New Dürr atomizer generation for the sustainable the paint shop

Paint losses and rinsing agent consumption can be reduced by 50 % during color changes, or even by up to 91 % in combination with the EcoProBooth modular paint booth concept. The improvements are made possible by the unique 4-main needle technology as well as changes to the process parameters for paint application.

The higher the efficiency during paint application, the less material, resources, and energy are required. In other words, higher efficiency makes for more sustainable production. With the latest atomizer generation EcoBell4 Pro Hu with direct charging and EcoBell4 Pro Ux with external charging, Dürr is scaling new heights. For clear coat application, application efficiencies of 95 to 98 % are achieved according to DIN EN 13966-1.

For the atomizer to apply the paint with maximum efficiency, the process parameters are set as follows: The speed and spray distance are significantly reduced. This maximizes the effect of the high voltage. The flow rate of the paint remains high. In addition, the shaping air is reduced to a minimum and the high-voltage control is adjusted. Dürr is testing the implementation of this painting process in a concrete automotive paint shop in a collaboration with interested OEMs. Existing systems can be retrofitted too.

How the measures impact the paint process

Reducing the shaping air volume to a rate of between 90 and 200 standard liters per minute produces a softer spray jet. Together with a lower bell disk speed, energy consumption is reduced. If the spray distance is decreased to around 100 millimeters at the same time, more paint reaches the car body. There are two reasons for this: Firstly because the spray pattern is much less scattered, and secondly because a stronger electrical field between the bell disk and car body surface enables optimum use of the electrostatic force via a constant voltage.

The atomized paint therefore reaches the body to a far greater extent instead of being lost in the booth air. In order to achieve the required layer thicknesses in the given cycle time, a paint outflow rate of up to 400 milliliters per minute is possible. In total, the EcoBell4 Pro Hu with direct charging achieves efficiencies of up to 98 % for clear coat in this way.

With the EcoBell4 Pro E atomizers with external charging for exterior painting, the efficiency for base coat also increases from 75 to 78 % compared with the predecessor model EcoBell3. The EcoBell4 Pro Ci atomizer for interior painting also continues to achieve unrivaled high efficiencies of up to 70 %. Efficient collaboration with OEMs and paint suppliers in the Dürr technical center offers further potential for improving the efficiency and the quality of paint application.

Fast colour changes reduce paint and rinsing agent consumption

In addition to the painting process, technical innovations in the design elevate the EcoBell4 atomizer generation to a new quality level. The new generation makes the painting process more flexible and more efficient, and therefore more sustainable. Colour changes can be carried out more quickly with the EcoBell4 than with any other high-speed rotary atomizer on the market. This is because the patented 4-main needle technology not only saves time, but also reduces paint and rinsing agent consumption as well as VOC emissions.

Three of the four main needles are reserved exclusively for the most frequently used colours. All other colours go through the fourth main needle. Real-world evidence shows that in the automotive sector, 50 percent and more of the total number of bodies are painted in the three most frequently used colours.

The technology leverages this fact and provides the three colours permanently via the main needles. These are located directly behind the bell disk. When a colour change is due, the system can switch to another main needle within four seconds without it being necessary to rinse and clean the channel. This reduces both the paint losses and the rinsing agent consumption associated with colour changes. If a less frequently used colour is requested, the colour can already be primed via the fourth channel while one of the three main colours are still being applied. This means that each colour is available for the next body within an extremely short time.

Further savings in the paint shop

Compared with the predecessor model EcoBell3 (1C), the consumption of paint and rinsing agent is reduced by 51 percent in the conventional line setup. This is good for the environment and minimizes the process costs. The new atomizer generation is especially efficient and sustainable in combination with the EcoProBooth. Since the interior and exterior painting can be performed in a single booth, not only the color change times but also the handling times are reduced compared with the line concept.

The universal atomizer EcoBell4 Pro Ux is a perfect match for the EcoProBooth. It is suitable for interior, exterior, and metallic painting, and uses one and the same bell disk/shaping air ring system and external charging system for this.

The combination of the EcoBell4 Pro Ux and EcoProBooth even permits savings of up to 91 percent during color changes by reducing paint losses and rinsing agent consumption. “This is a huge step. Our model calculations are based on a paint shop that uses 24 colors and coats 30 bodies an hour, working 230 days a year on a three-shift basis. The amount of paint saved would be enough to paint an additional 15,600 bodies,” says Frank Herre, Head of Application Technology Development at Dürr.

Just four robots reduce colour change and handling times

The system with up to four main needles covers all painting requirements, from the 4x1C solution for base coats to the 3x2C solution for clear coats. Dürr offers a total of ten different versions of the EcoBell4, for all exterior and interior painting applications with direct or external charging. For the first time, the product family includes a basic version for standard applications as well as a pro version for special processes such as 4x1C or 3x2C.