ISO 8486-2:2007

Overview

ISO 8486-2:2007 specifies how to determine and designate the grain size distribution of microgrits (F230 to F2000) used in bonded abrasives. The standard covers fused aluminium oxide and silicon carbide microgrits used in manufacturing bonded abrasive products, loose polishing grits, and grits recovered from bonded products. ISO 8486-2 defines a graduated F-series (thirteen microgrits) with median sizes from about 53 µm down to 1.2 µm, and sets the sedimentation-based test procedures and acceptance criteria for each grade.

Key topics and technical requirements

• Scope and definitions: Microgrits are defined as grits with median grain sizes (d50) of 60 µm or less determined by sedimentation.
• Grain size criteria: Three simultaneous criteria govern conformity:
  • maximum permissible theoretical diameter at the 3% (d3) point;
  • median theoretical diameter at the 50% (d50) point (must fall within specified tolerances);
  • minimum attainment at the 80% and 94/95% (d80, d94/95) points.
• Test methods: Primary methods are sedimentation-based:
  • Photosedimentometer methods using Micro‑F‑Mastergrits (mastergrit calibration);
  • US sedimentation tube method and related sedimentation analyses;
  • Examples also include Sedigraph/X‑ray gravitational instruments and Coulter counters (as instrument types to indicate in test designation).
• Calibration and correction: Use of certified Micro‑F‑Mastergrits (MPA Darmstadt certificates) to correct instrument bias - measured d50 differences are algebraically applied to sample results.
• Sample preparation: Dispersion by ultrasonics is recommended.
• Permissible deviations: Tables provide measurement tolerance allowances to account for sampling and instrument variability; these are added to the tabulated limits for compliance.
• Annexes: Informative material includes an electrical resistance method, record forms for sedimentation results, and example data presentation.

Applications and users

ISO 8486-2 is essential for:

• Abrasive manufacturers performing product development and quality control;
• QC and testing laboratories verifying grain size distribution of fused aluminium oxide and silicon carbide microgrits;
• Suppliers and purchasers specifying abrasive grit grades for bonded wheels, belts, and polishing media;
• R&D teams and process engineers optimizing polishing and grinding performance where precise microgrit grading impacts surface finish and process stability.

Using ISO 8486-2 helps ensure consistent abrasive performance, reliable supplier acceptance testing, and traceable particle‑size designation across industrial and polishing applications.

Related standards

• ISO 8486-1 - Bonded abrasives: determination and designation of grain size distribution for macrogrits (F4 to F220).