CHAPTER 4

MASTER SCHEDULING

INTRODUCTION

-The master production schedule (MPS)

-Is a plan for the production of individual end items

-It must be achievable and reflect a balance a balance between required and available capacity.

DEVELOPING A MASTER PRODUCTION SCHEDULE

-To maintain the desired level of customer service by maintaining finish good inventory levels or by scheduling to meet customer delivery requirements.

-To make the best use of material, labor and equipment.

-To maintain inventory investment at the required levels.

PRELIMINARY MASTER PRODUCTION SCHEDULE

-To show the process of developing an MPS , an example, is used that assumes the product is made to stock, an inventory kept, and the product is made in lots.

MASTER SCHEDULE DECISIONS

-The MPS should represent as efficiently as possible what manufacturing will make.

-In each of the manufacturing environment make to stock, make to order, and assemble to order master scheduling should take place where the smallest number of product options exists.

MAKE TO STOCK PRODUCTS

-A limited number of standard items are assemble from many components.

-The MPS is usually a schedule of the actual customer orders.

ASSEMBLE TO ORDER PRODUCT

-Many end items can be made from combinations of basic components and subassemblies.

FINAL ASSEMBLY SCHEDULE (FAS)

-Assembly to customer order, I generally planned using a final assembly schedule.

-Master production scheduling is done at the component level.

-The FAS schedules customer order as they are received and is based on the components planned in the MPS.

ENGINEER TO ORDER

-This is a form of make to order (MTO) product.

-The product is designed before manufacturing based on the customer’s very special need.

-A bridge is an example

THE MPS AND DELIVERY PROMISES

-Customer orders are satisfied from inventory.

-In either case, sales and distribution need to know what is available to satisfy customer demand.

-As order are received, they ‘’consume’’ the available inventory or capacity.

-Any part of the plan that is not consumed by actual customer orders is available to promise to customer.

-Using the MPS, sales and distribution can determine the available to promise (ATP).

-This ATP allows delivery promises to be made and customer orders and deliveries to be scheduled accurately.

-The ATP is calculated by adding scheduled receipts to the beginning inventory and then subtracting actual orders scheduled before the next scheduled receipt.

FORMULA ATP

ATP for period 1= On Hand – Customer orders due before next MPS

=100-80

=20 Units

ATP for period 2= MPS scheduled receipts - Customer orders due before next MPS

=100 – (10+10) =80 Units

ATP for period 4 =100-30 =70 Units

PROJECTED AVAILABLE BALANCE

-Our calculation so far have based the projected available balance on the forecast demand.

-Customer orders will sometime be greater than forecast and sometimes less.

-Projected available balance is now calculated based on whichever is the greater.

-For periods before the demand time fence it is calculated as:

PAB =prior period PAB or on-hand balance +MPS-customer orders

-For periods after the demand time fence, forecast will influence the PAB so it is calculated usig the greater of the forecast or customer orders. Thus the PAB becomes:

PB =prior period PAB+MPS- greater of customer orders or forecast.

EXAMPLE:

Given the following data, calculated the projected available balance. The demand time fence is the end of week, the order quantity is 100,40 are available at the beginning of the period.