●In a Corona gun the high voltage electrode generates a big
quantity of ions. Only a few ions charge the powder particles,
the others remain free and are attracted by the part surface.

●

The accumulation of ions on the part surface can produce“orange peel effect” and “back-ionization” problems.

●SuperCorona discharges the excessive free ions andsignificantly improves the surface quality.

●

The free ions generate a strong electric field that makes it
more difficult for powder to penetrate into corners andrecesses (Faraday Cage Effect).

●

SuperCorona discharges the excessive free ions andfacilitates the powder penetration.

ControlledPowder Charging

Improved
Surface Quality© GemaSwitzerland
GmbHEN-Feb-24- All rights reserved.
© All rights
reserved

SuperCorona, the Best Solution for Smooth Surfaces

Increased Powder
Penetration

●

Most common powders need the gun to deliver a high levelof charging current (10 to 100 µA).

●

Special powders (metallic, enamel, two coat / one firepowders) are high-chargeable and require the guns to delivera lower and well controlled charging current, below
10 µA.

●Gema Precise Charge Control (PCC technology) allows tocontrol powder charging very precisely, with a resolution of
only 0.5 µA until 10 µA.

●This is the ideal solution to provide the right amount ofcharges and achieve a much better application quality.

PrecisePowder Charging

Improved
Surface Quality

Powder type A

Standard current control
Powder type B

PCC- Mode

Ideal forSpecial Powders© GemaSwitzerland
GmbH- All
rightsreserved.
© GemaSwitzerland
GmbH- Allrightsreserved.

PCC Mode, the Perfect Control on Powder Charging

● Today’s powder coaters need to use awide variety of powders, with different
formulations and characteristics.
● Only the ideal charging of eachpowder ensures perfect coating
results.
● Gema is offering innovativetechnologies to achieve the ideal
charging of even challenging powders
like structured and metallic powders,porcelain enamel,
2-coats 1-fire powders, etc.

© Gema Switzerland GmbH - All rights reserved.

Electrostatic Powder Coating3• In a corona gun the high voltage
electrode generates a big quantityof air ions
• Only part of the air ions reallycharge the powder particles, theother ions remain free and areattracted by the surface to coat(which is grounded).
• The accumulation of free ions on
the surface to coat can produce an
uneven powder layer and the socalled “orange peel effect” or“back-ionization” problems.

© Gema Switzerland GmbH - All rights reserved.

Corona Charging: How Does it Work?

4

● SuperCorona is an add-on
accessory that can be easily
mounted on any Gema gun.
● It can significantly improvesurface quality and powder
penetration, both for manualand for automatic guns.
● It can be removed for thepowders that don’t need it.

© Gema Switzerland GmbH - All rights reserved.

SuperCorona: How Does it Work?

5

Traditional Charging:less precise, low resolution

Precise Charge Control (PCC):
more precise, high resolution●

In traditional corona guns the regulations of
the electrostatic parameters are not very
precise.

●Gema has developed PCC, an electronic
technology that allows more precise
electrostatic regulations.

●

The actual value of the charging current canvary within a significant range in comparison
to the set value.

●The electrostatic parameters are kept within
a much smaller variation band in comparison
to the set values●The parameters can be set only with arelatively large resolution (1 µA / 1 kV ormore)●The parameters can be set with a smaller
resolution (0.5 µA) and controlled much
more precisely© Gema Switzerland GmbH - All rights reserved.

Precise Charge Control: How Does it Work?

6

● Precise Charge Control (PCC) mode is automatically activatedwhen Current is set below 10 μA.
● The OptiSpray display showing the High Voltage and Current control
turns red when PCC mode activates.

© Gema Switzerland GmbH - All rights reserved.

Precise Charge Control Activation7

● Orange peel effect and back-ionization can happen when the guns are
emitting too much charges. These charges accumulate on the surface to coatand create visual defects.
● PCC technology and SuperCorona help to optimize the amount of charges
that are needed by each powder.
Resultso much nicer surfaces,o even with special powders,© Gema Switzerland GmbH - All rights reserved.

Improved Surface Qualityo even when high film thicknesses are needed8

●Powder penetration into corners is difficult
because of the Faraday Cage effect.

●The electric field (created by the electrodeand by the charges) pushes powder
particles to the edges of the object, while
the electric field is not getting into thecorners.

●PCC technology and SuperCorona
reduce the electric field generated by thefree ions.

Results© Gema Switzerland GmbH - All rights reserved.

Improved Powder Penetrationo Easier penetration into corners

o More regular powder distributiono Powder savings

9