Sheet metal machining is a commonly used industrial product machining technology, which often includes a variety of methods, such as cutting and blanking, bending, and forming. In these sheet metal machining processes, errors are unavoidable. Errors are allowed but have a range. If the error is beyond the range, it should be caused by improper operation. But what we need to do is to control this error to the minimum to the allowable range. So how do reduce errors in sheet metal machining?