The development of the perfect spray jet: principles and influencing factors

When painting, the spray jet is the central element. It transports the paint from the nozzle to the surface and is crucial to the quality and uniformity of the result. But what exactly influences the shape and quality of the spray jet? In this article, we explain the main factors that influence the spray jet and what you should consider to achieve optimal painting results.

1. The role of nozzle geometry

The geometry of the nozzles – both the air and paint nozzles – plays a key role in the formation of the spray fan. The internal and external shape of the nozzles influences the flow conditions and thus the way the material is atomised. Carefully designed nozzle geometry produces a consistent, stable spray that applies the paint in a controlled and precise manner to the surface.

2. air pressure and material flow: the balance is crucial

The air pressure inside the nozzle and the material flow must be perfectly balanced. High air pressure increases the speed of the paint as it comes out of the nozzle and helps with atomisation. However, if the air pressure is too high, it can deform the spray jet by constricting it in the middle. It is therefore important to strike the right balance: the air pressure should be just high enough for the material to be atomised into fine droplets and applied evenly, without the jet being deformed too much.

3. influence of the air cap: the shape of the spray jet

The so-called horn air – the additional air that escapes from the side of the nozzle – forms the spray jet into an ellipse or a round jet. This shaping is particularly important when painting complex or larger surfaces. The higher the fan air energy (i.e. air pressure and air volume), the more the jet is stretched sideways and shaped into an ellipse. For detailed work, the jet can also remain in a round jet through lower fan air energy, which allows for greater precision.

4. Spray distance: The correct distance to the surface

The distance between the spray gun and the surface to be painted is crucial. Too great a distance results in a wider, less concentrated spray jet, which reduces the layer thickness and leads to uneven results. If the distance is too small, there is a risk that the paint will not be distributed evenly and may be applied in too thick a layer. The ideal spraying distance is usually 10-15 cm, but varies depending on the spraying method.

5. The importance of the viscosity of the material

The viscosity of the paint also affects the shape of the spray jet. A paint that is too viscous is difficult to atomise at low air pressures, while a material that is too thin is over-atomised at high air pressures. Adjusting the viscosity, for example by thinning, is important to achieve the desired jet shape and atomisation.

Conclusion: precision in every detail

Achieving the perfect spray pattern requires the interplay of many factors: the geometry of the nozzle, the balance of air pressure and material flow, the control of the horn air and the optimum spraying distance. By precisely coordinating these variables, you not only achieve a uniform and aesthetically pleasing painting result, but also work more efficiently and in a more environmentally friendly manner.

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