EIN 4365 FACILITIES PLANNING AND MATERIAL HANDLING Lecture 10 Layout Planning Models and Design Algorithms Outline • • • Systematic Layout Planning (SLP) Procedure A constructive algorithm An improvement algorithm Facility Layout Procedures • Naddler’s Ideal System Approach (1961) • Immer’s Basic Steps (1950) • Apple’s Plant Layout Procedure (1977) • Reed’s Plant Layout Procedure (1961) • Muther’s Systematic Layout Planning (1961) Naddler’s Ideal System Approach The ideal system approach is based on the following hierarchical approach toward design: 1. Aim for the “theoretical ideal system.” 2. Conceptualize the “ultimate ideal system.” 3. Design the “technologically workable ideal system.” 4. Install the “recommended system.” Theoretical ideal system Ultimate ideal system Technologically workable system Recommended system Present system Immer’s Basic Steps Immer described the analysis of a layout problem as follows: “This analysis should be composed of three simple steps, which can be applied to any type of layout problem. These steps are: 1. Put the problem on the paper. 2. Show lines of flow. 3. Convert flow lines to machine lines. Apple’s Plant Layout Procedure Apple recommended that the following detailed sequence of steps be used in designing a plant layout. 1. Procure the basic data. 11. Determine storage requirements 2. Analyze the basic data. 12. Plan service and auxiliary activities. 3. Design the productive process. 13. Determine space requirements. 4. Plan the material flow pattern. 14. Allocate activities to total space. 5. Consider the general material handling plan. 15. Consider building type 6. Calculate equipment requirements. 16. Consider master layouts. 7. Plan individual work stations. 17. Evaluate, adjust and check the layout. 8. Select specific material handling equipment. 18. Obtain approval. 9. Coordinate groups of related operations. 19. Install the layout. 10. Design activity relationships. 20. Follow up on implementation of the layout. Reed’s Plant Layout Procedure In “planning for and preparing the layout,” Reed recommended that the following steps be taken in his “systematic plan of attack”: 1. Analyze the product to be produced. 2. Determine the process required to manufacture the product. 3. Prepare layout planning charts. 4. Determine work stations. 5. Analyze storage area requirements. 6. Establish minimum aisle widths. 7. Establish office requirements. 8. Consider personnel facilities and services. 9. Survey plant services. 10. Provide for future expansion. Systematic Layout Procedure (overview) Steps 1) Determine the flow between departments and form the relationship chart. 2) Develop a graphical representation of the relationship chart. 3) Determine the space requirement for each department. 4) Develop templates to represent each area. 5) Arrange the templates in the same fashion as the graphical representation. An Example Determine a good layout for a small manufacturing firm consisting of the following departments. Production (Pr) Warehouse (WH) Office (Of) Tool Room (TR) Food Services (FS) Maintenance (Mn) Locker Room (LR) Shipping/Receiving (SR) Warning! • This is not a precise method. Rather, it is an approach to help find a good layout. Any two people applying the approach, working independently, will probably not obtain the same layout. This problem is a design problem – not an analysis problem. Input data for the example From-to Chart Production Production Warehouse Shipping/Receiving 2000 300 Total flow between departments Production Production Warehouse Shipping/Receiving Warehouse 600 Shipping 100 600 2000 Warehouse Shipping 2600 400 2600 Relationship Chart Nodes Pr WH Production (Pr) A Warehouse (WH) Office (Of) Tool Room (TR) Food Services (FS) Maintenance (Mn) Locker Room (LR) Shipping/Receiving (SR) Of E O - TR A O Relationship chart priority codes A 4, E 3, I 2, O 1, U 0, X -1 - FS E O O - Mn A O O A LR E - SR Total E 24 A 11 O 7 10 5 O 11 3 9 Relationship Diagram • Objective: To arrange the nodes so that there is a minimum number of departments crossed when going from one to another. SR WH Of FS Pr LR Mn • Method: • 1) Select the dept. with the highest total, place it in the center • 2) Locate around it any dept’s that have 4-rel with it. • 3) Continue the procedure with each dept. in the diagram • 4) After all 4-rels are exhausted, if some departments are not in the diagram, continue with 3TR rels, then 2-rels and 1-rels until all departments are in the diagram. Space Requirements Office Area (sq. ft.) Production (Pr) 4800 Warehouse (WH) 3050 Office (Of) 2400 Toolroom (TR) 1150 Food Services (FS) 750 Maintenance (Mn) 1000 Locker Room (LR) 600 Shipping/Receiving (SR) 1900 Total 15,650 sq. ft. Blocks 12 8 6 3 2 2 2 5 40 If one grid = 20*20 = 400 ft2 Department Templates Pr FS LR Of Mn TR WH SR Space Relationship Diagram WH SR Of Pr TR FS Mn LR Layout SR Doing this well is more difficult than it looks. Expect a mess the first few times you try it. WH Of Pr TR FS LR Mn Rectilinear Distance • The rectilinear distance between (x,y) and (u,v) is |x – u| + |y – v|. It is used with right angle street and aisle networks. (x,y) o |y-v| o (u,v) |x-u| Effectiveness of the Layout SR WH Of Pr Nodes Pr WH Of TR FS (Pr) - 4*0 3*0 4*0 3*0 (WH) - 1*1 1*0 (Of) 1*0 (TR) - 1*3 (FS) TR (Mn) (LR) (SR) Mn LR SR Sum 4*0 3*0 3*0 0 1*3 4*0 4 1*3 1*0 3 4*0 3 0 1*4 4 0 0 FS LR Mn Total: 14 Effectiveness of an Alternative Layout SR WH Of Pr FS LR Nodes Pr WH Of TR FS (Pr) - 4*0 3*0 4*0 3*0 (WH) - 1*1 1*0 TR (Of) 1*0 (TR) - 1*3 (FS) (Mn) Mn (LR) (SR) Total: Mn LR SR Sum 4*0 3*0 3*0 0 1*2 4*0 3 1*3 1*0 3 4*0 3 0 1*4 4 0 0 13 Transformation to a Block Plan SR WH TR Of Pr Mn FS LR Second Example Proposed production plan: Product Sequence 1 A-C-D-A-F 2 B-A-C-D-F 3 E-B-C-A-F Space Requirements Dept. A B C D E F Area (sq. ft.) 200 300 400 300 100 500 Production 500 1000 300 Flow>1600 1200<Flow<1600 800<Flow<1200 250<Flow<800 Flow<250 Building: 30 ft.*60 ft. :A :E :I :O :U Relationship Chart Proposed production plan: Product Sequence 1 A-C-D-A-F 2 B-A-C-D-F 3 E-B-C-A-F Production 500 1000 300 Flow>1600 1200<Flow<1600 800<Flow<1200 250<Flow<800 Flow<250 I From-to chart A B C D A - 1500 B 1000 300 C 300 1500 D E 300 F E F 800 1500 - Total flow A B C A 1000 1800 B 300 C D E F A :A :E :I :O :U E O D E F 800 300 1500 - 1500 - Relationship Diagram Nodes A B C D E F A - B I - C A O - D E F I O E - E - E C D A F B Total 8 4 8 6 1 5 Space Requirement and Layout Dept. A B C D E F Area Blocks 200 2 300 3 400 4 300 3 100 1 500 5 E C D B A F A B C D E F E F F F F F B B A A D D B C C C C D E F 0 A - B 0 - C 0 0 - D 0 0 - 0 - Sum 0 0 0 0 0 0 Alternative Layout F E C F F F F D E A A C C D B B B C C D D B A F A B C D E F A - B 0 - C 0 0 - D E F 0 0 0 - 0 - Sum 0 0 0 0 0 0 Block Plan E F A B D C E F A B C D An Improvement Algorithm • A construction algorithm starts from scratch; however, improvement algorithms need an initial solution. Pairwise Exchange Method for Layout Improvement • Exchanging the locations of pairs of departments and calculating the benefit • Useful in redesigning an existing facility, which is typically triggered by: – – – – Addition of a new machine Changes in the product mix Decisions related to the contraction and expansion of storage areas Simple realization that the old layout is no longer adequate for its needs An Example Four departments of the same size. Initial Layout 1 2 Flow between departments: 1 2 3 4 1 10 15 20 2 10 5 3 5 4 - 3 4 TC = 10 (1) + 15(2) + 20 (3) + 10 (1) + 5 (2) + 5 (1) = 10 + 30 + 60 + 10 +10 + 5 = 125 Pairwise Exchange Four departments of the same size. Try Layout 3 2 Flow between departments: 3 2 1 4 3 5 2 10 5 1 15 10 20 4 - 1 4 TC = 10 (1) + 15(2) + 20 (1) + 10 (1) + 5 (2) + 5 (3) = 10 + 30 + 20 + 10 +10 + 15 = 95 Pairwise Exchange Four departments of the same size. Try Layout 2 3 Flow between departments: 2 3 1 4 2 10 5 3 5 1 10 15 20 4 - 1 4 TC = 10 (2) + 15(1) + 20 (1) + 10 (1) + 5 (3) + 5 (2) = 20 + 15 + 20 + 10 +15 + 10 = 90
