WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 1 IE 368: FACILITY DESIGN AND OPERATIONS MANAGEMENT Lecture Notes #5 Introduction to Facilities Layout

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 2 Facilities Layout Facilities layout is a design activity and as such there is often a lot of art (i.e., experience) and application- specific knowledge that must be utilized when developing a layout  Grocery store layout vs. department store layout  Layout of an engineering complex  Layout of an educational/research building  Layout of plants that produce different products Vehicle vs. computers

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 3 Facilities Layout (cont.) There are no recipes for the layout In reality, politics and other organizational considerations will place constraints on layouts All material presented related to layout design is decision support

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 4 Facilities Layout (cont.) Information needed to design a layout 1.What are the “blocks” or departments that constitute units or areas within a layout? 2.Building/facility footprint Exits/entrances/docks, etc. Columns, ceiling height, location of utilities. Other? 3.Flow measurement/Adjacency measurement 4.Space requirements Departments  Workstations, aisles, storage, meeting rooms, etc. Central storage Administration Etc.

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 5 Units or Areas Within a Layout Normally this is given as input data  Often will follow organizational and/or production system structure Examples  Engineering complexes – Various product development departments are given  Batch production system – Sheet metal press lines Various press line sizes are given Support functions must be included  Storage, admin/engineering offices, IT support, cafeterias, lockers, restrooms, conference rooms, etc

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 6 Building Footprint Often also given as input data Items of particular concern that affect flow in a facility  Location of shipping/receiving docks  Location of entrances/exits  Columns  Ceiling heights

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 7 Facilities Layout Measuring flow  Quantitative Appropriate when large volumes of material/people move between departments  Qualitative How important is adjacency to two departments? Often applied to the layout of office environments Other types of flow?  Sound  RF signals

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 8 Quantitative Flow Measurement Captured in a From-To chart Units are the number of trips of equal ease of movement per time unit  e.g., moving a large die is much more effort than moving a small bin of parts

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 9 Quantitative Flow Measurement (cont.) Terminology  From-To chart Symmetric travel paths are not necessarily assumed  Flow-Between chart Assumes symmetric travel so that only the upper or lower portion of the chart is needed  Only the total flow (in either direction) is needed

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 10 Construction of the Charts 1. List departments in rows and columns according to the general flow of jobs Helpful but not critical to list in this order 2. Translate movements of different jobs/items into equivalent materials handling moves 3. Translate production quantities/routings into materials handling moves between departments

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 11 Example 3.4 A firm produces three components. Components 1 and 2 have the same size and weight and are equivalent with respect to movement. Component 3 is almost twice as large and moving two units of components 1 or 2 is equivalent to moving one unit of component 3. The departments included in the facility are A, B, C, D, and E. The overall flow path is A-B-C-D-E. The quantities to be produced and the component routings are as follows: Construct a From-To chart

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 12 Example 3.4 – Solution ABCDE A-- B C D E

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 13 In-Class Exercise Suppose containers are moved one at a time  Produce a from-to chart with the number of moves between departments per week  Suppose moves of containers for product 1 and 2 have a fixed cost of $5 per move and moves of containers for products 3 and 4 cost $1 per move  Create a from-to chart with material movement cost per week

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 14 In-Class Exercise (cont.) ABCDE A-- B C D E ABCDE A B C D E

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 15 Construction of the Charts In the prior example, all flows occurred in lexicographic order (A-B, A-D), so only the upper triangular portion of the from-to chart had non-zero numbers

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 16 Qualitative Flow Measurement Captured in what is called an Activity Relationship Chart The criticality of department adjacency is captured on the following scale:  A – Absolutely necessary  E – Especially important  I – Important  O – Ordinary closeness OK  U – Unimportant  X – Undesirable Assessed through interviews and meetings Can also construct activity relationship charts from flow data by equating flow amounts to activity codes

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 17 Example

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 18 Determining Space Requirements Often very political Not independent of scheduling/inventory control, storage and delivery methods  Can generate multiple alternatives if certain details are not established Approaches – Departmental requirements  Use historical data, data from other facilities  Ground-Up approach Workstation requirements  Departmental requirements Apply a combination of checklists, reviews with personnel

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 19 Determining Space Requirements (cont.) Equipment considerations related to space  Equipment footprint  Machine travel  Room for materials in process (e.g., long bar stock)  Room for equipment maintenance  Room for plant services  … Where to get information  Equipment manufacturers  Current installation  Operator interviews  …

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 20 Determining Space Requirements (cont.) Materials related space  Receiving and storing (plant, department, WS)  Work-In-Process  Shipping, finished goods (plant, department, WS)  Storing/removal of waste  Tools, supplies, manuals, other equipment  … Aisle space  See tables 3.3, 3.4 – General aisle space allowances based on flow and size of loads moved  See next slides

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 21 Personnel Space at a Workstation More detailed design/layout Addressed in ergonomics/human factors Guidelines and regulations exist  U.S. Department of Labor Occupational Safety & Health Administration People available to help with compliance  U.S. Department of Health and Human Services – Center for Disease Control and Prevention: National Institute for Occupational Safety and Health

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 22 Generating Layout Alternatives Objective  Develop a good or optimal block layout Block layout  A two dimensional top down view arrangement of departments in a facility  Departments are represented as rectangles (or shapes constructed from rectangles) with the relative area of the department captured by the size of the rectangle Office FabPaint Stores Assembly Maint Sup

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 23 Layout Levels From:

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 24 Generating Layout Alternatives Procedures  Construction procedures “Greenfield” layout, the layout of a new facility  Improvement procedures Changes/ improvements to existing facilities Not a critical distinction

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 25 Systematic Layout Planning (SLP) A qualitative method 1.Use a from-to or flow-between chart and/or an activity relationship chart, and space requirements to create a relationship diagram 2.Next, use the relationship diagram to create a space relationship diagram 3.The space relationship diagram is used to generate layout alternatives in the form of block layouts

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 26 SLP Example

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 27 SLP Example (cont.)

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 28 SLP Example (cont.)

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 29 SLP Example – Problem 6.7 Four depts. are to be located on a 600’ x 1000’ bldg. The expected personnel traffic flows and area requirements for departments are shown in the tables below a.Develop a block layout design using SLP Dept.ABCD A B C D Dept.Dimen. A200’x200’ B400’x400’ C600’x600’ D200’x200’

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 30 SLP Example – Problem 6.7 (cont.) 1) Construct a Flow-Between Chart 2) Rank the department pairs in order of greatest two-way flow ABCD A-- B C D

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 31 SLP Example – Problem 6.7 (cont.) 3) Create an Activity-Relationship diagram 4) Create a Space-Relationship diagram

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 32 SLP – In Class Example 4) Generate layout options Dept.Dimen. A200’x200’ B400’x400’ C600’x600’ D200’x200’

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 33 Computer-Aided Layout Computer-aided layout supports layout design  Generate many layout alternatives in a short time  Helps conduct what if and sensitivity analysis  Modeling the problem helps understand the system perspective Commercial software  Most algorithms have not yet been commercialized although they are available as research code and used by consultants  Educational software is available We will use one package

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 34 Computer-Aided Layout (cont.) Inputs 1.From-To chart and/or 2.Activity relationship chart  You may have the flexibility to map the A,E,I,O,U,X scale to different numerical scales  Can change results by changing the scaling  Can have negative values for relationships (e.g., X) 3.Usually, the building footprint  May be restricted to a rectangular footprint

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 35 Computer-Aided Layout (cont.) Layout development criteria  When constructing a layout, an algorithm implemented on a computer needs specific criteria to compare alternative layouts  These criteria may differ depending on the form of input data characterizing flow/relationships  The criteria must be computable (quantitative) and is referred to as the objective function of the layout problem

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 36 Computer-Aided Layout (cont.) From-to chart as input data  The objective will be to construct a layout to minimize required movement costs over a specific time period

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 37 Computer-Aided Layout (cont.) The objective function can be expressed as: This is called a distance-based objective function The f ij and c ij are input data If the c ij = 1 for all i and j, z = total travel distance per time period

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 38 Distance Measure The d ij ’s are normally rectilinear centroid to centroid distance The d ij ’s change as a function of department location and shape Rectilinear distance ’s

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 39 Centroids Centroid  Center of gravity or mass

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 40 Centroids (cont.)

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 41 In-class Exercise Find the centroid

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 42 In-class Exercise (cont.)

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 43 Computer-Aided Layout Activity relationship chart as input  The activity relationship between departments i and j must first be quantified to get f ij, which represents the relationship strength on some numerical scale One possible objective function:

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 44 Computer-Aided Layout (cont.) This is called an adjacency based objective Since the numerical scale is arbitrary, another objective function is often used  Called an efficiency rating (or normalized adjacency score)  It is a relative measure of a layout with respect to the best (sometimes not possible) objective function value

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 45 Computer-Aided Layout (cont.) No negative f ij values Negative f ij values

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 46 Computer-Aided Layout (cont.) Facility Layout: Flows:Adjacency: A E UX O X X 12 =X 23 =X 34 = X 13 =X 24 = X 14 =

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 47 In-class Exercise Evaluate the efficiency rating and total travel distance for the layout generated in the SLP example Dept.ABCD A B C D Dept.Dimen. A200’x200’ B400’x400’ C600’x600’ D200’x200’

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 48 In-class Exercise (cont.) ABCD A -- B C D

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 49 “Optimizing” a Layout Finding the optimal layout that minimizes either of the objective functions described is a very difficult problem (computationally) General methods for exploring the space of layouts have been applied  Pairwise exchange method A general approach used to improve an existing layout  Graph-based method  Other methods Metaheuristics Covered in IE 425

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 50 Pairwise Exchange Method This is a heuristic search procedure  Not guaranteed to find the optimal layout (except under certain circumstances) In general, this is a method that should be computerized but is applicable by hand in small examples We will examine an example with the cost of material movement used as a criteria to evaluate layouts (distance based objective)  If all costs are the same (=1), this is total distance  Activity relationship charts and adjacency based objectives can be used

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 51 Pairwise Exchange Method (cont.) Algorithm 1.“Layout” = Initial layout. “Cost” = Distance based cost for “Layout” 2.For each possible pairwise exchange of departments in “Layout”, calculate the total distance based cost 3.If the lowest cost from the pairwise exchanges is > “Cost”, go to 4  Else “Layout” = Layout with the lowest cost “Cost” = Lowest cost from step 2  Go to 2 4.End with “Layout” and “Cost” as the final layout and cost

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 52 Pairwise Exchange Method (cont.) Example from text  Assume distances are centroid to centroid  Assume travel from dept i to j is symmetric

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 53 Pairwise Exchange Method (cont.) TC 2134 (1-2) = 10(1) + 15(1) + 20(2) + 10(2) + 5(3) + 5(1) = 105 TC 3214 (1-3) = 10(1) + 15(2) + 20(1) + 10(1) + 5(2) + 5(3) = 95 TC 4231 (1-4) = 10(2) + 15(1) + 20(3) + 10(1) + 5(1) + 5(2) = 120 TC 1324 (2-3) = 10(2) + 15(1) + 20(3) + 10(1) + 5(1) + 5(2) = 120 TC 1432 (2-4) = 10(3) + 15(2) + 20(1) + 10(1) + 5(2) + 5(1) = 105 TC 1243 (3-4) = 10(1) + 15(3) + 20(2) + 10(2) + 5(1) + 5(1) = 125 (a) Iteration

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 54 Pairwise Exchange Method (cont.) TC 3124 (1-2) = 10(1) + 15(1) + 20(2) + 10(2) + 5(1) + 5(3) = 105 TC 1234 (1-3) = 10(1) + 15(2) + 20(3) + 10(1) + 5(2) + 5(1) = 125 TC 3241 (1-4) = 10(2) + 15(3) + 20(1) + 10(1) + 5(1) + 5(2) = 110 TC 2314 (2-3) = 10(2) + 15(1) + 20(1) + 10(1) + 5(3) + 5(2) = 90 TC 3412 (2-4) = 10(1) + 15(2) + 20(1) + 10(3) + 5(2) + 5(1) = 105 TC 4213 (3-4) = 10(1) + 15(1) + 20(2) + 10(2) + 5(1) + 5(3) = 105 (b) Iteration

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 55 Pairwise Exchange Method (cont.) TC 1324 (1-2) = 10(2) + 15(1) + 20(3) + 10(1) + 5(1) + 5(2) = 120 TC 2134 (1-3) = 10(1) + 15(1) + 20(2) + 10(2) + 5(3) + 5(1) = 105 TC 2341 (1-4) = 10(3) + 15(2) + 20(1) + 10(1) + 5(2) + 5(1) = 105 TC 3214 (2-3) = 10(1) + 15(2) + 20(1) + 10(1) + 5(2) + 5(3) = 95 TC 4312 (2-4) = 10(1) + 15(1) + 20(2) + 10(2) + 5(3) + 5(1) = 105 TC 2413 (3-4) = 10(2) + 15(1) + 20(1) + 10(3) + 5(1) + 5(2) = 100 (b) Iteration

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 56 Graph-based Method Often applied when using an adjacency-based objective A method that uses a graph (nodes connected by arcs) to represent departments and their adjacencies to other departments  Departments = nodes  If an arc connects two departments, they are adjacent Arcs have values that represent adjacency relationships  Finding the best layout amounts to finding the best graph

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 57 Graph-based Method (cont.)

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 58 Graph-based Method (cont.) Procedure for generating an adjacency graph 1.Find the highest valued adjacency relationship as the starting nodes connected by an arc (break ties randomly) 2.The third department selected will have the largest total relationship value with the two departments selected in step 1 3.The next departments to enter are selected one at a time based on the highest total relationship values added when the department is placed on the “face” of the existing graph  A face is a region bounded by arcs of the graph

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 59 Graph-based Method (cont.)

WINTER 2012IE 368. FACILITY DESIGN AND OPERATIONS MANAGEMENT 60 Graph-based Method (2) A department block layout still needs to be constructed from the graph in a manner similar to SLP