scholarly journals Investigating the Potential Plasticizing Effect of Di-Carboxylic Acids for the Manufacturing of Solid Oral Forms with Copovidone and Ibuprofen by Selective Laser Sintering

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3282
Author(s):  
Yanis Abdelhamid Gueche ◽  
Noelia M. Sanchez-Ballester ◽  
Bernard Bataille ◽  
Adrien Aubert ◽  
Jean-Christophe Rossi ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Heating Temperature ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Scanning Calorimetry ◽  
Disintegration Time ◽  
Polymer Powder ◽  
Tartaric Acids ◽  
The Stability ◽  
Optimal Heating

In selective laser sintering (SLS), the heating temperature is a critical parameter for printability but can also be deleterious for the stability of active ingredients. This work aims to explore the plasticizing effect of di-carboxylic acids on reducing the optimal heating temperature (OHT) of polymer powder during SLS. First, mixtures of copovidone and di-carboxylic acids (succinic, fumaric, maleic, malic and tartaric acids) as well as formulations with two forms of ibuprofen (acid and sodium salt) were prepared to sinter solid oral forms (SOFs), and their respective OHT was determined. Plasticization was further studied by differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). Following this, the printed SOFs were characterized (solid state, weight, hardness, disintegration time, drug content and release). It was found that all acids (except tartaric acid) reduced the OHT, with succinic acid being the most efficient. In the case of ibuprofen, only the acid form demonstrated a plasticizing effect. DSC and FTIR corroborated these observations showing a decrease in the glass transition temperature and the presence of interactions, respectively. Furthermore, the properties of the sintered SOFs were not affected by plasticization and the API was not degraded in all formulations. In conclusion, this study is a proof-of-concept that processability in SLS can improve with the use of di-carboxylic acids.

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.

Study in performance and morphology of polyamide 12 produced by selective laser sintering technology

2018 ◽  
Vol 24 (5) ◽  
pp. 813-820 ◽  
Author(s):  
Junjie Wu ◽  
Xiang Xu ◽  
Zhihao Zhao ◽  
Minjie Wang ◽  
Jie Zhang
Keyword(s):  
Selective Laser Sintering ◽  
Polarized Light ◽  
Chain Scission ◽  
High Energy ◽  
Laser Sintering ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Content Type ◽  
X Ray ◽  
Polyamide 12

Purpose The purpose of this paper is to investigate the effect of selective laser sintering (SLS) method on morphology and performance of polyamide 12. Design/methodology/approach Crystallization behavior is critical to the properties of semi-crystalline polymers. The crystallization condition of SLS process is much different from others. The morphology of polyamide 12 produced by SLS technology was investigated using scanning electron microscopy, polarized light microscopy, differential scanning calorimetry, X-ray diffraction and wide-angle X-ray diffraction. Findings Too low fill laser power brought about bad fusion of powders, while too high energy input resulted in bad performance due to chain scission of macromolecules. There were three types of crystal in the raw powder material, denoted as overgrowth crystal, ring-banded spherulite and normal spherulite. Originality/value In this work, SLS samples with different sintering parameters, as well as compression molding sample for the purpose of comparison, were made to study the morphology and crystal structure of sintered PA12 in detail.

scholarly journals Analysis of Tribo-Charging during Powder Spreading in Selective Laser Sintering: Assessment of Polyamide 12 Powder Ageing Effects on Charging Behavior

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 609 ◽  
Author(s):  
Nicolas Hesse ◽  
Maximilian Dechet ◽  
Juan Bonilla ◽  
Christian Lübbert ◽  
Stephan Roth ◽  
...  
Keyword(s):  
Selective Laser Sintering ◽  
Electrostatic Charge ◽  
Laser Sintering ◽  
Process Stability ◽  
Polyamide 12 ◽  
Part Quality ◽  
Polymer Powder ◽  
Novel Approach ◽  
Powder Flowability ◽  
Model Setup

Powder flowability is key to achieving high process stability and part quality by application of smooth and dense layers in selective laser sintering (SLS). This study sheds light on the rarely investigated effect of tribo-electric charge build-up during powder delivery in the SLS process. This is achieved by a novel approach to quantify electrostatic potentials during doctor blading. The presented model setup is used in combination with charge spectrometry and impedance spectroscopy to investigate the alterations in tribo-electric charging behavior for the most commonly used laser sintering material polyamide 12 in its virgin and aged, c.f. reused, states. We show that the electrostatic charge build-up is significantly enhanced for aged polymer powder material, likely contributing to altered performance in SLS processing.

Fundamental investigation of part properties at accelerated beam speeds in the selective laser sintering process

2017 ◽  
Vol 23 (6) ◽  
pp. 1099-1106 ◽  
Author(s):  
Matthias Michael Lexow ◽  
Maximilian Drexler ◽  
Dietmar Drummer
Keyword(s):  
Mechanical Properties ◽  
Heating Rate ◽  
Energy Input ◽  
Selective Laser Sintering ◽  
Stable Process ◽  
Peak Height ◽  
Laser Sintering ◽  
Scanning Calorimetry ◽  
Content Type ◽  
The Core

Purpose Despite the recent progress in basic process understanding considering the selective laser sintering (SLS) of thermoplastics, several aspects of the mechanisms of the beam and powder interaction are not fully understood yet. Recent studies covered the correlation of mechanical properties and part density with the heating rate. The surface roughness of the test specimens was also considered but showed no distinct relation to the part mechanics. The purpose of this paper is to provide a new fundamental model for describing the decreasing mechanical properties with increasing beam speed. Design/methodology/approach While the dependence of mechanical properties with total energy input during exposure is well published, the correlation of the exposure speed with the degree of particle melt (DPM) is the subject of the present study. The DPM is accessible through differential scanning calorimetry measurements. Supporting the previously introduced method of the core-peak height, the interpretation via the core-peak area is proposed as a means to ascertain the melting behaviour for different processing conditions. Further support of the observations is given by x-ray computed tomography and microscopy which allows for a correlation with the respective porosity and inner structure of the parts. Findings The authors show a novel way of describing the decreasing mechanical properties with increasing speed of energy input by showing the dependence of the DPM on the heating rate during exposure. Practical implications The results offer an addition to the understanding considering the reliability and reproducibility of the SLS process. Originality/value The paper extends the existing models of the time-dependent material behaviour, which allows for the derivation of new efficient and stable process strategies.

Physical characteristics of selective laser sintering of metal—polymer powder composites

1998 ◽  
Vol 28 (5) ◽  
pp. 420-425 ◽  
Author(s):  
A M Ivanova ◽  
S P Kotova ◽  
N L Kupriyanov ◽  
A L Petrov ◽  
E Yu Tarasova ◽  
...  
Keyword(s):  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Physical Characteristics ◽  
Polymer Powder ◽  
Powder Composites ◽  
Metal Polymer

3D Modeling of Additive Manufacturing Process: The Case of Polymer Laser Sintering

2020 ◽  
Author(s):  
Lan Zhang ◽  
M'hamed Boutaous ◽  
Shihe Xin ◽  
Dennis A. Siginer
Keyword(s):  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Heat Diffusion ◽  
Laser Scattering ◽  
Transient Phenomena ◽  
Powder Bed ◽  
Process Characteristics ◽  
Polymer Powder ◽  
Volume Method ◽  
Air Diffusion

Abstract This work focusses on studying multiphysical transient phenomena in polymer powders occurring during selective laser sintering in polymers powders. Multiple phenomena stemming from the interaction of the laser with the polymer powder bed and the transfer of the laser power to the powder bed including laser scattering and absorption, polymer heating, melting, coalescence, densification, and the variation of the material parameters with the temperature are simulated via the modified Monte Carlo-ray tracing method coupled with the Mie theory. A finite volume method is adopted for the heat transfer. The model couples heat diffusion, melting, coalescence and densification of the polymer grains, and the crystallization kinetics during the cooling steps. Laser intensity is concentrated on the surface of the material contrary to the predictions of the Beer-Lambert law. Laser acting on thermoplastic material cause the polymer powder melt, coalescence between melted grains, air diffusion versus densification, crystallization and volume shrinkage. All these processes are simulated by a series of multiphysical models. The reliability of the modeling is tested by comparison with experiments in the literature, and a parametric analysis is performed, based on the process characteristics such as laser sweep speed, its intensity and shape, polymeric grain size among others. Several recommendations to optimize the process are proposed.

scholarly journals Recycling of Selective Laser Sintering Waste Nylon Powders into Fused Filament Fabrication Parts Reinforced with Mg Particles

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2046
Author(s):  
Mohammad Uddin ◽  
Daniel Williams ◽  
Anton Blencowe
Keyword(s):  
Flexural Strength ◽  
Moisture Absorption ◽  
Selective Laser Sintering ◽  
Thermal Characteristics ◽  
Melt Flow Index ◽  
Laser Sintering ◽  
Flow Index ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
Dog Bone

This paper presents recycling of selective laser sintering (SLS) waste nylon into printable filaments and parts reinforced with Mg particles. Waste nylon and waste–Mg powder mixture with 2%, 4%, and 8% Mg to nylon were extruded into the filaments. Moisture absorption, differential scanning calorimetry, and melt flow index experiments were conducted to determine the thermal characteristics, while tensile and flexural tests were conducted to evaluate mechanical properties and failure mechanisms. The results were compared with off-the-self (OTS) nylon. Waste powder was found to be extrudable and printable as FFF filament. Waste filament diameter closely matched standard filament size, while exhibiting reduced moisture absorption. High melting and crystallisation temperature for the waste nylon demonstrated a degradation of the plastic during the SLS process. Young’s modulus and ultimate tensile strength for the waste filament increased by 1.6-fold compared to that for OTS, while Mg-composite filament surpassed the waste and OTS. Waste and Mg composite dog bone results showed an increase in strength and stiffness, but the ductility deteriorated. Both flexural strength and modulus for the waste nylon increased by 13% and 26%, respectively, over OTS, and the addition of Mg enhanced flexural strength by up to 5-fold at 8% Mg over the waste. Printed surface topography demonstrated that the waste and Mg composite filaments can print the parts with desired geometric shapes and acceptable surface texture. The findings showed that recycling waste SLS powder into FFF prints would be a viable and useful alternative to disposal, given its abundance.

Study on Sucrose Powder in Selective Laser Sintering Mechanism

2014 ◽  
Vol 541-542 ◽  
pp. 209-213 ◽  
Author(s):  
Lai Xia Yang ◽  
Xu Sheng Yao ◽  
Ying Bao Xue
Keyword(s):  
Weight Loss ◽  
Melting Point ◽  
Heating Temperature ◽  
Selective Laser Sintering ◽  
Thermo Gravimetric Analysis ◽  
Decomposition Temperature ◽  
Laser Sintering ◽  
Powder Materials ◽  
Gravimetric Analysis ◽  
Sintering Mechanism

In this paper, the selective laser sintering mechanism of sucrose powder materials were studied. This paper uses DSC/TG technology to sucrose by thermo gravimetric analysis. The results show that, the melting point of sucrose at 187 °C, its decomposition temperature at 220°C, 300°C after weight loss in more than 50%, sucrose and reasonable final heating temperature was between 187°C~220°C. The results show that, the melting point of sucrose at 187°C, its decomposition temperature at 220°C, 300°C after weight loss in more than 50%, sucrose and reasonable final heating temperature was between 187°C~220°C.

Investigation into the Differences Thermal Properties of SLS Polymer Powder Materials Using Differential Scanning Calorimetry (DSC)

2014 ◽  
Vol 548-549 ◽  
pp. 53-56
Author(s):  
Yusoff Way ◽  
Hadi Puwanto ◽  
M. Aichouni ◽  
Farizahani
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Polymer Materials ◽  
Powder Materials ◽  
Sintering Process ◽  
Scanning Calorimetry ◽  
Polyamide 12 ◽  
Materials Used

In order to produce good functional Laser Sintering (LS) parts, it is important that the powder on the part bed surface receives a sufficient amount of power energy through the laser sintering process. The reason is that sufficient energy density is produced when the energy input increases and is applied to the part bed surface, which causes a higher temperature, and thus better melt flow. The objective of this research is to investigate the thermal properties of polymer materials used in Selective Laser Sintering (SLS) processes. In this experiment, there were five different thermoplastics powders known as polyamide 12 (PA2200), Glass Fill Polyamide (GF3200), Alumide, Duraflex and CastForm were tested using Differential Scanning Calorimetry (DSC). This outcome of this research would assist the SLS users to improve the sintering process and quality of the part surface finish.

scholarly journals A Test Part for Evaluating the Accuracy and Resolution of a Polymer Powder Bed Fusion Process

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Jared Allison ◽  
Conner Sharpe ◽  
Carolyn Conner Seepersad
Keyword(s):  
Selective Laser Sintering ◽  
Statistical Design ◽  
Laser Sintering ◽  
Industrial Applications ◽  
Design Guidelines ◽  
Powder Bed Fusion ◽  
Sintering Process ◽  
Powder Bed ◽  
Test Part ◽  
Polymer Powder

Additive manufacturing (AM) has many potential industrial applications because highly complex parts can be fabricated with little or no tooling cost. One barrier to widespread use of AM, however, is that many designers lack detailed information about the capabilities and limitations of each process. To compile statistical design guidelines, comprehensive, statistically meaningful metrology studies need to be performed on AM technologies. In this paper, a test part is designed to evaluate the accuracy and resolution of the polymer powder bed fusion (PBF) or selective laser sintering process for a wide variety of features. The unique construction of this test part allows it to maximize feature density while maintaining a small build volume. As a result, it can easily fit into most existing selective laser sintering builds, without requiring dedicated builds, thereby facilitating the repetitive fabrication necessary for building statistical databases of design allowables. By inserting the part into existing builds, it is also possible to monitor geometric accuracy and resolution on a build- and machine-specific basis in much the same way that tensile bars are inserted to monitor structural properties. This paper describes the test part and its features along with a brief description of the measurements performed on it and a representative sample of the types of geometric data derived from it.

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