Processing plastics efficiently
Tried and tested solutions get a new home: As one of the leading providers of surface solutions, Oerlikon Balzers presents its extended coating portfolio with unique solutions for plastic processing, following the integration of the former Sulzer Metaplas GmbH.
Extremely thin PVD coatings are not only able to extend the lifetime of tools, prevent tool damage and reduce maintenance costs, but can also reduce deposits and the use of release agents. Furthermore, they improve the gliding behaviour of moulding materials on the inert tool surfaces. All of these advantages are provided by the two tried and tested, modified CrN-based coatings, which were included in Balzers’ coating portfolio under the following names: BALINIT CROMA and BALINIT CROMA PLUS.
Typical usages of both coating solutions are in the areas of extrusion, particularly foil extrusion, and rubber processing. CROMA and CROMA PLUS also have many possible usages in injection moulding applications for various plastics.
Reducing abrasive wear and adhesive bonding
As a result of the multi-layer structure of the BALINIT CROMA coating, the individual coating layers are sealed via metallic intermediate layers so that corrosive fission products can no longer diffuse through the coating and cause subsurface corrosion. Corrosion, which can occur when processing plastics due to residual moisture in the granules, for example, is also contained.
The special coating structure also gives rise to other advantages such as the possibility of greater coating thicknesses and an adjustable micro-roughness. An additional high oxidation resistance and excellent coating adhesion also ensure that this surface solution is ideally suited wherever there are problems with corrosion, abrasive wear and adhesive bonding. This coating is particularly suitable for plastics such as PA or ABS, for example.
Thus no wear is evident in practice for BALINT CROMA-coated extruder screws even several years after the coating. It was possible to vastly improve the lifetime and save production capacities through reduced wear checks.
Increasing the lifetime by 5 times
BALINIT CROMA PLUS coatings are particularly striking because of their characteristic rainbow colour. This is due to the virtually amorphous, doped top coating. It provides a strong anti-adhesive property with respect to highly adhesive moulding materials such as rubber compounds and thermoplastic elastomers. In conjunction with the high level of coating hardness, abrasive wear is significantly reduced by hard fillers and deposit formation is avoided.
The specific advantages are particularly evident when processing plastics such as PMMA, POM, PUR and NBR, for example. Customers report an improved surface finish of the components after using BALINIT CROMA PLUS for calibration bars. Deposit formation can be reduced during the coating of
spiral mandrel dies for foil production, resulting in reduced cleaning cycles for these spiral mandrel dies during production. Thus maintenance intervals, which had to take place annually in the absence of BALINIT CROMA PLUS, could be increased to a 3-year cycle. Enormous improvements are also evident in the material output; customers report an increase of 5%.
Also protecting large and long components against wear
The modern coatings are also available for particularly large and long components. Tools such as screws or sheet dies can be easily coated with a length of up to 4,500 millimetres, or spiral mandrel dies with a diameter of 1,400 mm, which are used, for example, for granule processing, foil production or other areas of plastic processing.