useful to utilize a generic process to successfully execute continuous improvement projects

Some commonly used Problem-Solving Processes: Six Sigma: Define Measure Analyze Improve Control TQM: PDCA ~ Plan Do Check Act Red X Strategy Engineering Method A3 Problem Solving Process, etc.

All of these have been applied successfully (and unsuccessfully)

This course will focus on Six Sigma DMAIC!

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DMAIC Problem Solving Method

DMAIC (deh-MAY-ihk) Define identify improvement opportunity Measure measure current state of the process Analyze identify causes of variation/ defects Improve develop and implement solutions Control install controls to prevent future defects

Like many other methods, DMAIC provides a robust structure to problem solving



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DMAIC Roadmap (Tools & Methods)

Improve(implement solution)

Control(establish plan to

prevent reoccurrence)

Identify Projects (based on QCD) Project Charter High Level Process Map/

Value Stream Map

Assess Current State of Key Output Variable (graphical and numeric)

Data pattern Process Capability/DPMO Process Stability

Measurement Systems Analysis (MSA) Identify key input variables

Measure(current state of Y)

Implement recommendations from analysis studies. (e.g., establish controls, determine optimal Settings)

Develop new process flow Implement lean counter

measures (standardized work, visual control, poka yoke)

Verify findings and pilot

Establish Control Plan Verify Project

Analyze(find key Xs)

Qualitative Process Analysis Process Mapping Potential variation causes

(e.g., Cause-Effect Diagram) Quantitative Process Analysis

Using statistical methods to determine key Xs and their effect (relationship)(e.g., Pareto Drill Down Analysis, Regression, Hypothesis Tests)

Prioritize key input variables

Define(improvement opportunity)

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III. DMAIC Case Study Head Lamp Manufacturing

Mold Changeover Reduction

Adapted from project by Don Lynch



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Headlamp Value Stream Map Analysis(Can you identify some improvement opportunities?)

Bodies

Lens

CT 65 S..Uptime 89% C/O 30 M.FTT 92%

CT 120 S.Uptime 84% C/O 3.54 H.(budget 2.5 H)FTT 95%

CT 45 S..Uptime 92% C/O 20 M.FTT 89%

CT 60 SUptime 98% C/O 30 M.FTT 95%

1 Day

60 sec.

3 Day5 Day

120 sec.

5 Day

65/45 sec.

14 Day

245 sec.

Big CarPlastic.

Vacuum Metal

I

I

I I

I

I

_5_/wk

Molding

Assembly

Coating

MPL6 week

Daily

6 week

Weekly

Weekly

Weekly

Weekly/Daily

Raw Matl Ship~14 days

~Value-add time~245 seconds

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Problem Background

Problem Background: Injection molding department is a bottle neck in head lamp assembly. A major issue is production losses due to excessive total changeover time both length of changeover and number of changeovers.

Current Performance Information: -Average Mold changeover=3.54 hours (historical data)

Budget Time < 2.5 hours - 3 changeovers/week per machine on average * 34 machines - Total lost production= 100 hours per week

Defect Definition:Any changeover taking more than the budgeted 2.5 hours

Question: Is this a product improvement orbusiness process improvement project?



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Define Phase Define improvement opportunity

Problem Statement Description of problem. Time period of problem. Magnitude of the problem and its impact on business performance,

in $$ if possible. Project Priority may include a Pareto Chart or other analysis to

justify why project has been selected over other opportunities.

Identify project improvement goal Goals should be SMART

Specific, Measurable, Attainable, Relevant, Time Bound

Identify project scope Should be able to complete project in 4-6 months

Usually summarize the above in a Project Charter

D M A I C

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Sample Project Charter Form Project Charter Template

Project Charter Template

Project Information ResourcesProject #: Project Leader:Project Name: Mold Changeover Reduction Black Belt: C. KramerProject Start Date: Champion:Project End Date: Process Owner: A. Vandolay

Problem Statement:

Goal Statement:

Project Scope

Excessive number of mold changes and mold changeover time per change resulting in excess labor hours vs. budget, scheduling problems, excess inventory, etc. This has been a chronic problem and is costing over $150K/year.

Team Members:

Eliminate mold change-overs taking longer than 2.5 hours.

Focus on reducing the number of changeovers and time per changeover for the 34 mold machines in the headlamp lens molding department.

W. Neuman, G. Constanze, E. Benes, B. Sakamana, T. Whatley



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Projected Savings(selling the project business case)

Is this project worth pursuing as a Six Sigma project?

D M A I C

Item Value

Actual Changeovers/Week 102Budgeted Changeovers/Week 60Actual Hours/Changeover 3.5Budget Hours/Changeover 2.5Weeks per year 47Total DL Rate 34.47

Lost Annual Hours (excess changeover time) $165,249Lost Annual Hours (excess # of mold changes) $170,109

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Measure Phase

Observe the Process First! (talk to the operators involved)

Map the Process of interest

Establish the Current State (baseline performance level). Key Tasks: Assess process stability and data patterns

1.Time Order (use run chart or statistical process control chart) Is problem sporadic (special cause) or chronic (consistent)?

2.Non-time order (use histogram or box plot) Is problem related to high variation, mean off target, or both?

Assess process capability (as DPM/DPMO*, Yield, Cp/Cpk) Mold Case: 80% of changeovers take longer than 3.5 hours

Assess measurement system capability

D M A I C*DPM = Defects per million; DPMO = Defects per million opportunity



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Dept. 682

Put machinein manual

Disconnect material feed

lines & run out material

Turn off mold heaters

Lower Mokon temp

Turn off power to injection

units

Disconnect water, air, hydraulic,

electrical lines

Remove mold Repair? Take mold to tool room

Yes

Return mold to rack in dept.

No

Get new mold from rack (or

tool room)

Install new mold

Reconnect water, air, hydraulic,

electrical lines

Turn on mold heater

Set Mokon Temp

Hook up material lines on mezzanine

Verify Program Settings

Start production

Quality Part?

Continue Production.

Inform Supervisor

Yes

Make Adjustments

No

D M A I C

Process Map Changeover

Process

Baseline -- current changeover process

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Sporadic vs. Chronic Problems

Sporadic Problems exist when unexpected changes in normal process operations occur (special cause variation) Typical Solution:

Chronic Problems exist when processes normally operate at an unacceptable level of common cause variation Typical Solution:

time

Consistent, but bad.

time

Y

Y



17D M A I C

Process Stability (Predictability over Time)

Comments Data in time order using a statistical process control chart (or run chart) Initial hypothesis -- only a few molds were causing problem (sporadic)Do these data support this hypothesis Or, is this problem chronic?

Individuals Chart

-0.070

3.542

7.153

-1.0

1.0

3.0

5.0

7.0

1 16 31 46 61 76 91 106 121 136 151 166 181 196 211 226 241 256 271 286 301

Subgroup

Indi

vidu

al V

alue

ControlLimit

18D M A I C

Process Distribution/Capability --Mold Changeover Time

Current State: average changeover time is 3.5 hours with a standard deviation of 1.1 (estimated DPM: ~817K)

Is distribution Normal (Bell-Shaped)? Mean and/or variation problem?

IMPLICATIONS?

Average StDev Yield3.5 1.1 18%

Individuals Chart

-0.070

3.542

7.153

-1.0

1.0

3.0

5.0

7.0

1 16 31 46 61 76 91 106 121 136 151 166 181 196 211 226 241 256 271 286 301

Subgroup

Indi

vidu

al V

alue

Histogram Changeover Time



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-0.05 0.00 0.05 0.10

Dif f erences

Boxplot of Differences(with Ho and 95% t-confidence interval for the mean)

[ ]X_

Ho

Measurement System Validation

Measurement system was evaluated by sampling 30 changeovers and comparing system results to actual timed results

D M A I C

Paired T-Test and CI: Computer, SamplingPaired T for Computer - Sampling

N Mean StDevComputer 30 3.772 1.367Sampling 30 3.766 1.358Difference 30 0.00633 0.03211

P-Value = 0.289

Is there a significant difference?

Why is this important to verify?

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Analyze Phase

Identify sources of variation / causes of defects or nonconformities

Identify the vital few key process input variables that affect key outputs -- Find the knobs

Use simple analysis tools first; apply complex tools as necessary. Be careful of too much data

Two Phase Approach Qualitative Analysis identify potential causes Quantitative Analysis perform statistical data analysis to

identify key X factors, robust ranges for key X variables, etc.

D M A I C



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Qualitative Analysis: Cause-Effect Diagram Example

Inefficient Changeovers

Maintenance avail.

Hose installation

Mold availability

Program set-up

PMEA availability

Knockout pins

Travel time

Mokon leaks

Mokon heating

Mokon malfunctions

Pick offs

Dryer

Hot runners

Bad fittings

No central storage

No standardization

Material change

PMEA training

Procedure

Mold cart

Lack of floor space

Mold racks

Excess dunnage

Man

Machines

Materials

Methods

Measurements

Environment

Dedidated, Efficient Changeovers

D M A I C

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Quantitative Analysis:Factors to Investigate

Factors or Variables to Study Differences by Individual Mold (Mold ID) Shift-Shift Differences Specific changeover tasks

Given data pattern identified in current state analysis, which of these are least likely?

D M A I C



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Analyze PhaseMultiple Box Plot: Stratification Analysis

Findings: Changeover not dependent on individual mold ID No statistically significant difference (based on mean test p-value) Note: line in center of box is median time by mold ID

Box Length50% of

Setups by ID

One Way ANOVAp-value 0.859

D M A I C

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Analysis by Shift

Findings: No difference

Implication?

Stratification Analysis by Shift

D M A I C

Analysis of Variance Time by SHIFTSource DF SS MS F SHIFT 2 1.14 0.57 0.29Error 120 234.26 1.95Total 122 235.40

p-value 0.747



25D M A I C

Others

Other w

ait t im

e for m

old

Wait t

ime fo

r main

tenanc

e servi

Verify

sett ing

s, prod

uce par

ts

Install

mold

Heat ing

proce

ss

Wait t

ime fo

r cart

985.6152.0190.0196.0200.0490.0580.035.3 5.4 6.8 7.0 7.217.520.8

100.0 64.7 59.3 52.5 45.5 38.3 20.8

2000

1000

0

100

80

60

40

20

0

DefectCount

PercentCum %

Perc

ent

Coun

t

PARETO OF TOP TIMED TASKS_ QUICK MOLD SETS

Top two factors:

Waiting time for carts - 21%

Heating process - 18%

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Analyze Phase

D M A I C

Top two causal factors (waiting for changeover cart and heating process) accounted for ~40% of total time or an average of 1.3 hours per changeover

Of the setup tasks, ~half of the actions could be completed with prior mold still running (external)

Other actions (and almost half of the average total time) required mold to be down when performing



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Improve Phase Improve phase is also known as the DO phase

Purpose of the improve phase is to make changes to a process to reduce/eliminate: defects, time, and costs

Improve countermeasures often have a dual purpose: Identify a better way (operating conditions) Identify a better system to maintain the better way (control)

D M A I C

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Some Common Improve Phase Types of Countermeasures

Implement one or several of the following actions to improve performance of key Y metric1. Improve Training and Empowerment2. Implement New Standardized Work Practice3. Redesign/Improve Process Flow

Batch Reduction or Elimination Change Process Layout (e.g., Cellular Teaming Concept)

4. Change (Optimize) a Process Input or Setting(s)5. Implement Quality at the Source 6. Install Mistake Proofing Device (Poka-Yoke)7. Install New Process Monitoring Systems

Visual Controls & Management to quickly identify defects Implement new data collection system

D M A I C



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Recommendations - Case Study

Implement Recommendations from Case Study

Case Study: Improvements completed in 3 phases Phase I Address top two: heating process and wait for cart

Scheduling of mold changes was changed to coincide with breaks Time for heating was hypothesized to go from 0.62 to 0.12 hours

Optimum number of carts calculated and additional cart was purchased Time waiting for carts was hypothesized to go to zero

Phase 2 Take more actions external to mold changeover time

Phase 3 Streamline internal actions

D M A I C

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Improve Phase - Verification

D M A I C

reduction over time by phase

Did phase 3 have a significant impact?

0

1

2

3

4

5

6

7

Tota

l

Boxplot of Changeover Time

(means are indicated by solid circles)

Base Phase I Phase II Phase III



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Verification Process Capability

Ran changeovers with new process across all molds Then, calculated Actual Savings: ~$200K

Average StDev YieldOriginal 3.5 1.1 18%Post Improve 1.4 0.5 98%

D M A I C

32

Control Phase

Control (and Verification) Phase install mechanisms or processes that prevent the re-occurrence of problems

Add audit to ensure compliance to standard operating procedures Add audit/control plan for suppliers. Install poka-yoke devices to identify defects/errors as they occur (e.g.,

automatic error proofing system) Install new process monitoring system/ IT system

Control phase involves the development, documentation, and implementation of a process control plan. Advanced Product Quality Plan (APQP) Guidelines (used by Auto Industry) ISO 9000 Guidelines

Effectiveness of control plan must be verified through long term study

D M A I C



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Control Phase - Case Study

D M A I C

Case Study Examples: Phase 1 Address the top factors (cart and heat process)

Purchase and receipt of additional changeover cart Change mold changeover process to heat during lunch when

possible (new standardized work practice) Process monitoring chart of changeover time

Phase 2 Take external actions outside of mold changeover Assignment of new labor standards for changeover team Change control plan/standardize work for mold changeover process

to convert external actions to occur outside of press Instruction of team to new process

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Project Viewed in Hindsight

Hmm, these project solutions seem obvious!

Recall, initial team beliefs

Follow Up: Why dont people just follow standardized work in the first place?



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Key Case Study Takeaways

Importance of characterizing a problem with data Evaluate if Mean and/or Variation Problem Assess if Sporadic or Chronic Problem

Analysis (Avoid Fatal Leap from Problem Solution) Importance of Systematic Problem Solving Decomposing Overall Variation into Sources Statistical & Practical Significance

Improve Phase Dual Purpose Improve and Control Let the data drive the solution

DMAIC with an R Replicate solutions to other problems

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Key Learning Items

Understand DMAIC Process DEFINE-MEASURE-ANALYZE-IMPROVE-CONTROL Understand key tasks/objectives of each phase

Note: cover in more detail throughout the course

Create a project charter Problem Statement

Description of problem, Time period of problem, and Magnitude of the problem and its impact on business performance, in $$ if possible

Stakeholders, Goal, and Scope

Understand difference between sporadic and chronic problem

02 - DMAIC

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