Nathan Kruppe

Space-resolved plasma diagnostics in a hybrid (Cr,Al)N process

The concurrent usage of direct current magnetron sputtering (dcMS) and high power pulsed magnetron sputtering (HPPMS), the so-called dcMS/HPPMS hybrid technology, enables the combination of the advantages of both technologies. These are well known to be a higher deposition rate, compared to HPPMS processes, as well as an improved roughness, microstructure, and mechanical properties, compared to dcMS processes. However, there have not been investigations which thematically focus on the understanding of the influence of different dcMS/HPPMS plasma zones on the deposition rate and the coating properties. Hence, in the present work, a dcMS/HPPMS hybrid (Cr,Al)N process was analyzed regarding the plasma and coating properties. The measurements were carried out in an industrial scale physical vapor deposition coating unit. The plasma was analyzed space-resolved and substrate oriented to map the entire area in front and beside of the cathodes. The mean ion energy decreased from the area in front and beside of th...

Replication of micro-structured injection molds using physical vapor deposition coating and dynamic laser mold tempering

Abstract Plastics parts with micro-structured surfaces enable the development of innovative products such as optical components in sensors or light management systems for laser and LED applications. Moreover, micro-structured parts can be utilized in the medical and packaging industry for hydrophobic or antibacterial products. The production of micro-structured parts causes challenges in molding and demolding. Rough surfaces of the laser-structured mold inserts offer flow resistance during injection phase as well as increased demolding forces which cause failures of the replicated structures during ejection. Therefore, an innovative approach combines coated mold inserts by means of physical vapor deposition (PVD) and a highly dynamic laser tempering system to improve the replication of micro-structured plastics parts. Both uncoated and coated micro-structured mold inserts were used in a series of molding experiments by means of conventional and dynamic mold tempering. Based on the results, it can be shown that significant improvements of the replication of micro-structures of different sizes can be achieved by use of PVD mold coatings. This is attributed to the tribological interactions between coating and plastics melt. Furthermore, results indicate an influence of the thermal conductivity of PVD coatings to enhance replication quality.

Forward impact extrusion of surface textured steel blanks using coated tooling

A method to enable dry metal forming by the means of a self-lubricating coating and surface textures was researched using an innovative Pin-On-Cylinder-Tribometer. The experimental analysis was complemented by a numerical model of the complex contact conditions between coated tools and the surface textured specimen at the micro-level. Based on the results, the explanation of the tribological interactions between surface textured specimens and the tool in dry full forward extrusion is the objective of this work. Therefore, experimental dry extrusion tests were performed using a tool system. The extruded specimens were evaluated regarding their geometry as well as by the required punch force. Thereby, the effectiveness and the feasibility of dry metal forming on the example of full forward extrusion was evaluated. Thus, one more step towards the technical realization of dry metal forming of low alloy steels under industrial conditions was realized.

Multi-technology products

Development of technical solutions that lead to widening the use of multi-technological products as well as in assessing ecological and economic potentials of multi-technological products have not yet been studied intensively. The activities conducted in the context of this research area focus on these aspects. The aforementioned aspects have been examined, evaluated and quantified on the basis of three example products resulting from the first funding period. The research activities conducted on the example components deliver the basis for the layout of different integrated multi-technology production systems. Technical solutions that enable coupling of different process steps with each other as well as the integration of different functionalities and different materials in final multi-technology products have been proposed. The complex interdependencies of the products themselves and their associated production processes have been researched and evaluated intensively. Finally, a profitability assessment of the proposed solutions was conducted and future research topics identified.