slide 0 of 96 chapter 8 facility layout: manufacturing and services manufacturing and services honey...
TRANSCRIPT
Slide 1 of 96
Chapter 8Chapter 8
Facility Layout:Facility Layout:
Manufacturing and ServicesManufacturing and Services
Honey Arora
MBA – III
Slide 2 of 96
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
Slide 3 of 96
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
Slide 4 of 96
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
Slide 5 of 96
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
Slide 6 of 96
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
Slide 7 of 96
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)
Slide 8 of 96
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
Slide 9 of 96
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 ..
Slide 10 of 96
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
Slide 11 of 96
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
Slide 12 of 96
Manufacturing Facility LayoutsManufacturing Facility Layouts
Slide 13 of 96
Basic Layout FormsBasic Layout FormsBasic Layout FormsBasic Layout Forms
ProcessProcess ProductProduct CellularCellular Fixed positionFixed position HybridHybrid
Slide 14 of 96
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)
Slide 15 of 96
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
Slide 16 of 96
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
Slide 17 of 96
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
Slide 18 of 96
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
Slide 19 of 96
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
Slide 20 of 96
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
Slide 21 of 96
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
Slide 22 of 96
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
Slide 23 of 96
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
Slide 24 of 96
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.
Slide 25 of 96
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
Slide 26 of 96
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
Slide 27 of 96
Process LayoutsProcess Layouts Product LayoutsProduct Layouts Cellular LayoutsCellular Layouts
Analyzing Manufacturing Facility LayoutsAnalyzing Manufacturing Facility LayoutsAnalyzing Manufacturing Facility LayoutsAnalyzing Manufacturing Facility Layouts
Slide 28 of 96
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?
Slide 29 of 96
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
Slide 30 of 96
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
Slide 31 of 96
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
Slide 32 of 96
Operations Sequence AnalysisOperations Sequence AnalysisOperations Sequence AnalysisOperations Sequence Analysis
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.
. . . more. . . more
Slide 33 of 96
Operations Sequence AnalysisOperations Sequence AnalysisOperations Sequence AnalysisOperations Sequence Analysis
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
Slide 34 of 96
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
Slide 35 of 96
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
. . . more. . . more
Slide 36 of 96
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
Slide 37 of 96
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
Slide 38 of 96
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)
Slide 39 of 96
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
Slide 40 of 96
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
Slide 41 of 96
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
Slide 42 of 96
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
Slide 43 of 96
Example 1: Systematic Layout PlanningExample 1: Systematic Layout PlanningThe Starting SolutionThe Starting Solution
1
2
4
3
5
U U
E
A
I
Slide 44 of 96
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
Slide 45 of 96
Designing and Analyzing a Product LayoutDesigning and Analyzing a Product Layout
Line BalancingLine Balancing
Slide 46 of 96
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?
Slide 47 of 96
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
Slide 48 of 96
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
. . . more. . . more
Slide 49 of 96
Line Balancing ProblemLine Balancing ProblemLine Balancing ProblemLine Balancing Problem
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
Slide 50 of 96
Line Balancing ProblemLine Balancing ProblemLine Balancing ProblemLine Balancing Problem
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
Slide 51 of 96
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
. . . more. . . more
Slide 52 of 96
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
Slide 53 of 96
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.)
. . . more. . . more
Slide 54 of 96
Design ProcedureDesign ProcedureDesign ProcedureDesign Procedure
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.
Slide 55 of 96
Design ProcedureDesign ProcedureDesign ProcedureDesign Procedure
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.
Slide 56 of 96
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.
Slide 57 of 96
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
Slide 58 of 96
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.
Slide 59 of 96
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?
Slide 60 of 96
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
Slide 61 of 96
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?
Slide 63 of 96
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?
Slide 64 of 96
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?
Slide 65 of 96
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
Slide 66 of 96
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Slide 75 of 96
Slide 76 of 96
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
Slide 77 of 96
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?
Slide 78 of 96
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
Slide 79 of 96
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.
Slide 80 of 96
Design ProcedureDesign ProcedureDesign ProcedureDesign Procedure
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.
Slide 81 of 96
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