考虑机器间替代性的制造单元柔性度量

Flexibility Measurement of Manufacturing Cell Considering Machine Substitution

本文在假定柔性制造单元中的各台机器能够以不同效率实现任务的替代加工的基础上,建立了包含时间和成本的效率矩阵,综合考虑任务出现的概率、每台机器可加工的任务数量、任务在机器间一次指派和二次指派的概率以及任务在机器间的替代比例和替代概率等困扰实际生产因素的制造单元的柔性度量方法。最后,结合算例对该方法的应用过程进行了分析。

Manufacturing flexibility has become an important capability of many production systems, and it has been seen as important as cost, quality and delivery. The current literature, however, only includes a few technological attributes that can be found in manufacturing systems, such as time dimension, cost dimension and range dimension. Manufacturing cell is the most basic element of manufacturing system, and manufacturing cell flexibility measurement has the following three main effects. First, in the design and establishment of a new flexible manufacturing system, flexibility design can help new systems reduce their investment risk. Second, evaluation of the existing flexibility of one flexible manufacturing system can effectively improve the flexibility. Third, it is important to deal with accidental damage and balance the cost of losses and flexibility. In this paper, the ability for a manufacturing cell to easily adapt to various uncertainties in its production system is described as flexibility, and one of its main characters is machine substitution among all the machines in this cell. We suppose that machine substitution is considered in case any disruption occurs in the manufacturing cell. Each machine in one manufacturing cell can substitute others in processing tasks with different efficiency. In case that disturbance occurs, a manufacturing cell flexibility measurement method, including efficiency matrix, is offered, and a number of different tasks are performed. Finally, this manufacturing cell flexibility measurement method is verified with an example to show its application process. It is noteworthy that manufacturing cell flexibility is connected tightly with operational cost. When manufacturing cell has several machines that can be substituted between each other, this condition will give the system greater flexibility, but inevitably lead to an increase in investment cost. Companies need to design which machines should have the ability of substitution and find a balance between flexibility and cost.