Download - CH 2 IE 304 MPS
-
7/29/2019 CH 2 IE 304 MPS
1/28
IE 304
Chapter 2
MASTER PRODUCTION
SCHEDULING (MPS)
1
-
7/29/2019 CH 2 IE 304 MPS
2/28
Mid and Short Range Planning Details
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 timesComponent 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)
2
-
7/29/2019 CH 2 IE 304 MPS
3/28
3
They
combine
Eventually, the time comes when individual end item products and services
must be scheduled at specific work centers.
This is accomplished by master scheduling
Which means, producing a SUPPLY PLAN (a time table including quantities) to produce specific
items or provide specific services within a given time period.
Aggregate Production
& Capacity Plans
Products into
product groups.
Demand into
monthly totals.
Personnel
Requirements
across departments
Which alltogether
reflect Top Management
Decisions.
Master Scheduling
-
7/29/2019 CH 2 IE 304 MPS
4/28
4
THE ENVIRONMENT
Before describing the activities involved in creating and managing
the MS,
we need to examine the different organizationalenvironments inwhich master scheduling takes place.
THESE ENVIRONMENTS ARE DETERMINED BY
the companys STRATEGIC RESPONSESto;
and
Thus, a COMPETETIVESTRATEGY evolves...
the INTERESTS of
CUSTOMERS
the ACTIONS of
COMPETITORS
-
7/29/2019 CH 2 IE 304 MPS
5/28
5
Preemptive Tactics
There may be ways to manage the extremes
of demand:
Discount prices during the valleys.... have asale
Peak-load pricing during the highs .... electric
utilities, airline tickets
-
7/29/2019 CH 2 IE 304 MPS
6/28
6
Objectives of MPS
Determine the quantity and timing of
completion of end items over a short-range
planning horizon.
Schedule end items (finished goods and
parts shipped as end items) to be completed
promptly and when promised to the
customer.
Avoid overloading or underloading theproduction facility so that production
capacity is efficiently utilized and low
production costs result.
-
7/29/2019 CH 2 IE 304 MPS
7/28
7
l The rules for scheduling
No Change
+/- 5%
Change
+/- 10%
Change
+/- 20%
Change
Frozen FirmFull
Open
1-2
weeks2-4
weeks
4-6
weeks6+weeks
Time Fences
-
7/29/2019 CH 2 IE 304 MPS
8/28
8
Time Fences
The rules for scheduling:
Do not change orders in the frozen zone
Do not exceed the agreed on percentage
changes when modifying orders in the other
zones
Try to level load as much as possible Do not exceed the capacity of the system when
promising orders.
-
7/29/2019 CH 2 IE 304 MPS
9/28
9
Developing an MPS
Using input information
Customer orders (end items quantity, due dates)
Forecasts (end items quantity, due dates)
Inventory status (balances, planned receipts)
Production capacity (output rates, planned
downtime)
. . . more
-
7/29/2019 CH 2 IE 304 MPS
10/28
10
Developing an MPS
Schedulers must:
estimate the total demand for products from all
sources assign orders to production slots
make delivery promises to customers, and
make the detailed calculations for the MPS
-
7/29/2019 CH 2 IE 304 MPS
11/28
Master Production Schedule
Provides basis for:
Making good use of manufacturing resources
Making customer delivery promises
Resolving tradeoffs between sales and
manufacturing
Attaining strategic objectives in the sales andoperations plan
11
-
7/29/2019 CH 2 IE 304 MPS
12/28
What is Master Production
Scheduling?
Start with Aggregate plan
(Aggregate Sales & Ops Plan) Output level designed to meet targets
Disaggregates
Converts into specific schedule for each item
12
-
7/29/2019 CH 2 IE 304 MPS
13/28
The (Master) Production Scheduling Problem
MPS
Placed Orders
Forecasted Demand
Current and Planned
Availability, eg.,
Initial Inventory,
Initiated Production,
Subcontracted quantities
Master Production
Schedule:
When & How Much
to produce for each
product
Capacity
Consts.
Company
Policies
Economic
Considerations
Product
Charact.
Planning
Horizon
Time
unit
Capacity
Planning
13
-
7/29/2019 CH 2 IE 304 MPS
14/28
14
Example: Master Production
Scheduling
Arizona Instruments producesbar code
scanners for consumers and other manufacturers
on aproduce-to-stockbasis. The productionplanner is developing an MPS for scanners for the
next 6 weeks.
The minimum lot size is 1,500 scanners, and
the safety stock level is 400 scanners. There are
currently 1,120 scanners in inventory. The
estimates of demand for scanners in the next 6
weeks are shown on the next slide.
-
7/29/2019 CH 2 IE 304 MPS
15/28
15
Example: Master Production Scheduling
Demand Estimates
CUSTOMERS
BRANCH WAREHOUSES
MARKET RESEARCH
PRODUCTION RESEARCH
500
200
0
10
1
0
50
300
1000
0
0
500
400
2 3 4
200
000
300500
0100
700
65
1000
200
WEEK
-
7/29/2019 CH 2 IE 304 MPS
16/28
16
Example: Master Production Scheduling
ComputationsCUSTOMERSBRANCH WAREHOUSES
MARKET RESEARCH
PRODUCTION RESEARCH
500
200
0
10
1
0
50
300
1000
0
0
500
400
2 3 4
200
000
300500
0100
700
65
1000
200
WEEK
TOTAL DEMAND
BEGINNING INVENTORY
REQUIRED PRODUCTION
ENDING INVENTORY
710
1120
0
410 560
1500
410
1350
1160
1500
900
560
700
1250950460
4601160
150015000
1010 1200
950
-
7/29/2019 CH 2 IE 304 MPS
17/28
-
7/29/2019 CH 2 IE 304 MPS
18/28
18
Rough-Cut Capacity Planning
As orders are slotted in the MPS, the effects
on the production work centers are checked
Rough cut capacity planning identifiesunderloading or overloading of capacity
-
7/29/2019 CH 2 IE 304 MPS
19/28
19
Example: Rough-Cut Capacity Planning
Texprint Company makes a line ofcomputer printers
on a produce-to-stock basis for other computer
manufacturers. Each printer requires an average of 24
labor-hours. The plant uses a backlog of orders to allow alevel-capacity aggregate plan. This plan provides a weekly
capacity of 5,000 labor-hours.
Texprints rough-draft of an MPS for its printers is
shown on the next slide. Does enough capacity exist toexecute the MPS? If not, what changes do you
recommend?
-
7/29/2019 CH 2 IE 304 MPS
20/28
Example: Rough-Cut Capacity Planning
Rough-Cut Capacity Analysis
PRODUCTION (MPS) 100 200 200 280250
1 2 3 4 5
WEEK
TOTAL
1030
LOAD 2400 4800 4800 67206000 24720
CAPACITY 5000 5000 5000 50005000 25000
UNDER orOVER LOAD 2600 200 200 17201000 280
20
-
7/29/2019 CH 2 IE 304 MPS
21/28
-
7/29/2019 CH 2 IE 304 MPS
22/28
Disaggregation
Working with aggregate units facilitate intermediate planning.
But to put this plan into action we should translate it,
decompose it, disaggregate it and state it in terms of actual units
of products and for a shorter period
Aggregate planning was for 12 or more months. Now we should break it down into shorter periods, say 2-3 months.
Disaggregation;
Breaking down the aggregate plan into specific products.
From aggregate product to real specific products.
Based on the specific products, then calculate detail of manpower,
material and inventory requirements.
22
-
7/29/2019 CH 2 IE 304 MPS
23/28
Disaggregation
Aggregate PlanMonth Jan Feb Mar
lawn Mower 200 300 400
Master Schedule
Push 100 100 100Self-propelled 75 150 200
Riding 25 50 100
Total 200 300 400
Total of aggregate and
disaggregate products are notnecessarily equal
23
-
7/29/2019 CH 2 IE 304 MPS
24/28
-
7/29/2019 CH 2 IE 304 MPS
25/28
Master Schedule
Aggregate plan: 12 months.
Master schedule: 12 weeks.
Master schedule is updated every 2 week.
Therefore, it is on a rolling basis, always we
have a disaggregated plan for the next 12
weeks.25
-
7/29/2019 CH 2 IE 304 MPS
26/28
Final Assembly Schedule
Master Production schedule is anticipated
build schedule
FAS is actual build schedule
Exact end-item configurations
26
-
7/29/2019 CH 2 IE 304 MPS
27/28
Schedule Stability
Stable schedule means stable component
schedules, more efficient
No changes means lost sales
Frozen zone- no changes at all
Time fences
>24 wks, all changes allowed (water)
16-23 wks substitutions, if parts there (slush)
8-16 minor changes only (slush)
< 8 no changes (ice)
27
-
7/29/2019 CH 2 IE 304 MPS
28/28
QUESTIONS?
28