Schmitz Cargobull AG
Photo: Schmitz Cargobull
Use of Openair®-Plasma application for structural bonding of reefer semitrailer superstructures
Since 2003 Schmitz Cargobull AG, Europe's leading trailer manufacturer pretreats annually more than 15000 reefer semi-trailers with Openair® plasma before their structural bonding. The previously manually performed tasks of surface cleaning and roughening were to be replaced by an industrial process. The primary objective was to completely eliminate organic solvents and thereby to exclude the potential risk of environmental pollution.
The refrigerated semi-trailers’ superstructures feature a self-supporting system, a modular structure which is built completely rivet-free. Walls and ceilings of the semi-trailers consist of a sandwich construction. This is a vapor diffusion-tight panel with two plastic-coated steel plate surface layers and an interposed high-density polyurethane hard foam core. The self-carrying characteristic is created by adhesive bonding of the large-size panel into angled aluminium rails. For achieving extremely good adhesion and particularly tight sealing of the bonding joints, the panels are pretreated with Openair® atmospheric pressure plasma in the area of the surfaces to be bonded. The coatings are mainly duroplasts which are given new adhesive-friendly surface properties by plasma activation.
Technical uncharted territories require learning processes on the part of the users as well as supporting accompaniment of the developers. Johannes Pierick, Director Quality Control and Application Technology at Schmitz Cargobull, recalls: “Plasmatreat had promised us qualified technological support in case of a contract of purchase. This commitment – decisive for the conclusion of the contract - was implemented by the staff members of Plasmatreat to our greatest satisfaction from the first day of cooperation until today. After the long-term use of Openair®-Plasma I can state today: The results are excellent!”
The plasma installation consists of two nozzle systems with four rotary nozzles which are offset to each other. The nozzles distribute the plasma at a 45° angle, with a treatment width of 47mm per nozzle. Depending on the direction, 150-180mm of the surface can now be cleaned and activated in a single pass on a minimum width of 300 mm and over the entire length or width of the panel.
Openair® plasma offers the user the following benefits:
- Environmentally friendly manufacturing method
- Complete elimination of organic solvents in the bonding process
- Space-saving application of the plasma installation
- High process safety
- Improved adhesion and tightness of the bonding joints
- Elimination of work steps > Rationalization of the manufacturing process
- Exclusion of environmental impact at the workplace
- Operating cost reduction
Schmitz Cargobull AG