Surface World March 2019 SW_March_2019_LR | Page 34

PRE-TREATMENT, SURFACE PREPARATION, DEGREASING & CLEANING
plasma cleaning operation is integrated into
the wet chemical cleaning line. Since virtually
all components needed for this cleaning
technology – e.g., vacuum, measuring and
control equipment – are already in place in
the manufacturer’s wet chemical cleaning
machines, the additional cost and
engineering effort remains modest. The
advantages of the integrated plasma
cleaning process in ultra-fine degreasing are
substantial, on the other hand, including a
high operating flexibility, reduced process
times, low investment and operating costs,
plus very compact equipment build.
Cleaning is initially performed as usual by a solvent-based wet
process, followed by vacuum drying of all workpieces. The work
chamber is then rinsed and its internal pressure is reduced to less than
1 millibar, whereupon the process gas (e.g., filtered ambient air or
oxygen) is introduced and the plasma is ignited. Due to excitation by
the process gas, a plasma of high-energy ions and free electrons –
plus other reactive particles – is thereby formed in the vacuum.
Contaminants on the part surface, such as grease or oil residue, are
chemically attacked and transformed into volatile compounds. At the
same time, the plasma’s UV radiation likewise exercises a cleaning
effect, e.g., by breaking down long-chain hydrocarbons. The gaseous
decomposition products of the plasma treatment are extracted from
the work chamber by suction. Thanks to the combination wet-process
and plasma cleaning operation, the free surface energy that is key to
achieving an optimum adhesion strength can be raised to 50 to 80
mN/m in one single process step.
Integration of different pretreatment
methods into one system
The partial or full-surface cleaning and activation – and, in part,
coating – of individual metal or plastic products is central in the
expansion of Ecoclean’s process portfolio. For these diverse
objectives, compact application systems were developed for
integration into a host of requirement-focused equipment concepts.
Each system can be fitted with different treatment technologies such
as atmospheric pressure plasma, EcoCsteam, laser, CO2 snow
blasting or EcoCbooster processes, whether configured as an
automated standalone unit or integrated into a production line. The
company’s aim is to solve each of the various surface treatment
requirements with the most technically and economically beneficial
technology. Thus, the use of the new Disc-Jet atmospheric pressure
plasma source developed by the Fraunhofer Institute for Surface
Engineering and Thin Films (IST) permits laminar and contoured as
well as depth processing. Due to the so-called “cold” surface
discharge (30 to 60°C), even temperature-sensitive substrates can be
treated in this manner. An atmospheric pressure plasma, for instance,
allows part surfaces to be selectively fine-cleaned, activated and
coated with an adhesion promoting agent. Where the surface is to be
textured as well as cleaned, laser treatment is the method of choice,
depending on the given material. EcoCbooster technology provides a
pretreatment method for the selective, effective and efficient activation
of surfaces prior to, e.g., thermal spraying. The automation system,
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MARCH 2019
Compact application systems can be fi tted with
different treatment technologies such as
atmospheric pressure plasma, EcoCsteam, laser,
CO2 snow blasting or EcoCbooster processes,
whether confi gured as an automated standalone
unit or integrated into a production line.
too, is perfectly adapted to the specific requirements and application
situation. Thus, robot-based solutions can be realized just as readily
as multi-articulated handling systems and CNC linear drive units.
Across all variants, either the workpiece, the tool or both can be
moved to match the given task definition. Thanks to this high
flexibility, the new surface treatment toolkit is the perfect solution for
diverse applications in electromobility, medical equipment technology
and numerous other fields of industry.
Ecoclean GmbH, 70794 Filderstadt, Germany
Visit: www.ecoclean-group.net
twitter: @surfaceworldmag