Method Change
An OpM is randomly chosen and replaced by an option OpM, if there is any. The current operation process for OpM6 is {M1, T3, z}, after randomly choosing an operation process from the obtainable operation pools. The new operation process for OpM6 changes to {M1, T2, z}.
By utilizing the sequence changes, this is clear that such exchanges may conclusion in an invalid sequence since the precedence constraints might be violated. Thus, to satisfy the precedence constraints, the chosen operations or methods will be checked before proceeding to the next step. Or else, this will go back to choose the two swapped operations again. In aforementioned process planning problem, the detailed steps of implementing the SA algorithm is described in Programme no.4.