Process Tolerance is a blueprint specification of a process to describe an unwanted but acceptable deviation from a given dimension of the process. It determines maximum and minimum average magnitudes of possible deviations as well as a maximum standard deviation. The term "process tolerance" is often used in manufacturing when there’s some process or a set of interrelated procedures designated for producing large quantities of products or product components.
The measure of tolerance indicates a process’s capability to be stable and controllable. It’s supposed that when a process is tolerant, there is a higher probability that this process is performed as desired, within acceptable deviations.
There are two common approaches for estimating process tolerance. They’re briefly described below:
- Statistical tolerance. This approach assumes that there’s a scenario for a process to specify requirements for variations while supposing that there’s some centered process serving as the baseline for measuring tolerance of the first process.
- Worst-case tolerance. This approach entails using minimum and maximum average values of variations for a process to determine the worst-case scenario and define the tolerance measure. It actually means that such a scenario brings zero standard deviations, allowing the process to be performed at the extreme level.