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Transcript of instrumental Color Measurement For Process Control · Global Paint & Polymers Center G P P C...
G P P C Global Paint & Polymers Center
Instrumental Color Measurement for Process Control
Lisa L. Shaw GM Global Paint & Polymers
April 2011
G P P C Global Paint & Polymers Center
Perceptual Quality
Improve Surface
Structure (Orange
Peel)
Improve Color
Harmony
Improve Secondary
Surface Appearance
Improve Exposed Sealer
Appearance
Evaluate Color
Palette
“Best in Segment” Strategy: Quality Pillars
Pillar
Strategic Tasks
Init
ial Q
ual
ity
One ME Global MEPaint and Polymers “Best in Segment”
Pe
rce
ptu
al Q
ual
ity
Lon
g Te
rm Q
ual
ity
Po
lym
ers
an
d
Ad
d-O
n P
arts
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Foundation for Process Control
Need for Objective Assessment that can be Conducted in Paint Shop Lighting
One Fascia Supplier Supplies Multiple Plants
Why Instrumental Color Measurement?
Assembly Plant 1
BC/CC System Supplier A
WBBC/2KCC
Assembly Plant 2
BC/CC System Supplier B
WBBC/2KCC
Assembly Plant 3
BC/CC System Supplier B
WBBC/1KCC
Fascia Supplier 1 BC/CC System
Supplier A SBBC/2KCC
BC/CC System Supplier B
WBBC/2KCC
Fascia Supplier 2
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Objective Instrumental Measurement: Color Harmony
Gage R&R Validated
Multi-Angle Color Measurement
Metallic Impact Characterized by Sparkle and Graininess
Objective Data for Match to Standard or Adjacent Panel Harmony
Obtain color harmony using tool for process control.
Multi-angle Color Measurement
Sparkle and Graininess Evaluation
Chromatic:
2*
2*
2*
2'
+
+
=
gggg
g
HHCCL
L Sg
DH
Sg
DC
gSg
DLDE
g
+-+=
+-=
+=
ggg
g
gg
2120.014.07.0;7.0max
4235048070max
5.3115.0
LCS
L g.C g.;.S
LS
g
g
g
H
C
L
2
*
2
*
2
*2'
+
+
=
gggg
gbbaaLL Sg
Db
Sg
Da
Sg
DLDE
Non-chromatic:
=
=
+=
7.0
7.0
5.3115.0
g
b
a
L
S
S
LSg
g
gg
Chromatic: C* 18 or C* 10 and L* 27
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Color Risk: Likelihood of a Color to Change Sparkle, Grain, or Hue Due to Viewing Angle
Volt Color Code Risk Capability
Black 41 / GBA Low
Crystal Claret Tintcoat 89 / GBE Medium
Switchblade Silver Metallic 17 / GAN Medium
Urban Fresh Tricoat 16 / GLC High
White Diamond Tricoat 98 / GBN High
Cyber Gray Metallic 57 GBV High
COLOR PALETTE
PRODUCT DESIGN
COLOR HARMONY
APPLICATION METHOD + + =
LOW: Non-Metallic or Dark Metallic Color with Minimal Travel & No Hue Shift
MEDIUM: Light to Medium Metallic Color with Travel and No Hue Shift
HIGH: Light to Medium Metallic Color with High Travel and Hue Shift
Poor Color
Harmony
Example
Fascia Cut-Line Color Category
Low Medium High
DES
IGN
All Vertical 90 Green Yellow Red
Short Verticals & “Z” Joints
Green Yellow Red
Horizontal Green Green Yellow
Horizontal with Break
Green Green Green
Design = ( Cut Line Gap Character Angle Interface )
Design = ( Cut Line Gap Character Angle Interface )
Angle Interface
Color Category
Low Medium High
DES
IGN
< 4 Angle Green Yellow Red
> 4 Angle Green Red Red
COLOR PALETTE
PRODUCT DESIGN
COLOR HARMONY
APPLICATION METHOD + + =
Service Bulletin: 2010 Chevrolet Camaro Information on Door and Quarter Panel Paint Appearance Background
Paint on Doors May Appear as a Different Shade than Quarter Panels Varies based on Viewing Angle and Light Conditions More Apparent with Certain Colors
Design Intent Door to Quarter Panel Angle Match is the Design Intent Wildfire Metallic (High Harmony Risk Color) Panels Demonstrate Impact of
Angle on Apparent Color
STANDARD STANDARD STANDARD
Flat Panel with Standard Indicating Color Consistency
Panel with Crease on Right Side Creates an Angle Similar to the Camaro Door-Quarter Interface
Standard Repositioned to the Right Side of the Panel Shifts Along with the Angled Side
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Instrumental Color Process Control 3 Segments
1. Batch 2. Painted Body 3. Color Harmony
1st Degree of control. Reduce batch to batch variation to minimize
color impact.
In paint shop control – daily measurement to
identify processing variations and maintain
consistency.
Measurement of assembled product for match point data and
visual correlation.
BykMac Output Component to
Component (Body to Fascia) Batch & Component to
Standard
Total Color Difference dSE
dSt Effect
Sparkle Graininess
25, 45, 75 -15, 15, 25, 45, 75, 110
dEt Color Difference
Angle Independent
Diffuse Light Bright Light DL
Da
Db
DL
DC
Dh
Light to Dark
Chroma (Saturation)
Hue
Sa Sparkle Area
Si Sparkle Intensity
High Sparkle
Low Sparkle
High Graininess
Low Graininess
G Graininess (Fine vs. Grainy Pattern)
+ - + - + -
Supports Benchmarking & Monthly Color Harmony
Reviews
Supports Paint Shop and Paint Supplier Process Control
Measurement of Color: Color Systems for Automotive Exterior Applications
DIN 6175-2 System
DE DIN Scales
Developed by European OEM’s
Based on Metallics
Good DE DIN Visual Correlation
Weighting Factors
- Angle (g)
- Application (g)
- Color (S)
Chromatic:
2*
2*
2*
2'
+
+
=
gggg
g
HHCCL
L Sg
DH
Sg
DC
gSg
DLDE
g
+-+=
+-=
+=
ggg
g
gg
2120.014.07.0;7.0max
4235048070max
5.3115.0
LCS
L g.C g.;.S
LS
g
g
g
H
C
L
2
*
2
*
2
*2'
+
+
=
gggg
gbbaaLL Sg
Db
Sg
Da
Sg
DLDE
Non-chromatic:
=
=
+=
7.0
7.0
5.3115.0
g
b
a
L
S
S
LSg
g
gg
Chromatic: C* 18 or C* 10 and L* 27
1.7
1
gDa
gDb
DIN 6175-2 System Allows Use of Red Yellow Green
Zones with a Single Tolerance
DEp 1.7 STOP1.0 < D Ep ≤ 1.7 Evaluate
D Ep ≤ 1.0 GO
Application Factors: gL ga gb gC gHNormalized Tolerance
Paint Batch Application 1.0 1.0 1.0 1.0 1.0 DEC = 1.0
Paint Line Body 2.0 1.2 1.2 1.8 1.2 DEP = 1.0
Repair Line 2.0 1.2 1.2 1.8 1.2 DEP = 1.5
Repair Line with Gap 2.0 1.2 1.2 1.8 1.2 DEP = 3.0
DEp
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Process Control Time Allocation
Data Collection Batch
Painted Bodies
Full Vehicles
Data Analysis Trend Charting
Individual vehicle tracking
Scorecards
25%
75%
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Data Analysis
Objective: • Use process control charts to track changes and
drive continuous improvement • Not a Go/No Go Method.
Method • Track Total Color, dE, Total Effect, dL, da, db
averages over time. • Look at individual vehicle data for visual
correlation.
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Data Analysis
Use Data to Excel to extract useful data for charting.
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What Has Worked Well
Measurement for Process Control
Trend charting using Excel
Ease of use for operators – software and equipment
Repeatability of measurements
Visual correlation on many colors
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Success Story
Detected a special-cause variation in batch. Re-routed vehicles to prevent passing issue into production process.
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Opportunities for Improvement
Visual correlation for interference pigments and tri-coats.
Difficulty correlating same colors between plants based on technology and formulation.
Charting capabilities in software.
Speed of software for download and data analysis.
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Visually acceptable to standard.
Visually acceptable to standard.
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G P P C Global Paint & Polymers Center
G P P C Global Paint & Polymers Center
Understanding DIN6175
Internal tolerances may not suit 100% of colors • “False Feel Good” - Solids
• “False Reaction Required” – some interference pigments
Partner with suppliers to identify “trouble” colors for DIN6175.
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Partnering with Suppliers
Add-on part suppliers, paint suppliers.
Integrate common equipment and capabilities across supply base.
Data-sharing partnership to improve color harmony.
Variation reduction and process control.
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Partnering with Suppliers
dE15 dE25 dE45 dE75 dE110
dE
dE Angle
Plant A and Supplier B dE Overlap and Min/Max Zones
Overlap Min
Max
Min
Overlap Max
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dL*15 dL*25 dL*45 dL*75 dL*110
dL*
dL Angle
Plant A and Supplier B dL* Overlap and Min/Max Zones
Overlap Min
Max
Min
Overlap Max
da*15 da*25 da*45 da*75 da*110
da*
da Angle
Plant A and Supplier B da* Overlap and Min/Max Zones
Overlap Min
Max
Min
Overlap Max
db*15 db*25 db*45 db*75 db*110
db
*
db Angle
Plant A and Supplier B db* Overlap and Min/Max Zones
Overlap Min
Max
Min
Overlap Max
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Work with suppliers to further understand DIN 6175
Continue to improve visual correlation for interference and tri-coat paints.
Integrate color process control across supply base
Include color measurement from beginning stages of color development
Color Measurement: Future Opportunities