Facilities Planning and Design Course code: 1704031511 Spring 2017-2018 Required Text: Tompkins et al., (2003). Facilities Planning, 3rd or later Edition, John Wiley and Sons Inc. Students are encouraged to refer to the text book, and to take notes during the lectures.

Chapter 6 – Layout Planning Models and Design Algorithms Major Topics: Block layout vs detailed layout Decisions affecting space requirements and layouts Basic layout types Layout procedures: construction and improvement Algorithmic approaches Finalizing layout alternatives

Block layout vs detailed layout Shows relative locations and sizes of the departments Detailed layout: Shows the exact locations of all equipment, work benches, storage areas within each department Decisions affecting space requirements and layouts Centralized vs decentralized storage of WIP, tooling and supplies Fixed path vs variable path handling Unit load size Degree of automation used in handling Type of inventory and material control

Basic layout types Manufacturing Layouts: Depending on product volume-variety, facility layout can be classified as: Product Layout (Flow Shop) Product Family (group technology) Layout Process Layout (Job Shop) Fixed Location (Static) Layout Specialized Layouts: Warehouses Offices Large shopping centers

Layout procedures: construction and improvement Construction-type layout method: involves developing a new layout from scratch. Improvement-type method: generates layout alternatives based on an existing layout. Layout and material handling system should be designed simultaneously (construction-type). If existing layout is to be revised, the effectiveness of material handling system should be reviewed as well (improvement-type).

Procedures for plant layouts Apple’s plant layout procedure (20 steps) Reed’s plant layout procedure (10 steps) and the most important step is preparing the layout planning chart which includes: Flow process (O- T - S - I) Standard time for each operation Machine selection and balance Manpower selection and balance Material handling requirements Muther’s Systematic Layout Planning (SLP) procedure

Reed’s plant layout procedure - Layout planning chart

Muther’s Systematic Layout Planning (SLP) procedure

Relationship Diagram Muther’s Systematic Layout Planning (SLP) procedure

Space Relationship Diagram Muther’s Systematic Layout Planning (SLP) procedure

Develop layout alternatives Muther’s Systematic Layout Planning (SLP) procedure

Algorithmic approaches Algorithm approaches are based on relative placement of departments on the basis of: their “closeness ratings” – Relationship chart, qualitative data “material flow intensities” – From-to chart, quantitative data Both input forms can be converted to one another. Algorithms used to solve the layout problem: Pairwise exchange method Graph-based method CRAFT-Computerized Relative Allocation of Facilities Technique Mixed integer Programming (MIP) Simulated Annealing (SA) and Genetic Algorithms (GA)

Algorithmic approaches Minimize the total cost of movements between departments Maximize the total relationship Normalized Adjacency score Normalized Adjacency score with positive and negative flows

Discrete vs. continuous layout representation         Discrete vs. continuous layout representation

Examples of split and unsplit departments

Pairwise exchange method Procedure Calculate total cost for the existing layout For each iteration evaluate all feasible exchanges in the locations of department pairs Select the pair that results in the largest reduction in total cost Recompute the distance matrix each time an exchange is performed If the lowest total cost for your next iteration is worse than the total cost for the previous iteration, the procedure is terminated The method does not always guarantee yielding the optimal solution, only local optimum Final solution depends on the starting solution The procedure may cycle back to a previous alternative Symmetric layout may occur Pairwise exchange can be easily accomplished only if the departments are of the same size Easy to implement if department areas are the same

Pairwise exchange method Flow matrix Distance matrix Assume Cij = 1 for all i, j Iteration 0, z = 125 Iteration 1, z = 95 Iteration 2, z = 90 Flow matrix remains the same, distance matrix changes

Graph-based method Procedure Nodes represent departments, arcs represent relationship weights (flow) between departments Procedure 1.Select the department pair with the largest weight. Ties are broken arbitrarily 2.Select the third department to enter based on the largest sum of the weights with the first two departments 3.Pick the fourth department to enter on a face of the graph (a bounded region of a graph) 4.Determine an adjacency graph 5.Construct a corresponding block layout

Graph-based method Step 1

Graph-based method Step 2-3-4

Graph-based method Block layout generated from graph of step 4

CRAFT Input is From-To chart Department shapes are not restricted to rectangular ones or similar area

Initial CRAFT layout (z = 59,480) CRAFT Procedure 1.Determine department centroids. 2.Calculate rectilinear distance between centroids. 3.Calculate transportation cost for the layout. 4.Consider department exchanges of either equal area departments or departments sharing a common border. 5.Determine the estimated change in transportation cost of each possible exchange. 6.Select and implement the departmental exchange that offers the greatest reduction in transportation cost. 7. Repeat the procedure for the new layout until no interchange is able to reduce the transportation cost. Initial CRAFT layout (z = 59,480)

Intermediate CRAFT layout (z = 59,060) Final CRAFT layout (z = 56,670)

Finalizing layout alternatives (Massaging)