Fabrication and Characterization of Standard 3D-Printed Specimen under Various Printing Speeds and Infill Densities

Abstract

An entry level average priced 3d-printer, the maker bot replicator mini+, was used to print dog bone specimens to conduct ultimate tensile strength, hardness and surface roughness testing. Average priced, polylactic acid (PLA) material was used as material to print dog bone specimens. Specimens were printed at various printing speeds of 90mm/s, 110mm/s, 130mm/s and 150mm/s and with various infill density levels of 55%, 75% and 95% to test the effect of part strength.

Tensile testing of the 3d-printed specimens showed that for higher density level 95% the tensile strength was higher which is 5.334kgf/mm², while at the 55% and 75% density level, the tensile strength was not much less which is 3.7220kgf/mm² and 4.1412kgf/mm², similarly the printing speed also produced low effect on the tensile strength. A Micro Vicker hardness testing machine was used to conduct hardness testing on printed specimen. For this type of testing the 95% density produced higher hardness of the specimen as compared to 55% and 75% density levels while with increasing the printing speed also produced the higher hardness. For surface roughness testing it was clearly showed that the 55% density produced lower roughness parameters (Ra, Rz, Rq) as compared to 75% and 95% density levels, which mean that the 55% specimens’ roughness values were less than that of 75% and 95%, while the highest printing speed, 150mm/s showed the lowest value of surface roughness.