Final answer:
In manufacturing, determining allowances is essential to ensure parts fit and function properly within acceptable variation limits. Allowances relate to tolerance dimensioning as they define the acceptable range of variation that a manufactured part can have, ensuring interchangeability, quality control, and cost-effective production.
Step-by-step explanation:
It is important in manufacturing to determine allowances because they define the limits of acceptable variation in the size of manufactured parts. This is necessary to ensure that parts fit together correctly in assemblies and perform as intended. The allowance is the difference between the basic dimensions and the actual maximum and minimum dimensions a part can have. It is closely related to tolerance dimensioning, which is the numerical value defining the allowable limit of variation for a physical dimension. A dimension with a tolerance specifies the range within which the actual dimension must lie, and allowances are used to determine these tolerances based on how parts will fit together (e.g., clearance fit, interference fit, or transition fit).
Together, allowances and tolerances ensure that parts can be manufactured at reasonable costs while meeting functional and assembly requirements. They are fundamental to quality control, interchangeability, and the economic production of components. Without clear allowances and tolerances, components may not fit together or function properly, leading to increased waste and cost.