The UltraPLAS® coating, developed by Fraunhofer researchers, sets new standards in injection moulding and die casting. This ultra-thin, hard and durable coating enables the production of mirror-finish surfaces and optimises production processes.
One challenge in the injection moulding of technical plastic parts is the reduction of demoulding forces and the formation of deposits. This is particularly relevant in the production of components with high-gloss surfaces or highly defined microstructures, such as plastic lenses, decorative trims or dimensionally accurate plugs.
In zinc die casting, deposits as well as release agents and lubricants also prevent the production of high-quality, shiny metal surfaces. This leads to considerable costs for post-processing.
Research to improve mould surfaces
Researchers at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM have investigated how the process of coating high-quality mould surfaces can be improved. The aim of the ‘GlossyCast’ and ‘UltraTrenn’ projects funded by the Industrielle Gemeinschaftsforschung IGF was to reduce the demoulding forces and the formation of deposits on the mould surfaces while permanently withstanding the specific stresses of zinc die casting and plastic injection moulding.
UltraPLAS® is applied as a gradient layer to tool steel, stainless steel and aluminium using a cold plasma process. The process is characterised by outstanding physical properties and offers excellent reproduction of surfaces ranging from nanoscale to high-gloss. In addition, the elimination of external release agents and the reduction in post-processing steps leads to cost savings.
UltraPLAS® high-performance coating
UltraPLAS® was developed on the basis of the PLASLON® non-stick coating, which is characterised by high hardness (Mohs hardness 4.5 - 5.5) and temperature resistance up to 230°C.
The UltraPLAS® coating is characterised by a smooth and structureless surface, which is applied using the PE-CVD process (plasma enhanced chemical vapour deposition). The coating offers excellent coating properties, including a high modulus of elasticity (28-32 GPa) and a high density (1.5 g/cm³). With a Mohs hardness of 5.5 and a low surface energy (< 28 mN/m), UltraPLAS® ensures optimum non-stick properties.
The researchers have also succeeded in realising the UltraPLAS® coating with a particularly thin layer thickness of less than 100 nm.
Practical tests have shown that UltraPLAS® reduces demoulding forces and the formation of deposits during injection moulding. As a result, demoulding temperatures can be increased and the amount of friction reduced. Another advantage is the simple and gentle removal of the coating, which enables multiple recoating without loss of quality.
Improved efficiency in zinc die casting
The UltraPLAS® coating enables the direct production of high-quality zinc die-cast surfaces and reduces the need for time-consuming and cost-intensive post-processing steps. This leads to improved economic efficiency and environmental friendliness of the production processes. The smoother surfaces significantly reduce material consumption and pre-treatment time for galvanisation.
