Deployed Lean Manufacturing in fabrication of Exhaust After Treatment System Rack made for VOLVO / Mack Trucks used Lean to increase productivity by 50% and Six Sigma
methodology to resolve complex design issues, improve quality controls for sustained improvement
6. VOLVO Patented Design
EATS-Exhaust After Treatment System
EATS uses Selective Catalytic Reduction SCR and a Diesel Particulate
Filter DPF to filter & convert (treat) Nox into CO2, which exits
through the exhaust stack
EATS Rack , made by Mancor Automotive, is the integrated final
product assembly of SCR and DPF
• EATS standard cost = $570/pc, (material=$180, Labour= $380)
• 2013 Annual volume = 2000 units (8/day, 40/week)
• 2014 demand increased from 2000 to 3000 units, (8 to 12
units/day)
• Mancor batch & queue production unable to keep up with
increased Volvo demand due to multiple issues
7. 110 +/-5 mm
• Over 300 components
all made in house
• All Welded together
• Squareness must be
within 5mm top to
bottom
• Volvo customer
• Mounted around truck
cabin
9. Manufacturing and Assembly Concerns
1. Pipe vs Frame Brkt width
width +/- 5mm
2. Pipe to Frame Bracket- Joint
Integrity
3. Fully Groomed w/ DPF/SCR
4, Supplier/MMD/or Both
5. Positioning stops on DPF/SCR
+/-5 mm
10. 1. Volvo plant shut down for 2 days due to EATS
shortage costing $50K/day penalty
2. Production unable to meet Volvo increased
demand of 50% from 40 to 60pcs/week,
3. Unresolved product/design issues causing
30% Internal Quality reject rate , and limiting
max throughput 8 units/day on 2 shifts
4. Volvo lead time = 3 days, Mancor actual cycle
time= 4.5dasy for 1 EATS rack,
11. 1. Redesign parts to eliminate profile
gaps and standardize
2. Product quality by 80%, reduce reject rate
from 42% to <5%
3. Product Lead time by 50% (from 4 to 2
days)
4. Productivity by 50%, from 8-12pcs/day
Estimated Savings= $600K to $800K
12. 1. Internal Final Inspection Quality Reject Rate
=31% being reworked in-line
2. NO PFD, VSM , NO FMEA,
3. Production running Batch & Queue with
high WIP
4. Max Production Capacity 8pc/day using 2 shifts
(6 people)
5. Batch Production with high WIP > 33
13. 1. VOLVO FINAL ASSY DESIGN,
2. Internal drawings incorrect
3. 3D Model incorrectly exported into 2D CAD
drawings, incorrect nominal dimensions and
tolerances
4. No revision history, drawings not updated.
Component parts being modified daily
grinding or welding
5. Product design Issues causing excessive
Non-Value Add (NVA) welding to fit parts
14. 1. TACKING = 90min (50min modifying
components fitting + 40min welding filling gaps
between parts)
2. ROBOT WELDING= 90min (20min robot + 45 min
touch up)
3. SHOT BLASTING= 15MIN/PC
4. FINAL INSPECTION 33% REJECT RATE
5. JOINING = 75MIN -(joining + reworking
defects)
6. PAINTING= 45MIN
TOTAL ACTUALL TIME =315MIN = 5.2HRS/PC
STANDARD TIME= 3HRS/PC
16. All 3 parts need to be aligned and welded
Currently being done without any support fixture.
1
32
19. 0.5 to 1” gaps had to be welded
before fitting
24. 1. Redesigned 5 main SCR and DPF parts which
reduced profile gaps from 15mm to < 1mm
a) Reduced Non-Value Add welding by 54”
b) Reduced overall fit & tack cycle time by 70 min
2. Validated new design in production on 240
pcs, 4 different runs with no issues.
3. Created an ECN, with As-Built/Red line
drawings with revised part profile dimensions
and obtained Volvo Engineering approval
4. Trained in-house design engineers on Design
Validation and Product Reliability testing,
DFMEA and PFMEA
5. Developed DFSS templates for future use
26. EATS PROCESS FMEA IMPROVEMENTS
Item # PROCESS FAILURE MODE Part # Improvement
Reduced
Manual
welding
(Inches)
Cycle Time
reduciton
(min)
1
Part profile issues causing fitting problems in
production
21290535
Redesigned shape/profile to match
the tube profile
12 15
2 SCR bracket does not fit, causing 6" NVA welding 21293745
Improved profile to match the tube
profile
6 5
3
Part profile issues causing 8"x 1/2" non-value add
manual welding
21294709 same as abobe 8 10
4 Part does not fit, have to grind and weld part 21602557 same as abobe 10 20
5 DPF channel manually welded after robot 828/829/830/832
Transferred welding onto robot.
Reduced cycle time by 20min
18 20
35. WEEK OF DATE EATS PRODUCTION SCHEDULE
START TIME= 7:00
WORK ORDER
PART
NUMBER
QTY TAKING COMPLETED ROBOT 7 COMPLETED JOINING COMPLETED
PAINT LINE
COMPLETED
FG
1ST CART 1ST CART 1ST CART 1ST CART 4PCS
WOXXXXXX 222148XX 4PCS 9:00 11:30 14:00 17:00 17:00
2ND CART 2ND CART 2ND CART 2ND CART 8pcs
8PCS 11:00 14;00 16:30 19:30 19:30
3RD CART 3RD CART 3RD CART 3RD CART 12PCS
12PCS 13:00 17:30 20:00 22:30 22:30
1 CART= 4PCS EVERY 3HRS
36. Transformed Batch & Queue production into
Lean 1pc Continuous Flow with PULL SYSTEM
Redesigned critical to quality C2Q components
& obtained VOLVO approval
Redesigned tacking fixtures, and robot welding
fixtures
Increased Robot welding utilization from 30%
to 97% , with consistent parts eliminating
rework and manual welding
Implemented in-process QUALITY inspection
Developed Master Sample for welding Quality
purposes visible to everyone on the floor
45. We maintained ZERO WO LATES (since April 21, 2014)
We reduced quality reject rate from 30% down to 3%
We reduced total lead time from 4.5 down to < 2 days
We reduced total cycle time from 3Hrs to 0.7Hrs/pc
We reduced our WIP from 33 pcs to 12pcs in < 2 weeks
We achieved our project objectives in a 3 month period, ,
something that was considered not possible before !!
46. Increased Productivity from 8-12/day = 40-60/week, 20
units/week
1000 units/year , Annual volume = 3000 units/year
Sale price = $1500/pc
Increased Revenue = $1500*1000pcs = $1.5MIl/year
66% GM = $1MIl GROSS MARGIN
Old cost/unit = $490/pc
New cost/unit=$342/pc=>=$150/unit savings x 3000pcs=
$450K
$1.5Mil – ($342 x 3000)= $512K
Total savings= $450K + $512K=
$960K