The impact of process parameters on mechanical properties of parts fabricated in PLA with an open-source 3-D printer
Abstract
Purpose
This study aims to quantify the ultimate tensile strength and the nominal strain at break (ɛf) of printed parts made from polylactic acid (PLA) with a Replicating Rapid prototyper (Rep-Rap) 3D printer, by varying three important process parameters: layer thickness, infill orientation and the number of shell perimeters. Little information is currently available about mechanical properties of parts printed using open-source, low-cost 3D printers.
Design/methodology/approach
A computer-aided design model of a tensile test specimen was created, conforming to the ASTM:D638. Experiments were designed, based on a central composite design. A set of 60 specimens, obtained from combinations of selected parameters, was printed on a Rep-Rap Prusa I3 in PLA. Testing was performed using a JJ Instruments – T5002-type tensile testing machine and the load was measured using a load cell of 1,100 N.
Findings
This study investigated the main impact of each process parameter on mechanical properties and the effects of interactions. The use of a response surface methodology allowed the proposition of an empirical model which connects process parameters and mechanical properties. Even though results showed a high variability, additional ideas on how to understand the impact of process parameters are suggested in this paper.
Originality/value
On the basis of experimental results, it is possible to obtain practical suggestions to set common process parameters in relation to mechanical properties. Experiments discussed in the present paper provide a variety of data and insight regarding the relationship among the main process parameters and the stiffness and strength of fused deposition modeling-printed parts made from PLA. In particular, this paper underlines the shortage in existing literature concerning the impact of process parameters on the elastic modulus and the strain to failure for the PLA. The experimental data produced show a good degree of compliance with analytical formulations and other data found in literature.
Keywords
Acknowledgements
The authors would like to express sincere gratitude to the anonymous referees for their constructive comments on the paper; these have helped to improve the quality of the paper significantly. The authors gratefully acknowledge Prof Biagio Palumbo and Antonio Lepore (University of Naples Federico II) for their suggestions and useful insights about statistical analysis. The authors also thank Luciano Cortese (Istituto di Ricerche sulla Combustione, CNR, Napoli, Italy) for the SEM images of the samples.
Citation
Lanzotti, A., Grasso, M., Staiano, G. and Martorelli, M. (2015), "The impact of process parameters on mechanical properties of parts fabricated in PLA with an open-source 3-D printer", Rapid Prototyping Journal, Vol. 21 No. 5, pp. 604-617. https://doi.org/10.1108/RPJ-09-2014-0135
Publisher
:Emerald Group Publishing Limited
Copyright © 2015, Emerald Group Publishing Limited