six sigma project on controlling rubbing issues in lsa 442-160 kva 410 hp machine
DESCRIPTION
This Six Sigma Project submitted by Advance Innovation Group student intended for Controlling Rubbing Issues in LSA 442-160 KVA 410 HP Machine. The objective to increase overall productivity and minimize the waste (rework) and scrape to increase sales orders. Continuous rubbing issue leads high scrap and rework cost which is very high. 64 random machines picked up out of 420. Current process capability is 1.5. Additionally, it is advisable that you also visit and subscribe Advance Innovation Group Blog (http://advanceinnovationgroup.com/blog) for more Lean Six Sigma Projects, Case Studies on Lean Six Sigma, Lean Six Sigma Videos, Lean Six Sigma Discussions, Lean Six Sigma Jobs etc.TRANSCRIPT
Advance Innovation Group
Control Rubbing issue in LSA 442-160 KVA 410 hp machines
Voice of the Customer-VOC
2
Customer CommentsCritical to Quality-
CTQ’s
Managing DirectorCost of rework and scrap is very high during the First
Quarter of FY12.
Rubbing in LSA 442 160 kva 410 hp machine.
VP – Marketting
Handover of LSA 442 160 kva 410 hp machines is not done as per commitments during the first quarter of FY-12. We are losing sales order due to this as this frame is the most
priority one .
Head- Manufacturing
During The first Quarter of FY-12 we have continuous rubbing issue of LSA 442 160 KVA 410 hp machines
reported from Test bed . Only 120 machines out of 420 passed as first time right else all the machines are first
reworked and then passed. Due to which the rework and scrap cost is very high and the machines are not handover
as per commitments to marketing which leads to lost of sales.
Project Charter
Business caseABC Corp. is one of the good brands in the field of Alternator manufacturing industries which has its name in the market for providing 100 % quality product on time to their customer . During the first Quarter of FY -12 .We observed that we have a sales plan of 420 LSA 442 160 KVA 410 hp machines but due to continuous rubbing issue in the same production was not able to handover machines timely resulting in lost of sales and high rework cost. This problem is to be removed asap as this may also impact our long tern business planning and new business generation from the existing customers.
Team
Problem Statement: Continuous Rubbing Issue reported from test bed for LSA 442,160 KVA 410 hp machines. This leads to High Scrap and Rework cost equal to 1875210 INR.
Goal Statement: Zero complaints of Rubbing to be reported from test bed and customer till May’12.
In Scope : Rubbing issue in only LSA 442-410 hp machine.
Out Scope : Rubbing issue in any other frame sizes.
Milestones Target Date Actual date
D 9th Jan 2012 9th Feb M 10th Feb 10th MarA 11th Mar 20 th AprilI 21st April 30th AprilC 25th April 10th May 2012
BU Head Neha SharmaOperating Manager Shishir Singh
Qperating Manager Quality Mithlesh Nautiyal
Process Owner Naveen JoshiProject Leader Pradeep
Team Member Ravi, Sunil, Smita, Ram
ARMI
Key Stakeholders
ARMI Worksheet
Define Measure Analyze Improve Control
Vijay Bhutani I I I I I
Baljeet Yadav I &R I &R I &R I &R I &R
Tata Udayakiran I &R I &R I &R I &R I &R
Manor Joshi A & I A & I A & I A & I A & I
Ankit Chandra I ,A &M I ,A &M I ,A &M I ,A &M I ,A &M
Saroj,Brind &Harshita
I & M I & M I & M I & M I & M
Vijay Bhutani I I I I I
Baljeet Yadav I &R I &R I &R I &R I &R
A – Approval of team decisions I.e., sponsor, business leader, MBB.R – Resource to the team, one whose expertise, skills, may be needed on an ad-hoc basis.M – Member of team – whose expertise will be needed on a regular basis.I – Interested party, one who will need to be kept informed on direction, findings.
Communication PlanInformation Or Activity Target Audience Information Channel Who When
Project Status Manor Joshi E-mails Pradeep Weekly
Tollgate Review Vijay Bhutani , Baljeet Yadav & Tata Udayakiran
E-mails or Meetings Pradeep As per Project Plan
Project Deliverables or Activities Saroj , Brand , Harshita & Aditaya
Emails, Meetings Pradeep Weekly
RASIC
RASIC Chart
Responsible
Solely and directly responsible for the activity (Owner) - Includes approving authority (A)
Roles Vijay
BhutaniBaljeet Yadav
Tata Udayakir
an
Manor Joshi
Ankit Chandra
Saroj Shankar
Brand Prate
Harshita Mallik
Approve
Reviews and assures that the activity is being done as per expectations
Support
Provides the necessary help and support to the owner
Inform
Is to be kept informed of the status/progress being made
Consult
Is to be consulted for this activity for inputs
Activities
Define
A C C S R S S S
Measure
A C C S R S S S
Analyse
A C C S R S S S
Improve
A C C S R S S S
Control
A C C S R S S S
CTQ Tree
St. Stacking Improper if air gap flat strip of 1mm inserted after keeping T
in it.
St. Stacking Improper if air gap flat strip of 1mm inserted after keeping T
in it.
Ex Rt and St bend if the gauge don’t rotate after inserting.
Ex Rt and St bend if the gauge don’t rotate after inserting.
B/Hsg Run out will be OK if within 0.05. both DE
NDE side
B/Hsg Run out will be OK if within 0.05. both DE
NDE side
Rubbing Issue in LSA 442 – 410 hp machine
Rubbing Issue in LSA 442 – 410 hp machine
CTQs
Mandrel used for Main Rt stacking is
defective if below mentioned specs not present length 415± 5 mm , OD 140± 1 mm
and visually OK .
Mandrel used for Main Rt stacking is
defective if below mentioned specs not present length 415± 5 mm , OD 140± 1 mm
and visually OK .
Initial Unbalance in Rotor is high if DE side not within 170-180 and on NDE side 340-395
Initial Unbalance in Rotor is high if DE side not within 170-180 and on NDE side 340-395
Bendness in Shaft checked visually.
Bendness in Shaft checked visually.
Rt. Run out will be OK if +veand within 0.05 on all pole both DE & NDE side
Rt. Run out will be OK if +veand within 0.05 on all pole both DE & NDE side
Assembly fixture OD 830 ±0.5 and 6 * Ø25 ±0.5
Assembly fixture OD 830 ±0.5 and 6 * Ø25 ±0.5
Concentricity out in DE/NDE spigot if ID 450 mm
Concentricity out in DE/NDE spigot if ID 450 mm
Fan hub will be Concentric if its ID is 139
±0.5
Fan hub will be Concentric if its ID is 139
±0.5
Machine mounted over test bed have to be tightened with 6 bolts else defect
Machine mounted over test bed have to be tightened with 6 bolts else defect
Mandrel used for Main St stacking is
defective if below mentioned specs not
present length 540±2mm , OD 230± 1 mm and inclination OK
.
Mandrel used for Main St stacking is
defective if below mentioned specs not
present length 540±2mm , OD 230± 1 mm and inclination OK
.
SIPOC
S I P O C
Planning
Receive Material From
Vendor
QC Check
Store
Machining and
Stacking operation
Production Plan
Arrival of material
Received QC
passed material
Material for
production
Machined rt. & st.
Wound st. & rt.
Assembled m/c
Tested m/c
FG
Dispatched
Production.
Finance & QC
QC,Store
Store, Production
Wdg shop
Assembly shop
Testing deptt.
Production
FG Store
LS
Orders.
Material Order
Critical Checks
QC Passed Material
Plan,BOM
Machined mat., jb card
Wound Mat Job Card
Assembled m/c
Tested m/c
Jc and test certificate
Order detail, fg stock
Store
Marketing
QC
QC
Store
M/c Shop
Wdg shop
Assembly Shop
Production
Market
Wdg Operation
Assembly Operation
Dispatch
Paint
Routine Testing
Data Collection Plan mMEASURE
KPI Operational Definition Defect Def Performance StdSpecification Limit
OpportunityLSL USL
Average failure rate of LSA 442 160 kva 410 hp machine at final testing
Assembled Machine of LSA 442 160 kva 410 hp pass the testing stage and move
for painting in one time without any rework on machine.
Rework on machine after
testing
100 % machine pass test bed without
rework0
Maximum no of machines
testedDaily
KPI Data Type Data Items Needed
Formula to be used Unit
Plan to collect Data Plan to sample
What Database or Container will
be used to record this data?
Is this an existing
database or new?
If new, When will the
database be ready for use?
When is the planned start date for data collection?
Average failure rate of LSA 442 160 kva 410 hp machine at final
testing
Discrete
Total no of machines
tested and Reworked machine.
Reworked machine/ Total No
of machines tested
Pass % machines Excel Existing NA Already
started
Monitor the tested
machine data of LSA 442
machines on daily basis
Validation Measurement System -Effectiveness & Efficiency
mMEASURE
For the purpose of data validation, 64 machines have been re-tested for the time taken.
Procedure Used:• 64 random machines picked up from 420 machines. The samples have been
randomly generated by Axus Pro and we asked two Testing Engineer to re-test the 64 Machines.
• On verification, we found that 4 machines were differently resulted in the 64 machines which were re-tested.
Effectiveness % = Number of samples where both measurement were similar * 100 Total Number of samples under consideration
= 60 * 100 = 93.75% 64
Effectiveness at 93.75% with 64 Machines is good enough, and we conclude that the measurement System is adequate.
Current Capability - Process Sigma Level mMEASURE
DENOMINATOR VALUES
DPO 0.71
DPMO 714285.71
FIRST TIME RIGHT(FTR) 95.00%
FAIL % 71.43
Z LONG TERM 0.00
Z Short TERM 1.50
Z Score of the process is really poor, there is immediate need to improve the process capability
Organize Potential Cause – CE or Fish Bone Diagram
Factors identified through brainstorming
aAnalyze
Organize Potential Causesa
Analyse
High Medium Low
In Control
Rotor Initial Unbalance, Rotor Run Out,
Stator Stacking, Calibration of assembly
Fixture and gauges.
Main Stator Stacking Mandrel,
Bendness in Shaft,Training to operators
Related to use of gauge.
Main Rotor Stacking MandrelEx. St & Ex. Rt. Bend
Out of Control
Concentricity of Body Housing
Concentricity of DE , NDE and Fan Hub B/ Hsg Run out
Impact
Con
trol
Pareto of Potential X’s
13
Data to be collected around the Potential X’s – Impact of X’s on Project Y to be statistically validated using Hypothesis Testing
aAnalyze
Proposed tests according to problem and factor’s data type
S No. Potential Cause Operational Definition Data Type Test of be performed
1 Initial Unbalance Initial unbalance is ok if unbalance at DE side <170 and at NDE side < 355. Discrete Cross Tabulation Test
2 Rotor Run Out Rotor run out is ok if within 0.05 at all poles on DE , Centre and NDE side Discrete Cross Tabulation Test
3 Bendness in shaft Visually if shaft is not ok Discrete Cross Tabulation Test
4 Stator Stacking Stator stacking is proper if air gap inserted <=1mm. Discrete Cross Tabulation Test
8 Exciters Exciter is Ok if gauge easily inserted and rotate freely Discrete Cross Tabulation Test
15
Cross Tabulation Test Result for Initial Unbalance
aAnalyze
Tabulated statistics: Status, Initial Unbalance
Rows: Status Columns: Initial Unbalance
In Out limit limit All
FAIL 198 102 300PASS 120 0 120All 318 102 420
Cell Contents: Count
Pearson Chi-Square = 53.887, DF = 1, P-Value = 0.000Likelihood Ratio Chi-Square = 81.034, DF = 1, P-Value = 0.000
P value of Initial Unbalance is <0.05 therefore Impact of Initial Unbalance(X) on fail of machine(Y)
Rotor Initial Unbalance Data of Fail Machine
16
Total No Of Machines failed
due to high Initial Unbalance in
Rotor
Expected Acceptable Observed Average
Initial Unbalance Initial Unbalance
DE NDE DE NDE
102 170 355 178 380
REMARKS:-
• High Initial Unbalance is our Vital X.• 102 machines failed out of 420.• Observed average Initial Unbalance is very high as compared to acceptable.
Conclusion :-
• Rotor Preparation Process to be Modified.
17
Cross Tabulation Test Result for Rotor Run Out
aAnalyze
P value of Rotor Run Out is <0.05 therefore Impact of Rotor Run Out(X) on fail of machine(Y)
Tabulated statistics: Status, Rotor Run Out
Rows: Status Columns: Rotor Run Out
In In Out limit Limit limit All
FAIL 204 0 96 300PASS 0 120 0 120All 204 120 96 420
Cell Contents: Count
Pearson Chi-Square = 420.000, DF = 2, P-Value = 0.000Likelihood Ratio Chi-Square = 502.546, DF = 2, P-Value = 0.000
Rotor Run Out Data of Fail Machine
18
Total No Of Machines failed due to high Rotor Run Out Expected Acceptable Observed Average
96
Rotor Pole DE Center NDE Rotor Pole DE Center NDE
1st Pole <=0.05 <=0.05 <=0.05 1st Pole 0.07 0.09 0.07
2nd Pole <=0.05 <=0.05 <=0.05 2nd Pole 0.09 0.06 0.07
3rd Pole <=0.05 <=0.05 <=0.05 3rd Pole 0.07 0.08 0.1
4th Pole <=0.05 <=0.05 <=0.05 4th Pole 0.079 0.1 0.07
REMARKS:-
• High Rotor Run Out is our Vital X.• 96 machines failed out of 420.• Observed average Initial Unbalance is very high as compared to acceptable.
Conclusion :-
• Rotor Preparation Process to be Modified.
19
Cross Tabulation Test Result for Bendness in Shaft
aAnalyze
P value of Bendness in Shaft is <0.05 therefore Impact of Shaft bend (X) on fail of machine(Y)
Tabulated statistics: Status, Bendness in Shaft
Rows: Status Columns: Bendness in Shaft
In In Out limit Limit limit All
FAIL 245 0 55 300PASS 0 120 0 120All 245 120 55 420
Cell Contents: Count
Pearson Chi-Square = 420.000, DF = 2, P-Value = 0.000Likelihood Ratio Chi-Square = 502.546, DF = 2, P-Value = 0.000
Shaft Bend Data of Fail Machine
20
Total No Of Machines failed
due to Shaft BendExpected Acceptable Observed Average
96 Straight Bend
REMARKS:-
• Bend Shaft is our Vital X.• 96 machines failed out of 420.• Found visually that some of the shafts are also bend.
Conclusion :-
• Rotor Preparation Process to be Modified.
21
Cross Tabulation Test Result for Stator Stacking
aAnalyze
P value of Stator Stacking is <0.05 therefore Impact of Stator Stacking(X) on fail of machine(Y)
Tabulated statistics: Status, Stator Stacking
Rows: Status Columns: Stator Stacking
In In Out limit Limit limit All
FAIL 176 0 124 300PASS 0 120 0 120All 176 120 124 420
Cell Contents: Count
Pearson Chi-Square = 420.000, DF = 2, P-Value = 0.000Likelihood Ratio Chi-Square = 502.546, DF = 2, P-Value = 0.000
Stator Stacking Data of Fail Machine
22
Total No Of Machines failed due to stacking
Expected Acceptable Observed Average
Air gap Air Gap
124DE NDE DE NDE
0<=1 0<=1 2.1 2.4REMARKS:-
• Improper Stacking is our Vital X.• 124 machines failed out of 420.• Observed average air gap is very high as compared to acceptable.
Conclusion :-
• Stator stacking Process to be Modified at Precision.
23
Cross Tabulation Test Result forExciters
aAnalyze
P value of Exciters is <0.05 therefore Impact of Exciters (X) on fail of machine(Y)
Tabulated statistics: Status, Ex. St. & Ex. Rt.
Rows: Status Columns: Ex. St. & Ex. Rt.
In In Out limit Limit limit All
FAIL 255 0 45 300PASS 0 120 0 120All 255 120 45 420
Cell Contents: Count
Pearson Chi-Square = 420.000, DF = 2, P-Value = 0.000Likelihood Ratio Chi-Square = 502.546, DF = 2, P-Value = 0.000
Exciter Stator and Rotor Data of Fail Machine
24
Total No Of Machines failed due bendness in
Exciters
Expected Acceptable Observed Average
Exciter Stator and Rotor Exciter Stator and Rotor
45Gauge insert easily and
Rotate Gauge not insertREMARKS:-
• Exciter Bendness is our Vital X.• 45 machines failed out of 420.• Gauge not inserted in Exciters.
Conclusion :-
• Exciter’s Quality check Introduced before and after winding
aAnalyze
Vital X’s That are Impacting the Machine Failure due to Rubbing
S No. Potential Cause Operational Definition Data Type Test of be performed
1 Initial Unbalance Initial unbalance is ok if unbalance at DE side <170 and at NDE side < 355. Discrete P Value - 0.00
2 Rotor Run Out Rotor run out is ok if within 0.05 at all poles on DE , Centre and NDE side Discrete P Value - 0.00
3 Bendness in shaft Visually if shaft is not ok Discrete P Value - 0.00
4 Stator Stacking Stator stacking is proper if air gap inserted <=1mm. Discrete P Value - 0.00
8 Exciters Exciter is Ok if gauge easily inserted and rotate freely Discrete P Value - 0.00
QFD
Quality Function Deployment (QFD) D M A I C
Implementation Road MapD M A I C
Faliure Mode Effect Analysis (FMEA)
FMEA
D M A I C
Before and After & Project Process
Control Analysis D M A I C
The Control Chart show that Defect is zero after improvement.
Before Project After Project
The Control Chart show that Defectives is zero after improvement
Pre and Post Project Process Control Analysis D M A I C
Before Project After Project
This Graph Shows that after completing the project the Rubbing issue reported from test bed is reduced to Zero.
Sales Plan Vs Rubbing Issue in LSA 442 160 KVA 410 hp Machines D M A I C
Oct'11
Nov'11
Dec'11
Jan'12
Feb'12
Mar'12
Apr'12
May'12
Jun'12
July'12
Aug'12
Sept'12
Oct'12
Nov'12
Dec'12
Sales pLan
NaN
165 145 110 0 0 0 0 67 65 110 60 70 51 81 117
Rubbing Issue
NaN
125 100 75 0 0 0 0 0 0 0 0 0 0 0 0
10
50
90
130
170
No
. O
f M
ac
hin
es
Thank You