A new automated system by Dürr underlines a two-tone painting capability that does away with the unwieldy and laborious masking tape process

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The EcoPaintJet applicator does not generate any overspray, removing the need to mask areas of the vehicle body

’The more customised, the better’ is a motto that governs more and more purchasing decisions. When it comes to the colour of cars, the trend toward customisation is also on the rise. Buyers of small cars, in particular, are increasingly ordering contrasting and accent colours. For example, some consumers want to change the colour of their car roof to stand out from the crowd. 

For the automotive industry, two-tone painting means considerably more cost and effort. Not only does it require more time and energy, it also creates a lot of wastage. Thanks to a pioneering innovation offered by Dürr, this is changing. 

With its EcoPaintJet system, Dürr presents an automated application solution that ensures an unprecedented level of precision in applying sharp paint lines. The EcoPaintJet also offers important benefits in the painting of electric cars. Dürr launched the solution to the public for the first time at an open house event at the company’s headquarters in Bietigheim-Bissingen, Germany.

“EcoPaintJet only takes a cycle time of 120 seconds to apply a contrasting colour to a car body roof. By comparison: to put on and remove masking tape alone is about 50 minutes.” 

Dr. Jochen Weyrauch, CEO of Dürr Systems, says: “The EcoPaintJet is a quantum leap in the journey towards the efficient, two-tone painting of cars. It is the first system to efficiently combine customised product design with automated production.”

When only one type of paint is applied, the efficiency of modern automotive paintshops is unrivalled. Thanks to their highly automated processes, large plants paint 300,000 car bodies per year while maintaining a consistently high level of quality. However, adding a contrasting or accent colour, for example on the roof or as a design strip, means a considerable amount of extra work. 

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Around 50 hardly visible holes on the EcoPaintJet nozzle plate are used to apply paint to the car body surface in parallel jets from 30mm

Once the entire car body has been painted in the basic colour, which has then dried and cooled, masking tape must be applied by hand – except for the areas due to be painted in a different colour. Then, the car body returns to the painting line, where the second colour is applied. After more cooling and drying, the tape must be removed, once again by hand. This not only results in high labour costs, but the energy consumption for the curing of paint increases by at least 25% compared to single-colour painting. In addition, 6-15 sq.m of masking tape mustbe disposed of per car body. Moreover, the painting line is blocked by the second paint application, taking up valuable time. 

A sleeker profile for EVs

EcoPaintJet helps electric car manufacturers to fulfil an important customer requirement; EVs often sit slightly higher than conventional models, with the battery pack installed into the floor assembly, under the passenger compartment. Many buyers, however, would like their cars to look low-slung and sporty. To get this effect, a dark contrasting colour is used to paint a strip between the roof and side wall as well as on the rocker panel, which gives the car a flatter, sleeker appearance. The EcoPaintJet is perfectly suited to this purpose, applying the strip precisely without compromising the existing finish.

No masking tape required

EcoPaintJet removes the need for masking the car body, thanks to a totally new applicator. Fixed to a robot arm, it moves over the target area and applies paint with razor sharp lines. The paint lands exactly on the intended areas and nowhere else – not even the tiniest amounts. As a result, the rest of the car body no longer has to be masked. It only takes a cycle time of 120 seconds to apply a contrasting colour to a car body roof. By comparison: when using masking tape, the time required to put on and remove the masking tape alone is about 50 minutes. 

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EcoPaintJet is the first system to efficiently combine customised product design with automated production in two-tone painting

No more overspray

The EcoPaintJet achieves its high level of precision because the applicator does not generate any overspray at all. Overspray refers to fine droplets of paint, which are produced by other atomisers, and land outside the target area. The EcoPaintJet has an intricately machined nozzle plate, measuring only a few square centimetres, which prevents the formation of overspray. The nozzle plate, which forms the underside of the rectangular applicator, has around 50 hardly visible holes with a diameter of approximately one tenth of a millimetre. They are used to apply paint to the car body surface in parallel jets from a distance of 30 millimetres.

The applicator is the centrepiece of the perfectly designed EcoPaintJet system. This also includes the EcoRPL 133i painting robot, which moves the applicator without any vibration. A measuring system, equipped with sensors, provides maximum precision, taking a 3D measurement of the area to be painted and sending the data to the control software. This continuously calculates along which path the applicator must be moved over the surface to achieve an optimum paint finish – this is called automatic path generation. It also determines how the applicator must turn, plus the speed required to apply exactly the right amount of paint. 

According to Dr Lars Friedrich, responsible for application technology on the Dürr Systems’ board of management: “This high-tech process enables the automotive industry to fulfil customers’ specific requirements faster while ensuring top quality. There is great interest in the market, as we are offering real added value with this new technology.”

The EcoPaintJet is currently being tested at several carmakers’ sites. In the meantime, Dürr is already working on a further development of the technology, which can also paint more complex geometries. This enhanced version, known as EcoPaintJet Pro, enables each hole in the nozzle plate to be opened and closed individually. This offers even more possibilities for product customisation. In the future, the automatic application of lettering and logos should also be possible – similar to a digital printer.