Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Boron-doped CVD diamond micro-end mills for machining titanium
    ( 2018)
    Uhlmann, Eckart
    ;
    Polte, Mitchel
    ;
    Polte, Julian
    ;
    Oberschmidt, Dirk
    In industry micro-milling tools made of cemented carbide are widely used. However, these micro-milling tools suffer from fast and random tool breakage during the machining of hard to machine materials. Therefore, in preliminary work micro-milling tools with cutting edges made of boron doped chemical vapour deposition (bdCVD) diamond were developed. In this work new micro-milling tools were successfully applied for machining titanium grade 2. Comprehensive cutting tests were carried out to analyse the influence of the spindle speed n, the feed per tooth ft, and the depth of cut ap on the surface roughness. Further experiments addressed the wear behaviour of the developed micro-milling tools. After a path length lc of 10 m a maximum width of flank wear land VBmax of 29 µm were observed.
  • Publication
    Diamond burnishing for mould and die industry
    ( 2018)
    Uhlmann, Eckart
    ;
    Oberschmidt, Dirk
    ;
    Guhde, Sebastian
    ;
    Polte, Mitchel
    ;
    Polte, Julian
    Special ultra-precision processes are necessary to machine surfaces for optical applications with required surface roughness Ra < 30 nm. The use of ultra-precision cutting results in low feed f and significantly reduced cost-efficiency. Diamond burnishing can be a cost-effective alternative. The process reduces the surfaces roughness and generates residual stress, which is advantageous for the workpiece's fatigue strength. However, diamond burnishing is mostly used for post-processing of rotating parts. Applications of diamond burnishing by linear motion, e. g. in mould and die making, are not common. The article shows first investigations to manufacture surfaces with optical quality on milled parts made of steel X37CrMoV5-1, copper CW008A, brass CW612N and aluminium 5083. The experiments were carried out on a 5-axis milling machine tool PFM 4024-5D, PRIMACON GMBH, PeiÃenberg, Germany. The feed velocity, the penetration depth, and the stepover were varied as input para meters. Vickers hardness and the surfaces roughness were measured as reference criteria. Thus, the ability for the surface improvement by diamond burnishing of complex shaped surfaces could be shown.
  • Publication
    Manufacturing, replication and assessment of microfluidics for blood plasma separation
    ( 2016)
    Uhlmann, Eckart
    ;
    Hein, Christoph
    ;
    Polte, Mitchel
    ;
    Polte, Julian
    ;
    Spielvogel, Anja
    ;
    Huth-Herms, Katrin
    ;
    Oberschmidt, Dirk
    Point of care diagnostics gain importance with regard to novel diagnostic techniques. Future applications, for example based on cell-free DNA, are prenatal or cancer diagnostics. With regard to these methods a large influence of natural blood degradation during full blood storage and transport before laboratory based separation restricts possible applications. With a point of care plasma separation device, the plasma can be separated from full blood directly after blood collection. Thus, diagnostic markers remain undamaged and allow a highly specific detection. Targeting microfluidics for point-of-care blood plasma separation, this work presents the development of a microfluidic blood plasma separation device along a novel process chain. Besides system design and manufacturing technologies for prototypes, the development of technologies for replication, closure of microfluidics and affecting of surface properties are under the special scope of this investigation.