Sieve manufacturers produce testing sieves using various sizes of wire cloth, per ASTM International standard E 11, Specification for Wire Cloth and Sieves for Testing Purposes. They also use ASTM standards E 161, Specification for Precision Electroformed Sieves, and E 323, Specification for Perforated-Plate Sieves for Testing Purposes when producing sieves from perforated plate. These specifications require the manufacturers to test the wire cloth or perforated plates using various methods of optical comparison or computer measuring devices that use the same optical principles that measure the size of the openings in the test sieves.
According to Charles Hubbard, chair of ASTM Subcommittee E29.01 on Sieves, Sieving Methods and Screening Media, the method of testing described above works well for manufacturers, but it leaves the users of the sieves unable to test or calibrate them, even though it is a requirement of third-party auditors that users provide procedures on how they calibrate their measuring devices. However, E29.01 has now developed a new standard, E 2427, Test Method for Acceptance of Performance Testing of U.S. Standard Test Sieves, for this purpose. Subcommittee E29.01 is under the jurisdiction of ASTM International Committee E29 on Particle and Spray Characterization.
"With E 2427, users of test sieves are now able to make a standard test reference material that is made out of the same materials that they manufacture," says Hubbard. "By doing this they can now perform a test procedure that compares a sieve that is traceable to national standards to the sieves that they use to test their products." Hubbard further notes that it is not possible to adjust a test sieve, but it is possible to use E 2427 to identify if a test sieve is drifting out of a users tolerance.
Industries concerned with particle sizing, such as abrasives, metal powders, ceramics, cement, soils and sand are most likely to use E 2427, especially if they use standards E 11, E 161 and E 323 to test their products.
Hubbard says that the subcommittee will be working on a precision and bias study for the standard. Anyone interested in participating in the precision and bias work is welcome to get involved.
For further technical information, contact Charles Hubbard, Electro Abrasives Corp., Buffalo, N.Y. (phone: 716/822-2500; firstname.lastname@example.org). Committee E29 will meet April 26-27, in Ft. Lauderdale, Fla. For membership or meeting details, contact Nancy Morrissey, ASTM International (phone: 610/832-9736; email@example.com).