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    Production Planning Solution

    Techniques Part 1 MRP, MRP-IIMads Kehlet Jepsen

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.1/3

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    Overview

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.2/3

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    Overview

    Material Requirement Planning(MRP)

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.2/3

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    Overview

    Material Requirement Planning(MRP)

    MRP Procedure

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.2/3

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    Overview

    Material Requirement Planning(MRP)

    MRP Procedure

    Issues with MRP

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.2/3

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    Overview

    Material Requirement Planning(MRP)

    MRP Procedure

    Issues with MRPManufacturing Resource Planning MRP II

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.2/3

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    Overview

    Material Requirement Planning(MRP)

    MRP Procedure

    Issues with MRPManufacturing Resource Planning MRP II

    Time driven Rough-Cut Capacity Planning

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.2/3

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    Overview

    Material Requirement Planning(MRP)

    MRP Procedure

    Issues with MRPManufacturing Resource Planning MRP II

    Time driven Rough-Cut Capacity Planning

    Heuristic for Time driven Rough-Cut Capacity Planning

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.2/3

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    Overview

    Material Requirement Planning(MRP)

    MRP Procedure

    Issues with MRPManufacturing Resource Planning MRP II

    Time driven Rough-Cut Capacity Planning

    Heuristic for Time driven Rough-Cut Capacity Planning

    Neighborhood for Time driven Rough-Cut CapacityPlanning

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.2/3

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    Material Requirement Planning(MRP)

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.3/3

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    Material Requirement Planning(MRP)

    Originally system was based on reorder point.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.3/3

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    Material Requirement Planning(MRP)

    Originally system was based on reorder point.

    Reorder point is suited for independent demand.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.3/3

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    Material Requirement Planning(MRP)

    Originally system was based on reorder point.

    Reorder point is suited for independent demand.

    But not for dependent demand.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.3/3

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    Material Requirement Planning(MRP)

    Originally system was based on reorder point.

    Reorder point is suited for independent demand.

    But not for dependent demand.MRP works backwards from independent demand toderive a schedule.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.3/3

    M i l R i Pl i (MRP)

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    Material Requirement Planning(MRP)

    Originally system was based on reorder point.

    Reorder point is suited for independent demand.

    But not for dependent demand.MRP works backwards from independent demand toderive a schedule.

    MRP is called a push system since it pushes items inthe production chain.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.3/3

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    Overview of MRP

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.4/3

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    Overview of MRP

    External orders is called Purchase orders.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.4/3

    O i f MRP

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    Overview of MRP

    External orders is called Purchase orders.

    Internal orders is called Jobs.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.4/3

    O i f MRP

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    Overview of MRP

    External orders is called Purchase orders.

    Internal orders is called Jobs.

    Time is divided into buckets.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.4/3

    O i f MRP

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    Overview of MRP

    External orders is called Purchase orders.

    Internal orders is called Jobs.

    Time is divided into buckets.The bill of material(BOM) describes relationship

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.4/3

    O i f MRP

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    Overview of MRP

    External orders is called Purchase orders.

    Internal orders is called Jobs.

    Time is divided into buckets.The bill of material(BOM) describes relationship

    The routing describes the work processes.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.4/3

    S h ti f MRP

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    Schematic of MRP

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.5/3

    MRP Inputs and Outputs

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    MRP Inputs and Outputs

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.6/3

    MRP Inputs and Outputs

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    MRP Inputs and Outputs

    Master Production Schedule:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.6/3

    MRP Inputs and Outputs

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    MRP Inputs and Outputs

    Master Production Schedule: Item, Quantity and duedates.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.6/3

    MRP Inputs and Outputs

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    MRP Inputs and Outputs

    Master Production Schedule: Item, Quantity and duedates.

    Erp Database:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.6/3

    MRP Inputs and Outputs

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    MRP Inputs and Outputs

    Master Production Schedule: Item, Quantity and duedates.

    Erp Database: BOM, Routing, lot-sizing rule(LSR),

    lead time(PLT) and On-Hand Inventory.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.6/3

    MRP Inputs and Outputs

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    MRP Inputs and Outputs

    Master Production Schedule: Item, Quantity and duedates.

    Erp Database: BOM, Routing, lot-sizing rule(LSR),

    lead time(PLT) and On-Hand Inventory.

    Scheduled Receipts: Out standing orders and Jobs.Work in process.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.6/3

    MRP Inputs and Outputs

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    MRP Inputs and Outputs

    Master Production Schedule: Item, Quantity and duedates.

    Erp Database: BOM, Routing, lot-sizing rule(LSR),

    lead time(PLT) and On-Hand Inventory.

    Scheduled Receipts: Out standing orders and Jobs.Work in process.

    MRP outputs: Planned order release, Change noticesand Exception reports.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.6/3

    MRP Procedure

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    MRP Procedure

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.7/3

    MRP Procedure

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    MRP Procedure

    Tis the number of time periods.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.7/3

    MRP Procedure

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    MRP Procedure

    Tis the number of time periods.

    Dt gross requirements (demand) for periodt

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.7/3

    MRP Procedure

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    MRP Procedure

    Tis the number of time periods.

    Dt gross requirements (demand) for periodt

    Stquantity currently scheduled to complete in period

    t

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.7/3

    MRP Procedure

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    MRP Procedure

    Tis the number of time periods.

    Dt gross requirements (demand) for periodt

    Stquantity currently scheduled to complete in period t

    It Projected on-hand inventory in period t

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.7/3

    MRP Procedure

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    MRP Procedure

    Tis the number of time periods.

    Dt gross requirements (demand) for periodt

    Stquantity currently scheduled to complete in period t

    It Projected on-hand inventory in period t

    Nt net requirements for periodt

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.7/3

    MRP Procedure: Netting

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    g

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.8/3

    MRP Procedure: Netting

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    g

    1. ComputeIt=It1 Dt t

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.8/3

    MRP Procedure: Netting

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    g

    1. ComputeIt=It1 Dt t

    2. Findtm={min1tT :It

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    g

    1. ComputeIt=It1 Dt t

    2. Findtm={min1tT :It tm

    . Generate Change Notice andadjust SR andSt.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.8/3

    MRP Procedure: Netting

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    g

    1. ComputeIt=It1 Dt t

    2. Findtm={min1tT :It tm

    . Generate Change Notice andadjust SR andSt. Continue untilIm>0or no moreSRs.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.8/3

    MRP Procedure: Netting

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    1. ComputeIt=It1 Dt t

    2. Findtm={min1tT :It tm

    . Generate Change Notice andadjust SR andSt. Continue untilIm>0or no moreSRs.

    4. Adjust projected on-hand inventory toIt=It+ St

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.8/3

    MRP Procedure: Netting

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    1. ComputeIt=It1 Dt t

    2. Findtm={min1tT :It tm

    . Generate Change Notice andadjust SR andSt. Continue untilIm>0or no moreSRs.

    4. Adjust projected on-hand inventory toIt=It+ St

    5. Findt ={t|It

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    Netting example

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    Gross requierments 15 20 50 50

    Scheduled receipts 10 10

    Adjusted SRs

    Projected on-hand 20

    Net requirements

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.9/3

    Netting example

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    Gross requierments 15 20 50 50

    Scheduled receipts 10 10

    Adjusted SRs

    Projected on-hand 20 5

    Net requirements

    I1=D1 I0= 5

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.9/3

    Netting example

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    Gross requierments 15 20 50 50

    Scheduled receipts 10 10

    Adjusted SRs 20

    Projected on-hand 20 5

    Net requirements

    I1=D1 I0= 5I1>0AdjustS1. S2=S2+ S1 = 20

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.9/3

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    Netting example

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    Gross requierments 15 20 50 50

    Scheduled receipts 10 10

    Adjusted SRs 20

    Projected on-hand 20 5 5 -45 -

    Net requirements 45

    I1=D1 I0= 5I1>0AdjustS1. S2=S2+ S1 = 20

    I2=I1 D2= 5 20

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    Gross requierments 15 20 50 50

    Scheduled receipts 10 10

    Adjusted SRs 20

    Projected on-hand 20 5 5 -45 -

    Net requirements 45 50

    I1=D1 I0= 5I1>0AdjustS1. S2=S2+ S1 = 20

    I2=I1 D2= 5 20

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    MRP Procedure continued

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    Lot sizing:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    MRP Procedure continued

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    Lot sizing:Wagner Whitin

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    MRP Procedure continued

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    Lot sizing:Wagner Whitin

    lot for lot

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    MRP Procedure continued

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    Lot sizing:Wagner Whitin

    lot for lot

    fixed order period

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    MRP Procedure continued

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    Lot sizing:Wagner Whitin

    lot for lot

    fixed order periodFixed order Quantity and EOQ.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    MRP Procedure continued

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    Lot sizing:Wagner Whitin

    lot for lot

    fixed order periodFixed order Quantity and EOQ.

    Part-Period Balancing. Balancing inventory cost and

    Setup Cost.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    MRP Procedure continued

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    Lot sizing:Wagner Whitin

    lot for lot

    fixed order periodFixed order Quantity and EOQ.

    Part-Period Balancing. Balancing inventory cost and

    Setup Cost.Time fasing. All lead times are considered for items, notfor status on floor

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    MRP Procedure continued

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    Lot sizing:Wagner Whitin

    lot for lot

    fixed order periodFixed order Quantity and EOQ.

    Part-Period Balancing. Balancing inventory cost and

    Setup Cost.Time fasing. All lead times are considered for items, notfor status on floor

    Bom Explosion. Netting and lot sizing is done for eachsub item.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.10/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10

    Quantity 1 setup cost Part-Periods Inventory cost

    10 30 0 0

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10

    Quantity 1 setup cost Part-Periods Inventory cost

    10 30 0 0

    25

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

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    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10Quantity 1 setup cost Part-Periods Inventory cost

    10 30 0 0

    25 30 15

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10Quantity 1 setup cost Part-Periods Inventory cost

    10 30 0 0

    25 30 15 15

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10Quantity 1 setup cost Part-Periods Inventory cost

    10 30 0 0

    25 30 15 15

    35

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10Quantity 1 setup cost Part-Periods Inventory cost

    10 30 0 0

    25 30 15 15

    35 30

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10Quantity 1 setup cost Part-Periods Inventory cost

    10 30 0 0

    25 30 15 15

    35 30 35

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Part Period Balancing

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    Number of itemsnNumber of Periodspthe item is carried in the inventory.

    Part Period cost isn p

    Example:

    Period 1 2 3

    Net Requirements 10 15 10Quantity 1 setup cost Part-Periods Inventory cost

    10 30 0 0

    25 30 15 15

    35 30 35 35

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.11/3

    Issues with MRP

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.12/3

    Issues with MRP

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    Assume constant lead times. To take care of variationSafety Stock and Safety Lead time is used.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.12/3

    Issues with MRP

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    Assume constant lead times. To take care of variationSafety Stock and Safety Lead time is used.

    Capacity Infeasibility, there is no capacity check.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.12/3

    Issues with MRP

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    Assume constant lead times. To take care of variationSafety Stock and Safety Lead time is used.

    Capacity Infeasibility, there is no capacity check.

    Long Planned Lead time due to variation in deliverytime.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.12/3

    Issues with MRP

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    Assume constant lead times. To take care of variationSafety Stock and Safety Lead time is used.

    Capacity Infeasibility, there is no capacity check.

    Long Planned Lead time due to variation in deliverytime.

    System Nervousness. Plans that are feasible can

    become infeasible.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.12/3

    Questians or comments to MRP

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    Are there any questians or comments ?

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.13/3

    Manufacturing Resource Planning

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.14/3

    Manufacturing Resource Planning

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    Address deficiencies in MRP

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.14/3

    Manufacturing Resource Planning

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    Address deficiencies in MRPBrings in new functionalities including:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.14/3

    Manufacturing Resource Planning

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    Address deficiencies in MRPBrings in new functionalities including:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.14/3

    Long-Range Planning

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.15/3

    Long-Range Planning

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    Forecasting seeks to predict demands of the future.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.15/3

    Long-Range Planning

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    Forecasting seeks to predict demands of the future.Resource Planning. Determines long time capacityneed. Is used to decide is knew facilities must be build

    or old facilities must be expanded.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.15/3

    Long-Range Planning

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    Forecasting seeks to predict demands of the future.Resource Planning. Determines long time capacityneed. Is used to decide is knew facilities must be build

    or old facilities must be expanded.Aggregate Planning. Determines how inventory is build.Do we use overtime or do we carry inventory over a

    long period.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.15/3

    Intermidiate Planning

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.16/3

    Intermidiate Planning

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    Demand management Converts long-term forecast intoactual customer orders and forecast of anticipatedorders.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.16/3

    Intermidiate Planning

    D d C l f i

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    Demand management Converts long-term forecast intoactual customer orders and forecast of anticipatedorders.

    Available to promise Secures that an order can be meetat a given due date. This can be done by using forwardloading.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.16/3

    Intermidiate Planning

    D d t C t l t f t i t

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    Demand management Converts long-term forecast intoactual customer orders and forecast of anticipatedorders.

    Available to promise Secures that an order can be meetat a given due date. This can be done by using forwardloading.

    Master Production Schedule Generates an anticipatedproduction schedule.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.16/3

    Intermidiate Planning

    D d t C t l t f t i t

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    Demand management Converts long-term forecast intoactual customer orders and forecast of anticipatedorders.

    Available to promise Secures that an order can be meetat a given due date. This can be done by using forwardloading.

    Master Production Schedule Generates an anticipatedproduction schedule.

    Rough-cut Planning Provides a schedule where thecapacity on critical resources is meet.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.16/3

    Intermidiate Planning

    D d t C t l t f t i t

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    Demand management Converts long-term forecast intoactual customer orders and forecast of anticipatedorders.

    Available to promise Secures that an order can be meetat a given due date. This can be done by using forwardloading.

    Master Production Schedule Generates an anticipatedproduction schedule.

    Rough-cut Planning Provides a schedule where thecapacity on critical resources is meet.

    Capacity Requirements Planning Does not preformactual capacity check. CRP assumes infinite capacityon resources. Basically it just calculates finish dates

    based on fixed lead times.Production Planning Solution Techniques Part 1 MRP, MRP-II p.16/3

    Short-term control

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.17/3

    Short-term control

    Job release Converts jobs to scheduled receipts

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    Job release Converts jobs to scheduled receipts.Resolves conflicts if several high-level items uses samelow-level item.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.17/3

    Short-term control

    Job release Converts jobs to scheduled receipts

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    Job release Converts jobs to scheduled receipts.Resolves conflicts if several high-level items uses samelow-level item.

    Job dispatching Maintains queue in front of eachworkstation and try to maintain due date.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.17/3

    Short-term control

    Job release Converts jobs to scheduled receipts

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    Job release Converts jobs to scheduled receipts.Resolves conflicts if several high-level items uses samelow-level item.

    Job dispatching Maintains queue in front of eachworkstation and try to maintain due date.

    Shortest process time Chooses the shortest job

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.17/3

    Short-term control

    Job release Converts jobs to scheduled receiptsfl f

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    Job release Converts jobs to scheduled receipts.Resolves conflicts if several high-level items uses samelow-level item.

    Job dispatching Maintains queue in front of eachworkstation and try to maintain due date.

    Shortest process time Chooses the shortest job

    Earliest due date dispatches job with nearest duedate

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.17/3

    Short-term control

    Job release Converts jobs to scheduled receiptsR l fli if l hi h l l i

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    Job release Converts jobs to scheduled receipts.Resolves conflicts if several high-level items uses samelow-level item.

    Job dispatching Maintains queue in front of eachworkstation and try to maintain due date.

    Shortest process time Chooses the shortest job

    Earliest due date dispatches job with nearest duedate

    Least slack Choose job where, the due date minusremaining process time is lowest.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.17/3

    Short-term control

    Job release Converts jobs to scheduled receiptsR l fli t if l hi h l l it

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    Job release Converts jobs to scheduled receipts.Resolves conflicts if several high-level items uses samelow-level item.

    Job dispatching Maintains queue in front of eachworkstation and try to maintain due date.

    Shortest process time Chooses the shortest job

    Earliest due date dispatches job with nearest duedate

    Least slack Choose job where, the due date minusremaining process time is lowest.

    Least slack per remaining operation Divide slackwith number of operation remaining on routing.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.17/3

    Questians or comments to MRP II

    Are there any questians or comments ?

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    Are there any questians or comments ?

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.18/3

    Rough-Cut Capacity Planning(RCCP)

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.19/3

    Rough-Cut Capacity Planning(RCCP)

    Considers aggregated work

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    Considers aggregated work

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.19/3

    Rough-Cut Capacity Planning(RCCP)

    Considers aggregated work

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    Considers aggregated workAllocates work in time buckets

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.19/3

    Rough-Cut Capacity Planning(RCCP)

    Considers aggregated work

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    Co s de s agg egated oAllocates work in time buckets

    Determines resources in order to reach due dates

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.19/3

    Rough-Cut Capacity Planning(RCCP)

    Considers aggregated workAll k i i b k

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    gg gAllocates work in time buckets

    Determines resources in order to reach due dates

    Both regular and nonregular (outsourcing over timeetc.) is considered

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.19/3

    Rough-Cut Capacity Planning(RCCP)

    Considers aggregated workAll t k i ti b k t

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    gg gAllocates work in time buckets

    Determines resources in order to reach due dates

    Both regular and nonregular (outsourcing over timeetc.) is considered

    Time driven RCCP is when project dates must be meet.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.19/3

    Rough-Cut Capacity Planning(RCCP)

    Considers aggregated workAll t k i ti b k t

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    gg gAllocates work in time buckets

    Determines resources in order to reach due dates

    Both regular and nonregular (outsourcing over timeetc.) is considered

    Time driven RCCP is when project dates must be meet.

    In resource-driven RCCP only regular capacity can beused

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.19/3

    Rough-Cut Capacity Planning(RCCP)

    Considers aggregated workAllocates work in time buckets

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    gg gAllocates work in time buckets

    Determines resources in order to reach due dates

    Both regular and nonregular (outsourcing over timeetc.) is considered

    Time driven RCCP is when project dates must be meet.

    In resource-driven RCCP only regular capacity can beused

    This session will consider the time driven

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.19/3

    Some notation

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobsJ1, J2, , Jn

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobsJ1, J2, , Jnk resources R1 R

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    kresourcesR1, , Rn

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobsJ1

    , J2

    , , Jnk resources R1 R

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    kresourcesR1, , Rn

    Ttime buckets

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobsJ1

    , J2

    , , Jnk resources R1 R

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    kresourcesR1, , Rn

    Ttime buckets

    Qkt is the regular capacity for resourcekin periodt

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobsJ1

    , J2

    , , Jnk resources R1 Rn

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    kresourcesR1, , Rn

    Ttime buckets

    Qkt is the regular capacity for resourcekin periodt

    JobJj requiresqjk units of resourcek

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobsJ1

    , J2

    , , Jnk resources R1, , Rn

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    kresourcesR1, , Rn

    Ttime buckets

    Qkt is the regular capacity for resourcekin periodt

    JobJj requiresqjk units of resourcek

    xkt

    denotes the fraction of jobJj

    performed in periodt

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobsJ1

    , J2

    , , Jnk resources R1, , Rn

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    kresourcesR1, , Rn

    Ttime buckets

    Qkt is the regular capacity for resourcekin periodt

    JobJj requiresqjk units of resourcek

    xkt

    denotes the fraction of jobJj

    performed in periodt

    Jj must be performed in time window[rj , dj ]

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobsJ1

    , J2

    , , JnkresourcesR1, , Rn

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    1, , n

    Ttime buckets

    Qkt is the regular capacity for resourcekin periodt

    JobJj requiresqjk units of resourcek

    xkt

    denotes the fraction of jobJj performed in periodt

    Jj must be performed in time window[rj , dj ]

    pj is the minimum number of periods jobJj can use.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Some notation

    njobs

    J1

    , J2

    , , JnkresourcesR1, , Rn

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    1, , n

    Ttime buckets

    Qkt is the regular capacity for resourcekin periodt

    JobJj requiresqjk units of resourcek

    xkt

    denotes the fraction of jobJj performed in periodt

    Jj must be performed in time window[rj , dj ]

    pj is the minimum number of periods jobJj can use.

    1pj

    is the maximum fraction of a job that can be

    completed in a week.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.20/3

    Precedence constraints

    If jobJimust finish beforeJj there is a precedence relation.For a periodthis can be modelled as:

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.21/3

    Precedence constraints

    If jobJi

    must finish beforeJj

    there is a precedence relation.For a periodthis can be modelled as:

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    xj >0

    1t=dt

    xit= 1

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.21/3

    Precedence constraints

    If jobJi

    must finish beforeJj

    there is a precedence relation.For a periodthis can be modelled as:

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    xj >0

    1t=dt

    xit= 1

    There will bedj rj constraints per precedence relation.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.21/3

    Precedence constraints

    If jobJimust finish beforeJ

    jthere is a precedence relation.

    For a periodthis can be modelled as:

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    xj >0

    1t=dt

    xit= 1

    There will bedj rj constraints per precedence relation.

    Time windows can in some cases be tightened, due to

    precedence constraints.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.21/3

    Nonregular capacity

    LetQkt

    denote the nonregular capacity for resourcekinperiodt. Then for each resource and time period:

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.22/3

    Nonregular capacity

    LetQkt

    denote the nonregular capacity for resourcekinperiodt. Then for each resource and time period:

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    Ukt = max{0,

    n

    j=1 qjkxjt Qkt

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.22/3

    Nonregular capacity

    LetQkt

    denote the nonregular capacity for resourcekinperiodt. Then for each resource and time period:

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    Ukt = max{0,

    n

    j=1 qjkxjt Qkt

    The cost of using nonregular capacity for resource kin time

    period t is ckt

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.22/3

    Nonregular capacity

    LetQkt

    denote the nonregular capacity for resourcekinperiodt. Then for each resource and time period:

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    Ukt = max{0,

    n

    j=1 qjkxjt Qkt

    The cost of using nonregular capacity for resource kin time

    period t is ckt It is assumed that there is no limit on the

    nonregular resources.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.22/3

    Mathematical Model

    min T

    t=1

    Kk=1 cktUkt

    bj t t

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    subject to

    djt=rj xjt = 1 1j nxjt

    1

    pj1j n, 1tT

    nj=1 qjkxjt Ukt 0 1j n, 1tT

    xjt, Ukt 0 1j n, 1tT

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.23/3

    Controlling feasibility

    Allowed To Work window for jobJj is defined as[Sj , Cj ].

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.24/3

    Controlling feasibility

    Allowed To Work window for jobJj is defined as[Sj , Cj ].

    JobJj cannot start beforeSj or afterCj

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.24/3

    Controlling feasibility

    Allowed To Work window for jobJj is defined as[Sj , Cj ].

    JobJj cannot start beforeSj or afterCj

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    A ATW for jobJj is feasible if:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.24/3

    Controlling feasibility

    Allowed To Work window for jobJj is defined as[Sj , Cj ].

    JobJj cannot start beforeSj or afterCj

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    A ATW for jobJj is feasible if:

    1. Sj rj andCj dj

    2. Cj Sj pj1

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.24/3

    Controlling feasibility

    Allowed To Work window for jobJj is defined as[Sj , Cj ].

    JobJj cannot start beforeSj or afterCj

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    A ATW for jobJj is feasible if:

    1. Sj rj andCj dj

    2. Cj Sj pj1

    A setSof ATW windows is feasible if:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.24/3

    Controlling feasibility

    Allowed To Work window for jobJj is defined as[Sj , Cj ].

    JobJj cannot start beforeSj or afterCj

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    A ATW for jobJj is feasible if:

    1. Sj rj andCj dj

    2. Cj Sj pj1

    A setSof ATW windows is feasible if:

    1. Every ATW window is feasible

    2. Sj > Cj ifJiJj

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.24/3

    Mathematical Model ATW windows

    sjt=

    1 Sj tCj0 otherwise

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    0 otherwise

    (PS)min T

    t=1

    Kk=1 cktUkt

    subjectto djt=rj xjt = 1 1j n

    xjt sjpj

    1j n, 1tT

    nj=1 qjkxjt Ukt 0 1j n, 1tTxjt, Ukt 0 1j n, 1tT

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.25/3

    Constructive heuristics(HBASIC)

    Construct a feasible setSof ATW windows.

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.26/3

    Constructive heuristics(HBASIC)

    Construct a feasible setSof ATW windows.

    Solve problemPS

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.26/3

    Constructive heuristics(HBASIC)

    Construct a feasible setSof ATW windows.

    Solve problemPS

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    To obtain a feasible set of ATW windows construct them as

    follows:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.26/3

    Constructive heuristics(HBASIC)

    Construct a feasible setSof ATW windows.

    Solve problemPS

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    To obtain a feasible set of ATW windows construct them as

    follows:SetSj =rj

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.26/3

    Constructive heuristics(HBASIC)

    Construct a feasible setSof ATW windows.

    Solve problemPS

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    To obtain a feasible set of ATW windows construct them as

    follows:SetSj =rj

    SetCj = min{dj , mink|jiJkrk1}

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.26/3

    Constructive heuristics(HBASIC)

    Construct a feasible setSof ATW windows.

    Solve problemPS

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    To obtain a feasible set of ATW windows construct them as

    follows:SetSj =rj

    SetCj = min{dj , mink|jiJkrk1}

    Have I forgotten an important assumption ?

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.26/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

    {Ji1, Ji2, , Jik}is a ordered set if:

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

    {Ji1, Ji2, , Jik}is a ordered set if:

    Ji Ji Ji Ji Ji Ji

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    Ji1 Ji2, Ji3 Ji4, , Jik1 Jik

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

    {Ji1, Ji2, , Jik}is a ordered set if:

    Ji1 Ji2, Ji3 Ji4, , Jik 1 Jik

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    Ji1 Ji2, Ji3 Ji4, , Jik1 Jik

    A critical path is a path where:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

    {Ji1, Ji2, , Jik}is a ordered set if:

    Ji1 Ji2, Ji3 Ji4, , Jik 1 Jik

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    Ji1 Ji2, Ji3 Ji4, , Jik1 Jik

    A critical path is a path where:

    Lj1 =Lj2== min1n Lj

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

    {Ji1, Ji2, , Jik}is a ordered set if:

    Ji1 Ji2, Ji3 Ji4, , Jik 1 Jik

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    i1 i2, i3 i4, , ik1 ik

    A critical path is a path where:

    Lj1 =Lj2== min1n Lj

    Sji =Sji1+pi1 for2iR

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

    {Ji1, Ji2, , Jik}is a ordered set if:

    Ji1 Ji2, Ji3 Ji4, , Jik1 Jik

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    i1 i2, i3 i4, , ik1 ik

    A critical path is a path where:

    Lj1 =Lj2== min1n Lj

    Sji =Sji1+pi1 for2iRCji =Cji+1pji+1 for1iR

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

    {Ji1, Ji2, , Jik}is a ordered set if:

    Ji1 Ji2, Ji3 Ji4, , Jik1 Jik

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    1 2,

    3 4, ,

    k 1 k

    A critical path is a path where:

    Lj1 =Lj2== min1n Lj

    Sji =Sji1+pi1 for2iRCji =Cji+1pji+1 for1iR

    A critical path is maximal if for allJl:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    Constructive heuristics (HCP M)

    Define the slack of jobJj asLj =Cj(Sj+pj)

    {Ji1, Ji2, , Jik}is a ordered set if:

    Ji1 Ji2, Ji3 Ji4, , Jik1 Jik

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    1 2 3 4 k 1 k

    A critical path is a path where:

    Lj1 =Lj2== min1n Lj

    Sji =Sji1+pi1 for2iRCji =Cji+1pji+1 for1iR

    A critical path is maximal if for allJl:{Ji1, Ji2, , Jik , Jil}is critical

    {Jil, Ji1, Ji2 , , Jik}is critical

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.27/3

    (HCP M) continued

    InitializeSj =rj andCj =dj for allJj

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.28/3

    (HCP M) continued

    InitializeSj =rj andCj =dj for allJj

    Compute the slack for all jobs

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.28/3

    (HCP M) continued

    InitializeSj =rj andCj =dj for allJj

    Compute the slack for all jobs

    Find a maximal critical path{Ji1 , Ji2, , Jik}

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.28/3

    (HCP M) continued

    InitializeSj =rj andCj =dj for allJj

    Compute the slack for all jobs

    Find a maximal critical path{Ji1 , Ji2, , Jik}

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    Compute the total slack L=CjR(Sj1+

    Ri=1pji

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.28/3

    (HCP M) continued

    InitializeSj =rj andCj =dj for allJj

    Compute the slack for all jobs

    Find a maximal critical path{Ji1 , Ji2, , Jik}

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    Compute the total slack L=CjR(Sj1+

    Ri=1pji

    SetSji =Sj1+

    i1k=1pik+ |L

    i1k=1pik/

    Rk=1pik |

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.28/3

    (HCP M) continued

    InitializeSj =rj andCj =dj for allJj

    Compute the slack for all jobs

    Find a maximal critical path{Ji1 , Ji2, , Jik}

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    Compute the total slack L=CjR(Sj1+

    Ri=1pji

    SetSji =Sj1+

    i1k=1pik+ |L

    i1k=1pik/

    Rk=1pik |

    Change toCik =Sik+11

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.28/3

    HCP Mexample

    1 2 3 4

    S 0 5 15 20

    C 10 15 25 30

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    p 5 5 10 5

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.29/3

    HCP Mexample

    1 2 3 4

    S 0 5 15 20

    C 10 15 25 30

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    p 5 5 10 5L=C4(0 + 20) = 5

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.29/3

    HCP Mexample

    1 2 3 4

    S 0 5 15 20

    C 10 15 25 30

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    p 5 5 10 5L=C4(0 + 20) = 5

    Recall Sji =Sji+i1k=1pjk+ |Li1k=1 /Rk=1pjk|

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.29/3

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    HCP Mexample

    1 2 3 4

    S 0 5 15 20

    C 10 15 25 30

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    p 5 5 10 5L=C4(0 + 20) = 5

    Recall Sji =Sji+i1k=1pjk+ |Li1k=1 /Rk=1pjk|S2= 0 + 5 +

    5525

    = 6

    S3= 0 + 10 + 10525

    = 12

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.29/3

    HCP Mexample

    1 2 3 4

    S 0 5 15 20

    C 10 15 25 30

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    p 5 5 10 5L=C4(0 + 20) = 5

    Recall Sji =Sji+i1k=1pjk+ |Li1k=1 /Rk=1pjk|S2= 0 + 5 +

    5525

    = 6

    S3= 0 + 10 + 10525

    = 12

    S4= 0 + 20 + 20525

    = 24

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.29/3

    HCP Mexample

    1 2 3 4

    S 0 5 15 20

    C 10 15 25 30

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    p 5 5 10 5L=C4(0 + 20) = 5

    Recall Sji =Sji+i1k=1pjk+ |Li1k=1 /Rk=1pjk|S2= 0 + 5 +

    5525

    = 6

    S3= 0 + 10 + 10525

    = 12

    S4= 0 + 20 + 20525

    = 24

    C1=S21 = 5,C2= 11,C3= 23

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.29/3

    Neighbourhoods

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.30/3

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    Neighbourhoods

    For jobJj increaseSj or decreaseCj

    DecreaseSj impliesSj > rj,Ck =Sj1for anypreceding jobJk andCk Sk pk

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.30/3

    Neighbourhoods

    For jobJj increaseSj or decreaseCj

    DecreaseSj impliesSj > rj,Ck =Sj1for anypreceding jobJk andCk Sk pk

    Neighbourhood can be ordered after the greedy choice

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    e g bou ood ca be o de ed a te t e g eedy c o ceor the steepest edge rule.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.30/3

    Exercises

    Ex 1 Suggest some improvements for 2-3 of the

    modules in the MRP II model. You should describewhat additional data the system and need and whatvalue it would add for the users.

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    Production Planning Solution Techniques Part 1 MRP, MRP-II p.31/3

    Exercises

    Ex 1 Suggest some improvements for 2-3 of the

    modules in the MRP II model. You should describewhat additional data the system and need and whatvalue it would add for the users.

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    Ex 2 For RCCP we have focused on the time drivencase in this exercise we consider the resource drivencase:

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.31/3

    Exercises

    Ex 1 Suggest some improvements for 2-3 of the

    modules in the MRP II model. You should describewhat additional data the system and need and whatvalue it would add for the users.

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    Ex 2 For RCCP we have focused on the time drivencase in this exercise we consider the resource drivencase:

    Ex 2.1 Give a mathematical model for the Resourcedriven RCCP without precedence constraints.

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.31/3

    Exercises

    Ex 1 Suggest some improvements for 2-3 of the

    modules in the MRP II model. You should describewhat additional data the system and need and whatvalue it would add for the users.

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    Ex 2 For RCCP we have focused on the time drivencase in this exercise we consider the resource drivencase:

    Ex 2.1 Give a mathematical model for the Resourcedriven RCCP without precedence constraints.

    Ex 2.2 If we useHBASICto solve the resource drivenRCCP will it result in a feasible solution ? Justify you

    answer

    Production Planning Solution Techniques Part 1 MRP, MRP-II p.31/3

    Exercises

    Ex 1 Suggest some improvements for 2-3 of the

    modules in the MRP II model. You should describewhat additional data the system and need and whatvalue it would add for the users.

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    Ex 2 For RCCP we have focused on the time drivencase in this exercise we consider the resource drivencase:

    Ex 2.1 Give a mathematical model for the Resourcedriven RCCP without precedence constraints.

    Ex 2.2 If we useHBASICto solve the resource drivenRCCP will it result in a feasible solution ? Justify you

    answer

    Ex 2.3 Describe a heuristic for the resource drivenRCCP. The heuristic should include a constructive

    heuristic and a improvement heuristic.Production Planning Solution Techniques Part 1 MRP, MRP-II p.31/3


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