Abstract:

Objective: In order to solve wooden furniture production line of machine-group layout under multi-product and small lot-size production is prone to create bottlenecks, then resulting in low productivity, we study how to determine the bottleneck and improve the production efficiency in this paper, and through the actual production line to verify the validity and feasibility of the scheduling scheme, the consistence of actual production results and the simulation results are also compared. This paper establishes a model of cluster layout production line with FlexSim. This model trends to save the actual running cost of wooden furniture production line, and it also can be used as a reference for improving the efficiency of other wooden furniture production lines. Method: Taking a cluster layout wooden furniture production line for an example, by setting parameters of source, processor, storage area, transport and other entities according to production hours, transportation hours, production batch and order plan of each order, the model with FlexSim is simulated. Through analyzing simulation results, namely the average process rate and release rate of each process, we can identify the bottleneck process in production line, set time buffer for production system and schedule the orders according SPT (shortest processing time) rule. Result: We can get the state parameters of each working procedure in production line by FlexSim simulation, in which the average process rate of blanking process, milling process, sanding process, assembling process, painting process and testing process is 45.30%, 62.70%, 74.13%, 52.80%, 54.53% and 54.20%, and the release rate of these processes is 42.00%, 57.50%, 72.40%, 22.70%, 30.90% and 29.90%, respectively. Therefore, the average process rate of sanding process is the highest, at 74.13%, and the release rate of sanding process is the highest too, at 72.40%, so the sanding process is the bottleneck of the wooden furniture production line. According to time buffer calculation model, the bottleneck time buffer of each order is 24 min, 31.5 min, 30 min and 36 min, the delivery time buffer of each order is 30 min, 54 min, 54 min and 72 min. Through simulation by FlexSim, we can get that the average process rate of SPT scheme is 90.28%, which increases 16.15% compared with the original plan. By comparing the results of the actual operation and the simulation results, the average processing rate and the average idle rate error of each process are within the range of ±5%. Conclusion: This paper investigates a cluster layout wooden furniture production line model with FlexSim7.lnk, and it can effectively identify the bottleneck of the production line and predict the production results. The bottleneck process might be eliminated by setting the production line time buffer, and a fine schedule according to SPT rule could greatly improve production efficiency of the wooden furniture production line.

Key words: cluster layout, FlexSim7.1nk, bottleneck, simulation, SPT