Functions of Production Planning and Control.pdf

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1. 1
FUNCTIONS OF PRODUCTION
PLANNING AND CONTROL
The highest efficiency in production is obtained by manufacturing the re
quired quantity of product, of the required quality, at the required time, by the
best and cheapest method."" To attain this target, management employs
production planning and control, the tool that coordinates all manufacturing
activities.
Production consista of a sequence of operations that transform materials
from a given to a desired form. The transformation may be done in one or in a
oombination of the following ways:
1. Transformation by disintegration, having essentially one ingredient as
input and producing several outputs. This transformation is almost invariably
BOOompanied by changes in the physical shape of the input, such as changes in
the physical state or in the geometrical form. Examples: producing lumber in a
BaWnill, rolling steel bars from cast ingots, making components from standard
ized naterials on mnachine tools, oil-oracking which yields several products, eto.
2. Transformation by integration or assembly, using several components as
inputs and obtaining essentially one product as output. Examples: producing
machines, furniture, household appliances, automobiles, radio and television
sets, alloys, sulfuric acid, concrete, eto.
3. Transfornation by service, where virtually no change in the object under
0onsideration is perceptible but where certain operations are performed to
change one of the parameters which define the object. This may include: opera
tions for improving the tensile strength, density, crystallographic structure,
weAr, or other mechanical properties of the object; operations that change its
locality or state by transportation or handling means; maintenanoe operations.
Examples: sizing and coining in press work, servicing and light repairs of auto
mobiles, losding and unloading of trucks, ete. Many pure service operations are
Alford, L. P., and Bsngs, J. R., Production Handbook, Ronald Press Co., 1952 (a lator
edition, edited by Carson, G. B., was published in 1958.)

2. 2 Production Planning and Control
not considered to be part of industry, but-the planning and control of sue
operations is basically similar to thoBe of industrial operations, By analogy orf
could say that the highest efficienoy in servicing is obtained by processingh
through the service station the required volume, offering the required qualit,
at the required time, by the best and cheapest method,"
The four factors mentioned abovenamely; quantity, quality, time, an
price-encompass the production system, of which production planning anM
control is the brain. Three distinct stages comprise every activity in such
system: planning, operations, and control.
di
Planning begins with an analysis of the given data, on the basis of which Co
scheme for the utilization of the firm's reso urces oan be outlined so that thP
desirable target may be most efficiently attained. The production plan sets su
targets for the various departments in terms of predetermined time periods, an re
these subtargets are so defined that in achieving them the over-all aim
realized.
Operations are performed in accordance with the details set in the productio R
plan.
Control initiates and supervises operations with the aid of a control mechanisr
that feeds back information about the progress of the work. This mechanism
also responsible for subsequently adjusting, modifying, and redefining plans an
targets, in order to ensure the attainment of the first goal.
Hence, production planning and control may be summarily defined as th
direction and coordination of the firm's material and physical facilities towar
the attainment of prespecified production goals, in the most efficient availabl
way. In its capacity as the brain and the central nervous system of the produc E
tion program, production planning and control is responsible for having avail
able every part and assembly at the right time at the right place, in order ts
ascertain progress of operations according to a predetermined time and plac t
schedule. Specifically, the functions of production planning and control (se o
Fig. 1-1) can be classified in ten categories.
Materials
Methods
Raw materials, as well as standard finished parts and semifinished products
must be available when required, to ensure that each production operation wil im
start on time. Duties include the specification of materials (both with respect to
dimensions and quality), quantities and availability, delivery dates, standardiza
tion and reduction of variety, procurement and inspection. This function als
covers the procurement of semifinished products from subcontractors.
The purpose of this function is to analyze possible methods of manufactur
and to try to define the best method compatible with a given set of circu
stances and facilities. This analysis covers both the general study and selecti

3. n of produotion processes for the manufacture of components or assemblies and
n, the detailed development and specifcations of methods of application.
y Such a study results in determining the sequence of operations and the
division of the product into assemblies and subassemblies, modified by the
limitations of existing layout and work low.
b
bt Routing
Machines and equipment
nd
Once the over-all methods and sequence of operations have been laid down,
m
each stage in production is broken down to define each operation in detail, after
le
Functions of Production Planning and Control 3
Methods of manufacture have to be related to available production facilities,
coupled with a detailed study of equipment replacement policy. Maintenance
policy, procedure, and schedules are also functions connected with managerial
responsibility for equipment, since the whole problem of breakdowns and
reserves can be seriously reflected in halts in production. Tool management, as
well as problems both of design and economy of jigs and fixtures, constitutes
some of the major duties of production planning and control.
which the issue of production orders can be planned. Routing prescribes the
fow of work in the plant and is related to considerations of layout, of temporary
storage locations for raw materials and components, and of materials handling
1 systems. Routing is a fundamental production function on which all subsequent
planning is based.
c. Estimating
0
When production orders and detailed operation sheets are available with
t specifications of feeds, speeds, and use of auxiliary attachments and methods,
the operation times can be worked out. This function involves the extensive use
of operation analysis in conjunction with methods and routing, as well as work
measurement, in' order to set up performance standards. The human element
figures prominently in work measurement because it is sensitive to Bystems of
work ratings and wago incentive schemes. Hence it may consequently relect in
a wide scatter of operation times and in unduly large fluctuations and perhaps
instabilities in time schedules.
a Loading and scheduling
Machines have to be loaded according to their capability of performing the
given task and according to their capacity. Machine loading is carried out in
conjunction with routing, to ensure smooth work fow, and with estimating, to
Cnsure that the prescribed method, feeds, and speeds are best utilized. Schedul
hg is perhaps the toughest job facing a production manager because it deter.
mines the utilization of equipment and manpower and hence the effciency of
the plant. Scheduling must ensure that operations are properly dovetailed, that

4. Production Planning and Control
8emifiniahed componenta arrive at their next etation in time, that aaembi
work in not delayed, and that on the other hand the plant in not unnecensari)
loaded both phyaioaMy and finanoially with work in prooens, i.e., with sem
finiahed componenta waiting for their next operation. This calla for a oAref
analysia of prooeuu capacities, ao that Mlow rates along the various produetio
linea oan be suitably ooordinated, In machine londing, appropriate allowanc
for setup of machines, procesa adjustmenta, and maintenanoe down timne hay
to be made, and these allowances form a vital part of the data constantly use
by the soheduling funotion.
Dispatching
This function is concerned with the exeoution of the planning funotions, Di
patching is "the routine of setting productive aotivities in motion, through n
lease of orders and instructions and in accordanco with proviously planned tim
and sequences as embodied in route sheets and londing schedules.'" Dispatchin
authorizes the start of produetion operations by releasing materials, con
ponents, tools, fixtures, and instruction aheeta to the operator, and ensures th
material movement is carried out according to the planned routing sheets an
to schedules,
Expediting
This control tool is the exeoutive arm that keep8 a close watch on the progres
of the work. Expediting, or "follow-up'" or "progress" as it is sometimes calle
is a logioal step after dispatching. Dispatching initiates the execution of pro
duction plans, wherens expediting maintains them and sees them through to the
successful completion. This funetion has to keep close liaison with scheduling, i
order to provide effieient feedback and prompt review of targets and schedule
Inspection
Another major control function is that of inspeotion, Although the oontrol
quality is often detached from the produetion planning and control department
its findings and criticisms are of supreme importance both in the execution o
ourrent plans and in the planning stage of future undertakings, when th
limitations of processes, methods, and manpower are known. These limitation
can form a basis for further investigations in evaluating, with the view t
improving production methods or indicating the cost implications of quality
the design stage.
Evaluating
Perhaps the most neglected function, but an essential link between contro
and future planning, is that of evaluating. The executive tasks of dispatohn
and expediting are concerned with the immediate issues of production and wi
Ibid.

5. measures that will ascertain the fulfllment of set targete. Valuable information
is gathered in this process, but the feedback mechanism is rather limited in
nature and unless provisiðn is made so that all this acoumulated information can
be properly digested and analyzed, valuable data may be irretrievably lost. This
is where the evaluating function comes in: to provide a feedback mechanism on
a longer term basis 8o that past experience can be evaluated with the view to
improving utilization of methods and facilities. Many firms consider this
function important enough to divoroe part of it from production planning and
control and to establish it as a separate department in its own right, in which
wider aspects of production management can be studied, using modern tools of
operations research. Whatver the scope of evaluating in the production plan
ning and.control department, this process is an integral part of the control
function.
The ten functions were listed above in the order of their operation and are
Rfurther discussed in Chapter 3. As shown in Fig. 1-1, they are related to three
stages: proplanning, planning, and control.
Production development
and design
n
Sales forecasting and
estimating
roFactory layout
Equipment policy
e Pre-planning production
Functions of Production Planning and Control
Feedback
-Preplanning
Planning
Materials
Resources Methods
The 4 M's
Succession of functional responsibilities
Focilities
Machines
and Man
power
Planning
Routing
Estimating
7
Dispatching)
|Scheduling)
Inspection
Expediting
10
Evaluating
Control
Figure 1-1. The ten functions of production planning and control cyele.
Preplanning
This covers an analysis of data and outline of basio planning policy based on
osales reports, market research, and product development and design. On the
n broad aspects of planning, this stage is concerned with problems of equipment
t policy and replacement, new processes and materials, layout, and work flow.
Preplanning production as a production planning and control responsibility

6. Production Planning and Control
is also preocoupied with collecting data on the "4 M's," i.e., on materials, e
methods, machines, and manpower, mainly with respect to availability, scope,
and capacity.
Planning
When the taalk has been specifed, & thorough analysis of the "'4 M's" is firet t
undertaken to select the appropriate materials, methods, and facilities by means s
of which the work can be accomplished. As already mentioned, this analysis is r
followed by routing, estimating, and scheduling. The more detailed, realistic, g
and precise the planning, the greater conformity to schedules achieved during
production, and subsequently the greater the efficiency of the plant. There are
two aspects of planning: a short-term one, concerned with immediate production
programs, and a long-term phase, where plans for the more distant future are
considered and shaped. Prominent planning functions are those dealing with
standardization and simplification of products, materials, and methods.
Control
The ten functions of production planning and control were related in what
might be regarded as a chronological order in the production procedure, which
will be further discussed in Chapter 3. It is important to stress, however, that
there is a very strong connection and interdependence between production
planning and control and other industrial engineering functions, 8ome of which
are briefly described below.
This stage is effeoted by means of dispatching, inspection, and expediting.
Control of inventories, control of scrap, analysis of work in process, and control t
of transportation are essential links of this stage. Finally, evaluation takes place s
to complete the production planning and control cycle. Professor Norbert c
Wiener has said of the social system that it is an organization like the indi.
vidual: that it is bound together by a system of communications: and that it has T
a dynamics, in which circular processes of a feedback nature play an important C
part."3 If this is true of the social system, it is certainly true of the production
system. Once the main policies have been defined by management, produc
tion planning and control is the director and coordinator of the plant production
operations, havinga similar funotion to that of a brain coordinating an animal's
nervous system. The control functions have a very important role in providing
the main souroes of feed back information to ensure necesary corrective actions.
Effective communication systems are prerequisites to efficient control and are
therefore of great concern to produotion planning and control.
Plant Layout
f
a
Norbert Wiener, Cybernetics, John Wiley & Sons, 1948.
1
Layout not only affects the allocation of machines to perform given tasks,
but it may also become an important factor at the design stage in selection o
production processes. A rigid layout may hamper the integration of additionals

7. Functions of Production Planning and Control 7
equipment in a specifio production center, either through lack of space or
limited mobility of the equipment. This may lend to long lines of transportation,
which inerease the total production costs and the amount of work in proces8.
On the other hand, when there is little choice between processes, machine8, or
sequences of operations, changes in plant layout must often be undertaken in
the light of production planning and control requirements, in order to achieve a
satisfactory work flow. Thus, production planning and control is afected by the
restrictions imposed on the system by the layout, and at the same time it may
greatly contribute through evaluation to modifications in layouts.
Simplifleation and Standardization
Production of different components, models, or products leads to a demand for
different types of materials and methods of fabrication. At the various stages of
manufacture, variety may therefore occur in materials, bought-out parts, manu
factured components, minor and major assemblies, or finished products as well
as in processes, methods of manufacture, tools, jigs and fixtures, machines, eto.
Simplification and standardization are functions which aim at defining a limited
variety of different types so that the basio requirements are satisfied and
the efficiency of the plant is increased. Most aspects of implifcation and
standardization are the joint responsibility of several departments; e.g., the
question of limiting the variety of finished products would involve the sales
department, production departments, and the design ofice, while questions
relating to simplification of materials would also include inventory control
considerations and perhaps involve the researoh and development department.
Some aspects of simplification and standardization are the major responsibility
of the production planning and control department, such as problems relating
to machines and methods.
Time and Motion Study
This feld is closely allied to efficient utilization of manpower and to scheduling
problems. Time and motion study consists of two fields of activity: operation
analysis and work measurement.
1. Operation analysis or method study, which--as the name suggests
consists of evaluation, selection, and development of an efficient method to
perform a given task. Operation analysis is concerned both with problems of
limited scope (such as operator's work-place layout, an activity study of a gang
of operators, or correlation of machine-operator activities) and over-all studies
of the process, in which all aspects of routing, plant layout, and scheduling may
play an important role.
2. Work measurement, which is concerned with establishing standard times
for the various operations in the process for the estimating function in produc
tion planning. As already mentioned, no scheduling can even be attempted before
8ome data on performance times become available.

8. 8 Production Planning and Control
From the foregoing remarks it should be appreciated that time and motio
study is employed both at the planning and the control stages., Development of
methods and informttion regarding the measurernent of processing times ca,
be obtained in two ways:
(i) By synthesis, based on past experience of similar circumstances, where the
same processes were employed. Synthesis is an important tool at the plannin,
stage.
(i) By analysis of an existing production n1ethod and measurement of
operation times, when the process is already in action. This obviously belongs t
the control stage, and information gathered in this way provides a basis fo
replanning and readjusting of production schedules, when these are proved to be
unrealistic, and for data required for future synthesis.
Although these two distinct functions of time and motion study are employed
at different stages of production planning and control and for different purposes
they share the same philosophy, the same approach, the same techniques, and
even if they can be divorced in time, they are essentially integral parts of the
same field.
Inventory Control
The importance of materials availability at the various stages of productior
necessitates a mechanism of inventory control and stores organization. Inven
tories are a financial burden on the plant and management of stores may be very
costly. Inventory control is sometimes a very complex function, as its policies
are not dictated by internal needs and considerations alone but by external
factors governing the purchasing of materials, such as vendors' offers and terms.
market availa bility, transportation problems, and eredit terms. These external
factors may infiuence both quantities and delivery dates of materials and com
ponents and have to be taken into acoount by any inventory control mechanism
Production planning and control is a management tool, employed for the
direction of the manufacturing operations and their coordination with other
activities of the firm. In the production system, which is primarily defined by the
dimensions of quantity, quality, time and price, the functions of production
planning and control comprise:
Materials (procurement, stook control, issue)
Summary
Methods (processes, operations and their sequence)
Machines (allocation and utilizátion)
Manpower (availability)
Routing (Aow of work)
Estimating (operation times)
Scheduling (planning the production timetable)

9. Dispatohing (authorizing the start of operations)
Expediting (follow-up)
Evaluating (asmeuing performanoe effectivenenn)
Punctiona of Production Planning and Control
References
The work of produotion planning and control is closely interwoven with other
industrial engineering functions, mainly those of plant layout, equipment
policies, time and motion study, simpliicntion, and standardization.
Carson, G. B. (ed.): Production Handboolk (Ronald Press, 1958).
Kimball, D. 8., and Kimball, D. 8., Jr.: Principlea of Induatrial Organization
(MeGraw.Hill, 1947).
1945).
Lansburgh, R. H., and Spriegel, W. R.: Industrial Management (John Wiley & Sons,
9
Taylor, F.: Prinoiples of Induatrial Management (Harpor & Brothors, 1911).
Weiner, Norbert: Oybernetica (John Wiley & Sons, 1948).
Problems
(The reader may find that reading the first four chapters may be helpful before
attempting the following problems,)
1. Analyze the importanoo of oach of the funetions of production planning and con
trol by discussing what would happen if each one in turn were deleted.
2. Scheduling is a planning function and expediting & control function. In a small
firm it was proposed to allocate both responsibilities to one person. Would you
approve of such a schermo?
3. Analyze tho following statemonts on the placo of work measurement in produc
tion planning and control:
(1) Work measurement can be carried out only when the process is in
operation, and not at the planning stage. Hence work measurement is
a control function for the purpose of computing bonuse8, but as data
about operation times are not available at the planning stage, schedul
ing is a Buperfluous funotion.
(ii) Scheduling is eB8ential in order to facilitate the control of load distribu
tion on the plant. Work mneasurement must therefore be a planning
function, carried out on a "pilot plant" basis, all the operations and
methods being tried out and measured quantitatively before the begin
ning of production.
(ii) UnleRs work mensurernent is carried out under nornal operating
conditions, resulta aro likely to be erroneous; hence measurernent at
the planning stage must be ruled out. On the other hand, scheduling
must be performed before production starts. Therefore work measure
ment is not practical and is just a waste of time.
4. When aaked to express his opinion, a foreman in charge of a machine tool ahop
said: "Why bother about produotion planning and control? Most of it consists
of too much paper work, which has little bearing on reality. In our firm each
foreman responsible for a section gets his instructions once a month together
with drawings of the parts to be machined. It is then the foreman's responsibility

10. Producion Planning and Control
lo cdo all the routing, ost imating, and machine loading within his section. When
oach task is flniahed, the production department is notified. If the parte have to
udergo additionat operations in another section during the same month, an
ONter s iBsued to transfer the parts to that section. If not, the parts wait until
the next cdate for monthly allocation of tasks. The system is snooth and efficient
-and it works".
Suppose you were assigned the task of analyzing the present system in order
to determine its effectiveness. How would you set about doing it?
,which is situated
3. A transport department of a firm is located at its headquarters,
three miles from the main production plant and about ten miles from the main
stores, all three places lying approximately on a straight line. The transport
department has to move personnel between all three cen ters, supply the plant
with materials from the store, and renove finished products from the plant to
the store; it also moves fnihed goods to the railroad station, which is situated
about twenty miles either from the plant or from the store. These commitments
may be classified as follows:
(a) Ten trucks are required on Mondays and Thursdays to transport goods
to the railroad station. The trucks finish unloading by lunch time.
(b) Two truck loads are sent every day to move finished goods from the
plant to the store.
(c) Six truck loads are sent every second day to move materials from the
store to the plant.
(d) Personnel transport is carried out in passenger automobiles ; orders are
sent at randon to the transport department, where all these automo
biles are centralized.
The problems that have to be analyzed are:
(i) Should the transport department be centralized, with all the vehicle
fleet and its maintenance garage situated at headquarters?
(iü) What is the best way to schedule removal of materials and finished
goods?
(ii) Supposing that commitment (a) cannot be changed but commitments
(b) and (o) can be conveniently distributed during the week (assuming
a five-day week), how many trucks are required, if experience has shown
that one truck is often marked down for repairs or maintenance
(iv) Should trailers be purchased to relieve the load on the trucks?
(v) What procedures should be adopted to cater for passengers transporta
tion under commitment (d)?
How would you set about tackling these problems, what additional infor
mation do you require, how would you collect it, and what would you do with
it when it is eventually available?
6. What functions of production planning and control can be exeroised in con
structing and controlling a timetable for a bus service along a specified route
in a city?