" " wisno wood furniture finishing: Air spray gun for furniture finishing

Thursday, October 29, 2009

Air spray gun for furniture finishing

Air spray gun or air conventional spray gun is a type of spray gun which was first discovered and used in the finishing materials application. It is the initial basis of the spraying equipment before the other type were developed. In this spray gun, the finishing materials is flowed together with compressed air through a room called nozzle. Nozzle is the spray gun part that is designed to let the liquid (material finishing) flows in very high speed. The quick flow of the finishing material and the air flow make the atomization occurs. And then the atomized finishing material can be directed by the gun to coat the surface needed. 
Atomization is the condition when a liquid material becomes a diffused of small particles material to be like fog. In the spraying process, the atomized material then is directed and layered to the wood surface. The quality of atomization determine the layering result. The perfect atomization is producing the excellent layering result, the even and material layer. The air spray gun gives the best atomization of the finishing material and will produce the best result in layering materials. This equipment give the smooth, uniform surface and most flexible in use with fully adjustment. The air spray normally work at 4 bar (58.8 psi) air pressure with about 12 c.f.m volume of compressed air.  The air pressure depends on the viscosity material that was applied; the higher viscosity of the material require the higher air pressure, while low viscosity may need lower air pressure.
The advantages of this air spray gun are: very flexible in use, produces excellent atomization, produce very smooth and uniform film, equipment is relatively simple, inexpensive and has high flexibility to be adjusted according to the application requirements. Air spray gun can be used for almost all kind of finishing materials applications. The air spray gun is very flexible and fully adjustable. The operator can adjust the air pressure, the volume of material, the spread width of the material and also the direct of the spread of material. This equipment has high flexibility to be adjusted to handle the variation in the production process. It is more suitable to do the production with varies products with the small to medium volume production.




Meanwhile, the biggest disadvantages of the air spray gun is his low transfer efficiency material. The transfer efficiency is range from 30% to 60% depend to the product shape and the operator skill. It means that only about (maximum) 60% of finishing material will layer to the surface, and the rest are become dust spray that mean material lost in the air. The quality of the finishing resulted is highly depend to the application technique. To get the good result in term of the quality and efficiency, the equipment always requires a good skilled operator. In the big volume job when the long man hour is needed, it may lead to the inconsistency result  since of  the operator’s fatigue.



The atomization finishing material in the air spray gun


To increase the efficiency of transferring material at the air spray, we need to keep the air pressure low. The air pressure used in application using air spray gun should be set in the position at the lowest pressure but is still enough to do the atomization of finishing material perfectly. The higher pressure of the air pressure will increase the dust spray and lower the efficiency of transfer materials. In the mass production when the work speed is high, the operator who run this gun tend to get inconsistency result due to the fatigue of the operator.

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