February 2000

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Particulate Technology Stakeholders Sought to Develop ASTM Particle Sizing Guidelines

A NEW task group has formed to develop standard guidelines for particle sizing procedures within Subcommittee E29.02 on Non-Sieving Methods, part of ASTM Committee E29 on Particle and Spray Characterization.

Calling for broad industry representation, the task group seeks to develop the standard with particle size measurement experts, commercial instrument manufacturers, and industrial users involved in particulate technology, including powder metals, pharmaceuticals, grains, ceramics, cosmetics, cement, etc.

“This standard will provide guidance in choosing the most suitable particle size measurement method and instrumentation for the particular material and particle size range of interest," says Task Group Chairman Frank Venskytis, principal scientist, Physical Testing Laboratory, Osram Sylvania Products Inc., Towanda, Pa. "It will provide some theoretical understanding of the various particle sizing techniques, and the advantages and limitations of each technique.” The proposed standard will be useful for engineers and scientists involved in all particulate technology industries.

Venskytis explains why standard guidelines are needed: “There are numerous methods of particle size measurement, nearly all of them necessarily indirect, measuring different characteristics of particles and relating them to particle size, and therefore defining ‘size’ in different ways. Some guidance is needed for a user to determine which technique is most applicable to his/her material and particle size range.

“Particle sizing is simply a measure of the size of particles in a powder material. Unfortunately, particles in a powder are almost never a single size, nor are they ideally spherical. Therefore, ‘size’ must be defined in terms of equivalent spheres, and a distribution of sizes must be determined. Particle size information is used, for example, in determining pressing and sintering characteristics in metal and ceramic powders, as well as the properties of finished parts consolidated from powders; in determining drug efficacy and delivery; in determining the flow characteristics of particulate materials, including grains in bins or silos; and in assessing applicability of cosmetics and sunblocks. There are many other examples of the use of particle size information.”

Venskytis said the proposed standard will provide a guide to the selection of appropriate particle sizing techniques, and an understanding of the advantages and limitations of the various particle size measurement methods.

To participate on the task group or discuss this activity, contact Frank Venskytis, principal scientist, Physical Testing Laboratory, Osram Sylvania Products Inc., Hawes St., Towanda, PA 18848 (570/268-5339; fax: 570/268-5330). Committee E29 meets Oct. 22-24 during ASTM Committee Week in Orlando, Fla. For meeting or membership details, contact E-29 Staff Manager Jim Olshefsky, ASTM (610/832-9714).