Juan Sebastian Gomez Bonilla- Master of Science
- Process engineer at FMP Technology
Juan Sebastian Gomez Bonilla
- Master of Science
- Process engineer at FMP Technology
About
19
Publications
6,203
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
287
Citations
Introduction
Juan Gomez is currently working at the Institute of Particle Technology of the Friedrich-Alexander University Erlangen-Nurnberg. His research topics involve the functionalization of polymer particles by means of gas phase processes i.e. particle rounding, plasma functionalization, PECVD coating of particles.
Current institution
FMP Technology
Current position
- Process engineer
Publications
Publications (19)
The present work focuses on investigating the residence time behavior of microparticles in a concurrent downer reactor through experiments and numerical simulations. For the numerical simulations, a three-dimensional multiphase model was developed using the Euler-Lagrange approach. The experiments were performed in a 0.8 m-long steel reactor with g...
Polypropylene (PP) powders are rounded at different conditions in a downer reactor with direct heating. The particles are fed through a single central tube, while the preheated sheath gas is fed coaxially surrounding the central aerosol jet. The influence of the process parameters on the quality of the powder product in terms of particle shape and...
Polypropylene (PP) powders are coated with silica nanoparticles in a fluidized bed to improve the flow behavior of the powders and the processability in powder bed fusion. The nanoparticles are produced in situ via dusty plasma‐enhanced chemical vapor deposition (PECVD) in an atmospheric‐pressure Ar/O2 plasma jet fixed at the distributor plate of t...
The development of a novel polybutylene terephthalate (PBT) feedstock material for powder bed fusion of polymers with laser beam (PBF-LB/P) by means of liquid-liquid phase separation (LLPS) and precipitation is outlined. Appropriate solvents for precipitation have been identified by a screening approach based on solubility parameters. Feasible syst...
Purpose
The purpose of this paper is to investigate the effect of different heating approaches during thermal rounding of polymer powders on powder bulk properties such as particle size, shape and flowability, as well as on the yield of process.
Design/methodology/approach
This study focuses on the rounding of commercial high-density polyethylene...
Polypropylene (PP) powder is treated in a fluidized bed reactor with an atmospheric Ar/O 2 plasma jet to investigate the influence of the plasma treatment on the coloring of the powders. The oxygen concentration in the plasma gas and duration of the treatment was varied. Contact angle and X-ray photoelectron spectroscopy measurements confirmed and...
In this work, the development and processing behavior of poly(L-lactide) (PLLA) particles for powder bed fusion (PBF) of polymers obtained via a green and sustainable process route are thoroughly studied. Liquid-liquid phase separation and precipitation from triacetin, a non-toxic solvent, are applied for the production of highly spherical PLLA par...
In this work, the development and processing behavior of poly(L-lactide) (PLLA) particles for powder bed fusion (PBF) of polymers obtained via a green and sustainable process route are thoroughly studied. Liquid-liquid phase separation and precipitation from triacetin, a non-toxic solvent, are applied for the production of highly spherical PLLA par...
Common techniques for the production of polymer powders for selective laser sintering (SLS) involve the comminution of polymers. Comminution of polymers often results in powders made of irregular shaped particles with a low bulk density and a bad flow behavior. With the aim to improve the flowability of grinded powders and, thus, the SLS processabi...
The processability of selective laser sintering (SLS) powders and the characteristics of the generated parts
depend amongst others on the flowability. To increase the flowability, SLS powders are usually functionalized
with flowing agents. Flowing agents are typically applied by dry particle coating. The optimization of the process
parameters neces...
Additive manufacturing processes allow the production of individualized and complex parts without the use of molds or tools. Especially powder and beam-based AM processes like selective laser sintering (SLS) of polymers are promising, although the choice of commercial SLS powders is very limited. To further extend the applications of SLS, new and c...
Flowability and packing properties are essential for powder spreading and resulting part properties in powder bed fusion processes (PBF), such as selective laser sintering (SLS). In this contribution, powder requirements for SLS, structure-property relationships and appropriate methods for powder characterization are reviewed. Effects of particle s...
Additive manufacturing techniques, such as powder bed fusion (PBF) of polymers, often referred to as laser sintering (LS) or selective laser sintering (SLS), generate components directly from a CAD data set without using a specific mold. The range of materials commercially available for SLS merely includes some semi-crystalline polymers, mainly pol...
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 electrosta...
In this study, the feasibility of co-grinding and the subsequent thermal rounding to produce spherical polymer blend particles for selective laser sintering (SLS) is demonstrated for polybutylene terephthalate (PBT) and polycarbonate (PC). The polymers are jointly comminuted in a planetary ball mill, and the obtained product particles are rounded i...
Polymer powder-based additive manufacturing technologies yield excellent mechanical and functional part qualities. One of these technologies is selective laser sintering (SLS), a process employing polymer particles, which are selectively fused by a laser. However, hardly any blend materials are available; mostly, the processing of multi-material sy...
In this work we present a study on operating a downer reactor for thermal rounding of polymer particles with direct, convective and indirect heating of the material. We show for high density polyethylene (HD-PE) that convective heating is beneficial with respect to yield and flowability of the product, conserving the degree of crystallinity, but le...
We apply X-ray computed tomography for non-invasive investigation of the distribution of solids over the cross-section of a pilot plant scale circulating fluidized bed riser and present a novel method to derive volumetric solids concentrations from tomographic raw data. In this, the elimination of low-energetic radiation from the incident X-ray spe...
Questions
Question (1)
Hello, I'm building a ALD reactor in lab scale and I have a few questions referring to the security of operation. As known, most of ALD precursors such as TMA are pyrophoric, but how dangerous can it be, when an exhaust gas composed of small amounts of TMA diluted in nitrogen come in contact with oxigen? what is the best way to deal with exhaust gases of this kind of precursors when discharging at the atmosphere?
