Electrophoretic application of paint.

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Electrophoretic application of paint.
Peter Hope, FIMF LVH Coatings Ltd.
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Electrophoretic painting what is it?

• Target surface must be electrically conductive.
• Target is immersed in the specially formulated
  water-based paint bath and a d.c. voltage is
  applied.
• Paint solids are electrodeposited conformally
  over conductive surfaces.
• Similar to electroplating but depositing a
  paint instead of a metal.

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Why would you consider the electrophoretic
application method?

• Your (conductive) widget is a complicated shape
  that is difficult to paint any other way.
• Complete and controlled surface coverage is
  necessary for decoration and/or performance.

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It must be Electrophoretic!
The paint on this car stops rust.
1960s American cars were first to have
electrophoretic paint as an anti-corrosion primer.
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BIG - during 2003, 42 million vehicles
manufactured world wide requiring an estimated
42000 metric tonnes of electrophoretic paint
solids.
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Fibre length 6mm Fibre radius 3.5 microns Tip
radius 50nm
SMALL - 2000 to 2008 Electron microscope probes
and other micro-research structures require less
than 1gm of electrophoretic paint solids!
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SMALL items - but large numbers Spectacle
frames.
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Door and window hardware.
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various other complex-shaped consumer items..
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and difficult-to-paint industrial components.
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..Automotive functional parts
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.Automotive trim parts
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..Specialist architectural.
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Process advantages.

• Very suitable for painting complicated shaped
  items.
• High productivity especially when automated.
• High material utilisation/low wastage compared to
  other application methods such as spraying.

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Electrophoretic vs. Spraying Overspray
wastes material. Can be labour Intensive. Rack
/support gets coated also waste of material.
Electrophoretic application enables very high
transfer efficiency.
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Simple electrophoretic paint line schematic.
Drag-out rinsed off with clean permeate
Unpainted part
Painted part drag-out
Painted part
From pre-treatment
To oven
Paint bath
Permeate Drag-out
Raw permeate
UF
Clean permeate
I E
Using ultrafiltration (UF) rinse/reclaim closed
loop - nearly 100 material utilisation with
minimum waste.
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Appropriateness of use.( disadvantages)

• Mainly suitable for large continuous production
  quantities of a single finish.
• Requires investment in specialised plant and
  equipment.

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Continuous RD produces an increasing number
of Electrophoretic painting capabilities..
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Equipment/installation.

• Basic requirements are a coating bath, rectifier,
  filtration, purified water and a curing method.
• Bath size and installation footprint depends upon
  the size and production rate requirement of the
  widget.
• Bath sizes vary from less than 100 litres to more
  than 500000 litres.
• Easily incorporated into electroplating lines

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Curing methods.

• Thermal curing is possible from about 80C up to
  about 190C. Thermal curing below about 120C tends
  to limit the potential for high chemical
  resistance.
• Both hot air and Infra-Red techniques are used
  for thermal curing.
• UV curing systems are available that can be
  processed below 80C.

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Hardness, wear resistance and friction control.

• Hardness and wear resistance can now be
  comparable with brass and aluminium by using
  nanocomposite technology.
• Incorporation of various dry film lubricants
  provides highly wear resistant low friction
  coatings.

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Corrosion protection.

• Electrophoretic paints can provide all-over
  corrosion protection for most metals.
• Good compatibility with most traditional and
  new anti-corrosive pre-treatments.
• Certain instances do not require the use of any
  separate anti-corrosive treatment notably
  anodic electrophoretics over some aluminium
  alloys.

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Chemical resistance.

• Different resin systems are available that will
  cover many industrial requirements.
• Automotive grades based on epoxies have
  intrinsically high chemical resistance.

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Resistance to weathering.

• The main problems are resin breakdown and colour
  change due to the effects of UV radiation in
  sunlight.
• Exterior durable resin systems are available with
  compatible fade-resistant colourants as required.

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Decoration.

• Electrophoretics can be coloured in a wide
  variety of effects similar to conventional
  paints. Even metallic or pearlescent effects
  are possible to some extent.
• A characteristic is the incorporation of
  transparent colourants to give coloured metal
  effects over reflective white substrates such
  as bright nickel or polished zinc and aluminium.
• Gloss can be controlled independently of colour
  effect.

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Other capabilities.

• Photoresists 2D or 3D surface imaging for
  printed circuits, nameplates and chemical
  milling.
• Conductive coatings - grounding, shielding,
  anti-static and multi-layer electrophoretic
  coating.
• Something else? Ask and you might get!

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Electrophoretic summary.

• Mature and accessible industrial painting
  process.
• Especially appropriate for complicated shapes in
  high production quantities.
• Very wide capabilities general purpose to
  highly specialised.
• Ease of automation minimises unit costs by high
  productivity.
• High material utilisation with minimal waste.

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Thank you for your attention!