A part is considered a reject when?

A part is considered a reject when the dimensions are out of tolerance because this indicates that it does not meet the specified requirements necessary for proper functionality and fit within the intended assembly or application. Tolerance is a critical aspect in manufacturing, as it defines the allowable variation in measurements. When a part exceeds these tolerances, it can lead to significant issues such as poor performance, incompatibility with other components, or failure during operation.

In contrast, while aesthetic issues, weight, or finishing requirements may have implications for the part's usability or consumer appeal, they do not directly affect the fundamental ability of the part to function within its intended purpose as defined by engineering specifications. Therefore, non-compliance with dimensional tolerances is the primary reason for classification as a reject.