PSI - Issue 37

Tiago Domingues et al. / Procedia Structural Integrity 37 (2022) 847–856 Tiago Domingues et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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Figure 6 --(a) Components produced in PEI; (b) Components produced in PEEK

Regarding the components produced in PEI, it was necessary to perform four iterations to reach an acceptable part. The first print failed due to an excessive fill print speed, of 80 mm/s, which resulted in insufficient bonding between the layers. The second try failed due to a notch that defected the filament, causing the extrusion process to stop. Additionally, in the second print it was noted under extrusion. The third print was completed, but the produced part was of poor quality due to under-extrusion effects. Finally, after adjusting the printer feed rate, a part was produced successfully. The final part still had a ringing effect which means that the printer has excessive vibrating effects and had some discoloration which would be due to some moisture in the filament. Other than that, all the parts had a constant dimensional deviation from the 3D CAD model, as shown in Table 3, which means that a software adjustment must be made to compensate for this phenomenon. The parameters used for printing the best produced PEI part were extrusion temperature of 370 ºC, bed temperature of 200 ºC, chamber temperature of 100 ºC aided by the use of the radiation system, a perimeter speed of 30mm/s, a filling speed of 30 mm/s, an infill velocity of 30 mm/s, an infill of 10 %, and 4 top and bottom solid layers.

Table 3 – Results and observatiosn from PEI produced components

Part Identification

X (Dimension/ Variation) 19.5mm/ -2.5%

Y (Dimension/ Variation) 20.3mm/ 1.5%

Z (Dimension/ Variation) Not Applicable

Main Observations

1

Failure due to excessive infill speed - 80mm/s. Failure due to filament defect; Infill under extrusion noted.

2

19.6mm/ -2.0%

20.5mm/ 2.5%

Not Applicable

3 4

19.6mm/ -2.0% 19.7mm/ -1.5%

20.3mm/ 1.5% 20.4mm/ 2.0%

19.9mm/ 0.5% 19.9mm/ 0.5%

Under extrusion noted.

Ringing and humidity effects noted.

As for the PEEK parts, three components were produced until reaching a part considered acceptable. The first tentative part was a complete print but exhibited discoloration and warping phenomena which were believed to be due to excessive temperature in the extrusion process. After lowering the extruder temperature, a second part was produced which presented phenomena of discoloration and warping, although less significant than the previous part, and a slight delamination. For the next iteration the radiation system was turned on, and the final piece was produced with a final shape which was considered successful although it had two small delaminations, and some small ringing and warping effects. Additionally, as for the produced PEI components, all the parts had a constant dimensional deviation from the 3D CAD model, as shown in Table 4, which means that a software adjustment must be made to compensate for this phenomenon.