Vibratory Compaction: II, Compaction of Angular Shapes

Ayer, J.E.; Soppet, F. E.

doi:10.1111/j.1151-2916.1966.tb13235.x

Cited by 29 publications

(17 citation statements)

References 4 publications

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“…lead to the fact that a powder particle size of less than 30-300 ~m [30] does not have any influence on the effect of vibropacking.…”

mentioning

confidence: 94%

“…Packing using method I does not provide transportable strength of the material but its uniformity in density is very high, except for the outer layers, which may be loose. This may be explained by the fact that the directed structural deformation of the lower layers of the powder blank i in the die 2 during its harmonic oscillations on the elastic suspension 3 are provided by the action on them of the above located layers while the vertical back-and-forth movement of the very top layers is limited by nothing [30]. Nevertheless in view of the advantages stated and the design simplicity method I is widely used [7,31].…”

mentioning

confidence: 98%

“…Some works recommend the use of small amplitudes and high frequencies in packing fine and multifraction powders while others, on the other hand, recommend large amplitudes and low frequencies for coarser powders within the limits of the optimum range of acceleration In determining the optimum conditions of vibropacking, accelerations within the limits of 2-8g with f = 50 Hz and a = 1.0 mm are preferred [7,15,30,34,37]. The use of a > imm promotes processes of separation and loosening of the masses being packed and its optimum value under otherwise similar conditions depends upon the height and the dissipative properties of the powder being packed [16].…”

mentioning

confidence: 99%

“…It has been shown [29] that the direction of oscillations (vertical or horizontal) is not of significance for the effectiveness of the process. The ineffectiveness of circular (undirected) oscillations has been noted [9], and the majority of authors reco~end vertically directed oscillations, sometimes with the use of a small horizontal component [30]. The technical characteristics of the majority of standard vibration units allow the presence of a 10% component of oscillations in a plane perpendicular to the basic one [15].…”

mentioning

confidence: 99%

“…In vibropressing the use of a load and its rational accomplishment are especially important [18,34]. There is information on the effectiveness of its use after preliminary free vibropacking [8] and also on its specific role in vibropacking of multifraction mixtures by the method of "sifting" the fine fraction into the coarse [7,17,30]. Let us turn our attention to methods of charging the powder into the mold: single or layer-by-layer and into a vibrating mold or into a stationary one.…”

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confidence: 99%

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Vibrovacuum packing of powder masses

Degtyareva

Grinberg

1982

Refractories

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In recent years there has been wider and wider development of isostatic pressing of large complex-shaped parts, a disadvantage of which is the necessity of machining of the parts in connection with significant deviations from their specified shape and dimensions. Therefore, preliminary preparation of the material before isostatic pressing acquires great value.The use of vibration actionsto accomplish or activate certain production operations is very effective. Vibration is widely used in the preparation of concrete and formation of parts from it, in processes of dispersing and granulating materials, in ramming posts and shunts and removal of them from the ground, for movement and mixing of loose materials, in heat and mass exchange process, etc.Vibropressing with the application of significant external forces is used as a selfcontained forming method. The action of vibration with the application of comparatively small (up to 0.15 MPa) external forces (overloading) insufficient to obtain a strong and dense raw material may be used as a preliminary operation before subsequent static or isostatic pressing [1][2][3][4][5][6][7][8]. The combination of vibrovacuum packing and isostatic pressing provides uniform density and accuracy in shape and dimensions of parts.There are publications on the first domestic investigations of vibropressing of parts from dispersed refractory materials [9], of Dinas parts with a specified thermal conductivity [i0], and of large magnesite blocks [ii]. Vibropressing of thermal insulation parts [12][13][14][15][16][17][18][19][20][21][22][23][24] and concrete [13, 14] has been described. In the post-war years the investigation and production introduction of vibropressing of refractory parts and also developments of special equipment have been accomplished by the All~Union Refractory Institute [25][26][27][28].Investigations of methods of vibropressing of dispersed materials is inseparably linked with the development of powder metallurgy technology, dry concreting, and the use of a vibroboiling bed [15][16][17][18][19][20][21][22] but until the present time systematic scientific developments of technologies related to vibration processes, other than the vibrotransportation process [23], have been lacking. This may be explained by the great difficulty in a satisfactory, without substantial limitations, mathematical description of a dispersed system during vibropacking, in which the change in the very parameters characterizing this system occur nonlinearally [22]. The final condition of such a system depends both upon factors related to the properties of the powder masses being packed and the form and dimensions of the parts being pressed and upon the conditions of vibropacking.Powders are characterized by the degree of dispersion, the grain size composition, the form of the grains and their hardness (brittleness), the moisture content, the fluidity, the composition and content of the temporary (production) binder, and its distribution. These properties of the powder depend upon the method of...

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“…lead to the fact that a powder particle size of less than 30-300 ~m [30] does not have any influence on the effect of vibropacking.…”

mentioning

confidence: 94%

mentioning

confidence: 98%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%