Dürr’s Open House in Germany earlier this year saw all of the group’s business units presenting their innovative technologies with the motto: “Efficiency in the handling of energy and resources”
In the paintshop application area, most important new model launch in is the EcoBell3, a new generation of atomizers for the electrostatic application of water-based paints in conjunction with external charging. The performance of this atomizer surpasses its predecessor by far. Its new features not only lead to minimal losses during colour changes and shortened colour change times, they also offer new process technology options. The most important element, however, is that the EcoBell3 is equally suitable for both interior and exterior painting. This has been achieved by using a very compact electrode ring. With it, the atomizer represents an almost ideal synthesis between high performance and process flexibility on the one hand, and the greatest simplicity on the other.
In one of the first orders with this atomizer for a sports car manufacturer, both interior and exterior painting were combined in one zone – the planned capacity of the plant was suited to this. The main benefit of this was a significant reduction of plant length as well as the number of robots, and hence a reduction of the investment and operating costs. If a division of the interior and exterior painting scopes is needed for different zones – and this is certainly the norm in a paint shop – the use of EcoBell3 allows the work scopes to be distributed among all the robots in a way that optimum utilization takes place. In addition, this opens up the possibility of degrade functionality. This means that the failure of one robot in the painting scope can be covered by the remaining robot – a function that makes the so-called backup zones with manual application superfluous. This also significantly reduces plant length and operating costs.
As general engineering contractor, Dürr is building the new paint shop at the SGM Dongyue site in Yantai, a joint venture of SAIC and General Motors. The contract awarded by SGM is worth more than €60 million. Environmentally friendly painting is becoming an increasingly important issue and plants in China are leading the way in many areas. Dürr is to install their EcoDryScrubber overspray separation system, already proven in the supplier industry, in Yantai. It enables up to 60% reduction of energy consumption via a recirculation process in comparison to conventional spray booths. Overspray will be separated with a dry process on the three production lines in Yantai. The innovative technology behind this process is already working in 14 operations on four continents. Good environmental management is further ensured by the use of a water-based primer and base coat. The requirements for a future primerless process have already been established; this is a logical next step for resource-saving and effi cient production. A total of 44 type EcoRP E033 painting robots with the EcoBell 2 high speed rotation atomizer are in operation for fully automated exterior painting in the primer line and in both top-coat lines. In addition, the integrated ICC colour changer in the primer line saves time and material. Included in the specifi cation, besides seam sealing and cavity-preservation, Dürr is also installing a pendulum conveyor for pre-treatment and cataphoretic dip-coating. The Yantai paint shop is designed for an output of 60 vehicles per hour. Production should begin in mid 2012 with painting for various Buick and Chevy models.
Tight corners and compact carriers
An important application area for the EcoBell3 is the painting of bumpers and plastic components. From the application perspective, the bumper unites the demands of exterior and interior painting in one component. Large surfaces must be covered along with detail areas that partly include some very complex geometry that can only be made using plastic parts. The painting process is made more difficult by the fact that the individual parts are usually positioned closely together on the product carrier and the cycle times are very tight. This application requires a compact, powerful atomizer with a high flexibility with respect to jet shaping, and the ability to paint continuously without interruption. The EcoBell3 is designed to meet these requirements.
The EcoBell3 is only one component, albeit a very important one, of the overall "painting robot” system. This consists of the robot itself, as well as the integrated application technology. Together with a new linear colour changer, the EcoLCC, and the compact dosing pump, the robot features a very slender arm that is ideal for applications with reduced accessibility. The application technique is designed for all painting tasks and an electrical potential separation system is not needed. High transfer efficiency and minimal colour change loss are other important features of this simple and compact overall system.
Moving into the third dimension
In another area of paintshop technology, Dürr has introduced a new variant of its high performance Ecopaint RoDip dippainting process. The RoDip process optimises the process of dipping, flooding and draining by rotating the entire car body. This optimises the transport of bodies along the process line in the pre-treatment (PT), cathodic electrocoating (EC) and body washing processes.
As an improvement over the earlier RoDip M, with its drive chain on both sides of the tank, and RoDip E, with an electric drive positioned on one side, the new RoDip V offers maximum mobility in the third dimension. RoDip V has a vertical axis – which the V stands for – and thus significantly increased mobility. The vertically adjustable axis allows the car body to move particularly flexibly in freely programmable dip curves through the tank. This means that the car body can be rotated with RoDip V, but it does not have to be, thus it is adaptable to all curve shapes. Another advantage being able to use the vertical axis: the car body can be positioned over the dip tank at its own optimal draining angle. It is adjustable to all angles between 0 and 90°.
This leads to higher quality and less rework. As with RoDip E, RoDip V is furnished with an electric drive positioned on one side,and is thus easily accessible from the opposite side for maintenance. The unit has a conveying drive and a separate drive for rotation. The transport unit is positioned via a path measuring system. A wireless signal is used to communicate with the controls.
For different technical requirements, capacities, and car body styles – Ecopaint RoDip M, E and V are designed to provide the right solution for each application. Which of the three models to use depends mainly on capacity and flexibility requirements. All three technologies can be used for plant capacities of more than 100 units per hour. The RoDip variants differ economically depending on their production rates. The robust, mechanical RoDip M is more suitable for high production rates over 40 units per hour and the electric RoDip E is better for medium and smaller rates under 40 units per hour. Ecopaint RoDip V is especially suitable for special cases such as small production capacities or specific car body requirements. For truck cabs the choice between linear or rotary movement can be very helpful due to their relative difficulty in draining. In addition, RoDip V guarantees high flexibility with future model changes.