slide 0 of 96 chapter 8 facility layout: manufacturing and services manufacturing and services honey...

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Chapter 8Chapter 8

Facility Layout:Facility Layout:

Manufacturing and ServicesManufacturing and Services

Honey Arora

MBA – III

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OverviewOverviewOverviewOverview

IntroductionIntroduction Manufacturing Facility LayoutsManufacturing Facility Layouts Analyzing Manufacturing Facility LayoutsAnalyzing Manufacturing Facility Layouts Service Facility LayoutsService Facility Layouts Wrap-Up: What World-Class Producers DoWrap-Up: What World-Class Producers Do

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IntroductionIntroductionIntroductionIntroduction

Facility layoutFacility layout means planning: means planning: for the location of all machines, utilities, employee for the location of all machines, utilities, employee

workstations, customer service areas, material workstations, customer service areas, material storage areas, aisles, restrooms, lunchrooms, storage areas, aisles, restrooms, lunchrooms, internal walls, offices, and computer roomsinternal walls, offices, and computer rooms

for the flow patterns of materials and people for the flow patterns of materials and people around, into, and within buildingsaround, into, and within buildings

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Locate All Areas In and Around BuildingsLocate All Areas In and Around BuildingsLocate All Areas In and Around BuildingsLocate All Areas In and Around Buildings

EquipmentEquipment Work stationsWork stations Material storageMaterial storage Rest/break areasRest/break areas UtilitiesUtilities Eating areasEating areas AislesAisles OfficesOffices

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Characteristics of the Facility Layout DecisionCharacteristics of the Facility Layout DecisionCharacteristics of the Facility Layout DecisionCharacteristics of the Facility Layout Decision

Location of these various areas impacts the flow Location of these various areas impacts the flow through the system.through the system.

The layout can affect productivity and costs The layout can affect productivity and costs generated by the system.generated by the system.

Layout alternatives are limited byLayout alternatives are limited by the amount and type of space required for the the amount and type of space required for the

various areasvarious areas the amount and type of space availablethe amount and type of space available the operations strategythe operations strategy

. . . more. . . more

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Characteristics of the Facility Layout DecisionCharacteristics of the Facility Layout DecisionCharacteristics of the Facility Layout DecisionCharacteristics of the Facility Layout Decision

Layout decisions tend to be:Layout decisions tend to be: InfrequentInfrequent Expensive to implementExpensive to implement Studied and evaluated extensivelyStudied and evaluated extensively Long-term commitmentsLong-term commitments

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Objectives of the Lay out StrategyObjectives of the Lay out Strategy

Develop an economical layout which will meet the Develop an economical layout which will meet the requirements of:requirements of:

product design and volume (product strategy)product design and volume (product strategy) Process equipment and capacity (process strategy)Process equipment and capacity (process strategy) quality of work life (human resource strategy)quality of work life (human resource strategy) building and site constraints (location strategy)building and site constraints (location strategy)

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Requirements of a Good LayoutRequirements of a Good Layout

A good layout requires:A good layout requires: an understanding of capacity & space requirementsan understanding of capacity & space requirements selection of appropriate material handling equipmentselection of appropriate material handling equipment decisions regarding environment and aestheticsdecisions regarding environment and aesthetics identification and understanding of the requirements identification and understanding of the requirements

for information flowfor information flow identification of the cost of moving between the identification of the cost of moving between the

various work areasvarious work areas

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Inputs to the Layout DecisionInputs to the Layout Decision

1. Specification of objectives of the system in terms of 1. Specification of objectives of the system in terms of output and flexibility.output and flexibility.

2. Estimation of product or service demand on the 2. Estimation of product or service demand on the system.system.

3. Processing requirements in terms of number of 3. Processing requirements in terms of number of operations and amount of flow between departments operations and amount of flow between departments and work centers.and work centers.

4. Space requirements for the elements in the layout.4. Space requirements for the elements in the layout.

5. Space availability within the facility itself5. Space availability within the facility itself ..

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Steps in Developing a Process Oriented LayoutSteps in Developing a Process Oriented Layout

Construct a “from-to matrix”Construct a “from-to matrix” Determine space requirements for each departmentDetermine space requirements for each department Develop an initial schematic diagramDevelop an initial schematic diagram Determine the cost of this layoutDetermine the cost of this layout By trial-and error (or more sophisticated means), try to By trial-and error (or more sophisticated means), try to

improve the initial layoutimprove the initial layout Prepare a detailed plan that evaluates factors in Prepare a detailed plan that evaluates factors in

addition to transportation costaddition to transportation cost

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Warehouse & Storage LayoutWarehouse & Storage LayoutGeneral Cost CurveGeneral Cost Curve

0

20

40

60

80

100

120

10 20 30 40 50 60 70 80 90 100

Warehouse Density

Line 1

Line 2

Line 3The best warehouse layout is wheretotal costs are at a minimum

Material handling cost(mostly variable) Costs include: Equipment Damage Position & Find Investment

Material storage cost(mostly fixed) Costs include: Land & building Building & insurance

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Manufacturing Facility LayoutsManufacturing Facility Layouts

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Basic Layout FormsBasic Layout FormsBasic Layout FormsBasic Layout Forms

ProcessProcess ProductProduct CellularCellular Fixed positionFixed position HybridHybrid

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Process (Job Shop) LayoutsProcess (Job Shop) LayoutsProcess (Job Shop) LayoutsProcess (Job Shop) Layouts

Equipment that perform similar processes are Equipment that perform similar processes are grouped togethergrouped together

Used when the operations system must handle a wide Used when the operations system must handle a wide variety of products in relatively small volumes (i.e., variety of products in relatively small volumes (i.e., flexibility is necessary)flexibility is necessary)

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Characteristics of Process LayoutsCharacteristics of Process LayoutsCharacteristics of Process LayoutsCharacteristics of Process Layouts

General-purpose equipment is usedGeneral-purpose equipment is used Changeover is rapidChangeover is rapid Material flow is intermittentMaterial flow is intermittent Material handling equipment is flexibleMaterial handling equipment is flexible Operators are highly skilledOperators are highly skilled . . .. . . moremore

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Characteristics of Process LayoutsCharacteristics of Process LayoutsCharacteristics of Process LayoutsCharacteristics of Process Layouts

Technical supervision is requiredTechnical supervision is required Planning, scheduling and controlling functions are Planning, scheduling and controlling functions are

challengingchallenging Production time is relatively longProduction time is relatively long In-process inventory is relatively highIn-process inventory is relatively high

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Product (Assembly Line) LayoutsProduct (Assembly Line) LayoutsProduct (Assembly Line) LayoutsProduct (Assembly Line) Layouts

Operations are arranged in the sequence required to Operations are arranged in the sequence required to make the productmake the product

Used when the operations system must handle a Used when the operations system must handle a narrow variety of products in relatively high volumesnarrow variety of products in relatively high volumes

Operations and personnel are dedicated to producing Operations and personnel are dedicated to producing one or a small number of productsone or a small number of products

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Characteristics of Product LayoutsCharacteristics of Product LayoutsCharacteristics of Product LayoutsCharacteristics of Product Layouts

Special-purpose equipment are usedSpecial-purpose equipment are used Changeover is expensive and lengthyChangeover is expensive and lengthy Material flow approaches continuousMaterial flow approaches continuous Material handling equipment is fixedMaterial handling equipment is fixed Operators need not be as skilledOperators need not be as skilled . . .. . . moremore

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Characteristics of Product LayoutsCharacteristics of Product LayoutsCharacteristics of Product LayoutsCharacteristics of Product Layouts

Little direct supervision is requiredLittle direct supervision is required Planning, scheduling and controlling functions are Planning, scheduling and controlling functions are

relatively straight-forwardrelatively straight-forward Production time for a unit is relatively shortProduction time for a unit is relatively short In-process inventory is relatively lowIn-process inventory is relatively low

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Cellular Manufacturing (CM) LayoutsCellular Manufacturing (CM) LayoutsCellular Manufacturing (CM) LayoutsCellular Manufacturing (CM) Layouts

Operations required to produce a particular family Operations required to produce a particular family (group) of parts are arranged in the sequence required (group) of parts are arranged in the sequence required to make that familyto make that family

Used when the operations system must handle a Used when the operations system must handle a moderate variety of products in moderate volumesmoderate variety of products in moderate volumes

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Characteristics of CMCharacteristics of CMRelative to Process LayoutsRelative to Process Layouts

Characteristics of CMCharacteristics of CMRelative to Process LayoutsRelative to Process Layouts

Equipment can be less general-purposeEquipment can be less general-purpose Material handling costs are reducedMaterial handling costs are reduced Training periods for operators are shortenedTraining periods for operators are shortened In-process inventory is lowerIn-process inventory is lower Parts can be made faster and shipped more quicklyParts can be made faster and shipped more quickly

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Characteristics of CMCharacteristics of CMRelative to a Product LayoutRelative to a Product Layout

Characteristics of CMCharacteristics of CMRelative to a Product LayoutRelative to a Product Layout

Equipment can be less special-purposeEquipment can be less special-purpose Changeovers are simplifiedChangeovers are simplified Production is easier to automateProduction is easier to automate

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Fixed-Position LayoutsFixed-Position LayoutsFixed-Position LayoutsFixed-Position Layouts

Product remains in a fixed position, and the Product remains in a fixed position, and the personnel, material and equipment come to itpersonnel, material and equipment come to it

Used when the product is very bulky, large, heavy or Used when the product is very bulky, large, heavy or fragile fragile

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Hybrid LayoutsHybrid LayoutsHybrid LayoutsHybrid Layouts

Actually, most manufacturing facilities use a Actually, most manufacturing facilities use a combination of layout types.combination of layout types.

An example of a hybrid layout is where departments An example of a hybrid layout is where departments are arranged according to the types of processes but are arranged according to the types of processes but the products flow through on a product layout.the products flow through on a product layout.

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New Trends in Manufacturing LayoutsNew Trends in Manufacturing LayoutsNew Trends in Manufacturing LayoutsNew Trends in Manufacturing Layouts

Designed for quality and flexibilityDesigned for quality and flexibility Ability to quickly shift to different product models or Ability to quickly shift to different product models or

to different production ratesto different production rates Cellular layout within larger process layoutsCellular layout within larger process layouts Automated material handlingAutomated material handling U-shaped production linesU-shaped production lines . . . more. . . more

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New Trends in Manufacturing LayoutsNew Trends in Manufacturing LayoutsNew Trends in Manufacturing LayoutsNew Trends in Manufacturing Layouts

More open work areas with fewer walls, partitions, or More open work areas with fewer walls, partitions, or other obstaclesother obstacles

Smaller and more compact factory layoutsSmaller and more compact factory layouts Less space provided for storage of inventories Less space provided for storage of inventories

throughout the layoutthroughout the layout

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Process LayoutsProcess Layouts Product LayoutsProduct Layouts Cellular LayoutsCellular Layouts

Analyzing Manufacturing Facility LayoutsAnalyzing Manufacturing Facility LayoutsAnalyzing Manufacturing Facility LayoutsAnalyzing Manufacturing Facility Layouts

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Process LayoutProcess Layout

What factors might we consider when determining What factors might we consider when determining the locations of process areas, or departments? the locations of process areas, or departments?

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Designing and Analyzing a Process LayoutDesigning and Analyzing a Process LayoutDesigning and Analyzing a Process LayoutDesigning and Analyzing a Process Layout

Group like processes together into departments or Group like processes together into departments or work centerswork centers

Determine where in the building these departments Determine where in the building these departments will be located relative to one anotherwill be located relative to one another

The objective is to arrange the departments so that The objective is to arrange the departments so that some criterion such as material-handling cost is some criterion such as material-handling cost is minimizedminimized

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Approaches to Process Layout DesignApproaches to Process Layout DesignApproaches to Process Layout DesignApproaches to Process Layout Design

Operations sequence analysisOperations sequence analysis Block diagram analysisBlock diagram analysis Load-distance analysisLoad-distance analysis Computer analysisComputer analysis

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Operations Sequence AnalysisOperations Sequence AnalysisOperations Sequence AnalysisOperations Sequence Analysis

Inputs requiredInputs required an existing or proposed arrangement of an existing or proposed arrangement of

departmentsdepartments a projection of the traffic or flow that will take a projection of the traffic or flow that will take

place between one department and each of the place between one department and each of the other departments during some time period - this is other departments during some time period - this is usually displayed as an interdepartmental flow usually displayed as an interdepartmental flow matrixmatrix

. . .. . . moremore

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Departments are represented by nodes (circles)Departments are represented by nodes (circles) Using the interdepartmental flow information, flows Using the interdepartmental flow information, flows

between adjacent departments are represented by between adjacent departments are represented by solid lines. Dashed lines represent traffic between solid lines. Dashed lines represent traffic between nonadjacent departments. The projected volumes are nonadjacent departments. The projected volumes are written above the appropriate lines.written above the appropriate lines.


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Departments (circles) are moved with the objective of Departments (circles) are moved with the objective of reducing the amount of nonadjacent flow.reducing the amount of nonadjacent flow.

This proceeds until no further improvement can be This proceeds until no further improvement can be foundfound

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Block Diagram AnalysisBlock Diagram AnalysisBlock Diagram AnalysisBlock Diagram Analysis

This approach follows the operations sequence This approach follows the operations sequence analysis and is an effort to make the solution more analysis and is an effort to make the solution more realisticrealistic

Each department is represented by a square the Each department is represented by a square the relative size of the departmentrelative size of the department

Shapes of the squares are altered to fit into the Shapes of the squares are altered to fit into the boundaries of the building while retaining the same boundaries of the building while retaining the same areas and relative position found in the operations areas and relative position found in the operations sequence analysissequence analysis

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Load-Distance AnalysisLoad-Distance AnalysisLoad-Distance AnalysisLoad-Distance Analysis

A way of quantitatively comparing alternative A way of quantitatively comparing alternative process layoutsprocess layouts

InputsInputs Alternative block layouts which will provide the Alternative block layouts which will provide the

distance between a department and each of the distance between a department and each of the other departmentsother departments

For each product, the path it will follow (routing) For each product, the path it will follow (routing) and its volume over some time periodand its volume over some time period


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Load-Distance AnalysisLoad-Distance AnalysisLoad-Distance AnalysisLoad-Distance Analysis

For each alternative process layout, compute the total For each alternative process layout, compute the total distance a product must travel using its routingdistance a product must travel using its routing

Compute the total distance traveled per time unit for Compute the total distance traveled per time unit for each product by multiplying its total travel distance each product by multiplying its total travel distance by its volume per time unitby its volume per time unit

Add the total distance traveled per time unit for each Add the total distance traveled per time unit for each productproduct

Select the layout with the smallest sumSelect the layout with the smallest sum

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Process Layout: Process Layout: Interdepartmental FlowInterdepartmental Flow

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

departmentsdepartments The cost of moving from one department to The cost of moving from one department to

anotheranother The existing or planned physical layout of the The existing or planned physical layout of the

plantplant DetermineDetermine

The “best” locations for each department, where The “best” locations for each department, where best means interdepartmental transportation, or best means interdepartmental transportation, or flow, costs flow, costs

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Process Layout: Process Layout: Cut-And-Try ApproachCut-And-Try Approach

Involves searching for departmental changes to Involves searching for departmental changes to reduce overall flow costreduce overall flow cost

Difficult to determine correct movesDifficult to determine correct moves

Non-optimal and based on limited criteria (cost, flow Non-optimal and based on limited criteria (cost, flow and distance) and distance)

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Process Layout: Process Layout: Systematic Layout PlanningSystematic Layout Planning

Numerical flow of items between departments Numerical flow of items between departments Can be impractical to obtainCan be impractical to obtain Does not account for the qualitative factors that Does not account for the qualitative factors that

may be crucial to the placement decisionmay be crucial to the placement decision Systematic Layout PlanningSystematic Layout Planning

Accounts for the importance of having each Accounts for the importance of having each department located next to every other departmentdepartment located next to every other department

Is also guided by trial and errorIs also guided by trial and error Switching departments then checking the results Switching departments then checking the results

of the “closeness” score of the “closeness” score

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Example 1: Systematic Layout PlanningExample 1: Systematic Layout PlanningReasons for ClosenessReasons for Closeness

Code

1

2

3

4

5

6

Reason

Type of customer

Ease of supervision

Common personnel

Contact necessary

Share same price

Psychology

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Example 1: Systematic Layout PlanningExample 1: Systematic Layout PlanningImportance of ClosenessImportance of Closeness

Value

A

E

I

O

U

X

ClosenessLinecode

Numericalweights

Absolutely necessary

Especially important

Important

Ordinary closeness OK

Unimportant

Undesirable

16

8

4

2

0

80

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Example 1: Systematic Layout PlanningExample 1: Systematic Layout PlanningRelating Reasons and ImportanceRelating Reasons and Importance

From

1. Credit department

2. Toy department

3. Wine department

4. Camera department

5. Candy department

6

I

--

U

4

A

--

U

--

U

1

I

1,6

A

--

U

1

X

1

X

To2 3 4 5

Area(sq. ft.)

100

400

300

100

100

Letter

Number

Closeness rating

Reason for rating

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Example 1: Systematic Layout PlanningExample 1: Systematic Layout PlanningThe Starting SolutionThe Starting Solution

1

2

4

3

5

U U

E

A

I

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Example 1: Systematic Layout PlanningExample 1: Systematic Layout PlanningInitial and Final LayoutsInitial and Final Layouts

1

2 4

3

5

Initial Layout

Ignoring space andbuilding constraints

2

5 1 43

50 ft

20 ft

Final Layout

Adjusted by squarefootage and buildingsize

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Designing and Analyzing a Product LayoutDesigning and Analyzing a Product Layout

Line BalancingLine Balancing

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Designing and Analyzing a Product LayoutDesigning and Analyzing a Product LayoutDesigning and Analyzing a Product LayoutDesigning and Analyzing a Product Layout

CharacteristicsCharacteristics InputsInputs Design ProcedureDesign Procedure How Good Is The Layout?How Good Is The Layout?

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Product Layout-Advantages/DisadvantagesProduct Layout-Advantages/Disadvantages

Advantages:Advantages: Low cost variable cost per Low cost variable cost per

unitunit Lower material handling Lower material handling

costscosts reduction in work in-process reduction in work in-process

inventoriesinventories easier training and easier training and

supervisionsupervision

Disadvantages:Disadvantages: High volume required High volume required

because of large initial because of large initial investmentinvestment

Work stoppage at any point Work stoppage at any point ties up the whole processties up the whole process

Lack of flexibility in Lack of flexibility in handling variety of products handling variety of products or production ratesor production rates

Advantages:Advantages: Low cost variable cost per Low cost variable cost per

unitunit Lower material handling Lower material handling

costscosts reduction in work in-process reduction in work in-process

inventoriesinventories easier training and easier training and

supervisionsupervision

Disadvantages:Disadvantages: High volume required High volume required

because of large initial because of large initial investmentinvestment

Work stoppage at any point Work stoppage at any point ties up the whole processties up the whole process

Lack of flexibility in Lack of flexibility in handling variety of products handling variety of products or production ratesor production rates

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Line Balancing ProblemLine Balancing ProblemLine Balancing ProblemLine Balancing Problem

Work stations are arranged so that the output of one is Work stations are arranged so that the output of one is an input to the next, i.e., a series connectionan input to the next, i.e., a series connection

Layout design involves assigning one or more of the Layout design involves assigning one or more of the tasks required to make a product to work stationstasks required to make a product to work stations


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The objective is to assign tasks to minimize the The objective is to assign tasks to minimize the workers’ idle time, therefore idle time costs, and meet workers’ idle time, therefore idle time costs, and meet the required production rate for the linethe required production rate for the line

In a perfectly balanced line, all workers would In a perfectly balanced line, all workers would complete their assigned tasks at the same time complete their assigned tasks at the same time (assuming they start their work simultaneously)(assuming they start their work simultaneously)

This would result in no idle timeThis would result in no idle time . . . more. . . more

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Unfortunately there are a number of conditions that Unfortunately there are a number of conditions that prevent the achievement of a perfectly balanced lineprevent the achievement of a perfectly balanced line The estimated times for tasksThe estimated times for tasks The precedence relationships for the tasksThe precedence relationships for the tasks The combinatorial nature of the problemThe combinatorial nature of the problem

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InputsInputsInputsInputs

The production rate required from the product layout The production rate required from the product layout or the cycle time.or the cycle time. The cycle time is the reciprocal of the production The cycle time is the reciprocal of the production

rate and visa versarate and visa versa All of the tasks required to make the productAll of the tasks required to make the product

It is assumed that these tasks can not be divided It is assumed that these tasks can not be divided furtherfurther


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InputsInputsInputsInputs

The estimated time to do each taskThe estimated time to do each task The precedence relationships between the tasksThe precedence relationships between the tasks

These relationships are determined by the technical These relationships are determined by the technical constraints imposed by the productconstraints imposed by the product

These relationships are displayed as a network These relationships are displayed as a network known as a precedence diagramknown as a precedence diagram

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Design ProcedureDesign ProcedureDesign ProcedureDesign Procedure

1.1. If not provided, find the cycle time for the line. If not provided, find the cycle time for the line. Remember the cycle time is the reciprocal of the Remember the cycle time is the reciprocal of the production rate. Make sure the cycle time is production rate. Make sure the cycle time is expressed in the same time units as the estimated task expressed in the same time units as the estimated task times.times.

2.2. Select the line-balancing heuristic that may be used to Select the line-balancing heuristic that may be used to help with the assignments. (Two heuristics are help with the assignments. (Two heuristics are described at the end of this procedure.)described at the end of this procedure.)


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3.3. Open a new work station with the full cycle time Open a new work station with the full cycle time remaining.remaining.

4.4. Determine which tasks are feasible, i.e., can be Determine which tasks are feasible, i.e., can be assigned to this work station at this time. For a task assigned to this work station at this time. For a task to be feasible, two conditions must be met:to be feasible, two conditions must be met: All tasks that precede that task must have already All tasks that precede that task must have already

been assignedbeen assigned The estimated task time must be less than or equal The estimated task time must be less than or equal

to the remaining cycle time for that work station.to the remaining cycle time for that work station.

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5.5. If there are no feasible tasks, assignments to that If there are no feasible tasks, assignments to that work station are complete. Go back to step 3 (or stop, work station are complete. Go back to step 3 (or stop, if all tasks have been assigned). if all tasks have been assigned).

If there is only one feasible task, assign it to the If there is only one feasible task, assign it to the work station. If there is more than one feasible task, work station. If there is more than one feasible task, use the heuristic (step 2) to determine which task to use the heuristic (step 2) to determine which task to assign. Reduce the work station’s remaining cycle assign. Reduce the work station’s remaining cycle time by the selected task’s time and return to step 4.time by the selected task’s time and return to step 4.

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Line-Balancing HeuristicsLine-Balancing HeuristicsLine-Balancing HeuristicsLine-Balancing Heuristics

Heuristic methodsHeuristic methods, based on simple rules, have been , based on simple rules, have been used to develop very good, not optimal, solutions to used to develop very good, not optimal, solutions to line balancing problems.line balancing problems.

Incremental Utilization HeuristicIncremental Utilization Heuristic - adds tasks to a - adds tasks to a workstation one at a time in the order of task workstation one at a time in the order of task precedence until utilization is 100% or is observed to precedence until utilization is 100% or is observed to fall. fall.

Longest-Task-Time HeuristicLongest-Task-Time Heuristic - adds tasks to a - adds tasks to a workstation one at a time in the order of task workstation one at a time in the order of task precedence, choosing - when a choice must be made - precedence, choosing - when a choice must be made - the task with the longest time.the task with the longest time.

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How Good Is the Design?How Good Is the Design?How Good Is the Design?How Good Is the Design?

Utilization is one way of objectively determining how Utilization is one way of objectively determining how near perfectly balanced an assignment scheme is.near perfectly balanced an assignment scheme is.

UtilizationUtilization is the percentage of time that a production is the percentage of time that a production line is working.line is working.

Utilization is calculated as:Utilization is calculated as:

or or

100 stations) work ofnumber (Actual Time) (Cycle

s task timeall of Sumx

x

100ons workstatiofnumber Actual

ons workstatiofnumber Minimumx

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Product Layouts-Major AssumptionsProduct Layouts-Major Assumptions

Volume is adequate for high equipment utilization.Volume is adequate for high equipment utilization. Product demand is stable enough to justify high Product demand is stable enough to justify high

investment in specialized equipment.investment in specialized equipment. Product is standardized or approaching a phase of Product is standardized or approaching a phase of

its life cycle that justifies investment in specialized its life cycle that justifies investment in specialized equipment.equipment.

Supplies of raw material and components are Supplies of raw material and components are adequate and of uniform quality to ensure they will adequate and of uniform quality to ensure they will work with the specialized equipment.work with the specialized equipment.

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Station 1

Min/Unit 6

Station 2

7

Station 3

3

Why is Balancing the Line Important?Why is Balancing the Line Important?

What’s Going to Happen?

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Example 1: The ALB ProblemExample 1: The ALB Problem

You’ve just been assigned the job a setting up an You’ve just been assigned the job a setting up an electric fan assembly line with the following tasks:electric fan assembly line with the following tasks:

Task Time (Mins) Description PredecessorsA 2 Assemble frame NoneB 1 Mount switch AC 3.25 Assemble motor housing NoneD 1.2 Mount motor housing in frame A, CE 0.5 Attach blade DF 1 Assemble and attach safety grill EG 1 Attach cord BH 1.4 Test F, G

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Example 1: The ALB Problem Example 1: The ALB Problem The Precedence DiagramThe Precedence Diagram

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

Which process step defines the maximum rate of Which process step defines the maximum rate of production?production?

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Example 1: The ALB ProblemExample 1: The ALB Problem We want to assemble 100 fans per dayWe want to assemble 100 fans per day

Required Cycle Time, C = Production time per period

Required output per period

C = 420 mins / day

100 units / day= 4.2 mins / unit

What do these numbers this represent?What do these numbers this represent?

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Example 1: The ALB ProblemExample 1: The ALB Problem We want to assemble 100 fans per dayWe want to assemble 100 fans per day

Theoretical Min. Number of Workstations, N

N = Sum of task times (T)

Cycle time (C)

t

t

N = 11.35 mins / unit

4.2 mins / unit= 2.702, or 3t

Why should we always round up?Why should we always round up?

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Example 1: The ALB ProblemExample 1: The ALB ProblemSelected Task Selection RulesSelected Task Selection Rules

Primary: Primary: Assign tasks in order the the largest number Assign tasks in order the the largest number of following tasks.of following tasks.

Secondary (tie-breaking): Secondary (tie-breaking): Assign tasks in order of the Assign tasks in order of the longest operating time longest operating time

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Example 1: The ALB ProblemExample 1: The ALB ProblemSelected Task Selection RulesSelected Task Selection Rules

Precedence Diagram

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

Station 1 Station 2 Station 3

Task Followers Time (Min)A 6 2C 4 3.25D 3 1.2B 2 1E 2 0.5F 1 1G 1 1H 0 1.4

Slide 67 of 96

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1



A (4.2-2=2.2)

Slide 68 of 96

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1



A (4.2-2=2.2)B (2.2-1=1.2)

Slide 69 of 96

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1



A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2

Slide 70 of 96

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1



A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2

C (4.2-3.25)=.95

Idle = .95

Slide 71 of 96

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1



A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2

C (4.2-3.25)=.95

Idle = .95

D (4.2-1.2)=3

Slide 72 of 96

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1



A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2

C (4.2-3.25)=.95

Idle = .95

D (4.2-1.2)=3E (3-.5)=2.5

Slide 73 of 96

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1



A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

Idle= .2

C (4.2-3.25)=.95

Idle = .95

D (4.2-1.2)=3E (3-.5)=2.5F (2.5-1)=1.5

Slide 74 of 96

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1



A (4.2-2=2.2)B (2.2-1=1.2)G (1.2-1= .2)

C (4.2-3.25)=.95 D (4.2-1.2)=3E (3-.5)=2.5F (2.5-1)=1.5H (1.5-1.4)=.1

Idle=.2 Idle=.95 Idle=.1

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Example 1: The ALB ProblemExample 1: The ALB Problem

• Which station is the bottleneck?

• What is the effective cycle time?

Efficiency =Sum of task times (T)

Actual number of workstations (Na) x Cycle time (C)

Efficiency =11.35 mins / unit

(3)(4.2mins / unit)=.901

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Designing and Analyzing a Cellular LayoutDesigning and Analyzing a Cellular Layout

Fundamental questions:Fundamental questions: Which parts are going to be produced in a cell?Which parts are going to be produced in a cell? Which processes are going to be assigned to a cell?Which processes are going to be assigned to a cell?

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Group TechnologyGroup TechnologyBenefitsBenefits

1. Better human relations1. Better human relations

2. Improved operator expertise2. Improved operator expertise

3. Less in-process inventory and material handling3. Less in-process inventory and material handling

4. Faster production setup4. Faster production setup

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Fundamental RequirementsFundamental Requirementsfor Parts to be Made in Cellsfor Parts to be Made in CellsFundamental RequirementsFundamental Requirementsfor Parts to be Made in Cellsfor Parts to be Made in Cells

Demand for the parts must be high enough and stable Demand for the parts must be high enough and stable enough that moderate batch sizes of the parts can be enough that moderate batch sizes of the parts can be produced periodically.produced periodically.

Parts must be capable of being grouped into parts Parts must be capable of being grouped into parts families.families.

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1.1. Form the Parts-Machines Matrix. Form the Parts-Machines Matrix.

2.2. Rearrange the Rows. Rearrange the Rows. Place the machines that produce the same parts in Place the machines that produce the same parts in

adjacent rows.adjacent rows.

3.3. Rearrange the Columns. Rearrange the Columns. Place the parts requiring the same machines in Place the parts requiring the same machines in

adjacent columns.adjacent columns.

4.4. Using the rearranged parts-machines matrix to Using the rearranged parts-machines matrix to identify cells, the machines for that cell and the parts identify cells, the machines for that cell and the parts that will be produced in that cell.that will be produced in that cell.

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Wrap-Up: World-Class PracticeWrap-Up: World-Class PracticeWrap-Up: World-Class PracticeWrap-Up: World-Class Practice

Strive for flexibility in layoutsStrive for flexibility in layouts Multi-job training of workersMulti-job training of workers Sophisticated preventive-maintenance programsSophisticated preventive-maintenance programs Flexible machinesFlexible machines Empowered workers trained in problem solvingEmpowered workers trained in problem solving Layouts small and compactLayouts small and compact

slide 0 of 96 chapter 8 facility layout: manufacturing and services manufacturing and services honey...

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