scholarly journals On the Relationship between Mechanical Properties and Crystallisation of Chemically Post-Processed Additive Manufactured Polylactic Acid Pieces

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 941 ◽  
Author(s):  
A.P. Valerga ◽  
S.R. Fernandez-Vidal ◽  
F. Girot ◽  
A.J. Gamez

Nowadays, improvement of the surface finish of parts manufactured by fused deposition modelling is a well-studied topic. Chemical post-treatments have proven to be the best technique in terms of time consumption and smoothness improvement. However, these treatments modify the structure of the material and, consequently, its mechanical properties. This relationship was studied in this work. In this case, on the basis of a previous study on crystallisation, polylactic acid pieces were subjected to different post-treatments to evaluate their effects on the sample’s mechanical properties, i.e., tensile strength and hardness. Models were obtained according to their percentage of crystallisation, which was related to the different treatments, as well as immersion time. Dramatic changes were obtained within a wide range of material behaviour with some treatments. Specifically, changes were obtained in the maximum stress (from 55 to 20 MPa), in elongation (from 3% to 260%), and in the hardness scale (Shore D to A).

2021 ◽  
Vol 63 (1) ◽  
pp. 73-78
Author(s):  
Pulkin Gupta ◽  
Sudha Kumari ◽  
Abhishek Gupta ◽  
Ankit Kumar Sinha ◽  
Prashant Jindal

Abstract Fused deposition modelling (FDM) is a layer-by-layer manufacturing process type of 3D-printing (3DP). Significant variation in the mechanical properties of 3D printed specimens is observed because of varied process parameters and interfacial bonding between consecutive layers. This study investigates the influence of heat treatment on the mechanical strength of FDM 3D printed Polylactic acid (PLA) parts with constant 3DP parameters and ambient conditions. To meet the objectives, 7 sets, each containing 5 dog-bone shaped samples, were fabricated from commercially available PLA filament. Each set was subjected to heat treatment at a particular temperature for 1 h and cooled in the furnace itself, while one set was left un-treated. The temperature for heat treatment (Th) varied from 30 °C to 130 °C with increments of 10 °C. The heat-treated samples were characterized under tensile loading of 400 N and mechanical properties like Young’s modulus (E), Strain % ( ε ) and Stiffness (k) were evaluated. On comparing the mechanical properties of heat-treated samples to un-treated samples, significant improvements were observed. Heat treatment also altered the geometries of the samples. Mechanical properties improved by 4.88 % to 10.26 % with the maximum being at Th of 110 °C and below recrystallization temperature (Tr) of 65 °C. Deformations also decreased significantly at higher temperatures above 100 °C, by a maximum of 36.06 %. The dimensions of samples showed a maximum decrease of 1.08 % in Tr range and a maximum decrease of 0.31 % in weight at the same temperature. This study aims to benefit the society by establishing suitable Th to recover the lost strength in PLA based FDM 3D printed parts.


2020 ◽  
Vol 22 (4) ◽  
pp. 895-908
Author(s):  
M. Ouhsti ◽  
B. El Haddadi ◽  
S. Belhouideg

Abstract3D polymer-based printers have become easily accessible to the public. Usually, the technology used by these 3D printers is Fused Deposition Modelling (FDM). The majority of these 3D printers mainly use acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) to fabricate 3D objects. In order for the printed parts to be useful for specific applications, the mechanical properties of the printed parts must be known. The aim of this study is to determine the tensile strength and elastic modulus of printed materials in polylactic acid (PLA) according to three important printing parameters such as deposition angle, extruder temperature and printing speed. The central composite design (CCD) was used to reduce the number of tensile test experiments. The obtained results show that the mechanical properties of printed parts depend on printing parameters. Empirical models relating response and process parameters are developed. The analysis of variance (ANOVA) was used to test the validity of models relating response and printing parameters. The optimal printing parameters are determined for the desired mechanical properties.


2021 ◽  
Vol 58 (2) ◽  
pp. 176-184
Author(s):  
Constantin-Romica Stoica ◽  
Raluca Maier ◽  
Anca Istrate ◽  
Andrei-Cristian Mandoc

The paper presents the study on the static mechanical properties of PLA (Polylactic Acid) produced with entry-level additive technologies using three printing directions. During the experimental work were tested a total of 15 �dog bone� ASTM D638-14 standard specimens made from additively manufactured polymer (PLA) through FDM (Fused Deposition Modelling) technique, where the material and rectilinear pattern infill geometry and infill percentage of 100% were constant and the printing orientation was varied. Usually technical data sheets that are delivered by filament materials producers include the most satisfactory data which are valid for only one specific printing direction. The printing direction is deliberately selected, in such way that the best material characteristics are achieved. In addition to this matter, as the additive manufacturing market grew significantly in the past couple of years, the filament production market showed a consequential growth. The aftermath of this expansion had a direct impact towards the quality and costs of the filaments used for 3D printing, in order to satisfy both the low-end and high-end users. Therefore, in this frame, the present research provides entry-level additively manufactured PLA performances showing significant changes depending on the different printing directions and determine the build orientation influence on the mechanical properties, in the aim of providing aid for both mechanical designer and product manufacturer at the stage of the printed product mechanical properties.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2289
Author(s):  
Nishata Royan Rajendran Royan ◽  
Jie Sheng Leong ◽  
Wai Nam Chan ◽  
Jie Ren Tan ◽  
Zainon Sharmila Binti Shamsuddin

As one of the fastest-growing additive manufacturing (AM) technologies, fused deposition modelling (FDM) shows great potential in printing natural fibre-reinforced composites (NFRC). However, several challenges, such as low mechanical properties and difficulty in printing, need to be overcome. Therefore, the effort to improve the NFRC for use in AM has been accelerating in recent years. This review attempts to summarise the current approaches of using NFRC as a feeder for AM. The effects of fibre treatments, composite preparation methods and addition of compatibilizer agents were analysed and discussed. Additionally, current methods of producing feeders from NFRCs were reviewed and discussed. Mechanical property of printed part was also dependent on the printing parameters, and thus the effects of printing temperature, layer height, infill and raster angle were discussed, and the best parameters reported by other researchers were identified. Following that, an overview of the mechanical properties of these composites as reported by various researchers was provided. Next, the use of optimisation techniques for NFRCs was discussed and analysed. Lastly, the review provided a critical discussion on the overall topic, identified all research gaps present in the use of NFRC for AM processes, and to overcome future challenges.


2016 ◽  
Vol 9 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Bolin Huang ◽  
S.H. Masood ◽  
Mostafa Nikzad ◽  
Prabhu Raja Venugopal ◽  
Adhiyamaan Arivazhagan

TEM Journal ◽  
2020 ◽  
pp. 966-970
Author(s):  
Damir Hodžić ◽  
Adi Pandžić ◽  
Ismar Hajro ◽  
Petar Tasić

Widely used additive manufacturing technique for plastic materials is Fused Deposition Modelling (FDM). The FDM technology has gained interest in industry for a wide range of applications, especially today when large number of different materials on the market are available. There are many different manufacturers for the same FDM material where the difference in price goes up to 50%. This experimental study investigates possible difference in strength of the 3D printed PLA material of five different manufacturers. All specimens are 3D printed on Ultimaker S5 printer with the same printing parameters, and they are all the same colour.


Sign in / Sign up

Export Citation Format

Share Document