Plasma activation with Venjakob

Venjakob offers plasma activation, an excellent method for surface modification that optimizes the surface to promote perfect finish adhesion. But what exactly is plasma activation? What does it do? How is it done and what do you need to keep in mind when doing it? Generally speaking, plasma activation changes the surface of a product about to be coated in a way that provides better adhesion for the coating. For instance plasma removes particles that contaminate materials about to be coated – particularly very small contaminants. In concrete terms, this requires a supply of energy, which causes a change in the aggregate states from solid to liquid and gaseous to plasma. This process creates surface tension with polar-charged molecules, to which coating materials can connect so that their adhesion is improved. The result: thorough cleaning and excellent preparation for the coating process – that’s what plasma activation does. But let’s start at the beginning.

Surface modification with ionized gas

Plasma activation with ionized gas guarantees particularly efficient surface modification, e.g. of plastics, metals or composite materials. Plasma activation modifies the surface energy precisely and selectively exactly where it is required. Oxygen plasma can also be used for cleaning – for example, to prepare the surface for adhesives that are applied in a later step. Oxygen can be combined with other gases – this is recommended, for instance, when etching surfaces. In general, the result of plasma activation is a significantly better surface wettability. This creates the ideal conditions for subsequent coating of the workpieces and materials. Among surface pretreatment processes, plasma is only one activation process along with flame treatment and flame silicification.

The different varieties of plasma activation

Plasma activation is a process that comes in a variety of forms. The different methods include the atmospheric pressure method, corona treatment and activation by low-pressure plasma.

Atmosphärendruckplasma – kurz AD-Plasma genannt

Atmosphärisches Plasma lässt sich unter Normaldruck erzeugen. Der Vorteil besteht darin, dass Sie keine Niederdruckkammer benötigen. Eine spezielle Düsentechnik bringt das potentialfreie Plasma unter Normaldruckbedingungen direkt in den Fertigungsprozess ein. Die Ergebnisse sind dabei durchaus mit Niederdruckplasma vergleichbar. Industrielle Anwendung findet das Verfahren bei der Reinigung und Aktivierung von Metallen und Kunststoffen. Die Integration des Verfahrens in bestehende Produktionslinien ist – auch durch den Verzicht einer Niederdruckkammer – hinsichtlich der Kosten relativ überschaubar. Es eignet sich insbesondere, um auf Metallen Schichten zum Schutz vor Korrosion sowie zur besseren Haftvermittlung aufzubringen. Und dies meist ohne Lösungsmittel. Somit ist das Verfahren auch umweltfreundlich. Möglich ist damit die Plasmareinigung von metallischen Endlosprofilen, von Rohren vor der Ummantelung, Lackierung oder ihrer weiteren Behandlung mit Klebestoffen. Robotertauglich ist das Verfahren obendrein.

Die Coronabehandlung mit DBD-Plasma

Die Oberflächen vieler Kunststoffe – zum Beispiel Polypropylen – sind meist wasserabweisend und elektrisch gut isoliert. Die Benetzung mit Farben, Lacken und weiteren Beschichtungsstoffen wie einem Kleber oder einem Haftvermittler ist da sehr problematisch. Was hier hilft, ist die sogenannte stille elektrische Entladung mit DBD-Plasma. DBD steht für Dielectric Barrier Discharge. Dabei erhöht die Behandlung der Materialoberflächen mit Plasma einer dielektrischen Barriereentladung deren Oberflächenenergie und somit auch die Adhäsionskräfte der Oberfläche. Diese Anhangskräfte erhöhen die Anziehung zwischen den Molekülen der behandelten Grenzflächenschichten. Einfach gesagt: mit dieser Erhöhung verbessert sich die Benetzbarkeit signifikant. Genau dank diesem Effekt wird bei der Produktion und Veredelung der Materialien die Aktivierung mittels Coronabehandlung industriell eingesetzt. Tatsächlich ist es eines der häufigsten Verfahren.

Niederdruckplasma

Niederdruckplasmen kommen bei diversen technischen Anwendungen zum Einsatz – zum Beispiel bei der Herstellung mikroelektronischer Bauelemente sowie bei der Veredelung von Oberflächen. Ein weiteres Anwendungsfeld ist die Beschichtungstechnik. Auch Venjakob nutzt dieses Verfahren der Plasmabehandlung. Bei der Erzeugung von Niederdruckplasma ist der Druck erheblich niedriger als der Erdatmosphärendruck. Sie werden im Druckbereich von nur wenigen Pascal betrieben und zählen zu den nichtthermischen Plasmen. Die Behandlung von Bauteilen erfolgt in einer speziellen Behandlungskammer, eben der Niederdruckkammer.

Areas of application

Plasma activation is used in the following fields:

Goals of plasma treatment

Ultra-fine cleaning
Increased wettability
Improved adhesion

Use

Plastic
Metal
Composites

The advantages of Venjakob plasma systems

At this point we could say that the advantages of a Venjakob plasma system are flexibility, flexibility and flexibility. First, because the modular design makes Venjakob plasma systems easy to integrate into existing plants and production lines – whether they are continuous flow systems, robot systems or spindle chain systems. Second, because it's available as a stand-alone solution, if that’s what you are looking for. And third, because every solution we offer is customized – tailored precisely to your production techniques, plant technologies and requirements. But flexibility is obviously not the only advantage: Of course, the real benefits are the top-quality this method achieves:

Ultra-fine cleaning: The finest contaminants, the finest deposits, barely visible or even completely invisible dirt don't stand a chance – simply activate with plasma and the surface is cleaned – thoroughly! To put it simply: Plasma can be used for ultra-fine cleaning in a variety of ways. Another method is the use of plasma-vacuum technologies, that is, the low-pressure method, which has the advantage of cleaning much larger surfaces.
Increased wettability: Plasma treatment ensures that material and molecules are open for optimal wetting. All treated materials are ready for a coat or finish.
Optimized adhesion: Plasma treatment significantly improves the adhesion of coatings. The reason for this is that the plasma modifies the surface during treatment. The surface of the object treated with plasma becomes smooth due to the increase in surface energy. This, in turn, improves the adhesion properties of the coating.

Stand-alone or part of a line – but always completely customized.

We have mentioned it before, but perhaps some more detail would be helpful: Your Venjakob plasma system is also available as a stand-alone solution. Or Venjakob can offer you a complete start-to-finish solution incorporating feeding, the necessary pretreatment, which includes plasma activation, followed by the actual coating system itself, as well as drying systems and exhaust air purification. All components are perfectly coordinated – from loading to discharge. Venjakob can offer you a complete start-to-finish solution incorporating feeding, the necessary pretreatment, which includes plasma activation, followed by the actual coating system itself, as well as drying systems and exhaust air purification. All components are perfectly coordinated – from loading to the continuous chain conveyor system or throughfeed system to discharge. The design process always includes all possible aspects of process optimization, whether it's parameter control or throughput speed, self-cleaning steel belts or easy cleaning of the spray booth.

Let's talk – about plasma activation and your Venjakob system

To explain briefly, plasma activation is a technology that optimizes and cleans surfaces. It is also frequently referred to as plasma treatment or plasma cleaning. Mostly it is used in the treatment of various materials such as plastics, metals or organic substances. In simple terms, plasma activation involves an ionized gas, the plasma, that generates a strong electric field to affect the surface of the material being treated. Plasma activation increases the surface energy of the material, making it easier for various chemical compounds to dock to the surface. Three methods can be used to do so – treatment with atmospheric pressure plasma (also called AP plasma), with DBD plasma (referred to as corona treatment), and finally the low-pressure plasma method, in which the plasma is generated in a specially designed low-pressure chamber. Plasma activation is integrated into the surface pretreatment phase, which is followed by the actual coating process – for instance spray coating. At Venjakob we are happy to offer you plasma activation as a stand-alone solution, should you request and require it. But in general we always recommend a complete solution including feeding, pretreatment, coating, drying, exhaust air purification and removal. All our custom-developed solutions are tailored to the quantities being produced, the optimum use of coating materials and, of course, the use of energy. Another advantage is process optimization, which simplifies operation and subsequent cleaning for you and your technical personnel and allows you to perform the occasional maintenance task. Should it be required, we will support you not only before implementing your order, but also afterwards.

There’s one thing that is even more important than plasma activation. Trust.

We have told you quite a bit about plasma activation. What we didn’t give you, because we wanted to spare you the dull details, are the technical specifications about wetting optimization and the physical formulas that describe in general terms what, in a specific application, always results in customized solutions. It’s much more important for you to know this: At Venjakob we have been developing and implementing coating systems for six decades. There’s an easy answer to the question of how many of them feature plasma activation: a great many. We have tested the process thoroughly – and continue to test it on an ongoing basis in our technical center. What we mean to say is: Your trust in us is more important than any formula. We would like to invite you to visit us in Rheda-Wiedenbrück to see our quality for yourself. Get in touch with us. We won't just find any solution – we will find yours.

Your contact

Our in-house technical center makes it possible to test processes under realistic conditions. Simply tell us what you need, get your material supplier involved, and we will develop a solution together with you.