Comparison of Flowability and Sinterability Among Different Binder Jetting Feedstock Powders: Nanopowder, Micropowder, and Granulated Powder

2021 ◽  
Vol 9 (2) ◽  
Author(s):  
Wenchao Du ◽  
Guanxiong Miao ◽  
Zhijian Pei ◽  
Chao Ma
Keyword(s):  
Particle Size ◽  
Flow Rate ◽  
Freeze Drying ◽  
Volumetric Flow Rate ◽  
Granule Size ◽  
Hausner Ratio ◽  
Tap Density ◽  
Spray Freeze Drying ◽  
Binder Jetting ◽  
High Flowability

Abstract Feedstock powders used in binder jetting additive manufacturing include nanopowder, micropowder, and granulated powder. Two important characteristics of the feedstock powders are flowability and sinterability. This paper aims to compare the flowability and sinterability of different feedstock powders. Three powders were compared: nanopowder (with a particle size of ∼100 nm), micropowder (with a particle size of 70 μm), and granulated powder (with a granule size of ∼70 μm) made from the nanopowder by spray freeze drying. Flowability metrics employed included apparent density (AD), tap density (TD), volumetric flow rate (VFR), mass flow rate (MFR), Hausner ratio (HR), Carr index (CI), and repose angle (RA). Sinterability metrics employed included sintered bulk density (SBD), volumetric shrinkage (VS), and densification ratio (DR). Results show that the granulated powder has a higher flowability than the nanopowder and a higher sinterability than the micropowder. Moreover, different flowability metric values of the granulated powder are close to those of the micropowder, indicating that these two powers have a comparably high flowability. Similarly, different sinterability metric values of the granulated powder are close to those of the nanopowder, indicating that these two powders have a comparably high sinterability.

Binder Jetting Additive Manufacturing of Ceramics: Comparison of Flowability and Sinterability Between Raw and Granulated Powders

2019 ◽  
Author(s):  
Wenchao Du ◽  
Guanxiong Miao ◽  
Lianlian Liu ◽  
Zhijian Pei ◽  
Chao Ma
Keyword(s):  
Additive Manufacturing ◽  
Flow Rate ◽  
Freeze Drying ◽  
Volumetric Flow Rate ◽  
Hausner Ratio ◽  
Spray Freeze Drying ◽  
Material Preparation ◽  
Binder Jetting ◽  
High Flowability

Abstract The objective of this study is to compare three different feedstock powders for the binder jetting process by characterizing their flowability and sinterability. Binder jetting additive manufacturing is a promising technology for fabricating ceramic parts with complex or customized geometries. Granulation is a promising material preparation method due to the potential high sinterability and flowability of the produced powder. However, no study has been made to systematically compare raw and granulated powders in terms of their flowing and sintering behaviors. This paper aims at filling this knowledge gap. Two raw powders (i.e., fine raw powder of 300 nm and coarse raw powder of 70 μm) and one granulated powder from spray freeze drying were compared. Different flowability metrics, including volumetric flow rate, mass flow rate, Hausner ratio, Carr index, and repose angle were measured. Different sinterability metrics, including sintered bulk density, volume shrinkage, and densification ratio were compared for all three powders. Results show that granulated powder achieved comparably high flowability to that of the coarse raw powder and also comparably high sinterability to that of the fine raw powder. Moreover, suitable metrics for the characterization of the sinterability and flowability for these three powders are recommended. This study suggests spray freeze drying produces high-quality feedstock powder for binder jetting process.

Binder Jetting Additive Manufacturing of Ceramics: Feedstock Powder Preparation by Spray Freeze Granulation

2019 ◽  
Author(s):  
Wenchao Du ◽  
Guanxiong Miao ◽  
Lianlian Liu ◽  
Zhijian Pei ◽  
Chao Ma
Keyword(s):  
Particle Size ◽  
Additive Manufacturing ◽  
Feed Rate ◽  
Freeze Drying ◽  
Granule Size ◽  
Feedstock Powder ◽  
Powder Preparation ◽  
Promising Technology ◽  
Spray Freeze Drying ◽  
Binder Jetting

Abstract Objective of this study is to prepare the binder jetting feedstock powder by spray freeze drying and study the effects of its parameters on the powder properties. Binder jetting additive manufacturing is a promising technology for fabricating ceramic parts with complex or customized geometries. However, this process is limited by the relatively low density of the fabricated parts even after sintering. The main cause comes from the contradicting requirements of the particle size of the feedstock powder: a large particle size (> 5 μm) is required for a high flowability while a small particle size (< 1 μm) for a high sinterability. For the first time, a novel technology for the feedstock material preparation, called spray freeze drying, is investigated to address this contradiction. Using raw alumina nanopowder (100 nm), a full factorial design at two levels for two factors (spraying pressure and slurry feed rate) was formed to study their effects on the properties (i.e., granule size, flowability, and sinterability) of the obtained granulated powder. Results show that high pressure and small feed rate lead to small granule size. Compared with the raw powder, the flowability of the granulated powders was significantly increased, and the high sinterability was also maintained. This study proves that spray freeze granulation is a promising technology for the feedstock powder preparation of binder jetting additive manufacturing.

scholarly journals Evaluation of Process Conditions for Ultrasonic Spray-Freeze Drying of Transglutaminase

2020 ◽  
Vol 58 (1) ◽  
pp. 38-48
Author(s):  
Hilal Isleroglu ◽  
Izzet Turker
Keyword(s):  
Enzyme Activity ◽  
Flow Rate ◽  
Freeze Drying ◽  
Desirability Function ◽  
Spherical Particles ◽  
Optimum Process ◽  
Process Conditions ◽  
Plate Temperature ◽  
Ultrasonic Spray ◽  
Spray Freeze Drying

In this study, a commercial transglutaminase enzyme was dried using an ultrasonic spray freeze drying method and the effects of the process conditions were optimized to maximize the final transglutaminase activity. Accordingly, process parameters affecting enzyme activity were selected, such as nozzle frequency (48 and 120 kHz), flow rate (2, 5 and 8 mL/min) and plate temperature for secondary drying (25, 35 and 45 °C). Moreover, the effects of different pH values (pH=2.0 and 9.0) and high temperature (80 °C) on enzyme activity, physical properties and particle morphology of transglutaminase were discussed. According to the results, transglutaminase preserved its activity despite ultrasonic spray freeze drying. Sonication enhanced the enzyme activity. Using the desirability function method, the optimum process conditions were determined to be flow rate 3.10 mL/min, plate temperature 45 °C and nozzle frequency 120 kHz. The predicted activity ratio was 1.17, and experimentally obtained ratio was 1.14±0.02. Furthermore, enzyme produced by ultrasonic spray freeze drying had low moisture values (2.92-4.36 %) at 8 h of drying. When the morphological structure of the transglutaminase particles produced by ultrasonic spray freeze drying under the optimum conditions was examined, spherical particles with pores on their surfaces were observed. In addition, flow properties of the transglutaminase powders were considered as fair under most conditions according to the Carr index.

Protein spray freeze drying. 2. Effect of formulation variables on particle size and stability

2002 ◽  
Vol 91 (2) ◽  
pp. 388-395 ◽  
Author(s):  
Henry R. Costantino ◽  
Laleh Firouzabadian ◽  
Chichih Wu ◽  
Karen G. Carrasquillo ◽  
Kai Griebenow ◽  
...  
Keyword(s):  
Particle Size ◽  
Freeze Drying ◽  
Spray Freeze Drying ◽  
Formulation Variables

Binder Jetting Additive Manufacturing: Effect of Particle Size Distribution on Density

2021 ◽  
Vol 143 (9) ◽  
Author(s):  
Wenchao Du ◽  
Jorge Roa ◽  
Jaehee Hong ◽  
Yanwen Liu ◽  
Zhijian Pei ◽  
...  
Keyword(s):  
Particle Size ◽  
Packing Density ◽  
Density Ratio ◽  
Size Ratio ◽  
Powder Bed ◽  
Particle Size Ratio ◽  
Tap Density ◽  
Mixing Method ◽  
Component Particle ◽  
Binder Jetting

Abstract This paper reports a study on the effects of particle size distribution (tuned by mixing different-sized powders) on density of a densely packed powder, powder bed density, and sintered density in binder jetting additive manufacturing. An analytical model was used first to study the mixture packing density. Analytical results showed that multimodal (bimodal or trimodal) mixtures could achieve a higher packing density than their component powders and there existed an optimal mixing fraction to achieve the maximum mixture packing density. Both a lower component particle size ratio (fine to coarse) and a larger component packing density ratio (fine to coarse) led to a larger maximum mixture packing density. A threshold existed for the component packing density ratio, below which the mixing method was not effective for density improvement. Its relationship to the component particle size ratio was calculated and plotted. In addition, the dependence of the optimal mixing fraction and maximum mixture packing density on the component particle size ratio and component packing density ratio was calculated and plotted. These plots can be used as theoretical tools to select parameters for the mixing method. Experimental results of tap density were consistent with the above-mentioned analytical predictions. Also, experimental measurements showed that powders with multimodal particle size distributions achieved a higher tap density, powder bed density, and sintered density in most cases.

scholarly journals Inhalable Protein Powder Prepared by Spray-Freeze-Drying Using Hydroxypropyl-β-Cyclodextrin as Excipient

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 615
Author(s):  
Jason C. K. Lo ◽  
Harry W. Pan ◽  
Jenny K. W. Lam
Keyword(s):  
Protein Aggregation ◽  
Flow Rate ◽  
Freeze Drying ◽  
Gas Flow ◽  
Feed Solution ◽  
Solute Concentration ◽  
Gas Flow Rate ◽  
Aerosol Performance ◽  
Spray Freeze Drying ◽  
Induced Aggregation

The prospect of inhaled biologics has garnered particular interest given the benefits of the pulmonary route of administration. Pertinent considerations in producing inhalable dry powders containing biological medicines relate to aerosol performance and protein stability. Spray-freeze-drying (SFD) has emerged as an established method to generate microparticles that can potentially be deposited in the lungs. Here, the SFD conditions and formulation composition were evaluated using bovine serum albumin (BSA) as a model protein and 2-hydroxypropyl-beta-cyclodextrin (HPβCD) as the protein stabilizer. A factorial design analysis was performed to investigate the effects of BSA content, solute concentration of feed solution, and atomization gas flow rate on dispersibility (as an emitted fraction), respirability (as fine particle fraction), particle size, and level of protein aggregation. The atomization gas flow rate was identified as a significant factor in influencing the aerosol performance of the powder formulations and protein aggregation. Nonetheless, high atomization gas flow rate induced aggregation, highlighting the need to further optimize the formulation. Of note, all the formulations exhibited excellent dispersibility, while no fragmentation of BSA occurred, indicating the feasibility of SFD and the promise of HPβCD as an excipient.

scholarly journals Spray-freeze-drying of nanosuspensions: the manufacture of insulin particles for needle-free ballistic powder delivery

2010 ◽  
Vol 7 (suppl_4) ◽  
Author(s):  
Heiko Schiffter ◽  
Jamie Condliffe ◽  
Sebastian Vonhoff
Keyword(s):  
Size Distribution ◽  
Freeze Drying ◽  
Size Exclusion ◽  
Insulin Content ◽  
Size Distributions ◽  
Narrow Size Distribution ◽  
Matrix Formulation ◽  
Tap Density ◽  
Spray Freeze Drying ◽  
Insulin Stability

The feasibility of preparing microparticles with high insulin loading suitable for needle-free ballistic drug delivery by spray-freeze-drying (SFD) was examined in this study. The aim was to manufacture dense, robust particles with a diameter of around 50 µm, a narrow size distribution and a high content of insulin. Atomization using ultrasound atomizers showed improved handling of small liquid quantities as well as narrower droplet size distributions over conventional two-fluid nozzle atomization. Insulin nanoparticles were produced by SFD from solutions with a low solid content (<10 mg ml −1 ) and subsequent ultra-turrax homogenization. To prepare particles for needle-free ballistic injection, the insulin nanoparticles were suspended in matrix formulations with a high excipient content (>300 mg ml −1 ) consisting of trehalose, mannitol, dextran (10 kDa) and dextran (150 kDa) (abbreviated to TMDD) in order to maximize particle robustness and density after SFD. With the increase in insulin content, the viscosity of the nanosuspensions increased. Liquid atomization was possible up to a maximum of 250 mg of nano-insulin suspended in a 1.0 g matrix. However, if a narrow size distribution with a good correlation between theoretical and measurable insulin content was desired, no more than 150 mg nano-insulin could be suspended per gram of matrix formulation. Particles were examined by laser light diffraction, scanning electron microscopy and tap density testing. Insulin stability was assessed using size exclusion chromatography (SEC), reverse phase chromatography and Fourier transform infrared (FTIR) spectroscopy. Densification of the particles could be achieved during primary drying if the product temperature ( T prod ) exceeded the glass transition temperature of the freeze concentrate ( T g ′) of −29.4°C for TMDD (3∶3∶3∶1) formulations. Particles showed a collapsed and wrinkled morphology owing to viscous flow of the freeze concentrate. With increasing insulin loading, the d ( v , 0.5) of the SFD powders increased and particle size distributions got wider. Insulin showed a good stability during the particle formation process with a maximum decrease in insulin monomer of only 0.123 per cent after SFD. In accordance with the SEC data, FTIR analysis showed only a small increase in the intermolecular β-sheet of 0.4 per cent after SFD. The good physical stability of the polydisperse particles made them suitable for ballistic injection into tissue-mimicking agar hydrogels, showing a mean penetration depth of 251.3 ± 114.7 µm.

Pyrolysis of brown algae (Bifurcaria Bifurcata) in a stainless steel tubular reactor: From a review to a case study

2018 ◽  
Vol 14 (1) ◽  
pp. 31-60 ◽  
Author(s):  
M. Y. Guida ◽  
F. E. Laghchioua ◽  
A. Hannioui
Keyword(s):  
Particle Size ◽  
Stainless Steel ◽  
Flow Rate ◽  
Brown Algae ◽  
Tubular Reactor ◽  
Nitrogen Flow ◽  
Nitrogen Flow Rate ◽  
Bifurcaria Bifurcata ◽  
Bio Oil

This article deals with fast pyrolysis of brown algae, such as Bifurcaria Bifurcata at the range of temperature 300–800 °C in a stainless steel tubular reactor. After a literature review on algae and its importance in renewable sector, a case study was done on pyrolysis of brown algae especially, Bifurcaria Bifurcata. The aim was to experimentally investigate how the temperature, the particle size, the nitrogen flow rate (N2) and the heating rate affect bio-oil, bio-char and gaseous products. These parameters were varied in the ranges of 5–50 °C/min, below 0.2–1 mm and 20–200 mL. min–1, respectively. The maximum bio-oil yield of 41.3wt% was obtained at a pyrolysis temperature of 600 °C, particle size between 0.2–0.5 mm, nitrogen flow rate (N2) of 100 mL. min–1 and heating rate of 5 °C/min. Liquid product obtained under the most suitable and optimal condition was characterized by elemental analysis, 1H-NMR, FT-IR and GC-MS. The analysis of bio-oil showed that bio-oil from Bifurcaria Bifurcata could be a potential source of renewable fuel production and value added chemicals.

Utilization of Waste of Enzymes Biomass as Biosorbent for the Removal of Dyes from Aqueous Solution in Batch and Fluidized Bed Column

2020 ◽  
Vol 71 (1) ◽  
pp. 1-12
Author(s):  
Salman H. Abbas ◽  
Younis M. Younis ◽  
Mohammed K. Hussain ◽  
Firas Hashim Kamar ◽  
Gheorghe Nechifor ◽  
...  
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Particle Size ◽  
Adsorption Capacity ◽  
Fluidized Bed ◽  
Flow Rate ◽  
Fungal Biomass ◽  
Solution Flow Rate ◽  
Maximum Adsorption Capacity ◽  
Solution Flow

The biosorption performance of both batch and liquid-solid fluidized bed operations of dead fungal biomass type (Agaricusbisporus ) for removal of methylene blue from aqueous solution was investigated. In batch system, the adsorption capacity and removal efficiency of dead fungal biomass were evaluated. In fluidized bed system, the experiments were conducted to study the effects of important parameters such as particle size (701-1400�m), initial dye concentration(10-100 mg/L), bed depth (5-15 cm) and solution flow rate (5-20 ml/min) on breakthrough curves. In batch method, the experimental data was modeled using several models (Langmuir,Freundlich, Temkin and Dubinin-Radushkviechmodels) to study equilibrium isotherms, the experimental data followed Langmuir model and the results showed that the maximum adsorption capacity obtained was (28.90, 24.15, 21.23 mg/g) at mean particle size (0.786, 0.935, 1.280 mm) respectively. In Fluidized-bed method, the results show that the total ion uptake and the overall capacity will be decreased with increasing flow rate and increased with increasing initial concentrations, bed depth and decreasing particle size.

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