Bead-mill trial / Acceptance method
A Hegman or micron grind-gauge reading cannot be converted universally into D50 or D90. Its micrometre value is the groove-depth scale at the method-defined trace observation, not a directly measured particle diameter. Laser diffraction reports a model-based particle-size distribution. Choose the release method from the product risk and keep its complete test basis attached.
Keep the measurands separate
The same sample can produce a grind-gauge result and a particle-size distribution, but the numbers do not describe the same part of the material in the same way.
ISO 1524 and ASTM D1210 frame gauge methods for fineness or degree of dispersion in paints, inks or pigment-vehicle systems. Record the applicable material, gauge, scale and reading rule; do not report the result as D50, D90 or a complete particle-size distribution.
For ISO 13320 laser diffraction, retain the distribution weighting, sample preparation, instrument, optical model and reporting basis. Its equivalent-sphere volumetric distribution does not create a material-specific acceptance limit.
Paired results from the same formulation, sample plan and controlled laboratory methods may support a local correlation. Keep that record specific to its material and methods, and never use it as a universal Hegman-to-D50 or Hegman-to-D90 conversion.
Trial-release route
The buyer, responsible laboratory and equipment supplier should agree what failure the method is meant to detect, then preserve that basis from the first sample through disposition.
State whether the acceptance concern is visible coarse particles or agglomerates, surface smoothness, a weighted size distribution, a rare oversize fraction or another product property.
Check the current method scope against the actual material. ISO 1524 excludes products containing flake-form pigments, so the standard name alone cannot release every coating, ink or slurry.
Record the approved sampling point, sample identity, process stage, time, temperature, conditioning, instrument or gauge, operator or laboratory, repeats and raw observations. This page does not instruct anyone to open, reach into or bypass guards on operating equipment.
For every selected method, state the result expression, limit or comparison basis, repeat and variability rule, retest trigger, approval owner and disposition. Do not fill a missing method with a converted value.
Endpoint-method checklist
Use only methods technically approved for the material and product risk. The fields below organize an acceptance record; they do not establish a JINPIONEER result.
Open the process briefProduct or controlled formulation reference, lot, process stage and the defect or quality condition the endpoint must detect.
Approved sampling point and safe procedure owner, sample time and quantity, mixing or splitting, temperature, hold history and sample identity.
Applicable standard and edition, gauge type and range, Hegman or micron scale, cleanliness and condition, draw and reading rule, operator and repeats.
Method and edition, weighting, preparation and dispersant, instrument and accessory, optical model and inputs, concentration, repeats and report revision.
Material exclusions, flake-form pigments, color or contrast limits, viscosity or flow concerns, agglomeration state and any laboratory qualification note.
If both methods are used, identify the same-batch samples, independent results, variability and the exact material, laboratory and method scope of any correlation.
Separate acceptance row for each method, limit or reference comparison, summary statistic, retest trigger, approval owner and nonconforming-material disposition.
Oversize or coarse-tail control and any color, gloss, viscosity, stability, contamination or operating condition that must pass independently.
Draft source record / Pending technical review
These sources distinguish fineness-of-grind testing, particle-size-distribution measurement and safe equipment access. Their cited scopes do not select a trial endpoint for a specific formulation.
Buyer decision FAQ
No universal conversion is valid. A grind gauge records a fineness-of-grind observation under its method, while D50 and D90 are percentiles from a defined size distribution. A material- and method-specific paired study may support local correlation, but the two results remain separate acceptance records.
No. The micrometre reading identifies the groove-depth scale at the observation point defined by the selected method. It is not a direct measurement of an individual particle diameter or a particle-size distribution.
Use the method that detects the buyer's defined product risk and is applicable to the material. Some projects may require a grind-gauge endpoint, some a particle-size distribution, and some both. Agree the method, sample, repeat and disposition rules before the trial.
No. Each method has a sampling and detection boundary, and D90 is not a maximum. If rare oversize material matters, add an independently suitable coarse-tail method, sampling plan and disposition rule.
No. Use only the plant's approved sampling point and procedure under the responsible safety system. Do not open equipment, reach into danger zones, defeat guards or improvise access from this guide.