skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Optimizing the Tensile Strength for 3D Printed PLA Parts
This research investigates on how extruder nozzle temperature, model infill rate (i.e. density) and number of shells affect the tensile strength of three-dimensional polylactic acid (PLA) products manufactured with the fused deposition model technology. Our goal is to enhance the quality of 3D printed products using the Makerbot Replicator. In the last thirty years, additive manufacturing has been increasingly commercialized, therefore, it is critical to understand properties of PLA products to broaden the use of 3D printing. We utilize a Universal Tensile Machine and Quality Engineering to comprehend tensile strength characteristics of PLA. Tensile strength tests are performed on PLA specimens to analyze their resistance to breakage. Statistical analysis of the experimental data collected shows that extruder temperature and model infill rate (i.e. density) affect tensile strength.  more » « less
Award ID(s):
1431578
PAR ID:
10161472
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Solid Freeform Fabrication 2019: Proceedings of the 30th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, American Society of Mechanical Engineers)
    Abstract Fused deposition modeling (FMD) is considered one of the most common additive manufacturing methods for creating prototypes and small functional parts. Many researchers have studied Polylactic acid (PLA), Polycarbonate (PC), and Acrylonitrile butadiene styrene (ABS) as a material for fused deposition modeling printing. Among them, Polylactic Acid (PLA) is considered one of the most popular thermoplastic materials due to its low cost and biodegradable properties. In this study, silk PLA material was used. In Fused deposition modeling (FMD), the selection of printing parameters plays a pivotal role in determining the overall quality and integrity of the 3D-printed products. These parameters significantly influence the quality and strength of 3-D printed products. This study investigates the mechanical properties of silk-PLA printed specimens under different printing conditions, such as layer thickness, nozzle temperature, and print speed. All the tensile specimens were tested using ASTM D638 to characterize Young’s modulus and ultimate tensile strength. The thickness of the layers of tensile specimens was set to 0.1 mm, 0.15 mm, and 0.2 mm. The temperatures of the nozzle used during printing varied from 200°C, 210°C, and 220°C, whereas print speeds of 100 mm/s, 120 mm/s, and 140 mm/s were considered. The other printing parameters were kept consistent for all specimens. The result indicates tensile strength generally increases with increasing temperature of the nozzle, up to 220°C; however, a decline was observed in the average Young’s modulus value when the thickness of the layer increased from 0.10 mm to 0.20 mm. According to the results of the ANOVA analysis, the interaction between layer thickness, nozzle temperature, and printing speed significantly affects the tensile strength and Young’s modulus of Silk-PLA. This study reveals that nozzle temperature is the most critical parameter regarding the ultimate tensile strength and Young’s modulus, providing crucial insights for optimizing 3D printing parameters. 
    more » « less
  2. ; ; ; ; (, 3D Printing and Additive Manufacturing)
    Moisture absorption into hygroscopic/hydrophilic materials used in fused deposition modeling (FDM) can diminish desired mechanical properties. Sensitivity to moisture is dependent on material properties and environmental factors and needs characterization. In this article, moisture sensitivity of four grades of polylactic acid (PLA) filaments and four different ratios of PLA/polybutylene succinate (PBS) blended filaments were characterized through FDM printed American society for testing and materials (ASTM-D638) test samples after conditioning the filaments at different relative humidity levels. The tensile testing and scanning electron microscopy (SEM) of the samples' fracture surfaces revealed that PLA 4043D was the most moisture-sensitive among the chosen grades of PLA filaments. Through filament tension test and melt flow index (MFI) testing it was observed that moisture had a significant detrimental effect (20% reduction in tensile strength and 50% increase in MFI) on PLA 4043D filaments. Samples from moisture-conditioned PLA/PBS 75/25 blended filaments displayed a significant reduction (10%) in tensile strength. Moreover, the MFI of 75/25 filaments was increased with subsequent increases in moisture level. Investigation of tensile properties of ASTM samples made from four grades of PLA filaments exposed to room temperature and humidity conditions for 3 months showed an even more significant decrease in strength (ranging from 24% to 36%). 
    more » « less
  3. ; ; (, Journal of Applied Polymer Science)
    Matthew, A; Radhika, P; Vijaya, R (Ed.)
    Abstract In the present work, we report the effect of low‐temperature plasma treatment on thermal, mechanical, and biodegradable properties of polymer composite blown films prepared from carp fish scale powder (CFSP) and linear low‐density polyethylene (LLDPE). The CFSP was melt compounded with LLDPE using a filament extruder to prepare 1, 2, and 3 wt.% of CFSP in LLDPE polymer composite filaments. These filaments were further pelletized and extruded into blown films. The blown films extruded with 1, 2, and 3 wt.% of CFSP in LLDPE were tested for thermal and mechanical properties. It was observed that the tensile strength decreased with the increased loading content of CFSP, and 1% CFSP/LLDPE exhibited the highest tensile strength. To study the effect of low‐temperature plasma treatment, 1% CFSP/LLDP polymer composite with high tensile strength was plasma treated with O2and SF6gas before blow film extrusion. The 1% CFSP/LLDPE/SF6‐extruded blown films showed increased thermal decomposition, crystallinity, tensile strength, and modulus. This may be due to the effect of crosslinking by the plasma treatment. The maximum thermal decomposition rate, crystallinity %, tensile strength, and modulus obtained for 1% CFSP/LLDPE/SF6film were 500.02°C, 35.79, 6.32 MPa, and 0.023 GPa, respectively. Furthermore, the biodegradability study on CFSP/LLDPE films buried in natural soil for 90 days was analyzed using x‐ray fluorescence. The study showed an increase in phosphorus and calcium mass percent in the soil. This is due to the decomposition of the hydroxyapatite present in the CFSP/LLDPE biocomposite. 
    more » « less
  4. ; ; ; ; (, Journal of Computing and Information Science in Engineering)
    null (Ed.)
    Abstract 3D printing has been extensively used for rapid prototyping as well as low-volume production in aerospace, automotive, and medical industries. However, conventional manufacturing processes (i.e., injection molding and CNC machining) are more economical than 3D printing for high-volume mass production. In addition, current 3D printing techniques are not capable of fabricating large components due to the limited build size of commercially available 3D printers. To increase 3D printing throughput and build volume, a novel cooperative 3D printing technique has been recently introduced. Cooperative 3D printing is an additive manufacturing process where individual mobile 3D printers collaborate on printing a part simultaneously, thereby increasing printing speed and build volume. While cooperative 3D printing has the potential to fabricate larger components more efficiently, the mechanical properties of the components fabricated by cooperative 3D printing have not been systematically characterized. This paper aims to develop a data-driven predictive model that predicts the tensile strength of the components fabricated by cooperative 3D printing. Experimental results have shown that the predictive model is capable of predicting tensile strength as well as identifying the significant factors that affect the tensile strength. 
    more » « less
  5. ; ; ; ; (, Rapid Prototyping Journal)
    null (Ed.)
    Purpose The purpose of this study is to understand how printing parameters and subsequent annealing impacts porosity and crystallinity of 3D printed polylactic acid (PLA) and how these structural characteristics impact the printed material’s tensile strength in various build directions. Design/methodology/approach Two experimental studies were used, and samples with a flat vs upright print orientation were compared. The first experiment investigates a scan of printing parameters and annealing times and temperatures above the cold crystallization temperature ( T cc ) for PLA. The second experiment investigates annealing above and below T cc at multiple points over 12 h. Findings Annealing above T cc does not significantly impact the porosity but it does increase crystallinity. The increase in crystallinity does not contribute to an increase in strength, suggesting that co-crystallization across the weld does not occur. Atomic force microscopy (AFM) images show that weld interfaces between printed fibers are still visible after annealing above T cc , confirming the lack of co-crystallization. Annealing below T cc does not significantly impact porosity or crystallinity. However, there is an increase in tensile strength. AFM images show that annealing below T cc reduces thermal stresses that form at the interfaces during printing and slightly “heals” the as-printed interface resulting in an increase in tensile strength. Originality/value While annealing has been explored in the literature, it is unclear how it affects porosity, crystallinity and thermal stresses in fused filament fabrication PLA and how those factors contribute to mechanical properties. This study explains how co-crystallization across weld interfaces is necessary for crystallinity to increase strength and uses AFM as a technique to observe morphology at the weld. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email