New particle size measurement technique uses air permeability for greater precision

August 23, 2017

August 23, 2017

New particle size measurement technique uses air permeability for greater precision

The Subsieve AutoSizer (Courtesy Micromeritics Instrument Corporation)


Micromeritics Instrument Corporation’s Particulate Systems Division, Norcoss, Georgia, USA, has announced a new instrument for the more precise estimation of the average particle size of powders. The new instrument uses an air permeability technique previously popularised by the Fisher Sub-Sieve Sizer, which is no longer available.

The Subsieve AutoSizer (SAS) measures the specific surface area of a powder by passing air through a packed powder bed and determining the pressure of the transmitted air by means of calibrated and traceable digital pressure transducers (also used for setting the packing force and input pressure) instead of the water-filled manometer standpipe (or bubble-rate pressure estimate, in the case input pressure) used in older methods. The specific surface area is then easily converted by the instrument to an equivalent spherical particle diameter using geometric and density considerations.

For over fifty years, the refractory metals, ceramics, lighting, other phosphors and pharmaceutical industries have relied on air permeability measurements to estimate the particle size of their materials. Some of these methods offer very imprecise results, leading to a large degree of rework and confusion in those industries. Because of its accurate and precise measurement of pressure by means of pressure transducers, the SAS reportedly provides much greater precision than traditional methods, allowing for appropriate particle size specifications to be set for both process and quality control, and for outgoing powder material specifications. The new instrument thus offers a fast and easily-obtained estimate of particle size in order to meet those specifications.

Several international standard test methods have been developed for use with the SAS, including ASTM Standard Test Methods B330 (for metals), C721 (for some ceramic materials) and E2980 (a general standard for particle size measurement of a wide range of materials). ISO Standard 10070, a general standard test method for this type of particle size measurement, is currently being revised for use with the SAS.

August 23, 2017

About Metal Additive Manufacturing magazine

Metal AM magazine, published quarterly in digital and print formats, is read by a rapidly expanding international audience.

Our audience includes component manufacturers, end-users, materials and equipment suppliers, analysts, researchers and more.

In addition to providing extensive industry news coverage, Metal AM magazine is known for exclusive, in-depth articles and technical reports.

Our focus is the entire metal AM process from design to application.

Each issue is available as an easy-to-navigate digital edition and a high-quality print publication.

In the latest issue of Metal AM magazine

Download PDF

Extensive AM industry news coverage, as well as the following exclusive deep-dive articles:

  • BMW Group: Laying the foundations for the application of metal Additive Manufacturing in the automotive industry
  • Predicting the metal Additive Manufacturing market – and breaking the hype cycle
  • China’s thriving metal Additive Manufacturing industry: An outsider’s perspective
  • Enhancing the productivity of Additive Manufacturing facilities through PBF-LB automation
  • Award-winning metal AM parts from the MPIF’s 2024 Design Excellence Awards
  • Performance of eddy currents for the in-situ detection of defects during PBF-LB metal AM

The world of metal AM to your inbox

Don't miss any new issue of Metal AM magazine, and get the latest industry news. Sign up to our twice weekly newsletter.

Sign up

Looking for AM machines, metal powders or part manufacturing services?

Discover suppliers of these and more in our comprehensive advertisers’ index and buyer’s guide, available in the back of Metal AM magazine.

  • AM machines
  • Process monitoring & calibration
  • Heat treatment & sintering
  • HIP systems & services
  • Pre- & post-processing technology
  • Powders, powder production and analysis
  • Part manufacturers
  • Consulting, training & market data
View online

Discover our magazine archive…

The free to access Metal Additive Manufacturing magazine archive offers unparalleled insight into the world of metal Additive Manufacturing from a commercial and technological perspective through:

  • Reports on visits to leading metal AM part manufacturers and industry suppliers
  • Articles on technology and application trends
  • Information on materials developments
  • Reviews of key technical presentations from the international conference circuit
  • International industry news

All past issues are available to download as free PDFs or view in your browser.

Browse the archive

Share via
Copy link
Powered by Social Snap