capacity planning rmc
TRANSCRIPT
Operations Management
Capacity Planning
How much long-range capacity is needed
When more capacity is needed
Where facilities should be located (location)
How facilities should be arranged (layout)
Facility planning answers:
Facility Planning
Forecast
Demand
Compute
Needed
Capacity
Compute
Rated
Capacity
Evaluate
Capacity
Plans
Implement
Best Plan
Qualitative
Factors
(e.g., Skills)
Select Best
Capacity
Plan
Develop
Alternative
Plans
Quantitative
Factors
(e.g., Cost)
Capacity Planning Process
Types of Planning Over a Time Horizon
Add FacilitiesAdd long lead time equipment
Schedule JobsSchedule PersonnelAllocate Machinery
Sub-ContractAdd EquipmentAdd Shifts
Add PersonnelBuild or Use Inventory
Long Range Planning
Intermediate Range Planning
Short Range Planning
Modify Capacity Use Capacity
*
*
*Limited options exist
Definition and Measures of Capacity
Capacity: The “throughput,” or number of units a facility
can hold, receive, store, or produce in a period
of time.
Utilization: Actual output as a percent of design capacity.
Effective capacity:
Capacity a firm can expect to receive given its product mix, methods of scheduling, maintenance, and standards of quality.
Efficiency: Actual output as a percent of effective capacity.
Input measures of capacity
Firms operating in low volume, high variety situation
find it relevant
Refining capacity of BPCL refinery in Mumbai is 260,000
barrels of crude per day
Television manufacturer often measures its capacity by
millions of picture tubes that it produces
Tool room facility will measure its capacity in terms of
machine hours
A hospital will measure the capacity in terms of number of
beds.
Output measures of capacity
When the volume of production is high and the variety is relatively
low output measures are useful
Toyota Kirloskar Auto Parts measures it capacity in terms of number
of transmission gear boxes it can produce
Tata Bearings, a division of Tata Steel, has a capacity of 25 million
pieces per annum
MICO Bosch has an installed capacity of one lakh distributor pumps at
its Jaipur plant
An automated car wash facility’s capacity can be measured in terms of
number of cars serviced per day
Actual or Expected Output
Actual (or Expected) Output =
(Effective Capacity)(Efficiency)
Measure of planned or actual capacity usage of a
facility, work center, or machine
UtilizationActual Output
Design Capacity
Planned hours to be used
Total hours available
=
=
Utilization
Capacity Cushion
A capacity cushion is an additional amount of production
capacity added onto the expected demand. e.g. , if the
demand is 10 million pieces p/a and the design capacity is
that of 12 million pieces p/a. then there is a capacity
cushion of 20%.
Capacity utilization rate = capacity used / best operating
level
in the example given above the capacity utilization rate
or efficiency is 100/120 % i.e 83%
Measure of how well a facility or machine is
performing when used
EfficiencyActual output
Effective Capacity
Actual output in units
Standard output in units
Average actual time
Standard time
=
=
=
Efficiency
Determinants of Effective capacity
Facilities- design,location,layout,environmental
factors
Product/Services- product mix ,standardization
Process- quantity vs. quality
Human factors- job design, training, experience,
motivation,manager’s leadership style
Operational factors- scheduling, materials
mgmt.,maintenance.
External factors- product standard, pollution control
etc.
Importance of Capacity
Capacity indicates the ability of a firm to meet the market demand
Inadequate capacity -> may lose customers through slow service or by allowing competitors to enter the market
Excessive capacity -> machine inefficiencies and high cost of production. May reduce price to stimulate demand, under utilize the workforce,carry excessive inventory or seek additional less profitable products to stay in business.
Implications of Capacity Changes
Changes in:
• Sales
• Cash flow
• Quality
• Supply chain
• Human resources
• Maintenance
Special Requirements for Making Good Capacity Decisions
Forecast demand accurately
Understanding the technology and capacity
increments
Finding the optimal operating level (volume)
Build for change
Economies and Diseconomies of
Scale
The basic notion of economies of scale is that as a
plant gets larger and volume increases, the average
cost per unit of output drops. But if the plant is not
operated at its ‘best operating level’ ( either operated
at a higher or lower volume), the diseconomies of
scale results.
One of the major causes of over capacity in industry is
the argument for large facilities to achieve greater
economies of scale.
Output rate (patients per week)
Economies and
Diseconomies of Scale
Ave
rag
e u
nit
co
st
(ru
pe
es
pe
r p
ati
en
t)
250-bed
hospital
Output rate (patients per week)
Economies and
Diseconomies of Scale
Ave
rag
e u
nit
co
st
(ru
pe
es
pe
r p
ati
en
t)
Economies and
Diseconomies of Scale
250-bed
hospital 500-bed
hospital
Output rate (patients per week)
Ave
rag
e u
nit
co
st
(ru
pe
es
pe
r p
ati
en
t)
Economies and
Diseconomies of Scale
250-bed
hospital 500-bed
hospital
Output rate (patients per week)
Economies
of scale
Ave
rag
e u
nit
co
st
(ru
pe
es
pe
r p
ati
en
t)
Economies and
Diseconomies of Scale
250-bed
hospital
750-bed
hospital 500-bed
hospital
Output rate (patients per week)
Economies
of scale
Ave
rag
e u
nit
co
st
(ru
pe
es
pe
r p
ati
en
t)
Economies and
Diseconomies of Scale
Ave
rag
e u
nit
co
st
(ru
pe
es
pe
r p
ati
en
t)
Output rate (patients per week)
250-bed
hospital
750-bed
hospital 500-bed
hospital
Diseconomies
of scale
Economies
of scale
Economies of Scope
It refers to the ability to produce many product
models in one highly flexible production
facility more cheaply than in separate
production facilities.
Strategies for Matching Capacity
to Demand
Short Term Strategies
Long Term Strategies
Short Term StrategiesEmployment levels- hiring/layoff
Workforce utilization- overtime, motivating
Process design- methods improvement
Multiple job training
Maintenance- reduction in breakdown and scheduled maintenance
Minimizing changing over and setup times
Inventorising- carrying out the barest minimum and rest later
Advance preparation
Varying inventories to meet varying customer demand.
Long Term StrategiesIncreasing capacity
Single large step in capacity
Several incremental changes in capacity
Reducing capacity
Selling off existing facilities
Selling off inventory of materials
Retiring and severance of employees
Maintaining capacity at constant level
develop and phase in new products as other products decline
Outsourcing
Sharing capacity
Approaches to Capacity Expansion
Expected Demand
Time in Years
Dem
and
New Capacity
Capacity leads demand with an incremental expansion
Approaches to Capacity ExpansionExpected Demand
Time in Years
Dem
and
New Capacity
Capacity leads demand with a one-step expansion
Approaches to Capacity Expansion
Expected Demand
Time in Years
Dem
and
New Capacity
Capacity lags demand with an incremental expansion
Approaches to Capacity Expansion
Expected Demand
Time in Years
Dem
and
New Capacity
Attempts to have an average capacity, with an incremental
expansion
Approaches to Capacity Expansion
Expected Demand Expected Demand
Expected Demand Expected Demand
Time in Years Time in Years
Time in YearsTime in Years
Dem
and
Dem
and
Dem
and
Dem
and
New Capacity
New CapacityNew Capacity
New Capacity
Capacity leads demand with an incremental expansion Capacity leads demand with a one-step expansion
Capacity lags demand with an incremental expansionAttempts to have an average capacity, with
an incremental expansion
Capacity DecisionsDecision Trees
Capacity DecisionsDecision Trees
1
Capacity DecisionsDecision Trees
Low demand
Low demand
High demand
High demand
1
Capacity DecisionsDecision Trees
Low demand
Low demand
High demand
High demand
Don’t expand
Expand1
2
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
High demand [0.60]
High demand [0.60]
Don’t expand
Expand1
2
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Expected Payoff = Event * Event Probability
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70k
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Expected Payoff = Event * Event Probability
Small/Low = Rs.70K (0.40)
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Expected Payoff = Event * Event Probability
Small/Low = Rs.70K (0.40) = Rs.28K
Small/High = Rs.135K (0.60)
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Expected Payoff = Event * Event Probability
Small/Low = Rs.70K (0.40) = Rs.28K
Small/High = Rs.135K (0.60) = Rs.81K
Small = Rs.28K + Rs.81K = Rs.109K
Rs.109K
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Expected Payoff = Event * Event Probability
Large/Low = Rs.40K (0.40) = Rs.16K
Large/High = Rs.220K (0.60) = Rs.132K
Large = Rs.16K + Rs.132K = Rs.148K
Rs.109K
Rs.148K
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
Rs.148K
Rs.109K
Rs.148K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Capacity DecisionsDecision Trees
Low demand [0.40]
Low demand [0.40]
Rs.70K
Rs.220K
Rs.40K
Rs.148K
Rs.109K
Rs.148K
High demand [0.60]
High demand [0.60]
Rs.135K
Don’t expand
ExpandRs.135K
Rs.90K
1
2
Capacity Bottlenecks
A bottleneck is an operation that has the
lowest effective capacity of any operation in
the process and thus limits the system’s
output.
Capacity Bottlenecks
InputsTo
customers
(a) Operation 2 a bottleneck
50/hr
1 2 3
200/hr 200/hr
(b) All operations bottlenecks
2 31InputsTo
customers200/hr 200/hr 200/hr
Capacity Bottlenecks