Fineness of grind gauges – SAGR

The fineness of grind gauges are used to check the fineness of grind and degree of dispersion of solid materials in liquids, pastes and dispersions. They are suitable for detecting coarse particles, agglomerates or residues that have not dispersed correctly in paints, pigments, printing inks, coatings and other fluid or paste-like materials.

A fineness of grind gauge is particularly useful in processes where dispersion quality affects the appearance, stability and performance of the final material. Inadequate grinding or the presence of undispersed particles can cause visible defects, lack of uniformity, application issues or changes in material behaviour during use.

The operating principle is based on a metal block with one or more grooves of progressively varying depth. The sample is spread along the groove using a scraper; by observing the point at which visible particles or agglomerates appear, it is possible to determine the fineness of grind according to the scale on the instrument.

The result can be expressed in microns or on the Hegman scale. The Hegman scale ranges from 0 to 8: higher Hegman values correspond to finer detected particles and therefore to a finer dispersion. This dual reading makes the fineness of grind gauge suitable for laboratories and production checks operating with different methods or specifications.

It is important to distinguish a fineness of grind gauge from a particle size analyser. A fineness of grind gauge does not provide a complete particle size distribution and does not determine the size of all particles in the sample. Instead, it identifies the fineness of grind and the presence of coarse particles or agglomerates in the dispersion, providing a quick and practical check on the grinding or mixing process.

The SAGR fineness of grind gauges are used in quality control and product development for paints, printing inks, pigments, pastes, resins, coatings, plastic products, paper, ceramics, pharmaceutical and food applications, as well as in other sectors where the dispersion of solid particles is a relevant parameter.

Different configurations are available according to the required inspection and reading method. Single-channel models are suitable for standard fineness of grind checks; double-channel models allow comparative checks or parallel readings; wide-channel models provide a larger reading surface, useful when the sample or type of dispersion requires greater visibility during evaluation.

The range includes different measuring ranges, allowing the most suitable instrument to be selected according to the expected fineness of the material to be checked. Model selection depends on the material, required scale, test method and level of process control needed.

SAGR fineness of grind gauges are used for testing in accordance with ISO 1524, ASTM D1210 and ASTM D1316, technical references for determining the fineness of grind and dispersion of systems containing solid particles. The applicable method should be selected according to the material, sector and required control specification.

A calibration report is available on request, useful when the instrument must be included in a quality-control system with documented records of metrological checks.

Fineness of grind gauges therefore provide a simple and direct solution for checking dispersion quality, verifying grinding effectiveness and detecting coarse particles before they can cause defects in the finished material.

Applications

• Fineness of grind checks on paints and coatings
• Verification of the degree of dispersion of pigments and pastes
• Quality control on printing inks and colouring products
• Detection of coarse particles or agglomerates in dispersions
• Verification of grinding in production processes
• Inspection of fluid or paste-like materials containing solid particles
• Readings in microns or on the Hegman scale
• Checks with single-channel, double-channel or wide-channel fineness of grind gauges
• Applications in paints, plastics, paper, ceramics, pharmaceutical and food sectors
• Testing in accordance with ISO 1524, ASTM D1210 and ASTM D1316

FAQ – Fineness of grind gauges

What is a fineness of grind gauge used for?
It is used to check the fineness of grind and degree of dispersion of solid particles in paints, printing inks, pigments, pastes, coatings and other fluid or paste-like materials.

What does a fineness of grind gauge measure?
It helps identify coarse particles or agglomerates in a dispersion and express the result in microns or on the Hegman scale.

Is a fineness of grind gauge a particle size analyser?
No. A fineness of grind gauge does not measure the complete particle size distribution of the sample. It is used to check fineness of grind and detect coarse particles or agglomerates in a dispersion.

How does a fineness of grind test work?
The sample is spread along a groove with progressively varying depth. The point at which visible particles or agglomerates appear determines the fineness of grind according to the instrument scale.

What is the Hegman scale?
The Hegman scale is used to indicate fineness of dispersion. It ranges from 0 to 8: higher values indicate finer particles and a finer dispersion.

When is a reading in microns used?
A reading in microns is used when the indicative size of particles or agglomerates detected in the dispersion must be expressed directly, according to the measuring range of the fineness of grind gauge.

What is the difference between a single-channel and double-channel fineness of grind gauge?
A single-channel model is suitable for standard checks, while a double-channel model allows comparative inspections or parallel readings on the same type of sample.

When should a wide-channel fineness of grind gauge be selected?
A wide-channel model is useful when a larger reading surface is required, for example on dispersions where visual assessment of the sample needs greater visibility.

In which sectors are fineness of grind gauges used?
They are used in paints, pigments, printing inks, coatings, plastics, paper, ceramics, pharmaceutical and food applications, as well as in all processes where solid-particle dispersion must be checked.

Which standards do SAGR fineness of grind gauges refer to?
SAGR fineness of grind gauges are used for testing in accordance with ISO 1524, ASTM D1210 and ASTM D1316.

Is a calibration report available?
Yes. A calibration report is available on request.