An Approach To Cellular Manufacturing Based On Movements And Machine Workload Balance

Cellular manufacturing system(CMS) has very good performance on today’sproduction with small-to-medium volume and diversity, can meet the flexibility andcompetition, so more and more researchers and companies pay attention to it.CMS contains three aspects: cell formation, inter-cell design, intra-cell design. Inthis paper, cell formation and inter-cell design are concerned. For the cell formationproblem, factors like production volume, alternative part routings, process time,operation sequences, machine capacity are considered to built a multi-objective forminimizingmachine workload imbalances and inter-cell and intra-cell part movementssimultaneously. Intra-cell and inter-cell part movements are reflected by the number ofvoids and exceptional elements of the machine-part incidence matrix, thus theoptimization of part movements is converted to minimize the total number of voids andexceptional elements. For the part operation sequences, the phenomenon that inter-cellpart movements would double when a part needs machines in other cells, and it is notthe first and last sequence of the part. For the cell number, a mathematical model whichuses the cell number as the unknownquantity, intra-cell and inter-cell part movements asthe objective, through solving the first derivative to get the best cell number. Forinter-cell design, based on the location information and inter-cell part movements aftersolving the cell formation problem, a model is proposed to minimize the inter-cell partmovements that the cells with large inter-cell part movements assigned adjacently.Genetic algorithm is used to solve the problem, a unique chromosome with threesections is proposed, which refer to the assignments of machines, parts, and selectedrouting for each part respectively. By this way, the three sections can be determined atthe same time.An example is used to verify the proposed model, and the solution is comparedwith other researchers’ work, so that the superiority of the proposed model is testified.At last, the model is used for a company which produces gears for cars, assigningthe machines and parts into cells so that CMS is applied. Then do the inter-cell designfor the solution concluded after solving the cell formation problem. After using CMS, the intra-cell and inter-cell part movements are minimized, the imbalances of machineworkloads are improved.