A novel process for production of spherical PBT powders and their processing behavior during laser beam melting

Schmidt, Jochen; Sachs, Marius; Zhao, Meng; Fanselow, Stephanie; Wudy, Katrin; Drexler, Maximilian; Drummer, Dietmar; Wirth, Karl‐Ernst

doi:10.1063/1.4942343

Cited by 9 publications

(5 citation statements)

References 8 publications

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“…Schmidt et al [8][9][10][11] produced powders by wet grinding PBT granules, then running the milled powder through a so-called downer reactor to obtain spherical particles. Parts consisting only of a single layer could be produced with laser sintering, but no mechanical properties were tested.…”

Section: Introductionmentioning

confidence: 99%

Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

2019

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This work describes the production of a spherical polybutylene terephthalate (PBT) powder and its processing with selective laser sintering (SLS). The powder was produced via melt emulsification, a continuous extrusion-based process. PBT was melt blended with polyethylene glycol (PEG), creating an emulsion of spherical PBT droplets in a PEG matrix. Powder could be extracted after dissolving the PEG matrix phase in water. The extrusion settings were adjusted to optimize the size and yield of PBT particles. After classification, 79 vol. % of particles fell within a range of 10–100 µm. Owing to its spherical shape, the powder exhibited excellent flowability and packing properties. After powder production, the width of the thermal processing (sintering) window was reduced by 7.6 °C. Processing of the powder on a laser sintering machine was only possible with difficulties. The parts exhibited mechanical properties inferior to injection-molded specimens. The main reason lied in the PBT being prone to thermal degradation and hydrolysis during the powder production process. Melt emulsification in general is a process well suited to produce a large variety of SLS powders with exceptional flowability.

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Section: Introductionmentioning

confidence: 99%

Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

2019

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“…Schmid et al [58,59] presented a process chain for the production of spherical polybutylene terephthalate (PBT) microparticles. Their PBT powder, having a melting point of 223 • C, could be processed using a building temperature of 210 • C. Overall, by carrying out a rounding and a drying process on powder particles, it was possible to obtain a material suitable for 3D printing.…”

Section: Other Pure Polymers and Polymer Blendsmentioning

confidence: 99%

Additive Manufactured Parts Produced Using Selective Laser Sintering Technology: Comparison between Porosity of Pure and Blended Polymers

Morano,

Pagnotta

2023

Polymers

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For different manufacturing processes, porosity occurs in parts made using selective laser sintering (SLS) technology, representing one of the weakest points of materials produced with these processes. Even though there are different studies involving many polymeric materials employed via SLS, and different manuscripts in the literature that discuss the porosity occurrence in pure or blended polymers, to date, no researcher has reported a systematic and exhaustive comparison of the porosity percentage. A direct comparison of the available data may prove pivotal in advancing our understanding within the field of additively manufactured polymers. This work aims to collect and compare the results obtained by researchers who have studied SLS’s applicability to different amorphous or semi-crystalline polymers and pure or blended materials. In particular, the porosity values obtained by different researchers are compared, and tables are provided that show, for each material, the process parameters and the measured porosity values.

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“…All these interconnected effects along the whole process chain influence the final mechanical and functional properties of the produced parts (Kleijnen et al, 2019). The effect of particle shape and surface functionalization on particle interactions, powder spreadability and quality of L-PBFproduced specimen were investigated by Schmidt et al for a process chain consisting of (wet) comminution of polymers (Schmidt et al, 2012), thermal rounding in a heated downer reactor (Sachs et al, 2017;Gómez Bonilla et al, 2021b) and dry particle coating in a tumbling mixer for polystyrene (PS) (Schmidt et al, 2014;Schmidt et al, 2015), polybutylene terephthalate (PBT) (Schmidt et al, 2016a;Schmidt et al, 2016b;Schmidt et al, 2016c) and composite powder systems (filled systems, e.g. PBT-glass, PBT-Al 2 O 3 and blends, e.g.…”

Section: Figurementioning

confidence: 99%

Dry powder coating in additive manufacturing

Schmidt

Peukert

2022

Front. Chem. Eng.

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Dry powder coating is used in many industries to tailor the bulk solid characteristics of cohesive powders. Within this paper, the state of the art of dry coating of feedstock materials for powder based additive manufacturing (AM) processes will be reviewed. The focus is on feedstock materials for powder bed fusion AM processes, such as powder bed fusion of polymers with a laser beam and powder bed fusion of metals with lasers or an electron beam. Powders of several microns to several ten microns in size are used and the feedstock’s bulk solid properties, especially the flowability and packing density are of immanent importance in different process steps in particular for powder dosing and spreading of powder layers onto the building area. All these properties can be tuned by dry particle coating. Moreover, possibilities to improve AM processability and to manipulate the resulting microstructure (c.f. grain refinement, dispersion strengthening) by adhering nanoparticles on the powders will be discussed. The effect of dry coating on the obtained powder properties along the whole AM process chain and the resulting part properties is assessed. Moreover, appropriate characterization methods for bulk solid properties of dry-coated AM powders are critically discussed.

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A novel process for production of spherical PBT powders and their processing behavior during laser beam melting

Cited by 9 publications

References 8 publications

Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

Additive Manufactured Parts Produced Using Selective Laser Sintering Technology: Comparison between Porosity of Pure and Blended Polymers

Dry powder coating in additive manufacturing

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