An Investigation into the Compaction of Powders

Train, D.

doi:10.1111/j.2042-7158.1956.tb12206.x

Cited by 151 publications

(38 citation statements)

References 6 publications

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“…Another observation that can be made is that the pattern of increasing local porosity with increasing compact depth is similar for all photo positions. This is in contradiction with results of other authors who found higher densities in the top corners compared to the centre of the top layer (17,18,21). The discrepancy is probably caused by the use of different materials.…”

Section: Photos: Visual Observationcontrasting

confidence: 84%

Location-Dependent Analysis of Porosity and Pore Direction in Tablets

Frijlink

Vliet

et al. 2005

Pharm Res

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Section: Photos: Visual Observationcontrasting

confidence: 84%

Location-Dependent Analysis of Porosity and Pore Direction in Tablets

Frijlink

Vliet

et al. 2005

Pharm Res

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“…This effect may be attributed to the flow of granules being directed towards the centre of the specimen due to movement along the die wall being impeded by friction [Train 1956]. …”

Section: Estimation Of Compressive Stressmentioning

confidence: 99%

“…This phenomenon was first explained by Train [1956], based on the movement of coloured layers within compacted magnesium carbonate powder beds. Similar results have also been obtained in many subsequent studies, using diverse materials and methods.…”

mentioning

confidence: 99%

Using small-angle X-ray scattering to investigate the compaction behaviour of a granulated clay

Laity

Asare-Addo

Sweeney

et al. 2015

Applied Clay Science

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ABSTRACT:The compaction behaviour of a commercial granulated clay (magnesium aluminium smectite, gMgSm) was investigated using macroscopic pressure-density measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray microtomography (XµT) and small-angle X-ray scattering (SAXS). This material was studied as a potential compaction excipient for pharmaceutical tabletting, but also as a model system demonstrating the capabilities of SAXS for investigating compaction in other situations.Bulk compaction measurements showed that the gMgSm was more difficult to compact than polymeric pharmaceutical excipients such as spheronised microcrystalline cellulose (sMCC), corresponding to harder granules. Moreover, in spite of using lubrication (magnesium stearate) on the tooling surfaces, rather high ejection forces were observed, which may cause problems during commercial tabletting, requiring further amelioration. Although the compacted gMgSm specimens were more porous, however, they still exhibited acceptable cohesive strengths, comparable to sMCC. Hence, there may be scope for using granular clay as one component of a tabletting formulation.Following principles established in previous work, SAXS revealed information concerning the intragranular structure of the gMgSm and its response to compaction. The results showed that little compression of the intragranular morphology occurred below a relative density of 0·6, suggesting that granule rearrangements or fragmentation were the dominant mechanisms during this stage. By contrast, granule deformation became considerably more important at higher relative density, which also coincided with a significant increase in the cohesive strength of compacted specimens.Spatially-resolved SAXS data was also used to investigate local variations in compaction behaviour within specimens of different shape. The results revealed the expected patterns of density variations within flat-faced cylindrical specimens. Significant variations in density, the magnitude of compressive strain and principal strain direction were also revealed in the vicinity of a debossed feature (a diametral notch) and within biconvex specimens. The variations in compaction around the debossed notch, with a small region of high Clay compaction SAXS -revised PRL 2015-01-03

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“…Density of compacts can be measured with instrumented compaction unit, which can precisely trace the change of height, therefore density can be determined using known weight of charge. This approach is used in very early studies such as Train (1956) and recent studies such as Michrafy et al (2003). As one of the earliest efforts of using density distribution in powder compaction study, Train (1956) demonstrated that density of compact is not homogeneous and neighbor of a stationary lower punch wall has higher density compared to upper central region.…”

Section: Quality; Density and Density Distributionmentioning

confidence: 99%

“…This approach is used in very early studies such as Train (1956) and recent studies such as Michrafy et al (2003). As one of the earliest efforts of using density distribution in powder compaction study, Train (1956) demonstrated that density of compact is not homogeneous and neighbor of a stationary lower punch wall has higher density compared to upper central region. This difference of density is more pronounced with unlubricated die and attributes to defects of compacts such as capping.…”

Section: Quality; Density and Density Distributionmentioning

confidence: 99%

Critical Review on Engineering Mechanical Quality of Green Compacts using Powder Properties

Pandeya²,

Karamchandani

et al. 2018

KONA

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For processes involving particulate materials, mechanical properties of green compacts are of great interest when they are final or intermediate products. Optimal quality of green compacts is achieved usually with empirical approaches, i.e., unexpected issues in processes or products' quality are usually mitigated by time and resource consuming trial-and-error methods. Issues of the powder compaction are commonly observed when there are problems in feed materials or operational conditions even without any substantial change in a formula. Such divergent behavior of particulate materials is especially problematic for product developments and reliable operations. It has been widely accepted hypothesis that properties of particles are determinants of mechanical behavior of powder during compaction and the quality of resulting compacts. With recent developments in nanotechnology, characterization and engineering of individual particles at a microscopic or sub-microscopic scale are now feasible. Leveraging recent technological advancements, there has been a good progress in regard to quantitative understanding of mechanical relationships between properties of particles, particle system and final product. This review highlights the recent developments and gaps in engineering mechanical quality of powder compacts in conjunction with the characterization of particle systems and compaction at multiple scales.

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An Investigation into the Compaction of Powders

Cited by 151 publications

References 6 publications

Location-Dependent Analysis of Porosity and Pore Direction in Tablets

Location-Dependent Analysis of Porosity and Pore Direction in Tablets

Using small-angle X-ray scattering to investigate the compaction behaviour of a granulated clay

Critical Review on Engineering Mechanical Quality of Green Compacts using Powder Properties

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