Research On WIP Control In M Company Based On Lean Production

Multi-variety and small-batch mixed-model assembly line has become the mainstream mode of assembly line nowadays,and the outstanding problem of mixedmodel assembly line is the accumulation of products.In this paper,the research on the WIP control of mixed-model assembly line is based on the lean production concept,which is carried out from four aspects: load balancing,production control system,material distribution and scheme implementation.Firstly,the value stream analysis is carried out on the mixed-model assembly line to reflect the current situation of WIP.Aiming at the unbalance of assembly work load,an optimization model of the mixed-flow assembly line balance is established,and Lingo software is used to solve the model.The original 10 stations are divided into 6 stations,so that the actual takt time of the mixed flow assembly line is less than the theoretical takt time.Then,a production control system is designed to ensure the orderly flow of WIP.After the optimal transmission batch and the optimal production sequence are determined according to the production batch and station cycle time,the advantages and disadvantages of the three production control systems are compared,and the pushpull combined control system is selected as the production control system of the general assembly line,and the improvement is carried out.Kanban pull strategy is adopted upstream of bottleneck station.The main work includes the design of Kanban and Kanban box,the design of Kanban workflow and the determination of buffer WIP quantity.At the downstream of bottleneck station,the main work is to design the WIP sign to avoid WIP backlog.In addition,the Andon system is designed to keep the assembly line consistent and coordinated.Finally,the product control strategy is applied to M company's assembly line,which reduces 80.36% of the WIP,reduces the production cycle from 2.14 days to 0.64 days,and reduces the working area of 280 square meters of the assembly line,improves the overall output and increases the company's efficiency.The research on the control of in-process products broadens the research ideas,and has certain practical significance and reference value for solving the problem of in-process products of mixed-model assembly line with manual work.