“So, what is it that you do, again…?”

Telling someone that you work for a company that develops instrumentation for material characterization, or specifically in my case, for the measurement of particle size, tends to require a bit of explanation. Fortunately, examples of the relevance and importance of particle size analysis are wide and varied.

My usual go-to example, as something that everyone can related to, is chocolate. I explain that the particle size of the chocolate is important, as it governs the mouthfeel of the final product: a smaller particle size will result in a smoother chocolate mouthfeel.

Figure 1: Mmm, chocolate…

When the conversation progresses…

I might then jump to applications within pharmaceuticals: how rapidly your headache subsides is determined by how rapidly the active ingredient in the drug you’ve taken is absorbed into the bloodstream. The dissolution rate of the active ingredient is critical, and is related to its surface area to volume ratio, which in turn is related to its particle size.

Then there are localized applications, such as the characterization of miso paste in Japan. Not too dissimilar to peanut butter, there are coarser and smoother grades of miso paste, with a larger particle size associated with the former and a smaller particle size with the latter. As with my favored chocolate example, in this case particle size is used as an assessment for texture of the final product.

Figure 2: measuring the PSD of miso paste on the Mastersizer 3000

Then we talk powders

Depending on how captivated (or captive…) my audience is, I will highlight the importance of particle size analysis in one of the trendiest areas of manufacturing: 3D printing. With the potential to build complex parts at point of use, 3D printing, or additive manufacturing, has captured the interest of aerospace and medical industries, as well as catching the wider public imagination in recent years. The particle size of the powder feedstock impacts the flowability of the powder. Smaller particles have a tendency to clump together (think icing sugar versus granulated sugar), reducing flowability and spreadability of the powder as it is applied to the powder bed during manufacturing. An inhomogeneous powder bed layer will result in the formation of a part with defects, which is inconsistent to the next part manufactured. However, smaller particles also fill in the gaps between larger particles in a structure, leading to a higher packing density and resulting in the formation of a more dense part. As is so often the case, it is about striking a balance to optimize process efficiency with final product quality.

Figure 3: Additive manufacturing: another application where particle size analysis is critical

In this blog series, we will travel around the world, visiting our network of global particle sizing specialists. They will talk about the various applications of particle sizing, ranging from personal favorites and ones unique to their locality, through to topical examples. We aim to bring you a taste of the wide and varied applications of particle size analysis – enjoy the ride!

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