From ideal of saving material to be electrostatic spray gun
Since there have a spray gun technology for surface coating at 19th century. This is the first step of revolution of surface coating color and it is the big step of technology development in next process. As thier have 2 times world war, especially the 2nd world war, the spray is used regularly inn weapon industry in order to pace up the production capacity and deliver all armament into battlefield as quick as they can. When the world war was finished, the spray gun technology is still developed in order to apply with other industry.
Even the spray gun can support to finish surface coating quicker and also increase the production capacity significanntly than brushing. There have a question that how to reduce the quantity of paint but get the same result because some atomized paint haven't attached on workpiece surface and be spreaded without proper direction and face the over spray problem. For mass production that the workpiece is the same unit for whole production line, the soution for paint spray that sovle the problem of unattached surface by atomized paint is electrostatic spray gun.
The movement of electric charge by paint into electric field and be absorbed to workpiece
Related factor of Electric Spray Gun
Even-though the electrostatic gun has advantage of saving material by wrap around effect but it is not for all kind of material paint. Not only spray gun, the material paint must have a criteria of electrostatic gun compatible, the factor of electrostatic compatible is paint resistivity. This factor determine the material paint that it can be applied with electrostatic gun or not. WAGNER electrostatic gun for solvent-based paint determine the paint resistivity at more than 150 Kohm. This factor similar to net that it will catch the electric charge and bring paint out from spray gun. If the paint does not have paint resistivity enough, it seem like there is no net in paint and then when paint is atomized out from nozzle, no wrap around effect by electric charge.
In other hand, the paint quality and the speed of transferring into electrode will be effect to paint status in following as below;
The large particle of paint: Electrostatic has a few effect to this paint so the wrap around performance will be lower and the paint resistivity is low. Therefore, this paint has high volume of electric conductive. When use electrostatic gun for this paint, it is required to use additional accessories such as coil tube for low resistivity paint that it support to add electric charge into paint. For example, metallic paint, pearl paint and paint which has metal powder mix in paint. For water-based paint that the particle larger than solvent-based paint will be use with different electrostatic gun series and separate into another categories for water-based paint section.
The small particle paint. This paint has high paint resistivity rate and electric charge will be added simply. It is more regular used by electrostatic gun. This paint does not required any additional accessories item.
However, every paint which is used with electrostatic gun must be created and compatible for electrostatic system. If paint is not built for electrostatic painting system. When you use this kind of paint, the performance is not different from electrostatic gun.
Electrostatic gun. The revolution of surface coating
The ideal of electrostatic application for surface coating is occurred in decade of 50's or after world war 2. The industry need to be restored quickly and this ideal is applied intentionally to save the material usage quantity whether in that time or present day. Many of industry factory require electrostatic spray gun for large material paint consumption.
The basis of this spray gun, using the different polarity. Spray gun add electric charge into paint as negative polarity and spray out into workpiece which attached by holder with ground that the workpiece can absorb paint automatically because ground effect from holder is transfer to workpiece then paint and workpiece is different polarity and will be wrap around. Therefore, it is support to reduce material watse in significant amount. (Decrease around 30% as compare with ordinary spray gun) Every atomized paint will be absorbed and wrap around workpiece so it also prevent the over spray effect.
Example of Paint Resistivity
Electric charge is added into paint with suitable paint resistant value
Electric charge throughout paint as the paint resistant value is too low
The workpiece is risk to face faraday cage
Application with complex structure of workpiece
As the advantage of electrostatic spray gun, it is developed by generation to generation and also be applied for other type of work which is not only for mass production and not only air spray gun, there have another type that can be use with high pressure spray paint.
When you face the complex structure of workpiece, the problem of faraday cage will be occurred because some area of workpiece is coated already and some area is needed to be re-painting. Paint atomized can be reached to surface because there have negative polarity on some surface already and push back the new paint atomized. (Cause of the same polarity) This problem has the solution. As there have control unit which always sell with electrostatic gun 1-1 unit. (1 gun and 1 control unit) This control unit can adjust the high voltage level and air pressure to be suitable value and compensate each value to bring paint into workpiece surface. The control unit of solvent-based paint and water-based paint is not the same unit.
However, you can not ignore another factor such as the paint booth, this paint booth require the grounding system following the safety standard and in order to create the electric field in painting area. If there is not grounding system, electrostatic gun can not be performed following their specification.
Control Unit for Electrostatic Gun
(Solvent-Based Paint Series)
For further information of electrostatic gun basis, you can see more details in following as below;
Technical Data of Electrostatic Gun by Categories
The electrostatic gun for solvent-based paint and water-based paint is similar only the gun body but the internal structure, spare-part, control unit and application is a hugh different and can not be used for the same application. To make it simply understanding and clearly in order choose correctly, this spray gun will be presented separatly and the material application will be identified in each series.
(Please click "Details" for further information)
Spray gun, Control unit and related accessories for solvent-based paint only. This is the regular series for large industry such as automotive, part, component, electronic device and other heavy industries. The information are following as below;
Electrostatic Air Spray gun GM5000EA
Electrostatic Air Coat (Air Mix) Spray gun GM5000EAC
Control Unit VM5000
Related Accessories for Solvent-based paint series
It is a huge different from solvent-based series. The internal structure and application is specific for water-based paint only because this paint has conductivity status higher than solvent-based paint so it is strongly required for plastic insulation booth in order to keep feeding unit and transferring paint section to avoid the painter touch this area. The control unit is different from solvent-based paint. The information are following as below;
Electrostatic Air Spray Gun GM5020EAW
Electrostatic Air Coat (Air Mix) Spray Gun GM5020EAWC
Control Unit VM5020WA for Water-based paint
Plastic Insulation Booth Aqua Coat for water-based application
Related Accessories with water-based electrostatic Spray Gun