1 Facility Layout: Manufacturing and Services Manufacturing and Services Chapter 5, Part B

2 Facility Layout Facility layout means planning: l for the location of all machines, utilities, employee workstations, customer service areas, material storage areas, aisles, restrooms, lunchrooms, internal walls, offices, and computer rooms l for the flow patterns of materials and people around, into, and within buildings

3 Locate All Areas In and Around Buildings l Equipment l Work stations l Material storage l Rest/break areas l Utilities l Eating areas l Aisles l Offices

4 Characteristics of the Facility Layout Decision l Location of these various areas impacts the flow through the system. l The layout can affect productivity and costs generated by the system. l Layout alternatives are limited by l the amount and type of space required for the various areas l the amount and type of space available l the operations strategy l... more

5 Characteristics of the Facility Layout Decision Layout decisions tend to be: l Infrequent l Expensive to implement l Studied and evaluated extensively l Long-term commitments

6 Manufacturing Facility Layouts

7 Materials Handling l The central focus of most manufacturing layouts is to minimize the cost of processing, transporting, and storing materials throughout the production system. l Materials used in manufacturing include: l Raw material l Purchased components l Work-in-progress l Finished goods l Packaging material l Maintenance, repair, and operating supplies

8 Materials Handling A materials-handling system is the entire network of transportation that: l Receives material l Stores material in inventories l Moves material between processing points l Deposits the finished products into vehicles for delivery to customers

9 Materials Handling Material-Handling Principles l Move directly (no zigzagging/backtracking) l Minimize human effort required l Move heavy/bulky items the shortest distances l Minimize number of times same item is moved l MH systems should be flexible l Mobile equipment should carry full loads

10 Materials Handling Material-Handling Equipment l Automatic transfer devices l Containers/pallets/hand carts l Conveyors l Cranes l Elevators l Pipelines l Turntables l AGVS

11 Basic Layout Forms l Process l Product l Cellular l Fixed-Position l Hybrid

12 Process (Job Shop) Layouts l Equipment that perform similar processes are grouped together l Used when the operations system must handle a wide variety of products in relatively small volumes (i.e., flexibility is necessary)

13 Characteristics of Process Layouts l General-purpose equipment is used l Changeover is rapid l Material flow is intermittent l Material handling equipment is flexible l Operators are highly skilled l... more

14 Characteristics of Process Layouts l Technical supervision is required l Planning, scheduling and controlling functions are challenging l Production time is relatively long l In-process inventory is relatively high

15 Product (Assembly Line) Layouts l Operations are arranged in the sequence required to make the product l Used when the operations system must handle a narrow variety of products in relatively high volumes l Operations and personnel are dedicated to producing one or a small number of products

16 Characteristics of Product Layouts l Special-purpose equipment are used l Changeover is expensive and lengthy l Material flow approaches continuous l Material handling equipment is fixed l Operators need not be as skilled l... more

17 Characteristics of Product Layouts l Little direct supervision is required l Planning, scheduling and controlling functions are relatively straight-forward l Production time for a unit is relatively short l In-process inventory is relatively low

18 Cellular Manufacturing Layouts l Operations required to produce a particular family (group) of parts are arranged in the sequence required to make that family l Used when the operations system must handle a moderate variety of products in moderate volumes

19 Characteristics of Cellular Manufacturing Relative to Process Layouts l Equipment can be less general-purpose l Material handling costs are reduced l Training periods for operators are shortened l In-process inventory is lower l Parts can be made faster and shipped more quickly

20 Characteristics of Cellular Manufacturing Relative to Product Layouts l Equipment can be less special-purpose l Changeovers are simplified l Production is easier to automate

21 Fixed-Position Layouts l Product remains in a fixed position, and the personnel, material and equipment come to it l Used when the product is very bulky, large, heavy or fragile

22 Hybrid Layouts l Actually, most manufacturing facilities use a combination of layout types. l An example of a hybrid layout is where departments are arranged according to the types of processes but the products flow through on a product layout.

23 New Trends in Manufacturing Layouts l Designed for quality l Designed for flexibility - to quickly shift to different product models or to different production rates l Cellular layout within larger process layouts l Automated material handling l U-shaped production lines l... more

24 New Trends in Manufacturing Layouts l More open work areas with fewer walls, partitions, or other obstacles l Smaller and more compact factory layouts l Less space provided for storage of inventories throughout the layout

25 Planning Manufacturing Facility Layouts Two Categories of Software Tools l Computer aided design (CAD) l Allows 3-D, full-color views of facility design l Allows virtual walk-throughs l Ex. – ArchiCAD, AutoSketch, AutoCAD l Computer simulation l Can simulate proposed system layout in operation and measure its performance l Ex. – ProModel, VisFactory, SIMPROCESS

26 l Process and Warehouse Layouts l Product Layouts l Cellular Manufacturing Layouts Planning Manufacturing Facility Layouts

27 Planning Manufacturing Facility Layouts Process Layouts l Primary focus is on the efficient flow of materials l The wide variety of potential product routings through the facility can be evaluated using computer simulation l Warehouse Layouts l Primary focus is the fast storage and retrieval of inventory items l Decisions about aisle size/placement and location of each inventory item can be evaluated using computer simulation

28 Planning Manufacturing Facility Layouts Product Layouts l Primary focus is on the analysis of production lines l The goal of the production line analysis is to: l Determine how many workstations to have l Determine which tasks to assign to which workstation l Minimize the number of workers & machines used l Provide the required amount of capacity l Line balancing is a key part of the analysis

29 Planning Product Layouts Line Balancing Procedure 1. Determine the tasks involved in completing 1 unit 2. Determine the order in which tasks must be done 3. Draw a precedence diagram 4. Estimate task times 5. Calculate the cycle time 6. Calculate the minimum number of workstations 7. Use a heuristic to assign tasks to workstations

30 Planning Product Layouts Line Balancing Heuristics l Heuristic methods, based on simple rules, have been developed to provide good (not optimal) solutions to line balancing problems l Heuristic methods include: l Incremental utilization (IU) method l Longest-task-time (LTT) method l … and many others

31 Planning Product Layouts Incremental Utilization Method l Add tasks to a workstation in order of task precedence one at a time until utilization is 100% or is observed to fall l Then the above procedure is repeated at the next workstation for the remaining tasks l Pro – Appropriate when one or more task times is equal to or greater than the cycle time l Con – Might create the need for extra equipment

32 Planning Product Layouts Longest-Task-Time Method l Adds tasks to a workstation one at a time in the order of task precedence. l If two or more tasks tie for order of precedence, the one with the longest task time is added l Conditions for its use: l No task time can be greater than the cycle time l There can be no duplicate workstations

33 Example: Armstrong Pumps l Line Balancing Armstrong produces bicycle tire pumps on a production line. The time to perform the 6 tasks in producing a pump and their immediate predecessor tasks are shown on the next slide. Ten pumps per hour must be produced and 45 minutes per hour are productive. Use the incremental utilization heuristic to combine the tasks into workstations in order to minimize idle time.

34 Example: Armstrong Pumps l Line Balancing Tasks that Time to Tasks that Time to Immediately Perform Task Precede Task (min.) Task Precede Task (min.) A A BA 3.2 BA 3.2 C C D B,C 2.8 D B,C 2.8 ED 17.1 ED 17.1 FE 12.8 FE 12.8 Total = 42.8

35 Example: Armstrong Pumps l Line Balancing – Network (Precedence) Diagram AA CC BBEEDDFF

36 Example: Armstrong Pumps l Line Balancing – Cycle Time = 45/10 = 4.5 minutes per pump

37 Example: Armstrong Pumps l Line Balancing – Minimum Number of Workstations Minimum Minimum Number of Number ofWorkstations = [(42.8)(10)]/45 = 9.51 workstations = [(42.8)(10)]/45 = 9.51 workstations

38 Example: Armstrong Pumps l Line Balancing – Incremental Utilization Heuristic WS Tasks Mins./pump #WS’s Incr.Util. 1A /4.5=1.2= % 1A /4.5=1.2= % 1A,B /4.5=1.9= % 1A,B /4.5=1.9= % 1A,B,C /4.5=2.2= % 1A,B,C /4.5=2.2= % 2C /4.5=.33= % 2C /4.5=.33= % 2C,D /4.5=.96= % 2C,D /4.5=.96= % 2C,D,E /4.5=4.8= % 2C,D,E /4.5=4.8= % 3E /4.5=3.8= % 3E /4.5=3.8= % 3E,F /4.5=6.6= % 3E,F /4.5=6.6= % 4F /4.5=2.8= % 4F /4.5=2.8= %

39 Example: Armstrong Pumps l Line Balancing – Utilization of Production Line = 9.51/10 =.951 = 95.1% = 9.51/10 =.951 = 95.1%

40 Planning Product Layouts Rebalancing a Production Line l Changes that can lead to production lines being out of balance or having insufficient/excess capacity are: l Changes in demand l Machine modifications l Variations in employee learning and training

41 Planning Cellular Manufacturing Layouts l Cell Formation Decision l Which machines are assigned to manufacturing cells l Which parts will be produced in each cell

42 Planning Cellular Manufacturing Layouts l Fundamental Requirements for Parts to be Made in Cells l Demand for the parts must be high enough and stable enough that moderate batch sizes of the parts can be produced periodically. l Parts must be capable of being grouped into parts families.

43 Planning Cellular Manufacturing Layouts More-Complex Issues to be Resolved l If all the parts cannot be cleanly divided between cells, how will we decide which are to be the exceptional parts? l If inadequate capacity is available to produce all the parts in cells, which parts should be made outside the cells?

44 Planning Cellular Manufacturing Layouts Cell Formation Procedure 1. Form the Parts-Machines Matrix. 2. Rearrange the Rows. l Place the machines that produce the same parts in adjacent rows. 3. Rearrange the Columns. l Place the parts requiring the same machines in adjacent columns. 4. Use the rearranged parts-machines matrix to identify cells, the machines for that cell and the parts that will be produced in that cell.