Interior and exterior painting combined in one spray booth
The variety of models in the automotive industry is growing, and with it the broad spectrum in which individual plants have to produce. This requires greater flexibility in production in order to meet the constantly increasing requirements of the future. Dürr has therefore developed the concept of the “paint shop of the future”, which is based on a visionary layout with flexible boxes instead of the conventional rigid line. The innovative EcoProBooth painting booth is optimally matched to the box layout and combines up to three painting processes – interior and exterior work – in just one booth. Up to eight painting robots, supported by four Scara robots to open the doors, apply the paint to the body – both inside and outside. This saves process time: Firstly, two of the three previously used conveyor processes are no longer required, since the bodies remain in the cabin and do not have to be moved from one cabin to the next between the application processes. Second, the robots for the exterior painting can be cleaned when they pause while the rest of the robots apply the interior painting – and vice versa. By distributing the tasks, different, optimally coordinated application techniques can be used for the exterior and interior painting in a booth in order to achieve the best possible quality.
The new paint booth has so-called service booths: service booths that are integrated into every corner of the paint booth, are continuously flushed with fresh air and are accessible at any time without hesitation. When a robot needs cleaning or maintenance, it moves to the service booth and extends its arm through a connecting window into the service area, where an employee can easily reach it. The limit values for a workplace without health risks are adhered to. Previously, production had to be stopped at least every two to four hours in order to clean robots or carry out minor maintenance work. Now atomizers can be cleaned or bell plates can be replaced during production without the employee in charge having to enter the application area in the spray booth. This increases the system availability considerably.
Low energy consumption through maximum air circulation
With regard to the air circulation rate, the spray booth goes to the maximum in order to minimize energy consumption and thus CO2 emissions. While the ratio of circulating air to fresh air in a classic dry separation system is 80:20, the ratio for EcoProBooth is 95: 5. The spray booth is equipped with a dry separation system (EcoDryScrubber) as standard, which guarantees 100% paint separation regardless of the paint materials or paint mixtures . Here the air is first cleaned of paint particles and then overhauled in a circulating air system that is directly assigned to the spray booth. The energy required to prepare the circulating air is much less than to prepare the fresh air from outside, which generally differs more widely from the conditions in the cabin depending on the region and season. The maximum air circulation rate thus keeps the energy consumption and CO2 emissions for conditioning as low as possible. Compared to previous painting booths that were operated with circulating air, the increased amount of circulating air saves 10 to 15% energy and thus also CO2.
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Maximum flexibility with low material consumption
The paint booth shows its full strength in the modular box concept. It enables easy scaling according to changing quantities. Assuming a body mix of small cars and medium-sized SUVs, the cab is designed for 12 jobs per hour. A higher capacity can be achieved with smaller vehicles or less painting effort. In order to adapt the system to a higher demand for higher quantities, several boxes are arranged in parallel and side by side. In contrast to a line layout, with a parallel arrangement, a malfunction only affects the affected stand. Production in the remaining booths can continue, which increases the availability of the entire line. The size and layout of the box are standardized so that simple conversions and extensions are possible without affecting production in other box sections. The box layout also reduces material consumption due to lower losses when changing colors. By dividing the line into shorter sections, coating jobs can be distributed in such a way that color changes are minimized. This saves coating and rinsing agent and thus reduces both costs and VOC emissions.
The full article was published in the September issue of JOT in German.
Author (s): Dürr