Chapter 6 Facilities Layout

Layout - the arrangement or configuration of departments, work centers, and equipment within the confines of a building or area Focuses on the movement of work (customers or material) through the system May involve designing a completely new layout or redesigning an exiting layout MTSU Management 362

The Need for Layout Decisions (1 of 2) Inefficient operations Changes in the design of products or services For Example: High Cost Bottlenecks Accidents The introduction of new products or services Safety hazards MTSU Management 362

The Need for Layout Designs (2 of 2) Changes in environmental or other legal requirements Changes in volume of output or mix of products Morale problems Changes in methods and equipment MTSU Management 362

Basic Layout Types Product Process Fixed Position Combination Cellular Other service layouts warehouse and storage retail office MTSU Management 362

Examples include production lines and assembly lines Product Layout (1 of 3) Uses standardized processing operations to achieve smooth, rapid, high-volume flow Work stations or areas are arranged according to a fixed sequence of tasks required to produce a product Examples include production lines and assembly lines MTSU Management 362

Product Layout (2 of 3) Work stations are arranged so that the output of one is an input to the next, i.e., a series connection Layout design involves assigning one or more of the tasks (time) required to make a product to work stations Raw materials or customer Finished item Station 2 3 4 Material and/or labor 1 MTSU Management 362

Product Layout (3 of 3) Advantages Disadvantages High rate of output Low unit cost Labor specialization Specialized equipment Low material-handling cost High utilization of labor and equipment Routing and scheduling designed initially Accounting, purchasing, and inventory control fairly routine Disadvantages Dull, repetitive jobs Unskilled workers Fairly inflexible Susceptible to shutdowns PM, quick repairs, and spare equipment parts Incentive plan impractical MTSU Management 362

A U-Shaped Production Line Figure 6-3 A U-Shaped Production Line Out In More compact than the straight production line Permits increased communication among workers Increased flexibility in work assignments Materials enter at about the same place that finished products exit 10 1 9 2 Workers 8 3 7 4 6 5 MTSU Management 362

Layout that can handle varied processing requirements Process Layout (1 of 3) Layout that can handle varied processing requirements each product/service may require a different sequence of operations (routing) wide variety of products/services in small volumes Work areas are arranged according to the processes being performed, i.e., like processes are located together MTSU Management 362 10 10 9 9 9

Process Layout - work travels to dedicated process centers Process Layout (2 of 3) Milling Assembly & Test Grinding Drilling Plating Process Layout - work travels to dedicated process centers MTSU Management 362

Process Layouts (3 of 3) Advantages Disadvantages Handles a variety of processing requirements Not vulnerable to equipment failure General-purpose equipment Individual incentive systems possible Disadvantages In-process inventory can be high routing and scheduling challenging Equipment utilization low Material-handling cost high High supervision costs High unit cost Accounting, purchasing, and inventory control challenging MTSU Management 362

Fixed-Position Layout Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed Used in large construction projects Scheduling of resources is an issue in this type of layout MTSU Management 362

Combination Layout Most real-world layouts are some combination or variation of product and process layouts The mix that makes up the combination is determined by the needs of the customer MTSU Management 362

Cellular Manufacturing Cellular Layouts Cellular Manufacturing Layout in which machines are grouped into a cell that can process items that have similar processing requirements Group Technology The grouping into families of items(parts) with similar design or manufacturing characteristics MTSU Management 362

Cellular Manufacturing Layout Figure 6-5 Cellular Manufacturing Layout Heat treat Gear cut -1111 Lathe Mill Drill -1111 Heat treat 222222222 Mill Drill Grind - 2222 Assembly Heat treat 3333333333 Lathe Mill Grind - 3333 Gear cut - 4444 44444444444444 Mill Drill MTSU Management 362

Work Cells A hybrid between a process-oriented and product-oriented layouts Group technology identifies a family of items that require similar processing The processes shared by the members of a family form a small product layout Volume of the entire family justifies the dedication of resources Requires a high level of training and flexibility on the part of the employees MTSU Management 362

Cellular Layouts — Some Advantages Reduced work-in-process inventory Less floor space required Reduced raw material and finished goods inventories required Reduced direct labor costs Heightened sense of employee participation Increased utilization of equipment machinery Reduced investment in machinery and equipment MTSU Management 362

Warehouse and storage layouts Other Service Layouts Warehouse and storage layouts frequency of order an important factor number and width of aisles height of storage racks material-handling methods Retail layouts an objective is to maximize profitability per square foot of shelf space traffic patterns, traffic flow and product placement are important factors Office layouts MTSU Management 362

Information Needed to Design a Good Layout an understanding of capacity of the area and the space and other requirements for processes identification of the cost of moving materials between the various work areas selection of appropriate material handling equipment identification and understanding of the requirements for information flow to support the flow of work decisions regarding environment and aesthetics MTSU Management 362

Designing Product Layouts (1 of 3) Required tasks are assigned to work stations The objective is to minimize the workers’ idle time therefore idle time costs, and meet the required production rate for the line Raw materials or customer Finished item Station 2 3 4 Material and/or labor 1 MTSU Management 362

Designing Product Layouts (2 of 3) Ideally, each workers would be assigned the same amount of work (time), i.e., the required work would be balanced among the work stations all workers would complete their assigned tasks at the same time (assuming they start their work simultaneously) this would result in no idle time MTSU Management 362

Designing Product Layouts (3 of 3) Unfortunately there are conditions that can prevent the achievement of a perfectly balanced line The estimated times for tasks The precedence relationships for the tasks The combinatoric nature of the problem MTSU Management 362

Inputs Needed To Design a Product Layout (1 of 2) The production rate required from the product layout or the cycle time. The cycle time is the reciprocal of the production rate and visa versa All of the tasks required to make the product It is assumed that these tasks can not be divided further MTSU Management 362

Inputs Needed To Design a Product Layout (2 of 2) The estimated time to do each task The precedence relationships between the tasks determined by the technical constraints imposed by the product design displayed as a network known as a precedence diagram MTSU Management 362

Line Balancing Procedure (1 of 6) If not provided, find the cycle time. Remember the cycle time is the reciprocal of the production rate. The cycle time is expressed in the same time units as the estimated task times Determine the selection heuristic (rule of thumb) that may be used to help with the assignments MTSU Management 362

Line Balancing Procedure (2 of 6) Some Heuristic (Intuitive) Rules Assign tasks in order of longest task time Assign tasks in order of most following tasks Assign tasks in order of greatest positional weight Positional weight is the sum of each task’s time and the times of all following tasks MTSU Management 362

Line Balancing Procedure (3 of 6) Open a new station with the full cycle time remaining Determine which unassigned tasks are feasible, i.e., can be assigned to this station at this time MTSU Management 362

Line Balancing Procedure (4 of 6) For a task to be feasible, two conditions must be met All tasks that precede that task must have already been assigned The estimated task time must be equal to or less than the remaining cycle time for that work station MTSU Management 362

Line Balancing Procedure (5 of 6) If there is only one feasible task, assign it to the station. If there is more than one feasible task, use the heuristic (step 2) to determine which task to assign. Reduce the station’s remaining cycle time by the estimated time for the assigned task. Return to step 4. MTSU Management 362

Line Balancing Procedure (6 of 6) If there are no feasible tasks, assignments to that station are complete. Go back to step 3. Stop when all tasks have been assigned to stations MTSU Management 362

Line Balancing Relationships MTSU Management 362

The Precedence Diagram Problem 2, page 299 0.5 1.4 0.5 0.6 c f a b 0.5 0.7 h d 1.0 g 0.8 e Return MTSU Management 362

Parallel Workstations 1 min. 2 min. 30/hr. Bottleneck 1 min. 2 min. 60/hr. 30/hr. Parallel Workstations 1 min. MTSU Management 362

Designing Process Layouts Determine the relative positioning of the departments Arrangement can be influenced by external factors Typically when one department is moved at least one other department will have to move This results in a combinatoric problem, i.e., a large number of possible arrangements MTSU Management 362

Measures of Effectiveness A major objective is to find an arrangement which minimizes material-handle cost, distance, or time Other concerns include cost of changing an existing layout expected operating costs amount of effective capacity created ease of modifying the system MTSU Management 362

Information Requirements Dimensions of departments; dimension of building Forecast of flows between each pair of work centers Distance between locations and material-handling cost/unit of distance Financial resources Special considerations MTSU Management 362

Interdepartmental Work Flows for Assigned Departments Figure 6-10 Interdepartmental Work Flows for Assigned Departments 30 170 100 1 3 2 A B C MTSU Management 362

Alternative Approaches Closeness ratings ranks the importance that each pair of departments be close together rating can incorporate qualitative and quantitative information allows the consideration of areas not in the flow of “material” Computer analysis MTSU Management 362

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