Optimization of the cutting planning process in cardboard and paper production
Authors: Sanginova Olga , Kozlov Pavlo 
Published: July 2021

Improving the production efficiency is one of the main management tasks for the pulp and paper industry.

This can be achieved through the use of automated planning systems, designed to take into account the features and limitations of particular production. Such systems allow, on the basis of orders received from consumers, a voluminous production schedule to be made to take into account the needs for raw materials, the productivity of paper or cardboard machines, and the optimal cutting of the canvas on longitudinal cutting machines.

Linear programming method for solving optimization problems. Computer simulation using optimized packages to compare the results with the options used in production.

Cutting planning processes were optimized on the basis of standard orders for rolled products of an enterprise in the Kyiv region. The problem of optimizing the cutting planning process and criteria for increasing the production efficiency is formalized. The target function is to increase the profit of production by minimizing material losses in planning the cutting of the master rill and minimizing the storage of related products in production warehouses. To solve the optimization problem, it is proposed to use our own method of calculating the optimal cutting patterns for the manufacture of finished products on a longitudinal cutting machine.

The MS Office SOLVER package was used for the calculations.

Different cutting options were compared via the target function. Important criteria for this inspection are the fulfillment of the entire order, the availability and storage of related products outside the order, and the minimization of time for the reconfiguration of machines. Longitudinal cutting machines of this production can be adjusted only manually, and it takes a long time. Also, technological restrictions on the allowable width of the edge are an important requirement for cutting patterns. All patterns that do not meet these restrictions cannot be compared.

There are three options for comparison. An option is made according to the proposed method and with an optimization package using the Simplex method and a number of technological limitations inherent in this production. An option is selected by the production planner manually taking into account previous experience. And the variant of cutting orders is made by the production management system, which accompanies the process of planning and transfer of tasks for longitudinal cutting machines. The function takes the maximum value in the option offered by the production scheduler. But this option is not optimal, because a person adds rolls to the satellite to improve the cutting map to fulfill all orders. This in turn leads to overfulfillment of orders and production of additional products in a warehouse where they can be stored for years until the expiration date. The option offered by the automotive system does not require the use of accompanying rolls but unfortunately does not meet the requirements for optimal cutting of the material. Automatic cutting leaves a large edge that is already within the maximum allowable limitations of the machines and, moreover, does not lead to the execution of the entire order. This violates the basic requirement for production such as full execution of the order. Therefore, this option cannot be used either. The optimal cut for profit maximization is the option obtained using the roll planning technique. This technique allows the average weight of the roll to be obtained through the use of production history. The estimated weight is used to convert the order from tons to the number of pieces. Cutting patterns for the production of the order in this way are presented and, taking into account the technological limitations of production, can be calculated on the basis of the Simplex method in optimization packages. Such cutting patterns have no satellites and allow the fulfilment of all orders.

The roll planning technique reduces the number of clippings and avoids overproduction. The analysed cutting plans show that the use of satellites reduces the profitability of the enterprise and does not always minimize material costs.