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P 31
OTS-3000 User Manual – FAQ
F A Q
1. Paints and Coatings Type
Ans: Nearly all solvent-borne and waterborne coatings can be applied by OTS-3000. A coating’s
impedance should be between 20M ohm to 30 M ohm obtain an appropriate charge. Changes
can be made to make a coating more conductive, including solvent additions, changes in
solvent composition, and use of polar solvents. Viscosity corrections may also need to be
made to ensure coating droplets are fine enough. The conductivity of the paint, or its capacity
to carry an electrical charge, is an important factor in electrostatic spraying. The paint to be
used should be conductive enough to accept the negative charge from the spray gun but
not so conductive that the charged paint tracks back to ground through the paint system
supply. Water-borne and metallic coatings tend to be highly conductive, while solvent borne
coatings tend to be non-conductive. Paints can be modified with polar solvent ( E.g., alcohols
and ketones) or conductive pigments (e.g., metallic pigments) to increase their conductivity.
Likewise, highly conductive coatings can be modified to prevent the electrical charges from
shorting to ground and leaving the paint uncharged. Paint throughput and coating quality are
influenced by viscosity, surface tension, conductivity, solvent evaporation, etc., by the type
of atomizing equipment, and by the way the equipment is controlled. An electrostatic spray
system should balance paint particle velocity and electrostatic voltage to optimize coating
transfer efficiency.
Solvent-borne: Coatings in which VOCs are the major solvent or dispersant.
Polar: Descriptive of molecules where the atoms and their electrons and nuclei are arranged so that
one end of the molecule has a positive electrical charge and the other end of the molecule
has a negative electrical charge. The greater the distance between the two charged ends,
the higher the polarity. Polar molecules ionize in solution and impart electrical conductivity.
Viscosity:
The property of a fluid whereby it tends to resist relative motion within itself. A thick
liquid such as syrup has a high viscosity. Viscosity is often measured using an efflux-type
cup, which gives the time required for a given quantity of paint to flow through a hole in the
bottom of the metal cup at a given temperature (See Zahn Cup).
CONDUCTIVITY PROMOTER or pigments:
Some type of coatings and paints for reference .
Paints Type Application
Melamine Coatings Car ,Boat ,Metal
Polyester-melamine Furniture,electrical equipment, car wheel, bicycle,
Computer case
Polypropylene Coatings Wooden, Furniture
Poly Urethane Coatings Motorcycle ,bicycle , Car, medical equipment , Machine , Car,
Polyurethane Coatings Wooden, Metal , Leather, Plastic,Furniture
NC Lacquer Wooden, Metal,Furniture
Metallic luster Coatings Wooden, Metal,Furniture
Water Soluble Paint Wooden, Metal,Furniture