A binary integer programming model for the simple assembly line balancing problem (SALBP), which is well known as SALBP‐1, was formulated more than 30 years ago. Since then, a number of researchers have extended the model for the variants of assembly line balancing problem. The model is still prevalent nowadays mainly because of the lower and upper bounds on task assignment. These properties avoid significant increase of decision variables. The purpose of this paper is to use an example to show that the model may lead to a confusing solution.
The paper provides a remedial constraint set for the model to rectify the disordered sequence problem.
The paper presents proof that the assembly line balancing model formulated by Patterson and Albracht may lead to a confusing solution.
No one previously has found that the commonly used model is incorrect.
