Research On Sequencing Problem For Multi-workshop Based On Sorting Buffers

There are universally all kinds of sorting buffers: selectivity bank, offline buffer, free-access buffer, ring-shaped buffer, etc. in the mixed-model assembly. Because selectivity bank and offline buffer have prominent advantages: low costs, easy maintenance and easy manipulation, they are widely employed in the automobile company. With the background of multi-workshop (multiple assembly line) manufacture, this dissertation studies further two kinds of typical sequencing problems based on selectivity bank & offline buffer.For multi-workshop association sequencing based on selectivity bank, firstly an optimized model is established, the objective of optimization is minimizing the adding-power average of changeovers in the paint shop and setup cost in the assembly shop. Then a composite algorithm is given, which is composed of two level algorithms. The outer heuristic algorithm dynamic adjusts the sequencing of upstream shop; on the other hand the internal a composite algorithm (Genetic algorithm and heuristic algorithm) is employed in selecting a lane to push a product into and heuristic algorithm is selecting a lane to fetch a product from. Lastly, through calculating the example , the algorithm proves effective in practice.For multi-workshop association sequencing based on offline bank, firstly an optimized model is also established. According to the complex constraints of offline buffer's sequencing problem, a new composite algorithm is provided, the outer of which adopts Genetic algorithm, chromosome denotes the sequencing of upstream shop and the inner of which adopts heuristic algorithm to control passing in and out the buffer. Numerical calculations indicate that this algorithm is very efficient to solve the problem in an easy way.After discussing the two kinds of problems, compare the results which selectivity bank and offline bank have influence on the multi-workshop association sequencing, the comparison result indicates offline buffer is more practicality than selectivity bank in the small scale sequencing problem.Finally, the multi-workshop association sequencing algorithm based on sorting selectivity bank and offline buffers is carried out in the manufacturing execution system for automobile mixed-model assembly in Anhui Jianghuai Automobile Co-operation(JAC). The practical application shows that the algorithms provided above improve the efficient of mixed-model assembly, reduce the cost of reduce production cost and improve the throughput of the company.