Process Selection and Facility Layout

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Process Selection and Facility Layout
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Process types, process selection and automation
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Process Selection

• The ways organizations choose to produce or
• provide their goods and services.
• It involves choice of technology, type of
• processing, and so on.
• It influences

• Capacity planning
• Layout of facilities
• Equipment
• Design of work systems

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Process Selection and System Design
Facilities andEquipment
Forecasting
CapacityPlanning
Layout
Product service Design
ProcessSelection
WorkDesign
TechnologicalChange
Capacity is significantly impacted by process
selection and facility layout.
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Factors which influence process selection

• Variety
• How much
• Flexibility
• What degree
• Volume
• Expected output

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Process Types

• Project A non-repetitive set of activities
  directed toward a unique goal within a limited
  time frame
• Unique
• Examples Building a bridge, consulting
• Job shop provides unit or lot production or
  service with changeable specifications, according
  to customer needs
• Small scale
• Examples Machine shop, dentists office
• Batch Produces many different products in groups
  (batches)
• Low or Moderate volume
• Examples Bakeries, movie theaters, classrooms

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Process Types (Cont.)

• Repetitive provides one or a few highly
  standardized products or services
• High volumes of standardized goods or services
• Examples automobiles, computers, cafeteria, car
  wash
• Continuous produces highly uniform products or
  continuous services, often performed by machines
• Very high volumes of non-discrete goods
• Examples refineries, chemical plant, flour,
  sugar, electricity supplying and the internet

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Process Choice Affects Activities /Functions
Job Shop Batch Repetitive Continuous Projects
Cost estimation Difficult Somewhat routine Routine Routine Simple to complex
Cost per unit High Moderate Low Low Very high
Equipment used General purpose General purpose Special purpose Special purpose Varied
Fixed costs Low Moderate High Very high Very high
Variable costs High Moderate Low Very low High
Labor skills High Moderate Low Low to high Low to high
Marketing Promote capacities Promote capacities Semi-standard goods/ services Promote standardized goods/ services Promote standardized goods/ services Promote capacities
Scheduling Complex Moderately complex Routine Routine Complex, subject to change
Work-in-process inventory High High Low Low Varied
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Automation

• Automation Machinery that has sensing and
  control devices that enables it to operate
  automatically
• Standardized goods and services
• Examples
• Goods Automobile factories, semiconductors
• Services Package sorting, e-mail, on-line banking

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Automation Types

• Fixed automation
• Specialized equipment for a fixed sequence of
  operations
• Programmable automation
• Computer-aided design and manufacturing systems
  (CAD/CAM)
• Numerically controlled (NC) machines Machines
  that perform operations by following mathematical
  processing instructions.
• Robot A machine consisting of a mechanical arm,
  a power supply and a controller
• Flexible automation
• Manufacturing cell
• Flexible manufacturing systems
• Computer-integrated manufacturing (CIM)

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Flexible Manufacturing Systems

• FMS are more fully automated versions of cellular
  manufacturing A computer controls the transfer
  of parts from machine to machine as well as the
  start of work at each machine
• Produce a variety of similar products

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Classification of production systems and types of
layouts
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Facilities Layout

• The arrangement of departments, work centers,
  and equipment, with particular emphasis on
  movement of work (customers or materials) through
  the system.

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The Need for Layout Decisions
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The Need for Layout Design (Cont.)
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Basic Layout Types

• Product Layouts most helpful to repetitive
  processing
• Process Layouts used for irregular processing
• Fixed-position layouts used when projects
  require layouts
• Hybrid layouts combinations of these above types
• Cellular manufacturing
• Group technology
• Flexible Manufacturing Systems

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Product Layouts

• Product layout Layout that uses standardized
  processing operations to achieve smooth, fast,
  high-volume flow
• Made possible by highly standardized goods or
  services that allow highly standardized,
  repetitive processing
• The work is divided into a series of standardized
  tasks, permitting specialization of equipment and
  division of labor
• The large volumes handled by these systems
  usually make it economical to invest substantial
  sums of money in equipment and in job design.

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Production/Assembly Line
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U-Shaped Production Line
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Advantages of Product Layouts

• High rate of output
• Low unit cost
• Labor specialization
• Low material handling cost
• High utilization of labor and equipment
• Established routing and scheduling
• Routine accounting, purchasing and inventory
  control

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Disadvantages of Product Layouts

• Creates boring, repetitive jobs
• Poorly skilled workers may not maintain equipment
  or quality of output
• Fairly inflexible to changes in volume
• Highly inclined to shutdowns
• Needs preventive maintenance
• Individual incentive plans are impractical

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Process Layouts

• Process layouts Layouts that can handle various
  processing requirements
• The layouts feature departments or other
  functional groupings in which similar kinds of
  activities are performed
• Examples Machine shops usually have separate
  departments for milling, grinding, drilling, and
  so on
• Different products may present quite different
  processing requirements and sequences of
  operations

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Process Layout
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Comparison of Process and Product Layout
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Advantages of Process Layouts

• Can handle a variety of processing requirements
• Not particularly at risk to equipment failures
• Equipment used is less costly
• Possible to use individual incentive plans

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Disadvantages of Process Layouts

• In-process inventory costs can be high
• Challenging routing and scheduling
• Equipment utilization rates are low
• Material handling slow and inefficient
• Complexities often reduce span of supervision
• Special attention for each product or customer
• Accounting, inventory control and purchasing are
  more involved

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Fixed-Position Layouts

• Fixed-Position Layout Layout in which the
  product or project remains stationary, and
  workers, materials, and equipment are moved as
  needed
• Examples
• Large construction projects (buildings, power
  plants, dams)
• Shipbuilding, production of large aircraft
• Rockets used to launch space missions

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Combination Layouts

• The three basic layout types may be altered to
  satisfy the needs of a particular situation
• Examples
• Supermarket layouts primarily process layout,
  have fixed-path material-handling devices as well
  (roller-type conveyors and belt-type conveyors)
• Hospitals process layout, fixed-position layout
  as well (patient care)
• Off-line reworking (customized processing) of
  faulty parts in a product layout

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Cellular Layouts

• Cellular Production
• Layout in which machines are grouped into a cell
  that can process items that have similar
  processing requirements
• Group Technology
• The grouping into part families of items with
  similar design or manufacturing characteristics
• Design characteristics size, shape and function.
• Manufacturing or processing characteristics
  type and sequence of operations required.

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Line Balancing
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Design Product Layouts Line Balancing
Line Balancing is the process of assigning tasks
to workstations in such a way that the
workstations have approximately equal time
requirements.

• Tasks are grouped into manageable bundles and
  assigned to workstations with one or two
  operators
• Goal is to minimize idle time along the line,
  which leads to high utilization of labor and
  equipment
• Perfect balance is often impossible to achieve

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Cycle Time
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Example 1 Cycle Times
With 5 workstations, CT
1.0 minute.
Cycle time of a system longest processing time
in a workstation.
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Example 1 Cycle Times
With 1 workstation, CT
2.5 minutes.
Cycle time of workstation total processing
time in of tasks.
With 3 workstations, can CT 1.0 minute?
Workstation 1
Workstation 2
Workstation 3
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Output Capacity
Example 8 hours per day OT 8 x 60 480
minutes per day Cycle Time CT 1.0 min Output
OT/CT 480/1.0 480 units per day Cycle Time
CT 2.5 min Output OT/CT 480/2.5 192
units per day
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Cycle Time Determined by Desired Output
CT cycle time
D Desired output rate
Example 8 hours per day OT 8 x 60 480
minutes per day D 480 units per day CT OT/D
480/480 1.0 Minute
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Theoretical Minimum Number of Stations Required
å t

Nmin
CT

å
sum of task times

t

Nmin theoretical Minimum Number of
Workstations Required

Example 8 hours per day, desired output rate is
480 units per day CT OT/D 480/480 1.0
Minute Nmin ?t /CT 2.5/1.0 2.5 stations
3 stations
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Designing Process Layouts
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Designing Process Layout

• The main issue in design of process layouts
  concerns the relative positioning of the
  departments involved.
• Departments must be assigned to locations.
• The problem is to develop a reasonably good
  layout some combinations will be more desirable
  than others.

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Considerations

• Some departments may benefit from adjacent
  locations
• Sharing expensive tools or equipments.
• Some departments should be separated
• A lab with delicate equipment should not be
  located near a department that has equipment with
  strong vibrations.
• Sand blasting department and painting department.
• Flammable materials near a furnace.

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Measures of Effectiveness

• One advantage of process layouts satisfy a
  variety of processing requirements
• Customers or materials in these systems require
  different operations and different sequences of
  operations
• One of the major objectives in process layout is
  to minimize transportation cost, distance, or
  time
• This is usually accomplished by locating
  departments with relatively high
  interdepartmental work flow as close together as
  possible