Most particle size measurement technology methods are based on the assumption of spherical shaped particles. This hypothesis leads to significant errors in the analysis if the particles are flake or rod-shaped. Especially for such highly form-anisotropic particles, automated imaging provides an excellent alternative for the determination of tailor-made size specifications.
Realistic proportional values also at the edges of the size distribution, i. e. detection of oversized particles or fine particles
Visual assessment of the dispersing state of a sample (dispersing quality, presence of agglomerates)
Automated imaging methods for the determination of the particle size distribution of a material offers a fundamental advantage over alternative methods such as static light scattering, sedimentation or sieving: Each particle is photographed individually! This results in several important advantages for the determination of the particle size distribution:
Calculation of meaningful size parameters, e. g. geodetic length or Feret diameter for fibres, depending on the application
Selection of the appropriate distribution type (volume, number) depending on the particular task
In addition, the individual photography of the particles gives the opportunity to make statistical calculations on the particle shape, which in practice enables further differentiation of materials. For example, form anisotropy, the deviation of the particles from the ideal sphere, often plays a decisive role for their application and further processing – for example, the conveyance or compaction of powders, the influence on the rheology in dispersions or, in addition to the particle size distribution, the roughness of the particle surface plays an important role for the success of shaping or polishing.
The necessity for tailor-made particle size and shape parameters, combined with ever-increasing PC processing power, ensures that automated imaging methods are becoming increasingly more relevant to a market which is 95% non-spherical..