Printing Temperature Research Articles

A study of the effect of printing process parameters on the delamination and surface finish properties of aluminium-infused PLA printed via material extrusion

ABSTRACT Demand for the newer manufacturing techniques to produce materials with difference and specific properties are kept on increasing. The needed specific properties are obtained through composite materials by reinforcing components onto a base material to improve some critical properties. In that way, the polylactic acid (PLA) incorporated with aluminium was used to print the samples through fused filament fabrication (FFF) process. During printing, the printing process parameters have considerable effect on the material properties. At first, specimens are printed as per the Taguchi’s experimental design with L9 Orthogonal array design and the outputs are obtained experimentally. As an extension, this study proposed two neural network-based machine learning models to predict the influence of process parameters like printing temperature (PT), layer height (LH), raster angle (RA) and fill pattern (FP) on the surface finish (SF), surface finish near to the drilled holes (SFNDH), and delamination factor (DF). Both the proposed models recorded the overall prediction accuracy about 99.99%. To ensure the results predicted by the NN models, validation experiments are conducted and compared with the model predicted results. The experimental results are in good agreement with the predicted values which are obtained through numerical modelling.

Additive Manufacturing of an Extended-Release Tablet of Tacrolimus.

An extended-release tablet of tacrolimus as once-daily dosing was fabricated using 3D printing technology. It was developed by combining two 3D-printing methods in parallel. Indeed, an optimized mixture of PVA, sorbitol, and magnesium stearate as a shell compartment was printed through a hot-melt extrusion (HME) nozzle while an HPMC gel mixture of the drug in the core compartment was printed by a pressure-assisted micro-syringe (PAM). A 3D-printed tablet with an infill of 90% was selected as an optimized formula upon the desired dissolution profile, releasing 86% of the drug at 12 h, similar to the commercial one. The weight variation, friability, hardness, assay, and content uniformity determination met USP requirements. A microbial evaluation showed that the 3D-printed tablet does not support microbial growth. SEM analysis showed smooth surfaces with multiple deposited layers. No peak interference appeared based on FTIR analysis. No decomposition of the polymer and drug was observed in the printing temperature, and no change in tacrolimus crystallinity was detected based on TGA and DSC analyses, respectively. The novel, sTable 3D-printed tablet, fabricated using controllable additive manufacturing, can quickly provide tailored dosing with specific kinetic release for personalized medicine at the point-of-care.

Study and Characterization of Polyvinyl Alcohol-Based Formulations for 3D Printlets Obtained via Fused Deposition Modeling.

Three-dimensional (3D) printing has emerged as a new promising technique for the production of personalized dosage forms and medical devices. Polyvinyl alcohol is prominently used as a source material to produce 3D-printed medicines via fused deposition modeling (FDM)-a technology that combines hot melt extrusion and 3D printing. A preliminary screening of three grades of PVA indicated that partially hydrolyzed PVA with a molecular weight (MW) of 31,000-50,000 and plasticized with sorbitol was most suitable for 3D printing. Paracetamol was used as a model drug. The materials and the produced filaments were characterized by X-ray powder diffraction (XRPD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The complex viscosity (η*) of the polymer melts was determined as a function of the angular frequency (ω) at the printing temperature to assess their printability. Three-dimensional printlets with a 40% infill exhibited an immediate release of the API, while tablets with a higher infill were prone to a prolonged release regardless of the filament drug loading. A factorial design was used to give more insight into the influence of the drug-loading of the filaments and the tablet infill as independent variables on the production of 3D printlets. The Pareto chart confirmed that the infill had a statistically significant effect on the dissolution rate after 45 min, which was chosen as the response variable.

Optimization through response surface methodology of 3D printed membrane preparation conditions for use in vanadium redox flow battery: A vanadium/proton selectivity study

AbstractSPEEK membrane applicable in Vanadium Redox Flow Battery (VRFB) have been 3D printed via Fused Deposition Modeling (FDM). Response Surface Methodology (RSM) has been used to optimize conditions for 3D printing membrane. Good membranes characteristics were obtained by manipulating three parameters, namely the printing temperature, the orientation of the printing layer and the sulfonation time. We evaluated the effects of these three variables on the permeability of membranes to protons and vanadium ions. Results have shown that sulfonation is the most significant variable influencing vanadium and proton permeability. The optimal printing conditions were found at 408°C temperature with a horizontal layer orientation, while the best sulfonation is obtained at 6 min. The optimal membrane has an ion exchange capacity of 0.86 mmolg−1, a water uptake ratio of 22%, a VO2+ permeability of 6.1 × 10−8 cm2 min−1, a H+ permeability of 7.0 × 10−6 cm2 min−1, excellent mechanical stability and better H+/VO2+ perm selectivity than conventional sulfonated polyether ether ketone (SPEEK), Fap450 and Nafion211 membranes. The above results show that the 3D‐SPEEK membrane has great advantages and broad prospects for VRFB applications.

Material-Dependent Effect of Common Printing Parameters on Residual Stress and Warpage Deformation in 3D Printing: A Comprehensive Finite Element Analysis Study

Additive manufacturing (AM), commonly known as 3D printing, has gained significant popularity for its ability to produce intricate parts with high precision. However, the presence of residual stresses and warpage deformation are common issues affecting the quality and functionality of 3D-printed parts. This study conducts a comprehensive finite element analysis (FEA) to investigate the material-dependent impact of key printing parameters on residual stress and warpage deformation in 3D printing. The research focuses on three distinct materials: polyetherimide (PEI), acrylonitrile butadiene styrene (ABS), and polyamide 6 (PA6). Various printing parameters are systematically varied, including printing temperature, printing speed, bed temperature, infill density, layer thickness, and infill pattern. The study employs the Taguchi L27 orthogonal array and employs the analysis of variance (ANOVA) statistical technique to assess the significance of the input parameters. The obtained results reveal that certain parameters exhibit a greater sensitivity to material differences, whereas the layer thickness parameter demonstrates a relatively lower sensitivity. Notably, infill density and printing temperature play a crucial role in reducing residual stress for PA6, while the infill pattern parameter proves to be a significant contributor to minimizing warpage deformation across all three materials. These findings underscore the importance of conducting material-specific analyses to optimize 3D printing parameters and achieve the desired quality outcomes while mitigating residual stress and warpage deformation.

Form exploration on different fabrics using material extrusion based additive manufacturing and end users experience

The additive manufacturing (AM) of customized wearable/embroidery products has been investigated by previous research in a variety of applications. But hitherto, fewer studies have investigated the design customization, post-processing (in terms of washing and iron press test) of embroidery, surface properties, and critical user experience. This study aims to investigate the quality features of customized embroidery produced through 3D printing and presents the roadmap of concept to market in the textile industry. This study analyzed the quality features of customized embroidery made on three different fabric materials (polyester, cotton, and satin) through material extrusion-based 3D printing technology. The best results were achieved when printing embroideries on satin fabric with a layer thickness of 0.06 mm and a printing temperature of 230 °C. Based upon the investigations, varying the nozzle temperature and type of fabrics have significantly affected the surface properties of the embroidery. The washing and hot pressing do not affect the quality of the embroidery in terms of surface and adhesion properties. Additionally, a user survey of 20 participants favored embroideries on polyester fabric printed with a layer thickness of 0.18 mm and a printing temperature of 250 °C.

Influence of printing-based factors on the mechanical properties of hexagonal lattice-structured 3D printed novel walnut shell/polylactic acid composite

The incorporation of bio-based natural fillers and lattice structures in thermoplastic polymer has superior advantages such as a reduction in the usage of conventional polymers with improved damping and mechanical properties. The present work focuses on the development of Walnut Shell/PLA (WSP) lattice-structured composite by the Fused Filament Fabrication technique. The flexural strength, compression strength, and thickness error properties of the hexagon lattice-structured WSP composites are optimized by varying Printing-Based Factors (PBFs) which include infill density (60%, 80%, and 100%), nozzle temperature (190°C, 210°C, and 230°C), printing speed (10 mm/sec, 20 mm/sec, and 30 mm/sec), and layer height (0.1 mm, .2 mm, and .3 mm). The flexural and compression test experiments were conducted as per the ASTM D790 and ASTM D695 standards. The process optimization of the measured responses is made by using Taguchi grey relational grade optimization technique. The experimental outcomes such as compressive and flexural strength and minimal dimensional error are converted into the Grey Relational Grade (GRG) for the optimization process. The results show that the Signal-to-Noise ratio (S/N) from the measured GRG clearly shows that, the lower layer height of 0.1 mm, higher nozzle temperature of 230°C, higher infill density of 100%, and average printing speed of 20 mm/sec is an optimal experimental condition for attaining higher strengths and lower errors. From the Analysis of Variance (ANOVA) analysis, the printing temperature, and layer height are the most persuasive PBFs for the mechanical and physical characteristics with respect to the incorporated lattice structure. The optimized experimental conditions develop maximum flexural and compressive strengths of 4.98 MPa and 28.19 MPa, in addition to a lower thickness error of .186 mm obtained for hexagon lattice-structured WSP biopolymeric composites.

Rheological and mechanical assessment for formulating hybrid feedstock to be used in MIM & FFF

Processes involving additive manufacturing (AM) and Powder Injection Moulding (PIM) in industry show great potential in producing parts with complex shapes, covering both short series of customed components and high production volumes. A deep study into the fundamentals of the material flow behaviour according to both processing methods requirements, not previously described, is carried out and the synergy of PIM and AM based on Fused Filament Fabrication (FFF) is confirmed. The significance of having a robust material, defined as “hybrid feedstock”, carefully designed to enable the FFF and PIM process, including the debinding and sintering stages, is discussed. The mechanical properties of the 17-4 PH filaments, such as shear strength and maximum force, are analysed, and it is concluded that the choice of an appropriate binder system is crucial for achievement optimal performance during the printing process. The rheological properties of the materials (fluidity and shear thinning behaviour) are also examined and the importance of considering printing speed and temperature to control nozzle pressure and ensure successful printing is emphasized. Furthermore, the mechanical properties of the filaments with different metallic powder loadings are discussed, The need to stablish limits for material suitability in terms of shear stress and activation energy is also mentioned. Overall, the scientific discussion addresses various relevant aspects related to the mechanical and rheological properties of the materials used in 3D printing of metals using FFF technology. Conclusions based on experimental results are provided and key parameters to consider for successful printed parts are highlighted.

Post-Ultraviolet-Curing Process Effects on Low-Velocity Impact Response of 3D Printed Polylactic Acid Parts

In this study, polylactic acid (PLA) parts produced with the 3D fused deposition modelling (FDM) technique were cured with ultraviolet irradiation (post-UV-curing) after production, and the low-velocity impact behaviour of the parts was experimentally investigated. Accordingly, PLA parts were subjected to post-UV-curing at 15-, 30-, 45-, and 60-minute periods. The impact behaviour of the specimens produced with production parameters of 200 °C printing temperature, 0.2 mm layer thickness, 50 mm/s printing speed, 100% infill rate, and 45° raster angle was compared with the raw specimens after the post-UV-curing process was applied. As a result of the impact tests, peak force, peak displacement, peak energy, and puncture energy values were obtained from the force-displacement graphs. It has been revealed that the post-UV-curing implementation increases the peak force values of PLA specimens and decreases the displacement values compared to the raw specimens. All specimens' impact behaviour improves with the post-UV-curing process; however, a decreasing trend is entered after 30 min.

Digitizing protocols into single reactors for the one-pot synthesis of nanomaterials

Digitizing protocols into single reactors for the one-pot synthesis of nanomaterials

3D polymer composite filament development from post‐consumer polypropylene and disposable chopstick fillers

AbstractThis study focused on the development of three‐dimensional (3D) polymer composite filament made of disposable chopstick (DC) and post‐consumer polypropylene (PPP). The PPP/DC composite parts were printed via fused filament fabrication (FFF) process. The effect of the printing temperature and different DC fiber content on the properties of the 3D printed parts were investigated. The printing temperature of 200–220°C was suitable for these filaments because the printing temperature did not show any thermal degradation, as proven by thermogravimetric analysis. Furthermore, the thermal stability of the 3D filament increased with DC content. The chemical modification with sodium hydroxide (NaOH) was carried out on DC to remove the unwanted organic components by showing changes in peak intensity in the Fourier transform infrared analysis. Moreover, the melt flow index of the composite filaments decreased with increasing of the DC content and caused the composites' viscosity increased. The results show that the optimum printing temperature of 210°C would reduce the warping and gave better tensile properties to the 3D printed parts. Nevertheless, the tensile strength and elongation at break of the 3D printed PPP/DC parts reduced as the DC content increased because the presence of some air gap and fiber pull out on the fracture surface of 3D printed parts, which are in line with the results observed from scanning electron microscopy. However, the tensile strength and elongation at break percentage of all 3D printed PPP/DC composite parts were higher in comparison with the 3D parts printed by commercial wood plastic composite filament.

Investigating impacts of FDM printing parameters and geometrical features on void formation in 3D printed automotive components

Additive manufacturing (AM) has opened a world of new possibilities in the automotive industry by offering high flexibility in design, shortening production time, and producing lightweight and customizable parts. Despite these advantages, the high risk of defect formation associated with AM processes and the difficulty of defect detection in quality control stages have hindered the rapid adoption of AM in the automotive industry. Mechanical tests are destructive tests which are usually used for quality control of conventionally fabricated components. However, they are not practical for quality control of AM parts since, due to the higher risk of defects, a higher number of AM parts should be mechanically tested which is time-consuming and expensive. Hence, rather than destructive mechanical tests, automakers require non-destructive imaging techniques for AM parts to characterize defects for a high number of samples at the quality control stage. This study aims to examine the impact of printing parameters and geometrical features on the void formation of an automotive component (car window holder). These outcomes will be helpful in the establishment of non-invasive quality control for the window car holder which is based on imaging techniques. For this purpose, a window car holder was printed with varying printing parameters using the FDM technique. Based on the geometry of the component, two regions with distinct geometrical features were specified and analyzed using Micro-CT. Results indicate that by increasing printing speed (30 to 60 mm/min) and temperature (230 °C to 250 °C), voids fraction decreased. Conversely, when increasing the printing layer thickness (0.1 to 0.3 mm), the void fraction increased. It was also concluded that void formation in regions with curved surfaces and overhang structures is significantly higher compared to edges with an angle of 90 ° to 60 °. These results offer a platform to reduce the risk of defect formation in 3D-printed automotive parts, improving quality control.

Towards point-of-care manufacturing and analysis of immediate-release 3D printed hydrocortisone tablets for the treatment of congenital adrenal hyperplasia

Hydrocortisone (HC) is the preferred drug in children with congenital adrenal hyperplasia due to its lower potency as well as fewer reports of side effects. Fused deposition modelling (FDM) 3D printing holds the potential to produce low-cost personalised doses for children at the point of care. However, the compatibility of the thermal process to produce immediate-release bespoke tablets for this thermally labile active is yet to be established. This work aims to develop immediate-release HC tablets using FDM 3D printing and assess drug contents as a critical quality attribute (CQA) using a compact, low-cost near-infrared (NIR) spectroscopy as a process analytical technology (PAT). The FDM 3D printing temperature (140 °C) and drug concentration in the filament (10%-15% w/w) were critical parameters to meet the compendial criteria for drug contents and impurities. Using a compact low-cost NIR spectral device over a wavelength of 900–1700 nm, the drug contents of 3D printed tablets were assessed. Partial least squares (PLS) regression was used to develop individual calibration models to detect HC content in 3D printed tablets of lower drug contents, small caplet design, and relatively complex formula. The models demonstrated the ability to predict HC concentrations over a wide concentration range (0–15% w/w), which was confirmed by HPLC as a reference method. Ultimately, the capability of the NIR model had preceding dose verification performance on HC tablets, with linearity (R2 = 0.981) and accuracy (RMSECV = 0.46%). In the future, the integration of 3DP technology with non-destructive PAT techniques will accelerate the adoption of on-demand, individualised dosing in a clinical setting.

Poly(3-hydroxybutyrate) (PHB) and Polycaprolactone (PCL) Based Blends for Tissue Engineering and Bone Medical Applications Processed by FDM 3D Printing.

In the presented work, poly(3-hydroxybutyrate)-PHB-based composite blends for bone medical applications and tissue engineering are prepared and characterized. PHB used for the work was in two cases commercial and, in one case, was extracted by the chloroform-free route. PHB was then blended with poly(lactic acid) (PLA) or polycaprolactone (PCL) and plasticized by oligomeric adipate ester (Syncroflex, SN). Tricalcium phosphate (TCP) particles were used as a bioactive filler. Prepared polymer blends were processed into the form of 3D printing filaments. The samples for all the tests performed were prepared by FDM 3D printing or compression molding. Differential scanning calorimetry was conducted to evaluate the thermal properties, followed by optimization of printing temperature by temperature tower test and determination of warping coefficient. Tensile test, three-point flexural test, and compression test were performed to study the mechanical properties of materials. Optical contact angle measurement was conducted to determine the surface properties of these blends and their influence on cell adhesion. Cytotoxicity measurement of prepared blends was conducted to find out whether the prepared materials were non-cytotoxic. The best temperatures for 3D printing were 195/190, 195/175, and 195/165 °C for PHB-soap/PLA-SN, PHB/PCL-SN, and PHB/PCL-SN-TCP, respectively. Their mechanical properties (strengths ~40 MPa, moduli ~2.5 GPa) were comparable with human trabecular bone. The calculated surface energies of all blends were ~40 mN/m. Unfortunately, only two out of three materials were proven to be non-cytotoxic (both PHB/PCL blends).

Effects of printing parameters on 4D-printed PLA actuators

Controlling the printing parameters of four-dimensional (4D) printed actuators can be used to set the internal strain of the actuators. This approach can be utilised when using the fused deposition modelling method to develop 4D-printed actuators, allowing non-manual shape programming. However, there is a lack of comprehensive studies that investigate the effects of printing parameters on the actuation performance of 4D-printed actuators. In this study, the effects of four printing parameters on the bending angle of 4D-printed polylactic acid (PLA) actuators are reported. These printing parameters include the printing speed, printing temperature, ratio of passive-to-active layers, and layer height. In addition, these printing parameters are investigated while changing the height of the actuators. The results show that increasing the printing speed increases the internal strain while increasing the printing temperature, layer height, or actuator height has the opposite effect. Moreover, it is found that a ratio of passive-to-active layers of 50% maximises the strain while selecting a higher or lower ratio causes the opposite effect. Based on the results, four mathematical predictive models are developed to determine the bending angle induced in the actuators when printed based on each printing parameter. Then, a predictive model that relates all the printing parameters and actuator height to the bending angle is developed. The predictive model is based on the characterization results of 534 PLA actuators, providing an R-squared value of 0.98. Then, a finite element analysis model is developed to replicate the shape memory effect in actuators. To prove the accuracy of the proposed concept, two grippers with four and eight fingers are developed. The results show that the printing parameters can be used to control the bending angle of each finger based on the design specifications.

Multiple-State Nonvolatile Memory Based on Ultrathin Indium Oxide Film via Liquid Metal Printing.

In this work, the ultrathin two-dimensional (2D) indium oxide (InOx) with a large area of more than 100 μm2 and a high degree of uniformity was automatically peeled off from indium by the liquid-metal printing technique. Raman and optical measurements revealed that 2D-InOx has a polycrystalline cubic structure. By altering the printing temperature which affects the crystallinity of 2D-InOx, the mechanism of the existence and disappearance of memristive characteristics was established. The tunable characteristics of the 2D-InOx memristor with reproducible one-order switching was manifest from the electrical measurements. Further adjustable multistate characteristics of the 2D-InOx memristor and its resistance switching mechanism were evaluated. A detailed examination of the memristive process demonstrated the Ca2+ mimic dynamic in 2D-InOx memristors as well as the fundamental principles underlying biological and artificial synapses. These surveys allow us to comprehend a 2D-InOx memristor using the liquid-metal printing technique and could be applied to future neuromorphic applications and in the field of revolutionary 2D material exploration.

Optimization of 3D Printing Parameters of Polylactic-Co-Glycolic Acid-Based Biodegradable Antibacterial Materials Using Fused Deposition Modeling.

A high incidence of ureteral diseases was needed to find better treatments such as implanting ureteral stents. The existing ureteral stents produced a series of complications such as bacterial infection and biofilm after implantation. The fused deposition modeling (FDM) of 3D printing biodegradable antibacterial ureteral stents had gradually become the trend of clinical treatment. But it was necessary to optimize the FDM 3D printing parameters of biodegradable bacteriostatic materials to improve the precision and performance of manufacturing. In this study, polylactic-co-glycolic acid (PLGA), polycaprolactone (PCL), and nanosilver (AgNP) were mixed by the physical blending method, and the 3D printing parameters and properties were studied. The relationship between printing parameters and printing errors was obtained by single-factor variable method and linear fitting. The performance of 3D printing samples was obtained through infrared spectrum detection, molecular weight detection, and mechanical testing. The printing temperature and the printing pressure were proportional to the printing error, and the printing speed was inversely proportional to the printing error. The 3D printing has little effect on the functional groups and molecular weights of biodegradable antibacterial materials. The addition of AgNP increases the compressive strength and breaking strength by 8.332% and 37.726%, which provided ideas for regulating the mechanical properties. The parameter range of biodegradable bacteriostatic materials for thermal melting 3D printing was precisely established by optimizing the parameters of printing temperature, printing pressure, and printing speed, which would be further applied to the advanced manufacturing of biodegradable implant interventional medical devices.

Preparation of pre-impregnated continuous carbon fiber reinforced nylon6 filaments and the mechanical properties of 3D printed composites

The addition of continuous fibers as the reinforcement is considered to be an effective option to promote the mechanical properties of 3D printed parts. In this paper, different types of prepreg continuous fiber filaments for 3D printing were prepared, and the effects of fiber types and content on the tensile strength of filaments were investigated. Moreover, the prepared filaments were also applied to 3D printing continuous fiber reinforced composite parts. The effects of the infiltration degree on the properties and its strengthening mechanism were studies by failure morphologies. The results showed that the strength of filament was influenced by both internal infiltration degree and resin content, at the same fiber content, the tensile modulus of the filament increases with resin content, and the maximum tensile force can reach 0.21 MPa (3k-0.68). The tensile strength of the sample is negatively correlated with the fiber content in the filament, while the shear strength is positively correlated with the fiber content. At the printing temperature of 280 °C, the printed samples show better tensile and shear properties of 189 MPa and 29 MPa, respectively.

Achieving effective interlayer bonding of PLA parts during the material extrusion process with enhanced mechanical properties

The additive manufacturing technique of material extrusion has challenge of excessive process defects and not achieving the desired mechanical properties. The industry is trying to develop certification to better control variations in mechanical attributes. The current study is a progress towards understanding the evolution of processing defects and the correlation of mechanical behavior with the process parameters. Modeling of the 3D printing process parameters such as layer thickness, printing speed, and printing temperature is carried out through L27 orthogonal array using Taguchi approach. In addition, CRITIC embedded WASPAS is adopted to optimize the parts' mechanical attributes and overcome the defects. Flexural and tensile poly-lactic acid specimens are printed according to ASTM standards D790 and D638, respectively, and thoroughly analyzed based on the surface morphological analysis to characterize defects. The parametric significance analysis is carried out to explore process science where the layer thickness, print speed, and temperature significantly control the quality and strength of the parts. Mathematical optimization results based on composite desirability show that layer thickness of 0.1 mm, printing speed of 60 mm/s, and printing temperature of 200 °C produce significantly desirable results. The validation experiments yielded the maximum flexural strength of 78.52 MPa, the maximum ultimate tensile strength of 45.52 MPa, and maximum impact strength of 6.21 kJ/m2. It is established that multiple fused layers restricted the propagation of cracks with minimum thickness due to enhanced diffusion between the layers.

Experimental study of wax-material support structure for fused deposition modeling printed parts with overhanging sections

Additive manufacturing of PLA parts using wax-based filament as a support structure was investigated by implementing the 2-level 3-factors full factorial design of experiments (DoE). The aim of the experiments was to identify significant FDM factors that affect the surface roughness of the parent part in the PLA/Wax interfacial region. In addition, the important factors influencing bonding strength between PLA and wax were identified using the same full factorial DoE. The printing parameters chosen for the analysis are printing temperature, nozzle speed, and the pattern type at the interfacial area. The findings of the study show that the wax-based filament can be effectively used as support material with the condition that the PLA printing temperature is at its lowest value and the nozzle speed is close to 40 mm/s. With the optimal printing condition, the surface roughness value (Ra) can reach as low as 18 μm value and the bonding strength of 0.27 MPa at the interfacial area. The results of the study have revealed the capability of FDM technology to join materials having considerably dissimilar properties.