In order to process structural materials in additive manufacturing, a three-dimensional printing process with high deposition rate was developed. The process enables new design approaches for structural parts in automotive applications, combining continuous fibre-reinforced thermoplastics with short fibre-reinforced thermoplastics. For the combination of these materials, adhesion and the influence of the process parameters on adhesion is crucial. Within this study the adhesion has been measured in peel tests according to ASTM D, 6862, and the interface was investigated by optical microscopy. The adhesion process was evaluated by thermal imaging. The experiments showed that a good adhesion can be achieved during the printing process, but the continuous fibre-reinforced thermoplastic tape has to be preheated. In addition, an analytical model for the adhesion process has been introduced and validated with experimental results.

This paper reports the results of a study on twin-screw direct extrusion run at a screw speed of 120 rev/min to produce a composite pellet product which was used for an injection molding process and after that subjected to static tensile testing as well as hardness and specimen morphology examination. As filler, we used untreated Neuburg siliceous earth (NSE) marketed under trade names Silitin Z86 and Silitin V88 ranging from 10 to 60 wt% in a matrix made of high-density polyethylene (PE-HD) Hostalen GD 7255. The results demonstrate that Young's modulus and maximum tensile stress of the polyethylene composite with untreated Neuburg siliceous earth first decrease and then increase with increasing the filler's content. The addition of Silitin Z86 causes an increase in tensile stress at break while the addition of Silitin V88 leads to its decrease. Strain at maximum tensile stress of the tested molded pieces first increases with increasing the filler's content, but then starts to decrease. The tested composite molded pieces have lower strain at break as opposed to those without the filler. An increase in the filler's content leads to an increase in hardness of the tested specimens. The results of specimen morphology demonstrate that the filler is unevenly distributed in the polymer and reveals a strong tendency to agglomerate.

Der 3-D-Druck ist ein sehr stark wachsender Markt, welcher für Kunden und die Industrie völlig neue Produkt- und Fertigungsansätze eröffnet. Neue innovative Ansätze für die additive Fertigung von Kunststoffbauteilen entwickelt das Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik (IWU) in Zusammenarbeit mit der BMW Group. Auf Basis einer extrusionsbasierten Plastifiziereinheit zur Verarbeitung von Kunststoff-Standardgranulaten erfolgt in Kombination mit einer Pentapod 5-Achs- Parallelkinematik einer METROM-Werkzeugmaschine das 3-D-Drucken von Kunststoffbauteilen. Dabei werden bestehende Verfahrensgrenzen überschritten und eine neue Generation von 3-D-Druckverfahren mit deutlich gesteigerter Prozessgeschwindigkeit geschaffen.