MATHEMATICAL MODEL AND EXPERIENCE OF IMPLEMENTATION OF WOOD SAWING PLANNING SOFTWARE SYSTEM

The paper describes research of task of wood sawing planning and development of algorithm for its solving. The aim of the sawing process consists in processing round wood into sawn lumber, as well as technological wood chips. The logs are cut into sawn lumber according to a plan, developed in advance. The sawing pattern is a scheme of sawing of a separate log (or sorting group of logs with approximately same diameters) into sawn lumber of demanded sizes. After the calculation of sawing patterns for each sorting groups of logs, a monthly plan of cutting of all raw material is made. Preparation of such plan is a highly responsible task, because one of the main targets is to produce required lumber from available raw materials with minimal waste. The problem of sawing patterns calculation consists in specification of sizes and number of lumber to be cut from each log of given quality, length and diameter. The solution to this problem must also take into account all features, limitations and parameters of process equipment, as well as of raw material and production orders .The problem is linear programming problem with additional constraint, the columns generation method is used. Special attention is paid to criteria of mass production, which excludes this task from linear programming class. Algorithm for solving this problem was tested on several different real production plans, and its efficiency estimate is given. The software system was tested on real operating data of several sawmills. Saving of raw materials, improving of monthly profit and reduction of idle times were confirmed by the mill staff.