Enabling triboelectric charging as a powder charging method for electrophotographic powder application in laser-based powder bed fusion of polymers by triboelectric charge control

Kopp, Sebastian-Paul; Düsenberg, Björn; Eshun, Pius  Marcellinus; Schmidt, Jochen; Bück, Andreas; Roth, Stephan; Schmidt, Michael

doi:10.1016/j.addma.2023.103531

Cited by 3 publications

(4 citation statements)

References 46 publications

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“…First, the powder and a photoconductive plate (PCP, aluminum plate coated with photoconductive material) are homogeneously charged [28][29][30]. In EPA, powder particles can be charged via gas discharge or triboelectrically [31][32][33]. While gas discharge-based powder charging does not require any further functionalization of the particles in terms of their charging behavior, for triboelectric charging, the particles need to be functionalized with charge-control agents (CCAs) [33].…”

Section: Introduction Technology 2: Material-efficient Am Of Multi-ma...mentioning

confidence: 99%

“…In EPA, powder particles can be charged via gas discharge or triboelectrically [31][32][33]. While gas discharge-based powder charging does not require any further functionalization of the particles in terms of their charging behavior, for triboelectric charging, the particles need to be functionalized with charge-control agents (CCAs) [33]. However, as described in [31][32][33], triboelectric charging offers some considerable advantages compared with gas discharge-based powder charging.…”

Section: Introduction Technology 2: Material-efficient Am Of Multi-ma...mentioning

confidence: 99%

“…While gas discharge-based powder charging does not require any further functionalization of the particles in terms of their charging behavior, for triboelectric charging, the particles need to be functionalized with charge-control agents (CCAs) [33]. However, as described in [31][32][33], triboelectric charging offers some considerable advantages compared with gas discharge-based powder charging. In the case of triboelectric powder charging, the powder flowability, which, in many cases, renders the usage of certain powders impossible for PBF-LB/P, does not play any role in powder application.…”

Section: Introduction Technology 2: Material-efficient Am Of Multi-ma...mentioning

confidence: 99%

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Innovative Process Strategies in Powder-Based Multi-Material Additive Manufacturing

Setter

Hafenecker

Rothfelder

et al. 2023

JMMP

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Multi-material additive manufacturing (AM) attempts to utilize the full benefits of complex part production with a comprehensive and complementary material spectrum. In this context, this research article presents new processing strategies in the field of polymer- and metal-based multi-material AM. The investigation highlights the current progress in powder-based multi-material AM based on three successfully utilized technological approaches: additive and formative manufacturing of hybrid metal parts with locally adapted and tailored properties, material-efficient AM of multi-material polymer parts through electrophotography, and the implementation of UV-curable thermosets within the laser-based powder bed fusion of plastics. Owing to the complex requirements for the mechanical testing of multi-material parts with an emphasis on the transition area, this research targets an experimental shear testing set-up as a universal method for both metal- and polymer-based processes. The method was selected based on the common need of all technologies for the sufficient characterization of the bonding behavior between the individual materials.

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Section: Introduction Technology 2: Material-efficient Am Of Multi-ma...mentioning

confidence: 99%

Section: Introduction Technology 2: Material-efficient Am Of Multi-ma...mentioning

confidence: 99%

Section: Introduction Technology 2: Material-efficient Am Of Multi-ma...mentioning

confidence: 99%

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Innovative Process Strategies in Powder-Based Multi-Material Additive Manufacturing

Setter

Hafenecker

Rothfelder

et al. 2023

JMMP

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“…CCAs are frequently ion surfactants or metal soaps that produce inverse micelles in the liquid dispersant [11]. Toner materials or particles can be charged positively or negatively depending on the particle materials and CCA employed [12]. Christie [13] defines CCAs as compounds that aid the management of the electrostatic charge applied during the printing process.…”

Section: Introductionmentioning

confidence: 99%

Encapsulation of Carbon Nanotubes by Styrene and Butyl Acrylate Particles via Suspension Polymerization for Polymerized Toner Applications

2023

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Electrophotographic printing and copying processes primarily use toner, which is a mixture of colorant, polymer, and additives. Toner can be made using traditional mechanical milling techniques or more contemporary chemical polymerization techniques. Suspension polymerization provides spherical particles with less stabilizer adsorption, homogeneous monomers, higher purity, and easier control of the reaction temperature. In contrast to these advantages, however, the particle size resulting from suspension polymerization is too large for toner. To overcome this disadvantage, devices such as high-speed stirrers and homogenizers can be used to reduce the size of the droplets. This research investigated the use of carbon nanotubes (CNTs) instead of carbon black as the pigment in toner development. We succeeded in achieving a good dispersion of four different types of CNT, specifically modified with NH2 and Boron or unmodified with long or short chains in water rather than chloroform, using sodium n-dodecyl sulfate as a stabilizer. We then performed polymerization of the monomers styrene and butyl acrylate in the presence of the different CNT types and found that the best monomer conversion and largest particles (in the micron range) occurred with CNTs modified with boron. The insertion of a charge control agent into the polymerized particles was achieved. Monomer conversion of over 90% was realized with all concentrations of MEP-51, whereas conversion was under 70% with all concentrations of MEC-88. Furthermore, analysis with dynamic light scattering and scanning electron microscopy (SEM) indicated that all polymerized particles were in the micron size range, suggesting that our newly developed toner particles were less harmful and environmentally friendly products than those typically and commercially available. The SEM micrographs clearly showed good dispersion and attachment of the CNTs on the polymerized particles (no CNT aggregation was found), which has never been published before.

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Pre- and in-process dimensional compensation in the selective thermoplastic electrophotographic process

Shan,

Yeh,

Hansen

et al. 2024

Int J Adv Manuf Technol

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As a cutting-edge additive manufacturing (AM) technology, the selective thermoplastic electrophotographic process (STEP) has opened up possibilities for mass production with its combination of real engineering plastics and potential high part quality. To improve the accuracy and fidelity of STEP for the most demanding applications, this paper proposes a novel method encompassing both pre-processing and in-process dimensional compensations. Iterative compensation before production is achieved through physics-driven simulation, resulting in input masks that better match the required dimensions at the design level. Layer-wise compensation is implemented during the production process through the laser profiler system, thereby suppressing the accumulation of surface unevenness during printing. With the compensation method proposed in this paper, the maximum distortion during simulated printing is decreased by 86.2%, and surface unevenness is effectively controlled during the printing process.

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Enabling triboelectric charging as a powder charging method for electrophotographic powder application in laser-based powder bed fusion of polymers by triboelectric charge control

Cited by 3 publications

References 46 publications

Innovative Process Strategies in Powder-Based Multi-Material Additive Manufacturing

Innovative Process Strategies in Powder-Based Multi-Material Additive Manufacturing

Encapsulation of Carbon Nanotubes by Styrene and Butyl Acrylate Particles via Suspension Polymerization for Polymerized Toner Applications

Pre- and in-process dimensional compensation in the selective thermoplastic electrophotographic process

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