Slovak University of Technology
Faculty of Material Science and Technology in Trnava
Planning in
production systems
Resource and capacity planning
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Resource planning is a set of forward planning
tools to help people balance future demand and
supply, to predict capacity problems with enough
time to do something about them, to create a
load leveled master schedule, and to project
supplier requirements well in advance.
Manufacturing planning and control entails the
acquisition and allocation of limited resources to
production activities so as to satisfy customer
demand over a specified time horizon.
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Production planning, at its core, production
planning represents the beating heart of any
manufacturing process. Its purpose is to
minimize production time and costs, efficiently
organize the use of resources and maximize
efficiency in the workplace.
The identification of the relevant costs is also an
important issue.
A planning problem exists because there are
limited production resources that cannot be
stored from period to period.
Capacity planning
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Capacity planning is the process of determining
the production capacity needed by an
organization to meet changing demands for its
products. In the context of capacity planning,
"capacity" is the maximum amount of work that
an organization is capable of completing in a
given period of time.
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A discrepancy between the capacity of an
organization and the demands of its customers
results in inefficiency, either in under-utilized
resources or unfulfilled customers. The goal of
capacity planning is to minimize this
discrepancy.
Demand for an organization's capacity varies
based on changes in production output, such as
increasing or decreasing the production quantity
of an existing product, or producing new
products. Better utilization of existing capacity
can be accomplished through improvements in
Overall Equipment Effectiveness.
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Capacity can be increased through introducing
new techniques, equipment and materials,
increasing the number of workers or machines,
increasing the number of shifts, or acquiring
additional production facilities.
Capacity is calculated: (number of machines or
workers) x (number of shifts) x (utilization) x
(efficiency).
Utilization of the production facilities -> 70-80%
 Desirable
increase of capacity utilization
 The less utilization – the more expensive production
 The better capacity utilization – the better productivity
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Production lines
 First
is known the product, time structure and after
that are the machines obtained.
 It is not allowed to occur the idle capacity -> the are
used single-purpose machines
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Minor types of manufacturing
 there
are machines, and after that is recognized,
which products is the company able to produce
Methods of planning the utilization
capacity
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Forward planning:
 Forward
plan is a document that results from the
process of forward planning. In broad terms it sets out
the aims and objectives of your organization over a
defined period, matched against resources and staff
responsibilities.
 A forward plan can be as long or as short as
necessary, depending on the scale of your
organization and what is appropriate to you, but it
should always include an associated action plan.
Backward assembly planning
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An assembly planning system that operates
based on a recursive decomposition of
assembly into sub assemblies, and analyzes
assembly cost in terms of stability, directionality,
and manipulability to guide the generation of
preferred assembly plans.
The planning in this system incorporates the
special processes, such as cleaning, testing,
labeling, etc. that must occur during the
assembly, and handles non reversible as well as
reversible assembly tasks through backward
assembly planning.
Capacity and time restrictions
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Causes conflicts, which have to be solved ->
there exists 2 possibilities:
 it
is necessary to take into deliberate the real
capacities (capacity restrictions) and then is build the
schedule – it is used by forward planning
 Capacities are quasi infinite and there are used terms
required by the user. In case of the conflict possibility,
i its necessary to solve this problem (supplementary
capacities or modification of the Schedule) - it is used
by backward planning
Operative plan capacity balancing
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Aim of the capacity balancing
 Possibilities
verification of planned production tasts by
hardware device and by workers
 Measure adoption for production tasks harmonization
with possibilities of production
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Capacity balancing steps
 setting
the production capacity
 setting the capacity for planned production tasks
realization
 comparison of disposable and necessary production
capacity and receiving arrangement for disproportion
removing
Setting the production capacity
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Capacity
 Capacity
planning is the process of determining the
production capacity needed by an organization to
meet changing demands for its products.
 Capacity of the production unit may be determined by
many ways and express in natural, time and value
units of measure
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The most objective and most exact expression
of the production capacity is in natural units
 Amount
of definite products, which certain production
facility or a group of production facilities is able to
produce in certain period
 use – for capacity balancing only in conditions of
higher types manufacturing (production in large
series, mass production with small range of goods
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production capacity expression in time units
 maximum
possible time usage of the machinery,
workers or production plane in some period
 expression by the time fund – calendar, nominal and
effective time fund
 calendar
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conjunction of calendar days in a year (365 days) and hours
in a day (24h)
is the base of capacity production of continual production
 Nominal
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time fund
conjunction of workdays and hours in working shift (in
machine industry usually 2 shifts = 16 hours)
 Effective
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time fund
time fund
determined on the base of nominal time fund, by subtractions
of the time needed for repairs and machinery adjusting
Setting the capacity necessity for
operative plan tasks assurance
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The second step the operative plans of the
capacity balancing is the calculation of the
capacitive load with plan tasks.
Self capacity balancing
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Disposable capacity comparison to capacity
consumption ® usually is determined the
existence of capacitive disproportion
Capacity and resources planning
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After setting the time of production preparation,
times needed for individual operation, date of
start and production finish -> capacity plan
verification – if there are available capacities the goal is to assure observance of terms and
cut-down the idle time
Costs planning target – total costs definition for
job realization and its minimalization
Production capacity of the
machines and production facilities
calculation
Qp = Tp * Vp
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Qp
Tp
Vp
- production capacity couched in natural units
- usable time fund in hours
- power in natural units per 1 hour
The production capacity calculation through the
capacity of work difficulty – used in machine
manufacturing by mechanical working
tk =
t
k1 * k2
tk
t
k1
k2
- capacity of the work difficulty in hours
- standard of the work difficulty in nh (normohours)
- standard fulfilling index
- progression index
Calculation of the production capacity:
Qp =
Tp
tk
kc
Qs
Qp
kc =
Qs
Qp
- total production capacity utilization coefficient
- real production volume
- production capacity
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Factors that affect the level of production
capacity utilization
 production
plan
 real working time
 machinery performance utilization
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Capacitive reserve – production volume, which
can be able to be produced by full production
capacity utilization
 divergence
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Qp - Qs
total production capacity utilization coefficient
 synthetic
 real
indicator
reached volume of production Qs
if is the production capacity calculated by formula
T
Qp = t p
k
i.e. through the usage of capacitive standard of work
expenditure, it is possible to measure it as follows:
Qs
Qp
=
Ts
Tp
tk
ts
ts - real work expenditure of the product