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1、Facility Layout,Chapter Eight,Copyright 2014 by The McGraw-Hill Companies, Inc. All rights reserved.,McGraw-Hill/Irwin,Learning Objectives,LO81: Analyze the common types of manufacturing layouts. LO82: Illustrate layouts used in nonmanufacturing settings.,8-2,Layout Decisions,Facility layout: the pr
2、ocess of determining placement of departments, workgroups within departments, workstations, machines, and stock-holding points within a facility This process requires the following inputs: Specification of the objectives used to evaluate the design Estimates of product or service demand Processing r
3、equirements Space requirements for the elements Space availability within the facility,8-3,Basic Production Layout Formats,Workcenter (job-shop or functional layout) Similar equipment are grouped together. Assembly line (flow-shop layout) Work processes are arranged according to the steps by which t
4、he product is made. Manufacturing cell Dissimilar machines are grouped to work on similar products. Project layout Product remains at one location.,8-4,Workcenters,Given The flow (number of moves) to and from all departments The cost of moving from one department to another The existing or planned p
5、hysical layout of the plant Determine The “best” locations for each department, where best means maximizing flow, which minimizes costs,8-5,Example 8.1: Toy Factory,Goal is to arrange eight workcenters to minimize interdepartmental handling cost. Assume all workcenters have same space and fit in bui
6、lding. All material is transported in standard crates by forklift. Transportation costs are $1 to move between adjacent workcenters. Extra $1 for each workcenter in between,8-6,Steps,Illustrate the interworkcenter flow by a model. Determine the cost of this layout. Search for workcenter location cha
7、nges that will reduce costs.,8-7,Example 8.1: Interworkcenter Flow, and Building Dimensions and Workcenters,8-8,Example 8.1: Interworkcenter Flow Graph with Number of Annual Movements,8-9,Example 8.1: Cost MatrixFirst Solution,8-10,Example 8.1: Revised Interworkcenter Flowchart and Cost MatrixSecond
8、 Solution,8-11,Systematic Layout Planning,Numerical flow of items between workcenters Can be impractical to obtain Does not account for the qualitative factors that may be crucial to the placement decision Systematic layout planning Accounts for the importance of having each department located next
9、to every other department Is also guided by trial and error Switching workcenters then checking the results of the “closeness” score,8-12,Systematic Layout Planning for a Floor of a Department Store,8-13,Assembly Line,Assembly line: progressive assembly linked by some material handling device Some f
10、orm of pacing is present and the allowable processing time is equivalent for all workstations Important differences: Material handling devices Line configuration Pacing Product mix Workstation characteristics Length,8-14,Assembly-Line Design,Workstation cycle time: a uniform time interval in which a
11、 moving conveyor passes a series of workstations Also the time between successive units coming off the line Assembly-line balancing: assigning all tasks to a series of workstations so that each workstation has no more than can be done in the workstation cycle time Precedence relationship: the order
12、in which tasks must be performed in the assembly process,8-15,Assembly-Line Balancing,Specify the sequential relationships among tasks. Determine the required workstation cycle time. Determine the theoretical minimum number of workstations. Select a primary and secondary assignment rule. Assign task
13、s. Evaluate the efficiency of the balance. Rebalance if needed.,8-16,Assembly-Line Balancing Formula,8-17,Example 8.2: Assembly Steps and Times,8-18,Example: Precedence Graph,8-19,Example: C and Nt,8-20,Example: Assignment,8-21,Example: Efficiency,8-22,Task Splitting,Split the task Share the task Us
14、e parallel workstations Use a more skilled worker Work overtime Redesign,8-23,Flexible Line Layouts,Problem operators trapped in “cages” prevents sharing work among them,Solution remove barriers so operators can trade work and operators can be added or removed as needed,8-24,Flexible Line Layouts,Pr
15、oblem operators “birdcaged” with no opportunity to share work or add third operator,Solution operators can help each other and third operator can be added if needed,8-25,Flexible Line Layouts,Problem straight line is difficult to balance,Solution U-shaped line gives better operator access and may re
16、duce need for operators,8-26,Mixed-Model Line Balancing,Most factories produce a number of different products. Inventory can be reduced by building some of each product during every period (e.g., day, week, etc.). Mixed-model line balancing is one means of scheduling this varied production.,8-27,Example 8.3: Mixed-Model Line Balancing,Processing must be completed for both Model J and Model K wagons. Equal number of each model are required. Cycle time 6 minutes for Model J and 4 minutes for Model K. In an 8-hour day, how should the models be processed?,
