Recent development in Design For Assembly (DFA) has motivated product designers towards minimizing the number of parts in a product so as to reduce the assembly efforts. Assembly sequence for the reduced number of parts with the modified part topologies may not be possible. Determination of optimal assembly sequence for the modified product by performing assembly sequence planning is highly time consuming and it demands high skilled user intervention. In order to achieve the optimum feasible assembly sequence with less computational time, researchers in the past proposed many methods. In this paper, an attempt is made to generate optimal feasible assembly sequences using DFA concept by considering all the assembly sequence testing criteria from obtained feasible assembly sequences. A simulated annealing technique is used to generate all sets of feasible assembly sequences. The obtained sequences consist n - 1 levels during assembly, which will be reduced by DFA concept. DFA uses functionality of the assembled parts, material of the assembled parts and liaison data of the parts to reduce the number of levels of the assembly by considering the directional changes as the objective function. © Springer Nature Singapore Pte Ltd. 2017.