Facility Layout: Manufacturing and Services

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

Manufacturing Facility Layouts

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 Procedure1. 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 Procedure1. 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.

Service Facility Layouts

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