Thomas Frederik Linke

Influence of Process Parameter on Grit Blasting as a Pretreatment Process for Thermal Spraying

In thermal spraying, uncoated substrates usually require roughening. As the most common roughening method, grit blasting increases the surface area and produces undercuts in almost all cases, which facilitate mechanical interlocking and thus promote the bonding between the substrate and coating. The effects of grit blasting parameters, i.e., the particle size, the blasting angle, the stand-off distance, and the pressure, on the resulting surface topography are investigated. Furthermore, the efficiency and wear behavior of the blasting media are analyzed. Influences of three different blasting media, corundum, alumina zirconia, and steel shot, on the surface roughening, are compared. By varying adjusted blasting parameters, different initial conditions (surface topography) are created. Subsequently, the substrate is coated, and the coating bond strength is measured. One of the main results of this publication is that alumina zirconia and steel grit show a longer lifetime than pure alumina as a blasting media. Moreover, it has been shown that the blasting parameters such as grain size, working pressure, and history (wear status) of the abrasive particles have a significant effect on the resulting surface topography. Additionally, systematical analysis in this study shows that the blasting parameters such as stand-off distance and blasting angle have a small influence on the results of the blasting process. Another important conclusion of this study is that the conventional surface parameters that have been analyzed in this study did not turn out to be suitable for describing the relationship between the surface topography of the substrate and resulting bond strength.

IMKS and IMMS : two methods for the production of plastic parts featuring metallic areas

Abstract The integration and combination of known technologies to one-step-processes is a promising way to implement enhancements to existing processes and products, as well as to new product developments. This approach is followed by two integrative process technologies that were developed by the Institute of Plastics Processing (IKV) at the RWTH Aachen University and the Surface Engineering Institute (IOT) at the RWTH Aachen University as part of the Cluster of Excellence “Integrative Production Technologies for High-Wage Countries”. In these processes, pure metals or metal alloys are joined to the injection moulded part, which potentially results in particular advantages referring to the electrical properties of the product. The integrated metal/plastic injection moulding (IMKS) represents the combination of injection moulding and metal die casting. The in-mould metal spraying (IMMS) combines the injection moulding with the thermal spraying of metal. In the following, the level of development of both methods is presented and future potentials are shown.

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.