Cutting optimisation with variable-sized stock and inventory status data

Many production environments require economical cutting of onedimensional items according to bills of materials from objects of several standard lengths. However, even with optimised cutting substantial trim loss may occur. This trim loss should not be regarded as waste. It is returned to store and can be reused in future optimisations. Optimisation of packing linear items into standard lengths is presented for items which cannot be packed into available lengths from inventory status data. The core of the proposed optimisation tackles the variable-sized bin packing problem (VBPP). The article presents a hybrid genetic algorithm which packs items into both available objects from the inventory and variable-sized objects from the stock. The algorithm tries to minimise waste. Large trim-loss items are returned as remnants to the inventory for subsequent optimisations. ∗To whom correspondence should be addressed. e-mail: [email protected] †University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, SI-1000 Ljubljana, Slovenia