3D printing is nowadays used not only to rapidly produce prototypes, but is further applied for the fabrication of functional parts. Amongst other factors, processing parameters such as scaffolding angle and raster gap greatly affect the behaviour of such printed parts. Little attention has been given so far to the tribological behaviour of such prints. In this study the above mentioned parameters on the friction behaviour, in terms of friction coefficient and wear rate, is investigated. For this purpose the Fused Deposition Modelling is used as one of state of the art 3D printing methods. Graphite flakes were further added to the reference acrylonitrile butadiene styrene (ABS) matrix in an attempt to enhance the properties. Results show that the scaffolding angle only affects the behaviour, if a positive printing gap is appliedwhen a negative gap is used, the angle has no significant effect on properties. Maximum coefficient of friction at acceptable values of specific wear rates can be attained at a scaffolding angle of 90°with negative gap. The incorporation of graphite further increases the friction coefficient on the expense of reduced wear properties. Keywords: Fused Deposition Modelling / friction coefficient / specific wear rates / graphite flakes Heute wird die 3-D-Drucktechnologie nicht nur zur schnellen Herstellung von Prototypen eingesetzt, sondern unter anderem auch um Funktionsbauteile zu fertigen. Unter anderem spielen Prozessparameter, wie z. B. Druckwinkel und Rasterspalt eine entscheidende Rolle und beeinflussen das Verhalten der gedruckten Teile. Bislang wird in der Literatur wenig über das tribologische Verhalten solcher 3D Bauteile berichtet. In dieser Studie wird die Wirkung der oben genannten Parameter auf das Abriebverhalten, anhand von Reibungskoeffizient und Verschleißrate untersucht. Hierzu wird das Fused Deposition Modelling als eines der modernen 3D-Druckverfahren herangezogen. Bei dem Versuch das Reibungsverhalten zu verbessern, wurde dem Ausgangsmaterial Acrylnitril-Butadien-Styrol (ABS) Lammellengraphit zugegeben. Die Ergebnisse zeigen, dass der Druckwinkel nur bei positivem Rasterspalt eine Rolle spieltbei einem negativen Spalt, scheint der Winkel keinen signifikanten Einfluss zu haben. Maximale Reibwerte bei moderatem Verschleiß konnten bei einem Druckwinkel von 90°und negativem Spalt festgestellt werden. Der Zusatz von Graphit erhöhte maßgeblich den Reibungskoeffizienten, allerdings auf Kosten verringerter Verschleißeigenschaften.
The target of this study is to develop routes for processing Al–SiCp (SiC particulate) sheets with improved microstructures; namely, the uniform distribution of SiCp and minimized porosity throughout the whole material, thereby improving its mechanical properties. Al–SiCp composites reinforced with 5, 10, and 15 vol.% SiC and having three average sizes of 29, 17, and 8.5 µm were produced using a semi-automated stir-casting machine; finally, the bars were hot rolled to get the final sheet dimensions. The rolling steps were performed based on the results of thermomechanical simulations performed on the cast blocks. The first rolling steps were applied according to a safe rolling schedule to avoid cracking via encouraging dynamic recrystallization. The last rolling steps were performed to improve the hardness and strength of the metal matrix composites (MMCs). A refinement in grain size from an average of 420 µm in the as-cast condition to an average of about 85 µm after rolling was observed. Some heterogeneity in grain size was observed where the regions with larger, elongated grains were associated with the zones depleted by SiCp reinforcement. Reinforcing with SiCp led to a small increase in tensile strength of 10–20 MPa, and this was further improved to about 60 MPa and 110 MPa for the 5 and 10 vol.% SiCp conditions, respectively, after a T6 heat treatment.
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