Facility Layout: Manufacturing and Services

Transcription

1 Facility Layout: Manufacturing and Services 1

2 Facility Layout: Manufacturing and Services The aim of layout design is to organize the physical arrangement of economic activity centers within a facility so that a process can be as efficient as possible. An economic activity center can be anything that consumes space: a person, or group of people, a teller window, a m achine, a workbench or work station, a departm ent, a stairway or an aisle, a tim ecard-rack, a cafeteria, or storage room, and so on. 2

3 Facility layout means: Planning for the location of all machines, utilities, employee-workstations, customer-service-areas, material-storage-areas, aisles, restrooms, lunchrooms, internal walls, offices, and computer rooms Planning for the flow patterns of materials and people around, into, and within buildings Location or arrangement of everything within & around buildings

4 The Need for Layout Decisions Inefficient operations For Example: High Cost Bottlenecks The introduction of new products or services Changes in the design of products or services Accidents Safety hazards

5 The Need for Layout Designs (Cont d) Changes in environmental or other legal requirements Changes in volume of output or mix of products Changes in methods and equipment Morale problems Example: Fact-to-face contact

6 Objectives of Facility Layout 9 Minimize material handling costs 9 Utilize space efficiently 9 Utilize labor efficiently 9 Eliminate bottlenecks 9 Facilitate communication and interaction between workers, between workers and their supervisors, or between workers and customers 9 Reduce manufacturing cycle time or customer service time

7 Objectives of Facility Layout (Contd.) 9 Eliminate waste or redundant movement 9 Facilitate the entry, exit, and placement of material, products, or people 9 Incorporate safety and security measures 9 Promote product and service quality 9 Encourage proper maintenance activities 9 Provide a visual control of operations or activities 9 Provide flexibility to adapt to changing conditions 9 Increase capacity

8 The overall Objectives of Layout Design To arrange the facilities needed by a process so that desired output is achieved with minimum resources. OR To lay out available facilities so that the maximum output is achieved. These objectives must be met without breaking a number constraints which result from Product Design Planned capacity Process Used Space available Constraints of the building Other site constraints Appropriate material handling Capital investment available Service areas needed Communications and information flows Requirements of employees Safety Quality of environment and so on 8

9 Strategic Importance of Layout Proper layout enables: Higher utilization of space, equipment, and people Improved flow of information, materials, or people Improved employee morale and safer working conditions Improved customer/client interaction Flexibility

10 Requirements of a Good Layout an understanding of capacity and space requirements selection of appropriate material handling equipment decisions regarding environment and aesthetics identification and understanding of the requirements for information flow identification of the cost of moving between the various work areas

11 Characteristics of the Facility Layout Decision Location of various economic activities center areas and its impacts of the flow through the system. The layout can affect productivity and costs generated by the system. Layout alternatives are limited by the amount and type of space required for the various areas the amount and type of space available the operations strategy Layout decisions tend to be Infrequent Expensive to implement Studied and evaluated extensively Long-term commitments

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

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

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

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

16 A Classification of Layouts Process Layout Machines grouped by process they perform [ deals with low-volume, high-variety production ( job shop, interm ittent production)] Example: Job shops, hospitals, kitchen. Product Layout Linear arrangem ent of w orkstations to produce a specific product [ seeks the best personnel and m achine use in repetitive or continuous production] Exam ple: electronic assemble, milk bottling. Hybrid ( including group) Layout Example: fast-food restaurants, airport passenger terminals Fixed Position Layout Layout in w hich the product or project rem ains stationary, and w orkers, m aterials, and equipm ent are m oved as needed [ large bulky projects such as ships and buildings] Exam ple: Shipbuilding, road laying Specialized Layout Example: offices, warehouses, retails

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

18 Manufacturing Process Layout Lathe Department L L Milling Department M M Drilling Department D D D D L L M M D D D D L L G G G P L L L L G G Grinding Department Receiving and Shipping G P Painting Department A A A Assembly 18

19 Manufacturing Process Layout Lathe Department L L Milling Department M M Drilling Department D D D D L L M M D D D D L L G G G P L L L L G G Grinding Department Receiving and Shipping G P Painting Department A A A Assembly 19

20 Manufacturing Process Layout Lathe Department L L Milling Department M M Drilling Department D D D D L L M M D D D D L L G G G P L L L L G G Grinding Department Receiving and Shipping G P Painting Department A A A Assembly 20

21 Characteristics of Process Layouts General-purpose equipment is used Changeover is rapid Material handling equipment is flexible Operators are highly skilled Technical supervision is required Production time is relatively long In-process inventory is relatively high Planning, scheduling and controlling functions are challenging

22 Designing Process Layouts An Important Objective: Minimize the costs associated with movement of materials, people, etc. 9 Block Diagramming Minimize nonadjacent loads Use when quantitative data is available Addresses a single criteria/objective [generally minimizing transportation costs or distance traveled] 9 Relationship Diagramming - Systematic Layout Planning Based on location preference between areas Use when quantitative data is not available Can be used for multi criteria/objective situation

23 Designing Process Layouts [Contd.] There are three steps in the overall design: (1) Collect relevant information concerning: (a) space required for each area (b) quantities moved between area (c) number of trips between areas (d) and so on. (2) Build a general Block Plan [Block Diagram] and try to minimize the total movement (3) Add details to the Block Plan to give a final layout (using architects, engineers, consultants and other expertise). Note: The key step of this process is the second, where a general block plan is produced. Further, this block plan has to be evaluated to finalize.

24 Designing Process Layouts [Contd.] A Procedure to evaluate the Block Plan 1) List the separate areas or departments to be located and determine the space needed by each one. 2) Build a from-to matrix. This records the number of trips directly between each pair of areas, and can usually be found by observation over some representative period. 3) Use logical or sensible arguments to develop an initial schematic diagram for the layout (perhaps based on the current layout). 4) Determine a cost for this layout. This can be phrased in terms of total meters moved (= Σ movements * distance); kilogram-meters moved ( = Σ movements * distance * weight) or some other convenient measure. If this solution is acceptable go to Step 6, otherwise continue to Step 5. 5) Improve the initial layout. This may be done by trial and error, some algorithm (such as minimizing non-adjacent loads), or experience. Go back to Step 4. 6) Complete the block plan by including details of cost, additional constraints, preferred features, problems, and so on. Note: Difficulty Finding a suitable improving procedure for Step 5.

25 Block diagramming - Example Barko Inc. makes bark scalpers: 50 employees, 5 departments (cutting, sheet metal, machining, painting, assembly) Evaluate the current layout. Propose a new layout to minimize the nonadjacent load. Load Summary Chart Department Department

26 Example : Process Layout [Contd.] Load Summary Chart FROM/TO DEPARTMENT Department Composite Movements Composite Movements 2 l loads 4 l 5 60 loads 2 l loads 2 l 5 50 loads 1 l loads 3 l 4 40 loads 1 l loads 1 l 4 0 loads 3 l loads 1 l 5 0 loads

27 Example 1: Process Layout [Contd.] Load Summary Chart FROM/TO DEPARTMENT Department Load (two-way) Summary Chart FROM-TO DEPARTMENT Department

28 Example 1: Process Layout [Contd.] Load Summary Chart FROM/TO DEPARTMENT Department Composite Movements Composite Movements 2 l loads 4 l 5 60 loads 2 l loads 2 l 5 50 loads 1 l loads 3 l 4 40 loads 1 l loads 1 l 4 0 loads 3 l loads 1 l 5 0 loads

29 Example 1: Process Layout [Contd.] Load Summary Chart FROM/TO DEPARTMENT Department Grid 1 Composite Movements Composite Movements 2 l loads 4 l 5 60 loads 2 l loads 2 l 5 50 loads 1 l loads 3 l 4 40 loads 1 l loads 1 l 4 0 loads 3 l loads 1 l 5 0 loads

30 Load Summary Chart Example 1: Process Layout [Contd.] FROM/TO DEPARTMENT Department Grid Composite Movements Composite Movements 2 l loads 4 l 5 60 loads 2 l loads 2 l 5 50 loads 1 l loads 3 l 4 40 loads 1 l loads 1 l 4 0 loads 3 l loads 1 l 5 0 loads

31 Example 2: Process Layout A company wants to arrange the six departments of its factory in a way that will minimize interdepartmental material handling costs. They make an initial assumption (to simply the problem) that each department is 20x20 feet and that the building is 60 feet long and 40 feet wide. A from-to matrix of the current layout [the following figure shows the current layout] is given in the next slide. For this problem, the company assumes that a forklift carries all interdepartmental loads. The cost of moving one load between adjacent department is estimated to be $1. Moving a load between nonadjacent departments costs $2. With the above information, improve the given layout. Assembly Department 1 Receiving Department 4 Printing Department 2 Shipping Department 5 Machine shop Department 3 Testing Department 6

32 Example 2: Interdepartmental Flow of Parts

33 Example 2: Interdepartmental Flow Graph Showing Number of Weekly Loads

34 Example 2: Current Layout 1 Room 1 Room 2 Room 2 Assembly Department (1) Printing Department (2) Machine Shop Department (3) Receiving Department (4) Shipping Department (5) Testing Department (6) 40 Room 4 Room 5 Room 6 60

35 Schematic Diagram & Cost Solution Dept. Dept. Cost 1 3 $ $ $ $ $ $ $ $ $ 100 Total Cost $570 35

36 Solution Can we get a layout cheaper than $570? There are 6! or 720 possibilities. Putting departments 1 & 3 adjacent to each other gives a total cost of $480. Room 1 Room 2 Room 3 Dept. 1 Dept. 3 Dept. 2 Dept. 4 Dept. 5 Dept ft. Room 4 Room 5 Room 6 60 ft. 36

37 Schematic Diagram & Cost Solution Dept. Dept. Cost 1 2 $ $ $ $ $ $ $ $ $ 100 Total Cost $480 37

38 Example 2: Possible Layout 3 Room 1 Room 2 Room 2 Painting Department (2) Assembly Department (1) Machine Shop Department (3) Receiving Department (4) Shipping Department (5) Testing Department (6) 40 Room 4 Room 5 Room 6 60

39 EXERCISE One floor of a building has six office areas, which are all the same size. The current layout is shown in Figure. The company feels that a lot of unnecessary movements are made between areas and would like to reduce this by at least 25%. During a random period records were kept of the number of movements between areas and is given in Table. How might the layout of areas given in the figure be improved? Table: Number of Movements between areas Figure: Present Layout F R O M TO

40 Larger Layout Problems Method works fine for small problems Larger problems require software CRAFT-tries to minimize material handling costs Rearrange many large departments to reduce costs Human judgement calls impossible to computerize Numerical flow of items between departments Can be impractical to obtain Does not account for the qualitative factors that may be crucial to the placement decision 40

41 Process Layout: CRAFT (Computerized Relative Allocation of Facilities Technique Approach) I t is a heuristic program ; it uses a sim ple rules of thum b in m aking evaluations: "Com pare two departm ents at a tim e and exchange them if it reduces the total cost of the layout." I t does not guarantee an optim al solution CRAFT assum es the existence of variable path m aterial handling equipm ent such as forklift t rucks 41

42 Systematic Layout Planning : Relationship Diagramming Used when quantitative data is not available Replaced load sum m ary chart with m anagem ent inputs Muther s Grid [ Proposed by Richard Mut her] Coded as A,E,I,O,U and X. Shown in different t hickness of lines Goal: short heavy lines, thin lengthy lines, no zigzagged lines Denote location preferences with weighted lines 42

43 Example of Systematic Layout Planning: Importance of Closeness Value Closeness Line code Numerical weights A Absolutely necessary 16 E Especially important 8 I Important 4 O Ordinary closeness OK 2 U Unimportant 0 X Undesirable

44 Problem: A new office about to be opened, with six equally sized areas as shown in Figure. The importance that areas are close together is described by the following matrix. Suggest a layout for the office. Matrix shows the importance of areas Area A B C D E F A E/2 U/3 U/2 A/1 1/2 Area B C X/8 O/3 X/8 U/- U/- U/- 1/8 Figure: Six areas D E O/5 E/2 E/1 F A. Absolutely essential E. Especially important I. Important O. Ordinary importance U. Unimportant X. Undesirable 1. Sharing the same facilities; 2. Sharing the same staff; 3. Ease of supervision; 4. Ease of communications; 5. Sequence of operations in a process; 6. Customer contact; 7. Safety; 8. Unpleasant conditions; and so on 44

45 Solutions A. Absolutely essential E. Especially important I. Important O. Ordinary importance U. Unimportant X. Undesirable Solution B A F Area A B C D E A B E/2 Area C U/3 X/8 D U/2 O/3 X/8 E A/1 U/- U/- 1/8 O/5 F 1/2 U/- E/2 E/1 D E C F (a) B D A F (c) E C (b) 1. Sharing the same facilities; 2. Sharing the same staff; 3. Ease of supervision; 4. Ease of communications; 5. Sequence of operations in a process; 6. Customer contact; 7. Safety; 8. Unpleasant conditions; and so on45

46 Example of Systematic Layout Planning: Initial Relationship Diagram 1 I E 4 U 2 5 A Note here again, Depts. (1) and (2) are linked together, and Depts. (2) and (5) are linked together by multiple lines or required transactions. 3 U The number of lines here represent paths required to be taken in transactions between the departments. The more lines, the more the interaction between departments. 46

47 Relationship Diagramming Example Production Offices Stockroom Shipping and receiving Locker room Toolroom Example of Muther s Grid

48 Relationship Diagramming Example Production Offices Stockroom Shipping and receiving Locker room Toolroom O U A U O A O U O I X O E U A A E I Absolutely necessary Especially important Important O Okay U Unimportant X Undesirable

49 Relationship Diagramming Example Production Offices Stockroom Shipping and receiving Locker room Toolroom O U A U O A O U O I X O E U A A Absolutely necessary E Especially important I Important O Okay U Unimportant X Undesirable

50 Computerized Layout Solutions CRAFT - block diagramming PREP - multistory block diagram CORELAP - relationship diagramming ALDEP - multistory relationship diagramming Simulation 50

51 Service Layouts Usually process layouts due to customers needs Minimize flow of customers or paperwork Retailing tries to maximize customer exposure to products [Example is given in the next slide] Computer programs consider shelf space, demand, profitability Layouts must be aesthetically pleasing

52 Process Layout in Services Women s lingerie Shoes Housewares Women s dresses Cosmetics and jewelry Children s department Women s sportswear Entry and display area Men s department 52

53 Product-Oriented Layout Facility organized around product Design minimizes line imbalance Delay between work stations Types: Fabrication line; assembly line Product-Oriented Requirements Standardized product High production volume Stable production quantities Uniform quality of raw materials & components

54 Product-Oriented Layout - Assumptions Volume is adequate for high equipment utilization Product demand is stable enough to justify high investment in specialized equipment Product is standardized or approaching a phase of its life cycle that justifies investment in specialized equipment Supplies of raw materials and components are adequate and of uniform quality to ensure they will work with specialized equipment 54

55 A Product Layout In Out 55

56 Product (Line Flow) Layout Raw Materials Receiving & Storage Finished Goods Storage & Shipping Cut Plane Glue Flow Pack Sand Drill Turn Dry 56

57 Product-Oriented Layout Types Fabrication Line Assembly Line Builds components Uses series of machines Repetitive process Machine paced Balanced by physical redesign Assembles fabricated parts Uses workstation Repetitive process Paced by tasks Balanced by moving tasks 57

58 An Assembly Line Layout 58

59 Characteristics of Product Layouts Special-purpose equipment are used Changeover is expensive and lengthy Material flow approaches continuous Material handling equipment is fixed Operators need not be as skilled Little direct supervision is required Production time for a unit is relatively short In-process inventory is relatively low Planning, scheduling and controlling functions are relatively straight-forward 59

60 Comparison Of Product And Process Layouts PRODUCT LAYOUT PROCESS LAYOUT 1. Description Sequential arrangement Functional grouping of machines of machines 2. Type of Process Continuous, mass Intermittent, job shop production, mainly batch production, assembly mainly fabrication 3. Product Standardized Varied, made to stock made to order 4. Demand Stable Fluctuating 5. Volume High Low 6. Equipment Special purpose General purpose 7. Workers Limited skills Varied skills 60

61 Comparison Of Product And Process Layouts PRODUCT LAYOUT PROCESS LAYOUT 8. Inventory Low in-process, High in-process, high finished goods low finished goods 9. Storage space Small Large 10. Material Fixed path Variable path handling (conveyor) (forklift) 11. Scheduling Part of balancing Dynamic 12. Layout decision Line balancing Machine location 13. Goal Equalize work at Minimize material each station handling cost 14. Advantage Efficiency Flexibility 61

62 Comparison of Process and Product Layouts Process Layout (Job shop) Process flexibility Accommodates a wide range of products & services Easy to add new products Facilitates customization Volume flexibility Problems easily isolated Low initial cost Advantages General purpose equipment High operating cost Skilled labor Disadvantages High material handling costs Low equipment utilization High WIP inventory Long production lead times Wait-move-wait Competition for key resources High planning & control complexity Product Layout (Flow shop) Low operating cost Unskilled labor Mechanization and automation feasible Low WIP inventory Short production lead times Little waiting, low WIP Dedicated resources Low planning & control complexity Low process flexibility Process designed for specific product Adding/changing products requires significant changes to process Failure of one component of the system can shut down the entire system Not feasible for low volumes High initial cost Specialized equipment, facilities 62

63 Combination Layout (Typical) Finished Goods Storage & Shipping Raw Materials Receiving & Storage Work-in-process inventory (WIP) Assembly line (Product layout} Fabrication shop (Process layout) 63