What is the purpose of a fillet on a part?

The purpose of a fillet on a part is primarily to eliminate sharp edges. Fillets are rounded or curved transitions between two surfaces or edges, which serve several important functions in the design and manufacturing of parts. By removing sharp edges, fillets help reduce the risk of harm during handling, assembly, and operation. They also minimize stress concentration points, which can lead to failure in a part, especially under load or mechanical stress.

In addition to safety benefits, fillets can help improve the overall strength and durability of a component by allowing for more even distribution of stresses. This design feature can lead to enhanced performance and longevity in components that are subject to dynamic loading or oscillation.

While there are other functions that features on a part may serve, such as enhancing material removal, improving thermal conductivity, or creating decorative elements, the primary and most significant purpose of a fillet is to smooth sharp transitions and enhance safety and performance in the part's operational environment.