Abstract:Three-dimensional (3D) printing is a manufacturing technology which creates three-dimensional objects layer-by-layer or drop-by-drop with minimal material waste. Despite the fact that 3D printing is a versatile and adaptable process and has advantages in establishing complex and net-shaped structures over conventional manufacturing methods, the challenge remains in identifying the optimal parameters for the 3D printing process. This study investigated the influence of processing parameters on the mechanical pr… Show more
“…Thus, when a wide range of PSs are considered, a quadratic effect on strength and stiffness properties with PS may be expected, exhibiting an optimal speed where layers are held above T g longer and defects are not induced by high speed. The quadratic relationship with PS has been observed in some work with PLA carbon fiber composite, finding tensile strength was optimal at 55 mm/s and decreased when printed faster or slower (Lee and Wu, 2020). In this work, significant PS effects were quadratic, suggesting an optimal PS depending on the mechanical property being maximized.…”
Section: Discussionmentioning
confidence: 81%
“…It has been hypothesized that increased PSs would result in less time for previously printed layers to cool before being reheated by the following molten layer, and the ability to influence cooling time has significant effect on mechanical properties (Bellehumeur et al , 2004). This has been expected to hold the temperature above the glass transition temperature longer, allowing for entanglement of polymer chains and increasing stiffness and strength (Lee and Wu, 2020). This effect has been observed in some work with ABS (Patibandla and Mian, 2020) and PLA (Kuznetsov et al , 2020).…”
Section: Discussionmentioning
confidence: 99%
“…Similarly in ABS, higher extrusion temperatures predicted increased tensile modulus (Attolico et al , 2020; Patibandla and Mian, 2020), yield strength (Patibandla and Mian, 2020) and tensile strength (Abbott et al , 2018; Attolico et al , 2020). In printed PLA carbon fiber composites, it was observed that the lowest printing temperatures (220–240°C) had caused the highest tensile strength, despite the expectation that higher temperatures would increase chain entanglement and strength (Lee and Wu, 2020). It was suggested that higher temperatures were causing material degradation and reducing the strength.…”
Purpose
The fused filament fabrication (FFF) process is an additive manufacturing technique used in engineering design. The mechanical properties of parts manufactured by FFF are influenced by the printing parameters. The mechanical properties of rigid thermoplastics for FFF are well defined, while thermoplastic elastomers (TPE) are uncommonly investigated. The purpose of this paper is to investigate the influence of extruder temperature, bed temperature and printing speed on the mechanical properties of a thermoplastic elastomer.
Design/methodology/approach
Regression models predicting mechanical properties as a function of extruder temperature, bed temperature and printing speed were developed. Tensile specimens were tested according to ASTM D638. A 3×3 full factorial analysis, consisting of 81 experiments and 27 printing conditions was performed, and models were developed in Minitab. Tensile tests verifying the models were conducted at two selected printing conditions to assess predictive capability.
Findings
Each mechanical property was significantly affected by at least two of the investigated FFF parameters, where printing speed and extruder temperature terms influenced all mechanical properties (p < 0.05). Notably, tensile modulus could be increased by 21%, from 200 to 244 MPa. Verification prints exhibited properties within 10% of the predictions. Not all properties could be maximized together, emphasizing the importance of understanding FFF parameter effects on mechanical properties when making design decisions.
Originality/value
This work developed a model to assess FFF parameter influence on mechanical properties of a previously unstudied thermoplastic elastomer and made property predictions within 10% accuracy.
“…Thus, when a wide range of PSs are considered, a quadratic effect on strength and stiffness properties with PS may be expected, exhibiting an optimal speed where layers are held above T g longer and defects are not induced by high speed. The quadratic relationship with PS has been observed in some work with PLA carbon fiber composite, finding tensile strength was optimal at 55 mm/s and decreased when printed faster or slower (Lee and Wu, 2020). In this work, significant PS effects were quadratic, suggesting an optimal PS depending on the mechanical property being maximized.…”
Section: Discussionmentioning
confidence: 81%
“…It has been hypothesized that increased PSs would result in less time for previously printed layers to cool before being reheated by the following molten layer, and the ability to influence cooling time has significant effect on mechanical properties (Bellehumeur et al , 2004). This has been expected to hold the temperature above the glass transition temperature longer, allowing for entanglement of polymer chains and increasing stiffness and strength (Lee and Wu, 2020). This effect has been observed in some work with ABS (Patibandla and Mian, 2020) and PLA (Kuznetsov et al , 2020).…”
Section: Discussionmentioning
confidence: 99%
“…Similarly in ABS, higher extrusion temperatures predicted increased tensile modulus (Attolico et al , 2020; Patibandla and Mian, 2020), yield strength (Patibandla and Mian, 2020) and tensile strength (Abbott et al , 2018; Attolico et al , 2020). In printed PLA carbon fiber composites, it was observed that the lowest printing temperatures (220–240°C) had caused the highest tensile strength, despite the expectation that higher temperatures would increase chain entanglement and strength (Lee and Wu, 2020). It was suggested that higher temperatures were causing material degradation and reducing the strength.…”
Purpose
The fused filament fabrication (FFF) process is an additive manufacturing technique used in engineering design. The mechanical properties of parts manufactured by FFF are influenced by the printing parameters. The mechanical properties of rigid thermoplastics for FFF are well defined, while thermoplastic elastomers (TPE) are uncommonly investigated. The purpose of this paper is to investigate the influence of extruder temperature, bed temperature and printing speed on the mechanical properties of a thermoplastic elastomer.
Design/methodology/approach
Regression models predicting mechanical properties as a function of extruder temperature, bed temperature and printing speed were developed. Tensile specimens were tested according to ASTM D638. A 3×3 full factorial analysis, consisting of 81 experiments and 27 printing conditions was performed, and models were developed in Minitab. Tensile tests verifying the models were conducted at two selected printing conditions to assess predictive capability.
Findings
Each mechanical property was significantly affected by at least two of the investigated FFF parameters, where printing speed and extruder temperature terms influenced all mechanical properties (p < 0.05). Notably, tensile modulus could be increased by 21%, from 200 to 244 MPa. Verification prints exhibited properties within 10% of the predictions. Not all properties could be maximized together, emphasizing the importance of understanding FFF parameter effects on mechanical properties when making design decisions.
Originality/value
This work developed a model to assess FFF parameter influence on mechanical properties of a previously unstudied thermoplastic elastomer and made property predictions within 10% accuracy.
“…Therefore, the geometrical arrangement of the structural material within one layer and the orientation of the layers of the material relative to the direction of the mechanical load are important parameters for controlling the strength of the final products, along with the type of thermoplastic polymer 37 . In addition, the strength of FDM parts is significantly influenced by the geometry and degree of internal filling of the part, bed temperature, and printing temperature influencing the fusion of the polymer layers 38 – 40 .…”
Additive manufacturing demonstrates tremendous progress and is expected to play an important role in the creation of construction materials and final products. Contactless (remote) mechanical testing of the materials and 3D printed parts is a critical limitation since the amount of collected data and corresponding structure/strength correlations need to be acquired. In this work, an efficient approach for coupling mechanical tests with thermographic analysis is described. Experiments were performed to find relationships between mechanical and thermographic data. Mechanical tests of 3D-printed samples were carried out on a universal testing machine, and the fixation of thermal changes during testing was performed with a thermal imaging camera. As a proof of concept for the use of machine learning as a method for data analysis, a neural network for fracture prediction was constructed. Analysis of the measured data led to the development of thermographic markers to enhance the thermal properties of the materials. A combination of artificial intelligence with contactless nondestructive thermal analysis opens new opportunities for the remote supervision of materials and constructions.
“…Moreover the fatigue behaviors of the 3D printed samples are discussed in the study. Lee et al [5] investigated the effects of processing parameters on the mechanical properties of fused deposition modelling (FDM)-printed carbon fiber-filled polylactide (CFR-PLA) composites by employing an orthogonal array model. The tensile and impact strengths of the composites are evaluated.…”
Lightweight structures are one of the most studied topics today. Many metal machine elements can be produced from lightweight polymer materials with 3D printer technology. In this study a novel manufacturing method is proposed for the polymer bolts and the effects of the printing directions on the tensile and shear strength are investigated experimentally. Firstly the bolt shafts are produced FDM method by using 3D printer for different print orientations and the final diameters of the bolt shafts are determined by the turning process. A special apparatus is designed and manufacture for threader tool. The screw pitches are opened by using this special apparatus with threader tool. After the manufacturing process, the performance of the produced tensile and shear test samples are defined by using tensile and shear tests. A special tensile test apparatus is also developed in this study. It is seen that the printing orientation has great effects on the tensile and shear durability of the bolts. It has been determined that the strength of the bolts produced with a production angle of 0º is the highest, and the strength of the bolts produced with 45º is the lowest.
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