介绍 operation management 项目管理8.ppt

Product and Service Processes * * * * * * * * * * * 6-* In-process inventory costs can be high Challenging routing and scheduling Equipment utilization rates are low Material handling slow and inefficient Complexities often reduce span of supervision Special attention for each product or customer Accounting and purchasing are more involved Disadvantages of Process Layouts 6-* Fixed-Position Layouts Fixed-position Layout: Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed Nature of the product dictates this type of layout Weight Size Bulk Large construction projects 6-* Cellular Production Layout in which machines are grouped into a cell that can process items that have similar processing requirements Group Technology The grouping into part families of items with similar design or manufacturing characteristics Cellular Layouts 6-* Dimension Functional Cellular Number of moves between departments many few Travel distances longer shorter Travel paths variable fixed Job waiting times greater shorter Throughput time higher lower Amount of work in process higher lower Supervision difficulty higher lower Scheduling complexity higher lower Equipment utilization lower higher Table 6.3 Functional vs. Cellular Layouts 6-* Warehouse and storage layouts Retail layouts Office layouts Service layouts must be aesthetically pleasing as well as functional Service Layouts 6-* Line balancing is the process of assigning tasks to workstations in such a way that the workstations have approximately equal time requirements. Design Product Layouts: Line Balancing 6-* Cycle time is the maximum time allowed at each workstation to complete its set of tasks on a unit. Cycle Time 6-* Determine Maximum Output 6-* Determine the Minimum Number of Workstations Required 6-* Precedence diagram: Tool used in line balancing to display elemental tasks and sequence requirements A Simple Precedence Diagram a b c d e 0.1 min. 0.7 min.