scholarly journals A QbD Approach for Evaluating the Effect of Selective Laser Sintering Parameters on Printability and Properties of Solid Oral Forms

Pharmaceutics ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1701
Author(s):  
Yanis A. Gueche ◽  
Noelia M. Sanchez-Ballester ◽  
Bernard Bataille ◽  
Adrien Aubert ◽  
Jean-Christophe Rossi ◽  
...  
Keyword(s):  
Energy Density ◽  
Drug Release ◽  
Layer Thickness ◽  
Process Parameters ◽  
Laser Power ◽  
Heating Temperature ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Disintegration Time ◽  
Scan Speed

The aim of this work was to investigate the effect of process parameters on the printability of a formulation containing copovidone and paracetamol, and on the properties of solid oral forms 3D-printed through selective laser sintering. Firstly, the influence of the heating temperature was evaluated individually, and it was revealed that this parameter was critical for printability, as a sufficiently high temperature (100 °C) is necessary to avoid curling. Secondly, the effects of laser power, scan speed, and layer thickness were determined using a Box–Behnken design. The measured responses, printing yield, height, weight, hardness, disintegration time, and percentage of drug release at 10 min showed the following ranges of values: 55.6–100%, 2.92–3.96 mm, 98.2–187.2 mg, 9.2–83.4 N, 9.7–997.7 s, and 25.8–99.9%, respectively. Analysis of variance (ANOVA) proved that the generated quadratic models and the effect of the three–process parameters were significant (p < 0.05). Yield improved at high laser power, low scan speed, and increased layer thickness. Height was proportional to laser power, and inversely proportional to scan speed and layer thickness. Variations in the other responses were related to the porosity of the SOFs, which were dependent on the value of energy density. Low laser power, fast scan speed, and high layer thickness values favored a lower energy density, resulting in low weight and hardness, rapid disintegration, and a high percentage of drug release at 10 min. Finally, an optimization was performed, and an additional experiment validated the model. In conclusion, by applying a Quality by Design approach, this study demonstrates that process parameters are critical for printability, but also offer a way to personalize the properties of the SOFs.

The Optimization Design Study of Selective Laser Sintering Process Parameters on the Pro-Coated Sand Mold

2011 ◽  
Vol 55-57 ◽  
pp. 853-858
Author(s):  
Rong Cheng ◽  
Xiao Yu Wu ◽  
Jian Ping Zheng
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Dimensional Accuracy ◽  
Processing Parameters ◽  
Laser Sintering ◽  
Process Variables ◽  
Scan Speed ◽  
Coated Sand

This paper presents experimental investigations on influence of important process parameters viz., laser power, scan speed, layer thickness, hatching space along with their interactions on dimensional accuracy of Selective Laser Sintering (SLS) processed pro-coated sand mold. It is observed that dimensional error is dominant along length and width direction of built mold. Optimum parameters setting to minimize percentage change in length and width of standard test specimen have been found out using Taguchi’s parameter design. Optimum process conditions are obtained by analysis of variance (ANOVA) is used to understand the significance of process variables affecting dimension accuracy. Scan speed and hatching space are found to be most significant process variables influencing the dimension accuracy in length and width. And laser power and layer thickness are less influence on the dimension accuracy. The optimum processing parameters are attained in this paper: laser power 11 W; scan speed 1200 mm/s; layer thickness 0.5 mm and hatching space 0.25 mm. It has been shown that, on average, the dimensional accuracy under this processing parameters combination could be improved by approximately up to 25% compared to other processing parameters combinations.

Research on Warpage of Polystyrene in Selective Laser Sintering

2010 ◽  
Vol 43 ◽  
pp. 578-582 ◽  
Author(s):  
C.Y. Wang ◽  
Q. Dong ◽  
X.X. Shen
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Main Process ◽  
Influence Of Process Parameters ◽  
Temperature Changes ◽  
Hatch Spacing

Warpage is a crucial factor to accuracy of sintering part in selective laser sintering (SLS) process. In this paper, The influence of process parameters on warpage when sintering polystyrene(PS) materials in SLS are investigated. The laser power, scanning speed, hatch spacing, layer thickness as well as temperature of powder are considered as the main process parameters. The results showed that warpage increases with the increase of hatch space. Contary to it, warpage decreases with the increase of laser power. Warpage decreases with the increase of layer thickness between 0.16~0.18mm and changes little with increase of the thickness. Warpage increases along with the increase of scanning speed but decreases when the speed is over about 2000mm/s. When the temperature changes between 82°C-86°C, warpage decreases little with the increase of temperature. But further increase of temperature leads to warpage decreasing sharply when the temperature changes between 86°C-90°C.

Effect of processing parameters on dimensional accuracy and bending strength of graphite flake/phenolic resin powder mixture in SLS process

2019 ◽  
Vol 233 (13) ◽  
pp. 4497-4507 ◽  
Author(s):  
Haihua Wu ◽  
Yu Sun ◽  
Jianhui Peng ◽  
Caihua Huang ◽  
Xicong Ye
Keyword(s):  
Energy Density ◽  
Layer Thickness ◽  
Laser Power ◽  
Phenolic Resin ◽  
Bending Strength ◽  
Dimensional Accuracy ◽  
Axial Direction ◽  
Process Variable ◽  
Graphite Flake ◽  
Scan Speed

Graphite flake/phenolic resin powder mixture had been prepared via selective laser sintering process. A dimensional analysis involving radial and axial deviation was performed, and the effect of SLS process parameters (laser power, scan spacing, scan speed, layer thickness) in both radial and axial directions were investigated. Laser power is found to be the most significant process variable in radial dimensional accuracy, while in axial direction layer thickness and laser power are the most significant process variable by range analysis based on orthogonal experiment. The optimum combination of parameters in graphite flake/phenolic resin powders mixture SLS process for high dimensional accuracy in radial direction was laser power, scan speed, scan spacing, and layer thickness of 20 W, 1500 m/s, 0.1 mm, and 0.1 mm, respectively, while the optimum combination of parameters in axial direction was laser power, scan speed, scan spacing, and layer thickness of 20 W, 2000 mm/s, 0.1 mm, and 0.15 mm, respectively. Energy density was introduced to better incorporate the processing parameters with dimensional accuracy and mechanical properties, and both dimensional accuracy and bending strength were analyzed under varying energy density and layer thickness, and results showed that in the range of energy density of 0.075–0.15 J/mm2, layer thickness of 0.1–0.2 mm, a graphite flake/phenolic resin laser sintered part with appropriate bending strength and dimensional accuracy could be prepared.

scholarly journals Selective Laser Sintering of PA6: Effect of Powder Recoating on Fibre Orientation

2020 ◽  
Vol 4 (3) ◽  
pp. 108
Author(s):  
Tobias Heckner ◽  
Michael Seitz ◽  
Sven Robert Raisch ◽  
Gerrit Huelder ◽  
Peter Middendorf
Keyword(s):  
Computed Tomography ◽  
Mechanical Properties ◽  
Layer Thickness ◽  
Laser Power ◽  
Laser Energy ◽  
Fibre Orientation ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Shear Stresses ◽  
Imaging Results

In Selective Laser Sintering, fibres are strongly orientated during the powder recoating process. This effect leads to an additional increase of anisotropy in the final printed parts. This study investigates the influence of process parameter variation on the mechanical properties and the fibre orientation. A full factorial design of experiment was created to evaluate the processing parameters of recoating speed, layer thickness and laser power on the part’s modulus of elasticity. Based on the mechanical testing, computed tomography was applied to selected samples to investigate the process-induced fibre microstructure, and calculate the fibre orientation tensors. The results show increasing part stiffness in the deposition direction, with decreasing layer thickness and increasing laser power, while the recoating speed only shows little effect on the mechanical performance. This complies with computed tomography imaging results, which show an increase in fibre orientation with smaller layer thickness. With thinner layers, and hence smaller shear gaps, shear stresses induced by the roller during recoating increase significantly, leading to excessive fibre reorientation and alignment. The high level of fibre alignment implies an increase of strength and stiffness in the recoating direction. In addition, thinner layer thickness under constant laser energy density results in improved melting behaviour, and thus improved fibre consolidation, consequently further increasing the mechanical properties. Meanwhile, the parameters of recoating speed and laser power do not have a significant impact on fibre orientation within their applicable process windows.

Influence of Selective Laser Melting Process Parameters on Densification Behavior, Surface Quality and Hardness of 18Ni300 Steel

2020 ◽  
Vol 861 ◽  
pp. 77-82
Author(s):  
Gan Li ◽  
Cheng Guo ◽  
Wen Feng Guo ◽  
Hong Xing Lu ◽  
Lin Ju Wen ◽  
...  
Keyword(s):  
Energy Density ◽  
Relative Density ◽  
Maraging Steel ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Laser Power ◽  
Densification Behavior ◽  
Laser Melting ◽  
Scan Speed

This study investigated the effect of laser power (P), scan speed (v) and hatch space (h) on densification behavior, surface quality and hardness of 18Ni300 maraging steel fabricated by selective laser melting (SLM). The results indicated that the relative density of the SLMed samples has a shape increase from 73% to 97% with the laser energy density increasing from 0.5 to 2.2 J/mm2. The relative density ≥ 99% was achieved at the energy density in the range of 2.2~5.9 J/mm2. The optimum process parameters were found to be laser power of 150~200 W, scan speed of 600mm/s and hatch space of 0.105mm. In addition, it was found that the hardness increased initially with the increasing relative density up to relative density of 90% and then little relationship, but finally increase again significantly. This work provides reference for determining process parameters for SLMed maraging steel and the development of 3D printing of die steels.

Experimental Study on Warping Height of PA12/HDPE Specimen by Selective Laser Sintering

2010 ◽  
Vol 43 ◽  
pp. 430-433
Author(s):  
Nai Fei Ren ◽  
Pan Wang ◽  
Yan Luo ◽  
Hui Juan Wu
Keyword(s):  
Process Parameters ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Sintering Process ◽  
Influence Of Process Parameters ◽  
Optimum Parameters ◽  
Scan Speed ◽  
The Relationship

The dimensional accuracy and mechanics properties of parts made by Selective Laser Sintering depend greatly on the sintering process parameters. The influence of process parameters on warping weight of parts sintered by blends of polyamide (PA12) and high density polyethylene (HDPE) was studied. The relationship between the process parameters and the warping height was presented. The surface morphology of the part and uniformity of powder mixed were analyzed by SEM. The optimum parameters of minimum warping height were obtained: preheat temperature 110°C, scan speed 300mm/s, laser power 21W, thickness of single layer 0.2mm.

Selective Laser Sintering and Subsequent Gas Nitrocarburizing of Low Carbon Steel Powder

2008 ◽  
Vol 2 (3) ◽  
pp. 168-174 ◽  
Author(s):  
Takayuki Nakamoto ◽  
◽  
Nobuhiko Shirakawa ◽  
Yoshio Miyata ◽  
Takumi Sone ◽  
...  
Keyword(s):  
Energy Density ◽  
Volume Fraction ◽  
Selective Laser Sintering ◽  
Low Carbon Steel ◽  
Steel Powder ◽  
Laser Sintering ◽  
Low Carbon ◽  
Optimum Conditions ◽  
Scan Speed ◽  
Very High

Optimum conditions for laser irradiation to achieve fully dense SLS (Selective Laser Sintering) specimens have been investigated for S15C steel, in order to check the industrial feasibility of the SLS process. The mechanical properties of SLS processed S15C steel as well as the surface hardenability have also been investigated. The volume fraction of pores in S15C steel decreases as the scan speed, scan spacing and layer thickness decrease and as the laser power increases, so that the density of SLS specimens increases as the energy density increases. The specimens sintered at an energy density of 800 J/mm3 exhibit very low porosity and, hence, very high density, comparable to those of the corresponding wrought material. Complete elimination of pores is indispensable for the ductility and strength of SLS specimens. Excellent wear resistance can be provided with the surface of S15C steel produced by the SLS process by gas nitrocarburizing because of the formation of Fe2-3N nitride with a very high value of microhardness on the surface.

Optimization of parameters for SLS of WC-Co

2017 ◽  
Vol 23 (6) ◽  
pp. 1202-1211 ◽  
Author(s):  
Sanjay Kumar ◽  
Aleksander Czekanski
Keyword(s):  
Energy Density ◽  
Process Parameters ◽  
Laser Power ◽  
Laser Energy ◽  
Beam Diameter ◽  
Content Type ◽  
Powder Bed ◽  
Scan Speed ◽  
New Equation ◽  
Hatch Spacing

Purpose WC-Co is a well-known material for conventional tooling but is not yet commercially available for additive manufacturing. Processing it by selective laser sintering (SLS) will pave the way for its commercialization and adoption. Design/methodology/approach It is intended to optimize process parameters (laser power, hatch spacing, scan speed) by fabricating a bigger part (minimum size of 10 mm diameter and 5 mm height). Microstructural analysis, EDX and hardness testing is used to study effects of process parameters. Optimized parameter is ascertained after fabricating 49 samples in preliminary experiment, 27 samples in pre-final experiment and 9 samples in final experiment. Findings Higher laser power gives rise to cracks and depletion of cobalt while higher scan speed increases porosity. Higher hatch spacing is responsible for delamination and displacement of parts. Optimized parameters are 270 W laser power, 500 mm/s scan speed, 0.04 mm layer thickness, 0.04 mm hatch spacing (resulting in energy density of 216 J/mm3) and 200°C powder bed temperature. A part comprising of small hole of 2 mm diameter, thin cylindrical pin of 0.5 mm diameter and thin wall of 2 mm width bent up to 30° angle to the base plate is fabricated. In order to calculate laser energy density, a new equation is introduced which takes into account both beam diameter and hatch spacing unlike old equation does. In order to calculate laser energy density, a new equation is formulated which takes into account both beam diameter and hatch spacing unlike old equation does. WC was not completely melted as intended giving rise to partial melting-type binding mechanism. This justified the name SLS for process in place of SLM (Selective Laser Melting). Research limitations/implications Using all possible combination of parameters plus heating the part bed to maximum shows limitation of state-of-the-art commercial powder bed fusion machine for shaping hardmetal consisting of high amount of WC (83 wt. per cent). Practical implications The research shows that microfeatures could be fabricated using WC-Co which will herald renewed interest in investigating hardmetals using SLS for manufacturing complex hard tools, molds and wear-resistance parts. Originality/value This is the first time micro features are successfully fabricated using WC-Co without post-processing (infiltration, machining) and without the help of additional binding material (such as Cu, Ni, Fe).

Direct Selective Laser Sintering of WC-Co Cemented Carbide by Premixing of Additives

2012 ◽  
Author(s):  
Hideki Kyogoku ◽  
Takeshi Uemori ◽  
Akihiko Ikuta ◽  
Kenichi Yoshikawa ◽  
Hitoshi Ohmori
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Smooth Surface ◽  
Laser Scanning ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Cemented Carbides ◽  
Sintering Process ◽  
Laser Melting ◽  
Scan Speed

In this study, the fabrication conditions of WC cemented carbides by direct selective laser melting were investigated. The effects of additives, such as Co, Cu-20%Sn and Cu powders, and laser scanning conditions on laser sintering process were examined to fabricate a sound laser-scanned body of WC cemented carbides. The optimum laser power, scan speed and scan pitch were found out by experiments. It was found that the continuously smooth single-scan track can be obtained at a lower laser power and a higher scan speed by the addition of 30% Cu powder. The smooth surface of the laser-scanned body could be fabricated at a laser power of 9 W, a scan speed of 20 mm/s and a scan pitch of 0.05 mm.

scholarly journals Effects of various processing parameters on the mechanical properties of sisal fiber/PES composites produced via selective laser sintering

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5710-5724
Author(s):  
Aboubaker I. B. Idriss ◽  
Jian Li ◽  
Yangwei Wang ◽  
Yanling Guo ◽  
Elkhawad A. Elfaki
Keyword(s):  
Mechanical Strength ◽  
Laser Power ◽  
Low Cost ◽  
Selective Laser Sintering ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Laser Sintering ◽  
Sisal Fiber ◽  
Preheating Temperature ◽  
Scan Speed

A new type of sustainable material, i.e., a sisal fiber/poly-ether sulfone composite (SFPC), which is energy-efficient, environmentally friendly, and has a low cost, was developed for laser sintering additive manufacturing. This study was performed to explore the effects of the processing parameters on the SFPC composite parts produced via selective laser sintering (SLS). The effects of the laser sintering processing parameters, i.e., the preheating temperature, laser power, and scan speed, were studied. Bending and tensile testing of the SFPC specimens was successfully performed via SLS. The effect of the processing parameters on the SLS in terms of the mechanical strength of the laser-sintered parts was investigated. The results determined that the processing parameters had a significant effect on the mechanical strength of the sintered SFPC parts. When the preheating temperature and laser power were increased in the processing SLS system, the mechanical strength of the sintered SFPC parts was significantly increased. However, the scanning speed had an inverse proportional relationship to the mechanical strength of the SFPC SLS parts.

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