Layout Decisions

Facility layout: the process of determining placement of departments, workgroups within departments, workstations, machines, and stock-holding points within a facility

This process requires the following inputs:

Specification of the objectives used to evaluate the design

Estimates of product or service demand

Processing requirements

Space requirements for the elements

Space availability within the facility

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Basic Production Layout Formats

Workcenter (job-shop or functional layout)

Similar equipment are grouped together.

Assembly line (flow-shop layout)

Work processes are arranged according to the steps by which the product is made.

Manufacturing cell

Dissimilar machines are grouped to work on similar products.

Project layout

Product remains at one location.

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Workcenters

Given

The flow (number of moves) to and from all departments

The cost of moving from one department to another

The existing or planned physical layout of the plant

Determine

The “best” locations for each department, where best means maximizing flow, which minimizes costs

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Example 8.1: Interworkcenter Flow Graph with Number of Annual Movements

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Assembly Line

Assembly line: progressive assembly linked by some material handling device

Some form of pacing is present and the allowable processing time is equivalent for all workstations

Important differences:

Material handling devices

Line configuration

Pacing

Product mix

Workstation characteristics

Length

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Assembly-Line Design

Workstation cycle time: a uniform time interval in which a moving conveyor passes a series of workstations

Also the time between successive units coming off the line

Assembly-line balancing: assigning all tasks to a series of workstations so that each workstation has no more than can be done in the workstation cycle time

Precedence relationship: the order in which tasks must be performed in the assembly process

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Assembly-Line Balancing

Specify the sequential relationships among tasks.

Determine the required workstation cycle time.

Determine the theoretical minimum number of workstations.

Select a primary and secondary assignment rule.

Assign tasks.

Evaluate the efficiency of the balance.

Rebalance if needed.

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Task Splitting

Split the task

Share the task

Use parallel workstations

Use a more skilled worker

Work overtime

Redesign

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Flexible Line Layouts

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Problem – operators trapped in “cages” prevents sharing work among them

Solution – remove barriers so operators can trade work and operators can be added or removed as needed

Flexible Line Layouts

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Problem – operators “birdcaged” with no opportunity to share work or add third operator

Solution – operators can help each other and third operator can be added if needed

Flexible Line Layouts

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Problem – straight line is difficult to balance

Solution – U-shaped line gives better operator access and may reduce need for operators

Mixed-Model Line Balancing

Most factories produce a number of different products.

Inventory can be reduced by building some of each product during every period (e.g., day, week, etc.).

Mixed-model line balancing is one means of scheduling this varied production.

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Developing a Manufacturing Cell

Grouping parts into families that follow a common sequence of steps

Identifying dominant flow patterns of parts families as a bases for location of processes

Physically grouping machines and processes into cells

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Example: Original Workcenter Layout

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Example: Routing Matrix Based upon Flow of Parts

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Example: Reallocating Machines to Form Cells

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Manufacturing Cell Benefits

Better human relations

Improved operator expertise

Less in-process inventory and material handling

Faster production setup

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Project Layout

Is characterized by a relatively low number of production units.

Visualize the product as the hub of a wheel with materials and equipment arranged concentrically around the production point.

A high degree of task ordering is common.

To the extent that this precedence determines production stages, a project layout might be developed by arranging materials according to their technological priority.

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Retail Service Layout

Goal—maximize net profit per square foot of floor space

Servicescapes

Ambient conditions

Background characteristics, such as noise

Spatial layout and functionality

Planning the circulation path of customers and grouping merchandise

Signs, symbols, and artifacts

Parts of the service that have social significance

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Alternative Store Layouts

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Marketing Research and Retail Layout

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People in supermarkets tend to follow a perimeter pattern in their shopping behavior. Placing high-profit items along the walls of a store will enhance their probability of purchase.

Sale merchandise placed at the end of an aisle in supermarkets almost always sells better than the same sale items placed in the interior portion of an aisle.

Credit and other non-selling departments that require customers to wait for the completion of their services should be placed either on upper floors or in “dead” areas.

In department stores, locations nearest the store entrances and adjacent to front window displays are most valuable in terms of sales potential.

Office Layout

More open offices

Low divider walls

Size and orientation of desks indicates importance of people behind them

ServiceMaster (A major janitorial firm) places its

know-how room (tools , manuals) at the center

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