Plasma Instead of Chemistry
Cost pressure and increasing quality demands require new process technologies in industrial production. This is where plasma pre-treatment can help. It offers the unique possibility of replacing a multitude of chemical treatment steps with a single efficient and environmentally friendly and thus more cost-effective process.
Cleaning and activation of surfaces by plasma pretreatment
Typical requirements for plasma treatments are the homogeneity and the strength of the treatment. In many material-plasma combinations, the classical contact or contact angle investigation provides only insufficient, rough macroscopic information on the activation/cleaning of the surface due to their structural or topographical dependence.
For the quantitative evaluation of plasma treatments, a scanning force microscope-based imaging method for the analysis of plasma-treated surfaces was developed in cooperation with various plasma manufacturers.
The critical parameters of a plasma-treated surface to be examined are:
- Topographic change of the surface by plasma input
- Quantization of surface hydrophilicity on the µ and nm scale.
- Change of the elastic property of the surface
- Detection and classification of imperfections
- Duration of surface activation, time constants
The combination of chemical force microscopy with the digital pulsed force mode makes it possible to determine these parameters. With a resolution in the nm range, the surface is scanned force-specifically with a hydrophobically modified measuring probe. The data obtained include information on topography, elastic properties, adhesive interaction and thus on the intensity of plasma treatment (hydrophobicity/hydrophilicity). This innovative imaging method can be used from the µm scale up to the highest spatial resolution in the molecular range. The FD technology optimised by us is used for macroscale tasks.
Plasma revolutionizes pre-cleaning in coil coating
The new 49 meter long coil coating line at Griesser AG, Switzerland, sets a milestone in plant engineering.
Griesser AG, Switzerland, one of Europe’s largest sun protection system manufacturers, commissioned the world’s first plasma pretreatment system in the coil coating process. The project was initiated and managed by Branko Vasiljevic, project manager for coil coating. The developed open-air installation replaces an approx. 21 meter long cleaning line, i.e. countless tons of chemical and process waste water are now avoided. This results in enormous cost savings and maximum environmental protection.
Corrosive attack of surfaces, remains of rolling oils and the environmentally harmful and energy-intensive wet-chemical pretreatment processes still used today represent the most frequent problems in the processing of aluminium. For this purpose, a method was developed for the first time that allowed the above mentioned problems to be completely eliminated. This technology ensures microfine cleaning of aluminium strip before application of the conversion layer. It also completely replaces the environmentally harmful wet-chemical processes in the cleaning process.
The only 2 meter wide open-air plasma plant replaces a 21 meter long cleaning line and thus tons of chemicals and waste water. Conventional chemical pretreatment was used as a reference system in the development tests. Considering the material-plasma parameters to be optimized (plasma focus, intensity/energy input), a clear superiority over conventional pretreatment methods could be demonstrated. The results obtained prove on the one hand the applicability and high effectiveness of atmospheric-pressure plasma. At the same time, open-air plasma pretreatment achieves significantly better results than the chemical reference in all areas.
The speed of the entire coil coating system has quadrupled compared to the old system due to the use of the open-air plasma process.
Translated with www.DeepL.com/Translator