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Not all PLA filaments are created equal: an experimental investigation

刊名：	Rapid prototyping journal
作者：	Schwartz, Johanna J.（Univ Washington, Dept Chem, Seattle, WA 98195 USA） Hamel, Joshua（Seattle Univ, Dept Mech Engn, Seattle, WA 98122 USA） Ekstrom, Thomas（Seattle Univ, Dept Mech Engn, Seattle, WA 98122 USA） Ndagang, Leticia（Seattle Univ, Dept Mech Engn, Seattle, WA 98122 USA） Boydston, Andrew J.（Univ Washington, Dept Chem, Seattle, WA 98195 USA）
刊号：	780C0104
ISSN：	1355-2546
出版年：	2020
年卷期：	2020, vol.26, no.7
页码：	1263-1276
总页数：	14
分类号：	TH
关键词：	Material testing；Design for additive manufacturing；Polymer properties
参考中译：
语种：	eng
文摘：	Purpose Additive manufacturing (AM) methods such as material extrusion (ME) are becoming widely used by engineers, designers and hobbyists alike for a wide variety of applications. Successfully manufacturing objects using ME three-dimensional printers can often require numerous iterations to attain predictable performance because the exact mechanical behavior of parts fabricated via additive processes are difficult to predict. One of that factors that contributes to this difficulty is the wide variety of ME feed stock materials currently available in the marketplace. These build materials are often sold based on their base polymer material such as acrylonitrile butadiene styrene or polylactic acid (PLA), but are produced by numerous different commercial suppliers in a wide variety of colors using typically undisclosed additive feed stocks and base polymer formulations. This paper aims to present the results from an experimental study concerned with quantifying how these sources of polymer variability can affect the mechanical behavior of three-dimensional printed objects. Specifically, the set of experiments conducted in this study focused on following: several different colors of PLA filament from a single commercial supplier to explore the effect of color additives and three filaments of the same color but produced by three different suppliers to account for potential variations in polymer formulation. Design/methodology/approach A set of five common mechanical and material characterization tests were performed on 11 commercially available PLA filaments in an effort to gain insight into the variations in mechanical response that stem from variances in filament manufacturer, feed stock polymer, additives and processing. Three black PLA filaments were purchased from three different commercial suppliers to consider the variations introduced by use of different feed stock polymers and filament processing by different manufacturers. An additional eight PLA filaments in varying colors were purchased from one of the three suppliers to focus on how color additives lead to property variations. Some tests were performed on unprocessed filament samples, while others were performed on objects three-dimensional printed from the various filaments. This study looked specifically at four mechanical properties (Young's modulus, storage modulus, yield strength and toughness) as a function of numerous material properties (e.g. additive loading, molecular weight, molecular weight dispersity, enthalpy of melting and crystallinity). Findings For the 11 filaments tested the following mean values and standard deviations were observed for the material properties considered:p(a) = 1.3 +/- 0.9% (percent additives),M-w = 98.6 +/- 16.4 kDa (molecular weight),= 1.33 +/- 0.1 (molecular weight dispersity),H-m = 37.4 +/- 7.2 J/g (enthalpy of melting) and = 19.6 +/- 2.1% (crystallinity). The corresponding mean values and standard deviations for the resulting mechanical behaviors were:E = 2,790 +/- 145 MPa (Young's modulus),E' = 1,050 +/- 125 MPa (storage modulus),S-y = 49.6 +/- 4.93 MPa (yield strength) andU(t) = 1.87 +/- 0.354 MJ/m<^>(3)(toughness). These variations were observed in filaments that were all manufactured from the same base polymer (e.g. PLA) and are only different in terms of the additives used by the manufacturers to produce different colors or different three-dimensional printing performance.