Abstract: A production scheduling method was proposed for injection molding(IM) process with multiple products produced by a single machine,in order to achieve global minimum energy consumption.The total energy consumption was split into three parts.The first part was defined as switchover energy consumption,i.e.,the energy used for replacing the die and mold,changing the color or material,etc.The second part was defined as transitional energy consumption,which was determined by the regulation time for controlling the end-product with desired quality.The third part was the energy consumed during the stable production periods,which was defined as stable energy consumption.The total energy consumption model was described by a directed graph,where the nodes represented the stable production of different products and the arcs represented product switchovers.The single-machine-multi-product scheduling problem was formulated as a typical traveling salesman problem(TSP).A genetic algorithm(GA) based lexicographic optimization framework was proposed to solve such a scheduling problem.The first-layer optimization was to search the feasible process parameters that contributed to reliable production of each product.The second-layer optimization was to solve a TSP problem by finding the optimal switching path among the multiple products in order to minimize the global energy consumption. The proposed scheduling method could improve production efficiency and reduce energy consumption. Experimental results in laboratory scale tests demonstrated its feasibility and effectiveness.

Key words: injection molding process, multiple products, energy saving, parameter optimization, production scheduling

摘要： 为减小单机多产品注塑过程的生产总能耗,提出一种基于旅行商算法(TSP)和遗传算法(GA)的节能调度方法。研究了注塑生产总能耗的3个重要组成:产品切换能耗、过渡调整能耗和稳定生产能耗,建立了产品切换过渡的能耗模型。以单产平稳模态为节点、过渡模态为支路,建立了单机多产品过程生产总能耗的有向图模型,将单机多产品能耗优化问题转化为经典的TSP问题。采用基于遗传算法的多目标逐层优化与TSP路径寻优思想,搜索各个单产平稳生产下的最优操作参数以及多产品的最优生产顺序,以期降低生产总能耗。该方法可提高生产效率,降低生产能耗。应用研究结果验证了方法的可行性和有效性。

关键词: 注塑过程, 多产品, 节能, 参数优化, 生产调度