Facility Layout 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 • for the flow patterns of materials and people around, into, and within buildings
Locate All Areas In and Around Buildings • Equipment • Work stations • Material storage • Rest/break areas • Utilities • Eating areas • Aisles • Offices
Characteristics of the Facility Layout Decision • Location of these various areas impacts 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
Characteristics of the Facility Layout Decision Layout decisions tend to be: • Infrequent • Expensive to implement • Studied and evaluated extensively • Long-term commitments
Materials Handling • The central focus of most manufacturing layouts is to minimize the cost of processing, transporting, and 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
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
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 • MH systems should be flexible • Mobile equipment should carry full loads
Materials Handling Material-Handling Equipment • Automatic transfer devices • Containers/pallets/hand carts • Conveyors • Cranes • Elevators • Pipelines • Turntables
Basic Layout Forms • Process • Product • Cellular • Fixed-Position • Hybrid
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)
Characteristics of Process Layouts • General-purpose equipment is used • Changeover is rapid • Material flow is intermittent • Material handling equipment is flexible • Operators are highly skilled
Characteristics of Process Layouts • Technical supervision is required • Planning, scheduling and controlling functions are challenging • Production time is relatively long • In-process inventory is relatively high
Product (Assembly Line) Layouts • Operations are arranged in the sequence required to make the product • Used when the operations system must handle a narrow variety of products in relatively high volumes • Operations and personnel are dedicated to producing one or a small number of products
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
Characteristics of Product Layouts • Little direct supervision is required • Planning, scheduling and controlling functions are relatively straight-forward • Production time for a unit is relatively short • In-process inventory is relatively low
Cellular Manufacturing Layouts • Operations required to produce a particular family (group) of parts are arranged in the sequence required to make that family • Used when the operations system must handle a moderate variety of products in moderate volumes
Characteristics of Cellular ManufacturingRelative to Process Layouts • Equipment can be less general-purpose • Material handling costs are reduced • Training periods for operators are shortened • In-process inventory is lower • Parts can be made faster and shipped more quickly
Characteristics of Cellular ManufacturingRelative to Product Layouts • Equipment can be less special-purpose • Changeovers are simplified • Production is easier to automate
Fixed-Position Layouts • Product remains in a fixed position, and the personnel, material and equipment come to it • Used when the product is very bulky, large, heavy or fragile
Hybrid Layouts • Actually, most manufacturing facilities use a combination of layout types. • 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.
New Trends in Manufacturing Layouts • Designed for quality • Designed for flexibility - to quickly shift to different product models or to different production rates • Cellular layout within larger process layouts • Automated material handling • U-shaped production lines
New Trends in Manufacturing Layouts • More open work areas with fewer walls, partitions, or other obstacles • Smaller and more compact factory layouts • Less space provided for storage of inventories throughout the layout
Planning Manufacturing Facility Layouts Two Categories of Software Tools • Computer aided design (CAD) • Allows 3-D, full-color views of facility design • Allows virtual walk-throughs • Ex. – ArchiCAD, AutoSketch, AutoCAD • Computer simulation • Can simulate proposed system layout in operation and measure its performance • Ex. – ProModel, VisFactory, SIMPROCESS
Planning Manufacturing Facility Layouts • Process and Warehouse Layouts • Product Layouts • Cellular Manufacturing Layouts
Planning Manufacturing Facility Layouts Process Layouts • Primary focus is on the efficient flow of materials • The wide variety of potential product routings through the facility can be evaluated using computer simulation • Warehouse Layouts • Primary focus is the fast storage and retrieval of inventory items • Decisions about aisle size/placement and location of each inventory item can be evaluated using computer simulation
Planning Manufacturing Facility Layouts Product Layouts • Primary focus is on the analysis of production lines • The goal of the production line analysis is to: • Determine how many workstations to have • Determine which tasks to assign to which workstation • Minimize the number of workers & machines used • Provide the required amount of capacity • Line balancing is a key part of the analysis
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
Planning Product Layouts Line Balancing Heuristics • Heuristic methods, based on simple rules, have been developed to provide good (not optimal) solutions to line balancing problems • Heuristic methods include: • Incremental utilization (IU) method • Longest-task-time (LTT) method • … and many others
Planning Product Layouts Incremental Utilization Method • Add tasks to a workstation in order of task precedence one at a time until utilization is 100% or is observed to fall • Then the above procedure is repeated at the next workstation for the remaining tasks • Pro – Appropriate when one or more task times is equal to or greater than the cycle time • Con – Might create the need for extra equipment
Planning Product Layouts Longest-Task-Time Method • Adds tasks to a workstation one at a time in the order of task precedence. • If two or more tasks tie for order of precedence, the one with the longest task time is added • Conditions for its use: • No task time can be greater than the cycle time • There can be no duplicate workstations
Planning Product Layouts Rebalancing a Production Line • Changes that can lead to production lines being out of balance or having insufficient/excess capacity are: • Changes in demand • Machine modifications • Variations in employee learning and training
Planning Cellular Manufacturing Layouts • Cell Formation Decision • Which machines are assigned to manufacturing cells • Which parts will be produced in each cell
Planning Cellular Manufacturing Layouts • Fundamental Requirements for Parts to be Made in Cells • Demand for the parts must be high enough and stable enough that moderate batch sizes of the parts can be produced periodically. • Parts must be capable of being grouped into parts families.
Planning Cellular Manufacturing Layouts More-Complex Issues to be Resolved • If all the parts cannot be cleanly divided between cells, how will we decide which are to be the exceptional parts? • If inadequate capacity is available to produce all the parts in cells, which parts should be made outside the cells?
Planning Cellular Manufacturing Layouts Cell Formation Procedure 1. Form the Parts-Machines Matrix. 2. Rearrange the Rows. • Place the machines that produce the same parts in adjacent rows. 3. Rearrange the Columns. • 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.
Characteristics of Services • There may be a diversity of services provided • There are three dimensions to the type of service: • Standard or custom design • Amount of customer contact • Mix of physical goods and intangible services • There are three types of service operations: • Quasi manufacturing • Customer-as-participant • Customer-as-product
Characteristics of Service Facility Layouts • The encounter between the customer and the service must be provided for. • The degree to which customer-related features must be provided varies with the amount of customer involvement and customer contact.
Planning Service Facility Layouts Quasi-Manufacturing Services • Several topics previously discussed under Manufacturing Layouts are relevant here: • Principles of material handling • CAD and simulation software • Line balancing
Planning Service Facility Layouts Customer-as-Participant & Customer-as-Product • An important element is providing for customer waiting lines • Amount of space needed for service counters and waiting customers • Placement of waiting lines in overall layout
Planning Service Facility Layouts • For many service operations, layouts are like process layouts in manufacturing • The departments of hospitals are grouped and located according to their processes • In some cases, closeness ratings are used to reflect the desirability of having one department near another
Wrap-Up: World-Class Practice • Strive for flexibility in layouts • Multi-job training of workers • Sophisticated preventive-maintenance programs • Flexible machines • Empowered workers trained in problem solving • Layouts small and compact • Services follow the above practices plus incorporate customer needs in design