Understanding Particle Size Measurement Techniques for Improved Blending and Segregation Models and Predictions
Particle size and size distributions are an important piece of information for modeling and predicting powder blending and segregation, as well as in-process quality control and quality assurance. Particle size and size distributions also give insight into the small physical details of a powder in a manufacturing process. These details can contribute to potential desired and undesired products. With recent technological advances, particles are now measured using various analytical techniques and instrumentation. Different analytical techniques seldom provide the same value for particle size. These differences can be advantageous in predicting powder behavior if the data is interpreted properly based on the understanding of the technique used to determine the size. A survey of six different particle size techniques are discussed and compared, including:
• dynamic image analysis (DIA) • sedimentation • static light-scattering (laser diffraction) • electric sensing zone (ESZ) • air permeability • dynamic light scattering (DLS)
The result of the comparison is that particle size data is heavily influenced by shape and the technique used to measure it. Each technique measures a different property of the particles and converts the data into a size. For predictive modeling, a combination of techniques may be needed.