Proceso de Planeación de Materiales_V4

Proceso de Planeación de Materiales

Querétaro, Qro. a 12 de marzo de 2014

Demanda• “A need for a particular product or component. The demand

could come from any number of sources. At the finished goods level, demand data are usually different from sales data because demand does not necessarily result in sales (i.e., if there is no stock, there will be no sale). There are generally up to four components of demand: cyclical component, random component, seasonal component and trend component.”

APICS Dictionary

Aire Educational Resources - Copyright 2002

DEMAND

Demand

InterplantRequirements

Sources ofdemand

for products or components

DEMANDCOMPONENTS: cyclical random seasonal trend

2 32 2 32 2 3225 15 530

20 25 25 23 21 1920 5 15 25

30 30

2

17

32

15

30

Forecasts (Production & Service)

Available-to-Promise (ATP) Projected Available Balance Scheduled Receipts Customer Orders

Master Production Schedule

Period

1 65432

20

Demand Time Fence

Lead Time Safety Stock Lot Size

330

1MASTER SCHEDULE Item Number A

Demand Time Fence

87

Planning Time Fence

Planning Horizon

Tipos de Demanda

• Demanda Independiente– Demanda generada de forma externa, puede ser

por pedidos de clientes, pronósticos, estacionalidad o tendencias.

• Demanda Dependiente:– Demanda provocada por la explosión de

materiales de un componente padre.

Aire Educational Resources- Copyright 2002

INDEPENDENT DEMANDQ

uant

ity

Time

Safety Stock

DEPENDENT DEMANDSource:components of endproducts assemblies subassemblies components raw materials

TimeQ

uant

ity

OrderQuantity

Lead Time toReplenish

AverageInventory =½ orderquantity +safety stock

The sloped linerepresents thegradualindependentdemand inventoryusage

ED

B

A

Points at which thedependent demanditems are required andused.

Dependentdemanditem stock isreplenished.

Dependent demand is: calculated via BOM explosion need not be forecasted

INDEPENDENT DEMANDSource: customer orders forecastsTypes: finished goods service parts


Stock

ReorderPoints

Qua

ntity

Time

Safety Stock

ReorderPoints


DEPENDENT DEMAND

DEPENDENT DEMANDSource:components of endproducts assemblies subassemblies components raw materials

TimeQ

uant

ity

OrderQuantity


AverageInventory =½ orderquantity +safety stock

The sloped linerepresents thegradualindependentdemand inventoryusage

ED

B

A

Points at which thedependent demanditems are required andused.

Dependentdemanditem stock isreplenished.

Dependent demand is: calculated via BOM explosion need not be forecasted

INDEPENDENT DEMANDSource: customer orders forecastsTypes: finished goods service parts


Stock

Master Scheduling

• “That process where the master schedule is generated and reviewed and adjustments are made to the master production schedule to ensure consistency with the production plan. The master production schedule (the line on the grid) is the primary input to the material requirements plan. The sum of the master production schedules for the items within the product family must equal the production plan for that family.”

APICS Dictionary

MASTER SCHEDULING PROCESS

1. Review the final version of the monthly Production Plan- production rate in terms of product families- monthly time buckets

2. Develop an initial Master Production Schedule- Break down the production plan from monthly into weekly time buckets- From product families into individual end items- Consider on hand inventories- Consider lot sizing and safety stock- Consider desired inventory levels- Consider input from Marketing- customer deliveries- Consider input from Manufacturing - resources availability- Consider input from Finance - budgets

3. Evaluate the feasibility of the MPS by performing a rough-cut-capacity planning process

- are resources available?- simulate alternative plans

4. Publish the final version of the MPS- resources are available- accepted by marketing, manufacturing and finance- accepted master production schedule


MASTER SCHEDULING

ProductionPlan

Rough-cutCapacityPlanning

MaterialRequirements

Planning

MasterProductionSchedule

MPS – Master Production Schedule• “The master production schedule is a line on the master schedule

grid that reflects the anticipated build schedule for those items assigned to the master scheduler. The master scheduler maintains this schedule, and in turn it becomes a set of planning numbers that dries material requirements planning. It represents what the company plans to produce expressed in specific configurations, quantities, and dates. “The master production schedule is not a sales item forecast that represents a statement of demand. The master production schedule must take into account the forecast, the production plan, and other important considerations such as backlog, availability of material, availability of capacity, and management policies and goals.”

APICS Dictionary

MPS

• La programación puede ser concebida de dos formas posibles:– Dominado por el procesador (Capacidad fija)– Dominado por materiales (Capacidad variable)

• Objetivos del MPS:– Balancear suministro y demanda en base al plan de

producción.– Planear eficientemente el uso de los recursos de la compañía

• Entregar el programa maestro al MRP para la explosión de materiales y establecer prioridades para componentes y ensambles.

Demandas del MPS

1 2 3 4 5 6 7 8Pronósticos de venta 100 100 120 120 100 100 100 100Requerimientos intercompañía 50 150 10Necesidades especiales de ingeniería 20Demanda por refacciones 30 30Promociones especiales 80Cambio en inventario seguridad 10 -10Producción anticipada 5 5Totales 130 160 120 260 130 120 185 115

Periodos

MPS

• Rolling Scheduling• Time Buckets• ATP – Available to Promise• PAB – Projected Available Balance• Cumulative Lead Time

Lead Time


MASTER SCHEDULE

This is theMaster ScheduleFormat

2 32 2 32 2 3225 15 530

20 25 25 23 21 1920 5 15 25

30 30

2

17

32

153030


Available-to-Promise Projected Available Balance Scheduled Receipts Customer Orders


Week

1 65432

20

Time Fence


330

2

E(1)LT=1

D(2)LT=4

B(1)LT=1

LEGEND: LT= Lead Time

ALT=2

MASTER SCHEDULE

MasterScheduled

end item

Item Number A

SupplyDemand

Demand Time Fence

87

Planning Time Fence

Cumulative LeadTime for product “A” is 7 weeks.

Tiempo de entrega acumulado (Cumulative Lead Time)

• “The longest planned length of time to accomplish the activity in question. It is found by reviewing the lead time for each bill of material path below the item; whichever path adds up to the greatest number defines cumulative lead time.”

APICS Dictionary


CUMULATIVE LEAD TIME - Syn: aggregate lead time, combined lead time, composite lead time, critical path lead time, stacked lead time

1 2 3 4 5

8 9 10

6 7

1 2

1 2 3 4 5

A

B

C

D

E

A

ED

CB

LeadTimes

A = 3 B = 5 C = 2 D = 2 E = 5 CUMULATIVE LEAD TIME

1 2 543 109876

Horizonte de planeación

• El horizonte de planeación usualmente es mayor que el tiempo de entrega acumulado para facilitar:

– Tamaño del lote de componentes– Control de piso y planeación de la capacidad– Programar proveedores y centros de trabajo


PLANNING HORIZON

Change to MPS very difficult Time Frame: one to

four weeks

Mix change possible pastthe demand time fence

Time Frame: up to thethe products cumulativelead time

System can change the MPS schedule past the planning time fence Time Frame: from one to two years

Planning Horizon

2 32 2 32 2 3225 15 530

20 25 25 23 21 1920 5 15 25

30 30

2

17

32

15

30




Period

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20

Demand Time Fence


330


87

On Hand

Planning Time Fence

Demand Time Fence

Planning Horizon

Time Fence – Barrera de tiempo

• “ A policy or guideline established to note where various restrictions or changes in operating procedures take place. For example, changes to the master production schedule can be accomplished easily beyond the cumulative lead time, while changes inside the cumulative lead time become increasingly more difficult to a point where changes should be resisted. Time fences can be used to define these points.”

APICS Dictionary


TIME FENCE

Change to MPS very difficult Time Frame: one to

four weeks

Mix change possible pastthe demand time fence

Time Frame: up to thethe products cumulativelead time

System can change the MPS schedule past the planning time fence Time Frame: from one to two years

Planning Horizon

2 32 2 32 2 3225 15 530

20 25 25 23 21 1920 5 15 25

30 30

2

17

32

15

30




Period

1 65432

20

Demand Time Fence


330


87

On Hand

Planning Horizon

A policy or guideline established tonote where various restrictions orchanges in operating procedurestake place.

Demand Time Fence

Planning Time Fence

Demand Time Fence• “1) That point in time inside of which the forecast is no longer

included in total demand and projected available inventory calculations; inside this point, only customer orders are considered. Beyond this point, total demand is a combination of actual orders and forecasts, depending on the forecast consumption technique chosen. 2) In some contexts, the demand time fence may correspond to that point in the future inside which changes to the master schedule must be approved by an authority higher than the master scheduler. Note, however, that customer orders may still be promised inside the demand time fence without higher authority approval if there are quantities available-to-promise (ATP).”

APICS Dictionary


DEMAND TIME FENCE (DTF)

2 32 2 32 2 3225 15 530

20 25 25 23 21 1920 5 15 25

30 30

2

17

32

15

30




Period

1 65432

20

Demand Time Fence


330


Demand Time Fence

87

Planning Time Fence

Planning Horizon

On Hand

In the example below, theDemand Time Fenceis 3 periods. This means that inside those 3periods, the Projected Available Balancecalculation excludes the forecasts from the totaldemand. The calculation for the ProjectedAvailable Balance is as follows: (On Hand + Scheduled Receipts or Master Production Schedule) - (Customer Orders)

Past the Demand Time Fence, theProjected Available Balance calculationcan consider total demand as being:1) Forecasts only2) Greater of Forecasts or CustomerOrders3) Sum of Forecasts and Customer OrdersIn the example below, we used as demandthe option 1), forecasts only, to calculatethe projected available balance.

MPS changes notrecommended

Mix changes possible MPS can bechanged

Planning Time Fence

• “A point in time denoted in the planning horizon of the master scheduling process that marks a boundary inside of which changes to the schedule may adversely affect component schedules, capacity plans, customer deliveries, and cost. Outside the planning time fence, customer orders may be booked and changes to the master schedule can be made within the constraints of the production plan. Changes inside the planning time fence must be made manually by the master scheduler.”

APICS Dictionary


PLANNING TIME FENCE - Syn: planning fence

Planning Time Fence

2 32 2 32 2 3225 15 530

20 25 25 23 21 1920 5 15 25

30 30

2

17

32

15

30




Period

1 65432

20

Demand Time Fence


330


87Planning Horizon

Demand Time FenceOn Hand

In the example below, thePlanning Time Fencerepresents the end products cumulative lead time. Thecumulative lead time for Item Number “A” is 7 periods.Caution should be taken when changes are attemptedinside this planning time fence, for there might not beenough lead time to procure the materials at the lowerlevels.

Past the Planning TimeFence, the ProjectedAvailable Balance calculationconsiders only forecasts asdemand.

ATP – Available to Promise

• “The uncommitted portion of a company’s inventory and planned production, maintained in the master schedule to support customer order promising. The ATP quantity is the uncommitted inventory balance in the first period and is normally calculated for each period in which an MPS receipt is scheduled. In the first period, ATP includes on-hand inventory less customer orders that are due and overdue.”

APICS Dictionary


AVAILABLE-TO-PROMISE (ATP)

How do you calculate the available to promise?

First period ATP = ((On Hand + Master Production Schedule) - Customer Orders)

Following period ATP = (Master Production Schedule - Customer Orders)

2 32 2 32 2 3225 15 530

20 25 25 23 21 1920 5 15 25

30 30

2

17

32

153030

Demand Time Fence Planning Time Fence

See: the three different methods of ATP calculations.




Period

1 65432

20

Demand Time Fence


330


87Planning Horizon

In the example below, theAvailable to Promiserepresents the end products uncommittedinventory that is available to thecustomers. It is usually used to help theorder entry function of promising deliverydates to customers.

Note:The ATP calculation usually starts atthe period where a master schedule isdue, and subtracts customer ordersand/or forecasts for the subsequentperiods up to the next masterscheduled receipt.


CUMULATIVE AVAILABLE-TO-PROMISE

How do you calculate the cumulative available topromise?

The example below is for the “without look aheadmethod”:

First period ATP = (On Hand + Master ProductionSchedule) - Customer Orders

Following period ATP = ATP in the previous period +MPS - the the periods backlog.

= 20 + 30 - 25 = 25

2 32 2 32 2 3225 15 530

20 25 25 23 21 1920 5 15 25

30 30

2

17

32

1530

3020 25 40 65




Period

1 65432

20

Demand Time Fence


330


Demand Time Fence

87

Planning Time Fence

Planning Horizon

Note:The cumulative available-to-promise linereflects the cumulative unused availableinventory for future incoming customerorders. Care should be taken to ensure thatthis cumulative number does not get out ofsynch with the master schedule.

Cumulative Available-to-Promise (ATP)

Cus

tom

er O

rder

s &

MP

S

Periods

2515

5

2 4 6

Themaster

schedule30 3030

CustomerOrders

Validación el plan

• RCCP– “The process of converting the master production

schedule into requirements for key resources, often including labor, machinery, warehouse space, suppliers’ capabilities, and, in some cases, money. Comparison to available or demonstrated capacity is usually done for each key resource. This comparison assists the master scheduler in establishing a feasible master production schedule.”

APICS Dictionary

MPS vs Capacidad

• Capacidad disponible > Trabajo programado:– MPS es realizable

• Capacidad disponible < Trabajo programado:– Explorar opciones:

• Programar tiempos extra• Añadir turnos o contratación• Centros de trabajo alterno• Subcontratar

MRP – Material Requirements Planning

• “A set of techniques that uses bill of material data, inventory data, and the master production schedule to calculate requirements for materials. It makes recommendations to release replenishment orders for material. Further, because it is time-phased, it makes recommendations to reschedule open orders when due dates and need dates are not in phase. Time-phased MRP begins with the items listed on the MPS and determines (1) the quantity of all components and materials required to fabricate those items and (2) the date that the components and material are required. Time-phased MRP is accomplished by exploding the bill of material, adjusting for inventory quantities on hand or on order, and offsetting the net requirements by the appropriate lead times.”

APICS Dictionary

MRP – Funciones

• Planear y controlar inventarios– Componentes a ordenar– Cantidades a ordenar– Fecha de entrega

• Planear y controlar liberación de órdenes– Garantizar que las ordenes cumplan fechas de promesa– Mantiene la validez de las fechas de entrega

• Proporciona una carga de órdenes precisas para planeación de la capacidad.

Parámetros del proceso

• Horizonte de planeación• Time buckets - “cubos de tiempo” • Frecuencia de planeación

MRP - Horizonte de planeación

• Tan largo como el Horizonte del MPS.• Para artículos comprados o manufacturados

debe ser por lo menos tan largo como el tiempo de entrega acumulado.

• De no ser así se corre riesgo de expeditar órdenes para cumplir con el plan.

• De no ser suficiente se impactarán artículos de nivel bajo debido a falta de visibilidad en la cobertura.

MRP – Frecuencia planeación

• ¿Cada cuanto se debe de “correr el MRP”?• Cambio neto vs Cambio regenerativo• Impacto de la frecuencia:

– Muy seguido: Nerviosismo al sistema– Muy espaciado: MRP se vuelve impreciso y poco

eficaz

MRP - Entradas

• El MRP requiere de 4 parámetros de entrada:– BOM o lista de materiales– Datos de inventario– Factores de planeación– MPS

MRP - Salidas

• El MRP tiene como salida:– Órdenes planeadas de compra– Órdenes planeadas de producción– Mensajes de acción

• Liberar órdenes• Expeditar órdenes o envíos• Atrasar órdenes o envíos • Cancelar órdenes


FIRM PLANNED ORDER (FPO)

30 30 25 40 25

20 -10 -15 -40 -80-15 25 40

15 15 25 4015 15 25 40

Week

1 65432

E(1)LT=1

D(2)LT=4

B(1)LT=1


ALT=2

1 2 3 4 5 630 30 25 40

MASTER SCHEDULE (Planned Order Releases)Week

Product “A”

MasterScheduledend item

Firm Planned Orderis a technique used mostly with MPS items. It can beused as well for MRP (dependent) items. Essentially, itis a planner’s override of the MRP systemrecommendations. It allows the planner to modify theplanned order due date, release date or quantity. Forexample, if the planner wants to change the plannedorder due in week 3, quantity 15, to week 2, quantity15, he would change the due date of that planned orderand flag it as Firm Planned Order. This means thatwhen we rerun the MRP process, this firm plannedorder will not be modified by the system.

1515

The circled numbers represent thefirm planned order.

Planned orders are MRPsystemrecommendations tocover the netrequirements. Theseplanned orders arecontinually recalculatedwith each new MRP run.Two key pieces ofinformation are used inthis process: lot sizingand lead times.

Gross Requirements

Planned Order Receipts Net Requirements Projected on Hand Scheduled Receipts

Planned Order Releases

20

Item Number Lead Time Safety Stock Lot Size

“B”

Lot-for-lot

1

QAD – Orden en firme


PLANNED ORDER

30 30 25 40 25

20 -10 -15 -40 -80-15 25 40 15 25 40

15 25 40

Week

1 65432

E(1)LT=1

D(2)LT=4

B(1)LT=1


ALT=2

1 2 3 4 5 630 30 25 40

MASTER SCHEDULE (Planned Order Releases)Week

Product “A”

MasterScheduledend item

Planned ordersare MRP systemrecommendationsto cover the netrequirements.These plannedorders arecontinuallyrecalculated witheach new MRPrun. Two keypieces ofinformation areused in thisprocess: lot sizingand lead times.

Planned Orders…. Created by computer can be changed/deleted by computer become gross requirements at the next

level (the planned order release date &quantity)

input to:capacity requirements planning

Gross Requirements

Planned Order Receipts Net Requirements Projected on Hand Scheduled Receipts

Planned Order Releases

20

Item Number Lead Time Safety Stock Lot Size

“B”

Lot-for-lot

1

QAD Orden planeada

Mensajes de acción

BOM

• Una lista de materiales (bill of materials) es una lista de materias primas, sub-ensambles, componentes, partes y las cantidades de cada elemento necesario para manufacturar un producto terminado o artículo padre.

A

F(1)D(1)E(1)D(2)

C(1)B(1)

Part Number Quantity Per A

...B 1 …...D 2 …...E 1

...C 1 …...D 1 …...F 1

Indented bills of materialare used for:

product cost breakdown assembly planning


INDENTED BILL OF MATERIAL

Explosión de materiales

• “Lower Level BOM”– Un material puede aparecer en varios productos

como componente a diferentes niveles de estructura, para consolidar los requerimientos se utiliza el método de nivel mas bajo de estructura.

Datos de Inventario

• Balance de existencias• Cantidades asignadas• Recibos programados• Exactitud recomendada de los registros: 95%

Factores de planeación

• Tamaño de lote• Tiempo de entrega• Inventario de seguridad• Desperdicio (scrap) y utilización (yield)• Múltiplos a ordenar• Políticas de ordenamiento

Exactitud del MRP

• La exactitud del MRP vendrá dada por el producto de los porcentajes de sus parámetros de entrada:– 98% Exactitud Inventario– 98% Exactitud BOM– 100% MPS– 98% Exactitud parámetros de planeación

• 0.98*0.98*0.98*1=0.9411 ≈ 95%

QAD – MRP

QAD – Planeación Artículos

• Programa Maestro:– Bandera que indica al sistema si deberá mantener una

planeación asistida del artículo• Órdenes planeadas:

– El sistema colocará órdenes planeadas de este número de parte

• Límite de tiempo:– Cantidad en días que se le indican al sistema que no

realice correcciones automáticas al plan de materiales para este artículo

• MRP Requerido:– Bandera que indica si el artículo se incluirá en el

próximo MRP regenerativo.• Politica de ordenamiento

– Parametro que le indica al MRP el esquema de solicitud del artículo en órdenes:

• LPL/LFL lote por lote• POQ (Period Order Quantity)• FOQ (Fixed Order Quantity)

• Cantidad a ordenar:– Campo empleado cuando política de

ordenamiento es FOQ• Cantidad Lote

– Campo actualizado desde Mnto Fórmula/Proceso• Periodo a ordenar

– Campo utilizado cuando política de ordenamiento es POQ

• Inv. Seguridad– Inventario mínimo a mantener del artículo

• Tiempo de seguridad– Parametro empleado cuando es difícil mantener

un inventario de seguridad.• Punto de reorden:

– Valor que indica cuando se deben solicitar órdenes para mantener el stock deseado. Este campo se emplea en artículos que no utilizan MRP.

• Rev.– Revisión de ingeniería del artículo

• Política de Salida– Indica si el sistema solicitará la salida del material

del inventario en órdenes de producción o si únicamente incluirá el costo del producto pero no cantidades físicas del mismo.

• Comprador/Planeador– Campo que indica la persona responsable de

administrar el artículo• Proveedor

– Indica el proveedor preferido para este artículo (Sólo en artículos tipo “P”)

• Compra/Manufactura– Indica la procedencia del artículo, los valores

utilizados por el sistema son: P, M, D, R, C, L, W, F.

• Tipo de configuración– Indica si es un artículo compuesto por productos

opcionales y obligatorios (ATO) o si es un kit (KIT)• ATP Forzado

– Indica si el sistema manejara capacidades y productos disponibles para promesa o si restringirá la creación de órdenes sin materiales disponibles.

• Fantasma– Ensamble transitorio

• Orden mínima• Orden máxima• Orden múltiplo• Rendimiento base op.

– Indica si el % de rendimiento se utilizará el monto en el maestro de artículos o si este campo se utilizará de la ruta de manufactura.

• Tipo de TME– Tipos de Transferencia de material empresa

• NO-TME: Embarcar artículos directamente a cliente• TRANSBORDAR: Intermediario de logística para CEDI• ENTREGA DIRECTA: Intermediario de logística para

clientes.

• Código de RED– Ruta de distribución para artículos tipo “D”

• Código de Ruta– Ruta estándar para manufacturar el artículo este

parámetro puede modificarse en el mantenimiento de órdenes de trabajo

• LDM/Cód Fórm– Lista de materiales estándar para el producto

• Metodo de abastecimiento– Indica si el artículo se surtirá por órdenes

estándar o por Kanban.

“Nuestra actitud hacia la tecnología depende de si nos impresionan sus maravillas”.

Proceso de Planeación de Materiales_V4

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