Research On The Two-dimensional Cutting Stock Problem Of Multitype Logs

Cutting stock problems exist in industrial production.They have been got quite a lot of attention and research since long time ago,but these studies mainly focus on general cutting stock problems,such as rectangular cutting problem and so on.With the development of the economy,some special requirements of cutting stock problems began to be concerned.And these problems mainly exist in some special industry or in the part of the enterprise in the industry,such as paper cutting stock problem,silicon steel cutting stock problem and so on.This paper studies the cutting stock problem of log which is also a kind of special cutting stock problems.Cutting stock problem of log exists in the furniture manufacturing industry.Because the forest resources are less and less,the price of log is rising fast and becoming more expensive.Improving the utilization of wood will be conducive to help the company to reduce cost.The main research work in this paper is as follows:(1)For the sake of general single pattern,log should be divided into the middle area and the four sides area.These two parts are based on the two-dimensional layout problem with constraint.The single layout diagram is composed of homogeneous stripe splicing.The pattern of middle area can be got by solving common knapsack problem.And the pattern of other four areas can be got by solving special two-dimensional knapsack problem.By solving the knapsack problem,we get a higher quality layout.(2)The frame of two-dimensional log cutting stock problem is composed of sequential heuristic algorithms,value correction algorithm and the knapsack problem method.The pattern is generated sequentially.The value of the blank would be adjusted after each pattern is generated in order to produce more different pattern.Multiple cutting plans are generated through iteration and the best one will be selected.To verify the validity of the algorithm,this algorithm compares with the intelligent algorithm in the literature,and experimental results show that this algorithm can reduce the loss rate of logs.(3)The number of logs' veer is limited and the cutting process can be simplified.The direction of the stripe can be divided into horizontal and vertical directions in the cutting process.If the stitching is horrizontal stripe and vertical appear alternately,workers should turn over the direction of log frequently.That will be increase the complexity of cutting log,if we can limit the number of bands appear alternately,that can greatly simplify the difficulty of cutting process and make workers work efficiency.Limiting the number of logs' veer can improve the degree of automation and reduce the cost of production.To verify the validity of the algorithm,this algorithm compares with the situation of not restricting the number of logs'veer.