Description of Tests
and Testing Procedures
To guarantee optimum Quality Control in producing consistent materials throughout the line, LANDS Superabrasives has developed a standard testing procedure that involves continuous monitoring of the vital variables. This testing procedure is one of the cornerstones of our Quality Control Program.
In the following paragraphs LANDS Superabrasives presents some of the standard tests used in the Quality Control Maintenance of the product line.
FRIABILITY TEST. TOUGHNESS INDEX:
Test Objective:
The main purpose of this test is to determine the relative strength of the diamond particles. The core of this test is to determine the particle size after the material is subjected to controlled crushing.
Result:
A Toughness Index is generated by using a formula which relates the various factors of time, crushing procedure and final particle size.
Test Procedure:
First the diamond is sieved and measured. The sample is then subjected to controlled crushing in a mill using hardened steel balls. The vibration, movement and amplitude of this process is fully controlled. After a defined time, the diamond is collected and measured again. There is a direct correlation between the spread in residue sizes after crushing and crystal strength. In general, the coarser and larger the residue, the stronger the original crystal; the finer and smaller the residue, the weaker the original crystal
FRIABILITY TEST AFTER THERMAL IMPACT. THERMAL TOUGHNESS INDEX:
Test Objective:
To determine the thermal stability of diamond products.
Result:
A Thermal Toughness Index is generated by using a formula which relates the various factors of time, crushing procedures and final particle size. The higher the value of the TTI, the stronger the crystal.
Test Procedure:
This test is the same as described above, however the diamond is first heated to 1125°C. in a controlled nonoxygen atmosphere.
Heating may cause the crystal to break up or to damage the surface, edges, and the faces. Strong crystals will yield lower percentages of fine sizes while weaker crystals yield relatively higher percentages of fine sizes.
BULK DENSITY:
Test Objective:
To determine the density of the material.
Result:
Bulk density provides a relationship between the average shape, smoothness of the crystals and specific weights.
Test Procedure:
The bulk density is determined by the weighing the amount of material required to fill a predetermined volume. (Similar to 1 kg of water fills exactly 1 Liter.)
SIZE ANALYSIS. SIEVING INDEX:
Test Objective:
To determine the density of the material.
Test Procedure:
All Mesh powders are sieved according to the latest ASTM/FEPA standard sieving procedures using electroformed sieves (ANSI B74.16, FEPA and ISO 6106).
All Micron powders are obtained by sedimentation, elutriation, and other sizing techniques resulting in micron products according to (and exceeding) the latest ANSI/ISO standards (ANSI B74.20).
In LANDS’s Quality Control Laboratory proprietary Image Pro Analysis equipment is used for micron powders over 2 micron.
For smaller microns, the laser diffraction technology of Malvern testing equipment (Mastersizer 3000) is being used.
COLOR INDEX:
Test Objective:
To determine the color of diamond particles to ensure color consistency of diamond. specimens.
Test Procedure:
A light diffractometer determines the exact color of all diamond specimens.
Result:
By setting color range standards, LANDS guarantees color consistency for each and every product. If the specimens are not within the range of tolerances, batches are rejected.
MORPHOLOGICAL SPREAD:
Test Objective:
To determine the shape of diamond crystals.
Test Procedure:
Diamond crystals are put on vibrating tables, which result in the separation of the material into various batches of crystals having a similar shape. Each shape is assigned a relative index value that indicates the overall particle shape of the sample.
Result:
A range of classes of products, wherein each class of crystals is graded so that a uniform and consistent product is guaranteed.
VISUAL ASPECTS:
Test Objective:
To determine various visual appearances.
Test Procedure:
The diamond is checked under a stereomicroscope with different illuminations (light intensities). Shape, structure, color, and degree of inclusions are examined.
LANDS issues histograms upon request, showing the distribution of particles in the powders, measuring median and Cumulative Distributions.
In addition to the above tests, LANDS Superabrasives administers a variety of other proprietary tests on the aspects of diamond properties such as Impact Resistance, Fatigue Resistance and Crystal purity.