PSI - Issue 34

H. Oberlercher et al. / Procedia Structural Integrity 34 (2021) 111–120

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Hannes Oberlercher/ Structural Integrity Procedia 00 (2019) 000 – 000

role is about 26 mm and is tempered with a 12 V 30 W cartridge heater. The rotation of the consolidation roller is transmitted to the CFC filament by the contact pressure. The distance between printing nozzle and the consolidation role is adjustable and is in this study about 18 mm. With a load cell (HBM PW4M), the current consolidation pressure in the printing process was measured. The printing nozzle has an offset of approx. 0.10 mm in the z-direction and serves as a guide nozzle for the filament. The hot-end is also tempered with a 12V 30W cartridge heater. For feeding and cutting the prepreg CFC-filament, a MF feeder/cutter of a Mark-one printer was used. For the printer control, the same procedure was used as for the MF printer which is described in chapter 2.2.

Heat shield

Cooling fan

Force

= Layer height

(b)

(a)

Figure 3: Self-developed CFC 3DCP

Printing conditions The temperatures of the CFF printing-nozzle tip was 242 C° and the temperature of the consolidation unit was about 220 C°. The printing-speed for the first test was about 15 mm/s and was continuously reduced for each sample variation (See Table 2). For analysing the influence of the printing-speed on the material, the printing speed was also continuously reduced for each sample variation (See Table 3). Only CFC-filament from MF was used. Table 2: Printing conditions CFC 3DCP with variation Variation Fiber orientation [mm] Pressure [N] Printing speed [mm/s] Nozzle-tip temperature Consolidation unit temperature A_CP 0° 0.125 1.9 15 242 C° 220 C° B_CP 0.105 2.7 C_CP 0.055 4.2

Table 3: Reduction of printing-speed of the 3DCP

[mm] 0.125 0.105

Variation

Printing-speed [mm/s]

A_CPL_V15 B_CPL_V10 C_CPL_V05

15 10

0.055

5

2.4 Specimen configuration For a first analysis of the CFC 3D-printed and 3DCP material, a single line and a laminate combination with seven lines and two layers were printed. The laminate combination had an offset of the individual lines of approx. 0.9 mm.