Mechanical Performance of 3D Printed PLA and ABS

This paper analyses the mechanical performance of pieces manufactured using PLA and ABS, the most commonly used materials in material extrusion 3D printing technologies. PLA is a biodegradable polymer derived from lactic acid. The main advantage of this material is how easy it is to use in 3D printing and the good results it delivers. It requires a lower extrusion temperature than ABS, it does not suffer significant distortions during printing and it adheres well to the platform, which means it does not require a heated base. Neither does it give off a bad smell or toxic vapours during printing. It must not be used for parts that have to withstand high temperatures because PLA tends to warp at over 60 °C. ABS is a thermoplastic that is extremely resistant to impact, abrasion, and chemical elements. In 3D printing, it is the most used material after PLA. Its good mechanical properties, resistance to temperature, low price, moderate flexibility, long service life and range of melting temperatures make this material an excellent option for manufacturing all manner of parts using FDM technologies, above all, parts that have to withstand cyclical loads and temperature changes. However, it is not suitable for all applications as it presents problems of contraction and warping during printing, tends to peel away from the platform, and tends to give off toxic gases. Table 1 shows the data provided by the manufacturer for the filaments of the two materials used. As can be seen, PLA is more rigid and has a greater tensile strength while ABS is more ductile. However, the impact strength of ABS is far greater (320 J/m against 220 J/m (Notched Izod Impact)), one of the main properties that differentiates it from other plastics.
The additive manufacturing equipment to be used is the Prusa I3 Aluminium printer (Prague, Czech Republic) (Figure 2a), which employs FFF technology. The Cura software (Ultimaker, Geldermalsen, The Netherlands) is used to export the three-dimensional models of the samples to G-code. The main technical characteristics of the FDM printer are defined in Table 2. The tests are carried out using a HOYTOM HM-D 100 kN model universal testing machine (Leioa, Spain) (Figure 2b).