An integrated approach for a new flexible multi-product disassembly line balancing problem

Flexible disassembly line design for end-of-life (EOL) products is a key issue in the remanufacturing industry. However, existing studies for disassembly line balancing have not simultaneously considered multiple EOL products, the identical parts of these products and uncertainty during disassembly, which are important characteristics of flexible disassembly lines. The present study addresses a new flexible multi-product disassembly line balancing problem in which (1) disassembly schemes need to be selected, (2) a workstation can disassemble multiple EOL products, (3) identical parts of multiple products can be treated as identical tasks, and (4) only partial probability distribution information of processing times is known. For the problem, an integrated approach is developed, which is composed of a chance-constrained program, a distribution-free model, efficient valid inequalities and an exact lifted cut-and-solve method. Numerical experiments are conducted on an illustrative example, 10 instances based on realistic products and 480 randomly generated instances with up to 20 products, 400 tasks and 86 workstations. Computational results show that the proposed valid inequalities can reduce about 75% computational time of the original model, and the lifted cut-and-solve method needs only 17.53% and 40.65% of the computational times required by the CPLEX and the classic cut-and-solve method, respectively.