The coating of highly stressed components with chemical vapor deposition (CVD) diamond can extend their lifetime. In particular, the combination of steel substrates with diamond layers would find many applications in industrial production. However, there are some challenges, for example, the high mismatch in the thermal expansion between steel and diamond, which commonly leads to the delamination of the coating. Thus, a pre-treatment of the substrate surface is needed. Particle blasting has been established in some studies as a suitable process. However, apart from particle residues in the surface of the substrate, these surfaces have a stochastic character, which limits their reproducibility and modification options. This paper presents some instructions for the recording and derivation of defined properties of those surfaces. The conversion of characteristic surface features into quantitative process parameters could serve as the foundation for the manufacturing of deterministic microstructures, especially those produced by ultrasonic vibration superimposed machining. This should increase the reproducibility and the possibilities of the modification with regard to the structural shaping of the functional surface. The design was developed using both a kinematic surface simulation tool as well as a finite elements analysis for the cooling process of the coating–substrate–composite. A high accordance with real finished surfaces was achieved.
In the sheet metal forming industry lubricants are applied in forming processes to expand the technological boundaries by reducing friction and wear. The friction between tool and sheet metal is crucial to the deep drawing process. Due to economic and ecological reasons the aim of the manufacturers is to reduce or even avoid the use of lubricants. Consequently, this approach enables both a shortening of the process chains and an essential saving of resources. The advantages of structured forming tools in lubricated processes concerning the reduction of the coefficient of friction by the appearance of lubricating micro pockets are well-known. However, without using any lubricant this effect does not work. In this case the contact area is reduced by structuring the forming tool which affects the tribological system.In this paper the influence of microstructures with different geometries and surface treatments (uncoated / a-C:H:Si-coating) on the coefficient of friction in dry metal forming of the alloy AA5182 is compared to the frictional behaviour of unstructured forming tools using lubricant as reference. Before coating, the forming tools are machined by milling to generate tribologically effective microstructures. With the use of a strip drawing plant the effects of different surface microstructures and materials on the coefficient of friction are investigated.
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