Understanding the
Basics of Electrocoat
Kelly Moore
Development Chemist
Overview
Why and When to Use Electrocoat
How Does Electrocoat Work?
Selecting the Right Electrocoat Technology
The Future of Electrocoat
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Why and When to
Use Electrocoat
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Why Use Electrocoat?
Economical
& Efficient
Environmentally
Conscientious
Excellent
Performance
Some
Disadvantages
High transfer efficiency
No or low VOC
Capital expenditure
Precise film build
control
HAPs-free products
available
Controlled uniform film
thickness
100% coverage of
complex parts
Heavy metal-free
products
Coats recessed areas
Minimal waste
discharge
Automated system:
low maintenance and
minimal labor
Dense racking of parts
Non-uniform line
loading
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Improved aesthetics
No runs, drips, or sags
100% coverage
Reduced fire hazards
One or two coat
applications for optimal
performance
Reduced exposure of
workers to hazardous
materials
Epoxy-based for
corrosion, acrylicbased for durability
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Color flexibility
(multiple colors)
Substrate must be
conductive
Bake required
(thermoset)
Selecting the Right Coating System
Performance
Requirements &
Specifications
Substrate &
Part Configuration
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Appearance
Physical properties & durability (adhesion, flexibility, chip
resistance, corrosion resistance, UV resistance, etc.)
Heat limitations
Part complexity and size
Environmental
Factors
Air emissions (VOC/HAPs)
Waste considerations
Economics –
Applied Cost Per
Square Foot
Transfer efficiency
Labor/time requirements
Number of parts to process
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Selecting the Right Coating System
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Liquid
Powder
E-Coat
Colors / Color Changes
Best
Better
Limited
Heat Limitations
Best
Limited
Limited
Environmental Impact
High
Lowest
Low
Transfer Efficiency
Manual Labor
Automated Labor
Limited
High
Good
Better
High
Good
Best
N/A
Best
# Parts Processed
Limited
Limited
Best
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How Does Electrocoat Work?
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What is Electrocoat?
Method of applying a coating which
uses electrical current to deposit
aqueous dispersed resins and
pigments onto a conductive
substrate
• Highly efficient and automated process
• Precipitation of paint particles at
an electrode
• Paint film thickness is regulated
by voltage
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The Deposition Sequence
• Voltage is applied and current flows between electrodes
• Water decomposes at the electrodes
• Paint particles move to the oppositely charged electrode
• Paint particles precipitate
• Paint particles become tightly packed (insulated)
• Deposition stops automatically
The insulating ability of the deposited wet film is what
allows the electrocoat process to coat interior recesses
and cavities – throwpower
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Electrocoat Works Like a Magnet
Cathodic
Anodic
Metal
Substrate
Cathode
Coating film
deposits
with FE++
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Paint
Particles
Anode
Coating film
deposits
without FE++
Electrocoat Process:
The E-Coat Bath
Water-Soluble Bath Blend
Pigment
1-10%
De-Ionized Water
80-90%
Resins
10-15%
Solvent / Additives
1-5%
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Electrocoat Process:
Sample Process Layout
Particle Filter
Racking
Ultrafilter
Flash (Pre-bake)
Oven
Pumps
Power Supply /
Process Control
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Sample Tank Stages
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Cleaning
Pretreatment
Rinsing
E-Coat
Permeate Rinsing
DI Rinsing
Electrocoat Process:
Pretreatment
Pretreatment
Rinse
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Cleans the metal and prepares it for coating
Common to all application technologies
Can be spray or immersion applied
Major contributor to system performance
Type and number of stages dictated by
performance requirements
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Without Pretreatment
With Pretreatment
Electrocoat Process:
The Electrocoat Tank
Filter removes
dirt particles
Ultrafilter produces
permeate for rinsing
and allow for recovery
of paint solids
Rectifier provides DC
electrical charge; heat
exchanger controls bath
temperature
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Electrocoat
Permeate
Rinse
Circulation pumps and eductors
to ensure paint mixing uniformity
Electrocoat tanks may
hold up to 100,000 gallon
Electrocoat Process:
The Post Rinse & Bake Oven
1 - 3 counter-flowing rinses remove
excess paint solids
Smoother finish appearance
Higher operating efficiency
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Used to cure and crosslink the paint film
Bake varies from 180º F - 375º F
depending on electrocoat type
Usually require at least 10 - 20 minutes
metal temperature for full cure
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Equipment Design and Operation:
Selection Criteria
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Capital Expense
Floor Space
Productivity
Maintenance
Racking
of Parts
Process
Flexibility
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Equipment Design and Operation:
Monorail Systems
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• Highest productivity
• Biggest footprint
• Lowest maintenance
• Highest capital expense
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Equipment Design and Operation:
Programmable Hoist System
• Highest flexibility
• Highest maintenance
• Medium to low capital expense
• Lowest productivity
• Smallest floor space
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Equipment Design and Operation:
Square Transfer System
• Lowest capital expense
• Medium to low maintenance
• Smallest floor space
• Medium to high productivity
• Medium flexibility
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Equipment Design and Operation:
Racking vs. Bulk Electrocoat
Racking
• Part configuration / design
• Size / number / density of parts
• Touch points on parts
• Maintenance
2 • Contact points
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Bulk
• Dip-drain / sip-spin
• Shift parts to coat touch points
• Fasteners, other small parts
Equipment Design and Operation:
Relative Comparison of Systems
Indexing System
Square Transfer
Productivity
Lowest
Medium to High
Highest
Maintenance
Highest
Medium to Low
Lowest
Medium to Low
Lowest
Highest
Small
Smallest
Highest
Highest
Medium
Lowest
Capital
Expense
Floor Space
Process
Flexibility
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Monorail
Programmable
Hoist
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Selecting the Right
Electrocoat Technology
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Electrocoat Types
Paint particles positive
Coated parts negative
Paint particles negative
Coated parts positive
Advantages
Advantages
Less iron incorporated
into the film
Economical systems
for interior or moderate
exterior environments
Formulated for
maximum corrosion
resistance and exterior
durability
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Low cure temperatures
Low VOC
Electrocoat Technologies
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Advantages
Disadvantages
Corrosion protection
Chemical resistance
"Tough" film
Poor U.V. resistance (chalks)
Poor color stability (cationic)
Advantages
Disadvantages
Good U.V. resistance
Gloss retention
Good color control
Less corrosion protection
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Electrocoat Technologies
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Benchmark for corrosion &
chemical resistance
Automotive parts, car
bodies, heavy duty trucks,
fasteners
Low-bake applications
Heavy-duty castings,
compressors
High performance,
one-coat applications
UV durability
& detergent resistance
Color control
Color & gloss control for
interior products
Metal office furniture, air
diffusers, range hoods,
tool boxes
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Electrocoat Technologies
Excellent corrosion resistance, especially on sharp edges
Lead-free
HAPs-free
Low VOC
• Agriculture &
construction
• Automotive parts
• Compressors
• Computer parts
• Control arms
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Engine cradles
Heavy duty trucks
Marine engines
Spring clips
Suspension
components
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Switchgear
Torsion bars
Transformers
Truck frames
Electrocoat Technologies
Low cure: 180-225º F cure capability
Fully thermoset
Hardness/corrosion resistance similar to higher cure coatings
Lead and chrome-free
Good throwpower
More iron in film, which limits performance
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Agricultural implements
Assemblies fork lifts
Compressors
Concrete
reinforcements
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Construction equipment
Engines & motors
Seat tracks
Heavy duty castings
Military aircraft
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Pipe
Plated plastics
Structural steel
Aluminum substrates
Galvanized substrates
Electrocoat Technologies
High performance with both high- and low-gloss capability
Color control and can be formulated as a clear
Can be formulated for optimum corrosion or durability
HAPS compliant
Topcoat-able (should be tested)
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Agricultural implements
Air conditioners
Aluminum extrusions
Appliances
Brass, plated substrates
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Heavy duty equipment
Lawn & garden
Refrigeration
Switchgear
Transformers
• Welding equipment
• Wheels
Electrocoat Technologies
Excellent appearance, gloss, and color control
Interior & mild exterior use
Reduced emissions
No/low solvent additions
No heavy metals
More iron in film, which limits performance
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Air conditioners
Air diffusers
Furnaces
Hangers
Metal office furniture
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Metal strapping
Range hoods
Toolboxes
Wire screen
Electrocoat Applications
Electrocoat is the final finish
Two electrocoat layers for high performance
Electrocoat + a liquid or powder topcoat produces
exceptional performance properties
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Electrocoat Applications
Cathodic epoxy basecoat ensures excellent
corrosion protection
Cathodic acrylic primer-surfacer provides an exterior
durable finish and cost-effective topcoat
Corrosion protection, chip resistance, UV durability
No heavy metals
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Agricultural implements
Aluminum trim
Condensing coils
Generator housings
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• Marine engines
• Transformers
Electrocoat Applications
Cathodic epoxy basecoat ensures excellent
corrosion protection
Liquid or powder topcoat allows for combination of corrosion
resistance and desirable appearance
• Automotive
• High-end appliances
• Sports and recreation
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Summary
Corrosion Resistance
Auto Parts
Low Cure
Coat Hangers • Shopping Carts
UV Resistance
Washers & Dryers • Lawn & Garden • Agricultural Equipment
Decorative
Consumer Electronics • Jewelry
Severe Environments
Generators • Transformers
Performance + Appearance
Automotive • Appliances • Sports and Recreation
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Questions?
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Thank You
Kelly Moore
Development Chemist
PPG Industrial Coatings
1-800-774-3262
[email protected]
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