Design analysis of the vertical plate type mechanic seed metering unit for some small seeds

Although precision seeders are widely used in Turkey, there is limited research on mechanical vertical plate-type precision seeders. These seeders still face some challenges when seeding small seeds, such as vegetable seeds. Given the high economic value of small seeds and the lack of data on vertical plate seeders, this study aims to analyze the design of a vertical plate mechanical seeder for sorghum and onion seeds. Initially, three different seed slot designs on the seed plate, seed falling point angles, and seed plate rotation speeds were tested in a virtual environment using computer-aided design and simulation programs. Based on the optimum values of the parameters from the simulation tests, the vertical plate seeder was produced and tested for verification in laboratory conditions. Based on the simulation tests, it was concluded that the trapezoidal shape is the most suitable for the seed slot when it comes to sorghum and onion seeds. For both types of seeds, the best performance was observed when the falling point angle on the hopper was set to 120°. Additionally, the optimal uniformity of seed distribution was achieved with a rotation speed of 24 min-1 for sorghum and 12 min-1 for onions. To verify a seeder designed for simulation tests, the same seeder was manufactured and operated with the parameters specified in the simulation tests. In the laboratory experiments, the time between successive seeds was measured, and several parameters such as the mean seed spacings, coefficient of variation of mean seed spacings, multiple index, miss index, and quality of feed index were calculated to determine the seed distribution uniformity of the seed metering device. The laboratory verification tests showed that the coefficient of variation of seed spacing and quality of feed index were 17.3% and 86.03% for sorghum and 12.5% and 89.1% for onion, respectively. The difference between the laboratory and the simulation was less than 10%, confirming that the laboratory experiments validate the simulation experiments.