What does interference refer to in mechanical assembly?

Interference in mechanical assembly refers specifically to the condition where one part overlaps or interferes with another part when they are assembled together. This situation can arise due to various reasons, such as tolerances in manufacturing not being properly adhered to, or when the design does not allow sufficient clearance between parts.

When parts are designed to fit together, engineers must consider the dimensional accuracy and allowances for movement to ensure that components can assemble without obstruction. If there is interference, it can lead to assembly issues, functional problems in the final product, or even damage to the parts involved. This concept is critical in engineering design, ensuring that all assembled components operate smoothly and as intended.

The other options pertain to different aspects of mechanical assembly, such as size, durability, and aesthetic features that do not directly involve the technical relationship of parts when they are assembled together.