Reducing waste with an optimized trimming model in production planning

• Main Authors: Hallbäck, Sofia, Paulsson, Ellen
• Format: Others
• Language: English
• Published: Umeå universitet, Institutionen för matematik och matematisk statistik 2020
• Subjects: Cutting stock problem; knapsack problem; trimming; optimization; carton board; forest industry; mathematical modeling; Mathematics; Matematik
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-173253

In which ways can the process of trimming dispersion coated board products be optimized so as to reduce material waste and increase production efficiency? This is the question that this master thesis report seeks to answer. In paper production, alot of waste is generated when cutting production reels into customer reels. Some material waste are necessary in order to ensure good quality, however a large amount of the wastecould be reduced if the cutting process was to be optimized. During this project, carried out at a forest company, a mathematical optimization model was developed in order to reduce waste and save costs. This model is based on a cutting stock problem using column generation approach. It provides as its output cutting patterns and an optimal allocation of rolls for production purposes, which implies minimizing the number production rolls needed.The visualization of the results could also be used to achieve optimal stock levels, and easier keep track on how to use the material available in stock. Findings show that there are potential savings to be done. Simulations suggest an implementation of this model could result in material savings of around 7 %. This could also translateto environmental savings in CO2, where every decrease of one tonne material equals to adecrease in CO2emissions of 500 kg