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Re-inventing the wheel

Situation

The client company had identified an opportunity to produce and market a replacement for wheels and tires in radial irrigation systems. The new product would provide specific benefits by employing drive tread rather than a tire. Cost competitiveness would be a challenge. Even with significant benefits, the typical wheel and tire system were very cost-effective. In order to drive down the per-unit cost of the product, the client company sought to use injection molded plastic parts wherever possible. The system is subject to massive loads from the irrigation system itself as well as from the drive system. The client needed to determine if injection molded plastic was suitable, and help to define the geometry of highly stresses parts. As a smaller company, the client needed to do this without investing in a full internal Research & Development department.

Engineering Analysis Solution

Full engineering analysis, geometry definition, and design optimization for production would all need to be part of this project. With lots of experience in complex analysis, as well as in-house expertise in injection molding, this project was a great fit for our team.

R&D Services Approach

After taking the time to fully understand the application, our R&D services engineers went to work identifying the parts of the system that experience the highest stress. As an initial feasibility check, our engineers defined a rough geometry for those parts and conducted a Finite Element Analysis (FEA) to see how the parts might react to the loads. Early analyses test results showed that the application was pushing the limits of conventional injection molded, glass-filled plastics. The group engaged application engineers from DuPont to see if a custom plastic formulation would help. As the right formulation was identified, the FEA and simulations were revised. The results were positive, and the geometry was then optimized based on the new material as well as manufacturing constraints.

Outcome

The system was successfully designed using a custom formulation. The loads that the drive system endures, pushed the entire drive assembly to the limit. But advanced finite element analysis, simulation, and geometry iteration were used to define designs that will provide reliable service in a critical application.