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

848

2

1. Introduction In recent years, additive manufacturing of plastics has seen a growth in its use accompanied by new technological developments which have broadened the range of possibilities offered by these technologies (Attaran, 2017). One of the new developments has been the introduction of new printing materials for the fusion filament fabrication (FFF) method, such as high-performance thermoplastics, which are plastics with higher working temperatures as well as better chemical and mechanical properties compared to standard printing plastics (Kemmish, 2011). To study the properties and characteristics of the materials produced by the FFF process in these high-performance thermoplastics, it was established the objective of producing an equipment capable of producing parts in Polyether Ether Ketone (PEEK) and Polyetherimide (PEI).

Nomenclature ABS

Acrylonitrile butadiene styrene

CAD Computer-aided design FDM Fusion Deposition Modelling FFF Fused Filament Fabrication PEEK Polyether Ether Ketone PEI Polyetherimide PETG Polyethylene terephthalate glycol PLA Polylactic acid SLA Stereolithography SLS Selective layer sintering

1.1. Fused Filament Fabrication Besides the FFF method there are several types of other methods for producing plastics parts by additive manufacturing, such as stereolithography (SLA) or Selective layer sintering (SLS). For this study, the FFF method was chosen because of its low cost and the high availability of parts and equipment materials. The FFF method, which may also be referred to as Fused deposition modeling (FDM), as it was trademarked by the company Stratasys, is a method consisting in extruding a continuous filament of thermoplastic to gradually form a part layer by layer (Solomon et al., 2021). The equipment used to produce parts by this type of method have five fundamental constituent components, although there may be some variation depending on the purpose of each equipment. The extruder, which has two main parts, the hotend responsible for heating and melting the extruded filament, and a motor responsible for pushing of the filaments and materializing the extrusion process itself. Then there is the Cartesian axes which can move the extruder and the bed according to the generated G-code in order to produce the desired part. The build plate which is a heated surface in which the extruded material will be deposited. And finally, in some 3D printers, there is a chamber that encloses the print volume to have a controlled printing environment (J. Swansom et al., 2004; Soctt Crump, 1989).

1.2. High Performance Thermoplastics

FFF printers most commonly produce parts in materials such as Polylactic Acid (PLA), Polyethylene terephthalate glycol (PETG) or Acrylonitrile butadiene styrene (ABS), among others, but there are applications where more demanding requirements create the need for parts that are additively manufactured from a better class of polymers called high-performance plastics. High-performance plastics are materials which by definition have a working temperature above 150 ºC, along with better chemical and mechanical properties when compared to common plastics (Parker et al., 2000). For this work it were chosen PEEK and PEI ULTEM 1010, as reference for high-performance thermoplastics due their higher availability. Table 1 shows that these high-performance plastics