Upload
jairo
View
65
Download
2
Tags:
Embed Size (px)
Citation preview
• A large variety of products:
• Example 1: IBM (desktops, laptops, mainframes, special-purpose computers, etc; furthermore, many models for each of the above categories)
• Example 2: Ford (sedans, SUV’s minivans, trucks, etc; again, many models and variations in each category)
• Product structure: An assembly of a number of components and subassemblies
• Example:
• (Desktop) Computer
• Motherboard
• CPU-card
• I/O card
• Modem card
• Power supply unit
• Ventilator
• etc.
• Monitor
• Keyboard
• Mouse
• (other peripherals)
• Some components and subassemblies are produced in-house, and some are procured from outside.
Bill of Materials (BOM)
Raw
Material
& Comp.
Inventory
Finished
Item
Inventory
S1,2S1,1 S1,n
S2,1 S2,2 S2,m
Assembly Line 1: Product Family 1
Assembly Line 2: Product Family 2
Backend Operations
Dept. 1 Dept. 2 Dept. k
S1,i
S2,i
Dept. j
Aggregate Planning
Master Production Scheduling
Materials Requirement Planning
Aggregate Unit
Demand
End Item (SKU)
Demand
Corporate Strategy
Capacity and Aggregate Production Plans
SKU-level Production Plans
Manufacturing
and Procurement
lead times
Component Production lots and due dates
Part process
plans
(Plan. Hor.: 1 year, Time Unit: 1 month)
(Plan. Hor.: a few months, Time Unit: 1 week)
(Plan. Hor.: a few months, Time Unit: 1 week)
Shop floor-level Production Control(Plan. Hor.: a day or a shift, Time Unit: real-time)
• Effective Data Collection and Maintenance/Data Integrity: There is a need for a monitoring tool that will provide a centralized, correct and efficient representation of the system status at any point in time.
• Industry Solution: Manufacturing Execution Systems (MES)
• e.g., SAP, Oracle, PeopleSoft
• Efficient and Coherent Computerized Planning Tools: There is a need for a suite of computationally efficient planning tools that will effectively address the problems arising at the various levels of the decomposition framework, while maintaining plan consistency across the different levels.
• Industry Solution: Product and Supply Chain Planning Software
• e.g., I2 Technologies, BAAN, Manugistics
•Items (or Stock Keeping Units - SKU’s): The final products delivered to the
(downstream) customers
•Families: Group of items that share a common manufacturing setup cost;
i.e., they have similar production requirements.
•Types: Groups of families with production quantities that are determined in a
single aggregate production plan.
•Aggregate Unit: A fictitious item representing an entire product type.
•Aggregate Unit Production Requirements: The amount of (labor) time
required for the production of one aggregate unit. This is computed by
appropriately averaging the labor time requirements over the entire set of
items represented by the aggregate unit.
•Aggregate Unit Demand: The cumulative demand for the entire set of items
represented by the aggregate unit.
Remark: Being the cumulate of a number of independent demand series, the
demand for the aggregate unit is a more robust estimate than its constituent
components.
Washing machine
Model Number
Required labor time
(hrs)
Item demand as % of
aggregate demand
A5532 4.2 32
K4242 4.9 21
L9898 5.1 17
3800 5.2 14
M2624 5.4 10
M3880 5.8 06
Aggregate unit labor time = (.32)(4.2)+(.21)(4.9)+(.17)(5.1)+(.14)(5.2)+
(.10)(5.4)+(.06)(5.8) = 4.856 hrs
Plan Agregado
Demanda en U.Q
Disponibilidad de
Unidades Equiva.
(Situación del
Invenario actual)
Plan Agregado de
producción
Capacidad
de Producción
Requerida
Requerimiento de laProducción en U.Q
Estrategia Corporativa
Plan Agregado de Producción:
•Niveles de la Producción Agregada
•Niveles del Inventario Agregado
•Niveles de los Pedidos pendiente Agregados
Plan de Capacidad de Producción:
•Nivel(es) Fuerza Laboral
•Nivel(es) Sobretiempo
•Cantidad de Subcontratados
1. Caza de la demanda: Variar el nivel de Fuerza Laboral
D(t) P(t) = D(t)
W(t)
PC WC HC FC
•D(t): Demanda Agregada
•P(t): Nivel de Producción Agregada
•W(t): Nivel de Fuerza de Trabajo Requerida
•Costos involucrados:
•PC: Costos de Producción
•Fijos(maquinaria, Gastos generales)
•Variable(materiales, consumibles, etc.)
•WC: Costo de trabajo regular
•HC: Costos de contratación: e.g., anuncios, entrevistas, capacitación
•FC: Costos de despidos: e.g., compensación, costo social
Estrategias de Planeamiento Agregado Puro
2. Variando la Capacidad para producir con empleados constantes.
D(t) P(t)
O(t)
PC WC OC UC
U(t)
S(t)
SC
W = ct•S(t): Cantidades subcontratadas (compradas a terceros)
•O(t): Número de horas extras.
•U(t): Undertime levels
•Costos involucrados:
•PC, WC: como lo anterior
•SC: Costo por subcontratar (tercerizar): e.g., purchasing, transport, quality, etc.
•OC: overtime costs: incremental cost of producing one unit in overtime
•(UC: undertime costs: this is hidden in WC)
Estrategias de Planeamiento Agregado Puro
3. Accumulating (Seasonal) Inventories:
D(t) P(t)
I(t)
PC WC IC
W(t), O(t), U(t), S(t) = ct
•I(t): Nivel de Inventario Acumulado
•Costos involucrados:
•PC, WC: como la anterior.
•IC: Costo por mantener Inventario: e.g., interest lost, storage space,
pilferage, obsolescence, etc.
Estrategias de Planeamiento Agregado Puro
Estrategias de Planeamiento Agregado Puro
4. Backlogging:
D(t) P(t)
B(t)
PC WC BC
W(t), O(t), U(t), S(t) = ct
•B(t): Niveles de Atrasos Acumulados
•Costos involucrados:
•PC, WC: igual que el anterior.
•BC: costos por atrasos (servicio, rotura de stock) : e.g., costos de agilización,
penalidades, ventas perdidas (actuales), insatisfacción de los clientes.
D(t)
P(t)
I(t-1)
PC WC
S(t)
SC
W = constante•D(t): Demanda Agregada
•P(t): Nivel de Producción Agregada
•I(t): Nivel de Inventario Acumulado
•B(t): Niveles de Atrasos Acumulados
•Costos involucrados:
•PC: Costos de Producción
•WC: Costo de trabajo regular
•HC: Costos de contratación: e.g., anuncios, entrevistas, capacitación
•FC: Costos de despidos: e.g., compensación, costo social
•BC: costos por atrasos (servicio, rotura de stock)
Esquema general: Restricción 1
BC
I(t)
B(t)
B(t-1)
W(t-1)
H(t)
•W(t): Nivel de Fuerza de Trabajo Requerida
•H(t): Nivel de nuevos contratos
•F(t): Nivel de despidos laborales
•Costos involucrados:
•WC: Costo de trabajo regular
•HC: Costos de contratación: e.g., anuncios, entrevistas, capacitación
•FC: Costos de despidos: e.g., compensación, costo social
Esquema general: Restricción 2
W(t)
F(t)
5P(t)
•P(t): Nivel de Producción Agregada
•W(t): Nivel de Fuerza de Trabajo Requerida
•O(t): Numero de horas extra.
•WD(t): Número de días laborales en el mes t.
Esquema general: Restricción 3
8*WD(t) *W(t)
O(t)