Computer-Aided Analytical Design of a Ridge Plastering Attachment to Power Tiller

Abstract

Aim: To develop and theoretically validate a ridge plastering machine compatible with power tillers (6-12 hp) to mechanize bund preparation operations like trimming, plastering, and compaction in smallholder paddy fields. The aim is to provide a low-cost, locally manufacturable alternative to expensive tractor-mounted machinery, catering especially to small and marginal farmers in regions like Kerala. Study Design: Analytical design and simulation-based validation study. Place and Duration of Study: Department of Farm Machinery and Power Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, Malappuram, Kerala, India; during the academic year 2021-2022. Methodology: The design was developed analytically and modeled using SolidWorks. A 9 hp KAMCO KMB 200 power tiller served as the prime mover. Speed was reduced from 315 rpm to 215 rpm by modifying the auxiliary gearbox with a 34-tooth gear. Torque at 2000 rpm was calculated as 33.43 Nm, confirming safe operation under maximum load. Gears (21 and 34 teeth, module 3 mm) were designed using Lewis and Buckingham equations and validated for bending stress, contact stress (1331.10 N/mm²), dynamic load (10.44 kN), and wear load (10.66 kN). Shafts, splines, and chain drives were sized with safety factors above 4.0. The functional units-trimming, plastering, and compacting - used twisted blades, plastering discs, and rollers mounted on a square pipe frame. All validations were computational; no prototype was fabricated. Results: Theoretical calculations confirmed that the transmission system, shafting, and ridge-forming assemblies can safely operate under expected field conditions. Design validation via CAD modeling demonstrated feasibility of operation, alignment, and motion paths. The unit was shown to theoretically perform bund trimming, plastering, and compaction in a single pass. Structural elements, material specifications, and torque transmission systems were confirmed to be within safe design limits for use with 6-12 hp power tillers. Conclusion: The proposed design offers a viable, low-cost, power tiller-driven alternative for ridge plastering in smallholder paddy systems. The theoretical validation confirms mechanical feasibility; however, physical prototyping and field trials are needed to evaluate actual performance. Once developed, this machine could reduce labor, cost, and time significantly, thus promoting mechanization and sustainable productivity in small farms.