PSI - Issue 34

H. Oberlercher et al. / Procedia Structural Integrity 34 (2021) 111–120 Hannes Oberlercher/ Structural Integrity Procedia 00 (2019) 000 – 000

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5

The dimensions of the three-point bending test specimens printed with the MF printing system, are 60 x 15 x 2 mm (length x width x thickness) following the testing standard ISO 14125 with the same line offset of approx. 0.9 mm. The layer height was chosen differently depending on the consolidation pressure and is listed in chapter 2.2. 15 test specimens were produced with the mentioned variants in Table 1. To analyse the influence of the consolidation time on the laminate with the 3DCP, different printing speeds were chosen (See Table 3). 2.5 Bending test procedure The material tests were carried out using 3-point bending tests according to test standard ISO 14125. The tests were conducted on a multi- testing machine Z020 (Zwick Roell). The manufacturer’s software testXpert II was used on the testing machine to initialize the test parameters and record the test data. 2.6 Microscopy The Binocular microscope Axio Lab.A1 (Zeiss, Oberkochen) was used to observe the fiber distribution as well as the void content of the test specimens. With a 2.0 MP Pixel-Fox digital camera (Dietermann & Heuser Solution, Greifenstein-Beilstein) the images were taken and processed with the manufacturer image measuring software.

3

Results

3.1 DSC and TGA analysis The DSC delivered us the glass transition temperature as well as the melting temperature of the MF CFC/PA6 material of the glass fiber reinforced fiber (GF) and the carbon reinforced fiber (CF) (See Table 4). With the results of the TGA measurement (see Table 5) and the rule of mixture (Equation 1), a fiber volume fraction of 35.0 ± 0.1% was calculated. The densities of carbon fibre as well as of the PA6 material were taken from the literature (Schürmann, 2007), (Baur, et al., 2019).

Table 4: Results of DSC measurement

Sample

Glass Transition Temperature [C°]

Melting Temperature [C°]

CF-PA6 GF-PA6

-

225 266 242

66 54

PA6

Table 5: Results of TGA measurement up to 600 C°

Sample CF-PA6 a CF-PA6 b

Sample weight [mg]

Residues [mg]

Residues [%]

8.008 8.159

3.778 3.868

47.17 47.41

Average carbon weight fraction

47.3 ± 0.1

= + = + (1 − )

Fiber volume fraction Fiber volume Matrix volume Fiber weight fraction Fiber density Matrix density

Equation 1