The influence of process parameters on the impact resistance of 3D printed PLA specimens under water-absorption and heat-treated conditions

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pradeep Kumar Mishra ◽  
Senthil Ponnusamy ◽  
Mohan Satyanarayana Reddy Nallamilli
Keyword(s):  
Heat Treatment ◽  
Impact Strength ◽  
Water Absorption ◽  
Process Parameters ◽  
Impact Resistance ◽  
Post Processing ◽  
Content Type ◽  
Heat Treated ◽  
3D Printed ◽  
The Impact

Purpose The purpose of this paper is to analyse the effect of water absorption and heat treatment on the impact strength of three-dimensional (3D) printed Izod specimens. A low-cost post-processing technique is proposed to improve the impact strength of 3D printed parts substantially. Design/methodology/approach In the present work, the effect of water absorption and the heat-treatment on the impact resistance of 3D printed poly-lactic acid parts possessing different layer-height, build-orientation and raster-orientation was studied. Water absorption tests were conducted in distilled water and it was observed that the water- absorption in specimens follows the Fickian diffusion mechanism. A set of specimens was heat-treated at 120°C for 1 h using an induction furnace. Post water absorption and heat-treatment a significant increase in the impact resistance is noticed and especially a steep increase in impact resistance is observed in heat-treated specimens. Findings Experimental findings show that raster orientation played a major role in the impact resistance of a 3D printed structure in comparison to other process parameters. The order of influence of process parameters on the impact strength of specimens was disclosed by the mean effect plots. In terms of processing time and cost, the post-processing heat-treatment approach was found to be convenient compared to the water absorption technique. Originality/value This paper presents a new set of low-cost post-processing techniques (water-absorption and heat-treatment) for improving the impact strength of 3D printed specimens.

THE EFFECT OF LOW TEMPERATURES UPON THE IMPACT RESISTANCE OF STEEL CASTINGS

1930 ◽  
Vol 2 (5) ◽  
pp. 327-340
Author(s):  
R. W. Moffatt
Keyword(s):  
Heat Treatment ◽  
Low Temperatures ◽  
Room Temperature ◽  
Freezing Point ◽  
High Carbon Steel ◽  
Impact Resistance ◽  
Nickel Steel ◽  
Heat Treated ◽  
Steel Castings ◽  
The Impact

The investigation deals with the effect of low temperatures on the impact resistance of steel castings and forgings. Low, medium and high carbon steel castings and a few alloys of vanadium, nickel, and vanadium-nickel steel castings were examined. The metals were subjected to low temperatures, both before and after heat treatment. The temperatures for the tests varied from room temperatures to temperatures well below 0° F., so as to extend below the ordinary atmospheric range of temperatures found in northern climates.It was found that the impact resistances of the metals decreased for temperatures below the freezing point. For specimens, not heat treated, the impact resistance at − 40° F. may be only one-third to one-half of that at room temperature. Heat treatment increases the impact resistance at room temperatures and temperatures below the freezing point. The impact resistance at − 40° F. for the heat-treated metal compared favorably with the impact resistance of the untreated metal at room temperature, 68° F. Heat treatment may slightly lower the yield point and the ultimate tensile strength, but it increases the ductility and the impact resistance of the metal. By proper heat treatment of steel castings the impact resistance at − 40° F. may be brought over 300% higher than that of the untreated metal at that temperature.

The Causes of Low Impact Strength of T23 Steel Weld Joints

2015 ◽  
Vol 226 ◽  
pp. 103-106
Author(s):  
Janusz Adamiec ◽  
Izabela Pikos ◽  
Michał Stopyra
Keyword(s):  
Heat Treatment ◽  
Impact Strength ◽  
Weld Metal ◽  
Post Weld Heat Treatment ◽  
Weld Joints ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
The Impact ◽  
Welding Technique ◽  
Weld Heat

T23 is modern bainitic steel designed for use in supercritical boilers. According to producer’s data weldability of this steel is good enough to avoid post-weld heat treatment. However, some of the T23 weld joints in as-welded condition have not met the minimal ductility requirement. The impact test revealed significant differences between the joints in as-welded and heat treated condition. Metallographic and fractographic examinations have been conducted in order to explain those differences. The specimens with low impact strength were characterized by brittle fracture and non-tempered martensite presence in weld metal. It was concluded that avoiding formation of disadvantageous structure in weld metal requires conducting of post weld heat treatment or applying multi-pass welding technique with annealing run.

A Preliminary Analysis of the Effects of Process Parameters on the Impact Resistance of 3D Printed PETG and HIPS

2021 ◽  
pp. 524-534
Author(s):  
Massimo Martorelli ◽  
Vito Gallicchio ◽  
Antonio Gloria ◽  
Antonio Lanzotti
Keyword(s):  
Process Parameters ◽  
Preliminary Analysis ◽  
Impact Resistance ◽  
3D Printed ◽  
The Impact

scholarly journals Impact strength of 3D-printed polycarbonate

2020 ◽  
Vol 33 (1) ◽  
pp. 105-117
Author(s):  
Vries de ◽  
Roy Engelen ◽  
Esther Janssen
Keyword(s):  
Impact Strength ◽  
Vertical Wall ◽  
Impact Resistance ◽  
Surface Profile ◽  
Impact Testing ◽  
Fused Filament Fabrication ◽  
Layer Height ◽  
3D Printed ◽  
As Stress ◽  
The Impact

A vertical wall printed by Fused Filament Fabrication consists of a ribbed surface profile, due to the layer wise deposition of molten plastic. The notches between the printed layers act as stress concentrators and decrease its resistance to impact. This article shows the relation between impact strength and layer height by experimental data and finite element simulations of the stress intensity factor and the plastic zone near the tip of the notch. The impact resistance increased from 6 to 32 kJ/m2, when the layer height was decreased from 1.8 to 0.2 mm. When notches were removed by sanding, the samples did not fail any more during impact testing, resembling the behavior of smooth molded test bars. Tensile strength values up to 61 MPa were measured independent of layer height. Birefringence measurements were done to determine the actual stress levels, which ranged from 2 to 5 MPa.

Effect of Heat Treatment on the Impact Strength of Glass Fibre Reinforced Polypropylene

2002 ◽  
Vol 10 (8) ◽  
pp. 607-618 ◽  
Author(s):  
Jeng-Shyong Lin
Keyword(s):  
Heat Treatment ◽  
Impact Strength ◽  
Glass Fibre ◽  
Fibre Length ◽  
Testing Temperature ◽  
Polypropylene Composites ◽  
Heat Treated ◽  
Glass Fibre Reinforced ◽  
The Impact

The improvement of the interfacial adhesion of glass fibre reinforced polypropylene composites by heat treatment was studied. Polypropylene blended with short glass fibres was injection moulded. The moulded specimens were heat treated at various temperatures and for various times. Characterization of the mechanical properties of the samples was performed, including measurement of the critical fibre length. Impact tests were performed. The fracture surfaces were examined using a scanning electron microscope. The results show that the impact strength increased with the testing temperature. At 25°C, the impact strength was dominated by the fibre fracture mechanism. At temperatures above 120°C, it was strongly influenced by the PP matrix. At higher temperatures, the impact strength increased significantly because of the formation of extra cracks.

Infill parameters influence over the natural frequencies of ABS specimens obtained by extrusion-based 3D printing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Radu Constantin Parpala ◽  
Diana Popescu ◽  
Cristina Pupaza
Keyword(s):  
3D Printing ◽  
Natural Frequency ◽  
Process Parameters ◽  
Simulation Models ◽  
Response Surfaces ◽  
Frequency Function ◽  
Fe Model ◽  
Content Type ◽  
3D Printed ◽  
The Impact

Purpose The mechanical performances of 3D-printed parts are influenced by the manufacturing variables. Many studies experimentally evaluate the impact of the process parameters on specimens’ static and dynamic behavior with the aim of tailoring the mechanical response of the prints. However, this experimental approach is hampered by the very large number of parameters, 3D printers and materials, the development of computer simulation models being thus required. In the context, this study aims to fill a gap by experimentally investigating the influence of infill related parameters over the vibrations of 3D-printed specimens, as well as to propose and validate a parametric finite element (FE) model for the prediction of eigenfrequencies. Design/methodology/approach A generally applicable FE model is not yet available for the 3D printing technology based on the material extrusion process due to the large number of parameters settings that determine a large variability of outcomes. Hence, the idea of developing numerical simulation models that address sets of parameters and assess their impact on a certain mechanical property. For the natural frequency, the influence of the infill density and infill line width is studied in this paper. An FE script that automates the generation of the model geometry by using the considered set of parameters is developed and run. The results of the modal analysis are compared to the experimental values for validating the script. Findings Based on the experimental results, a linear regression between the weight of the part and the first natural frequency is established. The response surfaces indicate that the infill density is the most significant parameter of influence. The weight-frequency function is then used for the prediction of the natural frequency of specimens manufactured with other infill parameters and values, including different infill patterns. Practical implications As the malfunctions or mechanical damages can be caused by the resonant vibration of parts during use, this research develops a FE-parameterized model that evaluates and predicts the eigenfrequencies of 2D printed parts to prevent these undesirable events. The targeted functional applications are those in which 3D-printed polymer parts are used, such as drone arms or drone propellers. Originality/value This research studies the influence of process parameters on the natural frequency of 3D-printed polylactic acid specimens, a topic scarcely addressed in literature. It also proposes a new approach for the development of parameterized FE models for sets of parameters, instead of a general model, to reduce the time and resources allocated to the experimental tests. Such a model is provided in this paper for evaluating the influence of infill parameters on 3D prints eigenfrequency. The numerical model is validated for other infill settings.

Heat Treated Luffa - PLA Composites: Effect of Cyclic Moisture Absorption and Desorption on the Mechanical Properties

2018 ◽  
Vol 917 ◽  
pp. 42-46 ◽  
Author(s):  
Akshay Kakar ◽  
Elammaran Jayamani ◽  
Muhammad Khusairy bin Bakri ◽  
Soon Kok Heng
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Water Absorption ◽  
Moisture Absorption ◽  
Cold Water ◽  
Test Results ◽  
Heat Treated ◽  
The Impact

The goal of this study was to investigate the influence of cyclic hot and cold water absorption and desorption on the flexural and impact strengths of luffa – PLA biocomposites. PLA was reinforced with heat treated luffa fibers with the fiber loadings: 5 vol.%, 10 vol.%, 15 vol.% and 20 vol.%. Based on the test results the biocomposite with the highest flexural and impact strengths was selected for water absorption and desorption cycles. The biocomposites were subjected to 56 cycles of hot and cold water absorption and desorption. The biocomposites were tested for their strengths after every 14 cycles. The absorption and desorption decreased the flexural and impact strengths, affecting the impact strength more than the flexural strength.

Open hole tensile testing of 3D printed parts using in-house fabricated PLA filament

2020 ◽  
Vol 26 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Harshit K. Dave ◽  
Ashish R. Prajapati ◽  
Shilpesh R. Rajpurohit ◽  
Naushil H. Patadiya ◽  
Harit K. Raval
Keyword(s):  
Tensile Strength ◽  
Layer Thickness ◽  
Process Parameters ◽  
Geometrical Shape ◽  
Content Type ◽  
Fused Deposition ◽  
Open Hole ◽  
Raster Angle ◽  
3D Printed ◽  
The Impact

Purpose Fused deposition modeling (FDM) is being increasingly used in automotive and aerospace industries because of its ability to produce specimens having difficult geometrical shape. However, owing to lack of critical information regarding the reliability and mechanical properties of FDM-printed parts at various designs, the use of 3D printed parts in these industries is limited. Therefore, the purpose of this paper is to investigate the impact of process parameters of FDM on the tensile strength of open-hole specimen printed using in-house-fabricated polylactic acid (PLA). Design/methodology/approach In the present study, three process parameters, namely, raster angle, layer thickness and raster width, are selected for investigation of tensile strength. To produce the tensile specimens in the FDM machine, the PLA filament is used which is fabricated from PLA granules using a single-screw extruder. Further, the experimental values are measured and critically analysed. Failure modes under tests are studied using scanning electron microscopy (SEM). Findings Results indicate that the raster angle has a significant effect on the tensile strength of open-hole tensile specimen. Specimens built with 0° raster angle, 200-µm layer thickness and 500-µm raster width obtained maximum tensile strength. Originality/value In this work, a new concept of testing a plate that has a rectangular shape and a circular hole at the centre is tested. Open-hole tensile test standard ASTM D5766 has been implemented for the first time for the FDM process.

scholarly journals X-ray Shielding, Mechanical, Physical, and Water Absorption Properties of Wood/PVC Composites Containing Bismuth Oxide

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2212
Author(s):  
Worawat Poltabtim ◽  
Ekachai Wimolmala ◽  
Teerasak Markpin ◽  
Narongrit Sombatsompop ◽  
Vichai Rosarpitak ◽  
...  
Keyword(s):  
Impact Strength ◽  
Water Absorption ◽  
Attenuation Coefficient ◽  
Bismuth Oxide ◽  
Morphological Properties ◽  
Linear Attenuation Coefficient ◽  
X Rays ◽  
Equivalent Thickness ◽  
X Ray ◽  
The Impact

The potential utilization of wood/polyvinyl chloride (WPVC) composites containing an X-ray protective filler, namely bismuth oxide (Bi2O3) particles, was investigated as novel, safe, and environmentally friendly X-ray shielding materials. The wood and Bi2O3 contents used in this work varied from 20 to 40 parts per hundred parts of PVC by weight (pph) and from 0 to 25, 50, 75, and 100 pph, respectively. The study considered X-ray shielding, mechanical, density, water absorption, and morphological properties. The results showed that the overall X-ray shielding parameters, namely the linear attenuation coefficient (µ), mass attenuation coefficient (µm), and lead equivalent thickness (Pbeq), of the WPVC composites increased with increasing Bi2O3 contents but slightly decreased at higher wood contents (40 pph). Furthermore, comparative Pbeq values between the wood/PVC composites and similar commercial X-ray shielding boards indicated that the recommended Bi2O3 contents for the 20 pph (40 ph) wood/PVC composites were 35, 85, and 40 pph (40, 100, and 45 pph) for the attenuation of 60, 100, and 150-kV X-rays, respectively. In addition, the increased Bi2O3 contents in the WPVC composites enhanced the Izod impact strength, hardness (Shore D), and density, but reduced water absorption. On the other hand, the increased wood contents increased the impact strength, hardness (Shore D), and water absorption but lowered the density of the composites. The overall results suggested that the developed WPVC composites had great potential to be used as effective X-ray shielding materials with Bi2O3 acting as a suitable X-ray protective filler.

scholarly journals The effect of heat treatment and impact angle on the erosion behavior of nickel-tungsten carbide cold spray coating using response surface methodology

2021 ◽  
Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi
Keyword(s):  
Heat Treatment ◽  
Response Surface Methodology ◽  
Mass Loss ◽  
Tungsten Carbide ◽  
Response Surface ◽  
Spray Coating ◽  
Impact Angle ◽  
Control Factors ◽  
Heat Treated ◽  
The Impact

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.

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