Kumar Devarajan Manufacturing Engineering Manager, Oliver Manufacturing

Just as farmers look to deploy precision planting practices this spring, seed companies expect precision during the sorting and sizing process that happens post-harvest. Precision during the seed sizing process plays a vital role in agriculture, as research has shown that the germination rate is better for flat kernels compared to that of large and small kernels. Additionally, seed size impacts gravity separation and seed treatments.

For instance, large flat kernels require less air for fluidization compared to large round kernels, and during the seed treatment process, the application rate varies to properly cover flat seed versus round seed and its surface area.

Today, we mostly sort corn into five sizes (large round, medium round, small round, large flat and medium flat). Improvements toequipment and technological advancements allow for both precise and accurate grading — yes, there is a difference. “Accuracy” is how close the measurement conforms to the correct value, while “precision” is how much variation exists within a set of values. For example, if you have a set measurement for flat corn, the flat corn set is precisely sized if all the thickness measurements are close to each other (millimeters), while the flat corn set is accurately sized if the average of all the thickness measurements is close to the true value. It’s about precision and accuracy.

Left – Figure 1: Slotted cylinder with inaccurate and precise orifices Right – Figure 2: Slotted cylinder with accurate and precise orifices

Most companies are able to precision size seed, but the average seed size is not accurate enough to hit the true value of seed thickness or width. For truly proper sizing, we need both accurate and precise grading cylinders, which grade seed thickness to the closest measurement of the true value.

Left – Figure 1: Slotted cylinder with inaccurate and precise orifices Right – Figure 2: Slotted cylinder with accurate and precise orifices

Pictured here are two cylinders: Figure 1 and Figure 2 show how sizing flat corn changes depending upon the cylinder orifice accuracy. Each hole (orifice) has a specific tolerance for each cylinder size. For example, a 13/64 (0.2031) slotted conical cylinder has a tolerance of +0.001” and -0.0035”. Tolerance of each orifice in the cylinder plays a vital role to accurately size the seed.

At Oliver Manufacturing, we engineer the accuracy and precision of each sizing orifice and its corresponding kernel presentation. This starts with tooling that is designed and custom made based on our specifications for each unique sizing requirement. Every orifice is punched and formed independently to ensure repeatable quality for your application.

During each step of our Size Right cylinder manufacturing process, we measure and validate the cylinder’s orifices to meet a 95 percent confidence level — one of the tightest tolerances available in the market. Combine this with our statistically controlled processes to measure and validate the cylinder orifices and we provide the most precise and accurate sizing cylinder.

Precision and accuracy shouldn’t just be left to plant breeders and farmers; it should be evident throughout the value chain, including the seed sizing process.