APS reports on a new chemical-free process that uses saturated steam and high-velocity air to remove contamination reliably, quickly and cost-effectively
Improved sustainability, increased cost-effectiveness and constant quality optimisation are some of the most important aims of the automotive industry. An innovative cleaning technology that is used, among other things, to clean components before coating, aims to support these goals. The efforts made to minimize CO2 emissions, reduce the consumption of resources as well as integrate cost- and quality-optimized processes in manufacturing are leading to new developments in all branches of the automotive industry. This also affects component and surface cleaning methods.
With its environmentally-friendly EcoCSteam technology, Dürr Ecoclean has developed an innovative steam-cleaning process, which rapidly and reliably removes a multitude of contamination such as oil, grease, emulsions, separating agents, chips, dust and fingerprints from any material without the need for chemicals. The new technology has also proved to be highly effective for a number of tasks, such as cleaning components and surfaces before they are painted.
Compared to other cleaning techniques, the system gives better cleaning results and enables much shorter cycle times. At the same time, investment and operating costs are significantly lower and the footprint is smaller. The EcoCSteam system can be installed in a painting booth and easily automated with the use of robots.
New steam generating techniques
In collaboration with vapor experts, Dürr Ecoclean developed a solution to generate steam based on the principle of continuous flow hot water systems: pressurized water flows through a pipe system fitted with heating coils which, depending on the cleaning task required, heat it to temperatures ranging between 135°C and 280°C. The water is converted to steam before being pumped out of the pipe and fed to the cleaning nozzle. Compared to standard boiler systems, this innovative method of continuous-flow steam generation enables the volume and quality of steam to be kept constant, thus assuring reproducible cleaning results.
The EcoCSteam PLC control system accurately adapts the flow of water and steam as well as thermal output to the cleaning task at hand, continuously monitoring parameters and adjusting them as required.
Effective cleaning with steam and air
This highly efficient cleaning method is based on the combination of saturated steam and a high-velocity flow of air. As the steam jet exits the nozzle, a jacket of high-speed hot air first bundles and concentrates the jet and then directs it at the surface to be cleaned. Due to the high velocity of the airflow and the properties of the steam, the two media remain separate from one another.
The amount of liquid contained in the steam is adjusted as required to the cleaning task or form of contamination present. Thus, for example, wet steam is used to remove oil because it alters the viscosity of the oil to the extent that it causes it to atomize as tiny droplets. The droplets are then blasted off the component surface by the airflow, together with any particulate contamination present. The high-velocity airflow then dries the surface.
As the cleaning process is carried out in just one or two steps, cycle times are much shorter than with previous systems, thus helping to increase productivity. The EcoCSteam technology also scores from the economical point of view because investment costs are much lower. Operating costs are less, too, firstly because the technology dispenses with the need for chemicals or baths with filtration systems, and secondly due to the low maintenance requirements and high availability.
Already proven in series production operation
The EcoCSteam technology has been running in series production in the automotive industry since the end of 2010. The first system is installed at a well-known American motorcycle manufacturing company and is used to clean metal tanks and fenders before they are painted.
Beside the excellent cleaning and drying results attained, another reason behind the decision to purchase the technology was the fact that no chemical-based cleaning agents are required. The process is carried out automatically by a robot fitted with two steam-air nozzles. Specific programs are filed in the system controls to enable flexible, component-adapted cleaning. After being removed, contamination is guided by a laminar airflow in the booth to a filter unit. The company has meanwhile placed an order for a second line.
The EcoCSteam technology has also established itself in the plastics industry and is currently in operation, for example, at a French automotive supplier. The company has already been using the technology to clean plastic parts before painting processes for about six months. In two booths equipped with robot systems, dust, grinding waste and fingerprints are removed from the composite components before they are coated. Combined with the very short cycle times, this has enabled throughput to be doubled. The convincing results and high cost efficiency have motivated the supplier to place a further order with Dürr Ecoclean.