Post Graduate Professional Development Program in
Energy Management and Climate Action
(Nov 2020 – July 2021)
Project Report
Name Harsh Vardhan
Email harshsu_express1@rediffmail.com
Date 18.11.2021
Contact No. 9667214130

Zero Rejection due to TWB Crack TWB
PROJECT : RESOURCE CONSERVATION
Elimination of TWB Crack in Door Panels
THEME
VASTUPAL
Team Members
SAURABH
DATA COLLECTION & TARGET
No
of
Rejected
Parts
ROADMAP
❖ Methodology
Fixation
❖ Grasping the
Facts
❖ Process
Stabilization
❖ Visual
standardization
5th Step
Sustain
1st Step
2nd Step
4th Step
System
Build up
Analysis
Initiation
3rd Step
Implem.
Theme
Selection
& Target
Setting
Situation
Analysis
& RCA
Establishing
Standards
C/M
implement
ation
Sustain
the
Process
❖ Target Setting
❖ C/M Trial &
Imp.
❖ Result
Check
1
Actual Target
0.0
TWB Crack
(Jan’21 – Jun’21)
0.1%
102
19
51
14 11 6 2 0
Weight of 1 Part : 6.5 kg
Weight of 102 Parts : 663 Kg
Eliminate the Wastage of Steel
to 0 by Controlling Rejection
HARSH VARDHAN
(Team Leader)

UNDERSTANDING OF STEEL BLANK:
WHAT IS STEEL BLANK…??? Unfinished Piece of Steel that has been Stamped out from a Steel Coil which is of
different Sizes as per Part Specification ( thickness 0.5 mm to 2 mm)
HOW IT IS PROCESSED…???
Steel Coils Processing on Blanking Line with Dies Steel Blanks
WHAT IS TWB…???
TAILOR WELDED BLANKS (TWB) are made from individual sheets of steel of same or different
Grade, Thickness, Strength and Coating which are joined together by LASER WELDING.
3D View 3D
LASER WELDING
0.65mm
1.2mm
Side View 側面図
LASER WELDED OR TWB BLANK
2
TWB Welding
TWB
TWB Blanks made of two sheets of different thickness & steel blanks production know-how done.

3
UNDERSTANDING OF TWB PART PRODUCTION:
Bolster
Upper
Die
Lower
Die
Lower
Die
Pressure
Pad
Bolster
Part
Scrap
Chute
Part
Part Production Process Flow at Press…
TWB Part
1.2
mm
0.65
mm
TWB Blanks Draw Trim Bend
Process Understanding of TWB Part Production done by using TWB Blanks.
Draw Trim Bend
Input Output
Process

4
REDUCTION OF THE WEIGHT
✓ Optimization of material use – reduction of material use
and less scrap
✓ Right steel grade and material thickness where needed –
tailor made solution for the part design and weight
savings
WHY TWB…??? The Right Steel Grade is in the Right Place, in the Right Thickness for
each part to reduce weight and to improve strength & safety of the vehicle.
ADVANTAGES OF TAILORED BLANKS
TWB PARTS APPLICATION & ADVANTAGE
INCREASED TECHNICAL PERFORMANCES
✓ Higher stiffness
✓ Better energy absorption
✓ Better crash behavior
SIMPLIFICATION OF THE PROD. PROCESS
✓ Reduction of the number of parts
✓ Reduction in the stamping and assembly tools
✓ Shorter manufacturing process
Data Analysis & Process Flow study done.
SUPPLYING
BLANKS
BLANKS
RECIEVING &
STORING AT
PLANT-TKR
PRODUCING
PARTS AS PER
PRODUCTION
PLAN
PARTS
QUALITY
CHECK
PARTS
STORAGE
CHECKING OF
PARTS AT Q –
GATE
PACKING OF
PARTS FOR
DELIVERY
PARTS
DELIVERY AT
PLANT
PROCESS WORK FLOW : PRESS

➢ High Rejection Rate
➢ Poor Quality of Parts
➢ Line Loss
➢ Rechecking of Parts increasing
➢ Repair Man-hour loss
➢ Leakage Problem in Car
➢ Major cost in Door Replacement
➢ Impact on CBU Quality &
Customer Satisfaction CBU
Part setting/Cutter
clearance
Trim condition found OK
Blank setting Found ok
Blank touching on gauges/ No
blank shifting
DOOR PNL TWB
AREA CRACK
No burr/ Trim condition
Draw Die
(OP-10)
Bending block
profile/movement
Part found ok
No deform/No cam jam
Trim Die
(OP-20)
Bend Die
(OP-30)
FACTOR CONTROL ITEM ACTUAL STATUS
CONTROL STD
PROBLEM
TWB condition TWB Defects may occur
No TWB Defects allowed
Raw
Material
TREE STRUCTURE ANALYSIS FOR CRACK GENERATIONｰ
During detailed study, suspected Issue found in Raw Material Quality as No method to check TWB Blanks at HCIL so need
to take action at Supplier End.
Cushion Pressure Found ok
Should be as Specific Part Std
Die height of every
Part
Found ok
Should be as per Specific Part
Std.
Draw Die Bead Found Ok
No scratches/No Chrome Peel
off in Bead Area
TWB CRACK ANALYSIS & ITS IMPACT : TWB 6
Edge Crack
Speaker Fitment Issue
Moulding Fitment Issue
IMPACT OF TWB CRACK
Input
R/M
Process
Output
Part
❑ Draw
❑ Trim
❑ Bend
❑ Part
Found
Crack
near TWB
❑ R/M
material
condition
ok
Concern

7
BLANKING LINE
PROCESS FLOW AT SUPPLIER
SUPPLIER PROCESS & PARAMETER STUDY
TWB M/C OUTPUT
ERICHSON TEST FAILURE
ERICHSON TESTING M/C CARCK OBSERVED NEAR TWB
TWB DEFECTS IN BLANKS TENSILE TEST
FAILURE
INADEQUATE
WELD BEAD
TWB WELDING
Supplier Process & Parameter Output Study Done.
➢ Mis-match
➢ Upr Weld Bead
➢ Lwr Weld Bead
➢ Porosity
➢ Undercut
➢ Cracks
➢ Lake of fusion
➢ Lake of penetration
➢ Slag inclusion

SITUATION ANALYSIS FOR DEFECT GENERATION
DEFECTS IN TWB WELDING
LASER AT NEW
POSITION
430
310 290
130
98 92 90 80 70
0
100
200
300
400
500
Laser Beam Co-
ordinate
Found not ok
Lens Condition Dirt Found
No Dirt allowed on Lens
Should be at matching Point
of Both Sheet( X:0, Y:0)
Input
Material
Focal Length of Lens Found ok
Should be as per Std. 3mm
Burr & Trim Line
Condition
Burr & Trim Line not
found ok
Burr: 10% of sheet thickness
Trim Line: No damage
allowed
Atmospheric
Parameter
Found not ok as per
Std.
Laser Speed Found as per std.
6.0 - 6.5 m/min
Temp: 20C – 30C
Humidity: 40-70%
Laser Power O/P Found not ok
O/P should be as per Std
( 2 – 3kW)
TWB
Process
8
Fumes collecting on Lens affects
power O/P & defects starts to occur
FACTOR CONTROL ITEM ACTUAL STATUS
CONTROL STD
TREE STRUCTURE ANALYSIS FOR TWB DEFCETS
Types of Defects
No
of
Parts
Undercut Bead Width Mismatch
TWB REJECTION ANALYSIS AT RPSC
TWB PROCESS UNDERSTANDING FOR DEFECT GERNERATION
TWB WELDING
Ok TWB
Welding
Manual Cleaning of Lens leads LASER to Deflect in Y Direction leads to
defect generation
TWB WELDING
LASER AT OLD
POSITION
Welding with
Defects
LASER
CO-ORDINATES
Laser Deflects in Y Direction due to manual cleaning
Concern ok

WELDING
DIRECTION
GANTRY
Y-AXIS
X-AXIS
Y-AXIS
THIN
SHEET
THIN
SHEET
THICK
SHEET
THICK
SHEET
OFFSET
(+VE)
(-VE)
(+VE)
(+VE)
(-VE)
(-VE)
Y Co-ordinate fixed after trial
Setting of Y –Axis & Defects Range Stand.
COUNTERMEASURE-1 9
Y Axis offset value & Range for Defects fixed to eliminate TWB Defects
500 Sample checked to freeze Parameter after lens cleaning
TWB Welding Process Top 3 Defects Range Observed Laser Parameter Observed
1. Y –Axis Offset : 0.19 – 0.28 mm
2. Laser Power O/P: 2.5 – 2.9 kW
3. Laser Speed: 6 – 6.5m/min
Range Standard set for all three major defects
1. Mismatch: 0.3 – 0.6 mm
2. Bead Width : 0.4 – 1.2 mm
3. Under Cut: 0 – 0.05 mm
PARAMETER FIXED AFTER TRIAL &
VALIDATION
Process Name LASER WELDING Part Number
Machine Number TWB Part Name
MaterialDescription :-
Description Part Dimensions Material Traciability at
Machine
St. Edge(H. Th.) 0.08/0.05
BLANK 1 1.15X1100X330 Burr Lev.(H. Th.) 0.03
BLANK 2 0.63X1310X1030 St. Edge(L. Th) 0.05
BLANK 3 Burr Lev.(L. Th.) 0.03
Process Parameter:-
Parameter level Sample Size
Parameter Sample-1 Sample-2 Sample-3 Sample-4
Station No.-1
Offset(Y) 0.10 0.13 0.16 0.19
Power(kW)
2.5 176 91 96 101
2.6 177 92 97 102
2.7 178 93 98 103
2.8 179 94 99 104
2.9 180 95 100 105
Station No.-2
Offset(Y) 0.10 0.13 0.16 0.19
Power(kW)
2.5 171 136 141 146
2.6 172 137 142 147
2.7 173 138 143 148
2.8 174 139 144 149
2.9 175 140 145 150
0.22 0.25 0.28 0.31
106 111 116 121
107 112 117 122
108 113 118 123
109 114 119 124
110 115 120 125
151 156 161 166
152 157 162 167
153 158 163 168
154 159 164 169
155 160 165 170
Test Name Power Sample-1 Sample-2 Sample-3 Sample-4
Erichsion test
Station
No.-1
2.5 O O O O
2.6 X O O O
2.7 X O O O
2.8 X O O O
2.9 X O O O
Station
No.-2
2.5 O O O O
2.6 O O O O
2.7 O O O O
2.8 O O O O
2.9 X O O O
Tensile Test
Station
No.-1
2.5 O O O O
2.6 O O O O
2.7 O O O O
2.8 O O O O
2.9 O O O O
2.5 O O O O
2.6 O O O O
2.7 O O O O
2.8 O O O O
2.9 O O O O
Bead Value(UPPER)
Station
No.-1
2.5 O O O O
2.6 O O O O
2.7 O O O O
2.8 O O O O
2.9 O O O O
Bead
Value(LOWER)
Station
No.-1
2.5 O O O O
2.6 X O O O
2.7 X O O O
2.8 X O O O
2.9 X O O O
X X X X
O X X X
O X X X
O O X X
O O O X
X O O O
O O O O
X O O O
O O O O
O O O O
O O O X
O O O X
O O X X
O X X X
X X X X

10
COUNTERMEASURE-2
Control of Temp & Humidity to eliminate TWB Defects
If temp is more than std then working
of Laser Welding components will not
be proper and abnormalities found
during welding.
No method to monitor Temp & Humidity while welding Poka-Yoke done by deploying Alarm to monitor for any
change
Eliminate TWB Defects in case of Sheet Damage
Laser welding done if any Sheet Damage/Edge Blunt/Gap is there
between both sheets leads to poor Welding
Impacts Working
Components
PLC Program
changed that if
camera detects
such problem
then
automatically
Laser welding
will stop &
reject the blanks
Poka-Yoke done to stop welding & reject blanks in case of Sheet Damage & Temp, Humidity Problem
Std: Temp: 19C – 21C, Humidity: 50 – 70%
Humidity
Temp.
Poor
Welding
If temp & humidity goes more than std then it gives signal
& alarms the operator & action taken accordingly while
TWB Welding
Sheet Damage
Welding with
defects due to sheet
damage
Poka-Yoke done by stopping welding as soon as camera
Detects The sheet damage
Sheet Damage Sheet Damage

11
METHODOLOGY BEFORE & AFTER COUNTERMEASURE
Methodology to check TWB Blanks Before Countermeasure
Methodology to check TWB Blanks After Countermeasure
Blank Loading
on TWB
machine
Process the
TWB Blanks in
Machine
Monitor the
Parameter(
Laser Speed,
Power O/P) in
check sheet
Check TWB
Quality
Manually 100
% Visual &
Record the
parameter in
check sheet
Blank
Loading on
TWB
machine
Check
Parameter
for both
stations
Do lens cleaning
& set Y offset
value as defined
after 1500 to
2000 Parts
Monitor
temp,
Humidity &
take action
accordingly
Fill the
change
mgmt. sheet
in case of any
change point
Monitor the
Parameter(
Laser Speed,
Power O/P)
in check
sheet
Machine will
automatically
Reject the
TWB
Defected
Blanks
Visually, chances of inspection miss
1 2
2
Auto Rejection of Defected TWB Blanks
Methodology changed after taking C/M to eliminate TWB Defect generation
1
Change Mgmt Sheet
Parameter Recording

RESULTS & STANDARDIZATION.
➢ Zero Rejection
➢ Zero Handwork
➢ Team work improved
➢ Confidence level
improved
➢ Problem solving skills
improved
➢ Part Quality Improved
➢ Felt joy of working
➢ Piling OPS Updated
➢ OPL made for better
understanding at Q-
Gate & Online
➢ Quality OPS updated
➢ Process Validation
done
➢ Process Parameter
recorded in Lot check
sheet
➢ Training given to all
concerned on line
Month-wise number of TWB parts of all models
102
Before After
Zero
No of Parts Crack
No
of
Parts
Total Parts
Produced Crack
203203
Zero
RESULTS
INTANGIBLE BENEFITS STANDARDIZATION
TWB Inspection Report
QA Lot Check Sheet
12
Before
0.65 Tonnes Scarp in 6
months --> 1.3 Tonnes
scrap annually.
After
1.3 Tonnes Metal
Saving Annually
Annual Electricity Saving :
Power Consumed to Produce 1.3
Tonnes of Steel = 9.8 Mwh (7.5
Mwh/ tonne * Source Data :
Ministry of Power)
9.8 Mwh Annually --> 9800 units
of Power of Nation Conserved.
Monetary Benefits :
1 Piece Cost - Rs. 1150/-
Net Saving = 1150 x 102 = Rs. 117300/-
Emissions per unit Electricity Generation = 0.9 kg Avg. (Source : Ministry of Power)
9800 Units ≈ 8820 Kg of Emissions --> 8.8 Tonnes of Emissions Reduced

THANK YOU