Fachbereich Maschinenbau und Mechatronik
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- Rapid prototyping (5)
- Rapid Prototyping (4)
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The manufacturing share of laser powder bed fusion (L-PBF) increases in industrial application, but still many process steps are manually operated. Additionally, it is not possible to achieve tight dimensional tolerances or low surfaces roughness. Hence, a process chain has to be set up to combine additive manufacturing (AM) with further machining technologies. To achieve a continuous workpiece flow as basis for further industrialization of L-PBF, the paper presents a novel substrate system and its application on L-PBF machines and post-processing. The substrate system consists of a zero-point clamping system and a matrix-like interface of contact pins to be substantially connected to the workpiece within the L-PBF process.
In times of short product life cycles, additive manufacturing and rapid tooling are important methods to make tool development and manufacturing more efficient. High-performance polymers are the key to mold production for prototypes and small series. However, the high temperatures during vulcanization injection molding cause thermal aging and can impair service life. The extent to which the thermal stress over the entire process chain stresses the material and whether it leads to irreversible material aging is evaluated. To this end, a mold made of PEEK is fabricated using fused filament fabrication and examined for its potential application. The mold is heated to 200 ◦C, filled with rubber, and cured. A differential scanning calorimetry analysis of each process step illustrates the crystallization behavior and first indicates the material resistance. It shows distinct cold crystallization regions at a build chamber temperature of 90 ◦C. At an ambient temperature above Tg, crystallization of 30% is achieved, and cold crystallization no longer occurs. Additional tensile tests show a decrease in tensile strength after ten days of thermal aging. The steady decrease in recrystallization temperature indicates degradation of the additives. However, the tensile tests reveal steady embrittlement of the material due to increasing crosslinking.
Schienenverkehrssysteme stehen in zunehmendem Wettbewerb, sowohl untereinander als auch mit anderen Verkehrsträgern. Als wichtiger Aspekt zur Steigerung der Kosteneffizienz wird die Digitalisierung des Betriebs und der Fahrzeuge betrachtet. Über eine Prognose der Ausfallwahrscheinlichkeit bzw. Restlebensdauer von Subsystemen können mittels Digitalisierung die Instandhaltungskosten gesenkt werden. Die geringen Fehlerraten im System Bahn machen die Nutzung besonderer Simulationstechniken notwendig. In diesem Beitrag wird gezeigt, wie sich die Subsystemverfügbarkeit aus den beobachteten Fehlerraten der Teilfunktionen vorhersagen lässt.