Effects of mould wear on hydrophobic polymer surfaces replicated using plasma-treated and laser-textured stainless steel inserts

ABSTRACT

The mass production of polymeric parts with functional surfaces requires economically viable manufacturing routes. Injection moulding is a very attractive option, however, wear and surface damage can be detrimental to the lifespan of replication masters. In this research, austenitic stainless steel inserts were hardened by low temperature plasma carburising and then different micro and nano scale surface textures, inspired by Lotus leaves and Springtail skins, were laser fabricated. A commonly available talc-loaded polypropylene was used to produce 5000 replicas and thus to investigate the evolution of surface textures both on inserts and replicas together with their functional response. The progressive wear or surface damage on the inserts during the injection moulding process had a clear impact on surface roughness and peak-to-peak topographies of the replicas. In general, polymer replicas produced with the carburised inserts retained wetting properties for longer periods compared with those produced with the untreated replication masters.

KEYWORDS:

• Wear
• injection moulding
• plasma surface alloying
• laser texturing
• wettability

Acknowledgements

The research was carried out in the framework of two EU H2020 Marie Skłodowska-Curie actions: ‘Short Pulsed Laser Micro/Nanostructuring of Surfaces for Improved Functional Applications’ (Laser4Fun, grant agreement No. 675063, www.laser4fun.eu) and ‘High-Impact Injection Moulding Platform for mass-production of 3D and/or large micro-structured surfaces with Antimicrobial, Self-cleaning, Anti-scratch, Anti-squeak and Aesthetic functionalities’ (HIMALAIA, No. 766871). The work was also supported by twor EU H2020 Factories of the Future initiatives: ‘High-Impact Injection Moulding Platform for mass-production of 3D and/or large micro-structured surfaces with Antimicrobial, Self-cleaning, Anti-scratch, Anti-squeak and Aesthetic functionalities’ (HIMALAIA, No. 766871) and ‘Modular laser based additive manufacturing platform for large scale industrial applications’ (MAESTRO, No. 723826). Further support was provided by the UKIERI DST programme ‘Surface functionalisation for food, packaging, and healthcare applications’. Finally, the authors would like to acknowledge the support and assistance of the University of Bradford and BSH Electrodomésticos España, S.A. in conducting this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The research was carried out in the framework of the Laser4Fun project on ‘Short Pulsed Laser Micro/Nanostructuring of Surfaces for Improved Functional Applications’ (Laser4Fun), which has received funding from the European Union’s H2020 research and innovation programme under the Marie Skłodowska-Curie Actions (MSCA) Innovative Training Network (ITN-ETN), grant agreement No. 675063 (www.laser4fun.eu). The work was also supported by three other H2020 projects, i.e. ‘High-Impact Injection Moulding Platform for mass-production of 3D and/or large micro-structured surfaces with Antimicrobial, Self-cleaning, Anti-scratch, Anti-squeak and Aesthetic functionalities’ (HIMALAIA, H2020 Factories of the Future (FoF) initiative No. 766871), ‘Process Fingerprint for Zero-defect Net-shape Micromanufacturing’ (MICROMAN, H2020 MSCA ITN-ETN No. 674801) and ‘Modular laser based additive manufacturing platform for large scale industrial applications’ (MAESTRO, H2020 FoF No. 723826). Further support was provided by the UKIERI DST programme ‘Surface functionalisation for food, packaging, and healthcare applications’.