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Planning and Control in General
• What is planning and control?
• What is difference between planning and control?
• How does the nature of demand affect planning and control?
• What is involved in planning and control?
Concepts We need to Understand
• dependent demand and independent demand
• make-to-stock, make-to-order, resource-to-order
• loading, sequencing, scheduling and monitoring
• pull and push systems
Planning and Control– Reconcile Supply and Demand
Supply of products
and services
Planning and
Control
Demand for products and
services
Operation resources
Required time, quantity and
quality of products and
services
Customer requirement
s
Planning is deciding
Control is
what activities should take place in the operation and their quantities
when they should take place
what resources should be allocated to them
understanding what is actually happening in the the operation
deciding whether there is a significant deviation from what should be happening
(if there is deviation) changing resources in order to affect the operation’s activities
Planning and Control
Significance of planning or controlT
ime
ho
rizo
nH
ou
rs/d
ays
Day
s/ w
eeks
/ mo
nth
sM
on
ths/
year
s
Medium-term Planning and ControlUses partially dissaggregated demand forecasts
Determines resources and contingencies
Objectives set in both financial and operations terms
Long-term Planning and ControlUses aggregated demand forecasts
Determines resources in aggregated form
Objectives set in largely financial terms
Short-term Planning and ControlUses totally dissaggregated forecasts or actual demand
Makes interventions to resources to correct deviations from plans
Ad hoc consideration of operations objectives
PLANNING
CONTROL
Planning and control needs….
Information on Demand levels
Information on Resources
Dependent and Independent Demand
Dependent demande.g. input tyre store in car plant
Demand for tyres is governed by the number of
cars planned to be made
Demand for tyres is largely governed by
random factors
ACE TYRES
Independent demande.g. tyre fitting service
Dependent and Independent Demand-defining them
Demand = forecasts + known orders
• Dependent demand – the demand is mainly coming from known orders.
• Independent demand – the demand is mainly coming from forecasted figures.
P and D for the Different Types of Planning and Control
Purchase Make Deliver
DP
Purchase Make Deliver
Purchase Make Deliver
DP
Make to stock
Make to order
Resourceto order
PD
Where D is demand time and P is total throughput time.
MAKE TO STOCK
Purchase
And … – ‘make-to-stock and assemble-to-order’ Planning and Control
Make Parts Assemble Deliver
DP
Order
ASSEMBLE TO ORDER
Resource-to-order
Make-to-order
Make-to-stock
Dependent Demand
Independent Demand
Each product or service large compared with total capacity of each operation
Each product or service small compared with total capacity of each operation
Planning and Control Activities
Sequencing
MonitoringScheduling
Loading
Are activities going to plan?
When to do things?
In what order to do things?
How much to do?
Loading – the amount of work allocated in terms of time
Maximum time available
Normal time available Not worked
Planned time available
Planned running time Set-ups
Available time
Actual running time Down time
Sequencing – the order in which the work will be tackled
Various sequencing rules are used in operations:
- Customer priority;- Due date;- LIFO - last in first out;- FIFO - first in first out;
Longest operation time first;- Shortest operation time first.-
Scheduling – the details on starts and finishes of jobs
Gantt Chart • Created by American industrial engineer Henry
Gantt (1861-1919)• In a table format• Two dimensions-jobs (tasks) and time• the horizontal axis is directly proportional to time• Easy to draw and use for a day-to-day plan
JOB Mon 6th
Tue7th
Wed 8th
Thur 9th
Fri 10th
Mon 13th
Tue 14th
Table
Shelves
Kitchen units
Bed
Time now
Scheduled activity time Actual progress
Gantt Chart for Job Progress
JOB Mon 6th
Tue7th
Wed 8th
Thur 9th
Fri 10th
Mon 13th
Tue 14th
Wood preparation
Assembly
Finishing
Paint
Time now
Scheduled activity time
Actual progress
T
B
B T
S K
S S S
K
KTS
B T
Gantt Chart for Work Centers
Non- productive time
Pull and Push Control
CENTRAL OPS. PLANNING AND CONTROL SYSTEM
Work centre
DEMANDWork centre
Work centre
Work centre
Instruction on what to make and where to
send it
FORECAST
PULL CONTROL
Work centre
Work centre
Work centre
Work centre DEMAND
Request Request Request Request
Delivery Delivery Delivery Delivery
PUSH CONTROL
KNOWN ORDERS
True or False
If the demand of a product is mainly from forecasts, we call this type of demand independent demand.
Resource-to-order planning and control is used for dealing with independent demand.
Time is the only important aspect in planning and control activities
Summary
• The three dimensions of planning and control are:
timing, quantity (volumes) and quality• The difference between dependent and independent
demand is the % of known orders or forecasts of the total demand
• Types of planning and control are:
‘make-to-stock’, ‘make-to-order’, ‘resource-to-order’, ‘make-to-stock and assemble- to-order’
• Planning and control activities are:
loading, sequencing, scheduling and monitoring