Free air beam in an electric field for determination of the electrostatic charge of powders between 1 and 200μm

Epping, Reinhold H.; Kuettner, Andreas

doi:10.1016/s0304-3886(01)00210-8

Cited by 7 publications

(5 citation statements)

References 2 publications

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“…Each measurement has been performed three times with several thousand particles detected in each measurement to guarantee statistical relevant data. A more exhaustive description of the concept of the measurement device and its unique selling point, the used free air beam technique, can be found in Epping et al [29].…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2019

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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.

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Section: Methodsmentioning

confidence: 99%

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

et al. 2019

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“…Both polarities can be determined by one measurement. However, the electric field caused by the inhomogeneous geometry leads to a more complex calculation to obtain the particle path through the measurement cell (Epping and Kuettner, 2002). Fig.…”

Section: Charge Distributionmentioning

confidence: 99%

Triboelectric charging of powders: A review

Matsusaka

Maruyama

Matsuyama

et al. 2010

Chemical Engineering Science

499

336

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Particles are often electrostatically charged by frictional contact during powder-handling operations. This phenomenon is called 'triboelectric charging' or 'contact electrification'. The charged particles cause problems such as particle deposition and adhesion. In addition, if particles are excessively charged, an electrostatic discharge may occur, which can pose a risk of fire and explosion hazards; thus, to mitigate the adverse effects, it is important to elucidate the underlying triboelectric charging mechanisms. The electrostatics is, on the other hand, very useful in a number of applications that have been developed using the principles. In this review, the basic concepts and theories of charge transfer between solid surfaces are summarized, and chemical factors depending on materials and environmental effects are described. To theoretically analyze the process of particle charging, relevant models are discussed. Using the models, particle charging by repeated impacts on a wall is formulated. To experimentally evaluate particle charging, measurement and characterization methods are outlined. Furthermore, important applications and computer simulations are described.

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“…The technique has been used to study bipolar charging for micrometre size range particles, and interactions between inhaler surfaces and formulation. However, issues with particle detection and analysis system through the sensing volume may occur due to the electric field caused by inhomogeneous geometry (Epping and Kuettner 2002). Another novel instrument used by Yli-Ojanpera et al 2014, Wong et al (2015) and Leung et al (2016) is Bipolar Charge Analyser (BOLAR TM ).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a new dispersion technique for assessing triboelectric charging of powders

Zafar

Alfano

Ghadiri

2018

International Journal of Pharmaceutics

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In a number of applications, especially in pharmaceutical drug development, there is often a very small powder quantity available for evaluating the manufacturability of new drugs. However, it is highly desirable to be able to quickly evaluate processing issues, and where possible using the smallest powder quantity. In the present work, a proprietary commercial powder dispersion device (the disperser of Malvern© Morphologi G3) is adapted to evaluate the triboelectric charging tendency. A very small powder quantity (as small as 0.1 mg) is dispersed by a pressure pulse of compressed gas such as air or nitrogen. This causes the particles to become air borne and collide with the containing walls, resulting in dispersion and leading to triboelectric charge transfer between the particles and the walls. In this work, the charging propensity of a number of materials is evaluated and the effect of particle surface functional groups on the tribo-electric charge transfer is analysed. Model materials with a well-defined shape (glass ballotini) but with different silane groups deposited on their surfaces as well as a number of organic crystalline particles (such as aspirin, α-lactose monohydrate and paracetamol) are tested. Following dispersion the particles move immediately to a Faraday cup placed directly underneath the disperser. Therefore, particle charge is measured with no decay. The method can differentiate charging of different polymorphs of the same material, different silane groups on the surfaces of glass ballotini and different crystal morphologies obtained from crystallisation from various solvents.

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Free air beam in an electric field for determination of the electrostatic charge of powders between 1 and 200μm

Cited by 7 publications

References 2 publications

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

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

Triboelectric charging of powders: A review

Evaluation of a new dispersion technique for assessing triboelectric charging of powders

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