Navegando por Autor "Bohley, Martin"
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Artigo Micromachining of PMMA—manufacturing of burr-free structures with single-edge ultra-small micro end mills(Springer, 2018-03-10) Sousa, Fábio José Pinheiro; Reichenbach, Ingo G.; Bohley, Martin; Aurich, Jan C.Nowadays, the prototypes of microfluidic systems are generally produced via micromilling of thermoplastic polymethyl meth-acrylate (PMMA). The main limitations are the design of micro tools with diameters D ≤ 50 μm adapted for each application, and the understanding of the machining process itself. The objective of this research work is to contribute to mastering the process of PMMA micromilling with tool diameters D ≤ 50 μm on a 3-axes precision milling machine. For this purpose, the process design must include the complete process chain—from the CAD/CAM data up to the final structure geometry. The main requirements are the manufacture of microfluidic structures with Ra < 60 nm on the groove bottom and a top burr overhang h0 < 3 μm. Based on the experimental results, milling parameters were established and the influence of the tool geometry on the burr formation was determined. Finally, CAD/CAM machining strategies were recommendedArtigo Tool-life criteria and wear behavior of single-edge ultra-small micro end mills(Elsevier, 2019-01) Sousa, Fábio José Pinheiro; Reichenbach, Ingo G.; Bohley, Martin; Aurich, Jan C.Prototypes of microfluidic systems are often produced via micro milling, and the thermoplastic commonly used as substrate is polymethyl methacrylate (PMMA). A key challenge when manufacturing those systems is the confection of the micro tools, whose geometric design is limited by the current lack of knowledge about the process itself, especially for applications requiring micro tools with diameters D ≤ 50 μm. In terms of pro- ductivity, the tool-life capability is restrained by the machining conditions and the finish quality. Typical re- quirements for the manufacture of microfluidic structures with ultra-small micro mills are structures with Ra < 60 nm on the groove bottom and a top burr overhang h0 < 3 μm. This paper studies the tool-life cap- ability, including an analysis of the wear behavior of micro tools with diameters D ≤ 50 μm, providing the correlation between machining force signal, machining results (e.g. roughness or burr formation) as well as tool's characteristics before and after machining.