With a wide range of spray technologies and spraying systems, it is hard to understand the differences and advantages between them. We will try to help you to get to know the types of paint systems you should take into account when starting a new project.
Liquid feeding methods for spray finishing
• Suction feeding: by creating a venturi in the siphon tube placed in the chamber, the material is extracted from the liquid container.
• Gravity Feed: as the name suggests, the material is gravity fed from the container placed above the spray gun.
• Pressurized Feed: material is pressure fed to spray guns through a pressure pot or remote pot. Pressure is applied by air in the pot to force the material up through the hoses to spray the nozzle.
The paint is atomized by the high volume, high pressure air bombardment paint that exits the liquid nozzle in a cloudy spray pattern. A solid layer of material is obtained by repainting several times in various directions.
• Very good results were obtained
• Good controllability
• You can use a small amount of material
• Low transfer efficiency: 60% waste, i.e. overspray
• Slow application rate
• Can only spray low viscosity paints
HVLP (High Volume Low Pressure) / Compliant
Liquid feeding methods
The material is fed into the spray gun via a pressure vessel or pressure bottle (as described in the air jet section).
The paint is atomized with a large volume of low pressure (approximately 6 psi) air that pumps the paint supplied by the spray gun fluid nozzle.
• This spray treatment system is approximately 80% efficient compared to conventional air spraying
• Will spare a good paint
• Much cleaner application, therefore safer working environment and less maintenance of the spray booth
• Slow application rate
• Only low viscosity materials can be sprayed
How does the airless spray work?
The material is sucked and sucked into the pump, then compressed hydraulically or pneumatically at high pressure by means of a 0-5600psi double-acting pump or a diaphragm unit, depending on the characteristic of the pump. The material is then forced through the tip of a spray nozzle that is 9 to 55,000 in size depending on the material applied, which creates the atomized spray pattern.
• Quick application: from 200 to 250 M² / hour
• Good transfer efficiency
• Application of thick coatings
• High film structure
• Inadequate control
• Lower surface quality than atomized air
AIRCOAT / AIR ASSISTED AIRLESS / AIRMIX
How does Airless Airless work?
It is a combination of airless and air spray. Spraying is accomplished using 50-70% of the normal airless pressure required to spray the material. At this airless spray pressure, the spray pattern has power lines at the top and bottom. This is called the tail. By adding a small amount of air (25-30 psi) to the paint near the nozzle, cultivation lines are eliminated and a fully atomized spray pattern is obtained.
• More control than heavy breathing, but with a similar application rate
• Better transfer efficiency with spray nozzles than airless and conventional air spray
• Better product design than no ventilation, more like blowing
• This spray method has no obvious disadvantages.
All previously described aerosol finishing systems are available in electrostatic design.
How does electrostatics work?
The applied material is negatively charged up to 90 kVA. When the material is sprayed from the gun, it hits the soil closest to the workpiece. The stress on the paint causes most of the paint to be pulled towards the edges and back of the workpiece.
• Significantly reduces spraying
• Saving paint
• Low cab maintenance costs
• Labor saving
• Less spray capacity required.
• The product must be grounded.
• The paint must be suitable for use in an electrostatic field.
This device is available airless, airless or airless.
How does the plural work?
The base and actuator are pumped separately into manifolds or multi-component spray guns. The mixture is then mixed and immediately applied to the workpiece through a nozzle.
• Saving labor
• Saving materials
• Proper mixing guaranteed
• Allows the application of short-lived materials.
• Can be tricky to use
This allows less solvent to be used to achieve spray viscosity. Higher membrane structures or materials used. Faster drying time.
Based on https://www.spraydirect.co.uk/acatalog/about_paint_spraying.html and https://www.graco.com/gb/en/products/emea-manufacturing/technology/applicator-technology.html