six sigma green belt project - by imran haq 23-11-2010

8/3/2019 Six Sigma Green Belt Project - By Imran Haq 23-11-2010

1/34

1 | P a g e

REDUCING REJECTION SCORE OF RFIS DURING

INSPECTION & TESTING PHASE AT PROJECT SITE

A Project of Six Sigma Green Belt

Prepared by:

Muhammad Imran Haq KhanSupervised by:

Iftikhar Ahmad (Black Belt/Green Belt)

Submission date:

November 23, 2010

Organized by:DAS Certification Pakistan

207, Main Street, I-10/3, Main Service Road (East) Industrial Area Islamabad-Pakistan

Ph: + 92 51 5829773, + 92 51 5829773, 4430120 Fax + 92 51 4430121,www.das.com.pk
http://www.das.com.pk/http://www.das.com.pk/http://www.das.com.pk/http://www.das.com.pk/


2/34

2 | P a g e

Table of Contents

Index Description Page

1 Introduction 3

1.1 Brief introduction to six sigma methodology 4

1.2 Introduction to the project 5

2 Define 6

2.1 Six Sigma Project charter 7

2.2 Process Mapping 9

2.2.1 Voice of Customer 10

2.3 Affinity Diagram 11

2.4 SIPOC Diagram 12

3 Measure 13

3.1 Six Sigma Level Calculation 14

3.1.1 Process Capability 15

3.2 Pareto Analysis diagram 16

3.3 RFI Table-Process Data 17

3.3.1 Flaws Identified During Inspection & Testing 18

4 Analyze 19

4.1 Cause & Effect Diagram For Rejection of RFI 20

4.2 RFI Table After Applying Improvement Steps 21

4.3 Fish Bone Diagram 22

4.4 Factors Affecting Rejection Of RFI 23

5 Improve 24

5.1 Co-Relation Of Different Factors 25

5.2 Improved Table Of RFI After Applying Improvement Steps 26

5.2.1 Types Of Defects 27

5.2.2 Process Capability Verification 28

5.3 Fish Bone Diagram For Inspection & Testing Flaws 29

5.4 Inspection & Testing Flaws Affecting Rejection Of RFI 30

6 Control 31

6.1 Rejection Chart (Simple Line Graph) 32

6.2 Process control Plan 33

Summary 34


3/34

3 | P a g e

1. INTRODUCTION


4/34

4 | P a g e

1.1 Brief Introduction to six sigma methodology

Six Sigmaseeks to improve the quality of process outputs by identifying and removingthe causes of defects (flaws) and minimizingvariabilityinmanufacturingprocesses. It uses aset of quality management methods, including statistical methods, and creates a specialinfrastructure of people within the organization ("Black Belts", "Green Belts", etc.) who are

experts in these methods. Each Six Sigma project carried out within an organization followsa defined sequence of steps and has quantified financial targets (cost reduction or profitincrease).

The term six sigmaoriginated from terminology associated with manufacturing, specificallyterms associated with statistical modelling of manufacturing processes. The maturity of amanufacturing process can be described by a sigma rating indicating its yield, or thepercentage of defect-free products it creates. A six-sigma process is one in which99.99966% of the products manufactured are statistically expected to be free of defects (3.4defects per million).

DMAIC

The DMAIC project methodology has five phases:

Definethe problem, the voice of the customer, and the project goals, specifically.

Measurekey aspects of the current process and collect relevant data.

Analyzethe data to investigate and verify cause-and-effect relationships. Determinewhat the relationships are, and attempt to ensure that all factors have beenconsidered. Seek out root cause of the defect under investigation.

Improveor optimize the current process based upon data analysis using techniques

such asdesign of experiments,poka yokeor mistake proofing, and standard work tocreate a new, future state process. Set up pilot runs to establishprocess capability.

Controlthe future state process to ensure that any deviations from target arecorrected before they result in defects. Implementcontrol systemssuch asstatisticalprocess control,production boards, andvisual workplaces, and continuously monitorthe process.
http://en.wikipedia.org/wiki/Statistical_dispersionhttp://en.wikipedia.org/wiki/Statistical_dispersionhttp://en.wikipedia.org/wiki/Statistical_dispersionhttp://en.wikipedia.org/wiki/Manufacturinghttp://en.wikipedia.org/wiki/Manufacturinghttp://en.wikipedia.org/wiki/Business_processhttp://en.wikipedia.org/wiki/Business_processhttp://en.wikipedia.org/wiki/Business_processhttp://en.wikipedia.org/wiki/Quality_managementhttp://en.wikipedia.org/wiki/Quality_managementhttp://en.wikipedia.org/wiki/Statisticshttp://en.wikipedia.org/wiki/Statisticshttp://en.wikipedia.org/wiki/Process_capabilityhttp://en.wikipedia.org/wiki/Process_capabilityhttp://en.wikipedia.org/wiki/Design_of_experimentshttp://en.wikipedia.org/wiki/Design_of_experimentshttp://en.wikipedia.org/wiki/Design_of_experimentshttp://en.wikipedia.org/wiki/Poka_yokehttp://en.wikipedia.org/wiki/Poka_yokehttp://en.wikipedia.org/wiki/Poka_yokehttp://en.wikipedia.org/wiki/Process_capabilityhttp://en.wikipedia.org/wiki/Process_capabilityhttp://en.wikipedia.org/wiki/Control_systemshttp://en.wikipedia.org/wiki/Control_systemshttp://en.wikipedia.org/wiki/Control_systemshttp://en.wikipedia.org/wiki/Statistical_process_controlhttp://en.wikipedia.org/wiki/Statistical_process_controlhttp://en.wikipedia.org/wiki/Statistical_process_controlhttp://en.wikipedia.org/wiki/Statistical_process_controlhttp://en.wikipedia.org/w/index.php?title=Production_boards&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Production_boards&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Production_boards&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Visual_workplaces&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Visual_workplaces&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Visual_workplaces&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Visual_workplaces&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Production_boards&action=edit&redlink=1http://en.wikipedia.org/wiki/Statistical_process_controlhttp://en.wikipedia.org/wiki/Statistical_process_controlhttp://en.wikipedia.org/wiki/Control_systemshttp://en.wikipedia.org/wiki/Process_capabilityhttp://en.wikipedia.org/wiki/Poka_yokehttp://en.wikipedia.org/wiki/Design_of_experimentshttp://en.wikipedia.org/wiki/Process_capabilityhttp://en.wikipedia.org/wiki/Statisticshttp://en.wikipedia.org/wiki/Quality_managementhttp://en.wikipedia.org/wiki/Business_processhttp://en.wikipedia.org/wiki/Manufacturinghttp://en.wikipedia.org/wiki/Statistical_dispersion


5/34

5 | P a g e

1.2 Introduction to project

I have chosen a project to find out the possible reasons for the rejection of the RFI and toimprove level of RFI (Request For Inspection) acceptance by reducing inspection flaws andreduction in cost of quality.

I got the data of 5 pressure vessels from the last year, manufactured in two different bays Aand B. All of the testing data disclose the real position of failure rate of RFI in the year 2009.In this green belt project I tried my level best to apply the suitable statistical tools toanalysis and improve product quality by decreasing the rejection rate. Complete studycarried out in the coming phases in order to find out the main causes of the rejection andthe best suitable remedy for the cause by using six sigma DMAIC methodologies.


6/34

6 | P a g e

2. DEFINE


7/34

7 | P a g e

2.1 Six Sigma Project Charter

Date: October 10, 2010

Project Name: Reducing rejection score of RFIs during Inspection & testing phase at

project site.

Process owner: QA/QC Manager

Supervisor: Mr. Iftikhar Ahmed, Black Belt / Green Belt

Project Author: M. Imran Haq Khan

Team Members:

Mr. Qazi Muhammad Furqan (QA Engineer) Muhammad Imran Haq Khan

Mr. Ramzan Nadeem (QC Engineer) Mr. Abdul Rauf (QC Engineer)

Purpose (primary reason for this project):To improve level of RFI (Request For Inspection) acceptance by reducing inspection

flaws and reduction in cost of quality.

Problem Statement

In manufacturing works our customer has serious concern about RFIs rejection percentage,

inspection and testing flaws and inspection cycle time. On weekly basis, collective rejection

percentage of RFI activities (inspection and testing) goes beyond 16% which causes delay in

delivery/completion and handover of equipment to our customer. RFI rejections affects oncost of quality of the project which shows poor manufacturing process.

Business Case:

The successful completion of this project will help the company to minimize the cost of

quality. Improvement in process will be helpful to reduce the manufacturing activity cycle

time of our product.

Goal: (expected outcome, deliverables, and or results)

The project goal is to study 100% acceptance of RFI in our manufacturing process to

determine the ability through process improvement. Furthermore to minimize the rejection

percentage up to 3%.

Scope of Project

The scope of the project is to cover the RFI cycle at both locations

Project site fabrication shop

Workshop facility (for the manufacturing of pressure equipments)


8/34

8 | P a g e

Timeline (Define, Measure, Analyze Improve and Control):

The following gate review dates are recommended for this project.

Define/Measure October 18, 2010

Analyze/Improve October 30, 2010

Control November 13, 2010

Compilation and report submission November 23, 2010

Measurable Metrics

Primary metric: RFI rejection ratesSecondary Metric: (1) Quality cost of project raised

(2) Decrease in Customer satisfaction level

Benefits

Increase in inspection effectiveness, product time, cycle time and reduce in penaltieson the project.Enhance customer satisfaction.Quality cost reduction.Overall improvement of RFI and manufacturing process.


9/34

9 | P a g e

2.2 Process Mapping:Detailed Process Flowchart

Material Receiving

Inspections

Non Destructive

Examination

In / Out put from

execution team

Acceptanc

e through

RFI

Transportation

NCR

Delay

Verify as

per Dwg.

through RFI

Yes

No

No

3rd party

reports

3rd party

reports

No

Yes

Release for

hydrostatic test

Yes

Yes

Start

End / Finish

Preparation for fit-

ups

Preparation for re-

inspection

Repair of NDE

work

Surface preparation and

painting work

Surface

preparation

& paining

verification

No

Yes

Final visual

inspection

Marking &

identification

No


10/34

10 | P a g e

Voice of Customer

Customer Satisfaction (Voice of the Customer)

The impact of cost of poor quality on the customer the customer being the externalcustomer who receives product or service that is directly impacted by the process that is thefocus of your Six Sigma project. Description, how the VOC was validated is as follows:

1. Inspection notification (RFI) 12 hour notice prior to inspection.2. Prior internal inspection with sufficient inspection data and quality record.3. Timely attending the RFI by internal QC inspector.4. Availability of resources.5. RFI rejection %age should not increase more than 3%.

Financial Benefits Assessment

The financial benefits realized as a result of your project is the time & schedule of project.The method in which these benefits were calculated, and if finance resources were used tocalculate as we as confirm the financial benefit.

Tools Application

The analytical tools (t-Test) were employed, then the results of the analysis and theconclusions we will be able to make as a result of the test.

Example:

Tool: Sample Variance F-testConclusion/Key Learning: A sample of parts was taken from the Equipment inspection Aand then repeated sampling using other equipment B, while holding all other factorsconstant. The sample size was 500 inspections an alpha of 0.05. The Fcalc based on theactual sample measurements was 553 inspections. Since the Fcalc was greater than Fcrit, Iwas able to reject the null hypothesis that there was no difference due to the type ofEquipment to be inspected. The resulting p-value confirms that the result is outside of myestablished 95% confidence for accepting the null hypothesis. This test result supportedmanagements assumption that the equipment inspections were contributing to changes inthe process variation, and allowed the project team to pursue this part of the investigationfurther.


11/34

11 | P a g e


12/34

12 | P a g e

2.4 SIPOC DIAGRAM - High LevelRFI Process Integrity Project

Supplier Input Process

Receiving Material

Marking/Layout &

Cutting

Fit-up & Welding

Activity

NED Testing

Final Inspection

Enter Time Sheets &

Job Progress

Output Customer

Pressure Testing

Release For Painting

Enter Vendor Invoices

Final QualityDocumentation

Transportation To

Process Plant

Store / Warehouse /

Vendors

Layout Supervisor /

Contractor officer

Area Supervisor /

Welding foreman

Area Engineer /

Supervisor

Area Engineer /Supervisor

Field Engineer

Area Supervisor

Painting Supervisor

Commercial / Planning

Engineer

QC Engineer /Inspector

Planning / Commercial

Engineer

Generation RFI For

Inspection

Generation RFI &

Identify Dwg.

Generation RFI & verify

Support Docs.

RFI Raised For Testing

RFI Raised For Internal& External Inspection

Supporting Documents

Presentation

Test Packages prep. &

Field Verification

RFI Raised For Painting

Inspection

Work Done As Per

SOW

Shop Dossier Prep &Verification

Preservation, Marking &

Labeling Verification

Accept / Reject Report



3rd Part Re ort

PL / Release Note

Productivity / Project

Cost Report



Contraction Cost

Report

Shop dossier /CustomerReview/Acceptance

Production Manager &

Team


Team

QC System Operation

QC Manager/QC System

Operation


Team


Team


Team


Team

Field Engineer / CustomerQA/QC Manager

Planning Engineer / Process

Plant Supervisor

QC Engineer / ProductionManager

Equipment Release

Note From Customer


13/34

13 | P a g e

3. MEASURE


14/34

14 | P a g e

3.1 SIX SIGMA LEVEL CALCULATIONS

Calculate the sigma level and DPMO of 5-nos. pressure vessels, 100 RFI raised for inspectionand testing activities fabricated in ASME workshop. The manufacturer wants to address thefunctionality and sigma level of the pressure vessel manufacturing process in 9-weeks time.

Sigma Measurements TableSigma Defects numbers per million1.5s 500,0002.0s 308,3002.5s 158,6503.0s 67,0003.5s 22,7004.0s 6,2204.5s 1,3505.0s 233

5.5s 326.0s 3.4

Project sigma is 3 because the DPMO level 74,000 which is near the 3 sigma level.

Yield Calculation of the Process 500 RFIs has 53 rejected then,Yield is Yield= (500 53)*100/500= 89.4%

Variable data output is frequency Mean of the data = 110.6Minimum and maximum of the data = 109 112

Data range= 100Variance= 1.92Standard deviation= 3.84

Z-ScoreEvaluation For Z-score measurement specification limit is USL (102) LSL (106)Z-score= (USL-mean)/standard deviationZ-score= (106-110.6)/3.84= -1.19Z-score value is -1.19


15/34

15 | P a g e

3.1.1 Process Capability

Pressure Vessel RFI Offered RFI Rejected

PV-1 112 10

PV-2 109 12PV-3 110 11

PV-4 112 10

PV-5 110 10

Interpretation of the Process Capability Diagram

Process Capability PPK = z-score/3 PPK=-1.19/3= -0.399(Process is poor capable and improvement is required)

(Note: if PPK value is grater then 1 process is capable if PPK value is less then 1 thenprocess is not capable.)


16/34

16 | P a g e

3.2 PARETO ANALYSIS DIAGRAM

Defects Counts

Mech. Damages 1Wrong Marking/Cutting 2Fit-up 5

Visual Testing (Welding) 22RT 2Pneumatic Testing 1Hydro Test 0Surface Preparation 7Painting 4Final Inspection 1Lack of supervision 8

Total 53

Basic Steps for Pareto Chart:1. Quantify the Impact of Each Defect2. Rank in DescendingOrder

NOTE:We should have at least three types of defects. If we have too many, then we may want to

group them together.


17/34

17 | P a g e


18/34

18 | P a g e


19/34

19 | P a g e

4. ANALYZE


20/34

20 | P a g e


21/34

21 | P a g e


22/34

22 | P a g e

4.3 Fish Bone Diagram

It is also called ISHI KAWA diagram or Cause and Affect diagram which shows thereal situation about the problem and helps us to find out the root cause of theproblem.


23/34

23 | P a g e


24/34

24 | P a g e

5. IMPROVE


25/34

25 | P a g e

5.1 CO-RELATION OF DIFFERENT FACTORS

IDENTIFIED IN CAUSE & EFFECT DIAGRAM

During in depth study, after cause and effect diagram definition, improvement pointshave been identified to reduce the rejection of RFI and sustain the improvement.

The following steps have been taken with the serious consideration:

1. Within the fabrication team, control frequency would be increased. If it is 1 to 2times, it should increase to 3 to 4 times to minimize RFI rejections.

2. Re-alignment of resources, from payroll list has been acquired to see the properallocation of skilled man power. During this, it was observed that fabricators,

welders and painters have been not allocated according to t heir skill andexperience. As a result, re-alignment of resource has been managed.

3. Purposely in those areas, where the inspection flaws rate was very high. Skillenhancement, training program has been delivered according to writtenprocedure.

4. Poor quality of food has been identified as a cause of rejection during fabricationprocess. Good quality of food has been provided by replacement with the pre-qualified vendor.


26/34

26 | P a g e


27/34

27 | P a g e


28/34

28 | P a g e

5.2.2. Process Capability

Pressure Vessel RFI Offered RFI Rejected

PV-1 103 3

PV-2 102 2

PV-3 102 2PV-4 101 1

PV-5 101 1

Interpretation of the Process Capability Diagram

Process Capability PPK = z-score/3 PPK=0.81(Process is still poor capable and more improvement is required, but improved

from the past)

(Note: if PPK value is grater then 1 process is capable if PPK value is less then 1then process is not capable.)


29/34

29 | P a g e


30/34

30 | P a g e


31/34

31 | P a g e

6. CONTROL


32/34

32 | P a g e

STATISTICAL PROCESS CONTROL

The points addressed in the improve phase will be monitored through the control charts inthe statistical process control. The abnormalities will be observed through the tendency ofthe data plots for special causes and corrective action will be taken accordingly.

6.1 REJECTION CHART (SIMPLE LINE GRAPH)

Date Sample Size n Rejected RFIWeek 1 23 0

Week 2 45 0

Week 3 72 1

Week 4 78 0

Week 5 97 2

Week 6 90 0

Week 7 60 3

Week 8 30 2

Week 9 14 1

Comments:

To Conclude, Control Plan would be considered and then the rejections are improved and sustain theimprovement like;

1. Re-Alignment of resource - Taking relevant people in relevant place

2. Provided good food by changing pre-qualified sub-contractor

3. In-situ relevant training has been arranged to all group of vessel fabrication yard

4. Flawless Startup Initiative (FSI) system has been launched for in depth identification

of checkpoints for smooth & in time completion of product with maximum customer satisfaction


33/34

33 | P a g e


34/34

Summary

Our fabrication shop situated near project site has not achieved Six Sigma qualitylevels for all five pressure vessels as requested by their customers. Basically it isrequired to apply Six Sigma problem solving methodology to establish an

improvement strategy that minimizes rework costs, yet achieves the desired qualityobjective.

Problem statement

To bring the key process output variables within Six Sigma quality level of < 3.4DPM. Cp 2.0 and Cpk 1.67

Analysis & Control

RFI control frequency should be increased. If it is 1 to 2 times, internal checksshould increase upto 3 to 4 times to minimize RFI rejections.

Re-alignment of resources, to see the proper allocation of skilled man power. Purposely in those areas, where the flaw rate was very high. Skill enhancement, training

program should be delivered. Food quality should be checked frequently and ensure good quality of food for the staff.

Recommended Control

Implement Flawless Startup Initiative (FSI) system for in depth identification ofcheckpoints for smooth & in time completion of product with maximum customersatisfaction.

Establish control plan for ongoing monitoring of every 10 RFI raised.

****************