Tolerance refers to the total allowable error within an item and is specifically represented with the symbol +/-. During the manufacturing process it’s almost inevitable that items on the line can become damaged at one point or another. Products can face damage in multiple ways. For instance, changes in temperature and humidity can cause a product to become warped and disfigured. Warping can also occur if there’s improper feedback from the process control device. No matter the reason, it has become necessary to take any and all errors into consideration during the manufacturing and inspection processes. When used in this manner, tolerance is factored into the equation when the acceptable error range (the range where the quality of the product in question is still intact) is being set. The assumption is that a variation can occur at any given step during the manufacturing process.
Accuracy refers to a measurement’s degree of correctness. When this process is applied to the measurement process, it becomes known as measurement accuracy. Measurement accuracy becomes vital when attempting to ascertain how accurate a result will be. Measurement systems that have a greater measurement of accuracy are capable of performing more accurate measurements.