Build Plate Research Articles

The Influence of Fused Deposition Modeling Parameters on the Properties of PA6/PA66 Composite Specimens by the Taguchi Method and Analysis of Variance.

Fused deposition modeling (FDM) is widely used in the rapid prototyping of polymers. Polyamide (PA) has excellent mechanical properties, but its application in FDM is limited due to its high water absorption, warpage, and forming shrinkage. The material of the filament and the printing parameters of the printer are two critical aspects that affect the performance of a component. The prepared PA6/PA66 (composite polyamide [COPA], PA6:PA66 = 85:15) composite (COPA: acrylonitrile butadiene styrene [ABS]: maleic anhydride grafted acrylonitrile butadiene styrene [ABS-g-MAH]: polyethylene = 800:133:67:100) has low water absorption (0.39%) and high dimensional stability, which has a good application prospect in FDM. The influence of eight FDM parameters, including three rarely reported, on the properties of PA6/PA66 composite specimens was investigated by the Taguchi method. The significance of influencing factors was evaluated by analysis of variance (ANOVA) and the stability by signal-noise ratio. When the layer thickness was 0.15 mm, the infill pattern was zigzags, the build plate adhesion type was brim, and the distance from the nozzle to the printing platform and the layer thickness (ΔL) was 0.05 mm; the specimens' dimensional accuracy, surface quality, and mechanical properties were better than other levels. The layer thickness and infill pattern were the two most important factors. The switch of the cooling fan and the temperature printing platform played a significant role in the specimens' dimensional accuracy and surface quality. ΔL tremendously influenced the thickness and warping degree of the specimens. The preparation of high-performance PA composites and the investigation of multiparameters by the Taguchi method provide a possible solution for applying polyamide in FDM.

Evaluation of computational homogenization methods for the prediction of mechanical properties of additively manufactured metal parts

It is well known that the strongly location-dependent microstructures observed in metal parts made using additive manufacturing (AM) processes differ from those found in components produced via traditional manufacturing processes. This is primarily because the microstructures in AM parts strongly depend on spatially-varying cooling rates that are caused by several factors including part geometry and proximity to the build plate. Consequently, it is necessary to take a fresh look into methods used for calculating resulting mechanical properties, as the increased spatial resolution that must be applied to the description of properties of AM parts calls for vast improvements in computational efficiency. Computational homogenization methods are employed for the calculation of these mechanical properties based on the polycrystalline microstructures typically encountered in metallic materials. Such calculations that enable the description of properties as a function of position increase the accuracy of a vital link in the structure–process–property–performance continuum that falls within the Integrated Computational Materials Engineering (ICME) paradigm. In this work we describe and critically review six of these methods and their application to AM microstructures. We find that the Fast Fourier Transform (FFT) method and the Finite Element Method (FEM) are the optimal choices based on several factors including accuracy, efficiency, and applicability to polycrystalline microstructures. Provided the microstructure is amenable to the use of uniform grids and the assumption of periodic boundary conditions, the FFT method has greater computational efficiency. Where unstructured meshes, adaptive remeshing and/or non-periodic boundary conditions are desired, the FEM is the method of choice. Our recommendations are equally applicable to functionally graded AM parts where site-specific microstructures are engineered using multiple materials or different process parameters. They can also be utilized for other material systems and circumstances where increased accuracy is achieved by describing mechanical properties as a function of location.

Effect of various printing parameters on the accuracy (trueness and precision) of 3D-printed partial denture framework

ObjectivesTo measure and compare the accuracy of 3D-printed materials used for RPD production to improve workflow and eliminate errors in manufacturing. MethodsA partially edentulous maxilla (Kennedy Class III, modification 1) was prepared and designed with proximal plates, rest seats and clasps in one first premolar, one canine and two second molars. A total of 540 3D printed RPD frameworks were 3D printed with three different types of resin (DentaCAST (Asiga, Australia), SuperCAST (Asiga, Australia) and NextDent (3D Systems, Netherlands)). To evaluate the trueness of the printing materials, they were printed with three types of layer thickness: 50 μm, 75 μm and 100 μm, using two types of build angles: 0° and 45° and three types of plate locations: side, middle and corner. After production, all specimens were scanned and superimposed with a control sample that was digitally designed. Using the initial alignment and best-fit alignment method, the root mean square error (RMSE) was calculated. To capture region specific discrepancy, 10 points of XYZ internal discrepancy within RPDs were measured and Euclidean error was calculated. Data was statistically analysed using Shapiro-Wilk and Kruskal-Wallis tests, one-way ANOVA and T-test (SPSS Version 29) and MATLAB (R2022b). ResultsOptimal results were found using 45°, middle of the build plate and layer thicknesses of 100 μm (115 ± 19 μm, DentaCAST), 75 μm (143 ± 14 μm, NextDent), 50 μm (98 ± 35 μm, SuperCAST), which were clinically acceptable. Results were statistically significant when comparing layer thickness in each testing group (p < 0.001). Layer thickness was a primary parameter in the determination of print accuracy among all materials (p < 0.001). Higher discrepancies and failures were observed in 0° prints. No statistically significant difference was found in material usage between build angles or layer thickness (p > 0.005). ConclusionsAll three 3D printing materials exhibited clinically acceptable RMSE results with a build angle of 45° with a printing layer thickness of 50 μm for SuperCAST, 75 μm NextDent and 100 μm for DentaCAST. The highest discrepancies were mostly found in posterior clasps, while the lowest discrepancy was found in palatal straps. Despite unoptimized spacing of prints, frameworks configured to print in the middle of the build plate result in the least printing failures.

Modeling spatial variations in co-axial melt pool monitoring signals in laser powder bed fusion

The transition of additive manufacturing from rapid prototyping to large-scale manufacturing is being impeded by the limited repeatability of part quality within and across independent builds. The property variations are a result of process fluctuations, which can be random or systemic, like the location of the part on the build plate. In-situ sensors are employed to measure these process variations to monitor and control the part properties. A priori estimates of the systemic variations in the in-situ signals can enhance the efficiency of such techniques. In this work, custom builds for IN718, along with multiphysics simulations, are employed to probe systemic trends in the signals from the co-axial melt pool monitoring system on laser powder bed fusion based GE Concept Laser M2. Significant spatial variations are observed in the in-situ melt pool area, and intensity signals, and the subsequent analysis suggests that the interplay of the angled laser beam and the shield gas flow is likely a major source of the spatial trends. Machine learning is employed to develop data-driven surrogate models that make accurate predictions for this systemic variation in the melt pool area and intensity, generalizing across independent builds with significantly diverse print parameters. These models are anticipated to inform control algorithms and tune optimal print parameters with the objective of enhancing the repeatability of the part quality for laser powder bed fusion.

Effect of Printing Parameters on Mechanical Performance of Material-Extrusion 3D-Printed PEEK Specimens at the Point-of-Care

Additive manufacturing (AM) of polyetheretherketone (PEEK) biomaterials using the material-extrusion (MEX) method has been studied for years. Because of the challenging manufacturing process, precisely controlling printing parameters is crucial. This study aimed to investigate the effects of printing parameters such as orientation and position of printing on mechanical properties. Thus, 34 samples were printed using PEEK filament and the MEX process. Samples were divided into two main groups (A,B) according to their printing orientations (A: groups 1–3) and positions on the build plate (B: groups 4–8). Mechanical tensile tests were performed to evaluate the effects of different printing orientations and positions on mechanical properties. The means of the tensile modulus in samples 3D-printed in XY (group 1), XZ (group 2), and ZX (group 3) orientations were not significantly different (p-value = 0.063). Groups 1 and 2 had smaller distributions than group 3 in the means of tensile strength. The t-test showed that the overall means of the measurements in groups 4–8 did not differ significantly (p-value = 0.315). The tensile tests indicated that printing in vertical and horizontal orientations had no significant influence on mechanical properties. There were no significant differences in mechanical strength between top/bottom printed samples in five different lateral positions. Reliability of printing with good mechanical properties could be a step forward to manufacturing patient-specific implants.

The influence of a large build area on the microstructure and mechanical properties of PBF-LB Ti-6Al-4 V alloy

This study investigated the print homogeneity of Ti-6Al-4 V alloy parts, when printed over a large build area of 250 times 250 times 170 mm3, using a production scale laser powder bed additive manufacturing system. The effect of part location across this large build area was investigated based on printed part porosity, microstructure, hardness, and tensile properties. In addition, a Hot Isostatic Pressing (HIP) treatment was carried out on the as-built parts, to evaluate its impact on the material properties. A small increase in part porosity from 0.01 to 0.09%, was observed with increasing distance from the argon gas flow inlet, which was located on one side of the build plate, during printing. This effect, which was found to be independent of height from the build plate, is likely to be associated with enhanced levels of condensate or spatter residue, being deposited at distances, further from the gas flow. Despite small differences in porosity, no significant differences were obtained for microstructural features such as prior β grain, alpha lath thickness, and phase fraction, over the entire build area. Due to this, mechanical performances such as hardness and tensile strengths were also found to be homogenous across the build area. Additionally, it was also observed based on the lattice constants that partial in-situ decomposition of {alpha }^{^{prime}}to alpha +beta phases occurred during printing. Post HIP treatment result showed a decrease of 7 and 6%, in the yield strength (YS) and ultimate tensile strength (UTS), respectively, which was associated with a coarsening of alpha lath widths. The potential of the laser powder bed system for large area printing was successfully demonstrated based on the homogenous microstructure and mechanical properties of the Ti-6Al-4 V alloy parts.

Review on Various Aspects of 3-D Printing in Pharmacy

3D printing also known as additive manufacturing which involves manufacturing of three dimensional objects by layering.3D printing includes layering materials, like plastics, composites or bio-materials to create objects that variety in shape, length, tension and color. This 3D printing generation has intense flexibility in what may be published. 3D printing has the capability to revolutionize the pharmaceutical manufacturing enterprise. Technologies currently being evaluated for use within the 3D printing of prescribed drugs, and the paintings of key market gamers to increase and increase their programs from studies to commercial. Close up of a 3D printing head approximately to begin a print at the printing mattress. The healthcare desires of the populace, and the therapeutics we use to deal with them, are changing. Though generics are undeniably critical, there’s a significant shift towards personalization and customization of remedy – inspired by using the adoption and enhancement of omics technology in healthcare. 3D Printing makes use of software that slices the 3D version into layers (0.01mm thick or less in most cases). Each layer is then traced onto the build plate by the printer, as soon as the pattern is finished, the construct plate is diminished and the subsequent layer is introduced on pinnacle of the previous one. 3D printing generation will revolutionize the pharmaceutical production style and system strategies. However, there's still a enormous barrier to make sure that 3D printed medicines have the same efficacy, protection, and balance as the pharmaceuticals conventionally manufactured by the Pharmaceutical Industry. Regarding the established order of recommendations, laws, first-class systems and protection of use and intake of 3D published drug treatments, it’s miles a top notch assignment for the regulatory authorities entailing great barriers, given the traditional requirements by way of the pharmaceutical sector.

Thermoelectric Printhead Cooler for a Stable Process and Curing Control in RTV-2 Silicone Additive Manufacturing by Direct Ink Writing

The direct additive manufacturing, such as Direct Ink Writing (DIW), of silicone parts holds cost and complexity advantages. However, for extruding strands of low viscosity heat curing silicone rubbers, a build plate temperature of up to 90°C is used, which comes with the challenge of early vulcanization inside the printhead. Thus, this paper presents a thermoelectric cooler for universal printheads. At a build plate temperature of 90°C it prolongates vulcanization by 198.5 % (∆tpot life = 508.8 s), which allows a reduction of print speed for higher quality. Additionally, the influence of external temperature is reduced and the viscosity can be controlled.

Manufacturing of WC-17Co 3D-objects by Laser Powder Bed Fusion followed by heat-treatment

Conventional tungsten carbide (WC) cermet parts containing a cobalt matrix phase are generally produced via powder sintering. In this study it is shown that cermet parts can also be produced by laser powder bed fusion from WC-17Co powder precursor. Optimal process parameters were found for manufacturing without preheated building plate. Micro-structural analysis revealed noteworthy porosity fraction (1.41%) as well as the presence of small-scale cracks in the as-built specimens. It is further shown that most of these defects can be eliminated by heat treatment at ambient pressure or by hot isostatic pressing. Heat treatment also led to the dissolution of the fragile W2C phase. Hardness test results indicate that the performance of the AM parts was comparable to that of a reference produced via powder sintering. The work is a successful demonstration of manufacturing of cermet parts using laser powder bed fusion.

Experimental validation of numerical model for thermomechanical performance of material extrusion additive manufacturing process: Effect of infill design & density

The optimum selection of process parameters, materials, and product design is essential to achieve the desired response of 3D-printed structures, especially in functional components. The current practices of the experimental optimization process require significant resources, which can be limited through numerical modeling and simulation techniques. In this study, a thermomechanical numerical model is used to predict the performance of the additive manufacturing (AM) process, i.e., fused filament fabrication (FFF). 3D printing (3DP) process simulations were performed for tensile testing coupons using carbon fiber-reinforced polyamide-6 (PA6-CF) material. The numerical model predicted the effect of infill patterns and densities on the deflections and distortions during the FFF process. The numerical model predictions were validated via experiments performed under similar conditions. The results conclude that the numerical model can adequately predict the process-induced deflections and distortions during the FFF process. Generally, higher dimensional control was observed for rectangular infill patterns and increased infill density. However, the numerical model overestimates the shrinkage as the stress-relaxation effect is not considered in the numerical model and underestimates the warpages as perfect build plate adhesion is assumed.

Experimental investigation and development of a deep learning framework to predict process-induced surface roughness in additively manufactured aluminum alloys

A deep learning framework is developed to predict the process-induced surface roughness of AlSi10Mg aluminum alloy fabricated using laser powder bed fusion (LPBF). The framework involves the fabrication of round bar AlSi10Mg specimens, surface topography measurement using 3D laser scanning profilometry, extraction, coupling, and streamlining of roughness and LPBF processing data, feature engineering to select the relevant feature set and the development, validation, and evaluation of a deep neural network model. A mix of core and contour-border scanning strategies are employed to fabricate four sets of specimens with different surface roughness conditions. The effects of different scanning strategies, linear energy density (LED), and specimen location on the build plate on the resulting surface roughness are discussed. The inputs to the deep neural network model are the AM process parameters (i.e., laser power, scanning speed, layer thickness, specimen location on the build plate, and the x,y grid location for surface topography measurements), and the output is the surface profile height measurements. The proposed deep learning framework successfully predicts the surface topography and related surface roughness parameters for all printed specimens. The predicted surface roughness ({S}_{a}) measurements are well within 5% of experimental error for the majority of the cases. Moreover, the intensity and location of the surface peaks and valleys as well as their shapes are well predicted, as demonstrated by comparing roughness line scan results with corresponding experimental data. The successful implementation of the current framework encourages further applications of such machine learning-based methods toward AM material development and process optimization.

Features of the impact of hot isostatic pressing and heat treatment on the structure and properties of maraging steel obtained by selective laser melting method

Using the SLM method in a nitrogen blanket with heating to a temperature of 200 °C, samples were obtained at a position of 0° against the build plate. The effect of the hot isostatic pressing (HIP) and heat treatment (HT: hardening + aging) on the structure and mechanical properties of maraging steel CL50 WS was studied (the Russian analogue is ChS4 grade). To analyze the effect of post-processing on the strength characteristics (σb, σ0,2, δ, ψ), tensile tests were conducted. Their results indicated high values of strength and ductility. It has been established that as a result of HT in the steel structure, in addition to α-Fe, γ-Fe, dispersed precipitates of the NiTi3 strengthening phase are formed, the identification of which was carried out by high-resolution transmission electron microscopy. Through the NiTi3 intermetallic phase, the steel has acquired increased tensile strength and yield strength required for the production of critical components and parts for highly loaded turbomachine disks. The change in the porosity of the samples before and after the HIP was analyzed. The microstructure of the samples and the changes that occur under the influence of various post-processing options are studied. The fine-grained homogeneous structure obtained by combining the SLM, HIP and HT provided optimal strength and ductility. Analysis of fractures after mechanical testing showed that the samples after postprocessing are destroyed according to the viscous-pitting mechanism with the formation of a neck.

Effect of print direction on mechanical properties of 3D printed polymer-derived ceramics and their precursors

The use of engineering ceramics with intricate geometries is limited by manufacturing processes and lack ease of machinability of ceramics. Additive manufacturing of pre-ceramic polymers which are pyrolyzed into ceramics after 3D printing has recently been used to circumvent traditional manufacturing processes creating ceramics with complex geometries, however, mechanical characterization is limited. Polymer-derived ceramics and their green-body precursors are printed using digital light projection 3D printing in two orientations (0°- and 90°- to the build plate) and mechanically characterized. The results show that mechanical anisotropy exists both in the green-body polymer samples where the 0°-samples are stronger and stiffer than their 90°-counterparts and the final ceramics, where the stronger samples are fabricated at 90° despite isotropic hardness measurements. Through the manufacturing process, it was noted that samples undergoing pyrolysis built in the 90°-orientation have a pyrolysis survival rate of 94% whereas the 0°-samples showed a survival rate of 54%. The results suggest that the build-direction of 3D printed green-bodies plays a role in both material manufacturing and mechanical integrity of the final ceramic materials.

Extending powder lifetime in additive manufacturing: Chemical etching of stainless steel spatter

• Chemical etching can eliminate most oxides from 316 L spatter. • A reduction in oxide coverage from 7–0.7% was possible. • Removal is thought to occur via initial dissolution of oxide-surrounding metal. • Etched spatter powder performed better in LPBF. • Reduced slag layer, and better wetting was seen for LPBF etched spatter. In laser powder bed fusion, unconsolidated metal powder on the build plate tends to comprise a proportion of oxidised powder after repeated use. This is generally caused by the generation of oxidised spatter particles during processing which can contaminate the powder bed, and be incorporated into future builds, ultimately undermining part integrity. Oxidised metal powder often results in porosity, poor layer-layer bonding and detrimental oxides in the printed part. This work uses a new chemical etching approach to remove oxides from the surface of oxidised stainless steel spatter powder. It was shown that a ten-fold reduction in oxide area coverage on spatter powder was possible through submersion in a solution of heated Ralph's etchant for one hour. Oxide removal is thought to occur mostly via dissolution of the metal surrounding and underneath oxide islands on the powder, allowing more aggressive oxide removal. LPBF processing was performed using spatter, etched and virgin powder sieved to an identical powder size range. Etched spatter showed a reduced oxide slag layer on track surfaces compared to spatter. In addition, incorporation of powder into tracks appeared improved after chemical etching of the powder. This work demonstrates that chemical etching has the potential to be used to increase the re-usability and lifetime of spatter or heavily used powder from widely used and corrosion resistant stainless steel powder.

Build plate conduction cooling for thermal management of wire arc additive manufactured components

Build plate conduction cooling for thermal management of wire arc additive manufactured components

Void Content Measurement of the 3D Printed PEEK Materials by X-Ray Micro Computed Tomography

Additive Manufacturing (AM) is revolutionizing the manufacturing industry as various AM technologies continue to mature and more AM-compatible materials are being developed. Polyether ether ketone (PEEK) is one of the promising materials at the forefront of this technological revolution as efforts to enhance its application as a 3D-printing material are continuously being pursued. In this study, the effect of printing parameters on the void content of 3D-printed PEEK was examined using a non-destructive method, X-ray micro computed tomography (X-ray micro-CT). Of the fused filament fabrication (FFF) parameters considered, higher nozzle temperature and printing speed were seen to promote an increase in void content while higher build plate temperature reduces it. Void content has a direct effect on the mechanical and other properties of the manufactured material and therefore provides a link between the printing parameters and the expected mechanical performance of these materials. This study also highlights the importance of choosing the right printing parameters to ensure the quality of the manufactured PEEK.

Analysis of the Influence of Build Plate Pre-Treatment and Process Parameters on the Bonding of Additively Manufactured Parts of TiAl&lt;sub&gt;6&lt;/sub&gt;V&lt;sub&gt;4&lt;/sub&gt; to the Build Plate

In this paper, the influence of the surface roughness of build plates as well as the process parameters laser power, scan speed and exposure curing time on the bonding of additively manufactured components made of TiAl6V4 to the build plates is analyzed. These analyses are carried out with build plates made of Titanium Grade 2 and AlMgSi0.5. The analyses show that higher surface roughness leads to lower bending strength and thus poorer bonding of components on the build plate. In addition, it is shown that the bending strength normalized to the bonding surface decreases at high laser power, especially at high scanning speeds. Furthermore, multiple exposure results in lower flexural strength.

One-shot additive manufacturing of robotic finger with embedded sensing and actuation

A main challenge in the additive manufacturing (AM) field is the possibility to create structures with embedded actuators and sensors: addressing this requirement would lead to a reduction of manual assembly tasks and product cost, pushing AM technologies into a new dimension for the fabrication of assembly-free smart objects. The main novelty of the present paper is the one shot fabrication of a 3D printed soft finger with an embedded shape memory alloy (SMA) actuator and two different 3D printed sensors (strain gauge and capacitive force sensor). 3D printed structures, fabricated with the proposed approach, can be immediately activated after their removal from the build plate, providing real-time feedback because of the embedded sensing units. Three different materials from two nozzles were extruded to fabricate the passive elements and sensing units of the proposed bioinspired robotic finger and a custom-made Cartesian pick and place robot (CPPR) was employed to integrate the SMA spring actuator into the 3D printed robotic finger during the fabrication processes. Another novelty of the present paper is the direct integration of SMA actuators during the 3D printing process. The low melting thermoplastic polycaprolactone (PCL) was extruded: its printing temperature of 70 °C is lower than the SMA austenitic start temperature, preventing the SMA activation during the manufacturing process. Two different sensors based on the piezoresistive principle and capacitive principle were studied, 3D printed and characterized, showing respectively a sensitivity ratio of change in resistance to finger bending angle to be 674.8 frac{Omega }{^circ mathrm{Angle}} and a capacitance to force ratio of 0.53 frac{mathrm{pF}}{mathrm{N}}. The proposed manufacturing approach paves the way for significant advancement of AM technologies in the field of smart structures with embedded actuators to provide real-time feedback, offering several advantages, especially in the soft robotics domain.

Feedforward control of thermal history in laser powder bed fusion: Toward physics-based optimization of processing parameters

We developed and applied a model-driven feedforward control approach to mitigate thermal-induced flaw formation in laser powder bed fusion (LPBF) additive manufacturing process. The key idea was to avert heat buildup in a LPBF part before it is printed by adapting process parameters layer-by-layer based on insights from a physics-based thermal simulation model. The motivation being to replace cumbersome empirical build-and-test parameter optimization with a physics-guided strategy. The approach consisted of three steps: prediction, analysis, and correction. First, the temperature distribution of a part was predicted rapidly using a graph theory-based computational thermal model. Second, the model-derived thermal trends were analyzed to isolate layers of potential heat buildup. Third, heat buildup in affected layers was corrected before printing by adjusting process parameters optimized through iterative simulations. The effectiveness of the approach was demonstrated experimentally on two separate build plates. In the first build plate, termed fixed processing, ten different nickel alloy 718 parts were produced under constant processing conditions. On a second identical build plate, called controlled processing, the laser power and dwell time for each part was adjusted before printing based on thermal simulations to avoid heat buildup. To validate the thermal model predictions, the surface temperature of each part was tracked with a calibrated infrared thermal camera. Post-process the parts were examined with non-destructive and destructive materials characterization techniques. Compared to fixed processing, parts produced under controlled processing showed superior geometric accuracy and resolution, finer grain size, increased microhardness, and reduced surface roughness.

Investigations of process by-products by means of Schlieren imaging during the powder bed fusion of metals using a laser beam

To produce geometrically complex parts with good mechanical properties, various industries increasingly apply the powder bed fusion of metals using a laser beam. Sufficient control of this laser-based additive manufacturing process is necessary to achieve a reliable development as well as reproducible part properties. Besides adjusting the standard process parameters, such as the laser power or the scanning speed, the process gas is an important parameter that influences the part characteristics. In addition to the inertization of the atmosphere, process by-products can be removed during the manufacturing with a constant gas flow across the build plate. Typically, argon or nitrogen is applied. This study investigated the effects of various argon-helium mixtures in comparison to pure argon gas on the heat balance of process by-products during the processing of a high-strength aluminum alloy by means of Schlieren imaging. The method enables visualizations of the process by-products and is further capable of studying evaporation phenomena. For this purpose, a Schlieren imaging setup was designed and installed in an AconityMINI machine. The experimental results were exploited to validate a simplified heat transfer model introduced in this work. The results indicate that the addition of helium to the process gas lowers the amount of fumes and incandescent spatters and thus could decrease evaporation. Also, it was found that the higher thermal conductivity of helium compared to argon leads to significantly higher cooling of process by-products.